Citation

Roland PE, Bonde LH, Forsberg LE, Harvey MA. Front. Syst. Neurosci. 2017; 11: e14.

Affiliation

Department of Physiology, University of Fribourg Fribourg, Switzerland.

Copyright

(Copyright © 2017, Frontiers Research Foundation)

DOI

10.3389/fnsys.2017.00014

PMID

28377701

PMCID

PMC5360108

Abstract

Brain dynamics are often taken to be temporal dynamics of spiking and membrane potentials in a balanced network. Almost all evidence for a balanced network comes from recordings of cell bodies of few single neurons, neglecting more than 99% of the cortical network. We examined the space-time dynamics of excitation and inhibition simultaneously in dendrites and axons over four visual areas of ferrets exposed to visual scenes with stationary and moving objects. The visual stimuli broke the tight balance between excitation and inhibition such that the network exhibited longer episodes of net excitation subsequently balanced by net inhibition, in contrast to a balanced network. Locally in all four areas the amount of net inhibition matched the amount of net excitation with a delay of 125 ms. The space-time dynamics of excitation-inhibition evolved to reduce the complexity of neuron interactions over the whole network to a flow on a low-(3)-dimensional manifold within 80 ms. In contrast to the pure temporal dynamics, the low dimensional flow evolved to distinguish the simple visual scenes.

Language: en

Keywords

balanced network; cerebral cortex; dynamical systems; inhibition; mechanics of vision; voltage sensitive dye