Basal ganglia facts for kids
The basal ganglia (or basal nuclei) are three areas under the cerebral cortex. They are part of the cerebrum (forebrain), and connected to the midbrain and the thalamus. They are vital to movement, and damage here results in damaged ability to move.
The three areas are:
- striatum
- caudate nucleus
- putamen
- pallidum (or globus pallidus)
- substantia nigra
- nucleus accubens
- subthalamic nucleus
The range of behaviours controlled by the nuclei is wide. They control eye movements. They do voluntary motor control, learning procedures for routine behaviors or "habits", and cognitive emotional functions.
The basal ganglia also control motivation. They select actions, that is, the choice of what to do at a given time. Experimental studies show that the basal ganglia inhibit (suppress) a number of motor systems. A release of this inhibition lets a motor system act. This "behaviour switching" is influenced by signals from many parts of the brain, including the prefrontal cortex, which plays a key role in doing things.
Evolution
The basal ganglia form one of the basic components of the forebrain, and can be recognized in all species of vertebrates. Even in the lamprey (one of the most primitive vertebrates) striatal, pallidal, and nigral elements can be identified by their anatomy and histochemistry.
Images for kids
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Coronal slices of human brain showing the basal ganglia. White matter is shown in dark gray, gray matter is shown in light gray. Anterior: striatum, globus pallidus (GPe and GPi) Posterior: subthalamic nucleus (STN), substantia nigra (SN)
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Basal ganglia
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Connectivity diagram showing excitatory glutamatergic pathways as red, inhibitory GABAergic pathways as blue, and modulatory dopaminergic pathways as magenta. (Abbreviations: GPe: globus pallidus external; GPi: globus pallidus internal; STN: subthalamic nucleus; SNc: substantia nigra pars compacta; SNr: substantia nigra pars reticulata)
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Connectivity of the basal ganglia as revealed by diffusion spectrum imaging based on thirty subjects from the Human Connectome Project. Direct, indirect and hyperdirect pathways are visualized in different colors (see legend). Subcortical structures are rendered based on the Harvard-Oxford subcortical thalamus as well as the Basal Ganglia atlas (other structures). Rendering was generated using TrackVis software.
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The left side of Fig.1 shows a region of the prefrontal cortex receiving multiple inputs from other regions, as cortico-cortical activity. The input from B is the strongest of these. The right side of Fig. 1 shows the input signals also being fed to the basal ganglia circuitry. The output from here, back to the same region, is shown to modify the strength of the input from B, by adding strength to the input from C thereby modifying the strongest signal from B to C. (Thalamic involvement is implicit but not shown).
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Basal ganglia highlighted in green on coronal T1 MRI images
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Basal ganglia highlighted in green on sagittal T1 MRI images
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Basal ganglia highlighted in green on transversal T1 MRI images
See also
In Spanish: Ganglios basales para niños
