Passive mapping of hand motor cortex across altered states of consciousness.
The International journal of neuroscience April 26, 2025 Yusheng Tong, Zhen Fan, Xiang Zou et al.
Median nerve stimulation combined with high gamma band activity can map the hand motor cortex during awake states, but its effectiveness declines with loss of consciousness. In five patients undergoing awake craniotomy, the sensitivity of mapping using the short-latency average envelope remained relatively stable, dropping only from 100% awake to about 82% during deeper anesthesia stages. In contrast, mapping based on average power deteriorated more sharply, from 100% awake to around 21% at the deepest stage. The long-latency average envelope also showed reduced sensitivity as consciousness declined, with a slope coefficient significantly smaller than that for short-latency responses. These results suggest that short-latency envelope-based mapping is more robust across different conscious states.