Single Subject Pharmacological-MRI (phMRI) Study: Modulation of Brain Activity of Psoriatic Arthritis Pain by Cyclooxygenase-2 Inhibitor

Abstract

We use fMRI to examine brain activity for pain elicited by palpating joints in a single patient suffering from psoriatic arthritis. Changes in these responses are documented when the patient ingested a single dose of a selective cyclooxygenase-2 inhibitor (COX-2i). We show that mechanical stimulation of the painful joints exhibited a cortical activity pattern similar to that reported for acute pain, with activity primarily localized to the thalamus, insular, primary and secondary somatosensory cortices and the mid anterior cingulum. COX-2i resulted in significant decreased in reported pain intensity and in brain activity after 1 hour of administration. The anterior insula and SII correlated with pain intensity, however no central activation site for the drug was detected. We demonstrate the similarity of the activation pattern for palpating painful joints to brain activity in normal subjects in response to thermal painful stimuli, by performing a spatial conjunction analysis between these maps, where overlap is observed in the insula, thalamus, secondary somatosensory cortex, and anterior cingulate. The results demonstrate that one can study effects of pharmacological manipulations in a single subject where the brain activity for a clinical condition is delineated and its modulation by COX-2i demonstrated. This approach may have diagnostic and prognostic utility.

Chronic pain: The role of learning and brain plasticity

“…These results, together with our fMRI studies in other chronic pain conditions (Baliki et al, 2008; Baliki et al, 2005; Farmer et al, 2011; Geha et al, 2007; Geha, Baliki, Wang, et al, 2008) and our additional brain morphometry studies (Baliki, Schnitzer, et al, 2011; Geha, Baliki, Harden, et al, 2008), have prompted the proposal of a new mechanistic model for the transition to pain chronicity. This model was proposed and expounded in three review articles (Apkarian, 2008; Apkarian et al, 2009; Apkarian et al, 2011).…”

Neuroimaging as a Tool for Pain Diagnosis and Analgesic Development

“…The evoked pain results in similar brain activation as the acute pain in healthy controls. [43][44][45] Tonic clinical pain results in a different brain activity pattern than evoked clinical pain; for example, dynamic mechanical allodynia in patients with post-herpetic neuralgia results in different activation patterns than the ongoing pain. 43,46 Also the evoked pain differs from the ongoing, tonic pain in patients with arthritis.…”

Spontaneous pain and brain activity in neuropathic pain: Functional MRI and pharmacologic functional MRI studies

“…A patient with chronic psoriatic pain was studied for brain activity regarding joint pain before and after oral administration of a cyclooxygenase-2 (COX-2) inhibitor [34]. The patient refrained from using his COX-2 inhibitor for 24 hours before participating in the study.…”