Neuroreport
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The present study examined the sleep-wake cycle effects of microinjections of yohimbine, an adrenergic antagonist, and atropine, a cholinergic antagonist, into the cerebral ventricle of clomipramine-induced depressed rats. Yohimbine microinjection caused a significant reduction in the total duration and the number of REM sleep episodes compared to control saline injections. Atropine microinjection caused a significant reduction in the total duration and the number of REM sleep episodes without changing the REM sleep latency compared to control saline microinjection. These results show for the first time that the REM sleep disturbances observed in clomipramine-treatment induced depressed rats can be attenuated by increasing and decreasing the brain noradrenergic and cholinergic activities, respectively.
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In the auditory cortex, primitive features of acoustic stimuli are represented for auditory scene analysis. A typical example of a feature representation is the tonotopic map, in which sound frequencies are spatially arranged in an orderly manner. Some neurons in the auditory cortex are sensitive to sound source location, which is another important feature for auditory scene analysis. ⋯ The observed arrangements of sound frequencies were consistent with those obtained by electrophysiological mapping, which indicates that our intrinsic optical recording can visualize populational responses of neurons. We also found different temporal patterns of intrinsic signals elicited in response to contralateral, ipsilateral, and bilateral ear stimulations. Finally we try to explain the observed differential time courses of intrinsic signal responses from the theoretical point of view on the conduction of neural activities, based on the so far anatomically identified neural pathways in the rodent auditory system.