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1. What regions are responsible for motor decisions and motivations?
2. What region do they influence?
- 1. Association and Limbic Cortex
- 2. Influence Premotor Cortical Areas
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1. What regions are responsible for planning/organizing movement?
2. What region do they influence?
- 1. Premotor cortical areas (LPA, SMA)
- 2. Influence primary motor cortex
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Which thalamic nuclei are involved in basal ganglia influence of the premotor areas?
VA, VL
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Which thalamic nucleus is involved in cerebellar influence of the premotor and primary motor areas?
VL
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Which primary motor cortex cells synapse directly in the spinal cord?
Giant Betz cells - monosynaptic pathway
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What is the difference between direct and indirect motor pathways?
Indirect pathways synapse on nuclei in the brainstem, which projects to the spinal cord
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Locations in spinal cord and targets of:
1. Direct pathways
2. Indirect pathways
- 1. Lateral descending pathways - distal muscles
- 2. Medial descending pathways - axial/proximal muscles
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Primary Motor Cortex:
1. Function?
2. Organization?
3. Lesion symptoms?
- 1. Voluntary Muscle Control
- 2. Organized according to movement components
- 3. Contralateral UMN paralysis (spastic)
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Lateral Premotor Area:
1. Function?
2. Location?
3. Lesion symptoms?
- 1. Plans/initates voluntary movements triggered by external sensory cues2. Ant. to precentral gyrus, lateral side
- 3. Impairment in performing tasks in response to sensory cues
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Supplementary Motor Area:
1. Function?
2. Location?
3. Lesion symptoms?
- 1. Plans/initiates voluntary movements initiated by internal guidance2. Ant. to precentral gyrus, medial side
- 3. General reduction of voluntary movements, difficulty in spontaneous speech
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Frontal Eye Fields:
1. Function
2. Location?
3. Lesion symptoms?
- 1. Voluntary/memory-guided eye movements to contralateral side
- 2. Ant. to precentral gyrus, inf. to lateral premotor area
- 3. Eyes directed to side of lesion
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What are the direct motor pathways?
- Lateral Corticospinal Tract
- Anterior Corticospinal Tract
- Corticobulbar Tract
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What are the indirect motor pathways?
- Corticorubral Pathway
- Corticoreticular Pathways
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Lateral Corticospinal Tract:
1. Origin?
2. Decussation?
3. Target?
- 1. Motor and sensory areas
- 2. Crosses at spinomedullary junction
- 3. Distal muscles
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Anterior Corticospinal Tract:
1. Origin?
2. Decussation?
3. Target?
- 1. Motor and sensory areas
- 2. Crosses at segmental spinal levels
- 3. Proximal/Axial muscles
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Corticobulbar Tract:
1. Origin?
2. Target?
- 1. Head area of primary motor cortex
- 2. Lower face musculature (crossed), other V, VII, XII bilateral
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Corticorubral Pathway:
1. Origin?
2. Termination?
3. Activated pathway --> target?
- 1. Upper limb area of primary motor cortex
- 2. Ipsilateral red nucleus
- 3. Rubrospinal pathway --> distal upper limb
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Corticoreticular Pathway:
1. Origin?
2. Termination?
3. Activated pathway --> target?
- 1. Lateral PMA, SMA
- 2. Reticular Nuclei
- 3. Reticulospinal pathway --> proximal muscle (fixation/stabilization)
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