Multiple Running Speed Signals in Medial Entorhinal Cortex

Grid cells in medial entorhinal cortex (MEC) can be modeled using oscillatory interference or attractor dynamic mechanisms that perform path integration, a computation requiring information about running direction and speed. The two classes of computational models often use either an oscillatory fre...

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Bibliographic Details
Published in:Neuron (Cambridge, Mass.) Mass.), 2016-08, Vol.91 (3), p.666-679
Main Authors: Hinman, James R., Brandon, Mark P., Climer, Jason R., Chapman, G. William, Hasselmo, Michael E.
Format: Article
Language:English
Subjects:
Action Potentials - physiology
Animals
Behavior
entorhinal cortex
Entorhinal Cortex - physiology
Experiments
grid cell
Male
medial septum
Models, Neurological
Neurons
path integration
Physiology
Rats
Rodents
Running - physiology
Septal Nuclei - physiology
theta rhythm
Theta Rhythm - physiology
Walking Speed - physiology
Word processing
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Summary:Grid cells in medial entorhinal cortex (MEC) can be modeled using oscillatory interference or attractor dynamic mechanisms that perform path integration, a computation requiring information about running direction and speed. The two classes of computational models often use either an oscillatory frequency or a firing rate that increases as a function of running speed. Yet it is currently not known whether these are two manifestations of the same speed signal or dissociable signals with potentially different anatomical substrates. We examined coding of running speed in MEC and identified these two speed signals to be independent of each other within individual neurons. The medial septum (MS) is strongly linked to locomotor behavior, and removal of MS input resulted in strengthening of the firing rate speed signal, while decreasing the strength of the oscillatory speed signal. Thus, two speed signals are present in MEC that are differentially affected by disrupted MS input. •Two dissociable running speed signals are present in medial entorhinal cortex (MEC)•Medial septal inactivation strengthens the firing rate speed signal in MEC•Speed modulation of intrinsic theta frequency is decreased during MS inactivation•A sizable percentage of MEC neurons are negatively speed modulated Hinman et al. demonstrate the presence of multiple running speed signals in medial entorhinal cortex that are differentially dependent upon intact medial septal input. Running speed signals are a critical component in models of grid cell generation.
ISSN:0896-6273
1097-4199
DOI:10.1016/j.neuron.2016.06.027