Graduate Studies Faculty

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Research

A selective evolutionary advantage seems to be conferred on individuals whose physiological rhythms are synchronized to environmental conditions. Thus, the majority of organisms studied show twenty-four hour rhythms in physiological processes termed circadian rhythms. Disturbances in circadian rhythms are known to contribute to a variety of diseases and to impair mental and physical performance. The circadian system consists of three conceptual components, a timekeeping oscillator, input pathways providing environmental information, and output pathways sending timing information to peripheral clocks and organs. The timekeeping oscillator or clock resides, in mammals, in the suprachiasmatic nucleus (SCN) a bilateral structure located in the hypothalamus. This circadian clock is synchronized (entrained) to the environmental light-dark cycle via a direct axonal projection (retinohypothalamic tract, RHT) from a specialized subset of retinal ganglion cells. SCN neurons ouput timing information via projections to other hypothalamic nuclei and by releasing neurohumoral factors.

The long-term goal of our research is to understand the functional properties of SCN neurons and how the circadian clock regulates these properties. To reach this goal we are pursuing four lines of research:

• Cellular electrophysiology of the suprachiasmatic nucleus
• Regulation of retinal input to the SCN
• Role of intracellular Ca²⁺ as a signaling molecule in the circadian system
• Characterization of the retinal ganglion cells projecting to the SCN

Recent Publications

Education

• Ph.D., University of Texas Health Sciences Center, Dallas, 1981

Previous Positions

Non-Academic Interests