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Contingency awareness, aging, and the parietal lobe. Neurobiol Aging 2020; 91:125-135. [PMID: 32241582 DOI: 10.1016/j.neurobiolaging.2020.02.024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 02/21/2020] [Accepted: 02/22/2020] [Indexed: 11/20/2022]
Abstract
Contingency awareness is thought to rely on an intact medial temporal lobe and also appears to be a function of age, as older subjects tend to be less aware. The current investigation used functional magnetic resonance imaging, transcranial direct current stimulation, and eyeblink classical conditioning to study brain processes related to contingency awareness as a function of age. Older adults were significantly less aware of the relationship between the tone-airpuff pairings than younger adults. Greater right parietal functional magnetic resonance imaging activation was associated with higher levels of contingency awareness for younger and older subjects. Cathodal transcranial direct current stimulation over the right parietal lobe led to lower levels of awareness in younger subjects without disrupting conditioned responses. Older adults exhibited hyperactivations in the parietal and medial temporal lobes, despite showing no conditioning deficits. These findings strongly support the idea that the parietal cortex serves as a substrate for contingency awareness and that age-related disruption of this region is sufficient to impair awareness, which may be a manifestation of some form of naturally occurring age-related neglect.
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Bolaram A, Coe TE, Power JM, Cheng DT. Awareness and differential eyeblink conditioning: effects of manipulating auditory CS frequencies. ACTA ACUST UNITED AC 2020; 27:78-82. [PMID: 31949039 PMCID: PMC6970424 DOI: 10.1101/lm.050146.119] [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: 06/13/2019] [Accepted: 11/22/2019] [Indexed: 11/24/2022]
Abstract
The role of awareness in differential delay eyeblink conditioning (EBC) has been a topic of much debate. We tested the idea that awareness is required for differential delay EBC when two cues are perceptually similar. The present study manipulated frequencies of auditory conditioned stimuli (CS) to vary CS similarity in three groups of participants. Our findings indicate that awareness was not necessary for differential delay EBC when two tones are easily discriminable, awareness was also not needed for relatively similar tones but may facilitate earlier conditioning, and awareness alone was not sufficient for differential delay EBC.
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Affiliation(s)
- Anudeep Bolaram
- Department of Psychology, Auburn University, Auburn, Alabama 36849, USA
| | - Taylor E Coe
- Department of Psychology, Auburn University, Auburn, Alabama 36849, USA
| | - John M Power
- Department of Physiology, University of New South Wales, Sydney 2052, Australia
| | - Dominic T Cheng
- Department of Psychology, Auburn University, Auburn, Alabama 36849, USA
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3
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Marshall HJ, Pezze MA, Fone KCF, Cassaday HJ. Age-related differences in appetitive trace conditioning and novel object recognition procedures. Neurobiol Learn Mem 2019; 164:107041. [PMID: 31351120 PMCID: PMC6857625 DOI: 10.1016/j.nlm.2019.107041] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Revised: 05/31/2019] [Accepted: 07/10/2019] [Indexed: 11/25/2022]
Abstract
Longitudinal study of middle age in the rat with matched younger control cohort. Appetitive trace conditioning and novel object recognition tests of working memory. Transient between-groups working memory impairments aged 12 compared with 2 months. Object exploration reduced with age but working memory recovered. Object exploration and ITI nosepoking showed some correlation with 5-HIAA/5-HT.
Appetitive trace conditioning (TC) was examined over 6 months in younger-adult (2–8 months) and middle-aged (12–18 months) male Wistar RccHan rats, to test for early age-related impairment in working memory. Novel object recognition (NOR) was included as a comparison task, to provide a positive control in the event that the expected impairment in TC was not demonstrated. The results showed that TC improved at both ages at the 2 s but not at the 10 s trace interval. There was, however, evidence for reduced improvement from one day to the next in the middle-aged cohort tested with the 2 s trace conditioned stimulus. Moreover, within the 10 s trace, responding progressively distributed later in the trace interval, in the younger-adult but not the middle-aged cohort. Middle-aged rats showed NOR discriminative impairment at a 24 h but not at a 10 min retention interval. Object exploration was overall reduced in middle-aged rats and further reduced longitudinally. At the end of the study, assessing neurochemistry by HPLC-ED showed reduced 5-HIAA/5-HT in the dorsal striatum of the middle-aged rats and some correlations between striatal 5-HIAA/5-HT and activity parameters. Overall the results suggest that, taken in isolation, age-related impairments may be overcome by experience. This recovery in performance was seen despite the drop in activity levels in older animals, which might be expected to contribute to cognitive decline.
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Affiliation(s)
- Hayley J Marshall
- University of Nottingham, Psychology, University Park, Nottingham NG72RD, United Kingdom
| | - Marie A Pezze
- University of Nottingham, Psychology, University Park, Nottingham NG72RD, United Kingdom
| | - Kevin C F Fone
- University of Nottingham, Psychology, University Park, Nottingham NG72RD, United Kingdom
| | - Helen J Cassaday
- University of Nottingham, Psychology, University Park, Nottingham NG72RD, United Kingdom.
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4
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Suter EE, Weiss C, Disterhoft JF. Differential responsivity of neurons in perirhinal cortex, lateral entorhinal cortex, and dentate gyrus during time-bridging learning. Hippocampus 2018; 29:511-526. [PMID: 30311282 DOI: 10.1002/hipo.23041] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 08/29/2018] [Accepted: 09/24/2018] [Indexed: 12/30/2022]
Abstract
Many studies have focused on the function of hippocampal region CA1 as a critical site for associative memory, but much less is known about changes in the afferents to CA1. Here we report the activity of multiple single neurons from perirhinal and entorhinal cortex and from dentate gyrus during trace eyeblink conditioning as well as consolidated recall, and in pseudo-conditioned control rabbits. We also report an analysis of theta activity filtered from the local field potential (LFP). Our results show early associative changes in single-neuron firing rate as well as theta oscillations in lateral entorhinal cortex (EC) and dentate gyrus (DG), and increases in the number of responsive neurons in perirhinal cortex. In both EC and DG, a subset of neurons from conditioned animals exhibited an elevated baseline firing rate and large responses to the conditioned stimulus and trace period. A similar population of cells has been seen in DG and in medial, but not lateral, EC during spatial tasks, suggesting that lateral EC contains cells responsive to a temporal associative task. In contrast to recent studies in our laboratory that found significant CA1 contributions to long-term memory, the activity profiles of neurons within EC and DG were similar for conditioned and pseudoconditioned rabbits during post-consolidation sessions. Collectively these results demonstrate that individual subregions of medial temporal lobe differentially support new and remotely acquired memories. Neuron firing profiles were similar on training trials when conditioned responses were and were not exhibited, demonstrating that these temporal lobe regions represent the CS-US association and do not control the behavioral response. The analysis of theta activity revealed that theta power was modulated by the conditioning stimuli in both the conditioned and pseudoconditioned groups and that although both groups exhibited a resetting of phase to the corneal airpuff, only the conditioned group exhibited a resetting of phase to the whisker conditioned stimulus.
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Affiliation(s)
- Eugénie E Suter
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Craig Weiss
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - John F Disterhoft
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
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Connor DA, Gould TJ. The role of working memory and declarative memory in trace conditioning. Neurobiol Learn Mem 2016; 134 Pt B:193-209. [PMID: 27422017 PMCID: PMC5755400 DOI: 10.1016/j.nlm.2016.07.009] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 07/07/2016] [Accepted: 07/11/2016] [Indexed: 01/18/2023]
Abstract
Translational assays of cognition that are similarly implemented in both lower and higher-order species, such as rodents and primates, provide a means to reconcile preclinical modeling of psychiatric neuropathology and clinical research. To this end, Pavlovian conditioning has provided a useful tool for investigating cognitive processes in both lab animal models and humans. This review focuses on trace conditioning, a form of Pavlovian conditioning typified by the insertion of a temporal gap (i.e., trace interval) between presentations of a conditioned stimulus (CS) and an unconditioned stimulus (US). This review aims to discuss pre-clinical and clinical work investigating the mnemonic processes recruited for trace conditioning. Much work suggests that trace conditioning involves unique neurocognitive mechanisms to facilitate formation of trace memories in contrast to standard Pavlovian conditioning. For example, the hippocampus and prefrontal cortex (PFC) appear to play critical roles in trace conditioning. Moreover, cognitive mechanistic accounts in human studies suggest that working memory and declarative memory processes are engaged to facilitate formation of trace memories. The aim of this review is to integrate cognitive and neurobiological accounts of trace conditioning from preclinical and clinical studies to examine involvement of working and declarative memory.
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Affiliation(s)
- David A Connor
- Department of Psychology, Neuroscience Program, Temple University, Philadelphia, PA 19122, United States
| | - Thomas J Gould
- Department of Psychology, Neuroscience Program, Temple University, Philadelphia, PA 19122, United States.
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Wang K, Mateos-Aparicio P, Hönigsperger C, Raghuram V, Wu WW, Ridder MC, Sah P, Maylie J, Storm JF, Adelman JP. IK1 channels do not contribute to the slow afterhyperpolarization in pyramidal neurons. eLife 2016; 5:e11206. [PMID: 26765773 PMCID: PMC4733036 DOI: 10.7554/elife.11206] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 12/01/2015] [Indexed: 11/16/2022] Open
Abstract
In pyramidal neurons such as hippocampal area CA1 and basolateral amygdala, a slow afterhyperpolarization (sAHP) follows a burst of action potentials, which is a powerful regulator of neuronal excitability. The sAHP amplitude increases with aging and may underlie age related memory decline. The sAHP is due to a Ca2+-dependent, voltage-independent K+ conductance, the molecular identity of which has remained elusive until a recent report suggested the Ca2+-activated K+ channel, IK1 (KCNN4) as the sAHP channel in CA1 pyramidal neurons. The signature pharmacology of IK1, blockade by TRAM-34, was reported for the sAHP and underlying current. We have examined the sAHP and find no evidence that TRAM-34 affects either the current underling the sAHP or excitability of CA1 or basolateral amygdala pyramidal neurons. In addition, CA1 pyramidal neurons from IK1 null mice exhibit a characteristic sAHP current. Our results indicate that IK1 channels do not mediate the sAHP in pyramidal neurons. DOI:http://dx.doi.org/10.7554/eLife.11206.001 Neurons carry signals in the form of electrical impulses called action potentials. These nerve impulses result from ions flowing through proteins called ion channels in the neuron’s membrane, and they determine how the neuron communicates with neighboring neurons. The number of action potentials a neuron can produce can vary over a wide range. In the brain, a particular kind of ion channel limits the number of action potentials that many neurons produce via a negative feedback mechanism. That is to say, nerve impulses activate this ion channel and the activated channel then makes the neuron less able to send further nerve impulses for a while.The activity of this ion channel increases with age and it may be responsible for some forms of age-related decline in cognitive abilities. However, the exact identity of the ion channel responsible was unclear. Recent research has suggested the ion channel in question was a protein called IK1. This conclusion was largely based on how this ion channel responded to drugs in the laboratory. Wang, Materos-Aparico et al. sought to verify this conclusion and, in contrast with the previous reports, found that the IK1 ion channel did not respond to these drugs in the same way when it was in neurons in the brains of mice. In further experiments, mice that had been engineered to lack the IK1 ion channel still showed the characteristic negative feedback that regulates the firing of action potentials. Thus, Wang, Materos-Aparico et al. found no evidence to support the previous conclusion, and instead conclude that the exact identity of this important ion channel in the brain has yet to be defined. DOI:http://dx.doi.org/10.7554/eLife.11206.002
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Affiliation(s)
- Kang Wang
- Vollum Institute, Oregon Health and Science University, Portland, United States
| | - Pedro Mateos-Aparicio
- Department of Physiology, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Christoph Hönigsperger
- Department of Physiology, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Vijeta Raghuram
- Vollum Institute, Oregon Health and Science University, Portland, United States
| | - Wendy W Wu
- Department of Obstetrics and Gynecology, Oregon Health and Science University, Portland, United States
| | - Margreet C Ridder
- Queensland Brain Institute, The University of Queensland, Brisbane, Australia
| | - Pankaj Sah
- Queensland Brain Institute, The University of Queensland, Brisbane, Australia
| | - Jim Maylie
- Department of Obstetrics and Gynecology, Oregon Health and Science University, Portland, United States
| | - Johan F Storm
- Department of Physiology, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - John P Adelman
- Vollum Institute, Oregon Health and Science University, Portland, United States
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Weiss C, Disterhoft JF. Eyeblink Conditioning and Novel Object Recognition in the Rabbit: Behavioral Paradigms for Assaying Psychiatric Diseases. Front Psychiatry 2015; 6:142. [PMID: 26500564 PMCID: PMC4595794 DOI: 10.3389/fpsyt.2015.00142] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 09/22/2015] [Indexed: 11/13/2022] Open
Abstract
Analysis of data collected from behavioral paradigms has provided important information for understanding the etiology and progression of diseases that involve neural regions mediating abnormal behavior. The trace eyeblink conditioning (EBC) paradigm is particularly suited to examine cerebro-cerebellar interactions since the paradigm requires the cerebellum, forebrain, and awareness of the stimulus contingencies. Impairments in acquiring EBC have been noted in several neuropsychiatric conditions, including schizophrenia, Alzheimer's disease (AD), progressive supranuclear palsy, and post-traumatic stress disorder. Although several species have been used to examine EBC, the rabbit is unique in its tolerance for restraint, which facilitates imaging, its relatively large skull that facilitates chronic neuronal recordings, a genetic sequence for amyloid that is identical to humans which makes it a valuable model to study AD, and in contrast to rodents, it has a striatum that is differentiated into a caudate and a putamen that facilitates analysis of diseases involving the striatum. This review focuses on EBC during schizophrenia and AD since impairments in cerebro-cerebellar connections have been hypothesized to lead to a cognitive dysmetria. We also relate EBC to conditioned avoidance responses that are more often examined for effects of antipsychotic medications, and we propose that an analysis of novel object recognition (NOR) may add to our understanding of how the underlying neural circuitry has changed during disease states. We propose that the EBC and NOR paradigms will help to determine which therapeutics are effective for treating the cognitive aspects of schizophrenia and AD, and that neuroimaging may reveal biomarkers of the diseases and help to evaluate potential therapeutics. The rabbit, thus, provides an important translational system for studying neural mechanisms mediating maladaptive behaviors that underlie some psychiatric diseases, especially cognitive impairments associated with schizophrenia and AD, and object recognition provides a simple test of memory that can corroborate the results of EBC.
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Affiliation(s)
- Craig Weiss
- Department of Physiology, Northwestern University Feinberg School of Medicine , Chicago, IL , USA
| | - John F Disterhoft
- Department of Physiology, Northwestern University Feinberg School of Medicine , Chicago, IL , USA
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Huang H, Wu B, Li Q, Yao J, Li X, Yang Y, Wu GY, Sui JF. Awareness is essential for differential delay eyeblink conditioning with soft-tone but not loud-tone conditioned stimuli. Neurosci Bull 2014; 30:433-40. [PMID: 24477990 PMCID: PMC5562602 DOI: 10.1007/s12264-013-1400-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Accepted: 09/03/2013] [Indexed: 12/22/2022] Open
Abstract
The role of awareness in differential delay eyeblink conditioning (DEC) remains controversial. Here, we investigated the involvement of awareness in differential DEC with a soft or a loud tone as the conditioned stimulus (CS). In the experiment, 36 participants were trained in differential DEC with a soft tone (60 dB) or a loud tone (85 dB) as the CS, paired with a corneal air-puff as the unconditioned stimulus (US). After conditioning, awareness of the relationship between the CS and the US was assessed with a 17-item true/false questionnaire. Interestingly, during differential DEC with a soft-tone CS, a higher proportion of differential conditioned responses (CRs) was evident in participants who were aware than those who were unaware. In contrast, when a loud tone was used as the CS, the proportion of differential CRs of the aware participants did not differ significantly from those who were unaware over any of the blocks of 20 trials. In unaware participants, the percentage of differential CRs with a loud-tone CS was significantly higher than that with a soft-tone CS; however in participants classified as aware, the percentage of differential CRs with a loud-tone CS did not differ significantly from that with a soft-tone CS. The present findings suggest that awareness is critical for differential DEC when the delay task is rendered more difficult.
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Affiliation(s)
- He Huang
- Department of Physiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing, 400038 China
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Third Military Medical University, Chongqing, 400038 China
| | - Bing Wu
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Third Military Medical University, Chongqing, 400038 China
| | - Qiong Li
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Third Military Medical University, Chongqing, 400038 China
| | - Juan Yao
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Third Military Medical University, Chongqing, 400038 China
| | - Xuan Li
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Third Military Medical University, Chongqing, 400038 China
| | - Yi Yang
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Third Military Medical University, Chongqing, 400038 China
| | - Guang-Yan Wu
- Department of Physiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing, 400038 China
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Third Military Medical University, Chongqing, 400038 China
| | - Jian-Feng Sui
- Department of Physiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing, 400038 China
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Third Military Medical University, Chongqing, 400038 China
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Effects of OEF/OIF-related physical and emotional co-morbidities on associative learning: concurrent delay and trace eyeblink classical conditioning. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2014; 11:3046-73. [PMID: 24625622 PMCID: PMC3987020 DOI: 10.3390/ijerph110303046] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Revised: 02/19/2014] [Accepted: 02/20/2014] [Indexed: 12/22/2022]
Abstract
This study examined the performance of veterans and active duty personnel who served in Operation Enduring Freedom and/or Operation Iraqi Freedom (OEF/OIF) on a basic associative learning task. Eighty-eight individuals participated in this study. All received a comprehensive clinical evaluation to determine the presence and severity of posttraumatic stress disorder (PTSD) and traumatic brain injury (TBI). The eyeblink conditioning task was composed of randomly intermixed delay and trace conditioned stimulus (CS) and unconditioned stimulus (US) pairs (acquisition) followed by a series of CS only trials (extinction). Results revealed that those with a clinical diagnosis of PTSD or a diagnosis of PTSD with comorbid mTBI acquired delay and trace conditioned responses (CRs) to levels and at rates similar to a deployed control group, thus suggesting intact basic associative learning. Differential extinction impairment was observed in the two clinical groups. Acquisition of CRs for both delay and trace conditioning, as well as extinction of trace CRs, was associated with alcoholic behavior across all participants. These findings help characterize the learning and memory function of individuals with PTSD and mTBI from OEF/OIF and raise the alarming possibility that the use of alcohol in this group may lead to more significant cognitive dysfunction.
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Schreurs BG, Smith-Bell CA, Wang D, Burhans LB. Dietary cholesterol degrades rabbit long term memory for discrimination learning but facilitates acquisition of discrimination reversal. Neurobiol Learn Mem 2013; 106:238-45. [PMID: 24076265 DOI: 10.1016/j.nlm.2013.09.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Revised: 09/11/2013] [Accepted: 09/16/2013] [Indexed: 01/01/2023]
Abstract
We have shown previously that feeding dietary cholesterol before learning can improve acquisition whereas feeding cholesterol after learning can degrade long term memory. To examine these different findings within a single paradigm, we fed groups of rabbits 2% cholesterol or normal chow with or without 0.12 ppm copper added to the drinking water following two-tone discrimination learning of the nictitating membrane response in which a 8-kHz tone (conditioned stimulus, CS+) was followed by air puff and a 1-kHz tone (CS-) was not. After eight weeks on the diet, we assessed the rabbits' conditioned responding during testing and retraining. We then reversed the two-tone discrimination and assessed responding to the 1-kHz tone CS+ and the 8-kHz CS-. During testing, rabbits given cholesterol without copper had lower levels of responding to CS+ than rabbits in the other groups suggesting they did not retain the discrimination as well. However, during a brief discrimination retraining session, their response levels to the CS+ returned to the level of the other groups, demonstrating a return of the memory of the original discrimination. At the end of discrimination reversal, these same rabbits exhibited superior discrimination indexed by lower response levels to CS- but similar levels to CS+, suggesting they were better able to acquire the new relationship between the two tones by inhibiting CS- responses. These results add to our previous data by showing cholesterol diet-induced degradation of an old memory and facilitation of a new memory can both be demonstrated within a discrimination reversal paradigm. Given discrimination reversal is a hippocampally-dependent form of learning, the data support the role of cholesterol in modifying hippocampal function as we have shown previously with in vitro brain slice recordings.
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Affiliation(s)
- Bernard G Schreurs
- Blanchette Rockefeller Neurosciences Institute, West Virginia University, Morgantown, WV, United States; Department of Physiology and Pharmacology, West Virginia University, Morgantown, WV, United States.
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Suter EE, Weiss C, Disterhoft JF. Perirhinal and postrhinal, but not lateral entorhinal, cortices are essential for acquisition of trace eyeblink conditioning. Learn Mem 2013; 20:80-4. [PMID: 23322556 DOI: 10.1101/lm.028894.112] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The acquisition of temporal associative tasks such as trace eyeblink conditioning is hippocampus-dependent, while consolidated performance is not. The parahippocampal region mediates much of the input and output of the hippocampus, and perirhinal (PER) and entorhinal (EC) cortices support persistent spiking, a possible mediator of temporal bridging between stimuli. Here we show that lesions of the perirhinal or postrhinal cortex severely impair the acquisition of trace eyeblink conditioning, while lateral EC lesions do not. Our findings suggest that direct projections from the PER to the hippocampus are functionally important in trace acquisition, and support a role for PER persistent spiking in time-bridging associations.
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Affiliation(s)
- Eugénie E Suter
- Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, USA.
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12
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Weiss C, Disterhoft JF. Exploring prefrontal cortical memory mechanisms with eyeblink conditioning. Behav Neurosci 2011; 125:318-26. [PMID: 21517143 DOI: 10.1037/a0023520] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Several studies in nonhuman primates have shown that neurons in the dorsolateral prefrontal cortex have activity that persists throughout the delay period in delayed matching to sample tasks, and age-related changes in the microcolumnar organization of the prefrontal cortex are significantly correlated with age-related declines in cognition. Activity that persists beyond the presentation of a stimulus could mediate working memory processes, and disruption of those processes could account for memory deficits that often accompany the aging process. These potential memory and aging mechanisms are being systematically examined with eyeblink conditioning paradigms in nonprimate mammalian animal models including the rabbit. The trace version of the conditioning paradigm is a particularly good system to explore declarative memory since humans do not acquire trace conditioning if they are unable to become cognitively aware of the association between a conditioning tone and an airpuff to the eye. This conditioning paradigm has been used to show that the hippocampus and cerebellum interact functionally since both conditioned responses and conditioned hippocampal pyramidal neuron activity are abolished following lesions of the cerebellar nuclei and since hippocampal lesions prevent or abolish trace conditioned blinks. However, because there are no direct connections between the hippocampal formation and the cerebellum, and because the hippocampus is not necessary for trace conditioning after a period of consolidation has elapsed, we and others have been examining the prefrontal cortex for its role in forebrain-dependent trace eyeblink conditioning. This review examines some of the literature which suggests that the prefrontal cortex serves to orchestrate a neuronal network that interacts with the cerebellum to mediate adaptively timed conditioned responses.
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Affiliation(s)
- Craig Weiss
- Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611-3008, USA.
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13
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Mutter SA, Atchley AR, Plumlee LM. Aging and retrospective revaluation of causal learning. J Exp Psychol Learn Mem Cogn 2011; 38:102-17. [PMID: 21843025 DOI: 10.1037/a0024851] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In a 2-stage causal learning task, young and older participants first learned which foods presented in compound were followed by an allergic reaction (e.g., STEAK-BEANS→ REACTION) and then the causal efficacy of 1 food from these compounds was revalued (e.g., BEANS→ NO REACTION). In Experiment 1, unrelated food pairs were used, and although there were no age differences in compound- or single-cue-outcome learning, older adults did not retrospectively revalue the causal efficacy of the absent target cues (e.g., STEAK). However, they had weaker within-compound associations for the unrelated foods, and this may have prevented them from retrieving the representations of these cues. In Experiment 2, older adults still showed no retrospective revaluation of absent cues even though compound food cues with pre-existing associations were used (e.g., STEAK-POTATO), and they received additional learning trials. Finally, in Experiment 3, older adults revalued the causal efficacy of the target cues when small, unobtrusive icons of these cues were present during single-cue revaluation. These findings suggest that age-related deficits in causal learning for absent cues are due to ineffective associative binding and reactivation processes.
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Affiliation(s)
- Sharon A Mutter
- Department of Psychology, Western Kentucky University, Bowling Green, KY 42101, USA.
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14
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Galvez R, Nicholson DA, Disterhoft JF. Physiological and anatomical studies of associative learning: Convergence with learning studies of W.T. Greenough. Dev Psychobiol 2011; 53:489-504. [PMID: 21678397 PMCID: PMC3632307 DOI: 10.1002/dev.20554] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The quest to understand how the brain is able to store information for later retrieval has been pursued by many scientists through the years. Although many have made very significant contributions to the field and our current understanding of the process, few have played as pivotal a role in advancing our understanding as William T. Greenough. The current report will utilize associative learning, a training paradigm that has greatly assisted in our understanding of memory consolidation, to demonstrate how findings emerging from the Greenough laboratory helped to not only shape our current understanding of learning induced anatomical plasticity, but to also launch future analyses into the molecular players involved in this process, especially the Fragile X Mental Retardation Protein.
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Affiliation(s)
- Roberto Galvez
- Department of Psychology, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, USA
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15
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Cheng DT, Faulkner ML, Disterhoft JF, Desmond JE. The effects of aging in delay and trace human eyeblink conditioning. Psychol Aging 2011; 25:684-90. [PMID: 20677885 DOI: 10.1037/a0017978] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Normal aging has been shown to impact performance during human eyeblink classical conditioning, with older adults showing lower conditioning levels than younger adults. Previous findings showed younger adults can acquire both delay and trace conditioning concurrently, but it is not known whether older adults can learn under the same conditions. Present results indicated older adults did not produce a significantly greater number of conditioned responses during acquisition, but their ability to time eyeblink responses prior to the unconditioned stimulus was preserved. The decline in eyeblink conditioning that typically accompanies aging has been extended to concurrent presentations of delay and trace conditioning trials.
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Affiliation(s)
- Dominic T Cheng
- Johns Hopkins University School of Medicine, Department of Neurology, Division of Cognitive Neuroscience, Baltimore, MD 21205, USA.
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16
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Abstract
Getting gray hair is part of the natural progression of aging. People expect it and they can change their hair color, if they choose. People also expect increases in memory lapses and learning difficulties as they get older. However, unlike hair color, there is no magic cure or option to fix learning and memory difficulties, because the cellular mechanisms of learning and aging in all the different types of neurons throughout the brain have yet to be discovered. This review describes our efforts to identify a cellular biomarker in hippocampal pyramidal neurons that has been demonstrated to reliably change with learning and with aging - the postburst afterhyperpolarization. We propose that this biomarker, which plays a critical role in regulating neuronal excitability, can be used as a benchmark for future studies in order to understand and identify the cellular mechanisms of learning and aging in the hippocampus, as well as in other cortical regions.
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Affiliation(s)
- M Matthew Oh
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611-3008, USA, Tel.: +1 312 503 5123, ,
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17
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Galvez R, Cua S, Disterhoft JF. Age-related deficits in a forebrain-dependent task, trace-eyeblink conditioning. Neurobiol Aging 2009; 32:1915-22. [PMID: 20018411 DOI: 10.1016/j.neurobiolaging.2009.11.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2009] [Revised: 11/10/2009] [Accepted: 11/20/2009] [Indexed: 10/20/2022]
Abstract
Trace-eyeblink conditioning is a forebrain-dependent learning paradigm that has assisted in our understanding of age-related hippocampal neuronal plasticity; however, the hippocampus is not believed to be the permanent site for most long-term-memory storage. Studies in adult subjects have suggested the neocortex as one such site. Whisker plucking studies have further suggested that the ability for plasticity in the neocortex declines with age. Mice were trained in trace- and delay-eyeblink conditioning with whisker or auditory stimulation as the conditioned stimulus to examine possible age-related behavioral and neocortical abnormalities. Whisker stimulation was determined to be a more effective stimulus for examining age-related behavioral abnormalities in C57 mice. Additionally, neocortical barrel expansion, observed in trace conditioned adult mice and rabbits, does not occur in mice conditioned on a delay paradigm or in old mice unable to learn the whisker trace association. Abnormalities in neocortical memory storage in the elderly could contribute to normal age-dependent declines in associative learning abilities.
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Affiliation(s)
- Roberto Galvez
- Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA.
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18
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Fortier CB, Maksimovskiy AL, Venne JR, LaFleche G, McGlinchey RE. Silent trace eliminates differential eyeblink learning in abstinent alcoholics. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2009; 6:2007-27. [PMID: 19742168 PMCID: PMC2738895 DOI: 10.3390/ijerph6072007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/19/2009] [Accepted: 07/10/2009] [Indexed: 11/16/2022]
Abstract
Chronic alcoholism has profound effects on the brain, including volume reductions in regions critical for eyeblink classical conditioning (EBCC). The current study challenged abstinent alcoholics using delay (n = 20) and trace (n = 17) discrimination/reversal EBCC. Comparisons revealed a significant difference between delay and trace conditioning performance during reversal (t (35) = 2.08, p < 0.05). The difference between the two tasks for discrimination was not significant (p = 0.44). These data support the notion that alcoholics are increasingly impaired in the complex task of reversing a previously learned discrimination when a silent trace interval is introduced. Alcoholics' impairment in flexibly altering learned associations may be central to their continued addiction.
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Affiliation(s)
- Catherine Brawn Fortier
- Geriatric Research Education and Clinical Center (GRECC), VA Boston Healthcare System; Boston, MA, USA; E-Mails:
(A.L.M.);
(J.R.V.)
- Department of Psychiatry, Harvard Medical School; Boston, MA, USA; E-Mail:
- Author to whom correspondence should be addressed; E-Mail:
; Tel.: +1-857-364-4361
| | - Arkadiy L. Maksimovskiy
- Geriatric Research Education and Clinical Center (GRECC), VA Boston Healthcare System; Boston, MA, USA; E-Mails:
(A.L.M.);
(J.R.V.)
| | - Jonathan R. Venne
- Geriatric Research Education and Clinical Center (GRECC), VA Boston Healthcare System; Boston, MA, USA; E-Mails:
(A.L.M.);
(J.R.V.)
| | - Ginette LaFleche
- Memory Disorders Research Center (MDRC), Boston University School of Medicine & VA Boston Healthcare System; Boston, MA, USA; E-Mail:
| | - Regina E. McGlinchey
- Geriatric Research Education and Clinical Center (GRECC), VA Boston Healthcare System; Boston, MA, USA; E-Mails:
(A.L.M.);
(J.R.V.)
- Department of Psychiatry, Harvard Medical School; Boston, MA, USA; E-Mail:
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Fortier CB, Steffen EM, LaFleche G, Venne JR, Disterhoft JF, McGlinchey RE. Delay discrimination and reversal eyeblink classical conditioning in abstinent chronic alcoholics. Neuropsychology 2008; 22:196-208. [PMID: 18331162 DOI: 10.1037/0894-4105.22.2.196] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Evidence has shown that alcoholism leads to volume reductions in brain regions critical for associative learning using the eyeblink classical conditioning paradigm (EBCC). Evidence indicates that cerebellar shrinkage causes impairment in simple forms of EBCC, whereas changes in forebrain structures result in impairment in more complex tasks. In this study, the ability of abstinent alcoholics and matched control participants to acquire learned responses during delay discrimination and discrimination reversal was examined and related to severity of drinking history and neuropsychological performance. During discrimination learning, one tone (CS+) predicted the occurrence of an airpuff (unconditioned stimulus), and another tone (CS-) served as a neutral stimulus; then the significance of the tones was reversed. Alcoholics who learned the initial discrimination were impaired in acquiring the new CS+ after the tones reversed; this is a function that has previously been linked to forebrain structures. It is suggested that a factor important to alcoholic addiction may be the presence of alcoholic-related associative responses that interfere with the ability to learn new more adaptive associations.
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Affiliation(s)
- Catherine Brawn Fortier
- Geriatric Research Education and Clinical Center (GRECC), Veterans Affairs Boston Healthcare System
| | - Elizabeth M Steffen
- Geriatric Research Education and Clinical Center (GRECC), Veterans Affairs Boston Healthcare System
| | - Ginette LaFleche
- Memory Disorders Research Center (MDRC), Boston University School of Medicin
| | - Jonathan R Venne
- Geriatric Research Education and Clinical Center (GRECC), Veterans Affairs Boston Healthcare System
| | - John F Disterhoft
- Department of Physiology, Northwestern University, Feinberg School of Medicine
| | - Regina E McGlinchey
- Geriatric Research Education and Clinical Center (GRECC), Veterans Affairs Boston Healthcare System
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Smith CN, Hopkins RO, Squire LR. Experience-dependent eye movements, awareness, and hippocampus-dependent memory. J Neurosci 2006; 26:11304-12. [PMID: 17079658 PMCID: PMC2424210 DOI: 10.1523/jneurosci.3071-06.2006] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
We asked what kind of memory is operating when eye movements change as the result of experience. Participants viewed scenes that were either novel, repeated, or manipulated (i.e., a change was introduced in one region of the scene). Eye movements differed depending on the past viewing history of each scene. Participants made fewer fixations and sampled fewer regions when scenes were repeated than when scenes were novel. When scenes were altered, participants made more fixations in the altered region, spent more time looking at the altered region, and made more transitions into and out of the altered region than in unchanged (matched) regions in the repeated scenes. Importantly, these effects occurred only when individuals were aware that a change had occurred. Participants who were unaware that the scene had been altered looked at the changed scenes in the same way that they looked at repeated scenes. Thus, there was no indication that eye movements could reveal an unaware (unconscious) form of memory. Instead, eye movements reflected conscious memory of whether the scene was repeated or manipulated. The findings were the same when awareness was assessed after viewing all the scenes (experiment 1) and when awareness was assessed after each scene was presented (experiment 2). In experiment 3, memory-impaired patients with damage limited to the hippocampus were impaired at deciding whether scenes were novel, repeated, or manipulated. Thus, the ability to consciously recollect recent encounters with scenes reflects a form of hippocampus-dependent memory. The findings show that experience-dependent eye movements in response to altered scenes reflect conscious, declarative memory, and they support the link between aware memory, declarative memory, and hippocampus-dependent memory.
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Affiliation(s)
| | - Ramona O. Hopkins
- Psychology Department and Neuroscience Center, Brigham Young University, Provo, Utah 84602
- Department of Medicine, Pulmonary, and Critical Care Division, LDS Hospital, Salt Lake City, Utah 84143, and
| | - Larry R. Squire
- Departments of Psychiatry
- Psychology, and
- Neuroscience, University of California, San Diego, La Jolla, California 92093
- Veterans Affairs Medical Center 116A, San Diego, California 92161
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Smith CN, Clark RE, Manns JR, Squire LR. Acquisition of differential delay eyeblink classical conditioning is independent of awareness. Behav Neurosci 2005; 119:78-86. [PMID: 15727514 PMCID: PMC2773180 DOI: 10.1037/0735-7044.119.1.78] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
There has been debate about whether differential delay eyeblink conditioning can be acquired without awareness of the stimulus contingencies. In 4 experiments, the authors reexamined this question. Older participants were tested with a tone and white noise (Experiment 1) or with 2 tones (Experiment 2). In addition, younger participants were tested with 2 tones (Experiment 3) or with 2 tones plus the parameters from an earlier study that had reported a relationship between conditioning and awareness (Experiment 4). Participants who were designated aware of the stimulus contingencies and participants who were designated unaware exhibited equivalent levels of differential eyeblink conditioning. Awareness of stimulus contingencies is not required for differential delay eyeblink conditioning when simple conditioned stimuli are used.
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Affiliation(s)
- Christine N Smith
- Institute for Neural Computation, University of California, San Diego, CA, USA
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22
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Abstract
To associate events that are disparate in time, the brain must record, retain and perhaps even reflect on the individual events themselves. Aspects of such learning can be probed with trace conditioning, during which an animal learns to associate events that are temporally distant from one another. For decades, we have known that the formation of so-called trace memories (in which one stimulus is associated with a second stimulus that is discontinuous and later in time) depends on the hippocampal formation. Recent findings indicate that the hippocampus is crucial for the initial acquisition of trace memories but not for their expression or long-term storage. More recent findings implicate neurogenesis, synaptogenesis and awareness in the formation of trace memories.
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Affiliation(s)
- Tracey J Shors
- Department of Psychology, Center for Collaborative Neuroscience, Rutgers University, 152 Frelinghuysen Road, Piscataway, NJ 08854, USA.
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Fortier CB, Disterhoft JF, Capozzi S, Kilduff P, Cronin-Golomb A, McGlinchey RE. Conditional discrimination learning in patients with bilateral medial temporal lobe amnesia. Behav Neurosci 2004; 117:1181-95. [PMID: 14674839 PMCID: PMC2430040 DOI: 10.1037/0735-7044.117.6.1181] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The ability of bilateral medial temporal lobe amnesic patients (MT; n=8) and normal participants (NC; n=8) to acquire a conditional discrimination in trace and delay eyeblink conditioning paradigms was investigated. Experiment 1 assessed trace conditional discrimination learning by using a light conditional stimulus (S+/S-) and tone conditioned stimulus (CS) separated by a 1-s trace. NCs responded differentially on S+ trials (mean percent conditioned responses=66) versus S- trials (30). Whereas MTs were impaired in their acquisition of the conditional discrimination (S+ =51, S- =43). In Experiment 2, the temporal separation was eliminated. NCs acquired the conditional discrimination (S+ =70, S- =29). MTs were unable to respond differentially (S+ =42, S- =37). The findings indicate that the hippocampal system is essential in acquiring a conditional discrimination, even in a delay paradigm.
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Weible AP, Oh MM, Lee G, Disterhoft JF. Galantamine facilitates acquisition of hippocampus-dependent trace eyeblink conditioning in aged rabbits. Learn Mem 2004; 11:108-15. [PMID: 14747524 PMCID: PMC321321 DOI: 10.1101/lm.69804] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2003] [Accepted: 10/14/2003] [Indexed: 11/25/2022]
Abstract
Cholinergic systems are critical to the neural mechanisms mediating learning. Reduced nicotinic cholinergic receptor (nAChR) binding is a hallmark of normal aging. These reductions are markedly more severe in some dementias, such as Alzheimer's disease. Pharmacological central nervous system therapies are a means to ameliorate the cognitive deficits associated with normal aging and aging-related dementias. Trace eyeblink conditioning (EBC), a hippocampus- and forebrain-dependent learning paradigm, is impaired in both aged rabbits and aged humans, attributable in part to cholinergic dysfunction. In the present study, we examined the effects of galantamine (3 mg/kg), a cholinesterase inhibitor and nAChR allosteric potentiating ligand, on the acquisition of trace EBC in aged (30-33 months) and young (2-3 months) female rabbits. Trace EBC involves the association of a conditioned stimulus (CS) with an unconditioned stimulus (US), separated by a stimulus-free trace interval. Repeated CS-US pairings results in the development of the conditioned eyeblink response (CR) prior to US onset. Aged rabbits receiving daily injections of galantamine (Aged/Gal) exhibited significant improvements compared with age-matched controls in trials to eight CRs in 10 trial block criterion (P = 0.0402) as well as performance across 20 d of training [F(1,21) = 5.114, P = 0.0345]. Mean onset and peak latency of CRs exhibited by Aged/Gal rabbits also differed significantly [F(1,21) = 6.120/6.582, P = 0.0220/0.0180, respectively] compared with age-matched controls, resembling more closely CR timing of young drug and control rabbits. Galantamine did not improve acquisition rates in young rabbits compared with age-matched controls. These data indicate that by enhancing nicotinic and muscarinic transmission, galantamine is effective in offsetting the learning deficits associated with decreased cholinergic transmission in the aging brain.
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Affiliation(s)
- Aldis P Weible
- Department of Physiology and Institute for Neuroscience, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, USA.
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