Topic 4

Question 1

infantile reflexes

Answer 1

• origin: prenatal period (2nd or 3rd month), most present at birth
• form the basis for all phases of motor development
• initially controlled subcortically by the spinal chord, then by the brain stem/midbrain as CNS matures, and become suppressed as cerebral cortex matures and voluntary movement takes over
• approx 27 major reflexes, most suppressed by 6mo-some re-emerge due to neurological trauma. coughing, blinking, and sneezing persist
• abnormal reflexes indicate damage to system

Question 2

rooting

Answer 2

-search reflex
stimulus-touching area around infant’s mouth
response-head turns toward touch, mouth opens and tongue extends
function-facilitates search for nipple (necessary for food when born)

Question 3

babkin reflex (palmar mandibular)

Answer 3

stimulus-pressure to both palms

response-opening of mouth, closing of eyes, and flexion of head (1 or all)

Question 4

sucking reflex

Answer 4

stimulus-nipple touching back of palate
response-jaw movements needed to express milk
step 2 stimulus-touching above or below lips
response-sucking

Question 5

palmar grasp/plantar grasp

Answer 5

stimulus-tactile stimulation of palm
response-fingers/toes flex (not thumb)
preposed function-preparation for voluntary grasping
-begins prenatally and endures to 4 months. retention can result in poor handwriting, poor fine motor skills and manual dexterity, and slumped posture over a desk
-absence indicative of neurological abnormalities (spasticity)

Question 6

Assymetric Tonic Neck Reflex

Answer 6

stimulus-head turning to side
response-limbs on face side extend, limbs on other side flex in supine/prone
preposed function-assistance in birthing, facilitating body awareness, developing hand-eye coordination
-retention after 6 mo impedes crawling

Question 7

babinski reflex

Answer 7

stimulus-stroking bottom/lateral portion of foot
response-big toe extends upwards and toes separate
-absence indicates immature CNS or lack of myelination
-retention after age 2=sign of damage to corticospinal tracts
-adults have the opposite response-babinski response in adults indicates CNS damage

Question 8

parachute reflex

Answer 8

stimulus-tipping an infant off balance
response:
1. when lowered rapidly, legs extend (from 4 mo)
2. when tilted forward or sideways, arms extend (7 mo and 6 mo)
3. when tilted backward, arms extend and body may rotate
function-attainment of upright posture/attempt to break fall
-persistence leads to broken wrists

Question 9

swimming reflex

Answer 9

when held horizontally-arms and legs move in swimming action (11 days-5mo)
-bradycardiac response-infants open their eyes and hold their breath underwater

Question 10

crawling reflex

Answer 10

stimulus-alternative stroking of soles of the feet (supine/prone)
response-arms and legs move in crawling motion
preposed function-essential for development of muscle tone needed for creeping
-birth to 4 months
-false crawling reflex: newborns placed on stomach move arms and legs (trying to turn over because they’d suffocate in the womb)

Question 11

primary stepping reflex

Answer 11

stimulus-placing infant upright with soles of feel touching surface
response-legs lift and descend
-not voluntary, no postural reflexes, not enough strength to actually walk

Question 12

spontaneous movements

Answer 12

• not a reflex, repetitive motions that appear in absence of stimuli
• ‘transitional behaviors’ some control over body parts but goal-directed action not possible-underlying temporal structure to movements
• highest frequency between 6 and 10 months
• increased frequency of movements found in children with down syndrome, tourettes, blindness, deafness, and schizophrenia
• 47 distinct movements (ex kicking)