title: Visceral pain evoked by thalamic microstimulation in humans.
abstract: Microstimulation within and below the ventrocaudal nucleus (Vc) in the human thalamus typically evokes non-painful, paraesthetic cutaneous sensations. We now describe cases in which thalamic microstimulation evoked visceral pains. Data were obtained during stereotactic thalamotomy procedures. Patient 211 had a history of essential tremor. At a site 0.5 mm ventroposterior to Vc, microstimulation elicited pain described as 'deep, internal, in a straight line like my appendix pain years ago'. Patient 153 had a history of post-stroke hemibody pain. In each of two trajectories, at sites approximately 2 mm ventroposterior to Vc, microstimulation evoked pain in the groin. At one of these sites, the pain was described as 'like having a baby'. These and additional observations suggest that stimulation ventroposterior to Vc can evoke visceral pain and may trigger pain 'memories'.
authors.affiliation: Division of Neurosurgery, University of Toronto, Ontario, Canada.
authors.forename: K D
authors.initials: KD
authors.lastname: Davis
authors.forename: R R
authors.initials: RR
authors.lastname: Tasker
authors.forename: Z H
authors.initials: ZH
authors.lastname: Kiss
authors.forename: W D
authors.initials: WD
authors.lastname: Hutchison
authors.forename: J O
authors.initials: JO
authors.lastname: Dostrovsky
mesh_terms: D000328:Adult; D004558:Electric Stimulation; D005260:Female; D006801:Humans; D008839:Microelectrodes; D008875:Middle Aged; D010146:Pain / Q000503:physiopathology*; D013787:Thalamic Nuclei / Q000503:physiopathology*; D014781:Viscera / Q000294:innervation*