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Tuning the brain: Understanding non-invasive brain stimulation via electrophysiology and coupled oscillators

Matthew Krause, ³ÉÈËVRÊÓƵ
Tuesday February 24, 12-1pm
Zoom Link:Ìý
In Person: 550 Sherbrooke, Room 189

Abstract:ÌýTranscranial Electrical Stimulation (tES) is the oldest yet least understood form of brain stimulation. The technique itself is simple: weak electrical currents are applied to the head in the hopes of altering brain activity and, in turn, behaviour. Over the last two thousand years(!), various groups have reported that tES causes striking improvements in cognition and disease symptoms. Yet these results are frustratingly difficult to replicate, leaving a fundamental question unanswered: does tES meaningfully alter neural activity at all?

Here, we directly address this question by recording the activity of individual neurons in macaque monkeys receiving tES, allowing us to probe how stimulation affects single cells, neural circuits, and behaviour under translationally-relevant conditions. We find that tES does shape brain activity — but its effects are complex and strongly shaped by the brain's own dynamics. Identical stimulation parameters can produce categorically different effects depending on brain state. I will show how coupled oscillator models capture this phenomenon and argue that this framework will ultimately enable us to design simple tES interventions that selectively enhance or suppress brain oscillations involved in neuropsychiatric disease.