Circadian clock

Circadian clock gene expression in various midbrain areas plays a central role in the regulation of behavior, including reward-related processes, affective states, and motor functioning. Specifically, recent work has revealed a sex-specific effect of Bmal1 expression in the striatum on voluntary alcohol consumption in mice: suppression in males and augmentation in females. Interestingly, Bmal1 expression in the nucleus accumbens, a striatal subregion known for its role in mediating reward processes, inhibits alcohol consumption in both males and females, thus indicating that other striatal sub

The suprachiasmatic nucleus (SCN) is the central circadian clock, governing physiological processes through its output to the subparaventricular zone (SPZ). We investigated functional synaptic connectivity between the SCN and the SPZ neurons in mouse brain slices and we studied the effects of peptides expressed in the SCN on the SPZ neurons. Photostimulation of SCN neuromedin-S (NMS) neurons or the vasoactive intestinal peptide (VIP) neurons induced opto-evoked inhibitory post-synaptic currents (oIPSCs) in 60% and 50% of recorded SPZ neurons, respectively. These responses were mediated by GABA

…They are a consequence of the circadian clock individual periods. Cortisol is a key mediator for the rhythmic expression of circadian signals in almost all tissues and strictly regulated by the hypothalamic-pituitary-adrenal (HPA) axis. Diseases affecting HPA signaling might therefore have important consequences on chronotype and connected performance.20 patients with autoimmune adrenilitis and 40 control subjects of comparable age (54.53±18.42 vs 48.56±15.5 years) and sex (14f/6m vs 32f/8m) were asse

…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