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28 Cards in this Set
- Front
- Back
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How are purposeful movements generated? |
Cortical influences on motor activity use the basal nuclei as part of assembling the patterns of neural activity
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What are the basal nuclei used with to generated movements and behaviors
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With supplementary motor cortex to store "programs" of motor activty
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What are the major parts of the basal nuclei? |
Striatum (Caudate nucleus and putamen)
Pallidum (globus pallidus) Substantia nigra Subthalamic nucleus |
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What are the loops of the basal nuclei? |
From motor cortex to striatum to globus pallidus to thalamus and back to motor cotrex areas |
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What side does the basal ganglia influence? |
Within the hemisphere on the side of the motor cortex it controls |
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What do the two primary neural circuits control? |
Activity of the motor cortex and movement |
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What is the specific function of the primary neural circuits of the basal nuclei? |
One acts generally to stimulate movement (hyperkinesis) while the other acts to inhibit it (hypokinesis) |
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Describe the direct pathway |
From cortex to striatum to the globus pallidus to the thalamus and then back to the cortex - Facilitates activity in the motor cortex |
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Describe the indirect pathway? |
Similar to Direct Pathway and includes subthalamic nucleus Inhibits activity in the motor cortex |
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What is the substantia nigra involved in? |
The balance of activity of these two pathways |
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Where is the output of the basal ganglia? |
Through the corticospinal and corticonuclear tracts and through connections to postural and locomotor centers in the brainstem |
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Why are the corticonuclear to brainstem pathways particularly important |
Because the basal ganglia have a large part of their influence on posture and muscle tone |
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What are the cerebellum and deep cerebellar nuclei used for? |
As a short loop feedback programmers of motor activity in which motor related sensory input is processed as feedback to modulate motor activity |
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What is the effect of a disturbance of the cerebellum? |
Disruption of the coordination of motor a ctivity |
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What is the flocculonodular lobe? |
Receives information from the vestibular apparatus and vestibular nuclei and affects balance primarily through the vestibulospinal tracts |
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Where does the vermis and paravermal regions receive information from? |
Spinocerebellar tracts and motor cortex -- affects posture, some balance and eye movements.
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How does the vermis and paravermal regions affect posture and balance? |
Through influences on the axial body musculature primarily through the reticulospinal and rubrospinal tracts, but also by connections back to motor cortex |
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Where does the lateral cerebellar hemispheres receive most of their input? |
From the pons and indirectly the motor cortex |
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What does the Lateral Cerebellar Hemispheres affect? |
The plannign of motor activity largery for the upper limb, through connections back to motor cortex through the thalamus |
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How are influences of the cerebellum expressed? |
Through the pyramidal system and rubrospinal, reticulospinal, and vestibulospinal tracts |
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What do lesions of the cerebellum produce? |
Symptoms ipsilateral to lesions |
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The connections of the cerebellum are such that |
Inputs are on the same side of the body as the cerebellar hemis phere Outputs are generally to the same side as well for brainstem tracts, but to the contralateral motor cortex |
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What is the result of the inputs and outputs of the cerebellum? |
Cerebellar influences on movement are ipsilateral |
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What do disturbances of the corticonuclear and corticospinal tracts produce? |
Deficits contralateral to the lesion if the lesions is above the level of the pyramidal decussation and ipsilateral to the lesion if it is in the spinal cord |
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What other tracts are important to motor function? |
Rubrospinal tracts Vestibulospinal tracts Reticulospinal tracts |
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What is the significance of the rubrospinal tracts? |
Crossed to arm flexors |
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What is the significance of the vestibulospinal tracts? |
Both ipsilateral and contralateral to excite primarily extensors. Largely controlled by the vestibular apparatus and cerebellum, does have indirect cortical influences |
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What is the significance of the reticulospinal tracts? |
Originate in the medulla and pons but are under control by cerebral cortex and cerebellum Effect postural muscles |
