scholarly journals Modulation of visual cortex by hippocampal signals

2019 ◽  
Author(s):  
Julien Fournier ◽  
Aman B Saleem ◽  
E Mika Diamanti ◽  
Miles J Wells ◽  
Kenneth D Harris ◽  
...  

Neurons in primary visual cortex (V1) are influenced by the animal’s position in the environment and encode positions that correlate with those encoded by hippocampus (CA1). Might V1’s encoding of spatial positions be inherited from hippocampal regions? If so, it should depend on non-visual factors that affect the encoding of position in hippocampus, such as the physical distance traveled and the phase of theta oscillations. We recorded V1 and CA1 neurons while mice ran through a virtual corridor and confirmed these predictions. Spatial representations in V1 and CA1 were correlated even in the absence of visual cues. Moreover, similar to CA1 place cells, the spatial responses of V1 neurons were influenced by the physical distance traveled and the phase of hippocampal theta oscillations. These results reveal a modulation of cortical sensory processing by non-sensory estimates of position that might originate in hippocampal regions.


PLoS Biology ◽  
2021 ◽  
Vol 19 (9) ◽  
pp. e3001393
Author(s):  
Jai Y. Yu ◽  
Loren M. Frank

The receptive field of a neuron describes the regions of a stimulus space where the neuron is consistently active. Sparse spiking outside of the receptive field is often considered to be noise, rather than a reflection of information processing. Whether this characterization is accurate remains unclear. We therefore contrasted the sparse, temporally isolated spiking of hippocampal CA1 place cells to the consistent, temporally adjacent spiking seen within their spatial receptive fields (“place fields”). We found that isolated spikes, which occur during locomotion, are strongly phase coupled to hippocampal theta oscillations and transiently express coherent nonlocal spatial representations. Further, prefrontal cortical activity is coordinated with and can predict the occurrence of future isolated spiking events. Rather than local noise within the hippocampus, sparse, isolated place cell spiking reflects a coordinated cortical–hippocampal process consistent with the generation of nonlocal scenario representations during active navigation.



Science ◽  
2020 ◽  
Vol 370 (6513) ◽  
pp. 247-250 ◽  
Author(s):  
Mengni Wang ◽  
David J. Foster ◽  
Brad E. Pfeiffer

Neural networks display the ability to transform forward-ordered activity patterns into reverse-ordered, retrospective sequences. The mechanisms underlying this transformation remain unknown. We discovered that, during active navigation, rat hippocampal CA1 place cell ensembles are inherently organized to produce independent forward- and reverse-ordered sequences within individual theta oscillations. This finding may provide a circuit-level basis for retrospective evaluation and storage during ongoing behavior. Theta phase procession arose in a minority of place cells, many of which displayed two preferred firing phases in theta oscillations and preferentially participated in reverse replay during subsequent rest. These findings reveal an unexpected aspect of theta-based hippocampal encoding and provide a biological mechanism to support the expression of reverse-ordered sequences.



Neuron ◽  
2016 ◽  
Vol 89 (6) ◽  
pp. 1121-1123 ◽  
Author(s):  
Salman E. Qasim ◽  
Joshua Jacobs


2021 ◽  
Author(s):  
Eloy Parra-Barrero ◽  
Kamran Diba ◽  
Sen Cheng

AbstractNavigation through space involves learning and representing relationships between past, current and future locations. In mammals, this might rely on the hippocampal theta phase code, where in each cycle of the theta oscillation, spatial representations start behind the animal’s location and then sweep forward. However, the exact relationship between phase and represented and true positions remains unclear and even paradoxical. Here, we formalize previous notions as ‘spatial’ or ‘temporal’ sweeps, analyze single-cell and population variables in recordings from rat CA1 place cells, and compare them to model simulations. We show that neither sweep type quantitatively accounts for all relevant variables. Thus we introduce ‘behavior-dependent’ sweeps, which fit our key observation that sweep length, and hence place field properties, such as size and phase precession, vary across the environment depending on the running speed characteristic of each location. This structured heterogeneity is essential for understanding the hippocampal code.



2020 ◽  
Author(s):  
Jai Y. Yu ◽  
Loren M. Frank

AbstractThe receptive field of a neuron describes the regions of a stimulus space where the neuron is consistently active. Sparse spiking outside of the receptive field is often considered to be noise, rather than a reflection of information processing. Whether this characterization is accurate remains unclear. We therefore contrasted the sparse, temporally isolated spiking of hippocampal CA1 place cells to the consistent, temporally adjacent spiking seen within their spatial receptive fields (“place fields”). We found that isolated spikes, which occur during locomotion, are more strongly phase coupled to hippocampal theta oscillations than adjacent spikes and, surprisingly, transiently express coherent representations of non-local spatial representations. Further, prefrontal cortical activity is coordinated with, and can predict the occurrence of future isolated spiking events. Rather than local noise within the hippocampus, sparse, isolated place cell spiking reflects a coordinated cortical-hippocampal process consistent with the generation of non-local scenario representations during active navigation.



2020 ◽  
Author(s):  
Grigori Guitchounts ◽  
William Lotter ◽  
Joel Dapello ◽  
David Cox

AbstractThe mammalian brain’s navigation system is informed in large part by visual signals. While the primary visual cortex (V1) is extensively interconnected with brain areas involved in computing head direction (HD) information, it is unknown to what extent navigation information is available in the population activity of visual cortex. To test whether information about head direction information is available in visual cortex, we recorded neuronal activity in V1 of freely behaving rats. We show that significant information about yaw, roll, and pitch of the head can be linearly decoded from V1 either in the presence or absence of visual cues. Individual V1 neurons were tuned to head direction, with a quarter of the neurons tuned to conjunctions of angles in all three planes. These results demonstrate the presence of a critical navigational signal in a primary cortical sensory area and support predictive coding theories of brain function.



2016 ◽  
Author(s):  
Ovidiu Jurjut ◽  
Petya Georgieva ◽  
Laura Busse ◽  
Steffen Katzner

AbstractA fundamental property of visual cortex is to enhance the representation of those stimuli that are relevant for behavior, but it remains poorly understood how such enhanced representations arise during learning. Using classical conditioning in mice, we show that orientation discrimination is learned in a sequence of distinct behavioral stages, in which animals first rely on stimulus appearance before exploiting its orientation to guide behavior. After confirming that orientation discrimination under classical conditioning requires primary visual cortex (V1), we measured, during learning, response properties of V1 neurons. Learning improved neural discriminability, sharpened orientation tuning and led to higher contrast sensitivity. Remarkably, these learning-related improvements in the V1 representation were fully expressed before successful orientation discrimination was evident in the animals’ behavior. We propose that V1 plays a key role early in discrimination learning to enhance behaviorally relevant sensory information.



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