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18 Cards in this Set
- Front
- Back
- 3rd side (hint)
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How are the cerebellum and basal ganglia related to the motor system |
They interact with different levels of the sensorimotor hierarchy. The coordinate and modulate. May permit maintenance of visually guided responses despite cortical damage. |
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Where does Cerebellum get input and feedback from? |
Gets input from primary and secondary motor cortexes and brainstem motor nuclei. Gets feedback from motor responses. |
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What is the function of the cerebellum? |
Motor control. Coordination, precision, accurate timing. Not necessary to basic elements of perception or movement. May also play a role in the fine-tuning and timing of cognitive responses. |
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What can occur from cerebellar lesions? |
Hypotonia (diminished resistance to passive limb displacements. Ataxia (problems in execution of voluntary movements, problems with rate and timing of movements) Tremor (most marked at the end of a movement) |
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What are the basal ganglia, and what do they modulate? |
They are a heterogenous collection of interconnected nuclei. Modulate motor output and cognitive functions, including learning. |
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From where do basal ganglia receive input and where do they send output? |
Part of neural loops that receive cortical input and send output back via the thalamus. |
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Disorders of the basal ganglia |
Parkinson's, Huntington's Hypokinesis and hyperkinesis |
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Hypokinesis |
Impaired initiation of movement, overactive inhibition, motor cortex understimulated Parkinson's |
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Hyperkinesis |
Excessive involuntary movements, underactive inhibition, motor cortex over-stimulated Huntington's |
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Parkinson's Disease, cause |
Degeneration and loss of dopamine producing neurons in the substantia nigra |
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Parkinson's Disease, symptoms |
Difficulty initiating movement, slowness of movement, shaking at rest, postural imbalance, rigidity, bradykinesia, tremor |
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Huntington's Disease, cause |
CAG repeat in Huntington gene, leading to polyglutamine expansion in protein. Leads to dysfunction and death in striatal neurons, 60% reduction in striatal area. |
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Huntington's Disease, symptoms |
Severe motor impairments (chorea, rigidity), progressive loss of mental abilities (concentration, memory), psychiatric problems (depression, dementia) |
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Does the sensorimotor system have patterns? |
Yes. All but the highest levels of the sensorimotor system have complex patterns of activity programmed into them, and complex movements are produced by activating these programs. Most of the individual responses that you make are performed without direct cortical involvement and you are often barely aware of them. The cerebellum and basal ganglia serve to coordinate the various programs. |
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How are central sensorimotor programs capable of motor equivalence? |
A given movement can be accomplished various ways using different muscles. Central sensorimotor programs must be stored at a level higher than muscle (as different muscles can do the same task). Sensorimotor programs may be stored in secondary motor cortex. |
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How can central sensorimotor programs be changes? |
Practice can generate and modify programs, such as by response chunking and shifting control to lower levels. |
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Response chunking |
Practice combines the central programs controlling the individual response. |
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Shifting control to lower levels |
Frees up higher levels to do more complex tasks and permits greater speed. |
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