Ch. 11: Basil Ganglia, Cerebellum, and Movement Flashcards
What does the Basil Ganglia control?
- Subcortical
- Motor Control
- Motor Planning
- Motor Adjustment
“Predict the effects of various actions, then make and execute action plans”
In the Basil Ganglia, what is the Caudate and what does it do?
- Connects to frontal lobe - connective link to prefrontal cortex
- Helps decide what movement you want to make
In the Basil Ganglia, what is the Substantia Nigra and what does it do?
- Compacta: Creates Dopamine = critical neurotransmitter for Basil Ganglia to work
- Reticularis: output - helps control head and eye movement
What do the Basil Ganglia’s projections to the motor planning areas of the cerebral cortex do?
- Instructions to voluntary muscles on how you want to move
- Ex: Grab cup
- Output to motor planning areas of frontal lobe
What do the Basil Ganglia’s projections to Pedunculopontine do?
- Postural muscles so you dont’ fall over
- Mucleus of the midbrain - output to subcortical UMN’s (esp cor & prox muscles
What do the Basil Ganglia’s projections to the midbrain locomotor region do?
- Stepping pattern generator
In the Basil Ganglia what are the functions of the:
Motor Loop
*Output of Basil Ganglia is inhibatory*
- Sequencing of movements
- Regulating muscle tone
- Regulating muscle force
- Facilitating or inhibiting specific motor synergies
VERY important in motor learning - may be the spot where old skills are stored
In the Basil Ganglia what are the functions of the:
Oculomotor Loop
Helps with moving eyes to know where you are going
In the Basil Ganglia what are the functions of the:
Executive Loop
Connection to the prefrontal cortex - to executive areas
What are Hypokinetic Disorders and what is an example?
- Excessing inhibition from output nuclei
- Ex: Parkinson’s Disease
What is the pathophysiology of Parkinson’s Disease?
- Death of dopamine producing cells
- Lack of dopamine = inc inhibatory output from basil ganglia
- Further inhibits Motor Thalamus = DEC voluntary muscle control
- Further inhibits Pedunculopontine (inhibitor) = double negatives make a positive = OVERACITVE postural & girdle muscles
- Further inhibits Midbrain locomotr regioan = DEC walking control
What are the signs of Parkinson’s Disease?
- Akinesia/hypokinesia. Less voluntary movement (less lateralcorticospinal)
-
Rigidity (typically “cog wheel”) - more core and prox muscles = stiff on both sides of the joint
- NOT velocity dependent
-
Freezing during movement - Trouble with the motor plan
- Cant send sequence signals to lateralcorticospinal
- Visuoperceptive impairments - dec occulomotor loop
- Postural instability - stiff and slow activation
- Resting tremor - goes away with movement
What are Hyperkinetic Disorders and what is an example?
- Inadequate inhibition from output nuceli
- Ex: Huntington’s Disease
What is the pathophysiology of Huntington’s Disease?
- Degeneration of basal gangli “input modules” and cerebral cortex (not as much info = not as much inhibition out)
- Decreased inhibition to Motor Thalamus = OVERACITVE voluntary muscle control
- Decreased inhibition of Pedunculopontine (inhibitor) = = DECREASED postural & girdle muscles
- Decreased inhibition of Midbrain locomotor region = OVERACITVE walking
What are the signs of Huntington’s Disease?
- Chorea: involuntary extra movements that are typically twisting or writhing in nature
- Dementia: Atrophy of cerebral cortex
What is the Cereballum the organ of?
- Organ of coordination
- compeares what you meant to do to what’s actually happening and makes a change if needed.
What are the 2 inputs to the cereballar cortex?
- From brain to pons
- intended movements - “What I meant to do”
- Sensory receptors via spinal cord
- State of body system at the moment - “What I am really doing”
What are the 3 cortical layers of the cerebellum?
Computer of the cerebellum
- Outer - processing
- Middle - Purkinjie cells: output
- Sends inhibition like Basil Ganglia
- Modulates or fine tunes movements
- Inner - processing
What does the output of the cerebellar cortex do?
- Inhibitory
- Project to deep cerebellar nuclei and vestibular nuclei
What are the vertical divisions of the cerebellum and what do they control?
- Midline vermis - most prox muscles
- Paravermal hemisphere - slightly more distal muscles
- Lateral hemisphere - distal muscles (esp hands and feet)
What are the 3 function divisions of the cerebellum?
- Vestibulocerebellum
- Spinocerebellum
- Cerebrocerebellum
What does the Vestibulocerebellum do?
*Handlebar mustache connected with inner ear*
- Balance and equilibruim - hold you upright against gravity
- ”..influences eye movemetn and postural muscles..”
- esp vestibulospinal tract (ext legs to keep you balanced)
What does the Spinocerebellum do?
*Midline of cerebellum - functionally linked with the spinal cord (esp core & prox muscles)
- Gross movements of the limbs
- generate activity to medial corticospinal & brainstem
- Control ongoing movement via the brainstem descending tracts
- facilitates directors & helpers of core & prox muscles
- Receives rich “what am I doing now” info
- Automatic corrections
- New movement plans (ex: like when falling)
What does the Cerebrocerebellum do?
*Strongest connection with cerebral cortex*
- Fine, distal, voluntary movements - esp hands & feet
- Soordination of voluntary movments
- Planning of movemnts - works with basil ganglia
- Ability to judge time intervals and produce accurate rhythms
- Output to lateral tracts
- Rednucleus helper
- Motor cortes - esp lateral corticospinal tract
What does the superior cerebellar peduncle do?
- Most of cerebellar efferent - output of cerebellum
- Wires that take messages out of cerebellum
- Messages of unconscious (to helpers) and conscious (to directors) correction
What does the Middle cerebellar peduncle do?
- Afferent from corticopontocerebellar fibers
- In line with pons
- Afferent from porticopontocerebellar (xerox copy)
What does the Inferior cerebellar peduncle do?
- Afferent from spinal cord and brainstem
- Closest to spinal cord
- Messages of what I am really doing
What are the functions of the cerebellum?
- Comparing actual motor output to the intended movement.
- Adjusting actual motor output if there is a discrepancy.
What are sings of Clinical DIsorders of the Cerebellum?
- Hypotonia
- Ataxia: movements are erky & inaccurate
- lack of coordination
- Signs are ipsilateral to side of damage
What signs are associated with lesions of the Vestibulocerebellum?
-
Abnormal eye movements
- Eyes may not move properly during movement
-
Dysequilibrium
- Out of balance
-
Truncal ataxia
- Trunk does not stay stable - makes coordinated movement difficult
What signs are associated with lesions of the Paravermis & Cerebrocerebellum?
- Dysarthria
- Difficulty/disordered mechanical production of speech.
-
Ataxic Dysarthria: Changes rate, pitch, annunciation (specific to cerebellar damage)
- Sound drunk
What signs are associated with lesions of the Spinocerebellum?
- Ataxic, wide-based gait
- Mechanically more protected against falls
What signs are associated with lesions of the Spinocerebellum & Cerebrocerebellum?
-
Dysdiadokokinesia: Disordered alternating movement
- Cerebellum having trouble gaging timing and rhythm of movement
- Dysmetria: Inability to accurately hit a target
- Action or intension tremor: Only tremor with movement
How do distinguish between Cerebellar Ataxia and Sensory Ataxia?
