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SUMMARY:Poster Flash Talks Group B: Physiological sources of broadband EEG
  signals and applications to monitoring anesthesia - Niklas Brake (McGill 
 University)
DTSTART:20251203T142000Z
DTEND:20251203T142500Z
UID:TALK241096@talks.cam.ac.uk
DESCRIPTION:Niklas Brake\, Flavie Duc\, Alexander Rokos\, Francis Arseneau
 \, Shiva Shahiri\, Anmar Khadra\, Gilles Plourde\nFor nearly a century\, E
 EG has been parsed through the familiar lexicon of oscillations: alpha\, b
 eta\, delta\, and their kin. Yet the non-rhythmic\, or aperiodic\, backgro
 und of the EEG -- often characterized by broadband\, 1/f-like\, spectral f
 eatures -- is also sensitive to cognitive states and pathology. Compared t
 o EEG oscillations\, however\, the physiological basis of these aperiodic 
 signals remains largely unknown. Using biophysical models\, we found two b
 road classes of mechanisms capable of driving differences in broadband EEG
  features. First\, we found that cortical circuits can synchronize with ap
 eriodic fluctuations that are capable of producing detectable\, low-freque
 ncy\, broadband scalp potentials. Second\, we found that the kinetics of G
 ABA receptors strongly shape EEG spectra across all frequencies. This mode
 l prediction was validated by administrating human subjects with propofol\
 , an anesthetic and GABA-A agonist that slows inhibitory decay. Building o
 n this\, we developed a spectral analysis method that infers GABA receptor
  kinetics from EEG and corrects their broadband filtering effects. Applied
  to propofol data\, the method revealed a robust increase in delta rhythms
  at loss of consciousness\, previously obscured by inhibition-driven filte
 ring. Together\, these findings extend EEG theory beyond oscillations\, li
 nking macroscopic spectral features to receptor-level mechanisms. They off
 er a framework for mechanistic biomarkers of unconsciousness and for inter
 pretable EEG-based monitoring in clinical care.
LOCATION:Seminar Room 1\, Newton Institute
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