Researchers from the University of Liège (Belgium), in collaboration with colleagues from Milan (Italy), Surrey (UK) and West Virginia (USA), discovered that controlling neuron reactivity is part of the mechanisms used by our biological clock to maintain cognitive functioning. This finding, published in Nature Communications this week, shows that even the simplest aspects of the brain, the strength with which neurons react to simple stimulations in the present case, are affected but the circadian clock, with moments of lower of higher neuronal reactivity.

Without our biological, or circadian, clock we would be sleeping in multiple episodes spread over the 24h day and our performance would not be stable in each wake bouts. The biological clock sends a signal that counter sleep pressure and maintains relatively stable brain functioning during the day (typically for 16h).

Researchers from the University of Liège (Belgium), in collaboration with colleagues from Milan (Italy), Surrey (UK) and West Virginia (USA), discovered that controlling neuron reactivity is part of the mechanisms used by our biological clock to maintain cognitive functioning. This finding shows that even the simplest aspects of the brain, the strength with which neurons react to simple stimulations in the present case, are affected but the circadian clock, with moments of lower of higher neuronal reactivity.

Beyond the advance in our comprehension of the brain, this discovery is important for neurostimulation and neurorehabilitation techniques used for instance in vegetative state or stroke patients or demented or depressed individuals. Applied at the wrong time of day, the efficacy of these therapeutic techniques could be diminished, or even abolished. The findings could also allow a better understanding of epilepsy which, for certain forms, is characterized by more convulsive episodes at certain times of days.

Article: Circadian regulation of human cortical excitability, Julien Q. M. Ly, Giulia Gaggioni, Sarah L. Chellappa, Soterios Papachilleos, Alexandre Brzozowski, Chloé Borsu, Mario Rosanova, Simone Sarasso, Benita Middleton, André Luxen, Simon N. Archer, Christophe Phillips, Derk-Jan Dijk, Pierre Maquet, Marcello Massimini & Gilles Vandewalle, Nature Communications, doi: 10.1038/NCOMMS11828, published online 24 June 2016.