A di-synaptic projection from the lateral cerebellar nucleus to the laterodorsal part of the striatum via the central lateral nucleus of the thalamus in the rat

We have examined a cerebello–thalamo–striatal pathway from the lateral cerebellar nucleus (LCN) to the laterodorsal part of the striatum (LDS) through the central lateral nucleus (CL) using light and electron microscopy through the employment of a combination of anterograde and retrograde tracing techniques. Biotinylated dextran amine (BDA) was injected into the unilateral LCN, and used as an anterograde tracer. Cholera toxin B subunit (CTb), used for light microscopy, and wheat germ agglutinin–horseradish peroxidase (WGA-HRP), used for electron microscopy, were injected into the contralateral LDS as retrograde tracers. Light microscopic analysis showed a good overlap of the distribution of BDA-labeled axon terminals and CTb-labeled neurons in the middle third of the CL in both dorsoventral and rostrocaudal axes on the LDS injection side. Electron microscopy confirmed the presence of direct synaptic contacts between BDA-labeled terminals and WGA-HRP-labeled dendrites in the CL.