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Although stress-induced increases in inflammation have been implicated in several major disorders, including cardiovascular disease and depression, the neurocognitive pathways that underlie inflammatory responses to stress remain largely unknown. To examine these processes, we recruited 124 healthy young adult participants to complete a laboratory-based social stressor while markers of inflammatory activity were obtained from oral fluids. A subset of participants (n = 31) later completed an fMRI session in which their neural responses to social rejection were assessed. As predicted, exposure to the laboratory-based social stressor was associated with significant increases in two markers of inflammatory activity, namely a soluble receptor for tumor necrosis factor-[alpha] (sTNF[alpha]RII) and interleukin-6 (IL-6). In the neuroimaging subsample, greater increases in sTNF[alpha]RII (but not IL-6) were associated with greater activity in the dorsal anterior cingulate cortex and anterior insula, brain regions that have previously been associated with processing rejection-related distress and negative affect. These data thus elucidate a neurocognitive pathway that may be involved in potentiated inflammatory responses to acute social stress. As such, they have implications for understanding how social stressors may promote susceptibility to diseases with an inflammatory component. anterior cingulate | insula | inflammation | depression | disease doi/ 10.1073/pnas.1009164107

Auditory stream segregation (or streaming) is a phenomenon in which 2 or more repeating sounds differing in at least 1 acoustic attribute are perceived as 2 or more separate sound sources (i.e., streams). This article selectively reviews psychophysical and computational studies of streaming and comprehensively reviews more recent neurophysiological studies that have provided important insights into the mechanisms of streaming. On the basis of these studies, segregation of sounds is likely to occur beginning in the auditory periphery and continuing at least to primary auditory cortex for simple cues such as pure-tone frequency but at stages as high as secondary auditory cortex for more complex cues such as periodicity pitch. Attention-dependent and perception-dependent processes are likely to take place in primary or secondary auditory cortex and may also involve higher level areas outside of auditory cortex. Topographic maps of acoustic attributes, stimulus-specific suppression, and competition between representations are among the neuropbysiological mechanisms that likely contribute to streaming. A framework for future research is proposed. Keywords: auditory scene analysis, attention, auditory cortex, tonotopic organization, neural suppression

The forebrain, including the amygdala (AM) and hypothalamus, may be a higher brain center that modulates the activity of a brainstem neural system that influences ingestive behavior via descending projections. In this study, to elucidate the characteristics of sensory information processing in the forebrain in relation to this putative connection, we recorded neuronal activity in the AM and hypothalamus [lateral hypothalamic area (LHA), medial hypothalamic area (MHA)] of rats during discrimination of conditioned sensory stimuli and the ingestion of various tastant solutions. Of 420 responsive AM neurons identified, 24 were taste responsive and located mainly in the central nucleus of the AM. Multivariate analyses of these taste neurons suggested that in the AM, taste quality is processed on the basis of palatability. In the hypothalamus, of 282 LHA and MHA neurons recorded, 144 responded to one or more conditioned auditory stimuli and/or licking of one or more solutions. Stress, which is known to influence feeding behavior, increased the mean spontaneous activity of LHA neurons but decreased the mean spontaneous neuronal activity of MHA neurons. This pattern of changes in spontaneous neuronal activity correlated with alterations in feeding behavior during stress. Furthermore, the activity of both AM and LHA neurons was modulated flexibly during conditioned associative learning. Together, the data suggest that the activity of the AM and hypothalamic neurons is altered when animals must modulate ingestive behavior by learning a new stimulus associated with food and by being exposed to stress, suggesting that these forebrain areas are important modulators of the activity of a basic neural system in the brainstem that influences ingestive behavior. J. Nutr. 130: 954S-959S, 2000. KEY WORDS: * rats * hypothalamus * amygdala * taste * ingestive behavior