Researchers establish brain pathway linking motivation, addiction and disease

Amazing stuff! There you have it, one single pathway!

""We are exploring a direct communication between two major components of our brain's movement system, which is absent from neuroscience textbooks. These systems are traditionally thought to function independently," ...

In their study ... reported the first direct evidence that the two systems are intertwined—showing the cerebellum modulates basal ganglia dopamine levels that influence movement initiation, vigor of movement and reward processing. ..."

From the abstract:

"Evidence of direct reciprocal connections between the cerebellum and basal ganglia has challenged the long-held notion that these structures function independently. While anatomical studies have suggested the presence of cerebellar projections to the substantia nigra pars compacta (SNc), the nature and function of these connections (Cb–SNc) is unknown. Here we show, in mice, that Cb–SNc projections form monosynaptic glutamatergic synapses with dopaminergic and non-dopaminergic neurons in the SNc. Optogenetic activation of Cb–SNc axons in the SNc is associated with increased SNc activity, elevated striatal dopamine levels and increased locomotion. During behavior, Cb–SNc projections are bilaterally activated before ambulation and unilateral lever manipulation. Cb–SNc projections show prominent activation for water reward and higher activation for sweet water, suggesting that the pathway also encodes reward value. Thus, the cerebellum directly, rapidly and effectively modulates basal ganglia dopamine levels and conveys information related to movement initiation, vigor and reward processing."

Researchers establish brain pathway linking motivation, addiction and disease

Researchers Establish Brain Pathway Linking Motivation, Addiction and Disease (New Jersey Institute of Technology)

The cerebellum directly modulates the substantia nigra dopaminergic activity (no public access)