Review
Biochemistry & Molecular Biology
Angela Kecskes, Boldizsar Czeh, Miklos Kecskes
Summary: This review summarizes the role of mossy cells in healthy and overexcited hippocampus, discussing the controversy surrounding their involvement in temporal lobe epilepsy.
BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH
(2022)
Article
Neurosciences
Cristian Morales, Juan Facundo Morici, Nelson Espinosa, Agostina Sacson, Ariel Lara-Vasquez, M. A. Garcia-Perez, Pedro Bekinschtein, Noelia Weisstaub, Pablo Fuentealba
Summary: Memory systems store and discriminate representations of similar experiences through pattern separation to guide future decisions efficiently. Somatostatin cells in the dentate gyrus play a crucial role in the acquisition of contextual and spatial overlapping memories.
Article
Neurosciences
Selena Singh, Suzanna Becker, Thomas Trappenberg, Abraham Nunes
Summary: This study investigates the mechanisms underlying frequency-dependent mnemonic discrimination in the hippocampal dentate gyrus using a computational model. The findings suggest that both cellular and network-level mechanisms contribute to the performance of mnemonic discrimination, and there is a U-shaped relationship between input frequency and pattern separation.
Article
Neurosciences
Sang-Yoon Kim, Woochang Lim
Summary: We studied the disynaptic effect of hilar cells on pattern separation in a spiking neural network of the hippocampal dentate gyrus. We found that sparsity in the firing activity of granule cells can enhance the efficacy of pattern separation, and the disynaptic effects of mossy cells and HIPP cells are opposite. We also examined the association between sparsely synchronized rhythm and pattern separation in the population and individual firing behaviors.
COGNITIVE NEURODYNAMICS
(2022)
Article
Neurosciences
Carolyn R. Houser, Zechun Peng, Xiaofei Wei, Christine S. Huang, Istvan Mody
Summary: Axonal projections of mossy cells in the dorsal and ventral dentate gyrus show considerable differences, suggesting potential functional divergence between these two regions.
JOURNAL OF NEUROSCIENCE
(2021)
Article
Biochemistry & Molecular Biology
Felipe Fredes, Maria Alejandra Silva, Peter Koppensteiner, Kenta Kobayashi, Maximilian Joesch, Ryuichi Shigemoto
Summary: The study demonstrates the important role of a pathway between ventral mossy cells and dorsal granule cells in the hippocampus in the formation of novelty-induced memory, influencing the activation of dorsal granule cells through excitatory transmission; furthermore, the manipulation of ventral mossy cell activity can bidirectionally regulate the acquisition of novelty-induced contextual memory.
Article
Neurosciences
Fang Zheng, Maria Jesus Valero-Aracama, Natascha Schaefer, Christian Alzheimer
Summary: Activin A enhances hippocampal cell excitability in an enriched environment through non-genomic signaling, possibly by suppressing the GIRK current.
FRONTIERS IN CELLULAR NEUROSCIENCE
(2022)
Article
Neurosciences
Wahab Imam Abdulmajeed, Kai-Yi Wang, Jei-Wei Wu, Musa Iyiola Ajibola, Irene Han-Juo Cheng, Cheng-Chang Lien
Summary: This study reveals the differential regulation of local and distant granule cell activity by mossy cells in the hippocampus, highlighting the distinct synaptic mechanisms involved. These findings provide new insights into the functional organization of hippocampal circuits.
JOURNAL OF PHYSIOLOGY-LONDON
(2022)
Review
Neurosciences
Tasuku Araki, Yuji Ikegaya, Ryuta Koyama
Summary: Hippocampal neurogenesis continues throughout life and is tightly controlled by environmental conditions, with microglia and astrocytes playing key roles in modulating the process. Glial cells release factors that support adult neurogenesis under normal conditions, but can also contribute to inflammation and hinder neurogenesis in diseases like Alzheimer's, depression, and epilepsy.
EUROPEAN JOURNAL OF NEUROSCIENCE
(2021)
Article
Neurosciences
B. Marquez-Valadez, A. Rabano, M. Llorens-Martin
Summary: Alzheimer's disease affects the hippocampus, leading to morphological changes in dentate granule cells (DGCs). Our study reveals that DGCs located in the inner portions of the granule cell layer have shorter and simpler dendrites compared to those in the outer portions. Moreover, AD patients show early morphological alterations in DGCs that worsen as the disease progresses. These findings support the association between hippocampal malfunction and cognitive impairments in AD patients.
ACTA NEUROPATHOLOGICA COMMUNICATIONS
(2022)
Review
Neurosciences
Seong-Beom Park, Heung-Yeol Lim, Eun-Young Lee, Seung-Woo Yoo, Hyun-Suk Jung, Eunsoo Lee, Woong Sun, Inah Lee
Summary: The fasciola cinereum (FC) is a subregion of the hippocampus that shows clear anatomical borders with the CA1 and receives inputs from the lateral entorhinal cortex and perirhinal cortex while projecting exclusively to the crest of the DG. Neurotoxic lesions in the FC impair visual contextual memory acquisition and place recognition in rats, suggesting a critical role in contextual pattern separation in the hippocampus.
PROGRESS IN NEUROBIOLOGY
(2022)
Article
Multidisciplinary Sciences
Paul J. Lamothe-Molina, Andreas Franzelin, Lennart Beck, Dong Li, Lea Auksutat, Tim Fieblinger, Laura Laprell, Joachim Alhbeck, Christine E. Gee, Matthias Kneussel, Andreas K. Engel, Claus C. Hilgetag, Fabio Morellini, Thomas G. Oertner
Summary: Research shows that cFos expression patterns in the mouse dentate gyrus change dramatically from day to day, suggesting that this clock-like selection mechanism may aid in encoding episodic memories.
NATURE COMMUNICATIONS
(2022)
Article
Multidisciplinary Sciences
Katsunori Kobayashi, Kisako Shikano, Mahomi Kuroiwa, Mio Horikawa, Wakana Ito, Akinori Nishi, Eri Segi-Nishida, Hidenori Suzuki
Summary: The activation of D(1)Rs by noradrenaline is crucial for the antidepressant effects, suggesting a potential therapeutic target for depressive disorders. Increased voluntary exercise enhances the synaptic potentiation mediated by D(1)Rs, indicating a distinct role of noradrenaline-D(1)R signaling. This pathway may play a critical role in determining the responsiveness to antidepressant drugs.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2022)
Article
Neurosciences
Lisa N. Miller, Craig Weiss, John F. Disterhoft
Summary: The dentate gyrus plays a crucial role in the formation of associative memories and previous studies have identified populations of cells that bridge the temporal gap during trace eyeblink conditioning. In this study, single-neuron recordings were performed to investigate the functional role of different cell types in the dentate gyrus during learning. The results showed that conditioned mice exhibited changes in firing rate in granule cells, mossy cells, and interneurons, suggesting their involvement in trace associative memory. Theta power also increased during stimuli presentation and decreased over time. These findings expand our understanding of dentate gyrus function and its potential disruptions in aging and disease.
Article
Neurosciences
Carla C. Schmidt, Fang Zheng, Christian Alzheimer
Summary: Activin, a member of the TGF-beta family, has been found to have a neuromodulatory effect on mossy cells (MCs), affecting their excitatory and inhibitory inputs. Increased activin can enhance MC activity, while disruption of activin receptor signaling can reduce MC firing.
Article
Multidisciplinary Sciences
Cheng Wang, Xiaojing Chen, Heekyung Lee, Sachin S. Deshmukh, D. Yoganarasimha, Francesco Savelli, James J. Knierim
Review
Biology
Francesco Savelli, James J. Knierim
JOURNAL OF EXPERIMENTAL BIOLOGY
(2019)
Article
Neurosciences
Heekyung Lee, Douglas GoodSmith, James J. Knierim
CURRENT OPINION IN NEUROBIOLOGY
(2020)
Article
Neurosciences
Heekyung Lee, Zitong Wang, Scott L. Zeger, Michela Gallagher, James J. Knierim
Summary: Research suggests that there is a difference in neural activity along the transverse axis of the CA3 region in aged rats, which may lead to an imbalance between pattern separation and pattern completion, affecting the flexibility of representations.
JOURNAL OF NEUROSCIENCE
(2021)
Article
Biochemistry & Molecular Biology
Douglas GoodSmith, Sang Hoon Kim, Vyash Puliyadi, Guo-li Ming, Hongjun Song, James J. Knierim, Kimberly M. Christian
Summary: The neurons in the dentate gyrus (DG) region of the hippocampus are able to integrate spatial and nonspatial information, forming memories of space and associated stimuli. This study reveals the ability of DG cells to detect changes in the environment and maintain a stable spatial representation.
Article
Biochemistry & Molecular Biology
Heekyung Lee, Zitong Wang, Arjuna Tillekeratne, Nick Lukish, Vyash Puliyadi, Scott Zeger, Michela Gallagher, James J. Knierim
Summary: Age-related deficits in pattern separation bias hippocampal memory processing towards pattern completion. The CA3 region of the hippocampus demonstrates a functional gradient along the transverse axis, with pattern-separated outputs dominant in the proximal CA3 and pattern-completed outputs dominant in the distal CA3.
Article
Neurosciences
Cheng Wang, Heekyung Lee, Geeta Rao, Yoganarasimha Doreswamy, Francesco Savelli, James J. Knierim
Summary: The entorhinal cortex is crucial for episodic memory and spatial navigation. It consists of the medial and lateral subregions, which are responsible for spatial and non-spatial inputs respectively. In this study, the deep-layer entorhinal cortex (LEC) neurons were compared to the superficial-layer LEC neurons in terms of their coding properties. Contrary to the hypothesis, deep-layer LEC neurons showed only slightly more allocentric spatial information than superficial-layer LEC neurons, indicating a transformation of hippocampal spatial outputs to egocentric coding in the deep-layer LEC.
Review
Neurosciences
Mia Borzello, Steve Ramirez, Alessandro Treves, Inah Lee, Helen Scharfman, Craig Stark, James J. Knierim, Lara M. Rangel
Summary: This article compares various theories on the function of the dentate gyrus (DG) in learning and memory, and suggests three critical questions to foster dialogue between these theories. It evaluates previous studies, highlights areas of conflict, and proposes future experiments to bridge the gap between these theories.
NATURE REVIEWS NEUROSCIENCE
(2023)
Article
Cell Biology
Sang Hoon Kim, Douglas GoodSmith, Stephanie J. Temme, Fumika Moriya, Guo-li Ming, Kimberly M. Christian, Hongjun Song, James J. Knierim
Summary: Hippocampal place cells in the dentate gyrus (DG) exhibit spatially modulated firing, and previous studies have drawn different conclusions about their remapping and role in encoding context specificity. By recording granule cells and mossy cells, two populations of place cells in the DG, as mice foraged in different environments, we found that both cell types remapped robustly but through different mechanisms, contributing to orthogonal representations of distinct spatial contexts.