OHBA SEMINAR SERIES
Dr Saskia Haegens (NYU / Columbia / Donders)
Monday, 14 March 2016, 2pm to 3pm
Department of Psychiatry Seminar Room
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Alpha and high broadband activity track task dynamics and predict performance
Here we use intracranial recordings in human subjects, in order to track neuronal dynamics involved in perceptual decision-making. We focus on the alpha rhythm (8-14 Hz), thought to regulate the engagement and disengagement of neuronal populations based on task demands, and on high broadband activity (70-150 Hz), considered a correlate of multi-unit activity. Taking these two signals, we track activity across cortex using electrocorticography recordings in patients with intractable epilepsy (N=18) performing the Multi-Source Interference Task. This task, a Stroop-like paradigm, allows us to address various cognitive aspects involved in perceptual decision-making. We find a negative relationship between alpha power and high broadband activity. Combined, these activation patterns reflect temporal tracking of task-engaged regions, with alpha decrease and high broadband increase locked to specific task aspects. We report different types of responses, distributed over cortex, including sites that only respond to the stimulus presentation or to the decision report, and interestingly, sites that track the time-on-task. Taken together, alpha and high broadband signals allow us to track neuronal population dynamics across cortex on a fine spatial scale, and give insight in mechanisms underlying perceptual decision-making.