Thin dendrites of cerebellar interneurons confer sublinear synaptic integration and a gradient of short-term plasticity.
Interneurons are critical for neuronal circuit function, but how their dendritic morphologies and membrane properties influence information flow within neuronal circuits is largely unknown. We studied the spatiotemporal profile of synaptic integration and short-term plasticity in dendrites of mature cerebellar stellate cells by combining two-photon guided electrical stimulation, glutamate uncaging, electron microscopy, and modeling. Synaptic activation within thin (0.4 μm) dendrites produced somatic responses that became smaller and slower with increasing distance from the soma, sublinear subthreshold input-output relationships, and a somatodendritic gradient of short-term plasticity. Unlike most studies showing that neurons employ active dendritic mechanisms, we found that passive cable properties of thin dendrites determine the sublinear integration and plasticity gradient, which both result from large dendritic depolarizations that reduce synaptic driving force. These integrative properties allow stellate cells to act as spatiotemporal filters of synaptic input patterns, thereby biasing their output in favor of sparse presynaptic activity.
Institut Pasteur, Unit of Dynamic Neuronal Imaging, 25 Rue du Dr Roux, 75724 Paris Cedex 15, France.
SourceNeuron 73:6 2012 Mar 22 pg 1159-72
Excitatory Amino Acid Antagonists
Excitatory Postsynaptic Potentials
Microscopy, Electron, Transmission
Potassium Channel Blockers
Sodium Channel Blockers
Pub Type(s)In Vitro
Research Support, Non-U.S. Gov't