Formation and plasticity of inhibitory synapses

Abstract:

Multiple forms of synaptic plasticity co-exist in the brain, endowing it with its outstanding capacity to adapt and learn, while maintaining an operational activity level at the same time. During all these changes, balancing excitation and inhibition is crucial. Most of our knowledge of synaptic plasticity comes from studying excitatory synapses, while inhibitory synapses remain more enigmatic. We are using two�photon laser�scanning microscopy to examine the formation and plasticity of inhibitory synapses between GFP-expressing GABAergic axons and dendrites of CA1 pyramidal cells in hippocampal slice cultures.

We have recently demonstrated that GABAergic axons are capable of forming new synaptic contacts at a timescale of several hours. These contacts occur exclusively through the formation of new GABAergic boutons at pre-existing axon-dendrite crossings. We are currently investigating how formation and disassembly of inhibitory boutons is affected by neuronal activity.