L18: Basal Ganglia - B Flashcards
True or False: The CST is predominately made up of Primary Motor Cortex, however the Premotor Cortex and Supplementary Motor Cortex contribute to the CST
True
Which structure is responsible for executing a simple movement?
Which structure is responsible for complex motor responses (e.g planning motor task)?
Primary Motor Cortex = execute simple movement
Premotor Cortex = complex motor responses (planning motor task)
True or False: The Supplementary Motor Cortex coordinates movement on both sides, coordinates posture and voluntary movements
True
Involuntary movements and altered motor tone suggest damage to the ___ ____
basal ganglia
True or False: Basal Ganglia are composed of deep nuclei of telencephalon + diencephalon, as well as the midbrain
True
True or False: The Basal Ganglia is involved in coordinating and planning involuntary movements
False - voluntary movements!
Overall function of Basal Ganglia?
Smoothly orchestrate motor behavior and regulate AMPLITUDE of movement
Label the Corpus Striatum:
Globus Pallidus
Caudate Nucleus
Putamen
Which two structures make up the Striatum?
Which two structures make up the Lentiform Nucleus?
Which three structures make up the Corpus Striatum?
Where is the Substantia Nigra located?
Rostral midbrain
What does the cortico-basal ganglia-thalamo-cortical loop look like??
What are the Interconnections of the Basal Ganglia and which NT are utilized?
The basal ganglia sends feedback to the ___ upon request
cortex
What do red arrow indicate?
Indicate: always turned on, constitutively active, inhibitory neurons
What is the default of this pathway?
Inactivation of thalamus
No muscle movement
Information from the cortex to the striatum are known as Corticostriate Inputs. These inputs are excitatory and use ___ as a NT
Glutamate
What’s the difference between the Direct and Indirect Pathway?
Direct: FACILITATES flow of movement through thalamus; INCREASES thalamic/cortical activity/movements
Indirect: INHIBITS flow of information through thalamus via subthalamic nucleus; DECREASES thalamic/cortical activity/movement
Which pathway is this?
Which pathway is this?
Where are the spiny neurons located?
D1 is activated by ___ and inhibited by _____
A. GABA; Ach
B. Dopamine; GABA
C. Dopamine; Ach
D. Ach; GABA
C. Dopamine; Ach
D2 is activated by ___ and inhibited by ____
A. GABA; Ach
B. Dopamine; GABA
C. Dopamine; Ach
D. Ach; GABA
D. Ach; GABA
Which structure is responsible for releasing dopamine?
Which structure is responsible for releasing Ach?
DA = Substantia Nigra
Ach = Striatal Interneurons
In the direct pathway, the substantia nigra is activated, leading to release of dopamine.
This activates ___ receptor.
Pathway is enhanced, reverberating circuit is maintained…
D1 receptor
In the direct pathway, Striatum projects to the Substantia Nigra and inhibits which part of it (pars compacta or pars reticulata).
Which inhibitory NT is involved?
What is the ultimate effect of this?
Pars Reticulata; GABA
- Dopamine is released + excites D1 receptors
Which NT excites the direct pathway?
Dopamine
True or False: The net effect of dopamine is to increase motor activity and movement
True
Loss of dopamine and difficulty in making voluntary movements is associated with which medical condition?
Parkinson’s Disease
What is the cause of Parkinson’s Disease?
Loss of dopaminergic inputs to the striatum from the substantia nigra (pars compacta)
Which pathway is dominant in Parkinson’s Disease (and, therefore, leads to serious lack of movement)?
Indirect Pathway
Which neurotransmitter excites the indirect pathway?
Ach
True or False: Ach turns down motor activity and decreases movements
True
The cholinergic projections excite the ___ neurons of the indirect pathway, leading to further activation and decreased movement
Striatopallidal neurons
Loss of Ach results in…?
Abnormally increased movements
Which condition can arise due to loss of cholinergic interneurons in the striatum?
The dominance of which pathway leads to excess, unwanted, and uncontrollable movements?
Chorea; Direct Pathway
What are the two main functions of the basal ganglia?
True or False: The basal ganglia influences motor movements because they have direct connections to lower motor neurons
False - basal ganglia influences motor movements even though they have NO direct connections to LMN’s
True or False: The basal ganglia work with the ipsilateral cortex to influence movement of contralateral side of the body
True
Overview??
