Neuroscience
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It is well known that the preoptic-anterior hypothalamus (PO/AH), containing temperature-sensitive and -insensitive neurons plays an important role in precise thermoregulatory responses. Previous in vivo studies suggest that the arginine vasopressin (AVP) is an important endogenous mediator in thermoregulation, since AVP and V(1a) vasopressin receptor antagonist can induce hypothermia and hyperthermia, respectively. In the present study, intracellular electrophysiological activity was recorded from temperature-sensitive and -insensitive neurons in rat PO/AH tissue slices, using a whole-cell patch clamp. ⋯ V(1a) vasopressin receptor participated in these responses. Since excited warm-sensitive neurons or inhibited cold-sensitive and temperature-insensitive neurons promote heat loss or suppress heat production and retention. These results that AVP excites warm-sensitive neurons and inhibits cold-sensitive and temperature-insensitive neurons suggest a probable mechanism of AVP-induced hypothermia.
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One of the benefits musicians derive from their training is an increased ability to detect small differences between sounds. Here, we asked whether musicians' experience discriminating sounds on the basis of small acoustic differences confers advantages in the subcortical differentiation of closely related speech sounds (e.g., /ba/ and /ga/), distinguishable only by their harmonic spectra (i.e., their second formant trajectories). Although the second formant is particularly important for distinguishing stop consonants, auditory brainstem neurons do not phase-lock to its frequency range (above 1000 Hz). ⋯ By measuring the degree to which subcortical response timing differs to the speech syllables /ba/, /da/, and /ga/ in adult musicians and nonmusicians, we reveal that musicians demonstrate enhanced subcortical discrimination of closely related speech sounds. Furthermore, the extent of subcortical consonant discrimination correlates with speech-in-noise perception. Taken together, these findings show a musician enhancement for the neural processing of speech and reveal a biological mechanism contributing to musicians' enhanced speech perception in noise.
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Biochemical investigations have demonstrated that nitric oxide synthase (NOS) is distributed widely in the olfactory system. However, little is known about the action of NO at the synaptic level on identified neurons in local circuits that process chemosensory signals. Here, using whole-cell recordings, the effect of NO on cholinergic synaptic input to olfactory projection neurons (PNs) is determined in the Drosophila antennal lobes (ALs), which has become an excellent model for studying early olfactory-processing mechanisms. ⋯ The effect of SNP on the frequency of mEPSCs could be eliminated by ODQ as well. Thus, these results suggest that elevated NO concentration decreased cholinergic synaptic input to PNs in a sGC-dependent manner. In this way, NO signaling is suited to fulfill a regulatory role to effectively fine-tune network activity in Drosophila ALs.
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Receptor interacting protein (RIP)-1 kinase activity mediates a novel pathway that signals for regulated necrosis, a form of cell death prominent in traumatic and ischemic brain injury. Recently, we showed that an allosteric inhibitor of RIP-1 kinase activity, necrostatin-1 (Nec-1), provides neuroprotection in the forebrain following neonatal hypoxia-ischemia (HI). Because Nec-1 also prevents early oxidative injury, we hypothesized that mechanisms involved in this neuroprotection may involve preservation of mitochondrial function and prevention of secondary energy failure. ⋯ Up-regulation of glial fibrillary acidic protein (GFAP) following HI was also prevented by Nec-1 treatment. No differences by gender were observed. We conclude that Nec-1 immediately after HI, is strongly mitoprotective and prevents secondary energy failure by blocking early NO• accumulation, glutathione oxidation and attenuating mitochondrial dysfunction.
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The central medial nucleus (CM) of thalamus is a prominent cell group of the rostral intralaminar complex of the thalamus. No previous report in the rat has comprehensively described the projections of CM. Using the anterograde anatomical tracer, Phaseolus vulgaris leucoagglutinin, we examined the efferent projections of CM, comparing projections from rostral (CMr) and caudal (CMc) regions of CM. ⋯ Main CMc subcortical projection sites were the dorsal striatum and the lateral, central, anterior cortical, and basomedial nuclei of amygdala. The largely complementary output of CMr and CMc to diverse areas of cortex and to regions of the striatum and amygdala suggest a combined CM influence over a widespread area of the anterior cortex and throughout the dorsal and ventral striatum and the amygdala. CM projections to limbic and sensorimotor structures of the rostral forebrain suggest that CM may serve to integrate affective, cognitive and sensorimotor functions for goal-directed behavior.