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Nitzan N, Buzsáki G. Physiological characteristics of neurons in the mammillary bodies align with topographical organization of subicular inputs. Cell Rep 2024; 43:114539. [PMID: 39052483 DOI: 10.1016/j.celrep.2024.114539] [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: 04/16/2024] [Revised: 05/20/2024] [Accepted: 07/09/2024] [Indexed: 07/27/2024] Open
Abstract
The mammillary bodies (MBOs), a group of hypothalamic nuclei, play a pivotal role in memory formation and spatial navigation. They receive extensive inputs from the hippocampus through the fornix, but the physiological significance of these connections remains poorly understood. Damage to the MBOs is associated with various forms of anterograde amnesia. However, information about the physiological characteristics of the MBO is limited, primarily due to the limited number of studies that have directly monitored MBO activity along with population patterns of its upstream partners. Employing large-scale silicon probe recording in mice, we characterize MBO activity and its interaction with the subiculum across various brain states. We find that MBO cells are highly diverse in their relationship to theta, ripple, and slow oscillations. Several of the physiological features are inherited by the topographically organized inputs to MBO cells. Our study provides insights into the functional organization of the MBOs.
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Affiliation(s)
- Noam Nitzan
- New York University Neuroscience Institute, New York University, New York, NY 10016, USA; Center for Neural Science, New York University, New York, NY 10016, USA
| | - György Buzsáki
- New York University Neuroscience Institute, New York University, New York, NY 10016, USA; Center for Neural Science, New York University, New York, NY 10016, USA.
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Akaishi T, Asari M, Sekiguchi S, Muroya T, Hasebe M. A Case With Bilateral Hippocampal Infarction Resembling Transient Global Amnesia. J Med Cases 2024; 15:159-166. [PMID: 39091574 PMCID: PMC11287902 DOI: 10.14740/jmc4240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2024] [Accepted: 06/11/2024] [Indexed: 08/04/2024] Open
Abstract
Transient global amnesia (TGA) is a benign and transient condition with a sudden short-term amnesia. One of the conditions resembling TGA is hippocampal infarction, which requires relapse prevention treatments. In this report, we present a case with bilateral hippocampal infarction in whom distinguishing these two conditions was difficult for up to 1 week from the onset. A 60-year-old female visited our hospital with sudden onset retrograde and anterograde amnesia. Thin-slice magnetic resonance imaging (MRI) with 2-mm thickness revealed hyperintense signals on diffusion-weighted imaging (DWI) with signal loss on apparent diffusion coefficient (ADC) on both sides of the hippocampus. MRI with 5-mm thickness on day 7 revealed persistent restricted diffusion on both sides, one of which was still with decreased ADC values. Based on this finding, the diagnosis of bilateral hippocampal infarction was reached, and the relapse-preventive antiplatelet was continued. This case implied the potential difficulty of distinguishing cases with TGA and those with hippocampal infarction based on MRI findings within the first several days after onset. Thin-slice brain MRI, careful search of potential cardiovascular risks, and follow-up MRI ≥ 7 days after onset will be helpful to reach a correct diagnosis in cases with sudden amnesia.
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Affiliation(s)
- Tetsuya Akaishi
- Department of Education and Support for Regional Medicine, Tohoku University, Sendai, Japan
| | - Mami Asari
- Department of Neurology, Izumi Hospital, Sendai, Japan
| | | | - Tomoko Muroya
- Department of Neurology, Izumi Hospital, Sendai, Japan
| | - Makoto Hasebe
- Department of Neurology, Izumi Hospital, Sendai, Japan
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3
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Pirazzini G, Ursino M. Modeling the contribution of theta-gamma coupling to sequential memory, imagination, and dreaming. Front Neural Circuits 2024; 18:1326609. [PMID: 38947492 PMCID: PMC11211613 DOI: 10.3389/fncir.2024.1326609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Accepted: 05/24/2024] [Indexed: 07/02/2024] Open
Abstract
Gamma oscillations nested in a theta rhythm are observed in the hippocampus, where are assumed to play a role in sequential episodic memory, i.e., memorization and retrieval of events that unfold in time. In this work, we present an original neurocomputational model based on neural masses, which simulates the encoding of sequences of events in the hippocampus and subsequent retrieval by exploiting the theta-gamma code. The model is based on a three-layer structure in which individual Units oscillate with a gamma rhythm and code for individual features of an episode. The first layer (working memory in the prefrontal cortex) maintains a cue in memory until a new signal is presented. The second layer (CA3 cells) implements an auto-associative memory, exploiting excitatory and inhibitory plastic synapses to recover an entire episode from a single feature. Units in this layer are disinhibited by a theta rhythm from an external source (septum or Papez circuit). The third layer (CA1 cells) implements a hetero-associative net with the previous layer, able to recover a sequence of episodes from the first one. During an encoding phase, simulating high-acetylcholine levels, the network is trained with Hebbian (synchronizing) and anti-Hebbian (desynchronizing) rules. During retrieval (low-acetylcholine), the network can correctly recover sequences from an initial cue using gamma oscillations nested inside the theta rhythm. Moreover, in high noise, the network isolated from the environment simulates a mind-wandering condition, randomly replicating previous sequences. Interestingly, in a state simulating sleep, with increased noise and reduced synapses, the network can "dream" by creatively combining sequences, exploiting features shared by different episodes. Finally, an irrational behavior (erroneous superimposition of features in various episodes, like "delusion") occurs after pathological-like reduction in fast inhibitory synapses. The model can represent a straightforward and innovative tool to help mechanistically understand the theta-gamma code in different mental states.
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Yao R, Yamada K, Izawa S, Kito T, Sawada H, Chihara T, Aizu N, Iwata D, Nishii K. FNDC5/irisin mediates the protective effects of Innovative theta-shaking exercise on mouse memory. Heliyon 2024; 10:e29090. [PMID: 38638979 PMCID: PMC11024559 DOI: 10.1016/j.heliyon.2024.e29090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Revised: 03/23/2024] [Accepted: 03/29/2024] [Indexed: 04/20/2024] Open
Abstract
As a passive motion and non-invasive treatment, theta-shaking exercise is considered an alternative to traditional active exercise for slowing down brain ageing. Here, we studied the influence of theta-shaking exercise on fibronectin type III domain containing 5/irisin (FNDC5/irisin) in the anterior nucleus of the thalamus, hippocampus, and medial prefrontal cortex (ATN-HPC-MPFC). Further, we assessed memory in senescence-accelerated prone mice (SAMP-10 mice) using a behavioural test to confirm the protective effect of theta-shaking exercise against age-related memory decline. SAMP-10 mice were subjected to theta-shaking exercise for 9-30 weeks. Mice then performed the T-maze test and passive avoidance task. Immunohistochemical analysis and ELISA were used to assess FNDC5/irisin, nerve growth factor (NGF), and neurotrophin 4/5 (NT4/5) expression in the ATN-HPC-MPFC. In the shaking group, FNDC5 was locally upregulated within the hippocampus and MPFC area rather than exhibiting even distribution throughout brain tissue. Irisin levels were generally higher in the control group. Meanwhile, hippocampal NGF levels were significantly higher in the shaking group, with no differences noted in neurotrophin levels. Theta-shaking preserved normal neurons in certain sub-regions. However, no beneficial changes in neuronal density were noted in the ATN. Theta-shaking exercise positively affects memory function in SAMP-10 mice. FNDC5 upregulation and higher levels of NGF, along with the potential involvement of irisin, may have contributed to the preservation of normal neuronal density in the hippocampus and MPFC subregions.
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Affiliation(s)
- Runhong Yao
- Physical Therapy Course, Department of Rehabilitation, Faculty of Health Sciences, Nihon Institute of Medical Science, Irumagun, Saitama 350-0435, Japan
| | - Kouji Yamada
- Graduate School of Health Sciences, Fujita Health University, Toyoake, Aichi 470-1192, Japan
| | - Sho Izawa
- Graduate School of Health Sciences, Fujita Health University, Toyoake, Aichi 470-1192, Japan
| | - Takumi Kito
- Department of Physical Therapy, Faculty of Health Sciences, Kinjo University, Hakusan, Ishikawa 924-8511, Japan
| | - Hirohide Sawada
- Department of Medical Technology, School of Nursing and Medical Care, Yokkaichi Nursing and Medical Care University, Yokkaichi, Mie 512-8045, Japan
| | - Takeshi Chihara
- Department of Medical Technology, School of Nursing and Medical Care, Yokkaichi Nursing and Medical Care University, Yokkaichi, Mie 512-8045, Japan
| | - Naoki Aizu
- Graduate School of Health Sciences, Fujita Health University, Toyoake, Aichi 470-1192, Japan
| | - Daiki Iwata
- Department of Medical Technology, School of Nursing and Medical Care, Yokkaichi Nursing and Medical Care University, Yokkaichi, Mie 512-8045, Japan
| | - Kazuhiro Nishii
- Graduate School of Health Sciences, Fujita Health University, Toyoake, Aichi 470-1192, Japan
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Dillingham CM, Wilson JJ, Vann SD. Electrophysiological Properties of the Medial Mammillary Bodies across the Sleep-Wake Cycle. eNeuro 2024; 11:ENEURO.0447-23.2024. [PMID: 38621991 PMCID: PMC11055652 DOI: 10.1523/eneuro.0447-23.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 03/19/2024] [Accepted: 03/25/2024] [Indexed: 04/17/2024] Open
Abstract
The medial mammillary bodies (MBs) play an important role in the formation of spatial memories; their dense inputs from hippocampal and brainstem regions makes them well placed to integrate movement-related and spatial information, which is then extended to the anterior thalamic nuclei and beyond to the cortex. While the anatomical connectivity of the medial MBs has been well studied, much less is known about their physiological properties, particularly in freely moving animals. We therefore carried out a comprehensive characterization of medial MB electrophysiology across arousal states by concurrently recording from the medial MB and the CA1 field of the hippocampus in male rats. In agreement with previous studies, we found medial MB neurons to have firing rates modulated by running speed and angular head velocity, as well as theta-entrained firing. We extended the characterization of MB neuron electrophysiology in three key ways: (1) we identified a subset of neurons (25%) that exhibit dominant bursting activity; (2) we showed that ∼30% of theta-entrained neurons exhibit robust theta cycle skipping, a firing characteristic that implicates them in a network for prospective coding of position; and (3) a considerable proportion of medial MB units showed sharp-wave ripple (SWR) responsive firing (∼37%). The functional heterogeneity of MB electrophysiology reinforces their role as an integrative node for mnemonic processing and identifies potential roles for the MBs in memory consolidation through propagation of SWR-responsive activity to the anterior thalamus and prospective coding in the form of theta cycle skipping.
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Affiliation(s)
- Christopher M Dillingham
- School of Psychology, Cardiff University, Cardiff CF10 3AT, United Kingdom
- Neuroscience and Mental Health Innovation Institute, Cardiff CF24 4HQ, United Kingdom
| | - Jonathan J Wilson
- School of Psychology, Cardiff University, Cardiff CF10 3AT, United Kingdom
- Neuroscience and Mental Health Innovation Institute, Cardiff CF24 4HQ, United Kingdom
| | - Seralynne D Vann
- School of Psychology, Cardiff University, Cardiff CF10 3AT, United Kingdom
- Neuroscience and Mental Health Innovation Institute, Cardiff CF24 4HQ, United Kingdom
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6
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Sikorski R, Sitek EJ. The misidentification syndromes and source memory deficits with their neuroanatomical correlates from neuropsychological perspective. Behav Brain Sci 2023; 46:e376. [PMID: 37961775 DOI: 10.1017/s0140525x23000274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
The suggested model is discussed with reference to two clinical populations with memory disorders - patients with misidentification syndromes and those with source memory impairment, both of whom may present with (broadly conceived) déjà vu phenomenon, without insight into false feeling of familiarity. The role of the anterior thalamic nucleus and retrosplenial cortex for autobiographical memory and familiarity is highlighted.
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Affiliation(s)
- Rafał Sikorski
- Laboratory of Clinical Neuropsychology, Neurolinguistics and Neuropsychotherapy, Department of Neurological and Psychiatric Nursing, Faculty of Health Sciences, Medical University of Gdansk, ul. Debinki 7, Gdansk, Poland https://structure.mug.edu.pl/520
- Department of Neurological Rehabilitation, St. Vincent Hospital, Pomeranian Hospitals, Ul. Wójta Radtkego 1, Gdynia, Poland
| | - Emilia J Sitek
- Laboratory of Clinical Neuropsychology, Neurolinguistics and Neuropsychotherapy, Department of Neurological and Psychiatric Nursing, Faculty of Health Sciences, Medical University of Gdansk, ul. Debinki 7, Gdansk, Poland https://structure.mug.edu.pl/520
- Department of Neurology, St. Adalbert Hospital, Copernicus PL, Al. Jana Pawla II 50, Gdańsk, Poland https://structure.mug.edu.pl/520
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Kamali A, Milosavljevic S, Gandhi A, Lano KR, Shobeiri P, Sherbaf FG, Sair HI, Riascos RF, Hasan KM. The Cortico-Limbo-Thalamo-Cortical Circuits: An Update to the Original Papez Circuit of the Human Limbic System. Brain Topogr 2023; 36:371-389. [PMID: 37148369 PMCID: PMC10164017 DOI: 10.1007/s10548-023-00955-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 03/06/2023] [Indexed: 05/08/2023]
Abstract
The Papez circuit, first proposed by James Papez in 1937, is a circuit believed to control memory and emotions, composed of the cingulate cortex, entorhinal cortex, parahippocampal gyrus, hippocampus, hypothalamus, and thalamus. Pursuant to James Papez, Paul Yakovlev and Paul MacLean incorporated the prefrontal/orbitofrontal cortex, septum, amygdalae, and anterior temporal lobes into the limbic system. Over the past few years, diffusion-weighted tractography techniques revealed additional limbic fiber connectivity, which incorporates multiple circuits to the already known complex limbic network. In the current review, we aimed to comprehensively summarize the anatomy of the limbic system and elaborate on the anatomical connectivity of the limbic circuits based on the published literature as an update to the original Papez circuit.
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Affiliation(s)
- Arash Kamali
- Department of Diagnostic and Interventional Radiology, Neuroradiology Section, University of Texas at Houston, 6431 Fannin St, Houston, TX, 77030, USA.
| | | | - Anusha Gandhi
- Baylor College of Medicine Medical School, Houston, TX, USA
| | - Kinsey R Lano
- McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Parnian Shobeiri
- Faculty of Medicine, Tehran University Medical School, Tehran, Iran
| | - Farzaneh Ghazi Sherbaf
- Department of Radiology and Radiological Science, Division of Neuroradiology, The Russell H. Morgan, Johns Hopkins University, Baltimore, MD, USA
| | - Haris I Sair
- Department of Radiology and Radiological Science, Division of Neuroradiology, The Russell H. Morgan, Johns Hopkins University, Baltimore, MD, USA
| | - Roy F Riascos
- Department of Diagnostic and Interventional Radiology, Neuroradiology Section, University of Texas at Houston, 6431 Fannin St, Houston, TX, 77030, USA
| | - Khader M Hasan
- Department of Diagnostic and Interventional Radiology, Neuroradiology Section, University of Texas at Houston, 6431 Fannin St, Houston, TX, 77030, USA
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Segobin S, Ambler M, Laniepce A, Platel H, Chételat G, Groussard M, Pitel AL. Korsakoff's Syndrome and Alzheimer's Disease-Commonalities and Specificities of Volumetric Brain Alterations within Papez Circuit. J Clin Med 2023; 12:jcm12093147. [PMID: 37176588 PMCID: PMC10179200 DOI: 10.3390/jcm12093147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 04/11/2023] [Accepted: 04/18/2023] [Indexed: 05/15/2023] Open
Abstract
Background: Alzheimer's disease (AD) and Korsakoff's syndrome (KS) are two major neurocognitive disorders characterized by amnesia but AD is degenerative while KS is not. The objective is to compare regional volume deficits within the Papez circuit in AD and KS, considering AD progression. Methods: 18 KS patients, 40 AD patients (20 with Moderate AD (MAD) matched on global cognitive deficits with KS patients and 20 with Severe AD (SAD)), and 70 healthy controls underwent structural MRI. Volumes of the hippocampi, thalami, cingulate gyri, mammillary bodies (MB) and mammillothalamic tracts (MTT) were extracted. Results: For the cingulate gyri, and anterior thalamic nuclei, all patient groups were affected compared to controls but did not differ between each other. Smaller volumes were observed in all patient groups compared to controls in the mediodorsal thalamic nuclei and MB, but these regions were more severely damaged in KS than AD. MTT volumes were damaged in KS only. Hippocampi were affected in all patient groups but more severely in the SAD than in the KS and MAD. Conclusions: There are commonalities in the pattern of volume deficits in KS and AD within the Papez circuit with the anterior thalamic nuclei, cingulate cortex and hippocampus (in MAD only) being damaged to the same extent. The specificity of KS relies on the alteration of the MTT and the severity of the MB shrinkage. Further comparative studies including other imaging modalities and a neuropsychological assessment are required.
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Affiliation(s)
- Shailendra Segobin
- Normandie Univ, UNICAEN, PSL Université Paris, EPHE, INSERM, U1077, CHU de Caen, Cyceron, Neuropsychologie et Imagerie de la Mémoire Humaine (NIMH), 14000 Caen, France
| | - Melanie Ambler
- Normandie Univ, UNICAEN, PSL Université Paris, EPHE, INSERM, U1077, CHU de Caen, Cyceron, Neuropsychologie et Imagerie de la Mémoire Humaine (NIMH), 14000 Caen, France
| | - Alice Laniepce
- Normandie Univ, UNICAEN, PSL Université Paris, EPHE, INSERM, U1077, CHU de Caen, Cyceron, Neuropsychologie et Imagerie de la Mémoire Humaine (NIMH), 14000 Caen, France
- Normandie Univ, UNIROUEN, CRFDP (EA 7475), 76821 Rouen, France
- Normandie Univ, UNICAEN, INSERM, PhIND "Physiopathology and Imaging of Neurological Disorders", Institut Blood and Brain @ Caen-Normandie, Cyceron, 14000 Caen, France
| | - Hervé Platel
- Normandie Univ, UNICAEN, PSL Université Paris, EPHE, INSERM, U1077, CHU de Caen, Cyceron, Neuropsychologie et Imagerie de la Mémoire Humaine (NIMH), 14000 Caen, France
| | - Gael Chételat
- Normandie Univ, UNICAEN, INSERM, PhIND "Physiopathology and Imaging of Neurological Disorders", Institut Blood and Brain @ Caen-Normandie, Cyceron, 14000 Caen, France
| | - Mathilde Groussard
- Normandie Univ, UNICAEN, PSL Université Paris, EPHE, INSERM, U1077, CHU de Caen, Cyceron, Neuropsychologie et Imagerie de la Mémoire Humaine (NIMH), 14000 Caen, France
| | - Anne-Lise Pitel
- Normandie Univ, UNICAEN, INSERM, PhIND "Physiopathology and Imaging of Neurological Disorders", Institut Blood and Brain @ Caen-Normandie, Cyceron, 14000 Caen, France
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Collins SC, Vancollie VE, Mikhaleva A, Wagner C, Balz R, Lelliott CJ, Yalcin B. Characterization of Two Mouse Chd7 Heterozygous Loss-of-Function Models Shows Dysgenesis of the Corpus Callosum and Previously Unreported Features of CHARGE Syndrome. Int J Mol Sci 2022; 23:11509. [PMID: 36232804 PMCID: PMC9569499 DOI: 10.3390/ijms231911509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 09/22/2022] [Accepted: 09/27/2022] [Indexed: 11/16/2022] Open
Abstract
CHARGE syndrome is a rare congenital disorder frequently caused by mutations in the chromodomain helicase DNA-binding protein-7 CHD7. Here, we developed and systematically characterized two genetic mouse models with identical, heterozygous loss-of-function mutation of the Chd7 gene engineered on inbred and outbred genetic backgrounds. We found that both models showed consistent phenotypes with the core clinical manifestations seen in CHARGE syndrome, but the phenotypes in the inbred Chd7 model were more severe, sometimes having reduced penetrance and included dysgenesis of the corpus callosum, hypoplasia of the hippocampus, abnormal retrosplenial granular cortex, ventriculomegaly, hyperactivity, growth delays, impaired grip strength and repetitive behaviors. Interestingly, we also identified previously unreported features including reduced levels of basal insulin and reduced blood lipids. We suggest that the phenotypic variation reported in individuals diagnosed with CHARGE syndrome is likely due to the genetic background and modifiers. Finally, our study provides a valuable resource, making it possible for mouse biologists interested in Chd7 to make informed choices on which mouse model they should use to study phenotypes of interest and investigate in more depth the underlying cellular and molecular mechanisms.
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Affiliation(s)
- Stephan C. Collins
- Inserm UMR1231, University of Burgundy Franche-Comté, 15 Boulevard Maréchal de Lattre de Tassigny, 21070 Dijon, France
| | | | - Anna Mikhaleva
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland
| | - Christel Wagner
- Institute of Genetics and Molecular and Cellular Biology, UMR7104, 67400 Illkirch, France
| | - Rebecca Balz
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland
| | | | - Binnaz Yalcin
- Inserm UMR1231, University of Burgundy Franche-Comté, 15 Boulevard Maréchal de Lattre de Tassigny, 21070 Dijon, France
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Dong R, Lv P, Han Y, Jiang L, Wang Z, Peng L, Ma Z, Xia T, Zhang B, Gu X. Enhancement of astrocytic gap junctions Connexin43 coupling can improve long-term isoflurane anesthesia-mediated brain network abnormalities and cognitive impairment. CNS Neurosci Ther 2022; 28:2281-2297. [PMID: 36153812 PMCID: PMC9627365 DOI: 10.1111/cns.13974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 08/31/2022] [Accepted: 09/03/2022] [Indexed: 02/06/2023] Open
Abstract
AIM Astrocytes are connected by gap junctions Connexin43 (GJs-Cx43) forming an extensive intercellular network and maintain brain homeostasis. Perioperative neurocognitive disorder (PND) occurs frequently after anesthesia/surgery and worsens patient outcome, but the neural circuit mechanisms remain unclear. This study aimed to determine the effects of the GJs-Cx43-mediated astrocytic network on PND and ascertain the underlying neural circuit mechanism. METHODS Male C57BL/6 mice were treated with long-term isoflurane exposure to construct a mouse model of PND. We also exposed primary mouse astrocytes to long-term isoflurane exposure to simulate the conditions of in vivo cognitive dysfunction. Behavioral tests were performed using the Y-maze and fear conditioning (FC) tests. Manganese-enhanced magnetic resonance imaging (MEMRI) and resting-state functional magnetic resonance imaging (rs-fMRI) were used to investigate brain activity and functional connectivity. Western blot and flow cytometry analysis were used to assess protein expression. RESULTS Reconfiguring the astrocytic network by increasing GJs-Cx43 expression can modulate 22 subregions affected by PND in three ways: reversed activation, reversed inhibition, and intensified activation. The brain functional connectivity analysis further suggests that PND is a brain network disorder that includes sleep-wake rhythm-related brain regions, contextual and fear memory-related subregions, the hippocampal-amygdala circuit, the septo-hippocampal circuit, and the entorhinal-hippocampal circuit. Notably, remodeling the astrocytic network by upregulation of GJs-Cx43 can partially reverse the abnormalities in the above circuits. Pathophysiological degeneration in hippocampus is one of the primary hallmarks of PND pathology, and long-term isoflurane anesthesia contributes to oxidative stress and neuroinflammation in the hippocampus. However, promoting the formation of GJs-Cx43 ameliorated cognitive dysfunction induced by long-term isoflurane anesthesia through the attenuation of oxidative stress in hippocampus. CONCLUSION Enhancing GJs-Cx43 coupling can improve brain network abnormalities and cognitive impairment induced by long-term isoflurane anesthesia, its mechanisms might be associated with the regulation of oxidative stress and neuroinflammation.
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Affiliation(s)
- Rui Dong
- Department of AnesthesiologyThe Affiliated Drum Tower Hospital of Nanjing University Medical SchoolNanjingChina
| | - Pin Lv
- Department of RadiologyThe Affiliated Drum Tower Hospital of Nanjing University Medical SchoolNanjingChina
| | - Yuqiang Han
- Department of AnesthesiologyThe Affiliated Drum Tower Hospital of Nanjing University Medical SchoolNanjingChina
| | - Linhao Jiang
- Department of AnesthesiologyThe Affiliated Drum Tower Hospital of Nanjing University Medical SchoolNanjingChina
| | - Zimo Wang
- Department of AnesthesiologyThe Affiliated Drum Tower Hospital of Nanjing University Medical SchoolNanjingChina
| | - Liangyu Peng
- Department of AnesthesiologyThe Affiliated Drum Tower Hospital of Nanjing University Medical SchoolNanjingChina
| | - Zhengliang Ma
- Department of AnesthesiologyThe Affiliated Drum Tower Hospital of Nanjing University Medical SchoolNanjingChina
| | - Tianjiao Xia
- Medical SchoolNanjing UniversityNanjingChina,Jiangsu Key Laboratory of Molecular MedicineNanjingChina
| | - Bing Zhang
- Department of RadiologyThe Affiliated Drum Tower Hospital of Nanjing University Medical SchoolNanjingChina,Jiangsu Key Laboratory of Molecular MedicineNanjingChina,Institute of Medical Imaging and Artificial IntelligenceNanjing UniversityNanjingChina,Institute of Brain ScienceNanjing UniversityNanjingChina
| | - Xiaoping Gu
- Department of AnesthesiologyThe Affiliated Drum Tower Hospital of Nanjing University Medical SchoolNanjingChina
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11
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Hoch MJ, Shepherd TM. MRI-Visible Anatomy of the Basal Ganglia and Thalamus. Neuroimaging Clin N Am 2022; 32:529-541. [PMID: 35843660 DOI: 10.1016/j.nic.2022.05.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Conventional MR imaging does not discriminate basal ganglia and thalamic internal anatomy well. Radiology reports describe anatomic locations but not specific functional structures. Functional neurosurgery uses indirect targeting based on commissural coordinates or atlases that do not fully account for individual variability. We describe innovative MR imaging sequences that improve the visualization of normal anatomy in this complex brain region and may increase our understanding of basal ganglia and thalamic function. Better visualization also may improve treatments for movement disorders and other emerging functional neurosurgery targets. We aim to provide an accessible review of the most clinically-relevant neuroanatomy within the thalamus and basal ganglia.
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Affiliation(s)
- Michael J Hoch
- Department of Radiology, University of Pennsylvania, 3400 Spruce Street, Suite 130, Philadelphia, PA 19104, USA. https://twiter.com/@RVUhound
| | - Timothy M Shepherd
- Department of Radiology, New York University Langone School of Medicine, 660 First Avenue, Room 226, New York, NY 10016, USA.
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Cassel JC, de Vasconcelos AP. The thalamus: A long journey through successive translations (Editorial to the special issue entitled 'The Cognitive Thalamus'). Neurosci Biobehav Rev 2022; 140:104779. [PMID: 35868523 DOI: 10.1016/j.neubiorev.2022.104779] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Affiliation(s)
- Jean-Christophe Cassel
- Laboratoire de Neurosciences Cognitives et Adaptatives, Université de Strasbourg, F-67000 Strasbourg, France; LNCA, UMR 7364 - CNRS, F-67000 Strasbourg, France
| | - Anne Pereira de Vasconcelos
- Laboratoire de Neurosciences Cognitives et Adaptatives, Université de Strasbourg, F-67000 Strasbourg, France; LNCA, UMR 7364 - CNRS, F-67000 Strasbourg, France
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Ursino M, Cesaretti N, Pirazzini G. A model of working memory for encoding multiple items and ordered sequences exploiting the theta-gamma code. Cogn Neurodyn 2022; 17:489-521. [PMID: 37007198 PMCID: PMC10050512 DOI: 10.1007/s11571-022-09836-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2021] [Revised: 02/25/2022] [Accepted: 05/27/2022] [Indexed: 11/24/2022] Open
Abstract
AbstractRecent experimental evidence suggests that oscillatory activity plays a pivotal role in the maintenance of information in working memory, both in rodents and humans. In particular, cross-frequency coupling between theta and gamma oscillations has been suggested as a core mechanism for multi-item memory. The aim of this work is to present an original neural network model, based on oscillating neural masses, to investigate mechanisms at the basis of working memory in different conditions. We show that this model, with different synapse values, can be used to address different problems, such as the reconstruction of an item from partial information, the maintenance of multiple items simultaneously in memory, without any sequential order, and the reconstruction of an ordered sequence starting from an initial cue. The model consists of four interconnected layers; synapses are trained using Hebbian and anti-Hebbian mechanisms, in order to synchronize features in the same items, and desynchronize features in different items. Simulations show that the trained network is able to desynchronize up to nine items without a fixed order using the gamma rhythm. Moreover, the network can replicate a sequence of items using a gamma rhythm nested inside a theta rhythm. The reduction in some parameters, mainly concerning the strength of GABAergic synapses, induce memory alterations which mimic neurological deficits. Finally, the network, isolated from the external environment (“imagination phase”) and stimulated with high uniform noise, can randomly recover sequences previously learned, and link them together by exploiting the similarity among items.
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Affiliation(s)
- Mauro Ursino
- Department of Electrical, Electronic and Information Engineering “Guglielmo Marconi”, University of Bologna, Campus of Cesena Area di Campus Cesena Via Dell’Università 50, 47521 Cesena, FC Italy
| | - Nicole Cesaretti
- Department of Electrical, Electronic and Information Engineering “Guglielmo Marconi”, University of Bologna, Campus of Cesena Area di Campus Cesena Via Dell’Università 50, 47521 Cesena, FC Italy
| | - Gabriele Pirazzini
- Department of Electrical, Electronic and Information Engineering “Guglielmo Marconi”, University of Bologna, Campus of Cesena Area di Campus Cesena Via Dell’Università 50, 47521 Cesena, FC Italy
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14
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McNaughton N, Vann SD. Construction of complex memories via parallel distributed cortical-subcortical iterative integration. Trends Neurosci 2022; 45:550-562. [PMID: 35599065 PMCID: PMC7612902 DOI: 10.1016/j.tins.2022.04.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 04/01/2022] [Accepted: 04/22/2022] [Indexed: 01/08/2023]
Abstract
The construction of complex engrams requires hippocampal-cortical interactions. These include both direct interactions and ones via often-overlooked subcortical loops. Here, we review the anatomical organization of a hierarchy of parallel 'Papez' loops through the hypothalamus that are homologous in mammals from rats to humans. These hypothalamic loops supplement direct hippocampal-cortical connections with iterative reprocessing paced by theta rhythmicity. We couple existing anatomy and lesion data with theory to propose that recirculation in these loops progressively enhances desired connections, while reducing interference from competing external goals and internal associations. This increases the signal-to-noise ratio in the distributed engrams (neocortical and cerebellar) necessary for complex learning and memory. The hypothalamic nodes provide key motivational input for engram enhancement during consolidation.
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Affiliation(s)
- Neil McNaughton
- Department of Psychology and Brain Health Research Centre, University of Otago, POB56, Dunedin, New Zealand.
| | - Seralynne D Vann
- School of Psychology, Cardiff University, Park Place, Cardiff, CF10 3AT, UK.
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15
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Meys KME, de Vries LS, Groenendaal F, Vann SD, Lequin MH. The Mammillary Bodies: A Review of Causes of Injury in Infants and Children. AJNR Am J Neuroradiol 2022; 43:802-812. [PMID: 35487586 PMCID: PMC9172959 DOI: 10.3174/ajnr.a7463] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 11/22/2021] [Indexed: 12/20/2022]
Abstract
Despite their small size, the mammillary bodies play an important role in supporting recollective memory. However, they have typically been overlooked when assessing neurologic conditions that present with memory impairment. While there is increasing evidence of mammillary body involvement in a wide range of neurologic disorders in adults, very little attention has been given to infants and children. Literature searches of PubMed and EMBASE were performed to identify articles that describe mammillary body pathology on brain MR imaging in children. Mammillary body pathology is present in the pediatric population in several conditions, indicated by signal change and/or atrophy on MR imaging. The main causes of mammillary body pathology are thiamine deficiency, hypoxia-ischemia, direct damage due to masses or hydrocephalus, or deafferentation resulting from pathology within the wider Papez circuit. Optimizing scanning protocols and assessing mammillary body status as a standard procedure are critical, given their role in memory processes.
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Affiliation(s)
- K M E Meys
- From the Department of Radiology (K.M.E.M., F.G., M.H.L.), Wilhelmina Children's Hospital, University Medical Center Utrecht and Utrecht University, Utrecht, Netherlands
| | - L S de Vries
- Department of Neonatology (L.S.D.V.), Wilhelmina Children's Hospital, University Medical Center Utrecht and Utrecht University, Utrecht, Netherlands
| | - F Groenendaal
- From the Department of Radiology (K.M.E.M., F.G., M.H.L.), Wilhelmina Children's Hospital, University Medical Center Utrecht and Utrecht University, Utrecht, Netherlands
| | - S D Vann
- School of Psychology (S.D.V.), Cardiff University, Cardiff, UK
| | - M H Lequin
- From the Department of Radiology (K.M.E.M., F.G., M.H.L.), Wilhelmina Children's Hospital, University Medical Center Utrecht and Utrecht University, Utrecht, Netherlands
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16
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The anterior thalamic nuclei: core components of a tripartite episodic memory system. Nat Rev Neurosci 2022; 23:505-516. [PMID: 35478245 DOI: 10.1038/s41583-022-00591-8] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/25/2022] [Indexed: 12/13/2022]
Abstract
Standard models of episodic memory focus on hippocampal-parahippocampal interactions, with the neocortex supplying sensory information and providing a final repository of mnemonic representations. However, recent advances have shown that other regions make distinct and equally critical contributions to memory. In particular, there is growing evidence that the anterior thalamic nuclei have a number of key cognitive functions that support episodic memory. In this article, we describe these findings and argue for a core, tripartite memory system, comprising a 'temporal lobe' stream (centred on the hippocampus) and a 'medial diencephalic' stream (centred on the anterior thalamic nuclei) that together act on shared cortical areas. We demonstrate how these distributed brain regions form complementary and necessary partnerships in episodic memory formation.
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17
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Keshavarzi S, Bracey EF, Faville RA, Campagner D, Tyson AL, Lenzi SC, Branco T, Margrie TW. Multisensory coding of angular head velocity in the retrosplenial cortex. Neuron 2021; 110:532-543.e9. [PMID: 34788632 PMCID: PMC8823706 DOI: 10.1016/j.neuron.2021.10.031] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 07/29/2021] [Accepted: 10/20/2021] [Indexed: 01/05/2023]
Abstract
To successfully navigate the environment, animals depend on their ability to continuously track their heading direction and speed. Neurons that encode angular head velocity (AHV) are fundamental to this process, yet the contribution of various motion signals to AHV coding in the cortex remains elusive. By performing chronic single-unit recordings in the retrosplenial cortex (RSP) of the mouse and tracking the activity of individual AHV cells between freely moving and head-restrained conditions, we find that vestibular inputs dominate AHV signaling. Moreover, the addition of visual inputs onto these neurons increases the gain and signal-to-noise ratio of their tuning during active exploration. Psychophysical experiments and neural decoding further reveal that vestibular-visual integration increases the perceptual accuracy of angular self-motion and the fidelity of its representation by RSP ensembles. We conclude that while cortical AHV coding requires vestibular input, where possible, it also uses vision to optimize heading estimation during navigation. Angular head velocity (AHV) coding is widespread in the retrosplenial cortex (RSP) AHV cells maintain their tuning during passive motion and require vestibular input The perception of angular self-motion is improved when visual cues are present AHV coding is similarly improved when both vestibular and visual stimuli are used
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Affiliation(s)
- Sepiedeh Keshavarzi
- Sainsbury Wellcome Centre for Neural Circuits and Behaviour, University College London (UCL), 25 Howland Street, London W1T 4JG, United Kingdom.
| | - Edward F Bracey
- Sainsbury Wellcome Centre for Neural Circuits and Behaviour, University College London (UCL), 25 Howland Street, London W1T 4JG, United Kingdom
| | - Richard A Faville
- Sainsbury Wellcome Centre for Neural Circuits and Behaviour, University College London (UCL), 25 Howland Street, London W1T 4JG, United Kingdom
| | - Dario Campagner
- Sainsbury Wellcome Centre for Neural Circuits and Behaviour, University College London (UCL), 25 Howland Street, London W1T 4JG, United Kingdom; Gatsby Computational Neuroscience Unit, University College London (UCL), 25 Howland Street, London W1T 4JG, United Kingdom
| | - Adam L Tyson
- Sainsbury Wellcome Centre for Neural Circuits and Behaviour, University College London (UCL), 25 Howland Street, London W1T 4JG, United Kingdom
| | - Stephen C Lenzi
- Sainsbury Wellcome Centre for Neural Circuits and Behaviour, University College London (UCL), 25 Howland Street, London W1T 4JG, United Kingdom
| | - Tiago Branco
- Sainsbury Wellcome Centre for Neural Circuits and Behaviour, University College London (UCL), 25 Howland Street, London W1T 4JG, United Kingdom
| | - Troy W Margrie
- Sainsbury Wellcome Centre for Neural Circuits and Behaviour, University College London (UCL), 25 Howland Street, London W1T 4JG, United Kingdom.
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18
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Ma KY, Cai XY, Wang XT, Wang ZX, Huang WM, Wu ZY, Feng ZY, Shen Y. Three-Dimensional Heterogeneity of Cerebellar Interposed Nucleus-Recipient Zones in the Thalamic Nuclei. Neurosci Bull 2021; 37:1529-1541. [PMID: 34609736 DOI: 10.1007/s12264-021-00780-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 07/19/2021] [Indexed: 11/29/2022] Open
Abstract
The cerebellum is conceptualized as a processor of complex movements and is also endowed with roles in cognitive and emotional behaviors. Although the axons of deep cerebellar nuclei are known to project to primary thalamic nuclei, macroscopic investigation of the characteristics of these projections, such as the spatial distribution of recipient zones, is lacking. Here, we studied the output of the cerebellar interposed nucleus (IpN) to the ventrolateral (VL) and centrolateral (CL) thalamic nuclei using electrophysiological recording in vivo and trans-synaptic viral tracing. We found that IpN stimulation induced mono-synaptic evoked potentials (EPs) in the VL but not the CL region. Furthermore, both the EPs induced by the IpN and the innervation of IpN projections displayed substantial heterogeneity across the VL region in three-dimensional space. These findings indicate that the recipient zones of IpN inputs vary between and within thalamic nuclei and may differentially control thalamo-cortical networks.
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Affiliation(s)
- Kuang-Yi Ma
- Department of Physiology and Department of Neurology of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Xin-Yu Cai
- Department of Physiology and Department of Neurology of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Xin-Tai Wang
- Department of Physiology and Department of Neurology of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Zhao-Xiang Wang
- Key Laboratory of Biomedical Engineering of the Ministry of Education, College of Biomedical Engineering and Instrumentation Science, Zhejiang University, Hangzhou, 310013, China
| | - Wan-Meng Huang
- Department of Physiology and Department of Neurology of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Zhi-Ying Wu
- Department of Neurology and Research Center of Neurology in the Second Affiliated Hospital, and Key Laboratory of Medical Neurobiology of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Zhou-Yan Feng
- Key Laboratory of Biomedical Engineering of the Ministry of Education, College of Biomedical Engineering and Instrumentation Science, Zhejiang University, Hangzhou, 310013, China
| | - Ying Shen
- Department of Physiology and Department of Neurology of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310058, China.
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19
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Understanding the Significance of the Hypothalamic Nature of the Subthalamic Nucleus. eNeuro 2021; 8:ENEURO.0116-21.2021. [PMID: 34518367 PMCID: PMC8493884 DOI: 10.1523/eneuro.0116-21.2021] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 08/05/2021] [Accepted: 08/20/2021] [Indexed: 11/21/2022] Open
Abstract
The subthalamic nucleus (STN) is an essential component of the basal ganglia and has long been considered to be a part of the ventral thalamus. However, recent neurodevelopmental data indicated that this nucleus is of hypothalamic origin which is now commonly acknowledged. In this work, we aimed to verify whether the inclusion of the STN in the hypothalamus could influence the way we understand and conduct research on the organization of the whole ventral and posterior diencephalon. Developmental and neurochemical data indicate that the STN is part of a larger glutamatergic posterior hypothalamic region that includes the premammillary and mammillary nuclei. The main anatomic characteristic common to this region involves the convergent cortical and pallidal projections that it receives, which is based on the model of the hyperdirect and indirect pathways to the STN. This whole posterior hypothalamic region is then integrated into distinct functional networks that interact with the ventral mesencephalon to adjust behavior depending on external and internal contexts.
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20
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Perez FA, Elfers C, Yanovski JA, Shoemaker AH, Abuzzahab MJ, Roth CL. MRI measures of hypothalamic injury are associated with glucagon-like peptide-1 receptor agonist treatment response in people with hypothalamic obesity. Diabetes Obes Metab 2021; 23:1532-1541. [PMID: 33651438 PMCID: PMC8353597 DOI: 10.1111/dom.14366] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 02/15/2021] [Accepted: 02/26/2021] [Indexed: 12/13/2022]
Abstract
AIM To evaluate whether neuroimaging-delineated regions of hypothalamic injury are associated with a differential treatment response to a glucagon-like peptide-1 receptor agonist (GLP-1RA) in patients with hypothalamic obesity (HO). MATERIALS AND METHODS We performed a prespecified secondary analysis of a randomized, multicentre, double-blind, placebo-controlled trial of people aged 10-25 years with hypothalamic injury and HO randomized to the GLP-1RA exenatide once-weekly (ExQW) or placebo for 36 weeks. Subjects underwent MRI prior to enrolment and the degree of hypothalamic damage was assessed using an integrative hypothalamic lesion score (HLS). Mammillary body (MB) damage was specifically determined. The main clinical endpoints were % change in body mass index (BMI) and change in % body fat. Nested ANCOVA models including a treatment × imaging measure interaction were compared using partial F-tests to assess whether the effect of ExQW treatment differed by severity of hypothalamic damage. RESULTS Complete data were available in 35/42 randomized participants (placebo, n = 15; ExQW, n = 20). ExQW-treated patients with worse HLS or bilateral MB damage had greater reductions in % body fat at 36 weeks (interaction coefficient estimates for HLS: -0.9%, 95% CI -1.6% to -0.2%, p = .02; for MB damage: -7.4%, 95% CI -10.1% to -4.7%, p < .001, respectively) but not for BMI % change. Similarly, patients with more damaged and smaller MB cross-sectional areas had greater reductions in % body fat following ExQW (interaction coefficient estimate 0.3%, 95% CI 0.2%-0.4%, p < .001). CONCLUSIONS In people with HO, greater hypothalamic damage as determined by MRI, in particular MB injury, is associated with greater reductions in adiposity following GLP-1RA treatment.
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Affiliation(s)
- Francisco A. Perez
- Department of Radiology, Seattle Children’s and University of Washington, Seattle, WA 98105
| | - Clinton Elfers
- Seattle Children’s Research Institute, 1900 Ninth Ave, Seattle, WA 98101
| | - Jack A. Yanovski
- Section on Growth and Obesity, Division of Intramural Research, Eunice Kennedy Shriver National, Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892
| | - Ashley H. Shoemaker
- Vanderbilt University Medical Center, Division of Pediatric Endocrinology, Nashville, TN 37212
| | - M. Jennifer Abuzzahab
- McNeely Pediatric Diabetes Center and Endocrinology Clinic, Children’s Minnesota, St. Paul, MN
| | - Christian L. Roth
- Seattle Children’s Research Institute, 1900 Ninth Ave, Seattle, WA 98101
- Department of Pediatrics, University of Washington, 1959 NE Pacific St, Seattle, WA 98195
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21
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Barnett S, Parr-Brownlie L, Perry B, Young C, Wicky H, Hughes S, McNaughton N, Dalrymple-Alford J. Anterior thalamic nuclei neurons sustain memory. CURRENT RESEARCH IN NEUROBIOLOGY 2021; 2:100022. [PMID: 36246504 PMCID: PMC9559952 DOI: 10.1016/j.crneur.2021.100022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 08/26/2021] [Accepted: 09/20/2021] [Indexed: 12/27/2022] Open
Abstract
A hippocampal-diencephalic-cortical network supports memory function. The anterior thalamic nuclei (ATN) form a key anatomical hub within this system. Consistent with this, injury to the mammillary body-ATN axis is associated with examples of clinical amnesia. However, there is only limited and indirect support that the output of ATN neurons actively enhances memory. Here, in rats, we first showed that mammillothalamic tract (MTT) lesions caused a persistent impairment in spatial working memory. MTT lesions also reduced rhythmic electrical activity across the memory system. Next, we introduced 8.5 Hz optogenetic theta-burst stimulation of the ATN glutamatergic neurons. The exogenously-triggered, regular pattern of stimulation produced an acute and substantial improvement of spatial working memory in rats with MTT lesions and enhanced rhythmic electrical activity. Neither behaviour nor rhythmic activity was affected by endogenous stimulation derived from the dorsal hippocampus. Analysis of immediate early gene activity, after the rats foraged for food in an open field, showed that exogenously-triggered ATN stimulation also increased Zif268 expression across memory-related structures. These findings provide clear evidence that increased ATN neuronal activity supports memory. They suggest that ATN-focused gene therapy may be feasible to counter clinical amnesia associated with dysfunction in the mammillary body-ATN axis. The mammillothalamic tract (MTT) supports neural activity in an extended memory system. Optogenetic activation of neurons in the anterior thalamus acutely improves memory after MTT lesions. Rescued memory associates with system-wide neuronal activation and enhanced EEG. Anterior thalamus actively sustains memory and is a feasible therapeutic target.
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