title: Changes in brain function and morphology in patients with recurring herpes simplex virus infections and chronic pain.
abstract: A recent study described for the first time a patient group that suffered from spontaneous chronic pain and from recurrent herpes simplex virus (HSV) infections. The patients had pain in widespread areas on one side of the body and were--due to subtle immunological abnormalities--susceptible to HSV infections. Although the clinical features of the pain suggested involvement of the central nervous system, supporting evidence for this was lacking. The objective of this study was to search for changes in the central nervous system that could account for the chronic pain in these patients. We monitored the central processing of pain and touch in eight patients and 11 healthy control subjects, who received painful heat and innocuous tactile stimuli to the hands during functional magnetic resonance imaging. Possible changes in the gray matter density of the brain were assessed with voxel-based morphometry. We found functional changes in the patients' central pain circuitry: activation to heat pain was weaker than in control subjects in the insular cortices, anterior cingulate cortex (ACC), and thalamus, while the activations to innocuous tactile stimuli were similar in both groups. Gray matter density was decreased in the patients' frontal and prefrontal cortices and in the ACC. The observed functional and structural changes in the central pain circuitry, together with the clinical features of the chronic pain support the hypothesis for central involvement in the development of chronic pain in these patients.
authors.affiliation: Brain Research Unit, Low Temperature Laboratory, Helsinki University of Technology, FI-02015 TKK, Espoo, Finland. nuutti@neuro.hut.fi
authors.forename: Nuutti
authors.initials: N
authors.lastname: Vartiainen
authors.forename: Katariina
authors.initials: K
authors.lastname: Kallio-Laine
authors.forename: Yevhen
authors.initials: Y
authors.lastname: Hlushchuk
authors.forename: Erika
authors.initials: E
authors.lastname: Kirveskari
authors.forename: Mikko
authors.initials: M
authors.lastname: Seppänen
authors.forename: Henri
authors.initials: H
authors.lastname: Autti
authors.forename: Veikko
authors.initials: V
authors.lastname: Jousmäki
authors.forename: Nina
authors.initials: N
authors.lastname: Forss
authors.forename: Eija
authors.initials: E
authors.lastname: Kalso
authors.forename: Riitta
authors.initials: R
authors.lastname: Hari
mesh_terms: D000328:Adult; D001921:Brain / Q000098:blood supply / Q000473:pathology* / Q000503:physiopathology*; D001931:Brain Mapping; D002908:Chronic Disease; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006561:Herpes Simplex / Q000150:complications / Q000473:pathology*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D010146:Pain / Q000150:complications / Q000473:pathology*; D010147:Pain Measurement / Q000379:methods; D017288:Pain Threshold / Q000502:physiology; D010812:Physical Stimulation / Q000379:methods; D011601:Psychophysics; D013997:Time Factors; D014110:Touch / Q000502:physiology
chemical_list: D010100:Oxygen