Introducing theta-modulated input into a minimal model of the CA3 region of the hippocampus has significant effects on gamma oscillations. In the absence of theta-modulated input, the gamma oscillations are robust across a range of parameters. Introducing theta-modulated input weakens the gamma oscillations to a power more consistent with power spectra acquired from laboratory animals. With these changes, simulations of the hippocampal model are able to reproduce hippocampal power spectra measured in awake mice.
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http://dx.doi.org/10.1016/j.neucom.2006.10.086 | DOI Listing |
eNeuro
March 2023
School for Psychology and Neuroscience and Centre for Cognitive Neuroimaging, University of Glasgow, Glasgow G12 8QQ, United Kingdom.
Rodent studies suggest that spike timing relative to hippocampal theta activity determines whether potentiation or depression of synapses arise. Such changes also depend on spike timing between presynaptic and postsynaptic neurons, known as spike timing-dependent plasticity (STDP). STDP, together with theta phase-dependent learning, has inspired several computational models of learning and memory.
View Article and Find Full Text PDFRev Neurosci
July 2023
Discipline of Physiology, School of Medicine, Trinity College Dublin, University of Dublin, 152-160 Pearse St., Dublin 2, Ireland.
Grid cells, in entorhinal cortex (EC) and related structures, signal animal location relative to hexagonal tilings of 2D space. A number of modeling papers have addressed the question of how grid firing behaviors emerge using (for example) ideas borrowed from dynamical systems (attractors) or from coupled oscillator theory. Here we use a different approach: instead of asking how grid behavior emerges, we take as a given the experimentally observed intracellular potentials of superficial medial EC neurons during grid firing.
View Article and Find Full Text PDFCereb Cortex
May 2020
Department of Biochemistry, Microbiology and Bio-informatics, Laval University, Québec, PQ, Canada.
Disinhibition is a widespread circuit mechanism for information selection and transfer. In the hippocampus, disinhibition of principal cells is provided by the interneuron-specific interneurons that express the vasoactive intestinal polypeptide (VIP-IS) and innervate selectively inhibitory interneurons. By combining optophysiological experiments with computational models, we determined the impact of synaptic inputs onto the network state-dependent recruitment of VIP-IS cells.
View Article and Find Full Text PDFElife
February 2020
Institute for Experimental Epileptology and Cognition Research, University of Bonn, Bonn, Germany.
Feedback inhibitory motifs are thought to be important for pattern separation across species. How feedback circuits may implement pattern separation of biologically plausible, temporally structured input in mammals is, however, poorly understood. We have quantitatively determined key properties of feedback inhibition in the mouse dentate gyrus, a region critically involved in pattern separation.
View Article and Find Full Text PDFHippocampus
April 2020
Psychology Department, UCLA, Los Angeles, California.
The hippocampal system contains neural populations that encode an animal's position and velocity as it navigates through space. Here, we show that such populations can embed two codes within their spike trains: a firing rate code ( R) conveyed by within-cell spike intervals, and a co-firing rate code ( ) conveyed by between-cell spike intervals. These two codes behave as conjugates of one another, obeying an analog of the uncertainty principle from physics: information conveyed in R comes at the expense of information in , and vice versa.
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