Flashcards
Motor System - Basal nuclei
Cards in this deck (47)
- 1What are the structures which make up the basal nuclei?Caudate nucleus + Putamen (Striatum)
Globus pallidus (internal + external = lentiform nucleus)
Substantia nigra
Subthalamic nucleus
Claustrum - not necessary
Amygdala - not necessary - 2What is the primary function of the basal nuclei?Unkown
- 3What is one of the most important functions of the basal nuclei?Relays information between body muscles and areas of the cerebral cortex that are involved in motor control.
- 4What are the other four functions of the basal nuclei?1) Selecting appropriate movements - procedural learning or habits - when it goes wrong you get ticks etc
2) Initiating internally generated movements (initiating centre) - voluntary movement and eye movements.
3) Planning and executing complex motor strategies
4) Non-motor cognition and emotion behaviour - 5BN function - what is action selection?Determines which behaviours to execute.
- 6How do the basal nuclei affect control and co-ordination?Give smooth voluntary movements.
- 7What kind of influence does the basal nuclei have on motor systems?Inhibitory influence on motor systems.
- 8How does 'behaviour switching' occur?Connections with lots of brain areas.
- 9Where does information enter the striatum?From the cortex.
- 10Describe the indirect pathway?Striatum -- inhibit Gpe-- disinhibit STN -- excite Gpi-inhibit thalamus
- 11Describe the direct pathwaystriatum--inhibit GPi--disinhibits thalamus
- 12Where do the sensory and motor areas feed into?Putamen (striatum)
- 13Where do the association and frontal eye field of the cortex feed into?Caudate nucleus (striatum)
- 14Describe the corticostriatal pathway?From PMC, SMA to striatum to the thalamus and back to the motor cortex and SMA. Activate corticobulbar pathways and corticospinal pathway (activation of pyramidal cells).
- 15What type of pathway is the corticostriatal pathway?Extrapyramidal
- 16Which two areas of the cortex don't feed directly into the basal nuclei?Primary visual cortex
Primary auditory cortex - 17Why are symptoms associated with basal nuclei damage so broad?Because lots of the cortex feeds into the basal nuclei and have functions incorporated in it.
- 18How are the striations of the striatum formed?Anterior limb of the internal capsule cuts between the caudate nucleus and putamen.
- 19What are striosomes?Cell bodies intricately spread among striatum - where information comes in from cortex - function together to give output to globus pallidus.
- 20What are the majority of neurons in the basal nuclei? What type of neurotransmitter do they use.Medium spiny neurons (95%).
GABAergic - 21What type of activity does the GP show (especially GPi) ?Tonic inhibitory
- 22How does striatal neuron activity vary with movement.Usually silent - period just before movement (where info from cortex is sent to striatal movement) striatal neurons fire (initiation)
- 23Describe the direct pathway. What is it therefore responsible for?Striatum --- SNR (substantia nigra pars reticular) and GPi (disinhibits thalamus)
Increases movement. - 24Why is there massive convergence from the striatum to the thalamus?Enhance/amplify signal.
- 25What affect does the direct pathway have on the basal nuclei output?Causes it to decrease.
- 26Other than the GPi what does the STN activate in the indirect pathway?SNr (substantia nigra reticular)
- 27How does the indirect pathway affect movement and basal nuclei output?Inhibits movement.
Increases basal nuclei output. - 28Which pathway is naturally dominant?Indirect
- 29What effect does the substantia nigra pars compacta have on the striatum?Increases activation of direct pathway.
- 30How does the substantia nigra pars compacta have different effects on the two pathways?Dopamine increases transmission along the direct pathway via D1 receptors. Decreases activation of the indirect pathway via D2 receptors.
- 31What clinical effects would you expect to with dysfunction of basal nuclei?Tremor at rest
Chorea - brisk graceful movements
Athetosis - slow writhing movements
Ballism - wild swinging movements
Tics - small, repeated movements - 32What are dyskinesias?Abnormal involuntary movements
- 33What is dystonia?Abnormalities of muscle tone.
- 34What type of disorder is Parkinson's disease? Why does it happen?Hypokinetic disorder
Degeneration of of substantia pars compacta neurons and ventral tegmental area neurons.
Dopamine deficiency in forebrain - 35What are the three main symptoms of parkinson's?1) Absence/slowness of movement (akinesia)
2) Stiffness or rigidity
3) Tremor at rest - 36What type of disorder is Huntington's disease? Where does the primary pathology occur?Hyperkinetic disorder.
Primary pathology in the striatum and cortical pathways. - 37Which neurons are lost in huntington's? What does this lead to?Striatal GABAergic neurons and Cholinergic neurons.
Loss of inhibitory influence on thalamus. - 38What symptoms do you see with Huntington's?Chorea and dementia.
- 39What causes Huntington's disease?Autosomal dominant inheritance (Htt gene)
- 40What treatments are available?Anti-dopaminergic drugs.
- 41What type of disorder is hemiballism? What does it result from?Hyperkinetic disorder. Results from damage (vascular lesion) to the subthalamic nucleus.
- 42What type movements can be seen in (hemi)ballism? When is it hemi?Ballistic movements - violent, flinging movements of extremities/contralateral limbs. When it occurs on one side of the body.
- 43Why are these ballistic movements seen?STN is excitatory to GPe which suppresses the thalamus/movements. Suppression is lost.
- 44What are the drug treatments for ballism?Anti-epileptic (short-term), Dopamine blockers (anti-psychotics)
- 45What are the underlying causes of ballism that can be treated?Infection/hyperglycaemia
- 46What symptoms are seen with Tourette's symptoms? What is the cause? Which structures are involved?Tics, involuntary and sometimes obscene vocalisations.
Unclear cause - genetic and environmental factors.
Dysfunction in the thalamus, basal nuclei and frontal cortex. - 47How can Tourette's be treated?Anti-psychotic drugs
Behavioural and psychological therapy/
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- Degree Neurophysiology Flashcards on Motor System - Basal nuclei, created by Anna mph on 28/12/2015.
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