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Mehla J, Deibel SH, Karem H, Hong NS, Hossain SR, Lacoursiere SG, Sutherland RJ, Mohajerani MH, McDonald RJ. Repeated multi-domain cognitive training prevents cognitive decline, anxiety and amyloid pathology found in a mouse model of Alzheimer disease. Commun Biol 2023; 6:1145. [PMID: 37950055 PMCID: PMC10638434 DOI: 10.1038/s42003-023-05506-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Accepted: 10/25/2023] [Indexed: 11/12/2023] Open
Abstract
Education, occupation, and an active lifestyle, comprising enhanced social, physical, and mental components are associated with improved cognitive functions in aged people and may delay the progression of various neurodegenerative diseases including Alzheimer's disease. To investigate this protective effect, 3-month-old APPNL-G-F/NL-G-F mice were exposed to repeated single- or multi-domain cognitive training. Cognitive training was given at the age of 3, 6, & 9 months. Single-domain cognitive training was limited to a spatial navigation task. Multi-domain cognitive training consisted of a spatial navigation task, object recognition, and fear conditioning. At the age of 12 months, behavioral tests were completed for all groups. Then, mice were sacrificed, and their brains were assessed for pathology. APPNL-G-F/NL-G-F mice given multi-domain cognitive training compared to APPNL-G-F/NL-G-F control group showed an improvement in cognitive functions, reductions in amyloid load and microgliosis, and a preservation of cholinergic function. Additionally, multi-domain cognitive training improved anxiety in APPNL-G-F/NL-G-F mice as evidenced by measuring thigmotaxis behavior in the Morris water maze. There were mild reductions in microgliosis in the brain of APPNL-G-F/NL-G-F mice with single-domain cognitive training. These findings provide causal evidence for the potential of certain forms of cognitive training to mitigate the cognitive deficits in Alzheimer disease.
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Affiliation(s)
- Jogender Mehla
- Canadian Centre for Behavioural Neuroscience, University of Lethbridge, Lethbridge, AB, Canada
- Department of Neurological Surgery, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Scott H Deibel
- Canadian Centre for Behavioural Neuroscience, University of Lethbridge, Lethbridge, AB, Canada
- Department of Psychology, University of New Brunswick, POB 4400, Fredericton, NB, E3B 3A1, Canada
| | - Hadil Karem
- Canadian Centre for Behavioural Neuroscience, University of Lethbridge, Lethbridge, AB, Canada
| | - Nancy S Hong
- Canadian Centre for Behavioural Neuroscience, University of Lethbridge, Lethbridge, AB, Canada
| | - Shakhawat R Hossain
- Canadian Centre for Behavioural Neuroscience, University of Lethbridge, Lethbridge, AB, Canada
| | - Sean G Lacoursiere
- Canadian Centre for Behavioural Neuroscience, University of Lethbridge, Lethbridge, AB, Canada
| | - Robert J Sutherland
- Canadian Centre for Behavioural Neuroscience, University of Lethbridge, Lethbridge, AB, Canada
| | - Majid H Mohajerani
- Canadian Centre for Behavioural Neuroscience, University of Lethbridge, Lethbridge, AB, Canada.
| | - Robert J McDonald
- Canadian Centre for Behavioural Neuroscience, University of Lethbridge, Lethbridge, AB, Canada.
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Shaikh A, Ahmad F, Teoh SL, Kumar J, Yahaya MF. Honey and Alzheimer's Disease-Current Understanding and Future Prospects. Antioxidants (Basel) 2023; 12:antiox12020427. [PMID: 36829985 PMCID: PMC9952506 DOI: 10.3390/antiox12020427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 01/30/2023] [Accepted: 02/03/2023] [Indexed: 02/12/2023] Open
Abstract
Alzheimer's disease (AD), a leading cause of dementia, has been a global concern. AD is associated with the involvement of the central nervous system that causes the characteristic impaired memory, cognitive deficits, and behavioral abnormalities. These abnormalities caused by AD is known to be attributed by extracellular aggregates of amyloid beta plaques and intracellular neurofibrillary tangles. Additionally, genetic factors such as abnormality in the expression of APOE, APP, BACE1, PSEN-1, and PSEN-2 play a role in the disease. As the current treatment aims to treat the symptoms and to slow the disease progression, there has been a continuous search for new nutraceutical agent or medicine to help prevent and cure AD pathology. In this quest, honey has emerged as a powerful nootropic agent. Numerous studies have demonstrated that the high flavonoids and phenolic acids content in honey exerts its antioxidant, anti-inflammatory, and neuroprotective properties. This review summarizes the effect of main flavonoid compounds found in honey on the physiological functioning of the central nervous system, and the effect of honey intake on memory and cognition in various animal model. This review provides a new insight on the potential of honey to prevent AD pathology, as well as to ameliorate the damage in the developed AD.
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Affiliation(s)
- Ammara Shaikh
- Department of Anatomy, Faculty of Medicine, Universiti Kebangsaan Malaysia, Kuala Lumpur 56000, Malaysia
| | - Fairus Ahmad
- Department of Anatomy, Faculty of Medicine, Universiti Kebangsaan Malaysia, Kuala Lumpur 56000, Malaysia
| | - Seong Lin Teoh
- Department of Anatomy, Faculty of Medicine, Universiti Kebangsaan Malaysia, Kuala Lumpur 56000, Malaysia
| | - Jaya Kumar
- Department of Physiology, Faculty of Medicine, Universiti Kebangsaan Malaysia, Kuala Lumpur 56000, Malaysia
| | - Mohamad Fairuz Yahaya
- Department of Anatomy, Faculty of Medicine, Universiti Kebangsaan Malaysia, Kuala Lumpur 56000, Malaysia
- Correspondence:
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3
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Wu Z, Buckley MJ. Prefrontal and Medial Temporal Lobe Cortical Contributions to Visual Short-Term Memory. J Cogn Neurosci 2022; 35:27-43. [PMID: 36306260 DOI: 10.1162/jocn_a_01937] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
A number of recent studies have indicated that the medial temporal lobe (MTL) plays a critical role in working memory (WM) and perception, but these results have been highly controversial given the traditional association of MTL with long-term memory. We review the research and highlight important factors that need to be considered in determining the role of MTL in WM including set-size of used stimuli and feature complexity and/or feature conjunctions/bindings embedded in those stimuli. These factors relate to hierarchical and, accordingly, domain-specific theories of functional organization within the temporal lobe. In addition, one must consider process-specific theories too, because two key processes commonly understood to contribute recognition memory, namely, recollection and familiarity, also have robust support from neurophysiological and neuroimaging research as to their functional dissociations within MTL. PFC has long been heavily implicated in WM; however, relatively less is known about how the PFC contributes to recollection and familiarity, although dynamic prefrontal coding models in WM may help to explain their neural mechanisms. The MTL and PFC are heavily interconnected and do not operate independently in underlying WM. We propose that investigation of the interactions between these two regions in WM, particularly their coordinated neural activities, and the modeling of such interactions, will be crucial for the advancing understanding of the neural mechanisms of WM.
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Affiliation(s)
- Zhemeng Wu
- University of Oxford, United Kingdom.,University of Toronto, Ontario, Canada
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4
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Mehla J, Deibel SH, Karem H, Hossain S, Lacoursiere SG, Sutherland RJ, Mohajerani MH, McDonald RJ. Dramatic impacts on brain pathology, anxiety, and cognitive function in the knock-in APPNL-G-F mouse model of Alzheimer disease following long-term voluntary exercise. Alzheimers Res Ther 2022; 14:143. [PMID: 36180883 PMCID: PMC9526288 DOI: 10.1186/s13195-022-01085-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Accepted: 09/13/2022] [Indexed: 11/22/2022]
Abstract
Background An active lifestyle is associated with improved cognitive functions in aged people and may prevent or slow down the progression of various neurodegenerative diseases including Alzheimer’s disease (AD). To investigate these protective effects, male APPNL-G-F mice were exposed to long-term voluntary exercise. Methods Three-month-old AD mice were housed in a cage supplemented with a running wheel for 9 months for long-term exercise. At the age of 12 months, behavioral tests were completed for all groups. After completing behavioral testing, their brains were assessed for amyloid pathology, microgliosis, and cholinergic cells. Results The results showed that APPNL-G-F mice allowed to voluntarily exercise showed an improvement in cognitive functions. Furthermore, long-term exercise also improved anxiety in APPNL-G-F mice as assessed by measuring thigmotaxis in the Morris water task. We also found reductions in amyloid load and microgliosis, and a preservation of cholinergic cells in the brain of APPNL-G-F mice allowed to exercise in their home cages. These profound reductions in brain pathology associated with AD are likely responsible for the observed improvement of learning and memory functions following extensive and regular exercise. Conclusion These findings suggest the potential of physical exercise to mitigate the cognitive deficits in AD.
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Charlton AJ, Perry CJ. The Effect of Chronic Alcohol on Cognitive Decline: Do Variations in Methodology Impact Study Outcome? An Overview of Research From the Past 5 Years. Front Neurosci 2022; 16:836827. [PMID: 35360176 PMCID: PMC8960615 DOI: 10.3389/fnins.2022.836827] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 01/27/2022] [Indexed: 11/24/2022] Open
Abstract
Excessive alcohol use is often associated with accelerated cognitive decline, and extensive research using animal models of human alcohol consumption has been conducted into potential mechanisms for this relationship. Within this literature there is considerable variability in the types of models used. For example, alcohol administration style (voluntary/forced), length and schedule of exposure and abstinence period are often substantially different between studies. In this review, we evaluate recent research into alcohol-induced cognitive decline according to methodology of alcohol access, as well as cognitive behavioral task employed. Our aim was to query whether the nature and severity of deficits observed may be impacted by the schedule and type of alcohol administration. We furthermore examined whether there is any apparent relationship between the amount of alcohol consumed and the severity of the deficit, as well as the potential impact of abstinence length, and other factors such as age of administration, and sex of subject. Over the past five years, researchers have overwhelmingly used non-voluntary methods of intake, however deficits are still found where intake is voluntary. Magnitude of intake and type of task seem most closely related to the likelihood of producing a deficit, however even this did not follow a consistent pattern. We highlight the importance of using systematic and clear reporting styles to facilitate consistency across the literature in this regard. We hope that this analysis will provide important insights into how experimental protocols might influence findings, and how different patterns of consumption are more or less likely to produce an addiction-vulnerable cognitive phenotype in animal models.
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Affiliation(s)
- Annai J. Charlton
- Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia
- Florey Department of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia
| | - Christina J. Perry
- Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia
- School of Psychological Sciences, Centre for Emotional Health, Macquarie University, North Ryde, NSW, Australia
- *Correspondence: Christina J. Perry,
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Albazal A, Delshad AA, Roghani M. Melatonin reverses cognitive deficits in streptozotocin-induced type 1 diabetes in the rat through attenuation of oxidative stress and inflammation. J Chem Neuroanat 2020; 112:101902. [PMID: 33276072 DOI: 10.1016/j.jchemneu.2020.101902] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 11/06/2020] [Accepted: 11/28/2020] [Indexed: 12/30/2022]
Abstract
Uncontrolled diabetes mellitus (DM) is linked to attentional deficits and cognition deterioration. The neurohormone melatonin is an endogenous synchronizer of circadian rhythms with multiple protective properties. This research was designed to assess its effect against learning and memory decline in streptozotocin (STZ)-induced diabetic rats. Rats were assigned to control, melatonin-treated control, diabetic, and melatonin-treated diabetic groups. Melatonin was administered i.p. at a dose of 10 mg/kg/day for 47 days. Treatment of diabetic rats with melatonin reversed decline of spatial recognition memory in Y maze, performance of rats in novel object discrimination, and retention and recall in passive avoidance tasks. Furthermore, melatonin appropriately attenuated hippocampal malondialdehyde (MDA) and reactive oxygen species (ROS) and improved superoxide dismutase (SOD) activity and improved mitochondrial membrane potential (MMP) and nuclear factor (erythroid-derived 2)-like 2 (Nrf2) with no significant effect on nitrite, glutathione (GSH) and catalase activity. Besides, hippocampal level of acetylcholinesterase (AChE), glial fibrillary acidic protein (GFAP), nuclear factor-kappaB (NF-κB), interleukin 6 (IL-6) and tumor necrosis factor α (TNFα) decreased following melatonin treatment. There was also a reduction of dendritic spines of pyramidal neurons of hippocampal CA1 area in diabetic group that was significantly alleviated upon melatonin treatment. Melatonin could ameliorate learning and memory disturbances in diabetic rats through mitigation of cholinesterase activity, astrocytes, oxidative stress and inflammation and also via upregulation of some antioxidants in addition to its prevention of dendritic spine loss.
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Affiliation(s)
- Ala Albazal
- School of Medicine, Shahed University, Tehran, Iran
| | | | - Mehrdad Roghani
- Neurophysiology Research Center, Shahed University, Tehran, Iran.
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7
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Selvakumar GP, Ahmed ME, Iyer SS, Thangavel R, Kempuraj D, Raikwar SP, Bazley K, Wu K, Khan A, Kukulka K, Bussinger B, Zaheer S, Burton C, James D, Zaheer A. Absence of Glia Maturation Factor Protects from Axonal Injury and Motor Behavioral Impairments after Traumatic Brain Injury. Exp Neurobiol 2020; 29:230-248. [PMID: 32565489 PMCID: PMC7344375 DOI: 10.5607/en20017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Revised: 06/09/2020] [Accepted: 06/09/2020] [Indexed: 12/11/2022] Open
Abstract
Traumatic brain injury (TBI) causes disability and death, accelerating the progression towards Alzheimer's disease and Parkinson's disease (PD). TBI causes serious motor and cognitive impairments, as seen in PD that arise during the period of the initial insult. However, this has been understudied relative to TBI induced neuroinflammation, motor and cognitive decline that progress towards PD. Neuronal ubiquitin-C-terminal hydrolase- L1 (UCHL1) is a thiol protease that breaks down ubiquitinated proteins and its level represents the severity of TBI. Previously, we demonstrated the molecular action of glia maturation factor (GMF); a proinflammatory protein in mediating neuroinflammation and neuronal loss. Here, we show that the weight drop method induced TBI neuropathology using behavioral tests, western blotting, and immunofluorescence techniques on sections from wild type (WT) and GMF-deficient (GMF-KO) mice. Results reveal a significant improvement in substantia nigral tyrosine hydroxylase and dopamine transporter expression with motor behavioral performance in GMF-KO mice following TBI. In addition, a significant reduction in neuroinflammation was manifested, as shown by activation of nuclear factor-kB, reduced levels of inducible nitric oxide synthase, and cyclooxygenase- 2 expressions. Likewise, neurotrophins including brain-derived neurotrophic factor and glial-derived neurotrophic factor were significantly improved in GMF-KO mice than WT 72 h post-TBI. Consistently, we found that TBI enhances GFAP and UCHL-1 expression and reduces the number of dopaminergic TH-positive neurons in WT compared to GMF-KO mice 72 h post-TBI. Interestingly, we observed a reduction of THpositive tanycytes in the median eminence of WT than GMF-KO mice. Overall, we found that absence of GMF significantly reversed these neuropathological events and improved behavioral outcome. This study provides evidence that PD-associated pathology progression can be initiated upon induction of TBI.
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Affiliation(s)
- Govindhasamy Pushpavathi Selvakumar
- Harry S. Truman Memorial Veterans Hospital, Columbia, Missouri 65211, USA.,Department of Neurology, School of Medicine, University of Missouri, Columbia, Missouri 65211, USA.,Center for Translational Neuroscience, School of Medicine, University of Missouri, Columbia, Missouri 65211, USA
| | - Mohammad Ejaz Ahmed
- Harry S. Truman Memorial Veterans Hospital, Columbia, Missouri 65211, USA.,Department of Neurology, School of Medicine, University of Missouri, Columbia, Missouri 65211, USA.,Center for Translational Neuroscience, School of Medicine, University of Missouri, Columbia, Missouri 65211, USA
| | - Shankar S Iyer
- Harry S. Truman Memorial Veterans Hospital, Columbia, Missouri 65211, USA.,Department of Neurology, School of Medicine, University of Missouri, Columbia, Missouri 65211, USA.,Center for Translational Neuroscience, School of Medicine, University of Missouri, Columbia, Missouri 65211, USA
| | - Ramasamy Thangavel
- Harry S. Truman Memorial Veterans Hospital, Columbia, Missouri 65211, USA.,Department of Neurology, School of Medicine, University of Missouri, Columbia, Missouri 65211, USA.,Center for Translational Neuroscience, School of Medicine, University of Missouri, Columbia, Missouri 65211, USA
| | - Duraisamy Kempuraj
- Harry S. Truman Memorial Veterans Hospital, Columbia, Missouri 65211, USA.,Department of Neurology, School of Medicine, University of Missouri, Columbia, Missouri 65211, USA.,Center for Translational Neuroscience, School of Medicine, University of Missouri, Columbia, Missouri 65211, USA
| | - Sudhanshu P Raikwar
- Harry S. Truman Memorial Veterans Hospital, Columbia, Missouri 65211, USA.,Department of Neurology, School of Medicine, University of Missouri, Columbia, Missouri 65211, USA.,Center for Translational Neuroscience, School of Medicine, University of Missouri, Columbia, Missouri 65211, USA
| | - Kieran Bazley
- Department of Neurology, School of Medicine, University of Missouri, Columbia, Missouri 65211, USA.,Center for Translational Neuroscience, School of Medicine, University of Missouri, Columbia, Missouri 65211, USA
| | - Kristopher Wu
- Department of Neurology, School of Medicine, University of Missouri, Columbia, Missouri 65211, USA.,Center for Translational Neuroscience, School of Medicine, University of Missouri, Columbia, Missouri 65211, USA
| | - Asher Khan
- Department of Neurology, School of Medicine, University of Missouri, Columbia, Missouri 65211, USA.,Center for Translational Neuroscience, School of Medicine, University of Missouri, Columbia, Missouri 65211, USA
| | - Klaudia Kukulka
- Department of Neurology, School of Medicine, University of Missouri, Columbia, Missouri 65211, USA.,Center for Translational Neuroscience, School of Medicine, University of Missouri, Columbia, Missouri 65211, USA
| | - Bret Bussinger
- Department of Neurology, School of Medicine, University of Missouri, Columbia, Missouri 65211, USA.,Center for Translational Neuroscience, School of Medicine, University of Missouri, Columbia, Missouri 65211, USA
| | - Smita Zaheer
- Department of Neurology, School of Medicine, University of Missouri, Columbia, Missouri 65211, USA.,Center for Translational Neuroscience, School of Medicine, University of Missouri, Columbia, Missouri 65211, USA
| | | | | | - Asgar Zaheer
- Harry S. Truman Memorial Veterans Hospital, Columbia, Missouri 65211, USA.,Department of Neurology, School of Medicine, University of Missouri, Columbia, Missouri 65211, USA.,Center for Translational Neuroscience, School of Medicine, University of Missouri, Columbia, Missouri 65211, USA
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8
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Wang Z, Lin B, Liu W, Peng H, Song C, Huang J, Li Z, Chen L, Tao J. Electroacupuncture ameliorates learning and memory deficits via hippocampal 5-HT1A receptors and the PKA signaling pathway in rats with ischemic stroke. Metab Brain Dis 2020; 35:549-558. [PMID: 31515682 DOI: 10.1007/s11011-019-00489-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2017] [Accepted: 08/28/2019] [Indexed: 12/22/2022]
Abstract
Hippocampal 5-HT1A receptors and the PKA signaling pathway have been implicated in learning and memory. This study aimed to investigate whether PKA signaling mediated by 5-HT1A receptors was involved in the electroacupuncture (EA)-mediated learning and memory in a rat model of middle cerebral artery occlusion-induced cognitive deficit (MICD). Compared to no treatment or non-acupoint EA treatment, EA at DU20 and DU24 acupoints improved the neurological deficit of scores, shortened escape latency and increased the frequency of crossing the platform in the Morris water maze test. T2-weighted imaging demonstrated that the MICD rat brain lesions were mainly located in the cortex and hippocampus, and injured volumes were reduced after EA. Furthermore, we found that these behavioral changes were concomitant with the deficit of the 5HT1A and PKA signaling pathways in the hippocampus, as the activation of the 5-HT1A receptor, the reduction of PKA kinase activity, and AMPA and NMDA receptor phosphorylation occurred in the injured hippocampus at Day 14 after MICD. Additionally, EA dramatically elevated the activation of PKA. Moreover, EA significantly increased intracellular calcium concentrations regulated by the activation of NMDA receptors. Therefore, PKA kinase and NMDA receptors mediated by 5-HT1A receptors in the hippocampus might contribute to improving learning and memory during the recovery process following ischemic stroke with an EA intervention.
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Affiliation(s)
- Zhifu Wang
- Fujian University of Traditional Chinese Medicine, Fuzhou, China
| | - Bingbing Lin
- Fujian University of Traditional Chinese Medicine, Fuzhou, China
| | - Weilin Liu
- Fujian University of Traditional Chinese Medicine, Fuzhou, China
| | - Hongwei Peng
- Fujian University of Traditional Chinese Medicine, Fuzhou, China
| | - Changming Song
- Fujian University of Traditional Chinese Medicine, Fuzhou, China
| | - Jia Huang
- Fujian University of Traditional Chinese Medicine, Fuzhou, China
| | - Zuanfang Li
- Fujian University of Traditional Chinese Medicine, Fuzhou, China
| | - Lidian Chen
- Fujian University of Traditional Chinese Medicine, Fuzhou, China
| | - Jing Tao
- Fujian University of Traditional Chinese Medicine, Fuzhou, China.
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9
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Mineur YS, Picciotto MR. The role of acetylcholine in negative encoding bias: Too much of a good thing? Eur J Neurosci 2019; 53:114-125. [PMID: 31821620 DOI: 10.1111/ejn.14641] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Revised: 11/19/2019] [Accepted: 11/26/2019] [Indexed: 12/28/2022]
Abstract
Optimal acetylcholine (ACh) signaling is important for sustained attention and facilitates learning and memory. At the same time, human and animal studies have demonstrated increased levels of ACh in the brain during depressive episodes and increased symptoms of anxiety, depression, and reactivity to stress when ACh breakdown is impaired. While it is possible that the neuromodulatory roles of ACh in cognitive and affective processes are distinct, one possibility is that homeostatic levels of ACh signaling are necessary for appropriate learning, but overly high levels of cholinergic signaling promote encoding of stressful events, leading to the negative encoding bias that is a core symptom of depression. In this review, we outline this hypothesis and suggest potential neural pathways and underlying mechanisms that may support a role for ACh signaling in negative encoding bias.
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Affiliation(s)
- Yann S Mineur
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA
| | - Marina R Picciotto
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA
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10
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Sun Y, Gao Y, Tidei JJ, Shen M, Hoang JT, Wagner DF, Zhao X. Loss of MeCP2 in immature neurons leads to impaired network integration. Hum Mol Genet 2019; 28:245-257. [PMID: 30277526 DOI: 10.1093/hmg/ddy338] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2018] [Accepted: 09/18/2018] [Indexed: 12/12/2022] Open
Abstract
Rett syndrome (RTT) is a neurodevelopmental disorder caused by mutations or deletions in Methyl-CpG-binding Protein 2 (MeCP2), a brain-enriched transcriptional regulator. MeCP2 is highly expressed during neuronal maturation and its deficiency results in impaired dendritic morphogenesis and reduced dendritic spine numbers in developing neurons. However, whether MeCP2 deficiency impacts the integration of new neurons has not been directly assessed. In this study, we developed a modified rabies virus-mediated monosynaptic retrograde tracing method to interrogate presynaptic integration of MeCP2-deficient new neurons born in the adult hippocampus, a region with lifelong neurogenesis and plasticity. We found that selective deletion of MeCP2 in adult-born new neurons impaired their long-range connectivity to the cortex, whereas their connectivity within the local hippocampal circuits or with subcortical regions was not significantly affected. We further showed that knockdown of MeCP2 in primary hippocampal neurons also resulted in reduced network integration. Interestingly, (1-3) insulin-like growth factor-1 (IGF-1), a small peptide under clinical trial testing for RTT, rescued neuronal integration deficits of MeCP2-deficient neurons in vitro but not in vivo. In addition, (1-3) IGF-1 treatment corrected aberrant excitability and network synchrony of MeCP2-deficient hippocampal neurons. Our results indicate that MeCP2 is essential for immature neurons to establish appropriate network connectivity.
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Affiliation(s)
- Yi Sun
- National Key Research Laboratory of Natural and Biomimetic Drugs.,Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University, Beijing, PR China.,Waisman Center
| | - Yu Gao
- Waisman Center.,Department of Neuroscience
| | | | | | | | | | - Xinyu Zhao
- Waisman Center.,Department of Neuroscience.,Cellular and Molecular Biology Program, University of Wisconsin-Madison, Madison, WI, USA
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11
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Robin J, Rai Y, Valli M, Olsen RK. Category specificity in the medial temporal lobe: A systematic review. Hippocampus 2018; 29:313-339. [PMID: 30155943 DOI: 10.1002/hipo.23024] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 08/03/2018] [Accepted: 08/07/2018] [Indexed: 01/30/2023]
Abstract
Theoretical accounts of medial temporal lobe (MTL) function ascribe different functions to subregions of the MTL including perirhinal, entorhinal, parahippocampal cortices, and the hippocampus. Some have suggested that the functional roles of these subregions vary in terms of their category specificity, showing preferential coding for certain stimulus types, but the evidence for this functional organization is mixed. In this systematic review, we evaluate existing evidence for regional specialization in the MTL for three categories of visual stimuli: faces, objects, and scenes. We review and synthesize across univariate and multivariate neuroimaging studies, as well as neuropsychological studies of cases with lesions to the MTL. Neuroimaging evidence suggests that faces activate the perirhinal cortex, entorhinal cortex, and the anterior hippocampus, while scenes engage the parahippocampal cortex and both the anterior and posterior hippocampus, depending on the contrast condition. There is some evidence for object-related activity in anterior MTL regions when compared to scenes, and in posterior MTL regions when compared to faces, suggesting that aspects of object representations may share similarities with face and scene representations. While neuroimaging evidence suggests some hippocampal specialization for faces and scenes, neuropsychological evidence shows that hippocampal damage leads to impairments in scene memory and perception, but does not entail equivalent impairments for faces in cases where the perirhinal cortex remains intact. Regional specialization based on stimulus categories has implications for understanding the mechanisms of MTL subregions, and highlights the need for the development of theoretical models of MTL function that can accommodate the differential patterns of specificity observed in the MTL.
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Affiliation(s)
- Jessica Robin
- Rotman Research Institute, Baycrest Health Sciences, Toronto, Ontario, Canada
| | - Yeshith Rai
- Rotman Research Institute, Baycrest Health Sciences, Toronto, Ontario, Canada
| | - Mikaeel Valli
- Rotman Research Institute, Baycrest Health Sciences, Toronto, Ontario, Canada.,Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Rosanna K Olsen
- Rotman Research Institute, Baycrest Health Sciences, Toronto, Ontario, Canada.,Department of Psychology, University of Toronto, Toronto, Ontario, Canada
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12
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Wideman CE, Jardine KH, Winters BD. Involvement of classical neurotransmitter systems in memory reconsolidation: Focus on destabilization. Neurobiol Learn Mem 2018; 156:68-79. [DOI: 10.1016/j.nlm.2018.11.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 10/09/2018] [Accepted: 11/01/2018] [Indexed: 10/27/2022]
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13
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Rolls ET. The storage and recall of memories in the hippocampo-cortical system. Cell Tissue Res 2018; 373:577-604. [PMID: 29218403 PMCID: PMC6132650 DOI: 10.1007/s00441-017-2744-3] [Citation(s) in RCA: 99] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Accepted: 11/12/2017] [Indexed: 02/07/2023]
Abstract
A quantitative computational theory of the operation of the hippocampus as an episodic memory system is described. The CA3 system operates as a single attractor or autoassociation network (1) to enable rapid one-trial associations between any spatial location (place in rodents or spatial view in primates) and an object or reward and (2) to provide for completion of the whole memory during recall from any part. The theory is extended to associations between time and object or reward to implement temporal order memory, which is also important in episodic memory. The dentate gyrus performs pattern separation by competitive learning to create sparse representations producing, for example, neurons with place-like fields from entorhinal cortex grid cells. The dentate granule cells generate, by the very small number of mossy fibre connections to CA3, a randomizing pattern separation effect that is important during learning but not recall and that separates out the patterns represented by CA3 firing as being very different from each other. This is optimal for an unstructured episodic memory system in which each memory must be kept distinct from other memories. The direct perforant path input to CA3 is quantitatively appropriate for providing the cue for recall in CA3 but not for learning. The CA1 recodes information from CA3 to set up associatively learned backprojections to the neocortex to allow the subsequent retrieval of information to the neocortex, giving a quantitative account of the large number of hippocampo-neocortical and neocortical-neocortical backprojections. Tests of the theory including hippocampal subregion analyses and hippocampal NMDA receptor knockouts are described and support the theory.
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Affiliation(s)
- Edmund T Rolls
- Oxford Centre for Computational Neuroscience, Oxford, England.
- Department of Computer Science, University of Warwick, Coventry, England.
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Prospective Analysis of the Effects of Maternal Immune Activation on Rat Cytokines during Pregnancy and Behavior of the Male Offspring Relevant to Schizophrenia. eNeuro 2018; 5:eN-NWR-0249-18. [PMID: 30225350 PMCID: PMC6140112 DOI: 10.1523/eneuro.0249-18.2018] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 07/31/2018] [Accepted: 08/06/2018] [Indexed: 02/04/2023] Open
Abstract
Influenza during pregnancy is associated with the development of psychopathology in the offspring. We sought to determine whether maternal cytokines produced following administration of viral mimetic polyinosinic-polycytidylic acid (polyI:C) to pregnant rats were predictive of behavioral abnormalities in the adult offspring. Timed-pregnant Sprague Dawley rats received a single intravenous injection of 4-mg/kg polyI:C or saline on gestational day (GD)15. Blood was collected 3 h later for serum analysis of cytokine levels with ELISA. Male offspring were tested in a battery of behavioral tests during adulthood and behavior was correlated with maternal cytokine levels. Maternal serum levels of CXCL1 and interleukin (IL)-6, but not tumor necrosis factor (TNF)-α or CXCL2, were elevated in polyI:C-treated dams. PolyI:C-treated dams experienced post-treatment weight loss and polyI:C pups were smaller than controls at postnatal day (PND)1. Various behavior alterations were seen in the polyI:C-treated offspring. Male polyI:C offspring had enhanced MK-801-induced locomotion, and reduced sociability. PolyI:C offspring failed to display crossmodal and visual memory, and oddity preference was also impaired. Set-shifting, assessed with a lever-based operant conditioning task, was facilitated while touchscreen-based reversal learning was impaired. Correlations were found between maternal serum concentrations of CXCL1, acute maternal temperature and body weight changes, neonatal pup mass, and odd object discrimination and social behavior. Overall, while the offspring of polyI:C-treated rats displayed behavior abnormalities, maternal serum cytokines were not related to the long-term behavior changes in the offspring. Maternal sickness effects and neonatal pup size may be better indicators of later effects of maternal inflammation in the offspring.
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15
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Murty VP, DuBrow S, Davachi L. Decision-making Increases Episodic Memory via Postencoding Consolidation. J Cogn Neurosci 2018; 31:1308-1317. [PMID: 30063181 DOI: 10.1162/jocn_a_01321] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The ability for individuals to actively make decisions engages regions within the mesolimbic system and enhances memory for chosen items. In other behavioral contexts, mesolimbic engagement has been shown to enhance episodic memory by supporting consolidation. However, research has yet to investigate how consolidation may support interactions between decision-making and episodic memory. Across two studies, participants encoded items that were covered by occluder screens and could either actively decide which of two items to uncover or an item was preselected by the experimenter. In Study 1, we show that active decision-making reduces forgetting rates across an immediate and 24-hr memory test, a behavioral marker of consolidation. In Study 2, we use functional neuroimaging to characterize putative neural markers of memory consolidation by measuring interactions between the hippocampus and perirhinal cortex (PRC) during a postencoding period that reexposed participants to elements of the decision-making context without exposing them to memoranda. We show that choice-related striatal engagement is associated with increased postencoding hippocampal-PRC interactions. Finally, we show that a previous reported relationship between choice-related striatal engagement and long-term memory is accounted for by these postencoding hippocampal-PRC interactions. Together, these findings support a model by which actively deciding to encode information enhances memory consolidation to preserve episodic memory for outcomes, a process that may be facilitated by reexposure to the original decision-making context.
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16
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Bell AH, Bultitude JH. Methods matter: A primer on permanent and reversible interference techniques in animals for investigators of human neuropsychology. Neuropsychologia 2018; 115:211-219. [PMID: 28943365 PMCID: PMC6018620 DOI: 10.1016/j.neuropsychologia.2017.09.019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2017] [Revised: 09/07/2017] [Accepted: 09/19/2017] [Indexed: 12/05/2022]
Abstract
The study of patients with brain lesions has contributed greatly to our understanding of the biological bases of human cognition, but this approach also has several unavoidable limitations. Research that uses animal models complements and extends human neuropsychology by addressing many of these limitations. In this review, we provide an overview of permanent and reversible animal lesion techniques for researchers of human neuropsychology, with the aim of highlighting how these methods provide a valuable adjunct to behavioural, neuroimaging, physiological, and clinical investigations in humans. Research in animals has provided important lessons about how the limitations of one or more techniques, or differences in their mechanism of action, has impacted upon the understanding of brain organisation and function. These cautionary tales highlight the importance of striving for a thorough understanding of how any intereference technique works (whether in animal or human), and for how to best use animal research to clarify the precise mechanisms underlying temporary lesion methods in humans.
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Affiliation(s)
- Andrew H Bell
- MRC Cognition and Brain Sciences Unit, University of Cambridge, Cambridge, UK; Department of Experimental Psychology, University of Oxford, Oxford, UK.
| | - Janet H Bultitude
- Department of Psychology, University of Bath, Bath, UK; Centre for Pain Research, University of Bath, Bath, UK; The Centre for Functional Magnetic Resonance Imaging of the Brain, University of Oxford, Oxford, UK
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17
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Chen YH, Huang EYK, Kuo TT, Miller J, Chiang YH, Hoffer BJ. Impact of Traumatic Brain Injury on Dopaminergic Transmission. Cell Transplant 2018; 26:1156-1168. [PMID: 28933212 PMCID: PMC5657731 DOI: 10.1177/0963689717714105] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Brain trauma is often associated with severe morbidity and is a major public health concern. Even when injury is mild and no obvious anatomic disruption is seen, many individuals suffer disabling neuropsychological impairments such as memory loss, mood dysfunction, substance abuse, and adjustment disorder. These changes may be related to subtle disruption of neural circuits as well as functional changes at the neurotransmitter level. In particular, there is considerable evidence that dopamine (DA) physiology in the nigrostriatal and mesocorticolimbic pathways might be impaired after traumatic brain injury (TBI). Alterations in DA levels can lead to oxidative stress and cellular dysfunction, and DA plays an important role in central nervous system inflammation. Therapeutic targeting of DA pathways may offer benefits for both neuronal survival and functional outcome after TBI. The purpose of this review is to discuss the role of DA pathology in acute TBI and the potential impact of therapies that target these systems for the treatment of TBI.
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Affiliation(s)
- Yuan-Hao Chen
- Department of Neurological Surgery, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan, Republic of China
- Yuan-Hao Chen, Department of Neurological Surgery, Tri-Service General Hospital, National Defense Medical Center, 4F, No. 325, 2nd Sec., Cheng-Kung Road, Nei-Hu District, Taipei City, 114 Taiwan, Republic of China.
| | - Eagle Yi-Kung Huang
- Department of Pharmacology, National Defense Medical Center, Taipei, Taiwan, Republic of China
| | - Tung-Tai Kuo
- Graduate Institute of Computer and Communication Engineering, National Taipei University of Technology, Taipei, Taiwan, Republic of China
| | - Jonathan Miller
- Department of Neurosurgery, Case Western Reserve University School of Medicine, Cleveland, OH, USA
| | - Yung-Hsiao Chiang
- Section of Neurosurgery, Department of Surgery, Taipei Medical University Hospital, Taipei Medical University, Taipei, Taiwan, Republic of China
| | - Barry J. Hoffer
- Department of Neurosurgery, Case Western Reserve University School of Medicine, Cleveland, OH, USA
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18
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Morici JF, Miranda M, Gallo FT, Zanoni B, Bekinschtein P, Weisstaub NV. 5-HT2a receptor in mPFC influences context-guided reconsolidation of object memory in perirhinal cortex. eLife 2018; 7:33746. [PMID: 29717980 PMCID: PMC5931799 DOI: 10.7554/elife.33746] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 04/07/2018] [Indexed: 12/12/2022] Open
Abstract
Context-dependent memories may guide adaptive behavior relaying in previous experience while updating stored information through reconsolidation. Retrieval can be triggered by partial and shared cues. When the cue is presented, the most relevant memory should be updated. In a contextual version of the object recognition task, we examined the effect of medial PFC (mPFC) serotonin 2a receptor (5-HT2aR) blockade during retrieval in reconsolidation of competing objects memories. We found that mPFC 5-HT2aR controls retrieval and reconsolidation of object memories in the perirhinal cortex (PRH), but not in the dorsal hippocampus in rats. Also, reconsolidation of objects memories in PRH required a functional interaction between the ventral hippocampus and the mPFC. Our results indicate that in the presence of conflicting information at retrieval, mPFC 5-HT2aR may facilitate top-down context-guided control over PRH to control the behavioral response and object memory reconsolidation.
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Affiliation(s)
- Juan Facundo Morici
- Departamento de Ciencias Fisiológicas, Instituto de Fisiología y Biofísica Bernardo Houssay, Facultad de Medicina, Universidad de Buenos Aires, CONICET, Buenos Aires, Argentina.,Instituto de Neurociencia Cognitiva y Translacional, Universidad Favaloro, INECO, CONICET, Buenos Aires, Argentina
| | - Magdalena Miranda
- Instituto de Neurociencia Cognitiva y Translacional, Universidad Favaloro, INECO, CONICET, Buenos Aires, Argentina.,Instituto de Biologia Celular y Neurociencias, Universidad de Buenos Aires, CONICET, Buenos Aires, Argentina
| | - Francisco Tomás Gallo
- Instituto de Neurociencia Cognitiva y Translacional, Universidad Favaloro, INECO, CONICET, Buenos Aires, Argentina.,Instituto de Biologia Celular y Neurociencias, Universidad de Buenos Aires, CONICET, Buenos Aires, Argentina
| | - Belén Zanoni
- Instituto de Neurociencia Cognitiva y Translacional, Universidad Favaloro, INECO, CONICET, Buenos Aires, Argentina
| | - Pedro Bekinschtein
- Instituto de Neurociencia Cognitiva y Translacional, Universidad Favaloro, INECO, CONICET, Buenos Aires, Argentina.,Instituto de Biologia Celular y Neurociencias, Universidad de Buenos Aires, CONICET, Buenos Aires, Argentina
| | - Noelia V Weisstaub
- Departamento de Ciencias Fisiológicas, Instituto de Fisiología y Biofísica Bernardo Houssay, Facultad de Medicina, Universidad de Buenos Aires, CONICET, Buenos Aires, Argentina.,Instituto de Neurociencia Cognitiva y Translacional, Universidad Favaloro, INECO, CONICET, Buenos Aires, Argentina
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Bussey TJ, Saksida LM, Murray EA. The Perceptual-Mnemonic/Feature Conjunction Model of Perirhinal Cortex Function. ACTA ACUST UNITED AC 2018; 58:269-82. [PMID: 16194969 DOI: 10.1080/02724990544000004] [Citation(s) in RCA: 137] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The perirhinal cortex was once thought to be “silent cortex”, virtually ignored by researchers interested in the neurobiology of learning and memory. Following studies of brain damage associated with cases of amnesia, perirhinal cortex is now widely regarded as part of a “medial temporal lobe (MTL) memory system”. This system is thought to be more or less functionally homogeneous, having a special role in declarative memory, and making little or no contribution to other functions such as perception. In the present article, we summarize an alternative view. First, we propose that components of the putative MTL system such as the hippocampus and perirhinal cortex have distinct and dissociable functions. Second, we provide evidence that the perirhinal cortex has a role in visual discrimination. In addition, we propose a specific role for perirhinal cortex in visual discrimination: the contribution of complex conjunctive representations to the solution of visual discrimination problems with a high degree of “feature ambiguity”. These proposals constitute a new view of perirhinal cortex function, one that does not assume strict modularity of function in the occipito-temporal visual stream, but replaces this idea with the notion of a hierarchical representational continuum.
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Affiliation(s)
- Timothy J Bussey
- Department of Experimental Psychology, University of Cambridge, UK.
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20
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Lee ACH, Barense MD, Graham KS. The Contribution of the Human Medial Temporal Lobe to Perception: Bridging the Gap between Animal and Human Studies. ACTA ACUST UNITED AC 2018; 58:300-25. [PMID: 16194971 DOI: 10.1080/02724990444000168] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The medial temporal lobe (MTL) has been considered traditionally to subserve declarative memory processes only. Recent studies in nonhuman primates suggest, however, that the MTL may also be critical to higher order perceptual processes, with the hippocampus and perirhinal cortex being involved in scene and object perception, respectively. The current article reviews the human neuropsychological literature to determine whether there is any evidence to suggest that these same views may apply to the human MTL. Although the majority of existing studies report intact perception following MTL damage in human amnesics, there have been recent studies that suggest that when scene and object perception are assessed systematically, signifi-cant impairments in perception become apparent. These findings have important implications for current mnemonic theories of human MTL function and our understanding of human amnesia as a result of MTL lesions.
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Affiliation(s)
- Andy C H Lee
- MRC Cognition and Brain Sciences Unit, Cambridge, UK.
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21
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Graham KS, Gaffan D. The Role of the Medial Temporal Lobe in Memory and Perception: Evidence from Rats, Nonhuman Primates and Humans. ACTA ACUST UNITED AC 2018; 58:193-201. [PMID: 16194964 DOI: 10.1080/02724990544000059] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Kim S Graham
- MRC Cognition and Brain Sciences Unit, Cambridge, UK.
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22
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Bright P, Moss HE, Stamatakis EA, Tyler LK. The Anatomy of Object Processing: The Role of Anteromedial Temporal Cortex. ACTA ACUST UNITED AC 2018; 58:361-77. [PMID: 16194974 DOI: 10.1080/02724990544000013] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
How objects are represented and processed in the brain remains a key issue in cognitive neuroscience. We have developed a conceptual structure account in which category-specific semantic deficits emerge due to differences in the structure and content of concepts rather than from explicit divisions of conceptual knowledge in separate stores. The primary claim is that concepts associated with particular categories (e.g., animals, tools) differ in the number and type of properties and the extent to which these properties are correlated with each other. In this review, we describe recent neuropsychological and neuroimaging studies in which we have extended our theoretical account by incorporating recent claims about the neuroanatomical basis of feature integration and differentiation that arise from research into hierarchical object processing streams in nonhuman primates and humans. A clear picture has emerged in which the human perirhinal cortex and neighbouring anteromedial temporal structures appear to provide the neural infrastructure for making fine-grained discriminations among objects, suggesting that damage within the perirhinal cortex may underlie the emergence of category-specific semantic deficits in brain-damaged patients.
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Affiliation(s)
- Peter Bright
- Department of Experimental Psychology, University of Cambridge, UK.
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23
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Hampton RR. Monkey Perirhinal Cortex is Critical for Visual Memory, but not for Visual Perception: Reexamination of the Behavioural Evidence from Monkeys. ACTA ACUST UNITED AC 2018; 58:283-99. [PMID: 16194970 DOI: 10.1080/02724990444000195] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Overdependence on discrimination learning paradigms to assess the function of perirhinal cortex has complicated understanding of the cognitive role of this structure. Impairments in discrimination learning can result from at least two distinct causes: (a) failure to accurately apprehend and represent the relevant stimuli, or (b) failure to form and remember associations between stimulus representations and reward. Thus, the results of discrimination learning experiments do not readily differentiate deficits in perception from deficits in learning and memory. Here I describe studies that do dissociate learning and memory from perception and show that perirhinal cortex damage impairs learning and/or memory, but not perception. Reanalysis and reconsideration of other published data call into further question the hypothesis that the monkey perirhinal cortex plays a critical role in visual perception.
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Affiliation(s)
- Robert R Hampton
- Department of Psychology and Yerkes National Primate Research Center, Emory University, Atlanta, GA 30322, USA.
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24
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Jiang H, He NY, Sun YH, Jian FF, Bian LG, Shen JK, Yan FH, Pan SJ, Sun QF. Altered gray and white matter microstructure in Cushing’s disease: A diffusional kurtosis imaging study. Brain Res 2017; 1665:80-87. [DOI: 10.1016/j.brainres.2017.04.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Revised: 04/12/2017] [Accepted: 04/14/2017] [Indexed: 02/03/2023]
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25
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Zhang B. Consequences of early adverse rearing experience(EARE) on development: insights from non-human primate studies. Zool Res 2017; 38:7-35. [PMID: 28271667 PMCID: PMC5368383 DOI: 10.13918/j.issn.2095-8137.2017.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 12/30/2016] [Indexed: 12/18/2022] Open
Abstract
Early rearing experiences are important in one's whole life, whereas early adverse rearing experience(EARE) is usually related to various physical and mental disorders in later life. Although there were many studies on human and animals, regarding the effect of EARE on brain development, neuroendocrine systems, as well as the consequential mental disorders and behavioral abnormalities, the underlying mechanisms remain unclear. Due to the close genetic relationship and similarity in social organizations with humans, non-human primate(NHP) studies were performed for over 60 years. Various EARE models were developed to disrupt the early normal interactions between infants and mothers or peers. Those studies provided important insights of EARE induced effects on the physiological and behavioral systems of NHPs across life span, such as social behaviors(including disturbance behavior, social deficiency, sexual behavior, etc), learning and memory ability, brain structural and functional developments(including influences on neurons and glia cells, neuroendocrine systems, e.g., hypothalamic-pituitary-adrenal(HPA) axis, etc). In this review, the effects of EARE and the underlying epigenetic mechanisms were comprehensively summarized and the possibility of rehabilitation was discussed.
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Affiliation(s)
- Bo Zhang
- Yunnan Key Laboratory of Primate Biomedical Research, Kunming Yunnan 650500, China; Institute of Primate Translational Medicine, Kunming University of Science and Technology, Kunming Yunnan 650500, China; National Institute of Health, Bethesda, Maryland, USA.
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26
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Fu H, Hussaini SA, Wegmann S, Profaci C, Daniels JD, Herman M, Emrani S, Figueroa HY, Hyman BT, Davies P, Duff KE. 3D Visualization of the Temporal and Spatial Spread of Tau Pathology Reveals Extensive Sites of Tau Accumulation Associated with Neuronal Loss and Recognition Memory Deficit in Aged Tau Transgenic Mice. PLoS One 2016; 11:e0159463. [PMID: 27466814 PMCID: PMC4965059 DOI: 10.1371/journal.pone.0159463] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2015] [Accepted: 07/01/2016] [Indexed: 11/19/2022] Open
Abstract
3D volume imaging using iDISCO+ was applied to observe the spatial and temporal progression of tau pathology in deep structures of the brain of a mouse model that recapitulates the earliest stages of Alzheimer’s disease (AD). Tau pathology was compared at four timepoints, up to 34 months as it spread through the hippocampal formation and out into the neocortex along an anatomically connected route. Tau pathology was associated with significant gliosis. No evidence for uptake and accumulation of tau by glia was observed. Neuronal cells did appear to have internalized tau, including in extrahippocampal areas as a small proportion of cells that had accumulated human tau protein did not express detectible levels of human tau mRNA. At the oldest timepoint, mature tau pathology in the entorhinal cortex (EC) was associated with significant cell loss. As in human AD, mature tau pathology in the EC and the presence of tau pathology in the neocortex correlated with cognitive impairment. 3D volume imaging is an ideal technique to easily monitor the spread of pathology over time in models of disease progression.
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Affiliation(s)
- Hongjun Fu
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, New York, New York, United States of America
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, New York, United States of America
| | - S. Abid Hussaini
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, New York, New York, United States of America
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, New York, United States of America
| | - Susanne Wegmann
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts, United States of America
| | - Caterina Profaci
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, New York, New York, United States of America
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, New York, United States of America
| | - Jacob D. Daniels
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, New York, New York, United States of America
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, New York, United States of America
| | - Mathieu Herman
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, New York, New York, United States of America
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, New York, United States of America
| | - Sheina Emrani
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, New York, New York, United States of America
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, New York, United States of America
| | - Helen Y. Figueroa
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, New York, New York, United States of America
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, New York, United States of America
| | - Bradley T. Hyman
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts, United States of America
| | - Peter Davies
- Litwin-Zucker Center for Research in Alzheimer's Disease, Feinstein Institute for Medical Research, North Shore/LIJ Health System, Manhasset, New York, United States of America
| | - Karen E. Duff
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, New York, New York, United States of America
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, New York, United States of America
- * E-mail:
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Schallmo MP, Kassel MT, Weisenbach SL, Walker SJ, Guidotti-Breting LM, Rao JA, Hazlett KE, Considine CM, Sethi G, Vats N, Pecina M, Welsh RC, Starkman MN, Giordani B, Langenecker SA. A new semantic list learning task to probe functioning of the Papez circuit. J Clin Exp Neuropsychol 2016; 37:816-33. [PMID: 26313512 DOI: 10.1080/13803395.2015.1052732] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
INTRODUCTION List learning tasks are powerful clinical tools for studying memory, yet have been relatively underutilized within the functional imaging literature. This limits understanding of regions such as the Papez circuit that support memory performance in healthy, nondemented adults. METHOD The current study characterized list learning performance in 40 adults who completed a semantic list learning task (SLLT) with a Brown-Peterson manipulation during functional magnetic resonance imaging (fMRI). Cued recall with semantic cues and recognition memory were assessed after imaging. Internal reliability, convergent, and discriminant validity were evaluated. RESULTS Subjects averaged 38% accuracy in recall (62% for recognition), with primacy but no recency effects observed. Validity and reliability were demonstrated by showing that the SLLT was correlated with the California Verbal Learning Test (CVLT), but not with executive functioning tests, and by high intraclass correlation coefficient across lists for recall (.91). fMRI measurements during encoding (vs. silent rehearsal) revealed significant activation in bilateral hippocampus, parahippocampus, and bilateral anterior and posterior cingulate cortex. Post hoc analyses showed increased activation in anterior and middle hippocampus, subgenual cingulate, and mammillary bodies specific to encoding. In addition, increasing age was positively associated with increased activation in a diffuse network, particularly frontal cortex and specific Papez regions for correctly recalled words. Gender differences were specific to left inferior and superior frontal cortex. CONCLUSIONS This is a clinically relevant list learning task that can be used in studies of groups for which the Papez circuit is damaged or disrupted, in mixed or crossover studies at imaging and clinical sites.
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Ramos JMJ. Perirhinal cortex supports tactual discrimination tasks with increasing levels of complexity: Retrograde effect. Neurobiol Learn Mem 2016; 131:121-30. [PMID: 27021016 DOI: 10.1016/j.nlm.2016.03.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Revised: 03/19/2016] [Accepted: 03/25/2016] [Indexed: 10/22/2022]
Abstract
Recent studies have suggested that the perirhinal cortex (Prh) supports representations of feature conjunctions in the visual modality during the acquisition/encoding of complex discriminations. To extend this idea to other sensory modalities and to another stage of the discrimination process, we studied the effect of Prh lesions on the expression of a series of tactual discrimination tasks learned preoperatively. These tasks differed from one another in the degree of feature overlap of the stimuli and in the difficulty of the task. During pre- and post-operative testing phases, rats had to discriminate among 3 stimuli simultaneously exposed in 3 arms of a 4-arm plus-shaped maze. Prh-damaged rats showed a profound impairment in the expression of tactual discrimination tasks when the stimuli had a high or intermediate degree of feature ambiguity, but not when they had a low degree of ambiguity (experiments 1a-1c). In order to experimentally dissociate between subregions within the medial temporal lobe, experiment 2 was conducted to show that hippocampal lesions did not cause any impairment in task expression even when the stimuli had a high degree of feature ambiguity. When the tactual discrimination tasks used simple/individual nonoverlapping features of the stimuli (size), Prh lesions did not affect the expression of these discriminations despite the high level of difficulty of these tasks (experiments 3a and 3b). These findings suggest that, in the somatosensory modality, the Prh plays an essential role in the processing of complex stimuli with overlapping features but not in simple tactual discriminations. Furthermore, the Prh is necessary not just during acquisition but also during expression/performance of the discrimination task.
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Affiliation(s)
- Juan M J Ramos
- Department of Psychobiology, University of Granada, Granada 18071, Spain; Mind, Brain and Behavior Research Center (CIMCYC), University of Granada, Granada 18071, Spain.
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Neural representation for object recognition in inferotemporal cortex. Curr Opin Neurobiol 2016; 37:23-35. [PMID: 26771242 DOI: 10.1016/j.conb.2015.12.001] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Accepted: 12/01/2015] [Indexed: 11/22/2022]
Abstract
We suggest that population representation of objects in inferotemporal cortex lie on a continuum between a purely structural, parts-based description and a purely holistic description. The intrinsic dimensionality of object representation is estimated to be around 100, perhaps with lower dimensionalities for object representations more toward the holistic end of the spectrum. Cognitive knowledge in the form of semantic information and task information feed back to inferotemporal cortex from perirhinal and prefrontal cortex respectively, providing high-level multimodal-based expectations that assist in the interpretation of object stimuli. Integration of object information across eye movements may also contribute to object recognition through a process of active vision.
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30
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Jeong W, Chung CK, Kim JS. Episodic memory in aspects of large-scale brain networks. Front Hum Neurosci 2015; 9:454. [PMID: 26321939 PMCID: PMC4536379 DOI: 10.3389/fnhum.2015.00454] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Accepted: 07/31/2015] [Indexed: 12/28/2022] Open
Abstract
Understanding human episodic memory in aspects of large-scale brain networks has become one of the central themes in neuroscience over the last decade. Traditionally, episodic memory was regarded as mostly relying on medial temporal lobe (MTL) structures. However, recent studies have suggested involvement of more widely distributed cortical network and the importance of its interactive roles in the memory process. Both direct and indirect neuro-modulations of the memory network have been tried in experimental treatments of memory disorders. In this review, we focus on the functional organization of the MTL and other neocortical areas in episodic memory. Task-related neuroimaging studies together with lesion studies suggested that specific sub-regions of the MTL are responsible for specific components of memory. However, recent studies have emphasized that connectivity within MTL structures and even their network dynamics with other cortical areas are essential in the memory process. Resting-state functional network studies also have revealed that memory function is subserved by not only the MTL system but also a distributed network, particularly the default-mode network (DMN). Furthermore, researchers have begun to investigate memory networks throughout the entire brain not restricted to the specific resting-state network (RSN). Altered patterns of functional connectivity (FC) among distributed brain regions were observed in patients with memory impairments. Recently, studies have shown that brain stimulation may impact memory through modulating functional networks, carrying future implications of a novel interventional therapy for memory impairment.
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Affiliation(s)
- Woorim Jeong
- Department of Neurosurgery, Seoul National University Hospital Seoul, South Korea ; Interdisciplinary Program in Neuroscience, Seoul National University College of Natural Science Seoul, South Korea
| | - Chun Kee Chung
- Department of Neurosurgery, Seoul National University Hospital Seoul, South Korea ; Interdisciplinary Program in Neuroscience, Seoul National University College of Natural Science Seoul, South Korea ; Neuroscience Research Institute, Seoul National University Medical Research Center Seoul, South Korea ; Department of Brain and Cognitive Sciences, Seoul National University College of Natural Sciences Seoul, South Korea
| | - June Sic Kim
- Department of Brain and Cognitive Sciences, Seoul National University College of Natural Sciences Seoul, South Korea
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Stiver ML, Jacklin DL, Mitchnick KA, Vicic N, Carlin J, O'Hara M, Winters BD. Cholinergic manipulations bidirectionally regulate object memory destabilization. Learn Mem 2015; 22:203-14. [PMID: 25776038 PMCID: PMC4371172 DOI: 10.1101/lm.037713.114] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Accepted: 12/22/2014] [Indexed: 11/25/2022]
Abstract
Consolidated memories can become destabilized and open to modification upon retrieval. Destabilization is most reliably prompted when novel information is present during memory reactivation. We hypothesized that the neurotransmitter acetylcholine (ACh) plays an important role in novelty-induced memory destabilization because of its established involvement in new learning. Accordingly, we investigated the effects of cholinergic manipulations in rats using an object recognition paradigm that requires reactivation novelty to destabilize object memories. The muscarinic receptor antagonist scopolamine, systemically or infused directly into the perirhinal cortex, blocked this novelty-induced memory destabilization. Conversely, systemic oxotremorine or carbachol, muscarinic receptor agonists, administered systemically or intraperirhinally, respectively, mimicked the destabilizing effect of novel information during reactivation. These bidirectional effects suggest a crucial influence of ACh on memory destabilization and the updating functions of reconsolidation. This is a hitherto unappreciated mnemonic role for ACh with implications for its potential involvement in cognitive flexibility and the dynamic process of long-term memory storage.
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Affiliation(s)
- Mikaela L Stiver
- Department of Psychology and Neuroscience Program, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Derek L Jacklin
- Department of Psychology and Neuroscience Program, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Krista A Mitchnick
- Department of Psychology and Neuroscience Program, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Nevena Vicic
- Department of Psychology and Neuroscience Program, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Justine Carlin
- Department of Psychology and Neuroscience Program, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Matthew O'Hara
- Department of Psychology and Neuroscience Program, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Boyer D Winters
- Department of Psychology and Neuroscience Program, University of Guelph, Guelph, Ontario N1G 2W1, Canada
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Chase HW, Clos M, Dibble S, Fox P, Grace AA, Phillips ML, Eickhoff SB. Evidence for an anterior-posterior differentiation in the human hippocampal formation revealed by meta-analytic parcellation of fMRI coordinate maps: focus on the subiculum. Neuroimage 2015; 113:44-60. [PMID: 25776219 DOI: 10.1016/j.neuroimage.2015.02.069] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2014] [Revised: 12/17/2014] [Accepted: 02/25/2015] [Indexed: 02/05/2023] Open
Abstract
Previous studies, predominantly in experimental animals, have suggested the presence of a differentiation of function across the hippocampal formation. In rodents, ventral regions are thought to be involved in emotional behavior while dorsal regions mediate cognitive or spatial processes. Using a combination of modeling the co-occurrence of significant activations across thousands of neuroimaging experiments and subsequent data-driven clustering of these data we were able to provide evidence of distinct subregions within a region corresponding to the human subiculum, a critical hub within the hippocampal formation. This connectivity-based model consists of a bilateral anterior region, as well as separate posterior and intermediate regions on each hemisphere. Functional connectivity assessed both by meta-analytic and resting fMRI approaches revealed that more anterior regions were more strongly connected to the default mode network, and more posterior regions were more strongly connected to 'task positive' regions. In addition, our analysis revealed that the anterior subregion was functionally connected to the ventral striatum, midbrain and amygdala, a circuit that is central to models of stress and motivated behavior. Analysis of a behavioral taxonomy provided evidence for a role for each subregion in mnemonic processing, as well as implication of the anterior subregion in emotional and visual processing and the right posterior subregion in reward processing. These findings lend support to models which posit anterior-posterior differentiation of function within the human hippocampal formation and complement other early steps toward a comparative (cross-species) model of the region.
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Affiliation(s)
- Henry W Chase
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
| | - Mareike Clos
- Institute of Neuroscience and Medicine (INM-1), Research Center Jülich, Germany; Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Germany
| | - Sofia Dibble
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA, USA
| | - Peter Fox
- Research Imaging Center, University of Texas Health Science Center San Antonio, San Antonio, TX, USA; South Texas Veterans Administration Medical Center, San Antonio, TX, USA
| | - Anthony A Grace
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA; Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA, USA; Department of Psychology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Mary L Phillips
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Simon B Eickhoff
- Institute of Neuroscience and Medicine (INM-1), Research Center Jülich, Germany; Institute of Clinical Neuroscience and Medical Psychology, Heinrich-Heine University Düsseldorf, Germany
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Languille S, Liévin-Bazin A, Picq JL, Louis C, Dix S, De Barry J, Blin O, Richardson J, Bordet R, Schenker E, Djelti F, Aujard F. Deficits of psychomotor and mnesic functions across aging in mouse lemur primates. Front Behav Neurosci 2015; 8:446. [PMID: 25620921 PMCID: PMC4288241 DOI: 10.3389/fnbeh.2014.00446] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Accepted: 12/10/2014] [Indexed: 11/23/2022] Open
Abstract
Owing to a similar cerebral neuro-anatomy, non-human primates are viewed as the most valid models for understanding cognitive deficits. This study evaluated psychomotor and mnesic functions of 41 young to old mouse lemurs (Microcebus murinus). Psychomotor capacities and anxiety-related behaviors decreased abruptly from middle to late adulthood. However, mnesic functions were not affected in the same way with increasing age. While results of the spontaneous alternation task point to a progressive and widespread age-related decline of spatial working memory, both spatial reference and novel object recognition (NOR) memory tasks did not reveal any tendency due to large inter-individual variability in the middle-aged and old animals. Indeed, some of the aged animals performed as well as younger ones, whereas some others had bad performances in the Barnes maze and in the object recognition test. Hierarchical cluster analysis revealed that declarative-like memory was strongly impaired only in 7 out of 25 middle-aged/old animals. These results suggest that this analysis allows to distinguish elder populations of good and bad performers in this non-human primate model and to closely compare this to human aging.
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Affiliation(s)
- Solène Languille
- UMR 7179, Centre National de la Recherche Scientifique, Muséum National d'Histoire Naturelle France Brunoy, France
| | - Agatha Liévin-Bazin
- UMR 7179, Centre National de la Recherche Scientifique, Muséum National d'Histoire Naturelle France Brunoy, France
| | - Jean-Luc Picq
- UMR 7179, Centre National de la Recherche Scientifique, Muséum National d'Histoire Naturelle France Brunoy, France ; Laboratoire de Psychopathologie et de Neuropsychologie, EA 2027, Université Paris 8 St-Denis, France
| | - Caroline Louis
- Institut de Recherches Servier Croissy-sur-Seine, France
| | | | - Jean De Barry
- INCI UPR3212 CNRS et Innovative Health Diagnostics Strasbourg, France
| | - Olivier Blin
- Centre de Pharmacologie Clinique et d'Evaluations Thérapeutiques-CIC, Timone CNRS-INT-Aix Marseille Université Marseille, France
| | - Jill Richardson
- GlaxoSmithKline, R&D China U.K. Group Stevenage Stevenage, UK
| | - Régis Bordet
- Département de Pharmacologie Médicale, EA 1046, Université Lille Nord de France, UDSL, Faculté de Médecine CHU, Lille, France
| | | | - Fathia Djelti
- UMR 7179, Centre National de la Recherche Scientifique, Muséum National d'Histoire Naturelle France Brunoy, France
| | - Fabienne Aujard
- UMR 7179, Centre National de la Recherche Scientifique, Muséum National d'Histoire Naturelle France Brunoy, France
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Involvement of the human medial temporal lobe in a visual discrimination task. Behav Brain Res 2014; 268:22-30. [DOI: 10.1016/j.bbr.2014.03.030] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Revised: 03/14/2014] [Accepted: 03/17/2014] [Indexed: 11/21/2022]
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Rolls ET. Limbic systems for emotion and for memory, but no single limbic system. Cortex 2013; 62:119-57. [PMID: 24439664 DOI: 10.1016/j.cortex.2013.12.005] [Citation(s) in RCA: 198] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2013] [Revised: 12/05/2013] [Accepted: 12/13/2013] [Indexed: 12/28/2022]
Abstract
The concept of a (single) limbic system is shown to be outmoded. Instead, anatomical, neurophysiological, functional neuroimaging, and neuropsychological evidence is described that anterior limbic and related structures including the orbitofrontal cortex and amygdala are involved in emotion, reward valuation, and reward-related decision-making (but not memory), with the value representations transmitted to the anterior cingulate cortex for action-outcome learning. In this 'emotion limbic system' a computational principle is that feedforward pattern association networks learn associations from visual, olfactory and auditory stimuli, to primary reinforcers such as taste, touch, and pain. In primates including humans this learning can be very rapid and rule-based, with the orbitofrontal cortex overshadowing the amygdala in this learning important for social and emotional behaviour. Complementary evidence is described showing that the hippocampus and limbic structures to which it is connected including the posterior cingulate cortex and the fornix-mammillary body-anterior thalamus-posterior cingulate circuit are involved in episodic or event memory, but not emotion. This 'hippocampal system' receives information from neocortical areas about spatial location, and objects, and can rapidly associate this information together by the different computational principle of autoassociation in the CA3 region of the hippocampus involving feedback. The system can later recall the whole of this information in the CA3 region from any component, a feedback process, and can recall the information back to neocortical areas, again a feedback (to neocortex) recall process. Emotion can enter this memory system from the orbitofrontal cortex etc., and be recalled back to the orbitofrontal cortex etc. during memory recall, but the emotional and hippocampal networks or 'limbic systems' operate by different computational principles, and operate independently of each other except insofar as an emotional state or reward value attribute may be part of an episodic memory.
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Affiliation(s)
- Edmund T Rolls
- Oxford Centre for Computational Neuroscience, Oxford, UK; University of Warwick, Department of Computer Science, Coventry, UK.
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36
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Barker GRI, Warburton EC. Object-in-place associative recognition memory depends on glutamate receptor neurotransmission within two defined hippocampal-cortical circuits: a critical role for AMPA and NMDA receptors in the hippocampus, perirhinal, and prefrontal cortices. ACTA ACUST UNITED AC 2013; 25:472-81. [PMID: 24035904 PMCID: PMC4380082 DOI: 10.1093/cercor/bht245] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Object-in-place associative recognition memory depends on an interaction between the hippocampus (HPC), perirhinal (PRH), and medial prefrontal (mPFC) cortices, yet the contribution of glutamate receptor neurotransmission to these interactions is unknown. NMDA receptors (NMDAR) in the HPC were critical for encoding of object-in-place memory but not for single-item object recognition. Next, a disconnection procedure was used to examine the importance of “concurrent” glutamate neurotransmission in the HPC-mPFC and HPC-PRH. Contralateral unilateral infusions of NBQX (AMPAR antagonist), into the HPC-mPFC, or HPC-PRH, either before acquisition or test, impaired object-in-place performance. Thus, both circuits are necessary for encoding and retrieval. Crossed unilateral AP5 (NMDAR antagonist) infusions into the HPC-mPFC or HPC-PRH impaired encoding, but not retrieval. Specifically crossed HPC-mPFC infusions impaired both short-term (5 min) and longer term (1 h) memory while HPC-PRH infusions impaired longer term memory only. This delay-dependent effect of AP5 in the HPC-PRH on object-in-place memory, accords with its effects in the PRH, on single item object recognition memory, thereby suggesting that a single PRH synaptic plasticity mechanism underpins different recognition memory processes. Further, blocking excitatory neurotransmission in any pair of structures within the networks impaired “both” encoding and retrieval, thus object-in-place memory clearly requires network interdependency across multiple structures.
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Affiliation(s)
- Gareth Robert Issac Barker
- MRC Centre for Synaptic Plasticity, School of Physiology and Pharmacology, University of Bristol, Medical Sciences Building, University Walk, Bristol BS8 1TD, UK
| | - Elizabeth Clea Warburton
- MRC Centre for Synaptic Plasticity, School of Physiology and Pharmacology, University of Bristol, Medical Sciences Building, University Walk, Bristol BS8 1TD, UK
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37
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Daulatzai MA. Neurotoxic Saboteurs: Straws that Break the Hippo’s (Hippocampus) Back Drive Cognitive Impairment and Alzheimer’s Disease. Neurotox Res 2013; 24:407-59. [DOI: 10.1007/s12640-013-9407-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 06/06/2013] [Accepted: 06/17/2013] [Indexed: 12/29/2022]
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Urner M, Schwarzkopf DS, Friston K, Rees G. Early visual learning induces long-lasting connectivity changes during rest in the human brain. Neuroimage 2013; 77:148-56. [PMID: 23558105 PMCID: PMC3682182 DOI: 10.1016/j.neuroimage.2013.03.050] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Revised: 03/15/2013] [Accepted: 03/18/2013] [Indexed: 01/01/2023] Open
Abstract
Spontaneous fluctuations in resting state activity can change in response to experience-dependent plasticity and learning. Visual learning is fast and can be elicited in an MRI scanner. Here, we showed that a random dot motion coherence task can be learned within one training session. While the task activated primarily visual and parietal brain areas, learning related changes in neural activity were observed in the hippocampus. Crucially, even this rapid learning affected resting state dynamics both immediately after the learning and 24 h later. Specifically, the hippocampus changed its coupling with the striatum, in a way that was best explained as a consolidation of early learning related changes. Our findings suggest that long-lasting changes in neuronal coupling are accompanied by changes in resting state activity. Early learning of sensory task changes hippocampal activity. Coupling changes between hippocampus and striatum. Resting-state changes are consolidated during sleep. Stochastic DCM is a tool for resting state analysis.
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Affiliation(s)
- Maren Urner
- UCL Institute of Cognitive Neuroscience, University College London, UK.
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39
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Vivar C, van Praag H. Functional circuits of new neurons in the dentate gyrus. Front Neural Circuits 2013; 7:15. [PMID: 23443839 PMCID: PMC3580993 DOI: 10.3389/fncir.2013.00015] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Accepted: 01/23/2013] [Indexed: 01/17/2023] Open
Abstract
The hippocampus is crucial for memory formation. New neurons are added throughout life to the hippocampal dentate gyrus (DG), a brain area considered important for differential storage of similar experiences and contexts. To better understand the functional contribution of adult neurogenesis to pattern separation processes, we recently used a novel synapse specific trans-neuronal tracing approach to identify the (sub) cortical inputs to new dentate granule cells (GCs). It was observed that newly born neurons receive sequential innervation from structures important for memory function. Initially, septal-hippocampal cells provide input to new neurons, including transient innervation from mature GCs as well as direct feedback from area CA3 pyramidal neurons. After about 1 month perirhinal (PRH) and lateral entorhinal cortex (LEC), brain areas deemed relevant to integration of novel sensory and environmental information, become substantial input to new GCs. Here, we review the developmental time-course and proposed functional relevance of new neurons, within the context of their unique neural circuitry.
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Affiliation(s)
- Carmen Vivar
- Neuroplasticity and Behavior Unit, Laboratory of Neurosciences, Intramural Research Program, National Institute on Aging, National Institutes of Health Baltimore, MD, USA
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40
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Burke SN, Ryan L, Barnes CA. Characterizing cognitive aging of recognition memory and related processes in animal models and in humans. Front Aging Neurosci 2012; 4:15. [PMID: 22988437 PMCID: PMC3439640 DOI: 10.3389/fnagi.2012.00015] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2012] [Accepted: 06/05/2012] [Indexed: 11/13/2022] Open
Abstract
Analyses of complex behaviors across the lifespan of animals can reveal the brain regions that are impacted by the normal aging process, thereby, elucidating potential therapeutic targets. Recent data from rats, monkeys, and humans converge, all indicating that recognition memory and complex visual perception are impaired in advanced age. These cognitive processes are also disrupted in animals with lesions of the perirhinal cortex, indicating that the the functional integrity of this structure is disrupted in old age. This current review summarizes these data, and highlights current methodologies for assessing perirhinal cortex-dependent behaviors across the lifespan.
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Affiliation(s)
- Sara N Burke
- Evelyn F. McKnight Brain Institute, University of Arizona Tucson, AZ, USA ; Memory and Aging, ARL Division of Neural Systems, University of Arizona Tucson, AZ, USA
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41
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Vedder LC, Smith CC, Flannigan AE, McMahon LL. Estradiol-induced increase in novel object recognition requires hippocampal NR2B-containing NMDA receptors. Hippocampus 2012; 23:108-15. [PMID: 22965452 DOI: 10.1002/hipo.22068] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/30/2012] [Indexed: 11/11/2022]
Abstract
17β-estradiol (E2), at high circulating levels, enhances learning and memory in many women, making it a clinical treatment for hormone-related cognitive decline in aging. However, the mechanisms stimulated by E2, which are responsible for its cognitive enhancing effects, remain incompletely defined. Using an ovariectomized rat model, we previously reported that increasing plasma E2 enhances the magnitude of long-term potentiation (LTP) at hippocampal CA3-CA1 synapses, which is caused by a selective increase in current mediated by NR2B-containing NMDARs, leading to an increase in the NMDAR/AMPAR ratio. Whether the increase in NR2B current is causally related to the ability of E2 to enhance hippocampal dependent learning and memory has yet to be tested. Here, we find that E2 enhances performance in the novel object recognition (NOR) task with the same time course we previously showed E2 enhances the LTP magnitude, temporally linking the increase in LTP to enhanced learning and memory. Furthermore, using the selective NR2B subunit antagonist Ro25-6981, we find that the E2-enhanced NOR, like the enhanced LTP, requires hippocampal NR2B-containing NMDARs, specifically in area CA1. Finally, using whole-cell recordings and the phosphatase inhibitor orthovanadate, we investigated whether the E2-induced increase in NMDAR current is caused by an increase in the density of synaptic NMDARs and/or an increase in NMDAR subunit phosphorylation. We find that both mechanisms are responsible for the enhanced NMDAR current in E2-treated rats. Our results show that the E2-enhanced NOR requires a functional increase in NR2B-containing NMDARs, a requirement shared with the E2-enhanced LTP magnitude at CA3-CA1 synapses, supporting the hypothesis that the increase in LTP likely contributes to the enhanced learning and memory following an increase in plasma E2 levels.
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Affiliation(s)
- Lindsey C Vedder
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
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Dopamine-glutamate interplay in the ventral striatum modulates spatial learning in a receptor subtype-dependent manner. Neuropsychopharmacology 2012; 37:1122-33. [PMID: 22218092 PMCID: PMC3306874 DOI: 10.1038/npp.2011.296] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The ventral striatum (VS) is characterized by a distinctive neural architecture in which multiple corticolimbic glutamatergic (GLUergic) and mesolimbic dopaminergic (DAergic) afferents converge on the same output cell type (the medium-sized spiny neuron, MSN). However, despite the gateway function attributed to VS and its involvement in action selection and spatial navigation, as well as the evidence of physical and functional receptor-receptor interaction between different members of ionotropic GLUergic and DAergic receptors, there is no available knowledge that such reciprocal interaction may be critical in shaping the ability to learn novel spatial and non-spatial arrangement of stimuli. In this study, it was evaluated whether intra-VS bilateral infusion of either N-methyl-D-aspartate (NMDA) or α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor-selective antagonists may suppress the ability to detect spatial or non-spatial novelty in a non-associative behavioral task. In a second set of experiments, we further examined the hypothesis that VS-mediated spatial information processing may be subserved by some preferential receptor-receptor interactions among specific GLUergic and DAergic receptor subtypes. This was assessed by concomitant intra-VS infusion of the combination between subthreshold doses of either NMDA or AMPA receptor antagonists with individual D1 or D2 receptor blockade. The results of this study highlighted the fact that NMDA or AMPA receptors are differentially involved in processing of spatial and non-spatial novelty, and showed for the first time that preferential NMDA/D1 and AMPA/D2 receptor-receptor functional communication, but not NMDA/D2 and AMPA/D1, is required for enabling learning of novel spatial information in the VS.
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Loiselle M, Rouleau I, Nguyen DK, Dubeau F, Macoir J, Whatmough C, Lepore F, Joubert S. Comprehension of concrete and abstract words in patients with selective anterior temporal lobe resection and in patients with selective amygdalo-hippocampectomy. Neuropsychologia 2012; 50:630-9. [PMID: 22245005 DOI: 10.1016/j.neuropsychologia.2011.12.023] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2011] [Revised: 12/28/2011] [Accepted: 12/31/2011] [Indexed: 10/14/2022]
Abstract
The role of the anterior temporal lobe (ATL) in semantic memory is now firmly established. There is still controversy, however, regarding the specific role of this region in processing various types of concepts. There have been reports of patients suffering from semantic dementia (SD), a neurodegenerative condition in which the ATL is damaged bilaterally, who present with greater semantic impairment for concrete concepts than for abstract concepts, an effect known as reversal of the concreteness effect. This effect has previously been interpreted as reflecting degraded visual-perceptual features of objects due to damage to the inferior temporal lobes such as is observed in SD. Temporal lobe atrophy in SD, however, is bilateral even if it usually predominates to the left ATL, and it has been found to extend beyond the ATL, throughout the temporal lobes including medial and posterior temporal lobe regions. The question therefore remains whether greater impairment for concrete concepts results from damage to the ATL or from damage to the visual association cortex, and if unilateral damage can produce such a deficit. The aim of the present study was to investigate the processing of concrete and abstract words in rare patients who underwent a selective ATL surgical resection, and to compare their performance with that of patients with selective medial temporal lobe damage sparing the ATL region. Seven patients with a selective unilateral anterior temporal resection (ATL), 15 patients with a selective unilateral amygdalo-hippocampectomy (SeAH), and 15 healthy age- and education-matched controls underwent detailed neuropsychological assessment and carried out a semantic similarity judgment task evaluating their comprehension of concrete and abstract words. Results showed that both ATL and SeAH groups were significantly impaired on the semantic task relative to the control group. Within the patient groups, however, comprehension of concrete words was significantly more impaired than that of abstract words in the ATL group, while comprehension of abstract and concrete words was equally affected in the SeAH group. Results of this study suggest that the ATL region may play a critical role in processing concrete concepts, and that the reversal of the concreteness effect observed in ATL patients may result from damage to a categorical organization underlying the representation of concrete concepts.
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Haase L, Wang M, Green E, Murphy C. Functional connectivity during recognition memory in individuals genetically at risk for Alzheimer's disease. Hum Brain Mapp 2011; 34:530-42. [PMID: 22102296 DOI: 10.1002/hbm.21451] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2011] [Revised: 07/03/2011] [Accepted: 08/08/2011] [Indexed: 11/10/2022] Open
Abstract
The medial temporal lobes (MTL) and frontal cortex have been shown to subserve memory processes. Neurodegenerative diseases, such as Alzheimer's disease (AD), disrupt the neuronal networks that underlie memory processing. The ε4 allele of the apolipoprotein E gene is a genetic risk factor for AD and is associated with decrements in memory and in olfactory function. The present study utilized EQS, a structural equation modeling software program, to examine differences in the neuronal networks between non-demented ε4 carriers and ε4 noncarriers during a cross-modal olfactory recognition memory paradigm. Prior to fMRI scanning, participants were presented with 16 odors. During two scans, participants discriminated between names of odors presented before scanning (targets) or not presented (foils). The results indicate significant connections between bilateral frontal lobes and MTL for ε4 carriers when they misidentified a foil as a target. When ε4 noncarriers correctly identified a target, there were greater associations between the amygdala, MTL, and right frontal lobe; these associations also modeled the brain's response when ε4 noncarriers misidentified a foil as a target. During memory retrieval, affective cues may facilitate retrieval in ε4 noncarriers relative to ε4 carriers. Last, no model was found that best represented the functional network used by ε4 carriers when they correctly identified a target, which may reflect variability of neuronal recruitment within this population.
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Affiliation(s)
- Lori Haase
- Joint Doctoral Program in Clinical Psychology, San Diego State University/University of California San Diego, San Diego, CA, USA
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Young JA. Pharmacotherapy for traumatic brain injury: focus on sympathomimetics. Pharmacol Ther 2011; 134:1-7. [PMID: 21893094 DOI: 10.1016/j.pharmthera.2011.08.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2011] [Accepted: 08/02/2011] [Indexed: 12/31/2022]
Abstract
Traumatic brain injury (TBI) is a devastating neurological injury with broad manifestations. Unfortunately, its diagnosis and efficacious treatments remain elusive. Different post injury symptoms are exhibited at different time frames, indicative of a time-related progression of the pathology. Therefore, particular treatments must be tailored to the post injury time frame. This overview is focused on the secondary chronic phase following TBI and the value of sympathomimetic therapy during this phase. The various direct- and indirect-acting drugs are reviewed, and the treatment protocol employed by the author is described.
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Affiliation(s)
- James A Young
- Rush University, Rehab Associates of Chicago, 1725 W. Harrison St., Chicago, IL 60612, USA.
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Kealy J, Commins S. The rat perirhinal cortex: A review of anatomy, physiology, plasticity, and function. Prog Neurobiol 2011; 93:522-48. [DOI: 10.1016/j.pneurobio.2011.03.002] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2010] [Revised: 01/28/2011] [Accepted: 03/10/2011] [Indexed: 11/26/2022]
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Ding SL, Van Hoesen GW. Borders, extent, and topography of human perirhinal cortex as revealed using multiple modern neuroanatomical and pathological markers. Hum Brain Mapp 2011; 31:1359-79. [PMID: 20082329 DOI: 10.1002/hbm.20940] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Despite rapidly increasing interests in specific contributions of different components of human medial temporal lobe (MTL) to memory and memory impairments in normal aging and in many abnormal conditions such as Alzheimer's disease and Pick's disease, few modern neuroanatomical studies are available about the borders, extent, and topography of human perirhinal areas 35 and 36, which are important components of the MTL memory system. By a combined use of several cellular, neurochemical, and pathological markers, which mainly include neuronal nuclear antigen, calcium-binding proteins (parvalbumin and calbindin-D28k), nonphosphorylated neurofilament protein (SMI-32), Wisteria floribunda agglutinin, and abnormally phosphorylated tau (AT8), this study has revealed that the borders of human perirhinal areas 35 and 36 are significantly different from those defined with conventional Nissl staining. In general, areas 35 and 36 occupy the ventromedial temporopolar and rhinal sulcal regions, the collateral sulcal region, and the anterior two-thirds of fusiform gyrus or occipitotemporal gyrus. Furthermore, the precise borders, extent, and topography of human areas 35 and 36 and adjoining entorhinal cortex were marked at different anteroposterior levels of the MTL with reference to variations of rhinal and collateral sulci and other useful landmarks. These findings would provide reliable neuroanatomical base for the great and yet rapidly increasing number of neuroimaging studies of the human MTL structures in healthy and many abnormal conditions.
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Affiliation(s)
- Song-Lin Ding
- Department of Anatomy and Cell Biology, University of Iowa College of Medicine, Iowa City, Iowa, USA.
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Abstract
The proposal that a system centering on the perirhinal cortex is responsible for familiarity discrimination, particularly for single items, whereas a system centering on the hippocampus is responsible for recollective and more complex associational aspects of recognition memory is reviewed in the light of recent findings. In particular, the proposal is reviewed in relation to recent animal work with rats and results from human clinical studies. Notably, progress has been made in determining potential neural memory substrate mechanisms within the perirhinal cortex in rats. Recent findings have emphasized the importance of specifying the type of material, the type of test, and the strategy used by subjects to solve recognition memory tests if substrates are to be accurately inferred. It is to be expected that the default condition is that both the hippocampal and perirhinal systems will contribute to recognition memory performance. Indeed, rat lesion experiments provide examples of where cooperation between both systems is essential. Nevertheless, there remain examples of the independent operation of the hippocampal and perirhinal systems. Overall, it is concluded that most, though not all, of the recent findings are in support of the proposal. However, there is also evidence that the systems involved in recognition memory need to include structures outside the medial temporal lobe: there are significant but as yet only partially defined roles for the prefrontal cortex and sensory association cortices in recognition memory processes.
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Affiliation(s)
- Malcolm W Brown
- MRC Centre for Synaptic Plasticity, Department of Anatomy, Medical School, Bristol BS81TD, United Kingdom.
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The effects of acute treatment with escitalopram on the different stages of contextual fear conditioning are reversed by atomoxetine. Psychopharmacology (Berl) 2010; 212:131-43. [PMID: 20676614 DOI: 10.1007/s00213-010-1917-5] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2009] [Accepted: 06/12/2010] [Indexed: 12/24/2022]
Abstract
RATIONALE Although the antidepressant and anxiolytic effects of selective serotonin reuptake inhibitors and serotonin-noradrenaline reuptake inhibitors are well-documented, less is known about their cognitive effects. OBJECTIVE Escitalopram, a selective serotonin reuptake inhibitor, and atomoxetine, a selective noradrenaline reuptake inhibitor, were used to evaluate the interaction between noradrenergic and serotonergic neurotransmission in the modulation of contextual fear conditioning in rats. METHODS Contextual fear-conditioning test was used to investigate the acute effects of escitalopram, alone or in combination with atomoxetine, in different stages of learning and memory in rats. Furthermore, microdialysis in freely moving animals was used to investigate the effect of escitalopram on serotonin, dopamine, and noradrenaline levels in the rat hippocampus. RESULTS Escitalopram significantly increased conditioned responses when applied before the acquisition, but decreased responses, when applied before the recall test. When administered during memory consolidation, escitalopram dose-dependently enhanced conditioned responding. These effects were blocked by atomoxetine. Escitalopram (at a dose that affects memory consolidation) increased hippocampal serotonin levels fourfold without changing dopamine or noradrenaline. Atomoxetine, at dose levels that blocked the effects of escitalopram on contextual fear conditioning, increased the extracellular levels of noradrenaline eightfold but did not change dopamine or serotonin. A combined treatment of escitalopram and atomoxetine caused a significant attenuation of escitalopram-induced increase in serotonin levels, while noradrenaline levels were not affected. CONCLUSIONS These findings indicate that escitalopram affects fear memory in rats, likely modulated by increases in serotonin levels in the brain. This effect is impaired by atomoxetine, probably due to a noradrenaline-mediated decrease in serotonin levels. Further studies are warranted to study the effects of potential differences among antidepressant therapies on long-term cognitive outcomes.
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Cheke LG, Clayton NS. Mental time travel in animals. WILEY INTERDISCIPLINARY REVIEWS. COGNITIVE SCIENCE 2010; 1:915-930. [PMID: 26271786 DOI: 10.1002/wcs.59] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Lucy G Cheke
- Department of Experimental Psychology, University of Cambridge, Cambridge CB2 1TN, UK
| | - Nicola S Clayton
- Department of Experimental Psychology, University of Cambridge, Cambridge CB2 1TN, UK
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