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Comparison of histological delineations of medial temporal lobe cortices by four independent neuroanatomy laboratories Hippocampus (IF 3.5) Pub Date : 2024-02-28 Anika Wuestefeld, Hannah Baumeister, Jenna N. Adams, Robin de Flores, Carl J. Hodgetts, Negar Mazloum‐Farzaghi, Rosanna K. Olsen, Vyash Puliyadi, Tammy T. Tran, Arnold Bakker, Kelsey L. Canada, Marshall A. Dalton, Ana M. Daugherty, Renaud La Joie, Lei Wang, Madigan L. Bedard, Esther Buendia, Eunice Chung, Amanda Denning, María del Mar Arroyo‐Jiménez, Emilio Artacho‐Pérula, David J. Irwin, Ranjit Ittyerah
The medial temporal lobe (MTL) cortex, located adjacent to the hippocampus, is crucial for memory and prone to the accumulation of certain neuropathologies such as Alzheimer's disease neurofibrillary tau tangles. The MTL cortex is composed of several subregions which differ in their functional and cytoarchitectonic features. As neuroanatomical schools rely on different cytoarchitectonic definitions
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Distinct engrams control fear and extinction memory Hippocampus (IF 3.5) Pub Date : 2024-02-23 Jordana Griebler Luft, Bruno Popik, Débora Aguirre Gonçalves, Fabio Cardoso Cruz, Lucas de Oliveira Alvares
Memories are stored in engram cells, which are necessary and sufficient for memory recall. Recalling a memory might undergo reconsolidation or extinction. It has been suggested that the original memory engram is reactivated during reconsolidation so that memory can be updated. Conversely, during extinction training, a new memory is formed that suppresses the original engram. Nonetheless, it is unknown
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Distinct roles of Bdnf I and Bdnf IV transcript variant expression in hippocampal neurons Hippocampus (IF 3.5) Pub Date : 2024-02-16 Svitlana V. Bach, Allison J. Bauman, Darya Hosein, Jennifer J. Tuscher, Lara Ianov, Kelsey M. Greathouse, Benjamin W. Henderson, Jeremy H. Herskowitz, Keri Martinowich, Jeremy J. Day
Brain-derived neurotrophic factor (Bdnf) plays a critical role in brain development, dendritic growth, synaptic plasticity, as well as learning and memory. The rodent Bdnf gene contains nine 5′ non-coding exons (I–IXa), which are spliced to a common 3′ coding exon (IX). Transcription of individual Bdnf variants, which all encode the same BDNF protein, is initiated at unique promoters upstream of each
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Medial positioning of the hippocampus and hippocampal fissure volume in developmental topographical disorientation Hippocampus (IF 3.5) Pub Date : 2024-01-12 Agustina Fragueiro, Claire Cury, Federica Santacroce, Ford Burles, Giuseppe Iaria, Giorgia Committeri
Developmental topographical disorientation (DTD) refers to the lifelong inability to orient by means of cognitive maps in familiar surroundings despite otherwise well-preserved general cognitive functions, and the absence of any acquired brain injury or neurological condition. While reduced functional connectivity between the hippocampus and other brain regions has been reported in DTD individuals
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Impaired perceptual discrimination of complex objects in older adults at risk for dementia Hippocampus (IF 3.5) Pub Date : 2024-01-08 Lydia Jiang, Jessica Robin, Nathanael Shing, Negar Mazloum-Farzaghi, Natalia Ladyka-Wojcik, Niroja Balakumar, Nicole D. Anderson, Jennifer D. Ryan, Morgan D. Barense, Rosanna K. Olsen
Tau pathology accumulates in the perirhinal cortex (PRC) of the medial temporal lobe (MTL) during the earliest stages of the Alzheimer's disease (AD), appearing decades before clinical diagnosis. Here, we leveraged perceptual discrimination tasks that target PRC function to detect subtle cognitive impairment even in nominally healthy older adults. Older adults who did not have a clinical diagnosis
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The analysis of H.M.'s brain: A brief review of status and plans for future studies and tissue archive Hippocampus (IF 3.5) Pub Date : 2024-01-08 David G. Amaral, Jean Augustinack, Helen Barbas, Matthew Frosch, John Gabrieli, Jennifer Luebke, Pasko Rakic, Douglas Rosene, Richard J. Rushmore
The famous amnesic patient Henry Molaison (H.M.) died on December 2, 2008. After extensive in situ magnetic resonance imaging in Boston, his brain was removed at autopsy and transported to the University of California San Diego. There the brain was prepared for frozen sectioning and cut into 2401, 70 μm coronal slices. While preliminary analyses of the brain sections have been reported, a comprehensive
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Comparison of head direction cell firing characteristics across thalamo-parahippocampal circuitry Hippocampus (IF 3.5) Pub Date : 2024-01-04 Benjamin J. Clark, Patrick A. LaChance, Shawn S. Winter, Max L. Mehlman, Will Butler, Ariyana LaCour, Jeffrey S. Taube
Head direction (HD) cells, which fire persistently when an animal's head is pointed in a particular direction, are widely thought to underlie an animal's sense of spatial orientation and have been identified in several limbic brain regions. Robust HD cell firing is observed throughout the thalamo-parahippocampal system, although recent studies report that parahippocampal HD cells exhibit distinct firing
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Effects of healthy aging and mnemonic strategies on verbal memory performance across the adult lifespan: Mediating role of posterior hippocampus Hippocampus (IF 3.5) Pub Date : 2023-12-25 Kim Ngan Hoang, Yushan Huang, Esther Fujiwara, Nikolai Malykhin
In this study, we aimed to understand the contributions of hippocampal anteroposterior subregions (head, body, tail) and subfields (cornu ammonis 1-3 [CA1-3], dentate gyrus [DG], and subiculum [Sub]) and encoding strategies to the age-related verbal memory decline. Healthy participants were administered the California Verbal Learning Test-II to evaluate verbal memory performance and encoding strategies
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Knockout of NMDARs in CA1 and dentate gyrus fails to impair temporal control of conditioned behavior in mice Hippocampus (IF 3.5) Pub Date : 2023-12-22 Jasmin A. Strickland, Joseph M. Austen, Rolf Sprengel, David J. Sanderson
The hippocampus has been implicated in temporal learning. Plasticity within the hippocampus requires NMDA receptor-dependent glutamatergic neurotransmission. We tested the prediction that hippocampal NMDA receptors are required for learning about time by testing mice that lack postembryonal NMDARs in the CA1 and dentate gyrus (DG) hippocampal subfields on three different appetitive temporal learning
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Hippocampal parvalbumin and perineuronal nets: Possible involvement in anxiety-like behavior in rats Hippocampus (IF 3.5) Pub Date : 2023-12-15 Zhixin Fan, Xiayu Gong, Hanfang Xu, Yue Qu, Bozhi Li, Lanxin Li, Yuqi Yan, Lili Wu, Can Yan
The excitatory-inhibitory imbalance has been considered an important mechanism underlying stress-related psychiatric disorders. In the present study, rats were exposed to 6 days of inescapable foot shock (IFS) to induce stress. The open field test and elevated plus maze test showed that IFS-exposed rats exhibited increased anxiety-like behavior. Immunofluorescence showed that IFS rats had a decreased
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The medial prefrontal cortex during flexible decisions: Evidence for its role in distinct working memory processes Hippocampus (IF 3.5) Pub Date : 2023-12-14 Kevan Kidder, Ryan Gillis, Jesse Miles, Sheri J. Y. Mizumori
During decisions that involve working memory, task-related information must be encoded, maintained across delays, and retrieved. Few studies have attempted to causally disambiguate how different brain structures contribute to each of these components of working memory. In the present study, we used transient optogenetic disruptions of rat medial prefrontal cortex (mPFC) during a serial spatial reversal
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Object-place-context learning impairment correlates with spatial learning impairment in aged Long–Evans rats Hippocampus (IF 3.5) Pub Date : 2023-12-11 Yuxi Chen, Audrey Branch, Cecelia Shuai, Michela Gallagher, James J. Knierim
The hippocampal formation is vulnerable to the process of normal aging. In humans, the extent of this age-related deterioration varies among individuals. Long–Evans rats replicate these individual differences as they age, and therefore they serve as a valuable model system to study aging in the absence of neurodegenerative diseases. In the Morris water maze, aged memory-unimpaired (AU) rats navigate
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Impacted spike frequency adaptation associated with reduction of KCNQ2/3 exacerbates seizure activity in temporal lobe epilepsy Hippocampus (IF 3.5) Pub Date : 2023-12-04 Shicheng Jiang, Bei Liu, Kaiwen Lin, Lianjun Li, Rongrong Li, Shuo Tan, Xinyu Zhang, Lei Jiang, Hong Ni, Yuanyuan Wang, Haihu Ding, Jing Hu, Hao Qian, Rongjing Ge
Numerous epilepsy-related genes have been identified in recent decades by unbiased genome-wide screens. However, the available druggable targets for temporal lobe epilepsy (TLE) remain limited. Furthermore, a substantial pool of candidate genes potentially applicable to TLE therapy awaits further validation. In this study, we reveal the significant role of KCNQ2 and KCNQ3, two M-type potassium channel
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A configural context signal simultaneously but separably drives positioning and orientation of hippocampal place fields Hippocampus (IF 3.5) Pub Date : 2023-12-02 Han Yin Cheng, Dorothy W. Overington, Kate J. Jeffery
Effective self-localization requires that the brain can resolve ambiguities in incoming sensory information arising from self-similarities (symmetries) in the environment structure. We investigated how place cells use environmental cues to resolve the ambiguity of a rotationally symmetric environment, by recording from hippocampal CA1 in rats exploring a “2-box.” This apparatus comprises two adjacent
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Correction to “A complex relation between levels of adult hippocampal neurogenesis and expression of the immature neuron marker doublecortin” Hippocampus (IF 3.5) Pub Date : 2023-11-30
Mendez-David, I., David, D. J., Deloménie, C., Tritschler, L., Beaulieu, J.-M., Colle, R., Corruble, E., Gardier, A. M., & Hen, R. (2023). A complex relation between levels of adult hippocampal neurogenesis and expression of the immature neuron marker doublecortin. Hippocampus, 33(10), 1075–1093. https://doi.org/10.1002/hipo.23568 In the originally published version of the article, Laurent Tritschler
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Computational models can distinguish the contribution from different mechanisms to familiarity recognition Hippocampus (IF 3.5) Pub Date : 2023-11-20 John Read, Emma Delhaye, Jacques Sougné
Familiarity is the strange feeling of knowing that something has already been seen in our past. Over the past decades, several attempts have been made to model familiarity using artificial neural networks. Recently, two learning algorithms successfully reproduced the functioning of the perirhinal cortex, a key structure involved during familiarity: Hebbian and anti-Hebbian learning. However, performance
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Hippocampal TMEM55B overexpression in the 5XFAD mouse model of Alzheimer's disease Hippocampus (IF 3.5) Pub Date : 2023-11-14 Kristian F. Odfalk, Jessica L. Wickline, Sabrina Smith, Radek Dobrowolski, Sarah C. Hopp
Dysfunction of the endosomal-lysosomal network is a notable feature of Alzheimer's disease (AD) pathology. Dysfunctional endo-lysosomal vacuoles accumulate in dystrophic neurites surrounding amyloid β (Aβ) plaques and may be involved in the pathogenesis and progression of Aβ aggregates. Trafficking and thus maturation of these dysfunctional vacuoles is disrupted in the vicinity of Aβ plaques. Transmembrane
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Granule cells perform frequency-dependent pattern separation in a computational model of the dentate gyrus Hippocampus (IF 3.5) Pub Date : 2023-11-11 Selena Singh, Suzanna Becker, Thomas Trappenberg, Abraham Nunes
Mnemonic discrimination (MD) may be dependent on oscillatory perforant path input frequencies to the hippocampus in a “U”-shaped fashion, where some studies show that slow and fast input frequencies support MD, while other studies show that intermediate frequencies disrupt MD. We hypothesize that pattern separation (PS) underlies frequency-dependent MD performance. We aim to study, in a computational
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Anticonvulsant effect of equilibrative nucleoside transporters 1 inhibitor in a mouse model of Dravet syndrome Hippocampus (IF 3.5) Pub Date : 2023-11-06 Shih-Yin Ho, I-Chun Chen, Che-Wen Tsai, Kai-Chieh Chang, Chun-Jung Lin, Yijuang Chern, Horng-Huei Liou
There are limited therapeutic options for patients with Dravet syndrome (DS). The equilibrative nucleoside transporters 1 (ENT1) mediate both the influx and efflux of adenosine across the cell membrane exerted beneficial effects in the treatment of epilepsy. This study aimed to evaluate the anticonvulsant effect of the ENT1 inhibitor in an animal model of DS (Scn1aE1099X/+ mice). J7 (5 mg/kg) treatment
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Perceived plausibility modulates hippocampal activity in episodic counterfactual thinking Hippocampus (IF 3.5) Pub Date : 2023-10-31 Kaylee Miceli, Ricardo Morales-Torres, Ari Khoudary, Leonard Faul, Natasha Parikh, Felipe De Brigard
Episodic counterfactual thinking (ECT) consists of imagining alternative outcomes to past personal events. Previous research has shown that ECT shares common neural substrates with episodic future thinking (EFT): our ability to imagine possible future events. Both ECT and EFT have been shown to critically depend on the hippocampus, and past research has explored hippocampal engagement as a function
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Age-related differences in hippocampal subfield volumes across the human lifespan: A meta-analysis Hippocampus (IF 3.5) Pub Date : 2023-10-26 Roya Homayouni, Kelsey L. Canada, Samaah Saifullah, Da' Jonae Foster, Charlotte Thill, Naftali Raz, Ana M. Daugherty, Noa Ofen
The human hippocampus (Hc) is critical for memory function across the lifespan. It is comprised of cytoarchitectonically distinct subfields: dentate gyrus (DG), cornu ammonis sectors (CA) 1-4, and subiculum, each of which may be differentially susceptible to neurodevelopmental and neurodegenerative mechanisms. Identifying age-related differences in Hc subfield volumes can provide insights into neural
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A thalamo-parietal cortex circuit is critical for place-action coordination Hippocampus (IF 3.5) Pub Date : 2023-10-09 Christine M. Simmons, Shawn C. Moseley, Jordan D. Ogg, Xinyu Zhou, Madeline Johnson, Wei Wu, Benjamin J. Clark, Aaron A. Wilber
The anterior and lateral thalamus (ALT) contains head direction cells that signal the directional orientation of an individual within the environment. ALT has direct and indirect connections with the parietal cortex (PC), an area hypothesized to play a role in coordinating viewer-dependent and viewer-independent spatial reference frames. This coordination between reference frames would allow an individual
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Molecular mechanisms underpinning deconditioning-update in fear memory Hippocampus (IF 3.5) Pub Date : 2023-10-05 Bruno Popik, Jordana Griebler Luft, Kétlyn Talise Knak Guerra, Lucas de Oliveira Alvares
Traumatic experiences are closely associated with some psychiatric conditions such as post-traumatic stress disorder. Deconditioning-update promotes robust and long-lasting attenuation of aversive memories. The deconditioning protocol consists of applying weak/neutral footshocks during reactivations, so that the original tone-shock association is replaced by an innocuous stimulus that does not produce
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Cover Image, Volume 33, Issue 10 Hippocampus (IF 3.5) Pub Date : 2023-09-29 Indira Mendez-David, Denis Joseph David, Claudine Deloménie, Laurent Tritchler, Jean-Martin Beaulieu, Romain Colle, Emmanuelle Corruble, Alain Michel Gardier, René Hen
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Optoα1AR activation in astrocytes modulates basal hippocampal synaptic excitation and inhibition in a stimulation-specific manner Hippocampus (IF 3.5) Pub Date : 2023-09-28 Connor D. Courtney, Courtney Sobieski, Charu Ramakrishnan, Robbie J. Ingram, Natalia M. Wojnowski, R. Anthony DeFazio, Karl Deisseroth, Catherine A. Christian-Hinman
Astrocytes play active roles at synapses and can monitor, respond, and adapt to local synaptic activity. While there is abundant evidence that astrocytes modulate excitatory transmission in the hippocampus, evidence for astrocytic modulation of hippocampal synaptic inhibition remains more limited. Furthermore, to better investigate roles for astrocytes in modulating synaptic transmission, more tools
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Variational log-Gaussian point-process methods for grid cells Hippocampus (IF 3.5) Pub Date : 2023-09-25 Michael Everett Rule, Prannoy Chaudhuri-Vayalambrone, Marino Krstulovic, Marius Bauza, Julija Krupic, Timothy O'Leary
We present practical solutions to applying Gaussian-process (GP) methods to calculate spatial statistics for grid cells in large environments. GPs are a data efficient approach to inferring neural tuning as a function of time, space, and other variables. We discuss how to design appropriate kernels for grid cells, and show that a variational Bayesian approach to log-Gaussian Poisson models can be calculated
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Extended trajectory of spatial memory errors in typical and atypical development: The role of binding and precision Hippocampus (IF 3.5) Pub Date : 2023-09-14 Maomiao Peng, Annalysa Lovos, Kenneth Bottrill, Katharine Hughes, Miranda Sampsel, Nancy Raitano Lee, Leonard Abbeduto, Angela John Thurman, Jamie Edgin
Spatial reconstruction, a method for evaluating how individuals remember the placement of objects, has traditionally been evaluated through the aggregate estimation of placement errors. However, this approach may obscure the nature of task errors. Specifically, recent data has suggested the importance of examining the precision of responses, as well as absolute performance on item-context bindings
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A computational model to uncover the biophysical underpinnings of neural firing heterogeneity in dissociated hippocampal cultures Hippocampus (IF 3.5) Pub Date : 2023-09-13 Vaibhav Dhyani, Kevin George, Suman Gare, K. V. Venkatesh, Kishalay Mitra, Lopamudra Giri
Calcium (Ca2+) imaging reveals a variety of correlated firing in cultures of dissociated hippocampal neurons, pinpointing the non-synaptic paracrine release of glutamate as a possible mediator for such firing patterns, although the biophysical underpinnings remain unknown. An intriguing possibility is that extracellular glutamate could bind metabotropic receptors linked with inositol trisphosphate
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Route sequence knowledge supports the formation of cognitive maps Hippocampus (IF 3.5) Pub Date : 2023-09-07 Christopher Hilton, Jan Wiener
In this study, we examined the extent to which knowledge about the sequence of places encountered during route learning supports the formation of a metric cognitive map. In a between subjects design, participants learned a route until they could navigate it independently without error whilst also learning information about either the identity of places along the route (Recognition Learning condition)
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The interaction of global small vessel disease burden and Alzheimer's disease pathologies do not change the independent association of amyloid-beta with hippocampal volume: A longitudinal study on mild cognitive impairment subjects Hippocampus (IF 3.5) Pub Date : 2023-08-28 Mengying Yu, Lufei Feng, Xuemiao Zhao, Qun Huang, Nengzhi Xia, Huwei Xia, Caiyun Wen, Meihao Wang, Zili Zhu, Yunjun Yang
The purpose of this study was to investigate whether the co-existence of global small vessel disease (SVD) burdens and Alzheimer's disease (AD) pathologies change hippocampal volume (HV) and cognitive function of mild cognitive impairment (MCI) subjects. We obtained MRI images, cerebrospinal fluid biomarkers (Aβ1-42 and p-tau), and neuropsychological tests of 310 MCI subjects from ADNI. The global
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Role of T2 relaxometry in localization of mesial temporal sclerosis and the degree of hippocampal atrophy in patients with intractable temporal lobe epilepsy: A cross sectional study Hippocampus (IF 3.5) Pub Date : 2023-08-16 Prasenjit Sarkar, Poonam Sherwani, Rahul Dev, Ashutosh Tiwari
Mesial temporal lobe epilepsy is one of the most common causes of refractory epilepsy worldwide. A good percentage of patients do not have detectable hippocampal atrophy on magnetic resonance imaging (MRI). The objective of this study is to evaluate whether T2 relaxometry can identify hippocampal pathology and lateralize the epileptic focus in patients with intractable temporal lobe epilepsy (TLE)
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Acute cycling exercise and hippocampal subfield function and microstructure in healthy older adults Hippocampus (IF 3.5) Pub Date : 2023-08-01 Daniel D. Callow, Yash Kommula, Craig E. L. Stark, J. Carson Smith
Aging is associated with deterioration in dentate gyrus (DG) and CA3, both crucial hippocampal subfields for age susceptible memory processes such as mnemonic discrimination (MD). Meanwhile, a single aerobic exercise session alters DG/CA3 function and neural activity in both rats and younger adults and can elicit short-term microstructural alterations in the hippocampus of older adults. However, our
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Complex visual discrimination is impaired after right, but not left, anterior temporal lobectomy Hippocampus (IF 3.5) Pub Date : 2023-07-22 Jeremy Gardette, Chrystèle Mosca, Cassandra Asien, Céline Borg, Laure Mazzola, Philippe Convers, Guillaume Gal, Sonja Banjac, Monica Baciu, Bastien Durocher, Philippe Kahane, Pascal Hot
The prevailing view in human cognitive neuroscience associates the medial temporal lobes (MTLs) with declarative memory. Compelling experimental evidence has, however, demonstrated that these regions are specialized according to the representations processed, irrespective of the cognitive domain assessed. This account was supported by the study of patients with bilateral medial temporal amnesia, who
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Cover Image, Volume 33, Issue 8 Hippocampus (IF 3.5) Pub Date : 2023-07-12 Michelle L. Kloc, Yuncai Chen, Jennifer M. Daglian, Gregory L. Holmes, Tallie Z. Baram, Jeremy M. Barry
The cover image is based on the Research Article Spatial learning impairments and discoordination of entorhinal-hippocampal circuit coding following prolonged febrile seizures, by Michelle L. Kloc et al., https://doi.org/10.1002/hipo.23541.
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A complex relation between levels of adult hippocampal neurogenesis and expression of the immature neuron marker doublecortin Hippocampus (IF 3.5) Pub Date : 2023-07-08 Indira Mendez-David, Denis Joseph David, Claudine Deloménie, Laurent Tritchler, Jean-Martin Beaulieu, Romain Colle, Emmanuelle Corruble, Alain Michel Gardier, René Hen
We investigated the mechanisms underlying the effects of the antidepressant fluoxetine on behavior and adult hippocampal neurogenesis (AHN). After confirming our earlier report that the signaling molecule β-arrestin-2 (β-Arr2) is required for the antidepressant-like effects of fluoxetine, we found that the effects of fluoxetine on proliferation of neural progenitors and survival of adult-born granule
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Multiple memory systems for efficient temporal order memory Hippocampus (IF 3.5) Pub Date : 2023-06-26 Anna Jafarpour, Jack J. Lin, Robert T. Knight, Elizabeth A. Buffalo
We report distinct contributions of multiple memory systems to the retrieval of the temporal order of events. The neural dynamics related to the retrieval of movie scenes revealed that recalling the temporal order of close events elevates hippocampal theta power, like that observed for recalling close spatial relationships. In contrast, recalling far events increases beta power in the orbitofrontal
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Mnemonic discrimination deficits in multidimensional schizotypy Hippocampus (IF 3.5) Pub Date : 2023-06-22 Lili Sahakyan, Christopher N. Wahlheim, Thomas R. Kwapil
Current developmental psychopathology models indicate that schizophrenia can be understood as the most extreme expression of a multidimensional continuum of symptoms and impairment referred to as schizotypy. In nondisordered adults, schizotypy predicts risk for developing schizophrenia-spectrum psychopathology. Schizophrenia is associated with disruptions in detecting subtle differences between objects
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Structural plasticity in the entorhinal and perirhinal cortices following hippocampal lesions in rhesus monkeys Hippocampus (IF 3.5) Pub Date : 2023-06-19 Justine Villard, Loïc J. Chareyron, Olivia Piguet, Pauline Lambercy, Gianni Lonchampt, Pamela Banta Lavenex, David G. Amaral, Pierre Lavenex
Immature neurons expressing the Bcl2 protein are present in various regions of the mammalian brain, including the amygdala and the entorhinal and perirhinal cortices. Their functional role is unknown but we have previously shown that neonatal and adult hippocampal lesions increase their differentiation in the monkey amygdala. Here, we assessed whether hippocampal lesions similarly affect immature neurons
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Transcriptional development of the hippocampus and the dorsal–intermediate–ventral axis in rats Hippocampus (IF 3.5) Pub Date : 2023-06-06 Lene C. Olsen, Meital Galler, Menno P. Witter, Pål Sætrom, Kally C. O'Reilly
Risk and resilience for neuropsychiatric illnesses are established during brain development, and transcriptional markers of risk may be identifiable in early development. The dorsal–ventral axis of the hippocampus has behavioral, electrophysiological, anatomical, and transcriptional gradients and abnormal hippocampus development is associated with autism, schizophrenia, epilepsy, and mood disorders
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Long-term depression induction and maintenance across regions of the apical branch of CA1 dendrites Hippocampus (IF 3.5) Pub Date : 2023-05-31 Suhel Parvez, Binu Ramachandran, Medha Kaushik, Heena Tabassum, Julietta U. Frey
Well known as the center for learning and memory, hippocampus is the crucial brain region to study synaptic plasticity in the context of cellular fundamental mechanisms such as long-term depression (LTD) and long-term potentiation (LTP). However, despite years of extensive research, the key to our LTD queries and their induction mechanisms has not been fully understood. Previously, we reported the
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Development and validation of a quality control procedure for automatic segmentation of hippocampal subfields Hippocampus (IF 3.5) Pub Date : 2023-05-28 Kelsey L. Canada, Samaah Saifullah, Jennie C. Gardner, Bradley P. Sutton, Monica Fabiani, Gabriele Gratton, Naftali Raz, Ana M. Daugherty
Automatic segmentation methods for in vivo magnetic resonance imaging are increasing in popularity because of their high efficiency and reproducibility. However, automatic methods can be perfectly reliable and consistently wrong, and the validity of automatic segmentation methods cannot be taken for granted. Quality control (QC) by trained and reliable human raters is necessary to ensure the validity
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Activity-regulated gene expression across cell types of the mouse hippocampus Hippocampus (IF 3.5) Pub Date : 2023-05-24 Erik D. Nelson, Kristen R. Maynard, Kyndall R. Nicholas, Matthew N. Tran, Heena R. Divecha, Leonardo Collado-Torres, Stephanie C. Hicks, Keri Martinowich
Activity-regulated gene (ARG) expression patterns in the hippocampus (HPC) regulate synaptic plasticity, learning, and memory, and are linked to both risk and treatment responses for many neuropsychiatric disorders. The HPC contains discrete classes of neurons with specialized functions, but cell type-specific activity-regulated transcriptional programs are not well characterized. Here, we used single-nucleus
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CA3–CA1 long-term potentiation occurs regardless of respiration and cardiac cycle phases in urethane-anesthetized rats Hippocampus (IF 3.5) Pub Date : 2023-05-23 Miriam S. Nokia, Tomi Waselius, Markku Penttonen
Breathing and heartbeat synchronize to each other and to brain function and affect cognition in humans. However, it is not clear how cardiorespiratory rhythms modulate such basic processes as synaptic plasticity thought to underlie learning. Thus, we studied if respiration and cardiac cycle phases at burst stimulation onset affect hippocampal long-term potentiation (LTP) in the CA3–CA1 synapse in
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The CA2 hippocampal subfield in humans: A review Hippocampus (IF 3.5) Pub Date : 2023-05-19 Ricardo Insausti, Monica Muñoz-López, Ana Maria Insausti
CA2 is probably the most enigmatic of the hippocampal fields. It is small in size (in humans about 500 μm across the mediolateral axis), and yet, it is involved in important functions, such as in social memory and anxiety. This study offers a glimpse of several significant aspects of the anatomical organization of CA2. We present an overview of the anatomical structure of CA2, imbued in the general
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Defining hippocampal area CA2 in the fox (Vulpes vulpes) brain Hippocampus (IF 3.5) Pub Date : 2023-05-09 Serena M. Dudek, Ashley N. Phoenix, Erica Scappini, Darya V. Shepeleva, Yury E. Herbeck, Lyudmila N. Trut, Shannon Farris, Anna V. Kukekova
Since 1959, the Russian Farm-Fox study has bred foxes to be either tame or, more recently, aggressive, and scientists have used them to gain insight into the brain structures associated with these behavioral features. In mice, hippocampal area CA2 has emerged as one of the essential regulators of social aggression, and so to eventually determine whether we could identify differences in CA2 between
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Household socioeconomic status relates to specific hippocampal subfield volumes across development Hippocampus (IF 3.5) Pub Date : 2023-05-03 Kelsey L. Canada, Roya Homayouni, Qijing Yu, Da' Jonae Foster, Sruthi Ramesh, Sarah Raz, Ana M. Daugherty, Noa Ofen
The hippocampus is composed of cytoarchitecturally distinct subfields that support specific memory functions. Variations in total hippocampal volume across development have been linked to socioeconomic status (SES), a proxy for access to material resources, medical care, and quality education. High childhood household SES is associated with greater cognitive abilities in adulthood. Currently, it is
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Disrupted hippocampal synchrony following maternal immune activation in a rat model Hippocampus (IF 3.5) Pub Date : 2023-05-02 Robert G. K. Munn, Amy Wolff, Lucinda J. Speers, David K. Bilkey
Maternal immune activation (MIA) is a risk factor for schizophrenia and other neurodevelopmental disorders. MIA in rats models a number of the brain and behavioral changes that are observed in schizophrenia, including impaired memory. Recent studies in the MIA model have shown that the firing of the hippocampal place cells that are involved in memory processes appear relatively normal, but with abnormalities
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Cover Image, Volume 33, Issue 5 Hippocampus (IF 3.5) Pub Date : 2023-04-24 Edmund T. Rolls, Sylvia Wirth
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Spatial learning impairments and discoordination of entorhinal-hippocampal circuit coding following prolonged febrile seizures Hippocampus (IF 3.5) Pub Date : 2023-04-24 Michelle L. Kloc, Yuncai Chen, Jennifer M. Daglian, Gregory L. Holmes, Tallie Z. Baram, Jeremy M. Barry
How the development and function of neural circuits governing learning and memory are affected by insults in early life remains poorly understood. The goal of this study was to identify putative changes in cortico-hippocampal signaling mechanisms that could lead to learning and memory deficits in a clinically relevant developmental pathophysiological rodent model, Febrile status epilepticus (FSE).
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Single neurons in the human medial temporal lobe flexibly shift representations across spatial and memory tasks Hippocampus (IF 3.5) Pub Date : 2023-04-15 Thomas Donoghue, Runnan Cao, Claire Z. Han, Cameron Monteith Holman, Nicholas J. Brandmeir, Shuo Wang, Joshua Jacobs
Investigations into how individual neurons encode behavioral variables of interest have revealed specific representations in single neurons, such as place and object cells, as well as a wide range of cells with conjunctive encodings or mixed selectivity. However, as most experiments examine neural activity within individual tasks, it is currently unclear if and how neural representations change across
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Hippocampal system neurons encoding views in different species: Introduction to the Special Issue of Hippocampus 2023. Hippocampus (IF 3.5) Pub Date : 2023-04-12 Edmund T Rolls,Sylvia Wirth
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Using multi-task experiments to test principles of hippocampal function Hippocampus (IF 3.5) Pub Date : 2023-04-12 Claire Z. Han, Thomas Donoghue, Runnan Cao, Lukas Kunz, Shuo Wang, Joshua Jacobs
Investigations of hippocampal functions have revealed a dizzying array of findings, from lesion-based behavioral deficits, to a diverse range of characterized neural activations, to computational models of putative functionality. Across these findings, there remains an ongoing debate about the core function of the hippocampus and the generality of its representation. Researchers have debated whether
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Computational cross-species views of the hippocampal formation Hippocampus (IF 3.5) Pub Date : 2023-04-11 Seren L. Zhu, Kaushik J. Lakshminarasimhan, Dora E. Angelaki
The discovery of place cells and head direction cells in the hippocampal formation of freely foraging rodents has led to an emphasis of its role in encoding allocentric spatial relationships. In contrast, studies in head-fixed primates have additionally found representations of spatial views. We review recent experiments in freely moving monkeys that expand upon these findings and show that postural
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Hippocampal spatial view cells, place cells, and concept cells: View representations Hippocampus (IF 3.5) Pub Date : 2023-04-10 Edmund T. Rolls
A commentary is provided on issues raised in the Special Issue of Hippocampus (2023) on hippocampal system view representations. First, the evidence for hippocampal and parahippocampal spatial view cells in primates including humans shows that the allocentric representations provided by at least some of these cells are very useful for human memory in that where objects and rewards are seen in the world
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Acetylcholine-sensitive control of long-term synaptic potentiation in hippocampal CA3 neurons Hippocampus (IF 3.5) Pub Date : 2023-04-04 Randa Kassab
A Hebbian form of long-term potentiation (LTP) is believed to be the basis of memory storage at CA3 recurrent synapses. Abnormalities in CA3 intrinsic connectivity have been related to memory deficits in a variety of neurological disorders. Despite the promise of computational modeling for illuminating the pathogenic implication of connectivity changes, common Hebbian-based models with preset structural
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A place with a view: A first-person perspective in the hippocampal memory space Hippocampus (IF 3.5) Pub Date : 2023-04-03 Sylvia Wirth
How do rodents' and primates' differences in visual perception impact the way the brain constructs egocentric and allocentric reference frames to represent stimuli in space? Strikingly, there are important similarities in the egocentric spatial reference frames through which cortical regions represent objects with respect to an animal's head or body in rodents and primates. These egocentric representations
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View cells in the hippocampus and prefrontal cortex of macaques during virtual navigation Hippocampus (IF 3.5) Pub Date : 2023-03-31 Benjamin W. Corrigan, Roberto A. Gulli, Guillaume Doucet, Borna Mahmoudian, Mohamad Abbass, Megan Roussy, Rogelio Luna, Adam J. Sachs, Julio C. Martinez-Trujillo
Cells selectively activated by a particular view of an environment have been found in the primate hippocampus (HPC). Whether view cells are present in other brain areas, and how view selectivity interacts with other variables such as object features and place remain unclear. Here, we explore these issues by recording the responses of neurons in the HPC and the lateral prefrontal cortex (LPFC) of rhesus
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Reap while you sleep: Consolidation of memories differs by how they were sown Hippocampus (IF 3.5) Pub Date : 2023-03-27 James W. Antony, Eitan Schechtman
Newly formed memories are spontaneously reactivated during sleep, leading to their strengthening. This reactivation process can be manipulated by reinstating learning-related stimuli during sleep, a technique termed targeted memory reactivation. Numerous studies have found that delivering cues during sleep improves memory for simple associations, in which one cue reactivates one tested memory. However
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Mechanisms of mGluR-dependent plasticity in hippocampal area CA2 Hippocampus (IF 3.5) Pub Date : 2023-03-27 Mahsa Samadi, Claire A. Hales, Daniel J. Lustberg, Shannon Farris, Madeleine R. Ross, Meilan Zhao, John R. Hepler, Nicholas H. Harbin, Emma S. J. Robinson, Paul J. Banks, Zafar I. Bashir, Serena M. Dudek
Pyramidal cells in hippocampal area CA2 have synaptic properties that are distinct from the other CA subregions. Notably, this includes a lack of typical long-term potentiation of stratum radiatum synapses. CA2 neurons express high levels of several known and potential regulators of metabotropic glutamate receptor (mGluR)-dependent signaling including Striatal-Enriched Tyrosine Phosphatase (STEP) and