Representations of pleasant and painful touch in the human orbitofrontal and cingulate cortices

The cortical areas that represent affectively positive and negative aspects of touch were investigated using functional magnetic resonance imaging (fMRI) by comparing activations produced by pleasant touch, painful touch produced by a stylus, and neutral touch, to the left hand. It was found that regions of the orbitofrontal cortex were activated more by pleasant touch and by painful stimuli than by neutral touch and that different areas of the orbitofrontal cortex were activated by the pleasant and painful touches. The orbitofrontal cortex activation was related to the affective aspects of the touch, in that the somatosensory cortex (SI) was less activated by the pleasant and painful stimuli than by the neutral stimuli. This dissociation was highly significant for both the pleasant touch (P < 0.006) and for the painful stimulus (P < 0.02). Further, it was found that a rostral part of the anterior cingulate cortex was activated by the pleasant stimulus and that a more posterior and dorsal part was activated by the painful stimulus. Regions of the somatosensory cortex, including SI and part of SII in the mid-insula, were activated more by the neutral touch than by the pleasant and painful stimuli. Part of the posterior insula was activated only in the pain condition and different parts of the brainstem, including the central grey, were activated in the pain, pleasant and neutral touch conditions. The results provide evidence that different areas of the human orbitofrontal cortex are involved in representing both pleasant touch and pain, and that dissociable parts of the cingulate cortex are involved in representing pleasant touch and pain.     

Neural correlates of rapid reversal learning in a simple model of human social interaction

Humans and other primates spend much of their time engaged in social interactions where a crucial ability is to decode face expressions and act accordingly. This rapid reversal learning has been proposed to be important in the relative evolutionary success of primates. Here we provide the first neuroimaging evidence that the ability to change behaviour based on face expression in a model of social interactions is not reflected in the activity in the fusiform face area, but is specifically correlated with activity in the orbitofrontal and anterior cingulate/paracingulate cortices. These brain regions are particularly involved in reversal learning, such that the activations described occurred specifically at the time of reversal, and were also found when different face expressions other than angry were used to cue reversal. The evidence that the orbitofrontal and anterior cingulate/paracingulate cortices are specifically activated at the time of reversal is important for understanding changes in affect and emotional processing in patients with lesions to these brain regions.     

Chronic Arsenic Poisoning From Burning High-Arsenic-Containing Coal In Guizhou, China

Optimization of a previously disclosed sorbitol dehydrogenase inhibitor (SDI, II) for potency and duration of action was achieved by replacing the metabolically labile N,N-dimethylsulfamoyl group with a variety of heterocycles. Specifically, this effort led to a series of novel, in vitro potent SDIs with longer serum half-lives and acceptable in vivo activity in acutely diabetic rats (e.g., 62, 67, and 69). However, the desired in vivo potency in chronically diabetic rats, ED90 less than or equal to 5 mg/kg/day, was achieved only through further modification of the piperazine linker. Several members of this family, including 86, showed better than the targeted potency with ED90 values of 1-2 mg/kg/day. Compound 86 was further profiled and found to be a selective inhibitor of sorbitol dehydrogenase, with excellent pharmacodynamic/pharmacokinetic properties, demonstrating normalization of sciatic nerve fructose in a chronically diabetic rat model for approximately 17 h, when administered orally at a single dose of 2 mg/kg/day.     

Precise intraoperative location of gastrointestinal bleeding with a hand-held counter. Work in progress

The nuclear medicine bleeding scan is frequently insufficient to locate sites of bleeding precisely, in spite of its great sensitivity. A small, hand-held Geiger-Müller counter, placed directly on exposed intestine in the operating room, enables precise location of the probable bleeding site. In three patients, the technique allowed a minimal amount of intestine to be resected, distinguished between large- and small-intestinal hemorrhage, and eliminated other foci as sites of bleeding.