Brain and Behavior Week 2 Flashcards
Cerebellum: functions (3)
Balance and stability; coordination of movement; cognition and learning
Cerebrocerebellum: deep nuclei
Dentate
Cerebrocerebellum: cerebellar region
Lateral hemispheres
Spinocerebellum: cerebellar region
Paravermis, vermis
Spinocerebellum: deep nuclei
Interposed (paravermis), fastigial (vermis)
Vestibulocerebellum: deep nuclei
Vestibular n.
Vestibulocerebellum: cerebellar hemisphere
Flocculonodular lobe
Cerebrocerebellum: inputs
cortical afferents (pontine)
Cerebrocerebellum: outputs
motor, premotor cortex
Spinocerebellum: inputs
spinal afferents (P-distal, V-axial); facial, visual, auditory, vestibular inputs (V)
Spinocerebellum: outputs
lateral (P) / medial (V) descending systems
Vestibulocerebellum: inputs
vestibular labryinth
Vestibulocerebellum (outputs)
vestibulocpinal, MLF
Symptoms of cerebellar dysfunction
cerebellar ataxia (lack of accuracy or coordination of movement not due to other causes)
Ataxic gait
Wide-based, lurching/staggering gait; Steps are short, unequal in length and irregular; arms don’t swing synchronously w/opposite leg; speed of gait is reduced
Truncal ataxia / titubation
Inability to coordinate the muscles used while sitting still; titubation = truncal tremor (can be front to back, side to side, or rotary)
Dysmetria
Limb ataxia: arms > legs, complex movements > simple movements, fast movements > slow movements
Finger to nose test: initiation of movement is delayed, movement is decomposed, path of movement of finger is erratic and jerky (overshooting and undershooting)
Dysdiadochokinesis
Impairment in executing rapid alternating movements; test by tapping each finger to thumb in succession, or by patting leg with hand, alternating palm and dorsum of hand
Nystagmus
Abnormal jerking eye movements w/fast phase in one direction and slow, corrective phase in the other; Slow fast is toward the primary eye position
Ocular dysmetria
On attempted fixation, eyes may overshoot target and oscillate until fixation is obtained
Ataxic dysarthria
Disruption of metrical nature of speech (intervals too long or short, incorrect emphasis on syllables), speech may be harsh or monotonous.
Scanning speech: slow and deliberate production of strings of syllables, sometimes punctuated by explosive syllables
Tone
resistance to passive movement
Juvenile pilocytic astrocytoma
Usually present within the first 2 decades of life; peak presentation @ age 10; patients present w/HA, nausea, vomiting; surgery usually curative (>90% 5y survival)
Cerebellar mutism
decreased or absent speech, irritability, hypotonia, ataxia most commonly seen after surgery in the posterior fossa; severe incoordination in volitional motor aspects of speech; may be immediate or delayed; recovery is the rule
Posterior fossa tumors
more common in children than adults
Chiari I malformation
caudal displacement of the cerebellar tonsils below the FM; usually a static problem; 4th ventricle is in normal position
Dandy Walker Malformation
cystlike dilation of the 4th ventricle; absent cerebellar vermis; enlarged posterior fossa (picked up early due to developmental delays)
Joubert Syndrome
hypoplasia of the cerebellar vermis; molar tooth sign on imaging; breathing abnormalities, hypotonia, eye movement abnormalities; ataxia, mental retardation
Post-infectious cerebellitis (acute cerebellar ataxia)
thought to be autoimmune; post-inflectious inflammatin of the cerebellum; typically seen in children under the age of 5; explosive onset of gait ataxia and nystagmus; full recovery over period of weeks to months; usually attributable to an antecedent viral infection (Varicella)
Paraneoplastic cerebellar degeneration
tumor-associated degeneration, often associated w/specific anti-neuronal antibodies
Spinocerebellar ataxia (SCA)
autosomal dominant; slowly progressive gait and limb ataxia associated w/akinesia, rigidity, tremor, hyporeflexia
