Movement and Parkinson's Disease Flashcards
Area 6 of the brain contains which two areas which are important in planning motor movement?
Lateral premotor area and medial supplementary area
Movement originates in cortical layer 5 of the primary motor cortex in which pyramidal neuron cells?
Betz cells
The major subcortical input to the PMA and SMA arise from a nucleus of the dorsal thalamus - the ventrolateral nucleus. Where does input to this nucleus arise from?
The basal ganglia
What are the functions of the basal ganglia?
The voluntary selection and initiation of higher functions
scaling the output of motor responses
projects to frontal eye fields to control saccadic eye movements
may have a role in memory relating to body orientation
The caudate nucleus and putamen contain identical cell types. T/F?
True
The corpus striatum of the basal ganglia receives somatotropin information from…?
Motor, sensory, association and limbic areas and the intrealaminar nuclei of the thalamus
What is the name for the connection between the corpus striatum, internal Globus pallidus and thalamus?
Direct pathway
The corticostriate projection is topographically and functionally organised so that the putamen is chiefly concerned with motor control and the caudate nucleus with…?
Eye movements and cognition
There is a bidirectional communication between the sub thalamic nucleus and the internal Globus pallidus. T/F?
False - this bidirectional connection is between the sub thalamic nucleus and the external Globus pallidus
Which part of the substantia nigra projects to the thalamus (ventrolateral and ventroanterior nuclei) to promote thalamus projections to the cortex?
Pars reticulata
Which part fo the substantial nigra projects onto the corpus striatum?
Pars compacta
Describe the direct corticostrital loop?
The corpus striatum inhibits the internal Globus pallidus to reduce the ability of the GPi to inhibit the thalamus. This effectively encourages the thalamus to fire and stimulates the cortex
Describe the indirect corticostital loop?
Corpus striatum output inhibits the external Globus pallidus which reduces the inhibition of the sub thalamic nucleus which then excites the internal Globus pallidus and the pars reticulata of the substantial nigra to inhibit the thalamus. the cortex therefore gets less stimulation
Lesions of the basal ganglia produce extrapyramidal signs. Give examples of these types of signs
Tremor
Rigidity
Dyskinesia
From which amino acid are dopamine, noradrenaline and adrenaline synthesised?
Tyrosine
Which enzyme is involved in the first stage of dopamine synthesis, conversion of tyrosine to L-DOPA (L-dihydroxyphenylalanine)?
Tyrosine hydroxyls
In which areas of the brainstem are dopaminergic neurons located?
Substantia nigra
Ventral tegmentum area
The ventral tegmentum area uses dopaminergic signalling. What is the function of this area?
Circuitry involved in reward, motivation and emotion
The ventral tegmentum is involved in pathways for reward, motivation and emotion. As such, which structures does it project to?
Nucleus accumbens Ventral striatum prefrontal cortex amygdala hippocampus hypothalamus olfactory tubercle
Where in the brainstem are neurons which use noradrenaline as their principal neurotransmitter clustered?
Pons, fourth ventricle and lateral tegmentum
What is the main function of noradrenergic neurons in the CNS?
Modulate attention, arousal, mood and pain
What neurotransmitter is used by the raphe nuclei?
Serotonin
Which amino acid is serotonin produced form?
Tryptophan
What are the functions of serotogenic neurons in the CNS?
Regulation of mood, appetite and pain
modulation of pain, state of wakefulness, aggression and some cognitive functions such as memory and learning
Which enzyme converts L-DOPA to dopamine?
DOPA-decarboxylase
When dopamine is release, about 50% is taken up again and transported into vesicles for storage and release. The remaining dopamine enters the neural terminal and is destroyed by which enzyme?
Monoamine oxidase
When dopamine is released in the synaptic cleft some of the dopamine is taken up again by the pre-synaptic neuron (reuptake 1), some is destroyed by enzymes on the post-synaptic neural terminal and some is taken up by the effector cell (reuptake 2). What percentage of the dopamine released from the pre-syanptic neuron is taken up by the post-synaptic neuron (reuptake 2)?
10%
Which enzyme in the post-synaptic cell degrades dopamine which has been taken up by the cell in reuptake 2?
Catchol-O-methyltransferase
Describe the tuberohypophyseal dopaminergic pathway?
Neurons from the ventral hypothalamus run to the median eminence and release dopamine to inhibit prolactin secretion by the anterior pituitary
Renal vasodilation and increased myocardial contractility in the periphery is mediated by what type of dopamine receptor?
D1
What type of dopamine receptor exists in the limbic system but not in the corpus striatum?
D3