Basal Nuclei

What is another name for the basal nuclei of the telencephalon?

Ganglia basalia or ganglia telencephalica

What is the main role of basal nuclei described in the lecture?

Control of movement

What structures form the striatum or neostriatum?

Nucleus caudatus and putamen

What structure forms the pallidum or paleostriatum?

Globus pallidus

Which basal-nuclei division is phylogenetically more recent?

Striatum

Which basal-nuclei division is phylogenetically older?

Pallidum

What is the predominant neuronal morphology in the striatum?

Small fusiform neurons

What larger neurons are dispersed within the striatum?

Large multipolar neurons

What is the predominant neuronal morphology in the pallidum?

Large multipolar neurons

Which structure is subordinate to the neostriatum?

Pallidum

Where is the ventral striatum located?

Inferomedial part of the head of the nucleus caudatus

Which nucleus is contained within the ventral striatum?

Nucleus accumbens

What type of activity is associated with the ventral striatum?

Subcortical motor activity with limbic-system involvement

Which midbrain structure modulates basal-nuclei activity?

Substantia nigra

What is another name for the subthalamic nucleus?

Nucleus of Luys

What is the major cortical input to the neostriatum?

Corticostriatal fibers

From which cortical region do corticostriatal fibers arise especially prominently?

Somatosensitive cortex

Are most corticostriatal fibers unilateral or bilateral?

Bilateral

Which thalamic nuclei give rise to thalamostriatal fibers?

Intralaminar nuclei of the ipsilateral thalamus

Through which structure do thalamostriatal fibers reach the neostriatum?

Internal capsule

Which part of the substantia nigra gives rise to nigrostriatal fibers?

Pars compacta

What neurotransmitter is used by nigrostriatal fibers?

Dopamine

Which brainstem nuclei provide reticulostriatal fibers?

Serotonergic raphe nuclei

What neurotransmitter is associated with reticulostriatal fibers?

Serotonin

Are neostriatal efferents ipsilateral or contralateral?

Ipsilateral

What is the principal neurotransmitter of neostriatal efferents?

GABA

Are neostriatal efferents excitatory or inhibitory?

Inhibitory

Where do striatopallidal fibers terminate?

Globus pallidus

Where do striatonigral fibers terminate?

Substantia nigra pars reticularis

What is the major input from the neostriatum to the pallidum?

Striatopallidal fibers

What is the subthalamic input to the pallidum called?

Subthalamo-pallidal fibers

Which tract carries subthalamo-pallidal fibers?

Fasciculus subthalamicus

What are the major pallidal outputs collectively called?

Pallidofugal fibers

Which thalamic nuclei receive pallidothalamic fibers?

Ventral anterior and ventral lateral nuclei

Which three fiber systems convey pallidothalamic fibers?

Ansa lenticularis, fasciculus lenticularis, and fasciculus thalamicus

Where do pallidosubthalamic fibers terminate?

Subthalamic nucleus

Which tract carries pallidosubthalamic fibers?

Fasciculus subthalamicus

Where do pallidotegmental fibers terminate?

Reticular formation of the pontine tegmentum

What is the sequence of the cortico-striato-pallido-thalamo-cortical circuit?

Cortex to striatum to pallidum to thalamus to premotor and motor cortex

What is the neurotransmitter effect of corticostriatal fibers?

Excitatory glutamatergic

What is the neurotransmitter effect of striatopallidal fibers?

Inhibitory GABAergic

What is the neurotransmitter effect of pallidothalamic fibers?

Inhibitory GABAergic

Which cortical regions receive thalamocortical output from the basal-nuclei circuit?

Premotor and motor cortex

What is the function of the striato-nigro-striatal circuit in the lecture?

Inhibition of the neostriatum

Which nigral division receives striatonigral inhibitory input?

Substantia nigra pars reticularis

Which nigral division supplies dopaminergic input to the neostriatum?

Substantia nigra pars compacta

What is the effect of dopamine acting at D1 receptors in the neostriatum?

Excitatory

What is the effect of dopamine acting at D2 receptors in the neostriatum?

Inhibitory

What relationship defines the pallido-subthalamo-pallidal circuit?

Reciprocal connection between pallidum and subthalamic nucleus

What is the striatum's role in movement planning?

Planning voluntary and automatic movements

Which cortical regions cooperate with the striatum in movement planning?

Premotor, motor, and limbic cortex

What motor information is stored by the striatum?

Learned motor programs

What is the pallidum's role in motor control?

Execution of postural and skilled motor activity

Which structures modulate basal-ganglia activity in movement and muscle-tone regulation?

Substantia nigra, thalamus, subthalamus, and reticular formation

What is the effect of the neostriatum on muscle tone according to the lecture?

Increases muscle tone

What is the effect of the pallidum on muscle tone according to the lecture?

Decreases muscle tone

What pathological change causes reduced nigrostriatal dopaminergic activity in Parkinson disease?

Degeneration of substantia nigra

What happens to striatal activity when nigrostriatal dopamine is insufficient?

It becomes excessive

What motor signs result from excessive striatal activity in Parkinson disease?

Muscle rigidity and bradykinesia

What neurons degenerate in Huntington chorea according to the lecture?

GABAergic striatal inhibitory neurons

What happens to nigrostriatal dopaminergic activity after degeneration of striatal inhibitory neurons?

It becomes excessive

What happens to pallidal activity in Huntington chorea according to the lecture?

It becomes excessive

What motor consequence is associated with excessive pallidal activity in Huntington chorea?

Decreased muscle tone with hyperkinesis