Alterations of Contralateral Thalamic Perfusion in Neuropathic Pain

Abstract

Contralateral thalamus, the place of termination of spinothalamic tract, is affected in patients with pain. We employed single photon emission computed tomography (SPECT) to evaluate the thalamic perfusion in patients with spontaneous neuropathic pain. Ten patients with complex regional pain syndrome (CRPS) and eleven radiculopathiy patients were enrolled in this study. Regional cerebral blood flow of thalamus was assessed bilaterally by iodine-123-labelled iodoamphetamine SPECT. To standardize the inter-patient data, we set a contralateral thalamic uptake index (CTUI) for assessing thalamic asymmetry. In one study, we found elevation of CTUI in patients with symptoms of neuropathic pain for less than 12 month, whereas no change was observed in the case of a longer lasting disease. An another study demonstrated decrease of CTUI after pain treatment, even though it was unrelated to the pain intensity prior to treatment. Our SPECT study revealed that neuropathic pain altered thalamic neuronal activity. CTUIs were increased in early stage of the disease but decreased as the disease progressed to the chronic stage. These results suggest that CTUI can be used to improve management of neuropathic pain for proper evaluation of spontaneous pain.

Unimpaired endogenous pain inhibition in the early phase of complex regional pain syndrome

“…Thus, our result of a normal CPMeffect and significantly steeper pain reduction during CPM in CRPS within the first year after disease onset correspond to the enhanced thalamic activity of the contralateral side to the affected hand in early CRPS. In contrast, the thalamic activity was decreased in long-lasting CRPS and also chronic radiculopathy (Fukumoto et al, 1999;Ushida et al, 2010), in line with the reported deficient endogenous pain modulation in longer lasting CRPS.…”

Evidence for Thalamic Involvement in the Thermal Grill Illusion: An fMRI Study

“…For example, in as study by Ushida et al, patients with neuropathic pain-onset within 12 months had a hyperperfusion of the contralateral thalamus. This was not observed in patients with pain of longer duration [73]. It is beyond the scope of this paper to discuss the various symptoms and sensory aberrations of different neuropathic pain-states.…”

Rapid treatment-induced brain changes in pediatric CRPS

“…These brain regions have been implicated with the manifestation of movement-related symptoms (basal ganglia) (Schwartzman and Kerrigan 1990; Birklein et al 2000; Marinus et al 2011; Bank et al 2013), autonomic manifestations (Hypo) (Lebel et al 2008; Barad et al 2014), and sensory changes (MD Thal) (Fukumoto et al 1999; Fukui 2003; Fukui et al 2006; Shiraishi et al 2006; Wu et al 2006; Ushida et al 2010; Walton et al 2010). The Hippo contributes to stress regulation via the hypothalamic-pituitary-adrenal axis (HPA axis) by providing inhibitory feedback (Jacobson and Sapolsky 1991).…”