ABSTRACT
The cerebral cortex is interconnected with two major subcortical structures: the basal ganglia and the cerebellum. How and where cerebellar circuits interact with basal ganglia circuits has been a longstanding question. Using transneuronal transport of rabies virus in macaques, we found that a disynaptic pathway links an output stage of cerebellar processing, the dentate nucleus, with an input stage of basal ganglia processing, the striatum.
Subject(s)
Basal Ganglia/anatomy & histology , Cerebellum/anatomy & histology , Neural Pathways/anatomy & histology , Animals , Basal Ganglia/virology , Cerebellum/metabolism , Cerebellum/virology , Macaca , Neural Pathways/virology , Rabies virus/physiologyABSTRACT
Motion in the visual scene is processed by direction-selective neurons in primary visual cortex. These cells receive inputs that differ in space and time. What are these inputs? A previous single-unit recording study in anesthetized monkey V1 proposed that the two major streams arising in the primate retina, the M and P pathways, differed in space and time as required to create direction selectivity. We confirmed that cortical cells driven by P inputs tend to have sustained responses. The M pathway, however, as assessed by recordings in layer 4Calpha and from cells with high contrast sensitivity, is not purely transient. The diversity of timing in the M stream suggests that combinations of M inputs, as well as of M and P inputs, create direction selectivity.
