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In two experiments including a total of 30 irritable bowel syndrome patients, symptom-mimicking rectal pressure stimuli elicited changes in regional neural activation as measured by positron electron tomography (PET) cerebral blood flow images. Although most stimuli were not rated as painful, rectal pressure increased regional cerebral blood flow (rCBF) in areas commonly associated with somatic pain, including the anterior cingulate, insula, prefrontal cortex, thalamus, and cerebellum. Despite similar stimulus ratings in male and female patients, regional activations were much stronger for males. In both experiments, rectal pressure activated the insula bilaterally in males but not in females. Insula activation was associated most strongly with objective visceral pressure, whereas anterior cingulate activation was associated more with correlated ratings of subjective discomfort. The insula is discussed as a visceral sensory cortex. Several possible reasons for the insula gender effect are proposed.

Purpose To examine relationships following adjuvant chemotherapy between circulating proinflammatory cytokines, regional cerebral metabolism, and cognitive complaints in early stage breast cancer patients. Patients and Methods 33 breast cancer patients who had completed initial treatment (surgery, ± radiation, 23 chemotherapy, 10 no chemotherapy) obtained resting (18)F-FDG PET/CT brain imaging at baseline and one year later. Pro-inflammatory cytokine markers (IL-1ra, sTNF-RII, CRP, and IL-6) and cognitive complaints were also assessed at both time points. Results At baseline, consistent correlations were seen between the left medial frontal and right inferior lateral anterior temporal cortices and inflammatory markers within the chemotherapy group, and not in the group who did not receive chemotherapy. After one year, correlations persisted in the medial frontal cortex and the temporal cortex, the latter shifting superiorly. Both of these regional correlations demonstrated the highest levels of significance when looking across the one year time frame (IL-1ra: peak voxel p<0.0005; cluster size p<0.0005, p=0.001 after correction (medial prefrontal), p<0.0005; cluster size p=0.001, p=0.029 corr. (anterior temporal), sTNF-RII: p<0.0005; cluster size p=0.001, p=0.040 corr. (medial prefrontal)). Positive correlations were also seen within the chemotherapy group between baseline memory complaints and the medial frontal (p<0.0005; cluster size p<0.0005, p<0.0005 corr.) and anterior temporal (p<0.0005; cluster size p<0.0005, p=0.002 corr.) cortices at baseline and one year later. Conclusion Metabolism in the medial prefrontal cortex and anterior temporal cortex was found to correlate with both memory complaints and cytokine marker levels in chemotherapy patients.

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The effects of inadequate thyroid hormone availability to the brain on adult cognitive function are poorly understood. This study assessed the effects of hypothyroidism on cognitive function using a standard neuropsychological battery in 14 patients suffering from untreated hypothyroidism and complaining of subjective cognitive difficulties in comparison with 10 age-matched healthy comparison subjects. Significant differences between groups were limited to verbal memory retrieval as measured by the California Verbal Learning Test (CVLT). On short delay free recall, long delay free recall, and long delay cued recall, significant differences remained between groups despite the limited statistical power of this study. There were no significant results found between groups on attentional or nonverbal tasks. Results suggest that hypothyroid-related memory deficits are not attributable to an attentional deficit but rather to specific retrieval deficits.