A mesoscopic electrophysiology platform for the monkey to measure brain function and connectivity in the ketamine model of schizophrenia.

Key aspects of brain function can only be understood by recording from the entire brain in parallel, rather than parts of it in sequence. While fMRI has excellent full-brain coverage and spatial resolution, it is far removed from the millisecond time-scale of neural function. To address this methodological need, my lab developed a new recording modality, mesoscopic electrophysiology, that combines the large field of view and millimeter spatial resolution of fMRI with the millisecond spectro-temporal resolution of electrophysiology. Oursystem consists of a 3-dimensional grid of 992 intracranial electrode contacts that tile the volume of one entire brain hemisphere from cerebellum to orbitofrontal cortex, from motor cortex to hippocampus and from cingulum to the temporal plane.

I will showcase the scientific promise of mesoscopic electrophysiology by describing the effects of subanesthetic doses of ketamine on brain function and connectivity. Our results show that this intervention, which is believed to induce a schizophrenia-like state in the monkey, (i) disrupts the flow of auditory information from auditory to frontal cortex; (ii) disrupts long-range functional connections across the entire brain and frequency spectrum; and (iii) abolishes the emergence and recurrence of stable brain-wide states.