Immediate to longer-term neurophysiological impact of acute neural network disruption.

Despite substantial interest in how neural systems recover over time after acute neurological events, there is a dearth of longitudinal assessment from minutes to months surrounding these events. We compared rare intraoperative recordings in three patients, obtained immediately before and after anterior temporal lobe resection during a semantic prediction task, with longitudinal source-localized electroencephalography (EEG) obtained 2-6 weeks before, and 2 and 6-14 months after surgery. Relative to controls ( n = 20 ), task performance showed sustained impairment in the two left-hemisphere patients and delayed impact in the right-hemisphere patient. Consistent with theories on ipsilateral and contralateral hemisphere compensation, all patients exhibited bilateral EEG alterations in speech responses and effective connectivity that did not fully recover to pre-operative levels. Direct dataset comparisons of intrinsic neurophysiological biomarkers associated with timescales of processing ( τ INT ) and excitatory-inhibitory balance (aperiodic slope, χ SPEC ) showed a striking months-long reduction in rapid neural timescales of processing and gradually increasing aperiodic slope (putatively reflecting increased cortical inhibition or reduced excitation) specifically in the ipsilateral hemisphere of all three patients. Amidst these neurophysiological alterations, semantic task performance did not return to pre-operative levels. These rare longitudinal data advance a mechanistic framework to non-invasively evaluate neurophysiological impact over multiple timeframes in other patient cohorts.