Medial entorhinal cortex activates in a traveling wave in the rat
Abstract
Traveling waves are hypothesized to support the long-range coordination of anatomically distributed circuits. Whether separate strongly-interacting circuits exhibit traveling waves remains unknown. The hippocampus exhibits traveling 'theta' waves and interacts strongly with the medial entorhinal cortex (MEC). To determine whether the MEC also activates in a traveling wave, we performed extracellular recordings of LFP and multi-unit activity along the MEC. These recordings revealed progressive phase shifts in activity, indicating that the MEC also activates in a traveling wave. Variation in theta waveform along the region, generated by gradients in local physiology, contributed to the observed phase shifts. Removing waveform-related phase shifts left significant residual phase shifts. The residual phase shifts covaried with theta frequency in a manner consistent with those generated by weakly coupled oscillators. These results show that coordination of anatomically distributed circuits could be enabled by traveling waves but reveal heterogeneity in the mechanisms generating those waves.
Data availability
Data files have bee be uploaded to crcns.org http://dx.doi.org/10.6080/K0C53J2R
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Extracellular recordings from across the dorsoventral axis of the medial entorhinal cortex of the ratCollaborative Research in Computational Neuroscience, http://dx.doi.org/10.6080/K0C53J2R.
Article and author information
Author details
Funding
Whitehall Foundation
- Ehren L Newman
Consejo Nacional de Ciencia y Tecnología (232364)
- Jesus J Hernández-Pérez
Indiana University Bloomington
- Ehren L Newman
The funders provided resources for the study design, data collection, and interpretation.
Ethics
Animal experimentation: This study was performed in strict accordance with the recommendations in the Guide for the Care and Use of Laboratory Animals of the National Institutes of Health. All of the animals were handled according to approved institutional animal care and use committee (IACUC) protocols (#18-026) of Indiana University, Bloomington. The protocol was approved by the Committee on the Ethics of Animal Experiments of Indiana University, Bloomington (Animal Welfare Assurance Number D16-00587). All surgery was performed under isoflurane anesthesia, and every effort was made to minimize suffering.
Copyright
© 2020, Hernández-Pérez et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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