Article
Biology
Eloy Parra-Barrero, Kamran Diba, Sen Cheng
Summary: The study examines the relationships between theta phase, represented position, and true location in navigation through space in mammalian brains. Existing concepts of 'spatial' or 'temporal' theta sweeps are found to be inadequate in explaining how relevant variables change with running speed. A new concept of 'behavior-dependent' sweeps is introduced, where theta sweep length and place field properties vary based on running speed characteristics at different locations in the environment, providing essential structured heterogeneity for understanding the hippocampal code.
Article
Multidisciplinary Sciences
Davide Spalla, Alessandro Treves, Charlotte N. Boccara
Summary: An essential role of the hippocampal region is to integrate information to compute and update representations. Recent research has shown that neurons in the hippocampal region can conjunctively encode self-motion, position, and direction, potentially uncovering a general algorithm for updating spatial representations.
NATURE COMMUNICATIONS
(2022)
Article
Cell Biology
Prannoy Chaudhuri-Vayalambrone, Michael Everett Rule, Marius Bauza, Marino Krstulovic, Pauline Kerekes, Stephen Burton, Timothy O'Leary, Julija Krupic
Summary: Grid cells and place cells in freely foraging rats were co-recorded, revealing that grid cells have prospective time shifts proportional to their spatial scale, providing an instantaneous readout of increasing time horizons. Place cells have larger time shifts compared to grid cells and also increase with place field sizes. Time horizons are modulated non-linearly by the animal's trajectories in relation to the local boundaries and locomotion cues. Long and short time horizons occur at different parts of the theta cycle, possibly facilitating their readout. These findings suggest that grid and place cell population activity represents local trajectories essential for goal-directed navigation and planning.
Article
Computer Science, Artificial Intelligence
Tristan Baumann, Hanspeter A. Mallot
Summary: The firing fields of hippocampal place cells, known as remapping, change when a rat enters a new compartment in a maze. Remapping cannot be explained solely by path integration and local sensory cues, but requires additional context recognition at gateways between compartments. A model is proposed where place and grid cells follow a joint attractor dynamic, depending on each other's activity and resetting during remapping triggered by passage through a gateway.
Article
Computer Science, Artificial Intelligence
Naigong Yu, Yishen Liao, Hejie Yu, Ouattara Sie
Summary: This study uses a quadruped robot as a platform to solve the robot's position in the environment by obtaining sensory information from its limbs and inertial measurement unit. The position information is then encoded by theta cells and mapped to place cells through a neural network. The experimental results show that the firing effects of spatial cells obtained by the model are consistent with physiological research facts.
CAAI TRANSACTIONS ON INTELLIGENCE TECHNOLOGY
(2022)
Article
Multidisciplinary Sciences
Ziqun Wang, Tao Wang, Fan Yang, Feng Liu, Wei Wang
Summary: This study reports the intrinsic emergence of theta oscillation in a continuous attractor network composed of principal neurons and interneurons. The coexistence of periodic bump attractors and theta rhythm is supported by the structured synaptic connectivity between principal cells and interneurons.
Article
Biology
Tom M. George, William de Cothi, Kimberly L. Stachenfeld, Caswell Barry
Summary: The predictive map hypothesis suggests that each place cell in the hippocampus encodes the expected future occupancy of its target location. Although it is unclear how these successor representations are learned in the brain, a model using spike-timing dependent plasticity (STDP) and theta sweeps shows promise in rapidly learning a close approximation to the successor representation. This biologically plausible model explains various observed phenomena related to successor representations in place cells and provides insight into the topographical ordering of place field sizes.
Article
Multidisciplinary Sciences
Ane Charlotte Christensen, Kristian Kinden Lensjo, Mikkel Elle Lepperod, Svenn-Arne Dragly, Halvard Sutterud, Jan Sigurd Blackstad, Marianne Fyhn, Torkel Hafting
Summary: Perineuronal nets are suggested to stabilize synaptic connections and long-term memories. The removal of perineuronal nets disrupts the temporal and spatial organization of grid cell firing, impacting the stability of representations in both novel and familiar environments. This work indicates that perineuronal nets provide a key stabilizing element for the grid cell network.
NATURE COMMUNICATIONS
(2021)
Article
Multidisciplinary Sciences
Tien-Thong Nguyen Do, Chin-Teng Lin, Klaus Gramann
Summary: Spatial navigation is a complex cognitive process that involves multiple senses and is processed by various brain areas. Previous studies have shown that the retrosplenial complex (RSC) is modulated in a task-related manner during navigation. This study demonstrates evidence of human RSC theta oscillation during active spatial navigation tasks, with pronounced theta power during heading changes, indicating a potential head-direction computation in healthy humans during navigation.
SCIENTIFIC REPORTS
(2021)
Article
Computer Science, Artificial Intelligence
Adithya Krishna, Divyansh Mittal, Siri Garudanagiri Virupaksha, Abhishek Ramdas Nair, Rishikesh Narayanan, Chetan Singh Thakur
Summary: The research has successfully implemented algorithmic and hardware structures mimicking the mammalian spatial navigation system, incorporating grid-cell, place-cell, and decoding modules in a multi-layer architecture to achieve navigation and path integration.
Article
Computer Science, Hardware & Architecture
Yishen Liao, Hejie Yu, Naigong Yu
Summary: This paper proposes a brain-like navigation method inspired by the cognitive mechanism of spatial cells. It constructs neural computational models for path integration, error correction, and navigation path optimization. The experimental results show that the proposed model improves the stability and efficiency of navigation by using visual information and self-organized activity of hippocampal cells.
COMPUTERS & ELECTRICAL ENGINEERING
(2022)
Article
Ecology
Timothy D. Meehan, Sarah P. Saunders, William DeLuca, Nicole L. Michel, Joanna Grand, Jill L. Deppe, Miguel F. Jimenez, Erika J. Knight, Nathaniel E. Seavy, Melanie A. Smith, Lotem Taylor, Chad Witko, Michael E. Akresh, David R. Barber, Erin M. Bayne, James C. Beasley, Jerrold L. Belant, Richard O. Bierregaard, Keith L. Bildstein, Than J. Boves, John N. Brzorad, Steven P. Campbell, Antonio Celis-Murillo, Hilary A. Cooke, Robert Domenech, Laurie Goodrich, Elizabeth A. Gow, Aaron Haines, Michael T. Hallworth, Jason M. Hill, Amanda E. Holland, Scott Jennings, Roland Kays, D. Tommy King, Stuart A. Mackenzie, Peter P. Marra, Rebecca A. McCabe, Kent P. McFarland, Michael J. McGrady, Ron Melcer, D. Ryan Norris, Russell E. Norvell, Olin E. Rhodes, Christopher C. Rimmer, Amy L. Scarpignato, Adam Shreading, Jesse L. Watson, Chad B. Wilsey
Summary: This study presents a three-stage modeling framework for estimating spatial patterns of avian migration by integrating different data sources. The results suggest that incorporating LCP indices with eBird occurrence in the GAMMs can improve the accuracy of predicting observed migratory locations for most species-season models, demonstrating the effectiveness of this comprehensive approach in describing broad-scale spatial patterns of animal movement.
ECOLOGICAL APPLICATIONS
(2022)
Article
Medicine, Research & Experimental
Yue-fan Wang, Sheng-xian Yuan, Hui Jiang, Zhi-xuan Li, Hao-zan Yin, Jian Tan, Zhi-hui Dai, Chun-mei Ge, Shu-han Sun, Fu Yang
Summary: This study investigates the intratumor heterogeneity and immune microenvironment of hepatocellular carcinoma (HCC) using spatial transcriptomics sequencing (ST) techniques. The findings reveal specific spatial expression patterns of immune cells and key molecules in the tumor microenvironment. Key molecules such as CCL15, CCL19, and CCL21 are found to play crucial roles in HCC and are associated with prognosis.
Article
Multidisciplinary Sciences
Lujia Chen, Xiaoxiao Lin, Qiao Ye, Zoran Nenadic, Todd C. Holmes, Douglas A. Nitz, Xiangmin Xu
Summary: Hippocampal CA1 neuronal ensembles generate sequential patterns of firing activity that contribute to episodic memory formation and spatial cognition. We recorded neural ensemble activities in mouse hippocampal CA1 using in vivo calcium imaging and identified sub-populations that are active at the same time. These sub-populations organize as clusters in anatomical space and vary in membership and activity dynamics in different environments. The covariance between dynamics and anatomical location reveals a topographic representation that may guide the generation of hippocampal sequences and organize episodic memory content.
Article
Neurosciences
Farnaz Sharif, Behnam Tayebi, Gyorgy Buzsaki, Sebastien Royer, Antonio Fernandez-Ruiz
Summary: Hippocampal neurons exhibit different spatial coding characteristics in different environments, with superficial place cells more active in cue-poor environments and deep place cells more active in cue-rich environments. These differences are driven by intra-hippocampal and entorhinal inputs, supported by the interaction between excitatory gamma inputs and local inhibition.