Distinct interacting cortical networks for stimulus-response and repetition-suppression.

Non-invasive studies consider the initial neural stimulus response (SR) and repetition suppression (RS) - the decreased response to repeated sensory stimuli - as engaging the same neurons. That is, RS is a suppression of the SR. We challenge this conjecture using electrocorticographic (ECoG) recordings with high spatial resolution in ten patients listening to task-irrelevant trains of auditory stimuli. SR and RS were indexed by high-frequency activity (HFA) across temporal, parietal, and frontal cortices. HFA SR and HFA RS were temporally and spatially distinct, with HFA RS emerging later than HFA SR and showing only a limited spatial intersection with HFA SR : most HFA SR sites did not demonstrate HFA RS , and HFA RS was found where no HFA SR could be recorded. β activity was enhanced in HFA RS compared to HFA SR cortical sites. θ activity was enhanced in HFA SR compared to HFA RS sites. Furthermore, HFA SR sites propagated information to HFA RS sites via transient θ:β phase-phase coupling. In contrast to predictive coding (PC) accounts our results indicate that HFA SR and HFA RS are functionally linked but have minimal spatial overlap. HFA SR might enable stable and rapid perception of environmental stimuli across extended temporal intervals. In contrast HFA RS might support efficient generation of an internal model based on stimulus history.