Dopamine D1/D2 modulation of synaptic plasticity in the prefrontal cortex
© Kyle et al; licensee BioMed Central Ltd. 2009
Published: 13 July 2009
It is widely assumed that dopamine plays a crucial role in reinforcement learning due to the ability of dopamine neurons to signal reward prediction errors. However, it is not clear how such a signal could affect neurons in the prefrontal cortex and whether or not the experimentally demonstrated effects of dopamine on long-term synaptic plasticity are by themselves be enough to cause the animal to learn to predict future rewards. The aim of this study was to investigate the effect of dopamine modulation on synaptic plasticity via both the D1 and D2 dopamine receptors.
In this study, the effect of dopamine modulation on synaptic plasticity was determined by simulating a selection of plasticity protocols under both control conditions and a simulated bath of D1 or D2 agonists. The effects of dopamine D1 and D2 agonists on both intrinsic and synaptic parameters of PFC neurons were quantified using data obtained from in vitro recordings. In addition to the effects of dopamine on the single neuron f/I curve, D1 agonists enhanced calcium influx, NMDA and GABAA currents in the model whilst reducing the effect of AMPA conductances. D2 agonists acted oppositely on calcium influx and synaptic conductances. Changes in synaptic efficacy were quantified using an existing calcium-based model of synaptic plasticity .
This article is published under license to BioMed Central Ltd.