Miscellaneous

What are the direct and indirect neural pathways?

What are the direct and indirect neural pathways?

For the basal ganglia to work, nearly the entire cerebral cortex projects onto the striatum. The striatum then projects onto the thalamus, and from there neurons head back to the cerebral cortex through two pathways: the direct pathway – which is excitatory – and the indirect pathway, which is inhibitory.

What happens during the direct pathway?

The direct pathway funnels the information from the striatum to GPi/SNr via GABAergic inhibitory projections thus selectively reducing its activity and releasing firing from the thalamocortical neurons to initiate the movement.

What offers a direct pathway to the brain?

The direct pathway passes through the caudate nucleus, putamen, and globus pallidus, which are parts of the basal ganglia. It also involves another basal ganglia component the substantia nigra, a part of the midbrain.

Is the thalamus inhibitory or excitatory?

The thalamus receives inhibitory afferents from the thalamic reticular nucleus (TRN) as well as from extrathalamic sources. These two types of inhibition display major differences in connectivity, synaptic organization and physiology suggesting distinct functions.

What is the function of the indirect pathway through the basal ganglia?

The indirect pathway, sometimes known as the indirect pathway of movement, is a neuronal circuit through the basal ganglia and several associated nuclei within the central nervous system (CNS) which helps to prevent unwanted muscle contractions from competing with voluntary movements.

What does dopamine do to indirect pathway?

Dopamine differentially modulates the response of direct and indirect pathway neurons to glutamate, facilitating transmission in the direct pathway by its actions on D-1 receptors and inhibiting indirect pathway transmission by stimulation of D-2 receptors.

Does dopamine inhibit indirect pathway?

Dopamine (DA) release from the substantia nigra pars compacta (SNc) causes an excitation in the direct pathway via activation of DA (D)-1 receptors and an inhibition in the indirect pathway via D2 receptors. Therefore, DA is required for movement to occur.