Code for imbalance study comprising three tasks:

ImbalanceFullCircles: 2afc contrast discrimination task. Two circular gratings are presented to the left and to the right of the fixation cross. The contrast of the gratings fluctuates around a mean in ten consecutive samples. Participants should judge which grating had larger contrast on average across the ten samples.

ASSR: auditory steady state response task consists of 100 ripple tones (1000Hz carrier tone with 40 amplitude modulation) and 10 flat tones (1000Hz tone without amplitude modulation) at random positions. Participants should respond with button-press when they hear a flat tone. Ripple tones induce 40 Hz auditory steady state response in auditory cortex (right Heschl's gyrus) that is thought to depend on excitation inhibition balance.

Resting state task: 5 Minutes of resting state during which participants are asked to fixate. This task is used to compute long-range temporal correlation as a marker of E/I ratio.