Modulation of Movement by Basal Ganglia and Cerebellum

The Basal Ganglia (B.G.) and the Cerebellum (Cb) will ____ but not ___?

Modulate UMN

Not generate movement

The BG will do what?

Specialized movements

The Cb will?

Modulate routine movements

What is the direct pathway of the Basal ganglia?

cortex --> striatum --> GP INternal segment -> thalamus -> cortex

What is the indirect pathway of the Basal ganglia?

Cortex-> Stratum -> Globus pallidus -> Subthalmic nuclei -> GP internal segment -> Thalamus -> cortex

What is disinhibition?

"Inhibiting an inhibitor" with the net effect being excitation

The direct pathway will ____ thalamic excitation of the cortex?

The indirect pathway will _____ thalamic excitation of the cortex?

Increase

Decrease

Glutamate will ____ the thalamus

GABA will ____ the thalamus?

Increase excitation

Inhibit excitation

DA will be ____ in the striatum in the __ _pathway?

DA will be ____ in the striatum in the __ _pathway?

This leads to an overall ___ in thalamic input to the cortex?

Excitatory; direct

Inhibitory; indirect

Increase

Ash will be ____ in the striatum in the __ _pathway?

ACh will be ____ in the striatum in the __ _pathway?

This leads to an overall ___ in thalamic input to the cortex?

Inhibittory; direct

excitatory; indirect

decrease

Damage to the basal nuclei will lead to?

Hyperkinesia (Indirect inj) or Hypokinsia (Direct inj) depending on what is inj.

A cerebellar lesion can lead to what?

Ataxia, no impairment to movement or strength

Cb allows for ___ _of fine motor movements?

Unconscious control / allow fro error corrections and adjustments in posture

Molecular layer?

Outer layer of the cerebellum - few neurons integrative area

Granule cell layer?

Innermost layer of the cerebellar rich in cell bodies

perkinjie cells?

Large cells between molecular and granule layers

____ fibers are found in the spinal cord, brain stem, or cortex?

Mossy fibers (Afferent)

____ are found in the medulla receiving signals from the vestibular tract?

Climbing fibers (Afferent)

What are interneurons?

Weight the comparisons w/ recurrent loops

What is the efferent cells of the Cb circuits?

Purkinje cells - send information from UMN

What is the vestibulocerebellum responsible for?

Coordinated movements of eyes and head.

Antigravity muscle control

What will we see if we have damage to the vestibulocerebellum system?

Ataxia

poor balance

wide gate

What is the spinocerebellum for?

Proper execution of coordinated movements

What will we see if the spinocerebellum is damaged?

Dysmerita,

Functional tremor

Decreased muscle tone

What is the function of the cerebrocerebellum?

Planning, initiation timing

Learning motor skills

Properly timed movements

What are symptoms of a patient w/ cerebellar lesion?

Wide gate

Ataxia

Dysmetra

Asynergia

Intention tremor

Nystagmus

Head bobbing

A Cb lesion prior to desiccation can cause ipsilasteral motor deficits because?

It decussates on 2 different levels