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SUMMARY:Synaptic plasticity and sleep in Drosophila - Giorgio F. Gilestro\
 , University of Wisconsin Madison\, USA
DTSTART:20100224T110000Z
DTEND:20100224T120000Z
UID:TALK23503@talks.cam.ac.uk
CONTACT:Dr Michael Hastings
DESCRIPTION:Sleep is a universally conserved behavior whose function still
  remains elusive. Our lab recently proposed a model for sleep function tha
 t links sleep need to the homeostatic regulation of synaptic strength\, in
  a mutual bi-directional fashion. Using Drosophila as model system\, we an
 alyzed both directions of this connection.\n\nUsing two different molecula
 r markers of synapse number (the structural proteins BRP and DLG) and thre
 e markers of synaptic function (the components of vesicle secretion machin
 ery: SYN\, SYX\, CSP) we investigated how sleep and wakefulness affect the
  dynamic regulation of bona fide synaptic strength in the Drosophila brain
 . We found that prolonged wakefulness induces a diffuse increase in synapt
 ic number/volume\, while restorative sleep has the opposite effect. Using 
 two different paradigms of sleep deprivation we showed that the increase i
 s specific to and correlate with the amount of time the flies spend being 
 awake. Conversely\, sleep-induced decrease in synaptic markers is proporti
 onal to the amount of time flies spend asleep and it is independent from c
 ircadian entrainment. Using confocal imaging\, we showed that the increase
  in the expression of synaptic markers is widespread across the entire bra
 in and that it correlated with a volumetric increase in specific area of t
 he brain involved in learning.\n\nTo manipulate synaptic function and stre
 ngth\, we ectopically expressed genes known to increase or decrease synapt
 ic activity in vivo. We showed that a widespread increase in synaptic numb
 er in the Drosophila brain induces an increase in sleep drive and that\, c
 onversely\, a decrease in synaptic number is followed by a decrease in sle
 ep time. In particular\, manipulation of synaptic activity (whether pan-ne
 uronally or in specific area of the brain) affects length of sleep time\, 
 quality of sleep and recovery after sleep deprivation.\n\nIn conclusion\, 
 our results suggest that\, in flies\, sleep regulates synaptic strength dy
 namics and synaptic strength regulates sleep need.
LOCATION:MRC LMB: Neurobiology Division Seminar Room (Level 2)
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