Neuro Mod 6 Flashcards
General functions of the cerebellum?
Maintain balance, maintain muscle tone/posture, coordinated movements (corrective forward/backward roles), motor learning/cognitive motor role
Cerebellum plays a major role in motor function but does not initiate what?
Motor commands
Cerebellum holds ___% of the brain’s volume and contains ___% of the neurons in the brain
10% volume, 50% of the neurons
“little brain”
Pathway of motor planning/learning in the cerebellum?
Anterior association area –> premotor cortices –> pons –> cerebellum –> thalamus –> premotor/primary motor cortices
Equilibrium is the ability to maintain what?
Balance
Which nuclei in the brainstem play a primary central role in maintaining equilibrium? Which other structure plays a role in equilibrium?
Vestibular nuclei in brainstem, also cerebellum
Where is the cerebellum located in the skull?
Posterior fossa
How is the cerebellum physically attached to the brainstem?
by cerebellar peduncles (incoming/outgoing axons arranged in 3 bundles of white matter)
The cerebellum forms the “roof” of what structure?
Fourth ventricle
Structures/landmarks of the brainstem?
Midbrain, pons, medulla
Which structure serves as the dural roof that separates the cerebellum and the occipital lobe?
Tentorium cerebelli
The fourth ventricle is a CSF cavity located _____ to the ____
Posterior to the pons
What structure is a CSF pathway/conduit that connects the third and fourth ventricles?
Cerebral aqueduct
What is the vermis?
Midline region of cerebellum
Which cerebellar hemispheres make up the medial portion?
Intermediate hemispheres (paravermis)
Which cerebellar hemispheres make up the large outer portion?
Lateral hemispheres
Which lobe is horizontal and located in the anterior region of the cerebellum?
Flocculonodular lobe
The flocculonodular lobe is the ______ part of the cerebellum?
“oldest”
Do cerebellar peduncles transmit info (to) or (from) the cerebellum?
Both two and from
What are the 3 cerebellar peduncles?
Superior, middle, inferior
How many pairs of deep cerebellar nuclei are located within the cerebellum?
Three (fastigial, interposed, dentate)
The fastigial deep cerebellar nuclei are associated with which pathways?
Vermis pathways
The interposed deep cerebellar nuclei are associated with which pathways?
Paravermis pathways
The dentate deep cerebellar nuclei are associated with which pathway?
Lateral hemisphere pathways
Which two nuclei form the interposed deep cerebellar nuclei?
Emboliform & globose
How does information travel in the lobes of the cerebellum?
Outgoing info leaving vermis, paravermis, and lateral hemispheres goes through deep cerebellar nuclei
Which artery supplies the anterior/superior cerebellum?
Superior cerebellar artery (SCA) - branch of superior basilar artery
Which artery supplies the anterior/middle cerebellum?
Anterior inferior cerebellar artery (AICA) - inferior basilar artery portion
Which artery supplies the posterior/inferior cerebellum?
Posterior inferior cerebellar artery (PICA) - branch of vertebral artery
Motor functions of the cerebellum?
Balance/vestibulo-ocular control, Trunk/proximal limb coordination, Distal limb coordination/fine motor movement, Coordination of motor planning for complex movement/learning
What motor function is controlled by the flocculonodular lobe?
Balance & Vestibulo-ocular control (coordinated eye movement: smooth pursuit, saccades, VOR, etc)
What motor function is controlled by the vermis?
Trunk & Proximal limb coordination
What motor function is controlled by the paravermis (intermediate hemisphere)?
Distal limb coordination/fine motor movement
What motor function is controlled by the lateral hemisphere?
Coordination of motor planning for complex movement/learning
Pathway/connections of the flocculonodular lobe?
Input from vestibular nerve (CN8) –> output through vestibular nuclei in brainstem
During flocculonodular lobe output, vestibular nuclei have some “upward” projection to control what?
eye movements via MLF
During flocculonodular lobe output, vestibular nuclei have some “downward” projection to control what?
balance/equilibrium
What are smooth pursuits (eye movement)?
Slow/smooth eye movement to maintain gaze on moving target (vertical or horizontal)
*head remains still
What are saccades (eye movement)?
Rapid eye movement from one target to another (vertical or horizontal)
*head remains still
The vermis pathways/connections receive input from what?
Spinocerebellar tracts (unconscious propioreception) from the trunk/proximal limbs, and vestibular nuclei (visual info)
The vermis pathways/connections travel through which deep cerebellar nuclei?
Fastigial nuclei
The vermis pathways/connections have output through what?
info travels to vestibular nuclei –> down medial motor tracts of the spinal cord (responsible for trunk/proximal muscles)
The paravermis pathways/connections receive input from what?
Spinocerebellar tracts (unconscious propioreception) from limbs, and motor cortex via pontine nuclei
The paravermis pathways/connections travel through which deep cerebellar nuclei?
Interposed nuclei
The paravermis pathways/connections have output through what?
Red nucleus (influences distal extremities via rubrospinal tract), and sends fibers to thalamus & motor cortex (influences distal extremities vie lateral motor tracts of spinal cord that control distal limb movement)
The lateral hemisphere pathways/connections receive input from what?
Motor associated cortex via pontine nuclei
The lateral hemisphere pathways/connections travel through which deep cerebellar nuclei?
Dentate nuclei
The lateral hemisphere pathways/connections have output through what?
Thalamus/cortex (info allows planning/learning complex movement in motor & somatosensory cortices), and Red nucleus (influences lateral motor tracts to assist in motor learning)
What cerebellar gait has circumduction (circling of extremities)?
Hemiplegic
Which cerebellar gait is observed in cerebral palsy?
Spastic diplegic
Which cerebellar gait has a “foot drop” aka neuropathy?
Neuropathic
Which cerebellar gait has “waddling”?
Myopathic
Which cerebellar gait has shuffling/bradykinesia (slow movements)?
Parkinsonian
Which cerebellar gait has dance-like movement?
Choreiform
Which cerebellar gait has a wide BOS (base of support) with arms out?
Cerebellar ataxic
Which cerebellar gait has high stepping?
Sensory ataxia
Standing posture with cerebellar ataxic gait?
May have postural sway (front to back or side to side), wide base of support
Characteristics of cerebellar ataxic gait?
Clumsy movement w/ wide BOS, Arms out for balance, Difficulty walking in straight line or tandem gait (heel-to-toe), veering to one side, uncoordination of LE & UE
With cerebellar ataxic gait, movement tends to veer to the side ______ to the cerebellar lesion
ipsilateral
Do cerebellar lesions impair motor activity?
Yes: impaired postural tone, loss of balance/equilibrium & coordination
Do cerebellar lesions result in motor paralysis?
No
Do cerebellar lesions impair ability to consciously detect sensory input (visual, auditory, vestibular, somatosensory)?
No
Are cerebellar lesions easy to detect (localize) during clinical exam?
No, prove challenging (not as precise as cortex)
Functional motor loss will be ______ to the side of cerebellar lesion
ipsilateral
What occurs with bilateral lesion of the cerebellum?
Bilateral motor function loss
What are the motor impairments observed with cerebellar lesions?
Hypotonia (reduced muscle tone), disequilibrium (loss of balance), dyssynergia (loss of coordination)
Appearance of hypotonia?
Floppy, rag doll, loose joint, pts. look drunk
Clinical exam procedures for hypotonia?
Observation, passive ROM, pendular deep tendon reflexes
Clinical exam procedures for disequilibrium?
-Standing balance (observe stance, narrow BOS tests, single leg stands)
-Observe gait (loss of balance)
-Tandem walking (heel-to-toe in straight line)
Types of dyssynergia?
Dysarthria, Dystaxia, Dysmetria, Tremor (intention tremor), Dysdiadochokinesia, Nystagmus, Decomposition of movement, Rebound (overshooting)
Features of dysarthria?
Uncoordinated speech, difficulty articulating, slur, slow speech, scanning of speech (random inappropriate variation in volume, emphasizing wrong syllable/vowel)
Clinical exam procedures for dysarthria?
Observation (listening) to speech
Features of dystaxia (ataxia)?
Lack of coordination w/ execution of learned voluntary movement
Sub types of dystaxia (ataxia) used for documentation?
gait ataxia, trunk ataxia, leg/arm ataxia
Clinical exam procedures of dystaxia (ataxia)?
Trunk stability in sitting, standing posture, gait, ADLs (reaching, etc)
Features of dysmetria?
Past-pointing, overshooting, inability to stop muscle movement at desired point
*performance can deteriorate (maybe do it first time but cannot repeat it)
Clinical exam procedures for dysmetria?
Finger to nose, heel to shin, finger to finger (point-to-point)
Features of intention tremor?
Tremor w/ precise voluntary movement (increases as pt approaches target)
Clinical exam procedures for intention tremor?
Pt. performs precision task (pick up a cup, point to specific spot, etc.), finger to nose, heel to shin, finger to finger (point-to-point)
Features of dysdiadochokinesia?
Inability to perform rapid alternating (RAM) or repetitive movement, disruption in timing of movement (initiation/stopping)
Clinical exam procedures for dysdiadochokinesia?
ask pt to perform RAM, rapid supination/pronation, rapid heel-to-toe in seated position, marching in seated position, rapid flat hand tapping
Features of nystagmus?
ocular dysmetria/spontaneous eye movement, rhythmic oscillation of eyeballs
Clinical exam procedure for nystagmus?
Observe pt.’s eyes when looking at extremes or moving in certain directions
Features of decomposition of movement?
Breaking down of SM activity (jerky), awkward fragments, poor timing
ex: w reaching (shoulder, elbow, then wrist w individual steps)
Clinical exam procedures for decomposition of movement?
Observe pt performing specific activity (reach for something on the shelf, etc.)
*pts movement fragmented in individual steps
Features of rebound dyssynergia?
Inaccurate return of extremity to start position after forceful resistance
Rebound = reciprocal overshooting or undershooting movement
Clinical procedures for rebound dyssynergia?
-Arm pull test: hold pt’s arm w elbow flexed and abruptly let go
-“Arms extended” test: have pt hold arms out straight, push down on pt’s hands, observe for rebound response
