The main goal of this study to integrate techniques producing images of the brain (also called neuroimaging techniques) with non-invasive brain stimulation to investigate factors that may be associated with chronic pain in patients with Trigeminal Neuropathic Pain (TNP).
Trigeminal neuropathic pain (TNP) disorders, such as classical trigeminal and post-surgical neuralgia, are debilitating chronic conditions with pain that is either spontaneous or that can be intensely evoked by light touch to the facial skin. Although neuroimaging techniques have provided insights into some brain mechanisms of experimental trigeminal pain in humans (DaSilva et al., 2002; Borsook et al., 2003), it is not well understood how structural and molecular mechanisms are affected during the course of TNP, and how they can be safely modulated for therapeutic and research purposes. Understanding these processes is crucial to determine the structures engaged in the development and persistence of TNP. We will test the hypothesis that chronicity of TNP is sustained by changes at cellular and molecular levels in neural circuits associated with pain perception and modulation, rather than by the initial peripheral etiology, and that this dysfunction can be safely targeted and modulated as a therapeutic approach by transcranial direct current stimulation (tDCS). To achieve this goal we will use a neuroimaging technique, PET, employing a mathematical model that permits the quantification of opioid receptor availability in vivo.
Study Type
INTERVENTIONAL
Allocation
NON_RANDOMIZED
Purpose
TREATMENT
Masking
SINGLE
Enrollment
13
Two 90 minute scans whose maximum radiological dose is 15 mCi \[11 C\] carfentanil, a selective and specific mu-opioid receptor radioligand. The first one provided baseline data, and the second occurred with the sequence of sham tDCS and tDCS as described in each arm description.
In active tDCS, a 2 milli-amp transcranial direct current stimulation is for 20 minutes.
No radiotracer is used; 3 tesla scanner; all participants have MRI prior to PET scans.
University of Michigan
Ann Arbor, Michigan, United States
Change in MOR BPND levels
change from baseline to versus sham or active tDCS
Time frame: place weeks after not more than 6months
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For sham tDCS, current is applied only for 30 seconds, as sensations arising from tDCS treatment occur only at the beginning of application; however the equipment will be on the participant for 20 minutes to match that of the active tDCS application.