Basal Ganglia

Basal Ganglia: STR: [blank_start]Striatum[blank_end] GP: [blank_start]Globus Pallidus[blank_end] STN: [blank_start]Subthalamic nucleus[blank_end] SNr: [blank_start]Substantia nigra pars reticulata[blank_end]

Basal ganglia

Box and arrow model

Pathways

Function: Hyperdirect pathway: [blank_start]STOP (-)[blank_end] Direct pathway: [blank_start]GO (+)[blank_end] Indirect pathway: [blank_start]NO-GO (-)[blank_end]

The [blank_start]striatum[blank_end] is the main input region for the basal ganglia.

Dorsal striatum: [blank_start]Caudate nucleus[blank_end] + [blank_start]putamen[blank_end] Ventral striatum: [blank_start]Nucleus accumbens[blank_end] + [blank_start]olfactory tubercle[blank_end]

Medium spiny neurons with D1 and D2 receptors can be found in the [blank_start]striatum[blank_end]. D1 neurons project to the [blank_start]direct[blank_end] pathway. D2 neurons project to the [blank_start]indirect[blank_end] pathway

Medium spiny neurons in the striatum show a preference for the [blank_start]contralateral[blank_end] side.

In the classical model the globus pallidus is believed to be the [blank_start]relay[blank_end] of the striatum.

Globus pallidus internal: [blank_start]medial[blank_end] Globus pallidus external: [blank_start]lateral[blank_end]

The subthalamic nucleus is part of the

The subthalamic nucleus

The [blank_start]substantia nigra pars reticulata[blank_end] and the [blank_start]globus pallidus internal[blank_end] are the main output structures of the basal ganglia. Output typically consists of [blank_start]GABAergic[blank_end] projections to the [blank_start]thalamus[blank_end].

Substantia nigra pars compacta: - [blank_start]Input[blank_end] - [blank_start]dopamin[blank_end]ergic Substantia nigra pars reticulata: - [blank_start]Output[blank_end] - [blank_start]GABA[blank_end]ergic

The term "convergence of information" means that there are [blank_start]less[blank_end] neurons in regions further down the processing pathway.

Which one is true?

Movement initiation: There is a sharp [blank_start]increase[blank_end] in the firing rate of medium spiny neurons in the [blank_start]striatum[blank_end]. This leads to a sharp [blank_start]decrease[blank_end] in the firing of output neurons in the [blank_start]substantia nigra pars reticulata[blank_end]. This in turn releases inhibition in target neurons, e.g. the [blank_start]superior colliculus[blank_end] for eye movement.

Parkinson's disease is characterized by the loss of [blank_start]dopaminergic[blank_end] neurons in the [blank_start]substantia nigra pars compacta[blank_end]. This leads to a lack of [blank_start]excitation[blank_end] of the direct pathway and a lack of [blank_start]inhibition[blank_end] on the indirect pathway, which results in [blank_start]slow[blank_end] movements. Another result is [blank_start]hyperactivity[blank_end] in the subthalamic nucleus.

The [blank_start]subthalamic nucleus[blank_end] is the only basal ganglia region with glutamatergic projections.