Short-term regulation of information processing at the corticoaccumbens synapse
Journal of Neuroscience. 2005-12-14; 25(50): 11504-11512
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1. J Neurosci. 2005 Dec 14;25(50):11504-12.
Short-term regulation of information processing at the corticoaccumbens synapse.
Casassus G(1), Blanchet C, Mulle C.
(1)Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5091,
Institut François Magendie, Université Victor Segalen-Bordeaux II, 33077
In relation to expectation and delivery of reward, pyramidal neurons of the
prefrontal cortex either switch from a single spiking mode to transient phasic
bursting, or gradually increase their sustained tonic activity. Here, we examined
how switching between firing modes affects information processing at the
corticoaccumbens synapse. We report that increasing presynaptic firing frequency
in a tonic manner either depresses or facilitates synaptic transmission,
depending on initial probability of release. In contrast, repeated bursts of
stimulation of cortical afferents trigger a new form of short-term potentiation
of synaptic transmission (RB-STP) in the nucleus accumbens (NAc). RB-STP involves
the regulation of axonal excitability mediated by 4-AP-sensitive potassium
channels in afferent cortical neurons. Thus, in a tonic mode, information flow is
tightly controlled by regulatory mechanisms at the level of presynaptic
terminals, whereas switching to a bursting mode reliably enhances efficacy of
information processing for all cortical afferents to NAc neurons.
PMID: 16354908 [Indexed for MEDLINE]