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
Neurosciences
Lucinda J. Speers, Kirsten R. Cheyne, Elena Cavani, Tara Hayward, Robert Schmidt, David K. Bilkey
Summary: The study found that schizophrenia may lead to a greater variability in the starting phase of precession in animals entering new environments, resulting in a disorganization of the ordered representation of experience.
JOURNAL OF NEUROSCIENCE
(2021)
Article
Multidisciplinary Sciences
Laura Green, David Tingley, John Rinzel, Gyorgy Buzsaki
Summary: This study investigates the role of action in the neuronal organization of the hippocampus through a behavioral experiment of training rats to jump a gap. The results indicate that jumping induces consistent electrophysiological patterns in the hippocampus, while the theta spike phase versus animal position relationship remains unchanged.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2022)
Article
Engineering, Electrical & Electronic
Hiroki Noyama, Yuto Yoshikai, Li Bin, Ryuki Iguchi, Kiyoshi Kotani, Yasuhiko Jimbo
Summary: The brain encodes information through the interaction of macro-scale phenomena and micro-scale phenomena, but the interaction between micro- and macro-scale phenomena affecting episodic memory remains unexplained. A new mathematical framework is proposed to predict the conditions under which theta phase precession occurs by constructing models that reproduce micro- and macro-scale phenomena separately and deriving their phase equations. It was found that phase locking or phase shift between micro-scale phase φmicro and macro-scale phase φMacro can reproduce different storage schemes.
IEEJ TRANSACTIONS ON ELECTRICAL AND ELECTRONIC ENGINEERING
(2023)
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.
Review
Neurosciences
Guillaume Etter, James E. Carmichael, Sylvain Williams
Summary: Oscillations in neural activity, particularly theta rhythms in the hippocampus, play a crucial role in learning and memory. While loss of theta rhythmicity impairs memory, spatial-temporal representations persist in altered hippocampal oscillations. This review aims to investigate the contribution of hippocampal oscillations and single-neuron activity to memory function, and propose hypotheses for how septohippocampal oscillations support memory function without directly contributing to hippocampal sequences.
FRONTIERS IN CELLULAR NEUROSCIENCE
(2023)
Article
Neurosciences
Robert G. K. Munn, Amy Wolff, Lucinda J. Speers, David K. Bilkey
Summary: Maternal immune activation (MIA) increases the risk for schizophrenia and other neurodevelopmental disorders. In rat models, MIA mimics the brain and behavioral changes seen in schizophrenia, including memory impairment. This study re-analyzed previous electrophysiological recordings of the hippocampus in MIA and control rats to investigate temporal dysfunction. The findings suggest abnormal gamma power and coherence, altered phase precession of place cells, and an increase in sharp-wave ripple events in the hippocampus of MIA rats, highlighting circuit-level changes that may contribute to information processing deficits in schizophrenia.
Article
Multidisciplinary Sciences
Babak Shahbaba, Lingge Li, Forest Agostinelli, Mansi Saraf, Keiland W. Cooper, Derenik Haghverdian, Gabriel A. Elias, Pierre Baldi, Norbert J. Fortin
Summary: The hippocampus plays a critical role in the temporal organization of experiences, encoding and predicting the sequential order of nonspatial event sequences.
NATURE COMMUNICATIONS
(2022)
Article
Cell Biology
Piergiorgio Salvan, Alberto Lazari, Diego Vidaurre, Francesca Mandino, Heidi Johansen-Berg, Joanes Grandjean
Summary: Human neuroimaging studies have demonstrated that the brain undergoes dynamic transitions between multiple, frequency-tuned states during cognitive processing. In mice, it has been shown that frequency modulation of the entorhinal cortex activity can induce multiple frequency-dependent dynamic states. These findings provide insight into the basic neuronal mechanisms that may underpin flexibility in brain-wide dynamics.
Article
Neurosciences
Roddy M. Grieves, Selim Jedidi-Ayoub, Karyna Mishchanchuk, Anyi Liu, Sophie Renaudineau, Eleonore Duvelle, Kate J. Jeffery
Summary: The study found that in three-dimensional space, grid cells in rats exhibit different firing patterns compared to two-dimensional space, with more variable and irregularly arranged firing fields. This suggests that the self-organization of grid cells is influenced by the structure and movement affordances of the environment.
NATURE NEUROSCIENCE
(2021)
Article
Neurosciences
Yuk-Hoi Yiu, Jill K. Leutgeb, Christian Leibold
Summary: The study reveals that rate and spike timing codes in the hippocampus are related, and the directionality of place field correlations is also associated. This suggests that encoding of directional information in the hippocampus may involve multiple mechanisms, contributing to a better understanding of how directional information is encoded.
JOURNAL OF NEUROSCIENCE
(2022)
Article
Cell Biology
Magdalene Isabell Schlesiger, Tobias Ruff, Duncan Archibald Allan MacLaren, Isabel Barriuso-Ortega, Khalid Magomedovich Saidov, Ting-Yun Yen, Hannah Monyer
Summary: The study reveals that septal PV+ and CB+ projections have differential effects on neuronal activity in the MEC, with PV+ projections disrupting theta-rhythmic firing and CB+ projections increasing burst firing of grid cells. Inactivation of PV+ or CB+ neurons affects context, reference, and working memory to varying degrees.
Article
Clinical Neurology
Lucinda J. Speers, Daena J. Sissons, Lana Cleland, David K. Bilkey
Summary: This study investigated the effects of acute subanesthetic dose of ketamine on phase precession in the CA1 of rats. The results showed that ketamine did not affect the ability of CA1 place cells to precess, but it reduced the range of phase precession. This reduced range could have implications for learning and memory.
JOURNAL OF PSYCHOPHARMACOLOGY
(2023)
Article
Chemistry, Physical
Amit Kumar Pandey, Tarun Kumar Gupta, Abhinav Gupta, Digvijay Pandey
Summary: This paper introduces a novel circuit to improve the performance of large fan-in footless domino by utilizing a new silicon-based network controller to manipulate a weak keeper. The circuit's speed adjusts according to input signals during the evaluation phase and enhances the circuit's robustness when necessary.
Article
Biochemical Research Methods
Lukas Ramlow, Benjamin Lindner
Summary: The author discusses the interval correlations between neural action potentials and studies the interactions between correlated fluctuations, adaptation, and intrinsic dynamics. The research shows that interval correlations in neurons can improve information transmission and signal detection, and proposes a simplified formula applicable to multiple models to explain this correlation.
PLOS COMPUTATIONAL BIOLOGY
(2021)