Topic: circadian clock

Profound changes in the visual environment occur over the course of the day-night cycle. There is therefore a profound pressure for cells and circuits within the visual system to adjust their function over time, to match the prevailing visual environment. Here, I will discuss electrophysiological data collected from nocturnal and diurnal rodents that reveal how the visual code is ‘temporally optimised’ by 1) the retina’s circadian clock, and 2) a change in behavioural temporal niche.

Neurons in the suprachiasmatic nucleus (SCN, the brain’s master circadian clock) display a 24 hour cycle in the their rate of action potential discharge whereby firing rates are high during the light phase and lower during the dark phase. Although it is generally agreed that this cycle of activity is a key mediator of the clock’s neural and humoral output, surprisingly little is known about how changes in clock electrical activity can mediate scheduled physiological changes at different times of day. Using opto- and chemogenetic approaches in mice we have shown that the onset of electrical act

Sleep and all of the other circadian rhythms that adapt us to the 24 hour world are controlled by the suprachiasmatic nucleus (SCN), the brain's central circadian clock. And yet, the SCN consists of only 20,000 neurons and astrocytes, so what makes it such a powerful clock, able to set the tempo to our lives? Professor Hastings will consider the cell-autonomus and neural circuit-level mechanisms that sustain the SCN clock and how it regulates rest, activity and sleep.

Organisms sense light for purposes that range from recognizing objects to synchronizing activity with environmental cycles. What mechanisms serve these diverse tasks? This seminar will examine the specializations of two cell types. First are the foveal cone photoreceptors. These neurons are used by primates to see far greater detail than other mammals, which lack them. How do the biophysical properties of foveal cones support high-acuity vision? Second are the melanopsin retinal ganglion cells, which are conserved among mammals and essential for processes that include regulation of the circadi