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18 Cards in this Set
- Front
- Back
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What movement related info is processed in the cerebellum?
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Proprioceptive information (posn of body part)
Muscle tone Vestibular Info (posn of body in space) Environment |
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What movement related info is processed in the basal ganglia?
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Decision to move
Direction of movement Amplitude of movement (proceduralization -making movements more efficient) |
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Where is the emotional content of movement processed?
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Cerebellum and basal ganglia information originating from limbic system
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What are three main circuits of the basal ganglia?
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Motor circuit -controls body and eye movement
Associative circuit -involved in higher level cognitive function Limbic Circuit -emotional and motivational processing |
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What are two other functions of the basal ganglia?
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Modulation of voluntary motor activity
Balance of inhibitory and excitatory pathways gives input to the thalamus and from there to the cortex |
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What is the direct pathway in the release inhibition model?
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Release of the tonic inhibition of the thalamus, which leads to more excitation of the motor cortex and measured movement (target orientated movement)
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What is the indirect pathway of the release inhibition model?
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Inhibits output from the thalamus so less excitation of the motor cortex and less movement.
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What steps is the Direct pathway comprised of?
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Excitation-from cortex to striatum (caudate +putamen)
Inhibition -from striatum to Globus Pallidus Internus (GPi) Inhibition- from GPi to the thalamus Inhibition of Inhibition allows more excitation from the thalamus to the primary motor cortex ---finally increased movement -the striatum is also influenced by excitation from the substantia nigra pars compacta (SNc) which enhances excitatory input from the cortex |
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What steps is the Indirect pathway composed of?
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Excitation from the cortex of the striatum
Inhibition from striatum to GPe (globus pallidus externus) Inhibition from the Gpe to the subthalamic nucleus (STN) Excitation from the STN to the GPi Excitation from the GPi to the thalmus So we have exciation of inhibition in the GPi which results in less excitement from the thalums to the cortex -at same time substantia nigra pars compacta projects inhibitory neurons to the striatum which counteract the original excitatory neurons of the cortex |
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What is ballism?
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Hyperkinetic movement disorder characterized by flinging movements of the extremities.
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What is the underlying pathophysiology of ballism?
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Loss of the contralateral (usually unilateral...hemibalism) subthalamic nucleus. Loss of this affects the indirect pathway by loss of excitation from STN to the GPi which means less inhibition of the thalamus, which results in more excitation of the cortex and more movement.
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What are some characteristics of Huntington's Disease?
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Deficits in cognition, behaviour and a characteristic hyperkinetic movement disorder.
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What is the pathophysiology of Huntington's Disease?
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Marked degeneration of the striatum (caudate and putamen) and temporal and frontal association cortices.
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How does degeneration of the striatum cause hyperkinetic movement?
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Primarily by decreasing the indirect pathway at the striatum(direct pathway decreases to a lesser degree)
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What is Parkinson's disease?
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A hypokinetic motor disorder characterised by a decrease in movement or a loss of movement (Rigidity, akinesia, tremors, shuffling gait)
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What is the pathophysiology of parkinson's diseaes?
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Degeneration of dopaminergic neurons in the substantia nigra.
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How does the loss of dopaminergic neurons in the substantia nigra cause hypokinesia?
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Direct pathway -normally these dopaminergic neurons enhance input from the cortex, so there is less amplification of these signals inthe striatum
Indirect pathway -dopamingergic neurons from the SNc have an inhibitory influence on the striatum which is decreased so that the indirect pathway becomes more predominant which means less movement |
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What are two treatment options for Parkinson's disease?
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L-Dopa
Deep brain stimulation of the subthalamic nucleus |
