Brain and Behavior Week 2

Question 1

Cerebellum: functions (3)

Answer 1

Balance and stability; coordination of movement; cognition and learning

Question 2

Cerebrocerebellum: deep nuclei

Answer 2

Dentate

Question 3

Cerebrocerebellum: cerebellar region

Answer 3

Lateral hemispheres

Question 4

Spinocerebellum: cerebellar region

Answer 4

Paravermis, vermis

Question 5

Spinocerebellum: deep nuclei

Answer 5

Interposed (paravermis), fastigial (vermis)

Question 6

Vestibulocerebellum: deep nuclei

Answer 6

Vestibular n.

Question 7

Vestibulocerebellum: cerebellar hemisphere

Answer 7

Flocculonodular lobe

Question 8

Cerebrocerebellum: inputs

Answer 8

cortical afferents (pontine)

Question 9

Cerebrocerebellum: outputs

Answer 9

motor, premotor cortex

Question 10

Spinocerebellum: inputs

Answer 10

spinal afferents (P-distal, V-axial); facial, visual, auditory, vestibular inputs (V)

Question 11

Spinocerebellum: outputs

Answer 11

lateral (P) / medial (V) descending systems

Question 12

Vestibulocerebellum: inputs

Answer 12

vestibular labryinth

Question 13

Vestibulocerebellum (outputs)

Answer 13

vestibulocpinal, MLF

Question 14

Symptoms of cerebellar dysfunction

Answer 14

cerebellar ataxia (lack of accuracy or coordination of movement not due to other causes)

Question 15

Ataxic gait

Answer 15

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

Question 16

Truncal ataxia / titubation

Answer 16

Inability to coordinate the muscles used while sitting still; titubation = truncal tremor (can be front to back, side to side, or rotary)

Question 17

Dysmetria

Answer 17

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)

Question 18

Dysdiadochokinesis

Answer 18

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

Question 19

Nystagmus

Answer 19

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

Question 20

Ocular dysmetria

Answer 20

On attempted fixation, eyes may overshoot target and oscillate until fixation is obtained

Question 21

Ataxic dysarthria

Answer 21

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

Question 22

Tone

Answer 22

resistance to passive movement

Question 23

Juvenile pilocytic astrocytoma

Answer 23

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)

Question 24

Cerebellar mutism

Answer 24

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

Question 25

Posterior fossa tumors

Answer 25

more common in children than adults

Question 26

Chiari I malformation

Answer 26

caudal displacement of the cerebellar tonsils below the FM; usually a static problem; 4th ventricle is in normal position

Question 27

Dandy Walker Malformation

Answer 27

cystlike dilation of the 4th ventricle; absent cerebellar vermis; enlarged posterior fossa (picked up early due to developmental delays)

Question 28

Joubert Syndrome

Answer 28

hypoplasia of the cerebellar vermis; molar tooth sign on imaging; breathing abnormalities, hypotonia, eye movement abnormalities; ataxia, mental retardation

Question 29

Post-infectious cerebellitis (acute cerebellar ataxia)

Answer 29

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)

Question 30

Paraneoplastic cerebellar degeneration

Answer 30

tumor-associated degeneration, often associated w/specific anti-neuronal antibodies

Question 31

Spinocerebellar ataxia (SCA)

Answer 31

autosomal dominant; slowly progressive gait and limb ataxia associated w/akinesia, rigidity, tremor, hyporeflexia