Term
| What are the functions of the basal ganglia? |
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Definition
A. Movement control
1. Involved in the planning phase of a movement
2. Contributes to the speed of particular movements
3. Contributes to movements learned by repetition
B. May link motivation and emotion to the execution of movements. |
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Term
| What is the cortex-basal ganglia pathway? |
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Definition
| CORTEX→ BASAL GANGLIA→ THALAMUS→ CORTEX→ PYRAMIDAL and EXRAPYRAMIDAL TR. |
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Term
| How does a lesion of the subcortical basal ganglia present? |
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Definition
| abnormalities of movements that are disorganized and uncoordinated |
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Term
| What are the structures of the basal ganglia? |
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Definition
| caudate nucleus, the putamen and globus pallidus. Caudate + putamen = the striatum; putamen + globus pallidus = the lentiform nucleus. The other significant structures are also included because of proximity and fiber connections; the substantia nigra and the subthalamic nucleus. |
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Term
| What are the afferent connections? |
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Definition
| striatum, putamen, caudate nucleus, substantia nigra |
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Term
| The striatum receives excitatory information from ___________. |
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Definition
| cortex, thalamus and striatum nigra |
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Term
| The putamen receives inputs from ________. |
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Definition
| primary motor and sensory cortical areas |
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Term
| The caudate nucleus receives fibers from __________. |
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Definition
| association cortex- regions that are concerned with motor control and some mental function. |
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Term
| What is the important neurotransmitter fo the substantia nigra? |
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Definition
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Term
| The main efferent fibers of the basal ganglia are from the ___________. |
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Definition
| globus pallidus and substantia nigra (excitatory) |
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Term
| Where is information from the striatum processed? |
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Definition
| globus pallidus and substantia nigra |
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Term
| Basal ganglia efferents to the thalamus are inhibitory or excitatory? |
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Definition
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Term
| Fibers from the thalamus to cortex are inhibitory or excitatory? |
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Definition
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Term
| What is the key function of the basal ganglia? |
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Definition
| modulation of impulses that begin in the cortex and end up back in the cortex. |
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Term
| What is the subthalamic nucleus? |
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Definition
| part of a small but significant internal loop between the globus pallidus and the substantia nigra. |
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Term
| What is the key hypokinetic disorder discussed? |
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Definition
Parkinson’s disease- pronounced loss of dopamine in the striatum due to death of substantia nigra neurons. Characterized by akinesia, bradykinesia, lack of facial movements, increased muscle resting tone (rigidity) and involuntary rhythmic movements- resting tremor.
• cogwheel and pill rolling |
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Term
| What are the three hyperkinetic disorders? |
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Definition
| Huntington's, Hemiballismus, Tourette's |
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Term
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Definition
| (chorea) dominant/inherited disease with genetic defect found on chromosome 4 is due to loss of GABA neurons in the striatum and frontal lobe of cortex. Produces rapid, jerky involuntary movements of face, arms and legs coupled with rapid mental deterioration. Athetosis is closely related having similar but slower movements |
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Term
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Definition
| wild, flailing movements of arms and legs due to lesion in the subthalamic nucleus. |
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Term
| What is Tourette's syndrome? |
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Definition
| condition characterized by involuntary movements or tics occurring at regular intervals and/or explosive inappropriate vocalizations. Children affected often show hyperactivity and unusual creativity. Appears to be dopamine-related condition in the basal ganglia. |
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