M2 Cortex-Dorsolateral striatum stimulation reverses motor symptoms and synaptic deficits in Huntington’s Disease

Huntington’s disease (HD) is a neurological disorder characterized by motor disturbances. HD pathology is most prominent in the striatum, the central hub of basal ganglia. The cortex is the main striatal afference and progressive cortico-striatal disconnection characterizes HD. We mapped cortico-striatal dysfunction in HD mice to ultimately modulate the activity of selected cortico-striatal circuits to ameliorate motor symptoms and recover synaptic plasticity. Multimodal MRI in vivo suggested prominent functional network deficits in fronto-striatal compared to motor-striatal pathways, which were accompanied by reduced glutamate levels in the striatum of HD mice. Moreover, optogenetically-stimulated glutamate release from fronto-striatal terminals was reduced in HD mice and electrophysiological responses in striatal neurons were blunted. Remarkably, repeated M2 Cortex-dorsolateral striatum optogenetic stimulation normalized motor behavior in HD mice and evoked a sustained increase of synaptic plasticity. Overall, these results reveal that the selective stimulation of fronto-striatal pathways can become an effective therapeutic strategy in HD.