Perception and suppression of thermally induced pain: A fMRI study

Abstract

Two neuroimaging studies using functional magnetic resonance imaging (fMRI) and thermally induced pain are presented. Fifteen healthy right-handed subjects were imaged while they had to discern different levels of thermal stimuli in the first study and while they disengaged from the feeling of pain during constant stimulation in the second study. In the first experiment, during painful phasic stimuli, right-sided anterior insular activation as well as bilateral posterior insular activation could be shown regardless of stimulation side, as well as right-sided activation of sensory association areas in the superior parietal lobule. Also, activation of the ipsilateral sensorimotor cortex could be shown. In the second experiment, all subjects succeeded in suppressing the feeling of pain during previously painful levels of stimulation. During the early part of the tonic painful stimulation, bilateral activation of caudate head and dorsolateral prefrontal cortex (DLPFC) as well as insular cortex and dorsal anterior cingulated cortex (dACC) was observed. During the late part of the tonic painful stimulation, anterior insular activation as well as dACC and bilateral prefrontal cortical activation could be shown. Taken together, the activation of PFC and caudate nucleus hints at an important role in the initiation (caudate) and maintenance (PFC) of suppression of the feeling of pain. No ipsilateral sensorimotor activation could be shown in the second experiment. The possible import of unwanted sensorimotor activation due to the simultaneous rating process in the first experiment is discussed.

Prefrontal hemodynamic mapping by functional near-infrared spectroscopy in response to thermal stimulations over three body sites

“…44 Another recent fMRI study also reported significant activations in several cortical and subcortical regions when a high-pain cold stimulus was applied to the thenar surface of the right hand. The activated regions included, but were not limited to, the bilateral anterior insula, bilateral dorsal ACC extending into the presupplementary motor area (BAs 6,8,24,32), and the right lateral PFC (i.e., DLPFC and VLPFC; BAs 9,10,44,45,46,47). 45 In this study, our results also present similar activations in several prefrontal cortical areas (such as BAs 8, 9, 10, 6 and 7].…”

“…In addition, they suggested that the caudate nucleus and PFC play a crucial role in initiation and maintenance of suppression of pain, respectively. 46 Another fMRI study by a separate group also demonstrated the role of the anterolateral PFC in expected and perceived control over pain. 17 Also, a PET-based study of pain reported the influence of DLPFC on pain perception by modulating cortico-subcortical and cortico-cortical pathways.…”

“…An fMRI-based pain study by Freund et al 46 reported that the DLPFC and caudate nucleus were significantly activated when healthy subjects made efforts to disengage from feeling pain during constant thermal stimulation. In addition, they suggested that the caudate nucleus and PFC play a crucial role in initiation and maintenance of suppression of pain, respectively.…”

Insula-specific responses induced by dental pain. A proton magnetic resonance spectroscopy study

“…Among these, the insular cortex is described as one of the most consistently activated structures and seems to play a pivotal role within the cortical pain circuitry. Hence, the significance of the insular cortex as a core structure in pain processing has been established [1,9,[11][12][13][14][15][16].…”

Effects of trauma-related cues on pain processing in posttraumatic stress disorder: an fMRI investigation

“…51 Electrical stimulation of the caudate has been shown to provide relief from pain in patients with chronic pain, possibly by inhibiting the activity of the medial thalamus. 52 The specific area in the caudate head identified by the betweengroup contrast (Montreal Neurological Institutes [MNI] coordinates 4, 16, 0) has previously also been implicated in modulation of pain intensity through expectancy 53 and at the onset of effortful suppression of thermally induced pain, 54 indicating that top-down modulation may be at play. However, the brain regions that have previously been implicated in top-down modulation, namely the anterior cingulate cortex and the medial prefrontal cortex, 46,55,56 did not show increased activations.…”