Basal ganglia involvement in sensory and cognitive processing. A depth electrode CNV study in human subjects

Objective: Intracranial recordings were taken from the basal ganglia (BG) in order to explore the possible role of the BG in the cognitive processing of sensory information. Methods: Ten patients with intractable temporal lobe epilepsy, who were candidates for epilepsy surgery, underwent intracranial recordings with depth electrodes. A frontal approach was used for the insertion of diagonal depth electrodes into the amygdalo-hippocampal complex (AH complex). These electrodes passed through the BG. The putamen was explored in 8 patients; the nucleus caudatus and pallidum were explored in two patients. The contingent negative variation (CNV) paradigm was tested using auditory warning stimuli and visual imperative stimuli followed by a hand flexion. The auditory and visual middle and late latency potentials evoked by the warning and imperative stimuli were analyzed. Results: (1) Auditory evoked potentials (EPs): the amplitude potential gradient was observed with latencies of (a) 150–195 ms (9 patients); (b) 215–290 ms (9 patients); and (c) 350–600 ms (10 patients). Negative potentials, with latencies of 100 and 110 ms were observed in two patients. (2) Visual EPs: (a) 160–195 ms (9 patients); (b) 210–295 ms (9 patients); and (c) 330–550 ms (7 patients). Negative potentials with latencies between 100 and 120 ms were observed in 4 patients. CNV was obtained from the BG in 8 patients; a phase reversal was observed twice. Conclusions: (1) The BG generate middle and late latency EPs in a cognitive paradigm linked to the motor task. (2) The BG generate CNV. (3) The BG could play an integrative role in the processing of sensory, cognitive, and motor information.