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PRODID:-//Memento EPFL//
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SUMMARY:A compound mechanism of deprivation-mediated sensory surround pote
 ntiation in the adult somatosensory cortex
DTSTART:20121101T133000
DTEND:20121101T143000
DTSTAMP:20260428T021502Z
UID:1ba53f557c6d6ce3f041ef19a6e953e8e1069bd8b15fcd1891c3cf1d
CATEGORIES:Miscellaneous
DESCRIPTION:Frédéric GAMBINO\, Neurosciences Fondamentales\, Uni Geneva\
 nFunctional maps in the cerebral cortex reorganize in response to changes 
 in experience. After a partial sensory deprivation\, spared inputs often e
 xpand their cortical representations whereas the deprived cortical modalit
 ies shrink. The synaptic underpinnings of this map plasticity remain uncer
 tain. We demonstrate that within the lemniscal\, ventral posterior medial 
 (VPm) thalamic nucleus-associated pathway\, layer (L) 2/3 pyramidal cell s
 ynapses in mouse barrel cortex can be potentiated upon pairing of whisker-
 evoked post-synaptic potentials (PSPs) with action potentials. This spike-
 timing dependent long-term potentiation (STD-LTP) was only effective for P
 SPs evoked by deflections of a whisker in the neuron’s receptive field c
 enter\, and not its surround. Trimming of all except two whiskers\, which 
 increases L2/3 spiking and causes the spared whisker representations to me
 rge\, rapidly opened the possibility to drive STD-LTP by the spared surrou
 nd whisker. This facilitated STD-LTP was associated with a strong and spec
 ific decrease in the surrounding whisker-evoked inhibitory conductance and
  partially occluded picrotoxin-mediated LTP facilitation. The deprivation 
 also increased the activity of a non-specific paralemniscal L2/3 synaptic 
 pathway\, which is relayed in the posterior medial (POm) thalamic nucleus.
  Taken together\, our data demonstrate that the experience-dependent expan
 sion of receptive fields in the barrel cortex may be promoted by disinhibi
 tion-mediated and spike-timing dependent potentiation of a lemniscal surro
 und whisker-specific pathway as well as by the gating of a non-specific pa
 ralemniscal pathway.
LOCATION:SG 0213 http://plan.epfl.ch/?room=sg0213
STATUS:CONFIRMED
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