Week 9B Flashcards
What nucleus within the basal ganglia contains dopaminergic
neurons? Where does this nucleus project to within the basal ganglia
Substantia nigra
projects to the striatum - dopamine transmission
projects to subthalmic nucleus - inhibitory neurotranmitter - back in neg feedback loop
Some antipsychotic medication used to treat schizophrenia works to inhibit dopamine transmission and can cause Parkinsonian-like
symptoms.
B) Explain how this type of antipsychotic medication may cause Parkinsonian-like symptoms within the context of the Basal Ganglia’s
direct pathway (diagram may be useful).
when dopamine transmission is inhibited striatum not excited and it can no longer inhibit GPI as much
GPI inhibits the thalamus more
thalamus decrease excitation onto motor cortex
decrease cortex activation of muscles = PD sumptoms
explain the path of parkinsons from the decrase in dopaine to PD symptoms - use diagram
when dopamine transmission is inhibited striatum not excited and it can no longer inhibit GPI as much
GPI inhibits the thalamus more
thalamus decrease excitation onto motor cortex
decrease cortex activation of muscles = PD sumptoms
where are 50% of our brains neurons located?
cerebellum
the cerebellum is referred to as out ____ because it ___
comparator compares intention vs what actually happeneed
does cerebullm receive afferent or efferent motor info
both!
what are three functions of the cerebellum?
balance and posture maintenance
coordination of voluntary movements
motor learning
The cerebellum coordinates the ___ and ___ of msucles to ensure ___ movments
timing and force ensure smooth movement - control voluntary movements
cerebellum is improtant for maintenance of ___ and ___
balance and posture
similar to cerebrum the cerebellumhas 2 ____ hemispheres
symmetric
what are the 4 symmetrical sections of the cerebellum?
- hemispher
- vermis
- intermediate zone
- floculondular lobe
what are the 3 pathways in the cerebellum?
spinocerebellar
cerebrocerebellar
vestibulocerebellar
where is the spinocerebellar path located ?
vermis and intermediate zones
what is the main role of the spinocerebellar pathway?
motor coordination - integrated sensory and motor info
where si the cerebrocerebellar path lcoaed?
lateral hemisphere
what input does the cerbeocerbellar pathway involve?
cortical
what is the main role of the cerebrocerebella pathway?
planning + timing of movements
where is the vestibulocerebellar path located?
floculonodular love
what are the 2 main rolse of the vestibulocerebellar pathway?
- posture and 2. vestibular reflexes
what input does the vestibulocerebellar pathway involve?
vestibular nuclei input
what two pathways in the cerebllum are important for smooth coordinated movements?
cerebrocerebellar pathway + spinocerebellar
what pathway within the cerebllum is responsibel for balance control?
vestibulocerebellar pathway
how do we know if there is dysfunction in the cerebellum
damge or loss of cerebellar tissue
what are 4 symptoms of cerrebellar dysfunction?
ataxia - lack of coordination, decomposition + jerky movement
dysmetria - inability to make accurate movements/overshooting undershooting
hypotonia - decrease in muscle tone/resistance
large amounts of sway
if someone overshoot when reaching for their class rpetty often where mgiht the issue be? what is this called
their cerebellum - dysmetria
what is efference?
motor command sent form motor cortex to body
what is teh efference copy?
copy of motor command - sued to update otehr brain regiosn on the acion about to. beperformed
Which of the following is an example of re-afference?
A) Self-generated motor command
B) Externally-generated motor command
C) Sensory information from self-generated movement
D) Sensory information from an external source
sensory info form self generated movement
ex affernce is from ___ source hile re-affernce is form ___. source
externally generated, unexpected vs reafference is self-generated + expected
corolary dsicharge represents the ____ we ____ from ___ movmement
re-affernce we EXPECT from self-genrated movement
what is corollary discharge used to inhibit
any self-generated mvoemnt taht may interfere with motor task
what is the first step of the feedforward moedl?
movement goal is sent to the motor cortex and an appropriate moror plan is selected base don previous experience
what 2 things happen in teh feedforward model after the movement ggoal is sent to mtor cortex
- efference (motor command_ sent to muscles in body to execute mtoor plan base don previous experienve
- efference copy is sent to the cerebellum to updat on wha tis about to happen
where is corollary discharge produced and what is it created from?
cerebellum - created form the efference copy
what does corollary discharge represent? what is it used for?
the expected sensory feedback form movement
Used to inhibit any resposne to self-generated movement tha tmay interfere with motor task
where is re-afference produced?
body
corollary discharge represents the ____ sensory feedback we get form the movmment while reafferencce represents the ____
corllary disachrge represents the EXPECTED
reaffernce represent the ACTUAL sensory feedback
reafference is in the ___ while corllary discharge is in the ___
body
cerebellum
what is compared in the cerebellum in the feedforward model
corollary discharge and re-afference
compares expected vs actual sensory info
what happens wh comparison of expected and acutal sensory info within the cerebllum match?
what if they dont?
the movement is excuted
If they don’t, unsuccessful execution - update motor cortex and and adjust motor plan
