Ephaptic coupling in white matter fibre bundles modulates axonal transmission delays

0546898 - ÚI 2022 US eng J - Journal Article
Schmidt, Helmut - Hahn, G. - Deco, G. - Knösche, T.R.
Ephaptic coupling in white matter fibre bundles modulates axonal transmission delays.
PLoS Computational Biology. Roč. 17, č. 2 (2021), č. článku e1007858. ISSN 1553-734X. E-ISSN 1553-7358
Keywords : local-field potentials * simple reaction-time * evoked-potentials * synchronous spiking * stimulus-intensity * latency * stimulation * origin * cortex * space
Impact factor: 4.779, year: 2021

Axonal connections are widely regarded as faithful transmitters of neuronal signals with fixed delays. The reasoning behind this is that extra-cellular potentials caused by spikes travelling along axons are too small to have an effect on other axons. Here we devise a computational framework that allows us to study the effect of extracellular potentials generated by spike volleys in axonal fibre bundles on axonal transmission delays. We demonstrate that, although the extracellular potentials generated by single spikes are of the order of microvolts, the collective extracellular potential generated by spike volleys can reach several millivolts. As a consequence, the resulting depolarisation of the axonal membranes increases the velocity of spikes, and therefore reduces axonal delays between brain areas. Driving a neural mass model with such spike volleys, we further demonstrate that only ephaptic coupling can explain the reduction of stimulus latencies with increased stimulus intensities, as observed in many psychological experiments.
Permanent Link: http://hdl.handle.net/11104/0323284