Motor System 3

which cortical areas are involved in voluntary movement?

- posterior parietal cortex

- prefrontal cortex

- premotor and supplementary motor areas (SMA)

- primary motor cortex

direct (pyramidal) pathway

- UMN to brainstem and spinal cord to control gross motor movements

indirect (extrapyramidal) pathway

- refine and modulate movements initiated by the direct motor system

both _____ and ______ are involved in voluntary movement

- direct pathways

- indirect pathways

function of cerebellum

- coordination of movement / maintain balance

- regulates muscle tone

- motor learning (comparison of intent and action, automation)

- non-motor functions

comparison of intent and action (part of motor learning)

- comparing what you want to do and the result, then adjusting to fix

- ex. learning a new skill

automation (part of motor learning)

- once you learn a new skill, it eventually becomes automatic

ataxia dysarthria

- slurred speech

- sounds drunk

what is the basal ganglia

- group of subcortical nuclei

- NOT one single structure

parts of the basal ganglia

- caudate nucleus

- putamen

- globus pallidus

- substantia nigra

- subthalamic nuclei

basal ganglia circuits involve...

- regulating motor functioning

- cognitive planning

- affective control

basal ganglia: regulating motor functioning

- modulates the activity of the UPM

- activates, sustains, and inhibits movements

- coordinates motor behavior (multitasking)

- uses dopamine to regulate motor actions

activating movement

- motor cortex plays a bigger role in activating movements, basal ganglia just helps/supports

inhibition (basal ganglia regulating motor functioning)

- the skill we have to remove distractions

- ex. trying not to eavesdrop

basal ganglia: cognitive planning

- prefrontal inputs from basal ganglia associated with working memory

basal ganglia: affective control

- aka limbic system

- controlling emotions / emotional regulation

do lesions in the basal ganglia cause paralysis?

- no because we still have the motor cortex

- we would see discoordinated movements instead

dopamine in the _______ and _______ is required for motor control

- substantia nigra

- striatum

release of _______ controls / modulates movement

- dopamine

hypokinetic disorder

- not enough movement

hyperkinetic disorder

- too much movement

Parkinson's Disease (PD)

- movement disorder

- progressive neurological disorder

- 2nd most common neurodegenerative disease

how is PD diagnosed?

- from signs/symptoms

- can receive a PET scan

- if medication given works (increases dopamine), then you have it

early diagnosis of PD can be _____

- challenging

what can a patient do with PD early on to help maintain ADLs

- exercise

motor symptoms of PD

- resting tremors (shaky hands)

- increased muscle tone

- slow movement

- reduced range of motion

- difficulty initiating voluntary movement

- postural instability

- depression and cognitive deficits

- motor blocks: fixed posture and freezing

- speech/voice disorders

rigidity

- stiff muscles

bradykinesia

- slow movement

hypokinesia

- reduced range of motion

akinesia

- difficulty starting the movement

postural instability

- can become unstable and this means high risk for falls

depression and cognitive deficits

- due to lesion in circuit of basal ganglia and nervous system

motor blocks

- freezing mid movement

- ex. walking and all of a sudden cannot move

- very dangerous, lots of pts fall due to this

hypokinetic dysarthria

- soft spoken and as PD becomes worse, speech become more unclear

why can't vocal folds abduct all the way in patients with PD?

- rigidity and hypokinesia

what happens in the substantia nigra in patients with PD?

- neurons degenerate, die, and stop functioning properly

- dopamine is not produced

lewy body neurons

- survival of neurons but do not function properly

- seen in PD

dementia and PD

- later on in diagnosis, patients will develop dementia

- different from Alzheimer's kind of dementia

loss of dopamine results in ______ _______ in the _____ ________

- decreased excitation

- motor cortex

explain why the loss of dopamine results in decreased excitation in the motor cortex

- basal ganglia is not working properly which leads to reduced movement of patients in PD

- Reduced dopamine leads to reduced excitation of the motor cortex that leads to slow movement of reduced ROM

non-motor symptoms of PD

- cognitive impairment

- depression

- dementia

- speech changes / communication difficulties

- loss of smell in some

symptoms of huntington's disease

- hyperkinesia

- chorea

- dyskinesia

- emotional changes of cognitive disorder

- hyperkinetic dysarthria

- dysphasia

- dementia

hyperkinesia

- excessive, involuntary, unwanted movements

chorea

- dance-like movements

dyskinesia

- impairment of voluntary movement

what is the hallmark feature of huntington's disease and PD

- hyperkinetic movement for huntington's disease

- hypokinetic movement for PD

age of onset for huntington's disease

- 35

how many years after being diagnosed does someone with huntington's disease have to live

- 25 years after diagnosis

common way for someone to pass from huntington's disease

- pneumonia

- hard to eat and drink, causing aspiration, leading to pneumonia then death

etiology of huntington's disease

- genetic causes, runs in the family

what happens in the brain of someone with huntington's disease

- loss of neurons in the basal ganglia and cerebral cortex

- cortical degeneration, leads to changes in their function and behavior