Lecture 12 Flashcards
Define the following and relate to respective lesions.
Athetosis
Athetosis: continuous spontaneous writhing movements of the hand, arm, neck or face
Lesions in globus pallidus
Define the following and relate to respective lesions.
Hemiballismus
Hemiballismus: Sudden flailing movements of an entire limb
lesions in the subthalamic nuclei
Define the following and relate to respective lesions.
Chorea
Choria: flicking movements in the hands, face, or elsewhere
lesions in the striatum
Define the following and relate to respective lesions.
Parkinson’s
Parkinson’s: characterized by an overall inhibitory effect caused by the destruction of the dopaminergic neurons
(dopamine inhibits the indirect (inhibitory) pathway and excites the direct (excitatory) pathway)
lesions in the compacta of the substantia nigra
Define the following and relate to respective lesions.
Huntington’s
Huntington’s: An increase in motor activity caused by the inability to inhibit the indirect pathway
Lesions in the caudate circuit
Give an example of disinhibition that occurs in the following pathway.
Putamen Circuit Cerebral cortex (+acetylcholine) --> Putamen (-GABA) --> Globus Pallidus and Substantia Nigra (-GABA) --> Thalamic relay nuclei (+glutamate) --> Primary motor cortex
The -GABA on the Globus Pallidus and substantia nigra
this is basically a “negative stimulation to an already negative signal, making it a positive signal”
What is agnosia? With what lesion is it associated?
Agnosia: inability to accurately perceive objects through normally functioning sensory mechanisms
associated with lesions of the posterior parietal cortex
What are the most important functions of the basal nuclei (ganglia)?
Basal nuclei (ganglia): principle role is to work with the corticospinal system to modulate thalamic output to the motor cortex to plan and execute smooth movements
Compare the direct and indirect pathways of the basal nuclei (give the names of the circuit, increase/decrease in activity, function, and neurotransmitters it uses)
Direct pathway: Putamen circuit increases activity
Functions to suppress rigidity
Acetylcholine, GABA, and Glutamate
Indirect pathway: Caudate nucleus circuit decreases activity
Functions in motor planning
Acetylcholine, GABA, Glutamate
In the Basal nuclei, what is the role of the substantia nigra reticularis and what is the role of the substantia nigra compacta?
Substantia nigra reticularis: is more heavily populated with GABA neurons
substantia nigra compacta: The site of most of the dopaminergic neurons in the substantia nigra (and the brain as a whole)
Both of these areas play roles in conducting motor movements
In the Basal nuclei, what is the role of the subthalamic nuclei
The subthalamic nuclei serve to inhibit the contralateral side of movements
(basically tells one part of the body to chill if another part is going to be executing a movement)
Based on the following description, state the basal nuclei that is likely to have a lesion.
Inability to maintain postural support
Athetosis
(Continuous spontaneous writhing movements of a hand, arm, neck or face)
Globus Pallidus
Based on the following description, state the basal nuclei that is likely to have a lesion.
Release of inhibition on the contralateral side that leads to Hemiballismus
(sudden, flailing movements of an entire limb)
Subthalamic Nuclei
Based on the following description, state the basal nuclei that is likely to have a lesion.
Release of inhibition that leads to Chorea
(flicking movements in hands, face, or elsewhere)
Occurs in pt’s with Huntington’s disease
Striatum
Based on the following description, state the basal nuclei that is likely to have a lesion.
Caused by destruction of the dopaminergic neurons and occurs in pt’s with Parkinson’s disease
Results in rigidity, akinesia, and tremors.
Substantia Nigra
