Van Leeuwenhoek Lecture on Bionanoscience - Gene Block (Los Angeles): 'Aging and the biological clock'



16:00 hrs


Gorlaeus laboratories 04.28 LUMY


Gene Block is a biologist, from 2007 on he is chancellor of the University of California.

He attended Stanford University for his BA, and subsequently received his MS and PhD in psychology from the University of Oregon (1975).

He was professor of biology at the University of Virginia (1978-2007).

Blocks early work with mollusks investigated the structure and function of basal retinal neurons (BNR) in circadian photoentrainment. He was the first to discover a cell-autonomous circadian pace-maker and concluded that BRNs are both necessary and sufficient for photoentrainment.

Later he explored the molecular basis of circadian rhythms in mammanls, and found that calcium flux was necessary for circadian rhythmicity.At present his work is focused on the effect that aging has on the circadian clock.


Aging exerts a profound effect on physiology and behavior. One important impact of aging is on sleep and wakefulness. Aged humans and other mammals show decreases in the quality and duration of sleep, as well as an inability to adjust promptly to alterations in the sleep cycle brought about by rotating shiftwork, transmeridian flight and even daylight savings time.

Age-related changes in the physiology of the circadian system governing sleep and wakefulness are being studied through the use of mammalian models, primarily mice. The central clock of the otherwise distributed chronobiologic system is the Suprachiasmatic Nucleus (SCN), a dense collection of approximately 10.000 neurons, bilaterally represented at the base of the hypothalamus. The SCN expresses an intrinsic circadian rhythm in multi-unit electrical activity both in vivo, as revealed by deep brain recording, and in vitro in brain slice. The SCN plays a critical but not exclusive role in controlling the timing, duration and, most likely, the quality of sleep. Research conducted over the last decade is beginning to reveal the system, circuit and neuron-specific changes that occur during aging.

At the level of the SACN, aging reduces the amplitude of the circadian rhythm of multi---unit electrical activity. In young animals, electrical recordings from brain slices containing the SACN exhibit high levels of neuronal impulses during the time interval that corresponds tp prior daytime and significantly lower levels of electrical activity during the interval corresponding to nighttime. The reduction in circadian amplitude