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.