title: Differential brain activity in subjects with painful trigeminal neuropathy and painful temporomandibular disorder.
abstract: Human brain imaging investigations have revealed that acute pain is associated with coactivation of numerous brain regions, including the thalamus, somatosensory, insular, and cingulate cortices. Surprisingly, a similar set of brain structures is not activated in all chronic pain conditions, particularly chronic neuropathic pain, which is associated with almost exclusively decreased thalamic activity. These inconsistencies may reflect technical issues or fundamental differences in the processing of acute compared with chronic pain. The appreciation of any differences is important because better treatment development will depend on understanding the underlying mechanisms of different forms of pain. In this investigation, we used quantitative arterial spin labeling to compare and contrast regional cerebral blood flow (CBF) patterns in individuals with chronic neuropathic orofacial pain (painful trigeminal neuropathy) and chronic nonneuropathic orofacial pain (painful temporomandibular disorder). Neuropathic pain was associated with CBF decreases in a number of regions, including the thalamus and primary somatosensory and cerebellar cortices. In contrast, chronic nonneuropathic pain was associated with significant CBF increases in regions commonly associated with higher-order cognitive and emotional functions, such as the anterior cingulate and dorsolateral prefrontal cortices and the precuneus. Furthermore, in subjects with nonneuropathic pain, blood flow increased in motor-related regions as well as within the spinal trigeminal nucleus.
authors.affiliation: Department of Anatomy and Histology, University of Sydney, Sydney, NSW 2006, Australia Departments of Radiology and Radiotherapy, University Medical Center Utrecht, The Netherlands Jaw Function and Orofacial Pain Research Unit, Faculty of Dentistry, University of Sydney, Westmead Hospital, Westmead, NSW 2006, Australia.
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Youssef
authors.forename: Sylvia M
authors.initials: SM
authors.lastname: Gustin
authors.forename: Paul G
authors.initials: PG
authors.lastname: Nash
authors.forename: Jenna M
authors.initials: JM
authors.lastname: Reeves
authors.forename: Esben T
authors.initials: ET
authors.lastname: Petersen
authors.forename: Chris C
authors.initials: CC
authors.lastname: Peck
authors.forename: Greg M
authors.initials: GM
authors.lastname: Murray
authors.forename: Luke A
authors.initials: LA
authors.lastname: Henderson
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001921:Brain / Q000378:metabolism*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000175:diagnosis / Q000378:metabolism*; D010147:Pain Measurement / Q000379:methods*; D013705:Temporomandibular Joint Disorders / Q000175:diagnosis / Q000378:metabolism*; D020433:Trigeminal Nerve Diseases / Q000175:diagnosis / Q000378:metabolism*; D055815:Young Adult
keywords: Cerebral blood flow; Orofacial pain; Temporomandibular disorder; Thalamus; Trigeminal neuropathy