The effect of preparatory activity on the processing of behaviourally relevantstimuli. (360G-Wellcome-102372_Z_13_A)

The mossy fibre synapse projects from granule cells in the dentate gyrus and permits powerful excitatory drive balanced by feedforward and feedback inhibition via interneurons. Granule cells display a diverse portfolio of firing patterns that correspond to particular behavioural states. Since very little is known about the variety of feedforward and feedback inhibitory pathways, we are unable to assess how the mossy fibre synapse filters different input patterns. In vitro recordings from CA3 pyramidal cells and interneurons during mossy fibre stimulation will be used to estimate parameters for a computational model of short term plasticity of the synapses in these circuits as well as their modification by neuromodulator transmitters. This model will then be used to make powerful predictions about how the balance between excitatory and inhibitory inputs to CA3 pyramidal cells processes natural stimulus patterns from granule cells. These predictions will then be verified by further in vitro experiments to provide some insight into how this unique synapse operates and can be modulated in vivo.