HUMAN CORTICO-HIPPOCAMPAL ACTIVITY RELATED TO AUDITORY-DISCRIMINATIONREVEALED BY NEUROMAGNETIC FIELD

WE carried out multi-dipole estimation and pursued spatio-temporal bra in activity on a time scale of several milliseconds during an auditory discrimination task using a whole-cortex type SQUID system. Neuronal activities were estimated in the medial (hippocampus, parahippocampal gyrus, etc.) and lateral temporal cortices (superior and middle tempor al gyri, etc.), the dorsolateral prefrontal cortex (middle and inferio r frontal gyri, etc.) and the parietal cortex (supramarginal gyrus, et c.) in the 280-400 ms latency range. The activity in the posterior hip pocampal region was the most prominent and long-lasting in parallel wi th the activities in the other regions. Therefore, the posterior hippo campal region is a central structure engaged in auditory discriminatio n. The whole-cortex neuromagnetic measurements provided the possibilit y of imaging the time-varying activities of the human cortico-hippocam pal neural networks.