Somatic Sensation and the Insular-Opercular Cortex: Relationship to Central Pain

Abstract

We report 5 stroke patients with lesions affecting the insula and parietal operculum sparing the postcentral gyrus (somatosensory cortical area SI); 3 had spontaneous central poststroke pain (CPSP) and 2 did not. All were imaged and underwent quantitative sensory threshold tests, though not all modalities were tested in all subjects. Tactile thresholds were unaltered in all. The patients with CPSP exhibited greatly elevated thresholds for mechanical pain (skinfold pinch), sharpness and thermal sensations; the pain-free patients had distinctly lesser elevations of their skinfold pinch and innocuous and noxious thermal thresholds, and no sharpness deficit. It is therefore suggested that, in the case of similar cortical lesions, the presence or absence of spontaneous pain either modifies the thresholds for some innocuous modalities, or that the degree of deficit of some innocuous modalities determines whether or not central pain occurs.

Effects of insular stimulation on thermal nociception

“…Thus, the integrity of the posterior insula is necessary for thermal pain processing. Spontaneous pain following a lesion of the insula is associated with a greater loss of thermal pain sensibility (Bowsher, ). Therefore, lighter thermoanalgesia might be more desirable to clinically control chronic pain with posterior insula stimulation.…”

Reduced Regional Gray Matter Volume in Patients with Chronic Obstructive Pulmonary Disease: A Voxel-Based Morphometry Study

“…The finding that patients with insula lesions exhibit a decrease in unpleasant pain, sharpness, and thermal sensation may support our assumption. 28 In addition, mor- phologic reductions in the anterior cingulate cortex could also play a role in the perception of air hunger because it, together with the anterior insula, constitutes a neural substrate for the control and suppression of physiologic urges. 29 The reduced GM in the posterior thalamus may clarify the enhanced breathing movements in patients with COPD.…”

Calcium-stimulated adenylyl cyclase subtype 1 (AC1) contributes to LTP in the insular cortex of adult mice

“…Human imaging studies show that the IC is activated by noxious stimulation and electrical stimulation of the IC induces painful and somatic sensations (Ostrowsky et al, 2002). Moreover, inhibition or lesions in the IC can produces less pain suffering or smaller levels of empathic pain in patients (Greenspan et al, 1999; Bowsher, 2006; Gu et al, 2012). In addition, the acquisition and storage of different learning and memory, such as conditioned taste aversion (CTA), novel taste learning, avoidance and object recognition memory require the involvement of the IC (Berman and Dudai, 2001; Bermudez-Rattoni et al, 2005; Yefet et al, 2006).…”