Time-resolved large-scale neural coactivations in macaque monkey.

Large-scale distributed activations in various modes of spatiotemporal organizations have been extensively reported in both hemodynamic and electrical/magnetic human brain signals, which provides knowledge on how information is being hierarchically processed and integrated among functionally linked brain regions. These large-scale distributed activations have also been identified in brain signals from animals, indicating that they are preserved brain organizations in species evolution. Recent studies using human electroencephalography (EEG) and magnetoencephalography (MEG) have further revealed that large-scale distributed activations are frequency-specific and of fast dynamics (tens of milliseconds), while these phenomena have not been investigated in animals. The present study used electrocorticography (ECoG) data recorded with the coverage of nearly entire hemisphere(s) to investigate the existence of time-resolved large-scale coactivation patterns (CAPs) in monkey brains and compare them to CAPs from whole-head human EEG data both at resting states. The present results reveal brain-wide patterns of CAPs in monkey ECoG data, which share significant similarities to human EEG CAPs, both in the alpha band, on spatial and temporal patterns not only in individual CAPs but also on relative differences among different CAPs. The transition patterns among all monkey ECoG CAPs further reveal a similar superstructure as in human EEG CAPs that controls the dynamics of brain state transitions at rest and their spatial expressions. These findings suggest that large-scale brain events of fast dynamics exist in non-human primates and they are of functional importance cross species, similar as time-averaged ones that have been well reported in literature.