[BIC-announce] Special BIC Lecture today - Peter de Weerd: How 17th century physics enlightens today’s gamma synchronization debate

[Boris Bernhardt, Mr]

Dear all -

Please join us for a special BIC seminar today at 1PM in the DeGrandpre communications centre.

"How 17th century physics enlightens today’s gamma synchronization debate”

Peter De Weerd
Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, NLs;
Maastricht Center of Systems Biology, Faculty of Science and Engineering, Maastricht University, NLs.

Abstract
Gamma oscillations are ubiquitous in the brain, and have been associated with important functions including binding and selective attention. The underlying theories have implicitly assumed that gamma oscillations are stable over time, thus forming the basis for synchronization as a tool for enabling neural communication among selected nodes in the brain1.  Single-trial neurophysiological recordings in monkey V1 however show that gamma oscillations are highly variable in frequency and amplitude2. It has been argued that fast variations in gamma frequency in different brain sites prevent synchronization and thus preclude a contribution of gamma to neural communication3. We argue the opposite: When fast and dynamic variations in gamma frequency difference are observed between two recorded brain sites, this is an indication of synchronization and neural communication. In addition, we suggest that the brief and intermittent periods in which the gamma frequency difference is reduced and stabilized demonstrates the existence of a ‘dynamic frequency matching’ mechanism4 that antagonizes factors producing the frequency differences and variations among different brain sites. This idea is in line with how pendulum clocks interact when subtended from a wooden beam, as observed by Huygens, a Dutch physicist who lived in the 17th century. Remarkably, the mathematical equation that describes these interactions was highly predictive for the specific characteristics of gamma synchronization observed in monkey V15. We have shown how dynamic frequency matching may contribute to early vision operations in V1, and suggest it can increase our understanding of entrainment, selective attention and perceptual learning. If the dynamic frequency matching principle can be extended to other brain areas and frequency ranges, it may prove helpful for improving our understanding of a broad range of cognitive phenomena.

Relevant papers
1.   Fries, P. (2015). Rhythms For Cognition: Communication Through Coherence. Neuron 88, 220-235.
2.   Burns, S.P., Xing, D., and Shapley, R.M. (2011). Is gamma-band activity in the local field potential of V1 cortex a “clock” or filtered noise? J Neurosci 31, 9658–9664.
3.   Ray, S., and Maunsell, J.H.R. (2010). Differences in gamma frequencies across visual cortex restrict their possible use in computation. Neuron 67, 885–896.
4.   Roberts, M.J., Lowet, E., Brunet, N.M., Ter Wal, M., Tiesinga, P., Fries, P., and De Weerd, P. (2013). Robust gamma coherence between macaque V1 and V2 by dynamic frequency matching. Neuron 78, 523–536.
5.   Lowet, E., Roberts, M., Peter, A., Gips, B., and De Weerd, P. (2017). A quantitative theory of gamma synchronization in Macaque V1. eLife 6, e26642.


See you all there,
Aki, Boris, and Bratislav
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