Direct Glutamatergic Signaling From Midbrain Dopaminergic Neurons Onto Pyramidal Prefrontal Cortex Neurons

The dopaminergic neurons of the ventral tegmental area (VTA) have been identified with the ability to co-release dopamine and glutamate. This ability was first documented in the nucleus accumbens but showed to be absent in the dorsal striatum. Recently the ability to release glutamate from a subpopulation of the VTA dopaminergic neurons has been shown to control the prefrontal cortex (PFC) excitation through the exclusive innervation of GABAergic fast spiking interneurons. Here, using an optogenetic approach, we expand this view by presenting that the VTA dopaminergic neurons do not only innervate interneurons but also pyramidal PFC neurons. This finding opens the range of possibilities for the VTA dopaminergic neurons to modulate the activity of PFC

The deep cerebellar nuclei to striatum disynaptic connection contributes to skilled forelimb movement

Summary: Cerebellar-thalamo-striatal synaptic communication has been implicated in a wide range of behaviors, including goal-directed actions, and is altered in cerebellar dystonia. However, its detailed connectivity through the thalamus and its contribution to the execution of forelimb movements is unclear. Here, we use trans-synaptic and retrograde tracing, ex vivo slice recordings, and optogenetic inhibitions during the execution of unidirectional or sequential joystick displacements to demonstrate that the deep cerebellar nuclei (DCN) influence the dorsal striatum with a very high probability. We show that this mainly occurs through the centrolateral (CL), parafascicular (PF), and ventrolateral (VL) nuclei of the thalamus, observing that the DCN→VL and DCN→CL pathways contribute to the execution of unidirectional forelimb displacements while the DCN→PF and DCN→thalamo→striatal pathways contribute to the appropriate execution of forelimb reaching and sequential displacements. These findings highlight specific contributions of the different cerebellar-thalamo-striatal paths to the control of skilled forelimb movement