Function of Cerebellum-Basal Ganglia 2 Flashcards Preview

Neuro exam 3 > Function of Cerebellum-Basal Ganglia 2 > Flashcards

Flashcards in Function of Cerebellum-Basal Ganglia 2 Deck (26)
Loading flashcards...
1
Q
How do dopaminergic neurons recognize reward prediction errors:
A
1. striosome conveys current predictions about – reflect present state of cortico-striatal network to these neurons
2. Additional inputs to the SNc/VTA convey info about actual reward experience.
3. ACTS AS A COMPARATOR – activated by mismatch between observed and expected rewards
2
Q
The mu-opioid receptor is located:
A
throughout the striatum (of basal ganglia) except for in certain patches.
3
Q
patches where the mu-opiod receptors are missing are the
A
striosome

with medium spiny GABAergic neurons who project through direct pathways to the SNc/VTA dopaminergic neurons.
4
Q
how do dopaminergic neurons in the VTA/SNc acts as a comparator
A
1. unexpected reward will strongly activate neurons
2. dopamine releases into striatum to alter the activity and PLASTICITY of cortico-striatal networks.
3. Networks that correctly predicted the error will be reinforced and those that do not correctly predict the error will be diminished
5
Q
Cerebellar pathways connecting parietal and premotor corticies effect a re-calibration so that if the visual coordinations (like adding a prism) and a given set of joint angles are different, ____
A
the brain can adapt for this. ONLY PERIOD OF ADAPTATION DEPENDS ON CEREBELLUM!!!
6
Q
Cerebro-cerebellum’s mossy fibers arise from___
A
contralateral pontine grey
7
Q
Mossy fibers are innervated by
A
cortico-pontine fibers descending through internal capsule.
8
Q
_____ contributes these cortico-pontine fibers that synapse on ponto-cerebellar neurons.
A
Parietal cortex
9
Q
Mossy fiber input =
A
reflection of present state of parietal cortical mapping between visual + proprioceptive signals.
10
Q
mossy fibers form synapses on
A
granule cells
11
Q
granule cells form synapses on
A
purkinje cells
12
Q
purkinje cells output is to the
A
dentate nucleus-->
thalamus-->
motor and premotor cortex
13
Q
ION sends climbing fibers to
A
purkinje cells
14
Q
The simultaneous discharge of olivary climbing fibers and parallel fibers leads to
A
changes in synaptic strengths of parallel-purkinje synapses, which can reconfigure the network.
15
Q
Comparator
A
compares the expected state with the observed state
16
Q
Expected state:
A
conveyed by deep cerebellar nuclei as a reflection of parietal network
17
Q
Observed state
A
conveyed by visual and proprioceptive feedback
18
Q
The ION acts as a
A
comparator
19
Q
The ION receives feedback about
A
proprioception and visual feedback
20
Q
The ION has
_____ neurons
A
GABAergic neurons
21
Q
The major input to the ION
A
from deep cerebellar nuclei

1. multiple sensory modalities which are different based on the subregion of ION they go to
2. These subregions project to different functional zones of the cerebellum
22
Q
ION, if the feedback is different than the expected:
A
the error signal is generated by ION
23
Q
Error signal is conveyed by
A
climbing fibers to cerebellar cortex.
24
Q
In the cerebellar cortex, the error signal:
A
initiates complex spikes in purkinje cells

The parallel fiber synapses on purkinje cells
25
Q
Long Term Depression:
A
1. change in synaptic plasticity of these parallel fiber synapses on purkinje cells.
2. Inverted form of longterm potentiation.
3. Simultaneous activity of the parallel fiber and climbing fiber leads to a decreases in parallel fiber’s efficacy in firing of Purkinje cell.
26
Q
Result of ION error signal
A
change in ensemble of active purkinje cells so that the ensemble that was active in erroneous movement has been deactivated and new ensemble conveys a revised reflection of parietal cortex’s mapping of visual and proprioceptive coordinates to the motor cortices.