OT 6000 Test 4 Flashcards
Cerebellum- pontocerebellar
Portion of cerebellum that knows what was intended to do for action
Cerebellum- Spinocerebellar
Portion of cerebellum (along with vestibular portion) that knows what actions you are actually doing
Cerebellum- brainstem and motor cortex
Make corrections in action to match what was meant to do and what was actually done
Gray matter of cerebellum
Gray matter outside of the cerebellum is packed with cell bodies and is responsible for comparing what body is doing to what was actually done
Cerebellar inputs
- *What I am doing
1. Spinal cord: discriminitive touch
2. Reticular formation: what is the urgency of the movement?
3. Vestibular system: inner ear shows head movement and the pull of gravity - *What I meant to do
4. Pontine nuclei: xerox copy coming from cerebral cortex down pons and into the cerebellum
Cerebellar outputs
- Purkinje cell: takes the result of the processing down to the base of the cerebellum and passes signal to cerebellar nuclei
- Cerebellar nuclei: takes signal to brainstem for gross motor UMN’s and to the cerebral cortex for fine motor UMN’s
Vertical divisions of the cerebellum
- Midline vermis: anitomical midline that controls to midline axial skeleton
- Paravermal hemisphere: controls the most proximal joints (shoulders and hips)
- Lateral hemisphere: controls the distal muscles
Flocculonodular lobe
Lobe of the cerebellum that helps maintain equilibrium
Cerebellar Peduncles (inferior, middle and superior)
- Inferior: brings messages of what I’m actually doing to the cerebellum (input from SC and brainstem)
- Middle: brings in the xerox copy of what was meant to be done (input from the pontine nuclei)
- Superior: Takes messages up to the cerebellum to makes corrections if needed (output to brainstem and cerebral cortex)
Functional Divisions of the Cerebellum:
Spinocerebellum division:
Vermis and paravermis- core and proximal muscle control (braimstem connection= low voluntary control)
- Input: spinocerebellar tracts (discriminitive touch and non-conscious proprioception- “what I am actually doing”) and sensorimotor cortex (compares what you meant to do with what you did)
- Output: Medial division UMN’s of cerebral cortex and brainstem (ipsilaterally)
Functional Divisions of the Cerebellum: Vestibulocerebellum division
Flocculonodular lobe- balance and equilibrium
- input: inner ears
- output: vestibular nuclei> eye muscles (steady gaze for balance) and postural muscles (keep you upright)
Functional Divisions of the Cerebellum: Cerebrocerebellum division
Lateral hemispheres- fine motor control (cortex connection= high voluntary control)
- Input: cerebral cortex
- Output: lateral division UMN
- **passes on the “xerox copy” of movement plan to coordinated movement and timing
Signs of damage in the cerebellum
- Signs are always ipsilateral (same side as damage)
- Often include Ataxia (incoordination due to muscle weakness)
Vermal and floculonodular damage
Leads to truncal ataxia- issues controlling the trunk of body
Spinocerebellar damage
Leads to gait ataxia-issues controlling the lower trunk directly over hips (wide-base unsteady and staggering).
-runs to spinocerebellum; damage here also leads to limb ataxia: intentional action tremor, dysmetria (impaired ability to hit target) and dysdiadochokinesia (issues with rapid, alternating, reversing movements around joint)
Cerebrocerebellar damage
Leads to hand ataxia: issues coordinating fine motor movement in hands
Vestibulocerebellum damage
Leads to nystagmus: eye movement problems leading to balance deficits (truncal ataxia) and equilibrium issues
Paravermis and hemisphere damage
Leads to dysarthria: disordered production of speech ( speech varies in pitch, volume and rate like a drunk person)
Cerebellar vs. Somatosensory Ataxia
- Cerebellar ataxia: Cerebellum cannot compare and correct information on planned movement
- ->issues with coordination- eyes open or closed, but will have normal sensation of touch
- Somatosensory ataxia: information never reaches cerebellum to communicate “what you are really doing.”
- ->pt with this ataxia will be able to substitute sensory info with visual info- as long as eyes open, balance stays. However; there will be no normal sensation of touch
Basal ganglia overview
The “control circuit”- sends output to the cortical UMN’s and the brainstem UMN’s
-This helps plan movement in the cortex of “what I meant to do” compared to “what I want to do”
Motor influence of the basal ganglia
- Influences the cortical UMN’s via the thalamus (BG influence is inhibitory, thalamus’ is excitatory)
- ->voluntary movement
- Influences the brainstem via the pedunculopontine nucleus (inhibitory) AND via the midbrain locomotor region (influence becomes excitatory after the locomotor)
- ->Pedunculopontine “inhibits the inhibitor”- inhibits the reticulospinal tracts that are the postural muscle inhibitors
- ->Locomotor region is the stepping pattern generator
Components of the basal ganglia
- Substantia nigra: most important component- has the cells which create dopamine, which runs the internal communication and processing in the BG (adjusts and/or inhibits output from BG)
- Caudate: “what I want to do”
- Putamen- “what I am doing”
- Globus pallidus- based on info, what is my movement plan
Basal ganglia input and output
- Input is always excitatory: Glutamate, Acetylcholine and Serotonin
- Output is ALWAYS INHIBITORY: either inacts GABA or runs it off
Goal-directed behavior loop of basal ganglia
Executive functioning: evaluating information for making decisions, planning, choosing actions in context and learning
-found roughly on hairline
Emotional loop of basal ganglia
Emotions and motivations that lead to motor plan, reward seeking, making predictions of outcomes and integrating emotions with facial expressions
- found roughly on forehead
- damage here leads to impulsive patients
Social behavior loop of basal ganglia
Recognizing social cues, regulating self-control, and distinguishes relevant from irrelevant information
- found roughly behind eyebrows
- damage here will lead to someone not understanding social boundaries or socially acceptable behavior
Oculomotor loop of basal ganglia
Decisions about spatial attention and eye movement and directs eye muscles to “look at” something
-Found roughly on top of head
Motor loop of the basal ganglia
Regulates muscle contractions, force of contractions, order of muscle contractions and multi-joint movements (all needed for muscle synergy)
Basal ganglia’s role when initiating plan of movement
- Suppresses any ongoing motor programs
- Facilitates appropriate muscles to move in the way you want
- Inhibits muscles that produce unwanted or unnecessary movement
Parkinson’s disease in relation to basal ganglia
- Parkinson’s (a hypokinetic disorder) causes the death of dopamine producing cells in the substantia nigra
- This death leads to an increase of basal ganglia output, causing:
1. Too little activation of voluntary muscles
2. Too much activation of postural and girdle muscles (stiff posture)
3. Too little activation of locomotor region (stepping pattern generator)
Huntington’s Disease in relation to basal ganglia
- Huntington’s disease is a hyperkinetic disorder which cause the degeneration of basal ganglia and cerebral cortex
- Dopamine is available but the input into the basal ganglia has diminished, which causes a DIMINISH in basal ganglia output
- ->this leads to too much activation of voluntary muscles and too little activation of postural and girdle muscles (choreaform, or writhing/twisting, movement is the norm)
Feedforward vs Feedback control of balance
- Freeforward: I anticipate the loss of balance and prepare in such a way that I don’t lose it
- Feedback: recovering after something has knocked you off balance
Rami classification
- Anterior Rami: all axons that feed arms, legs and front of body
- Posterior Rami: all axons that feed the back
- Communicating Rami: take autonomic neurons too and from peripheral synapse
Plexus damage
All plexuses are distal to spinal nerves and proximal to peripheral nerves
-Any damage done to a plexus will be peripheral in nature
Spinal nerve vs peripheral nerve damage
- Damage to one spinal nerve: dermatome pattern of sensation loss (one whole dermatone sensation is lost) and myotomal pattern of motor loss (many muscles weak but not paralyzed)
- -> example: bulging disc
- Damage to one peripheral nerve: peripheral pattern of sensory loss (will lose some but not all of dermatome sensation) and peripheral nerve pattern of motor loss (small number of muscles paralyzed)
- ->example: tunel of Guyon
Peripheral nerve bundles
- Endometrium surrounds individual axon
- Perineurium surrounds bundles of axons (makes a fascicle)
- Epineurium surrounds bundles of fascicles
Axons of peripheral nerves
- A-alpha: efferent- extrafusal muscles
- Ia, Ib, II: afferent- proprioception
- A-beta: afferent- exteroception
- A-gamma: efferent- intrafusal muscles
- A-delta: afferent- pain, temp, viscera
- B: efferent- presynaptic autonomic
- C: afferent- pain, temp, visera (dull aching pain)
- C: efferent- postsynaptic autonomic (sharp pain)
Plexuses
- Cervical= C1-C4
- Brachial= C5-T1
- Lumbar= L1-L4
- Sacral= L4-S4 (only plexus containing CNS AND PNS axons)
- *One PN gets input from many different spinal levels, one spinal level branches out to many different peripheral nerves
How movement improves nerve health
- Improves blood flow
- Facilitates gliding of nerves and fascicles
- Facilitates antereograde and retrograde axoplasmic transport
- Lack of movement leads to physical stress on neural membrane (Nn get stuck on connective tissue)
Neuropathy classification by number of sick Nn
- Mononeurophathy- one sick nerve. Example: unilateral carpal tunnel
- Multiple mononeuropathy- several sick Nn. Example: bilateral carpal tunnel
- Polyneuropathy- many sick Nn. Example: glove sensation loss of fingers, hands and wrists