title: Trigeminal neuropathic pain alters responses in CNS circuits to mechanical (brush) and thermal (cold and heat) stimuli.
abstract: Functional magnetic resonance imaging was used to study patients with chronic neuropathic pain involving the maxillary region (V2) of the trigeminal nerve in patients with spontaneous pain and evoked pain to brush (allodynia). Patients underwent two functional scans (2-3 months apart) with mechanical and thermal stimuli applied to the affected region of V2 and to the mirror site in the unaffected contralateral V2 region, as well as bilaterally to the mandibular (V3) division. Patients were stimulated with brush, noxious cold, and noxious heat. Significant changes were observed in regions within and outside the primary trigeminal sensory pathway. Stimulation to the affected (neuropathic) side resulted in predominantly frontal region and basal ganglia activation compared with the control side. The differences were consistent with the allodynia to brush and cold. A region of interest-based analysis of the trigeminal sensory pathway revealed patterns of activation that differentiated between the affected and unaffected sides and that were particular to each stimulus. Activation in the spinal trigeminal nucleus was constant in location for all pain stimuli. Activation in other brainstem nuclei also showed differences in the blood oxygenation level-dependent signal for the affected versus the unaffected side. Thus, sensory processing in patients with trigeminal neuropathic pain is associated with distinct activation patterns consistent with sensitization within and outside of the primary sensory pathway.
authors.affiliation: Pain and Analgesia Imaging and Neuroscience Group, Department of Psychiatry, McLean Hospital, Belmont, Massachusetts 02478, USA.
authors.forename: Lino
authors.initials: L
authors.lastname: Becerra
authors.forename: Susie
authors.initials: S
authors.lastname: Morris
authors.forename: Shelly
authors.initials: S
authors.lastname: Bazes
authors.forename: Richard
authors.initials: R
authors.lastname: Gostic
authors.forename: Seth
authors.initials: S
authors.lastname: Sherman
authors.forename: Julie
authors.initials: J
authors.lastname: Gostic
authors.forename: Gautam
authors.initials: G
authors.lastname: Pendse
authors.forename: Eric
authors.initials: E
authors.lastname: Moulton
authors.forename: Steven
authors.initials: S
authors.lastname: Scrivani
authors.forename: David
authors.initials: D
authors.lastname: Keith
authors.forename: Boris
authors.initials: B
authors.lastname: Chizh
authors.forename: David
authors.initials: D
authors.lastname: Borsook
mesh_terms: D000328:Adult; D002490:Central Nervous System / Q000502:physiology*; D003080:Cold Temperature / Q000009:adverse effects; D005260:Female; D006358:Hot Temperature; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D009415:Nerve Net / Q000502:physiology*; D010146:Pain / Q000503:physiopathology; D010147:Pain Measurement / Q000379:methods*; D010812:Physical Stimulation / Q000379:methods; D020433:Trigeminal Nerve Diseases / Q000503:physiopathology*