Task 2 Flashcards
What do we call the kind of inhibition the Basal Ganglia has on the Cortex?
Tonic Inhibition
Activation of the Striatum leads to:
- activation of the cortex
- inhibition of the cortex
- disinhibition of the cortex
Inhibition of the cortex
The Caudate and the Putamen together form the:
Striatum
Describe the direct output pathway of the Basal Ganglia.
Striatum -> Substantia Nigra (r)/GPi -> Thalamus -> Cortex
Describe the indirect pathway of the basal ganglia.
Striatum -> Globus Pallidus externus -> Subthalamic Nucleus -> GPi/Substantia Nigra (r) -> Thalamus -> Cortex
Choose inhibits or excites:
The Globus Pallidus constantly ___ the thalamus. The Subthalamic Nucleus ____ the Globus Pallidus, thus preventing unwanted movements from happening. The Direct Pathway ____ the Substantia Nigra directly.
Inhibits, Excites, Inhibits
There are two types of dopamine receptors in the Basal Ganglia. Which type is present in which pathway?
D1 -> Direct Pathway
D2 -> Indirect Pathway
Which of the two dopamine receptors of the Basal Ganglia is inhibitory?
D2
What are two well-known diseases of the Basal Ganglia?
Huntington’s and Parkinson’s
Huntingtons is part of the class of ___ disorders.
Neurodegenerative
Huntingtons results in hyperkinesia and chorea. What does this mean?
Hyperkinesia = Excessive Movements Chorea = Involuntary Movements
What is the biological basis of Huntingtons?
Atrophy in the Striatum, which leads to disinhibition of the thalamus and thus the cortex.
Next to anomalies in posture, Parkinsons also leads to Hypokinesia and Bradykinesia. What does this mean?
Hypokinesia = Reduced voluntary movements Bradykinesia = Slowness of movements
What happens biologically in the brain of a Parkinsons patient?
Atrophy of dopaminergic neurons in the SNc
Why do reflexes and spasticity gain control after damage to upper motor neurons?
Spasticity is an over-contraction of muscles in reflexes counteracting gravity, which are no longer controlled by the cortical signals.
What is a limitation of using Deep Brain Stimulation as a treatment for Parkinson or Huntingtons?
For one location and one intensity/frequency setting, the stimulator in the brain has different effects on the different loops in the brain, leading to unwanted effects.
On what kind of genetic abnormality is Huntington based?
A repetition of a CAG sequence
What are three non-motor loops that the Basal Ganglia are involved in?
Parallel Loops
Dorsolateral Prefrontal Loop
Limbic Loop
What is the function of the Dorsolateral Prefrontal Loop and the brain parts involved in it?
- Involved in initiation of cognitive processes
- Dorsolateral PFC -> Anterior Caudate -> GPi -> Mediodorsal and ventral anterior thalamic nuclei -> Cortex
The Cortical loops of the basal ganglia all go though different parts of which subcortical structures?
Striatum, Globus Pallidus, Thalamus
What sequence does the limbic loop go through?
Limbic Lobe -> Ventral Striatum -> Ventral Pallidum -> Mediodorsal Thalamic Nucleus
