Effect of midbrain stimulus-induced analgesia on immune function in humans

Electrical stimulation of midbrain structures produces significant and clinically useful analgesia in humans. However, it has been suggested to have immunosuppressive effects in animals. We evaluated immune function in two women who were utilizing implanted midbrain electrodes for pain control. An elevated B cell percentage was observed in one patient after a 72-h control rest period and this was followed by a reproducible fall in B cells after acute stimulation. However, midbrain electrical stimulation did not appear to have any other acute or chronic effects on these persons' immune functions.