Editors' ChoiceNeuroscience

Sleep and Memory

Science Signaling  07 Apr 2009:
Vol. 2, Issue 65, pp. ec119
DOI: 10.1126/scisignal.265ec119

Sleep is a biological process that is necessary for survival not only in vertebrates but also in Drosophila. Sleep is crucial for the consolidation of memories and is responsive to waking experience. Donlea et al. found that core circadian clock neurons play an important role in mediating experience-dependent changes in sleep need in fruit flies. Use-dependent changes in sleep need were dependent upon the expression of the Drosophila homolog of serum response factor in a specific subset of clock neurons. Within these neurons, serum response factor altered experience-dependent changes in sleep by targeting epidermal growth factor receptor signaling. Experience-dependent changes in sleep were associated with an increase in the number of synaptic terminals in specific neuronal circuits. Moreover, the number of synaptic terminals was reduced during sleep, and this decline was prevented by sleep deprivation. In an independent study, Gilestro et al. found that, in two different strains of Drosophila, levels of pre- and postsynaptic markers increased after sleep deprivation independent of time of day and gender. One of these synaptic markers increased after sleep deprivation in areas of the fly brain linked to memory and learning. Thus, in support of the synaptic homeostasis hypothesis of sleep, an important function of sleep, even in invertebrates, may be synaptic downscaling.

J. M. Donlea, N. Ramanan, P. J. Shaw, Use-dependent plasticity in clock neurons regulates sleep need in Drosophila. Science 324, 105–108 (2009). [Abstract] [Full Text]

G. F. Gilestro, G. Tononi, C. Cirelli, Widespread changes in synaptic markers as a function of sleep and wakefulness in Drosophila. Science 324, 109–112 (2009). [Abstract] [Full Text]