Altered sense of self during seizures in the posteromedial cortex.
Level 4 - case-series / case-control
Single-patient case report with intracranial recording and stimulation
PubMed 34272280 · doi:10.1073/pnas.2100522118
What was done
Intracranial electrophysiological recordings were performed in one patient (S19_137) with confirmed seizures localized to the right dorsal posterior cingulate cortex (posteromedial cortex, likely Brodmann area 31). Investigators applied 50-Hz electrical stimulation to the seizure onset zone and contralateral homologous posteromedial cortex, supplementing findings with cortico-cortical evoked potentials, resting-state electrophysiological connectivity, and individual functional imaging.
What was found
Seizure onset and 50-Hz stimulation of both the seizure zone and contralateral posteromedial cortex reproducibly caused subjective self-dissociation, characterized by distorted awareness of body position and feeling like an external observer to one's own thoughts. The abstract reports no numerical data or quantitative effect sizes.
Why it matters
The findings provide direct causal evidence linking posteromedial cortex activity to the integration of self-referential awareness and mechanisms of self-dissociation.
Limits
The report is based on a single patient (n = 1) with epilepsy, limiting generalizability to wider or neurotypical populations. Observations rely primarily on qualitative, subjective self-reports without quantitative behavioral or psychometric metrics reported in the abstract.