Flashcards in Basal Ganglia Intro Deck (45)
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1
Mvmnt disorders are a class of neurological disorders all related to ____ dysfxn. The resulting disorders are classified as either ____ or ____.
BG dysfxn
hypokinetic or hyperkinetic
2
Hypokinetic movement disorders include:
PD
parkinson's plus syndromes
3
Hyperkinetic movement disorders include:
chorea
athetosis
ballism
dystonia
4
Mvmnt disorders used to be called _______; still may see this term in reference to clinical signs of BG dysfxn.
extrapyramidal
(C-S = pyramidal)
5
What are the 2 primary roles of the BG?
1. initiate internally generated mvmnts
2. "sensorimotor agility": shift or change motor set as task demand changes
6
BG refers to the _______ including caudate, putamen, and globes pallidus.
subcortical grey matter
7
The lenticular nucleus consists of the:
Putamen
Globus pallidus internus
Globus pallidus externus
8
The striatum includes:
nucleus accumbens
caudate nucleus
putamen
9
The STN is located in the:
diencephalon
10
The sustantia nigra is located in the _____ and consists of these two parts:
midbrain
pars compacta (SNc)
pars reticulata (SNr)
11
Nucleus accumbens is the ____ part of the striatum, related to the ______ system.
ventral
limbic
12
What area is the "receiving" area of the BG?
striatum
receives inputs from all areas of cortex and thalamus
13
What areas use GABA (-) as neurotransmitter?
Striatum
Globus Pallidus
SNr
14
Describe the development of the striatum:
caudate and putamen are from same embryological origin
As caudate develops it grows around in wall of lateral ventricle
Putamen forms OUTER part of lentiform nucleus
15
What anatomic area forms the medial portion of the lentiform nucleus?
Globus pallidus (GPi and GPe)
16
What influence does GP on it's target?
inhibitory effect on THALAMUS
17
Which anatomical areas are considered the "outflow" nuclei of the BG?
1. GP
2. SNr
18
What influence does SNr have on targets?
inhibitory effect on THALAMUS and BS areas
19
Where is STN located?
ventral to thalamus, medial to internal capsule (in diencephalon)
20
What neurotransmitter does STN use?
glutamate (+)
21
What role does STN have?
involved in indirect circuit
22
SNc location vs. SNr?
SNc: dorsal part of SN
SNr: ventral part of SN; adjacent to crus cerebri
23
The neurons in the ______ contain the pigment neuromelanin, which gives SN its name.
SNc
24
SNc neurotransmitter:
dopamine (+)
25
SNc projects to the ____ and sets the background level of excitability.
striatum
26
Describe the net effect of the direct circuit:
thalamic and cortical excitation
(activation of motor program)
27
Describe the net effect of the indirect circuit:
thalamic and cortical inhibition
(inhibits unwanted or competing motor programs)
28
At rest, there is no mvmnt because the ____ projects inhibitory influence over the thalamus.
GPi
29
During mvmnt, direct circuit summary pathway:
Cortex +> Striatum -> GPi x> Thalamus / Cortex
30
During mvmnt, indirect circuit summary pathway:
Cortex +> Striatum -> GPe x> STN +> GPI -> Thalamus / Cortex
31
The functional combined effect of indirect and direct circuits:
related to the role of the BG in activating a desired motor program (direct circuit) while inhibiting a competing program (indirect).
32
The hyperdirect pathway is directly from _____ to _____ to directly inhibit unwanted program (inhibits thalamus).
cortex to STN
33
Dopamine comes from the ___ ;
There are __ different types of dopamine receptors.
SNc
5
34
Dopamine fxn and influence of lower levels of dopamine:
sets tonic background level of excitation on the thalamus
lower levels of activation in thalamic targets
35
Too little dopamine results in:
Too much dopamine results in:
too little: akinesia
too much: dyskinesia
36
Dopamine may act to focus attention by interacting with:
striatal neurons
37
What is the 2 roles of dopamine in motor learning and adaptive plasticity?
1. BURST COUPLES
2. LTP = Long Term Potentiation of cortical inputs
38
Describe BURST COUPLES:
interact with cortical input to striatal neurons during learning
39
Describe LTP of cortical inputs:
persistent increase in synaptic strength following high frequency stimulation of synapses... major role in implicit/procedural learning
40
The SNr affects brainstem systems for:
locomotion
muscle tone
eye mvmnts
41
Describe the locomotion function of the SNr (region, fxn):
mesencephalic locomotor region (MLR)
recruit CPGs in SC for locomotion
MLR affect rhythmic stepping, initiation, termination of motion
42
Describe the muscle tone function of the SNr (region, fxn):
reticular formation
projects to area of RF that controls muscle tone
without normal BG influence, muscle tone inc. (rigidity)
43
Describe the eye movmnt function of the SNr (region, fxn):
superior colliculus
generates saccadic eye mvmtns
44
What are the roles of BG in motor control?
1. generate internally triggered mvmnt
2. esp. active in overlearned mvmnts
3. flexible motor set selection and shifting
4. "gate" for processing sensory info / select relevant and suppress irrelevant / ongoing eval of environmental cues
5. cognitive-related fxns
45
