11a: Basal Ganglia Flashcards
Which structure of the basal ganglia is the oldest?
Amygdala
The striatum are (X) structures interconnected. They’re also interconnected with which other structures? These are essential for proper functioning of:
X = caudate and putamen
- GP
- SN
- Subthalamic nuclei
Voluntary motor systems
The basal ganglia give rise to (X) descending tract(s), innervating LMN.
NONE
The basal ganglia give rise to (X) descending tract(s), innervating CN.
NONE
Which structure of basal ganglia is most recently developed?
Striatum (aka “neostriatum”)
Afferents to the striatum arise mainly from layer (X) neurons.
X = Layer 5
Prefrontal cortices terminate in (putamen/caudate).
Caudate
Temporal and parietal association areas terminate in (putamen/caudate).
Caudate
Motor cortices terminate in (putamen/caudate).
Putamen
Somatosensory cortices terminate in (putamen/caudate).
Putamen
(Caudate/putamen) sends inhibitory efferents to (external/internal) segments of GP. Which NT used at the synapse?
Both; Both
GABA
The pallidum is another name for:
GP
The “lentiform nucleus” is made up of:
Pallidum and putamen
GP external segment sends (excitatory/inhibitory) projections to (X). Which NT is used?
Inhibitory (GABA);
X = Subthalamic nucleus
GP internal segment sends (excitatory/inhibitory) projections to (X). Which NT is used?
Inhibitory (GABA);
X = VA/VL Thalamus
(X) structure as actually part of pallidum, but was separated by the cerebral peduncle. Like (external/internal) GP, it receives (excitatory/inhibitory) afferents from (Y) and sends (excitatory/inhibitory) efferents to (Z).
X = SN (pars reticulata)
Internal;
Inhibitory; Y = striatum
Inhibitory; Z = thalamus
The (internal/external) segment of pallidum sends efferents to thalamus via which white-matter tracts? Star the one that penetrates (X).
Internal;
X = internal capsule
- Lenticular fasciculus*
- Ansa lenticularis
Cerebellar input to (X) of thalamus, specifically from (Y) nucleus, (mirrors/contrasts) that of the pallidum.
X = VA/VL;
Y = dentate
Contrasts (is excitatory)
SNpc is (identical/different) from SNpr. It’s composed of (GABA/glutamin/dopamin)-ergic neurons. It receives (excitatory/inhibitory) in put from (X) and sends its efferents to (Y).
Different; Dopaminergic; Excitatory X = cerebral cortex; Y = striatum
Dopamine released by SN(pr/pc) has which effect on the targeted (X) structure?
SNpc;
X = striatum
- Excitatory if D1 receptor
- Inhibitory if D2 receptor
The subthalamic nucleus is located in the (telencephalon/diencephalon/midbrain) and is reciprocally connected with (X). It receives (excitatory/inhibitory) input from (X) and projects (excitatory/inhibitory) output to (Y).
Diencephalon; X = GP Inhibitory from external X = GP Excitatory; Y = internal GP
Overall, activation of subthalamic nucleus via (increase/decrease) GP(i/e) output has (excitatory/inhibitory) control over thalamus.
Decrease
GPe
Inhibitory (since subthalamic nucleus excites GP internal, which inhibits thalamus)
Overall, (activation/inhibition) of subthalamic nucleus via cortex has (excitatory/inhibitory) control over thalamus.
Activation;
Inhibitory (since subthalamic nucleus excites GP internal, which inhibits thalamus)
Overall, activation of subthalamic nucleus has (excitatory/inhibitory) control over cortex.
Inhibitory
List the components of the “direct path” of motor control via the basal ganglia. Put +/- following each component to indicate whether it’s sending excitatory/inhibitory efferents.
- Cortex (+)
- Striatum (-)
- GP/SNpr (-)
- VA/VL (+)
- Cortex
The “direct path” of motor control via basal ganglia has net (excitatory/inhibitory) effect.
Excitatory (on select motor programs)
List the components of the “indirect path” of motor control via the basal ganglia. Put +/- following each component to indicate whether it’s sending excitatory/inhibitory efferents.
- Cortex (+)
- Straitum (-)
- GP external (-)
- Subthalamic nucleus (+)
- GP internal (-)
- VA/VL (+)
- Cortex
The basal ganglia are located in (telen/dien/mesen)-cephalon.
Specific BG nuclei found in all three
List the key nuclei of the basal ganglia. Put “T”, “D”, or “M” next to each, depending on if it’s in telen/dien/mesen-cephalon.
- Striatum - Caudate, Putamen (T)
- Pallidum (T)
- Subthalamic nucleus (D)
- Substantia Nigra (M)
Direct pathway neurons in (X) structure have (D1/D2) dopamine receptors, which (hyper/de)-polarize the cell in response to dopamine.
X = striatum;
D1
Depolarize
Indirect pathway neurons in (X) structure have (D1/D2) dopamine receptors, which (hyper/de)-polarize the cell in response to dopamine.
X = striatum;
D2
Hyperpolarize
The nigrostriatal pathway, aka (X) sending efferent signals to (Y), has the dual effect of :
X = SNpc Y = striatum
- Exciting direct (stimulatory) pathway
- Inhibiting indirect (inhibitory) pathway
Excitation of the nigrostriatal pathway has the net effect of (exciting/inhibiting) cortex.
Exciting
Which pathway is compromised in Parkinson’s disease?
Nigrostriatal (SNpc to striatum)
Hemiballismus is caused by (unilateral/bilateral) destruction of (X). What does the condition present as?
Unilateral;
X = subthalamic nucleus;
Involuntary/irregular flinging of contralateral extremity
Huntington’s Disease is caused by early degeneration of (X). What does the condition present as?
X = striatum;
Involuntary, writhing movements
What are the three cardinal symptoms of Parkinson’s?
- Bradykinesia
- Rigidity
- Tremor
What are the symptoms of Dopamine excess in PD treatment?
- Dyskinesias (involuntary discoordinated movement)
- Dystonia (involuntary abnormal postures)
- Delusions/hallucinations/misperceptions
One FDA approved treatment for PD is (uni/bi)-lateral stimulation of (X) structure. This (raises/lowers) its firing rate.
Bilateral;
X = subthalamic nucleus;
Lowers (thus decreasing GPi activation)
