Nature neuroscience
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Nature neuroscience · Aug 2014
ReviewDirect and indirect pathways of basal ganglia: a critical reappraisal.
The basal ganglia are subcortical nuclei controlling voluntary actions and have been implicated in Parkinson's disease (PD). The prevailing model of basal ganglia function states that two circuits, the direct and indirect pathways, originate from distinct populations of striatal medium spiny neurons (MSNs) and project to different output structures. These circuits are believed to have opposite effects on movement. ⋯ Accordingly, we propose a model in which intrastriatal connections are critical and the two pathways are structurally and functionally intertwined. Thus, all MSNs might either facilitate or inhibit movement depending on the form of synaptic plasticity expressed at a certain moment. In PD, alterations of dopamine-dependent synaptic plasticity could alter this coordinated activity.