Event-related potentials, CNV, readiness potential, and movement accompanying potential recorded from posterior thalamus in human subjects. A SEEG study

Intracranial recordings were obtained from three patients with intractable chronic pain who underwent analgesic electrical stimulation of the contrala teral thalamus. Multilead electrode made it possible to record from several thalamic nuclei. The electrode was targeted into the ventroposterolateral (VPL) nucleus of the thalamus. During separate recording sessions, the foll owing tests were performed: somatosensory evoked potentials (SEP) of the me dian or posterior tibial nerve, event-related cognitive potentials (auditor y oddball P3 wave), readiness potential (RP) and contingent negative variat ion (CNV) using auditory warning (S1) and visual imperative (S2) stimuli. T he movement accompanying potential (MAP), which was present In the VPL in a ll but one of the recordings, behaved as a far-field potential. Recordings obtained from the VPL confirmed Its established role as a relay nucleus, pr ocessing somatosensory information to the primary somatosensory cortex. The VPL generated the 'thalamic' SEP, which was the only potential regularly r ecorded in this nucleus. In the recordings from one patient (No. 3), audito ry and visual evoked potentials of the CNV protocol, peaking at approximate ly 300 ms, were obtained from the VPL and appeared to be generated in situ, Neither RP, CNV nor 'oddball' ERPs appeared in the VPL. From the pulvinar, only a visually evoked potential was recorded. Oddball P3, RP, CNV, and mi ddle and long latency auditory and visual potentials (evoked in the CNV par adigm) appeared to be generated 'dorsally' to the VPL, probably in the nucl eus posterolateralis (PL). This structure may therefore be involved in both the processing of afferent information and In cognitive operations. (C) 20 01 Editions scientifiques et medicales Elsevier SAS.