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 and HFA were temporally and spatially distinct, with HFA emerging later than HFA and showing only a limited spatial intersection with HFA: most HFA sites did not demonstrate HFA, and HFA was found where no HFA could be recorded. β activity was enhanced in HFA compared to HFA cortical sites. θ activity was enhanced in HFA compared to HFA sites. Furthermore, HFA sites propagated information to HFA sites via transient θ:β phase-phase coupling. In contrast to predictive coding (PC) accounts our results indicate that HFA and HFA are functionally linked but have minimal spatial overlap. HFA might enable stable and rapid perception of environmental stimuli across extended temporal intervals. In contrast HFA might support efficient generation of an internal model based on stimulus history.