title: Functional magnetic resonance imaging response to experimental pain in drug-free patients with schizophrenia.
abstract: Clinical evidence suggests that there is decreased pain sensitivity in schizophrenia; however, the neurobiological mechanism of this decrease remains unknown. Using functional magnetic resonance imaging, we examined the blood oxygen level-dependent (BOLD) changes induced by experimental pain-tolerance (endure) hot stimuli vs. non-painful stimuli during an acute psychotic episode in 12 drug-free patients with schizophrenia and in 13 gender- and age-matched healthy controls. The analyses revealed that patients showed a greater BOLD response at S1 compared with controls but a reduced BOLD response in the posterior cingulate cortex (PCC), insula, and brainstem during pain-tolerance stimuli. Pain-tolerance temperature was higher in patients than in healthy controls. BOLD response in the insula positively correlated with unpleasantness and temperature in controls, but this effect was not observed in patients. S1 BOLD response positively correlated with unpleasantness in patients but not in controls. These initial results confirm that unmedicated patients with schizophrenia have a higher pain tolerance than controls, decreased activation in pain affective-cognitive processing regions (insula, PCC, brainstem), and an over-activation of the primary sensory-discriminative pain processing region (S1). These pilot results are the first to explore the mechanism driving altered pain sensitivity in schizophrenia.
authors.affiliation: Laboratorio de Psiquiatría Experimental, Instituto Nacional de Neurología y Neurocirugía, Mexico City, Mexico.
authors.forename: Camilo
authors.initials: C
authors.lastname: de la Fuente-Sandoval
authors.forename: Rafael
authors.initials: R
authors.lastname: Favila
authors.forename: Diana
authors.initials: D
authors.lastname: Gómez-Martin
authors.forename: Francisco
authors.initials: F
authors.lastname: Pellicer
authors.forename: Ariel
authors.initials: A
authors.lastname: Graff-Guerrero
mesh_terms: D000328:Adult; D001921:Brain / Q000098:blood supply* / Q000503:physiopathology; D001931:Brain Mapping; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D005260:Female; D007839:Functional Laterality; D006358:Hot Temperature / Q000009:adverse effects; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging; D008297:Male; D010100:Oxygen / Q000097:blood; D010146:Pain / Q000209:etiology / Q000473:pathology*; D017288:Pain Threshold / Q000502:physiology; D012189:Retrospective Studies; D012559:Schizophrenia / Q000503:physiopathology*; D012565:Schizophrenic Psychology; D055815:Young Adult
chemical_list: D010100:Oxygen