Evaluation of Pain Perception after Anterior Capsulotomy: A Case Report

Abstract

The medial prefrontal cortex has been implicated in pain perception by recent anatomical, physiological, and functional imaging data demonstrating that frontal and anterior cingulate cortices receive inputs related to nociception; neurosurgical case reports suggest that lesions involving these areas may specifically reduce the affective or emotional component of chronic intractable pain. We examined this hypothesis more closely by assessing psychophysical ratings of (1) warmth, pain intensity, and unpleasantness evoked by phasic thermal stimuli, (2) tolerance to tonic cold stimuli, and (3) perceived intensity of visual stimuli, both before and after neurosurgical lesions of the fiber tracts connecting the frontal lobes to subcortical structures. A 22-year-old male, with no history of chronic pain, underwent psychophysical testing 3 days before, 5 days after, and 6 months after receiving bilateral lesions of the anterior internal capsule (aIC), performed as treatment for obsessive-compulsive disorder. In each session, the patient rated the intensity and unpleasantness of 5-sec cutaneous heat stimuli (39-47 degrees C); pain tolerance was measured by means of a cold-pressor test (hand immersion in 1 degrees C water). The patient was able to differentially rate the intensities of heat stimuli during both pre- and postsurgical testing sessions (p < 0.001). However, he rated heat stimuli as less intense 5 days after surgery than during presurgical testing (p < 0.001), with significant decreases in both pain intensity (p < 0.005) and unpleasantness (p < 0.05). Likewise, the patient described the cold-water immersion as less painful following surgery, although his tolerance times were substantially shorter than those of the presurgical evaluation. Ratings of visual stimulus intensity did not differ across the pre- and postsurgical testing periods, suggesting that changes in pain perception were not related to attentional or cognitive deficits. Magnetic resonance imaging 5 days following surgery revealed bilateral lesions and edema centered in the aIC, with some edema in the left frontal lobe. Those 6 months later showed substantially smaller lesions involving less than half of the aIC and no edema; pain ratings and cold-water tolerance measured at that time indicated a substantial return toward the patient's presurgical values. These data suggest that blocking subcortical input to the anterior cingulate and frontal cortices reduces both the perceived intensity and the unpleasantness of noxious stimuli; reduced cold tolerance times--in the face of decreased pain perception--may reflect a disinhibition of cortical control on spinal reflexes.(ABSTRACT TRUNCATED AT 400 WORDS)

Modulation of induced gamma band activity in the human EEG by attention and visual information processing

“…Only when the figure was in or close to a horizontal orientation occipital gamma band power was increased. Thus, our experiment is in line with other studies in which Gestalt principles were Ž used to form an object, such as co-linearity Tallon et al, 1995;Tallon-Baudry et al, 1996 . Ž see also this volume , common motion Lutzen-.…”

“…We consider this to be an indicator of the activity of wide spread cell assemblies with members in subcortical Ž . limbic and neocortical structures related to the processing of emotional material as suggested by Ž several authors Damasio, 1998;Davidson, 1995Davidson, , 1998Davidson and Hugdahl, 1995;De Pascalis, 1989;Derryberry and Tucker, 1992;Lang et al, 1998;LeDoux, 1995a;Liotti and Tucker, 1995;Talbot et al, 1995;Tucker, 1984;Tucker and . Dawson, 1984 .…”

Dissociable Neural Responses Related to Pain Intensity, Stimulus Intensity, and Stimulus Awareness within the Anterior Cingulate Cortex: A Parametric Single-Trial Laser Functional Magnetic Resonance Imaging Study

“…ACC neurons coding stimulus intensity have been found previously in the anesthetized rabbit (Sikes and Vogt, 1992). Furthermore, clinical data from patients with anterior cingulotomy (Davis et al, 1994) or deafferented anterior cingulate (Talbot et al, 1995) have also shown a diminished sensory coding ability. The only other region showing a similar SRF in our study was the primary sensory cortex.…”

“…Its pivotal role within the nociceptive system has been established in lesion studies (Foltz and White, 1968;Bouckoms, 1989;Talbot et al, 1995) and in numerous functional neuroimaging studies using positron emission tomography (PET) (Jones et al, 1991;Talbot et al, 1991;Casey et al, 1994;Craig et al, 1996;Rainville et al, 1997;Coghill et al, 1999;Casey, 2000) and functional magnetic resonance imaging (fMRI) (Davis et al, 1997;Porro et al, 1998;Ploghaus et al, 1999;Kwan et al, 2000;Sawamoto et al, 2000). The ACC receives nociceptive inputs via medial thalamic nuclei and has been shown to code affective components of painful stimuli (Craig et al, 1996;Rainville et al, 1997;Sawamoto et al, 2000).…”

A PET activation study of dynamic mechanical allodynia in patients with mononeuropathy

“…Peyron et al (1998) suggested that the absence of ACC activation could be a speci®c feature for patients with allodynia after Wallenberg infarct, which may also be the case for allodynia after peripheral nerve damage. The lack of activation in the medial pain system, in contrast to the massive activations in the lateral pain system (7±9% rCBF increase in S1), was still an unexpected ®nding since the patient descriptions of dynamic mechanical allodynia usually include affective components (Hansson, 1994) and since the medial system is considered to be involved in processing the affective and evaluative part of the pain experience (Albe-Fessard et al, 1985;Vogt et al, 1993;Craig et al, 1994;Talbot et al, 1995;Willis, 1995;Rainville et al, 1997).…”