Mechanisms for synapse specificity during striatal long-term depression.

Endocannabinoid (eCB)-mediated forms of long-term synaptic plasticity occur in several brain regions, but much remains unknown about their basic properties and underlying mechanisms. Here, we present evidence that eCB-mediated long-term depression (eCB-LTD) at excitatory synapses on medium spiny neurons in the striatum requires presynaptic activity coincident with CB1 receptor activation. This dual requirement for CB1 activation and presynaptic activity is a mechanism by which eCB-LTD may be made synapse specific.