Article
Neurosciences
Yanbo Lian, Anthony N. Burkitt
Summary: This study demonstrates how theta phase precession in hippocampal place cells can emerge from medial entorhinal cortex (MEC) input, explaining the spatial and temporal properties of these cells. The MEC grid cells predominantly determine the temporal response properties of hippocampal place cells in this study.
Article
Neurosciences
Yanbo Lian, Anthony N. Burkitt
Summary: This study investigates the communication between the entorhinal cortex and the hippocampus, as well as the role of sparse coding in the hippocampus. Through a unified learning model, it was found that the spatial tuning properties of hippocampal place cells and dentate gyrus granule cells can be described and simulated, indicating that sparse coding may be an important organizing principle for the brain's navigational system.
Article
Biology
Mi-Seon Kong, Eun Joo Kim, Sanggeon Park, Larry S. Zweifel, Yeowool Huh, Jeiwon Cho, Jeansok J. Kim
Summary: The study found dynamic interaction between fear signaling cells in the basal amygdala (BA) and spatial coding cells in the dorsal hippocampus (dHPC) as animals traverse safe and danger areas in their environment. Only when dHPC cells synchronized with predator-responsive BA cells did they significantly remap as risk locations escalated.
Article
Neurosciences
Noah L. Pettit, Xintong C. Yuan, Christopher D. Harvey
Summary: The expression of spatial maps in the hippocampus can be modulated by the internal state of an animal, resulting in changes even without changes to the external world.
NATURE NEUROSCIENCE
(2022)
Article
Multidisciplinary Sciences
Jake Ormond, John O'Keefe
Summary: The hippocampus plays a crucial role in supporting flexible navigation by encoding location information in a vector-based model, allowing animals to select optimal paths to reach their goals.
Article
Neurosciences
Sam McKenzie, Roman Huszar, Daniel F. English, Kanghwan Kim, Fletcher Christensen, Euisik Yoon, Gyorgy Buzsaki
Summary: The study focuses on how incorporating synthetic hippocampal signals is constrained by preexisting circuit dynamics through optogenetic stimulation of CA1 neurons in mice. Stimulation induced persistent place field remapping and reflected circuit modification through altered spike transmission. The findings suggest that plasticity in recurrent/lateral inhibition may drive learning by rapidly associating existing states.
Article
Multidisciplinary Sciences
Lu Zhang, Stephanie M. Prince, Abigail L. Paulson, Annabelle C. Singer
Summary: This study investigates the role of nonplace cells in memory-guided navigation when spatial cues provide ambiguous information. It is found that nonplace cells differentiate between ambiguous spatial cues and show altered activity and modulation at task-relevant cues. This discrimination is absent in a mouse model of Alzheimer's disease.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2022)
Article
Biology
Balazs B. Ujfalussy, Gergo Orban
Summary: Efficient planning in complex environments requires the representation of uncertainty. This study found that the hippocampus can represent uncertainty by sampling potential motion trajectories randomly and efficiently, contributing to optimal planning.
Article
Biology
Garrett J. Blair, Changliang Guo, Shiyun Wang, Michael S. Fanselow, Peyman Golshani, Daniel Aharoni, Hugh T. Blair
Summary: This study found that place cells in the hippocampus of rats undergo remapping during the memory of aversive events, indicating that reorganization of hippocampal population codes may play a role in storing memories for aversive events.
Article
Neurosciences
Sebi V. Rolotti, Mohsin S. Ahmed, Miklos Szoboszlay, Tristan Geiller, Adrian Negrean, Heike Blockus, Kevin C. Gonzalez, Fraser T. Sparks, Ana Sofia Solis Canales, Anna L. Tuttman, Darcy S. Peterka, Boris V. Zemelman, Franck Polleux, Attila Losonczy
Summary: Hippocampal place cells play a crucial role in spatial navigation and memory, and CA1 pyramidal neurons can rapidly form new place fields within a single trial. However, the rapid recruitment of individual neurons into ensemble representations is likely constrained by local feedback circuits. The interaction between circuit dynamics and rapid feature coding remains unexplored.
Article
Biochemistry & Molecular Biology
Eleonore Duvelle, Roddy M. Grieves, Anyi Liu, Selim Jedidi-Ayoub, Joanna Holeniewska, Adam Harris, Nils Nyberg, Francesco Donnarumma, Julie M. Lefort, Kate J. Jeffery, Christopher Summerfield, Giovanni Pezzulo, Hugo J. Spiers
Summary: The study found that the dorsal CA1 place cells of rats have limited ability to encode environmental connectivity, primarily coding location in a global reference frame with minimal response to doorways and other locations.
Article
Neurosciences
Leila Reddy, Benedikt Zoefel, Jessy K. Possel, Judith Peters, Doris E. Dijksterhuis, Marlene Poncet, Elisabeth C. W. van Straaten, Johannes C. Baayen, Sander Idema, Matthew W. Self
Summary: The study demonstrates the important role of human hippocampal neurons in structuring temporal experiences, showing that these neurons adjust their firing activity according to temporal context to help organize memories of different moments in an experience. Furthermore, human time cells were found to fire at successive moments in structured tasks, as well as signal changing temporal contexts during gap periods.
JOURNAL OF NEUROSCIENCE
(2021)
Review
Cell Biology
Sojeong Pak, Doohyeong Jang, Jinho Lee, Gona Choi, Hongseong Shin, Sungchil Yang, Sunggu Yang
Summary: The hippocampus, particularly its longitudinal connections, plays a crucial role in cognition and behavior. Signal propagation along the longitudinal axis is more enriched than the transverse axis, providing insights into signal convergence and divergence in cognitive functions.
JOURNAL OF CELLULAR PHYSIOLOGY
(2022)
Article
Biochemistry & Molecular Biology
Bruce Harland, Marco Contreras, Madeline Souder, Jean-Marc Fellous
Summary: In a large open environment, most dorsal CA1 place cells exhibit multiple place subfields of different sizes, suggesting a multi-scale representation of space within the dorsal hippocampus.
Article
Biology
Margot Tirole, Marta Huelin Gorriz, Masahiro Takigawa, Lilia Kukovska, Daniel Bendor
Summary: In the dorsal CA1 region of rats, place cells can modulate their firing rate to discriminate between different contexts, independent of place information.
Article
Multidisciplinary Sciences
Caitlin S. Mallory, Kiah Hardcastle, Malcolm G. Campbell, Alexander Attinger, Isabel I. C. Low, Jennifer L. Raymond, Lisa M. Giocomo
Summary: Neural circuits in the medial temporal lobe construct a map-like representation of space that supports navigation by integrating multiple sensory cues and cues related to the individual's movement through the environment. The medial entorhinal cortex (MEC) encodes three-dimensional head movement, eye position, and velocity, alongside other self-motion signals in individual neurons, such as body position, running speed, and azimuthal head direction.
NATURE COMMUNICATIONS
(2021)
Editorial Material
Biochemistry & Molecular Biology
Mark H. Plitt, Lisa M. Giocomo
Summary: The recent study using new holographic optogenetic stimulation technology provides direct evidence that hippocampal place cell activity is sufficient to drive memory and navigation-related behaviors.
Article
Neurosciences
Mark H. Plitt, Lisa M. Giocomo
Summary: The hippocampus contains neural representations capable of supporting declarative memory, with place cells firing in specific locations in different environments. Through large-scale in vivo recordings, it was found that hippocampal remapping across contexts can be precisely predicted by the animal's experience and approximates optimal probabilistic inference. This suggests that place cell remapping allows animals to identify their physical location and estimate the identity of the environment optimally.
NATURE NEUROSCIENCE
(2021)
Review
Neurosciences
Marielena Sosa, Lisa M. Giocomo
Summary: The ability to remember and navigate to spatial locations associated with rewards, such as food or safety, is crucial for survival. The hippocampus and entorhinal cortex play key roles in storing and retrieving reward-related information in the brain by representing physical and mental space as a series of states. This proposal is supported by recent advances in both experimental and theoretical neuroscience, aiming to provide an integrated framework for understanding navigation to reward as a fundamental feature of many cognitive processes.
NATURE REVIEWS NEUROSCIENCE
(2021)
Review
Neurosciences
Jon W. Rueckemann, Marielena Sosa, Lisa M. Giocomo, Elizabeth A. Buffalo
Summary: Researchers propose that hippocampal input drives the grid cell network in both spatial and non-spatial contexts, with interactions between the hippocampus and entorhinal cortex building a topological representation based on temporal ordering of events.
NATURE REVIEWS NEUROSCIENCE
(2021)
Article
Neurosciences
Isabel I. C. Low, Alex H. Williams, Malcolm G. Campbell, Scott W. Linderman, Lisa M. Giocomo
Summary: Neurons in the medial entorhinal cortex exhibit flexibility in neural coding by altering firing properties in response to environmental changes, supporting navigation and memory. Rapid and reversible transitions were observed between multiple spatial maps, synchronized across hundreds of neurons and correlated with changes in running speed. Despite widespread changes in spatial coding, remapping was characterized by a translation along a single dimension in population-level activity space, enabling simple decoding strategies.
Editorial Material
Multidisciplinary Sciences
Isabel I. C. Low, Lisa M. Giocomo
Editorial Material
Neurosciences
Isabel I. C. Low, Lisa M. Giocomo
Summary: Pettit, Yuan, and Harvey discovered that hippocampal spatial maps degrade when mice voluntarily disengage from a navigation task, even without changes in sensory or self-motion cues. This suggests that internal state might play an active role in supporting navigational coding and spatial memory.
NATURE NEUROSCIENCE
(2022)
Editorial Material
Veterinary Sciences
Alexander Gonzalez, Lisa M. Giocomo
Summary: A new study combines a novel behavioral paradigm in rats and humans with reinforcement learning to infer shared computations for goal-directed navigation.
Article
Neurosciences
Ben Sorscher, Gabriel C. Mel, Samuel A. Ocko, Lisa M. Giocomo, Surya Ganguli
Summary: The discovery of entorhinal grid cells has sparked interest in understanding the emergence of hexagonal firing fields in neural circuits and their computational significance. In this study, we demonstrate that hexagonal grids can arise in neural networks trained for path integration under biologically plausible constraints. We also provide a unified theory for the prevalence of hexagonal grids in path-integrator circuits. Our trained networks offer mechanistic hypotheses and capture biological variability better than hand-designed models. Additionally, we develop methods to analyze the connectome and activity maps of our networks, revealing fundamental mechanisms underlying path integration in a generalizable manner.
Article
Biochemistry & Molecular Biology
Linlin Z. Fan, Doo Kyung Kim, Joshua H. Jennings, He Tian, Peter Y. Wang, Charu Ramakrishnan, Sawyer Randles, Yanjun Sun, Elina Thadhani, Yoon Seok Kim, Sean Quirin, Lisa Giocomo, Adam E. Cohen, Karl Deisseroth
Summary: Learning-induced modifications of synaptic and circuit properties storing information in mammals have been unclear. This study used genetically targeted voltage imaging and optogenetic activation to show that specific optogenetic activation of CA1 cells induced stable representations of specific places. It was found that presynaptic CA2/3 cells were required for inducing plasticity in CA1, and during the induction of place fields in single CA1 cells, synaptic input from CA2/3 onto these same cells was potentiated. These findings reveal the synaptic mechanisms underlying hippocampal behavioral timescale plasticity during learning and memory in behaving mammals.
Article
Neurosciences
Emily A. Aery Jones, Lisa M. Giocomo
Summary: The brain represents behaviorally relevant information through the firing of individual neurons and ensembles of neurons. Ensembles in the hippocampus and associated cortical regions support navigation through various types of codes, including single cell codes, population codes, time-compressed sequences, behavioral sequences, and engrams. Traditional definitions of ensembles can constrain or expand potential analyses, and coding can change at the ensemble level while single cell codes remain intact. Broader ensemble definitions are needed to better understand the complexity of the brain.
CURRENT OPINION IN NEUROBIOLOGY
(2023)
Article
Multidisciplinary Sciences
Yanjun Sun, Lisa M. Giocomo
Summary: This study reveals that a subset of neurons in the hippocampus of mice encode drug-associated contextual information, providing insight into how drug abuse alters hippocampal circuitry to encode drug-context associations.
NATURE COMMUNICATIONS
(2022)
Article
Biochemical Research Methods
S. Wenceslao Evans, Dong-Qing Shi, Mariya Chavarha, Mark H. Plitt, Jiannis Taxidis, Blake Madruga, Jiang Lan Fan, Fuu-Jiun Hwang, Siri C. van Keulen, Carl-Mikael Suomivuori, Michelle M. Pang, Sharon Su, Sungmoo Lee, Yukun A. Hao, Guofeng Zhang, Dongyun Jiang, Lagnajeet Pradhan, Richard H. Roth, Yu Liu, Conor C. Dorian, Austin L. Reese, Adrian Negrean, Attila Losonczy, Christopher D. Makinson, Sui Wang, Thomas R. Clandinin, Ron O. Dror, Jun B. Ding, Na Ji, Peyman Golshani, Lisa M. Giocomo, Guo-Qiang Bi, Michael Z. Lin
Summary: By inverting the fluorescence-voltage relationship, the photostability of ASAP family genetically encoded voltage indicators (GEVIs) has been enhanced. Two improved GEVIs, ASAP4b and ASAP4e, enable single-trial detection and recording in standard one- and two-photon microscopes with better temporal resolution. They can simultaneously detect voltage and calcium signals and extend the duration of voltage recordings.
Article
Biology
Isabel I. C. Low, Lisa M. Giocomo, Alex H. Williams
Summary: Researchers found that neurons in navigational brain regions can change their firing patterns in response to changing contextual factors while preserving local computations. By training neural network models to track position and report transiently-cued context changes in simple environments, they showed that the activity patterns are similar to population-wide remapping in the navigational brain region. Furthermore, the models' solution generalizes to more complex navigation and inference tasks.