The superficial layers of the medial entorhinal cortex (MEC) are a major input to the hippocampus. The high proportion of spatially modulated cells, including grid cells and border cells, in these layers suggests that MEC inputs are critical for the representation of space in the hippocampus. However, selective manipulations of the MEC do not completely abolish hippocampal spatial firing. To determine whether other hippocampal firing characteristics depend more critically on MEC inputs, we recorded from hippocampal CA1 cells in rats with MEC lesions. Theta phase precession was substantially disrupted, even during periods of stable spatial firing. Our findings indicate that MEC inputs to the hippocampus are required for the temporal organization of hippocampal firing patterns and suggest that cognitive functions that depend on precise neuronal sequences in the hippocampal theta cycle are particularly dependent on the MEC.
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http://dx.doi.org/10.1038/nn.4056 | DOI Listing |
Cogn Neurodyn
December 2025
School of Systems Science, Beijing Normal University, Beijing, 100875 China.
Hippocampus in the mammalian brain supports navigation by building a cognitive map of the environment. However, only a few studies have investigated cognitive maps in large-scale arenas. To reveal the computational mechanisms underlying the formation of cognitive maps in large-scale environments, we propose a neural network model of the entorhinal-hippocampal neural circuit that integrates both spatial and non-spatial information.
View Article and Find Full Text PDFNat Commun
January 2025
Neurobiology Department, School of Biological Sciences, University of California, San Diego, CA, USA.
The hippocampal CA3 subregion is a densely connected recurrent circuit that supports memory by generating and storing sequential neuronal activity patterns that reflect recent experience. While theta phase precession is thought to be critical for generating sequential activity during memory encoding, the circuit mechanisms that support this computation across hippocampal subregions are unknown. By analyzing CA3 network activity in the absence of each of its theta-modulated external excitatory inputs, we show necessary and unique contributions of the dentate gyrus (DG) and the medial entorhinal cortex (MEC) to phase precession.
View Article and Find Full Text PDFMetab Eng Commun
December 2024
Manchester Institute of Biotechnology (MIB), Department of Chemistry, University of Manchester, Manchester, M1 7DN, UK.
Transcription factor-based biosensors are genetic tools that aim to predictability link the presence of a specific input stimuli to a tailored gene expression output. The performance characteristics of a biosensor fundamentally determines its potential applications. However, current methods to engineer and optimise tailored biosensor responses are highly nonintuitive, and struggle to investigate multidimensional sequence/design space efficiently.
View Article and Find Full Text PDFMaedica (Bucur)
September 2024
Assistant Professor, Department of Pathology, AIIMS (All India Institute of Medical Sciences), Bibinagar, Hyderabad 508126, Telangana, India.
Background: Research evidence suggests the role of the vestibular system in cognitive functions like visuospatial memory, objective memory, spatial navigation, etc. Vestibular cortices send projection to the hippocampus and to the medial entorhinal cortex (MEC); the latter houses place cells, grid cells, and head direction cells, which play a major role in the formation of a cognitive map based on inputs from the vestibular apparatus. So, the present study aimed to assess cognitive functions in vestibular disorder patients.
View Article and Find Full Text PDFbioRxiv
August 2024
Department of Neurology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA.
Behavioral timescale synaptic plasticity (BTSP) is a form of synaptic potentiation where the occurrence of a single large plateau potential in CA1 hippocampal neurons leads to the formation of reliable place fields during spatial learning tasks. We asked whether BTSP could also be a plasticity mechanism for generation of non-spatial responses in the hippocampus and what roles the medial and lateral entorhinal cortex (MEC and LEC) play in driving non-spatial BTSP. By performing simultaneous calcium imaging of dorsal CA1 neurons and chemogenetic inhibition of LEC or MEC while mice performed an olfactory working memory task' we discovered BTSP-like events which formed stable odor-specific fields.
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