Properties of neuronal activity in cortex and subcortical nuclei of the human brain during single-word processing.

Neuronal impulse activity (NIA) in different cortical areas, subcortical nuclei of the thalamus and striopallidum was recorded via depth electrodes in human patients as they performed a visual word recognition task. The properties of neuronal responsiveness were compared across regions. During single-word processing approximately 75-80% of the responsive cortical neurons were characterized by poststimulus inhibition of firing rate; an increased firing rate (i.e., excitatory response) was observed in about 20-25% of the responsive cortical neurons. Among the subcortical nuclei, mainly in the thalamus and striopallidum, more than 90% of the responsive neurons were characterized by poststimulus excitation; less than 10% exhibited poststimulus inhibition of firing rate.