Thalamic stimulation for chronic pain.

Electrical stimulation of the thalamus was found to be effective for the treatment of chronic intractable pain of various etiologies. Diencephalic recordings revealed spontaneous focal electrical discharge patterns with relatively low activation thresholds. Localization of the optimum thalamic discharge site is used as a guide for the electrode implant to be used for chronic stimulation. The thalamic sites which most frequently displayed the low threshold spontaneous focal discharge activity were the CM-Pf complex and related intralaminar nuclear structures. Generation of diencephalic pain-reverberating circuits was discussed in relation to explaining the pain syndromes herein described. The applied electrical stimulation is thought to electrophysiologically 'jam' the low threshold discharging systems and thereby alleviate pain.