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BACKGROUND Circadian rhythms in mammalian behavior, physiology, and biochemistry are controlled by the central clock of the suprachiasmatic nucleus (SCN). The clock is synchronized to environmental light-dark cycles via the retino-hypothalamic tract, which terminates predominantly in the ventral SCN of the rat. In order to understand synchronization of the(More)
The circadian pacemaker of the suprachiasmatic nucleus (SCN) functions as a seasonal clock through its ability to encode day length [1-6]. To investigate the mechanism by which SCN neurons code for day length, we housed mice under long (LD 16:8) and short (LD 8:16) photoperiods. Electrophysiological recordings of multiunit activity (MUA) in the SCN of(More)
Circadian rhythms in neuronal ensemble, subpopulations, and single unit activity were recorded in the suprachiasmatic nuclei (SCN) of rat hypothalamic slices. Decomposition of the ensemble pattern revealed that neuronal subpopulations and single units within the SCN show surprisingly short periods of enhanced electrical activity of approximately 5 h and(More)
The suprachiasmatic nuclei (SCN) of the hypothalamus contain a pacemaker that generates circadian rhythms in many functions. Light is the most important stimulus that synchronizes the circadian pacemaker to the environmental cycle. In this paper we have characterized the baseline neuronal firing patterns of the SCN as well as their response to light in(More)
The suprachiasmatic nuclei (SCN) of the hypothalamus continue to oscillate when they are isolated in a brain slice preparation. We recorded multiunit activity in the SCN of the rat both in vivo and in vitro to determine the circadian discharge pattern. The variability of the discharge pattern is larger and the amplitude of the rhythm is smaller in vivo than(More)
The suprachiasmatic nucleus (SCN) of the anterior hypothalamus contains a major circadian pacemaker that imposes or entrains rhythmicity on other structures by generating a circadian pattern in electrical activity. The identification of "clock genes" within the SCN and the ability to dynamically measure their rhythmicity by using transgenic animals open up(More)
The mammalian master clock driving circadian rhythmicity in physiology and behavior resides within the suprachiasmatic nuclei (SCN) of the anterior hypothalamus. Circadian rhythms are generated by a set of clock genes via intertwined negative and positive autoregulatory transcription-translation feedback loops. The Cryptochrome 1 and 2 genes are(More)
4-Aminopyridine (4-AP) induced 2 types of spontaneous field potentials (SFPs) in the hippocampal slice. Type I resembled spontaneous activity induced by other convulsants. They occurred at a rate of approximately 1 Hz, started in the CA2/CA3 region and spread at a velocity of 0.3 m/s to area CA1. Transsection experiments and laminar profiles indicated that(More)
The effect of glucose on the electrical potential profile in the stripped goldfish intestine was measured and analyzed in terms of cell membrane electromotive forces. In substrate free conditions, the mucosal membrane potential difference ψmc averaged −54 mV, cell interior negative. The addition of 27.8 mMd-glucose to the mucosal side of the epithelium(More)