Chapter 4: Early 1 and 2 Flashcards
Recall the maturational perspective on development suggests the brainstem/spinal cord, midbrain and cerebral cortex affects what reflexes/reactions?
Recall the maturational perspective on development
Brainstem/Spinal Cord → Primitive reflexes
MidBrain → Righting reactions
Cerebral cortex → equilibrium reactions
As the brain develops, the maturational perspective suggests that the CNS was the sole constraint to guide early motor behavior which implies?
unidirectional control
Is this really the case?
it seems not. Recent evidence suggests that movement also affects brian development (again, the interaction is key)
This helps to explain movements that had not really been considered by aerie er researchers: Those that appear randomly, or spontaneously
Are the random movements reflexive?
No
They occur in the absence of any apparent stimulus (or for any apparent reason)
Spontaneous (Steretypie) movements
Spontaneous Movements
Are the infants movements that occur without any apparent stimulation
Examples: Supine kicking, spontaneous movements
who studied supine kicking?
Thelen and Colleagues (1985, 1995)
Thelen et al. studied spine kicking movements by analyzing position and timing of limb segments what did they find?
Movements are not random
They are rhythmic and coordinated
Ankle, knee, and hip joints move cooperatively (not independently)
What does the patterns of the spontaneous movements of supine kicking in infants show?
These patterns appear to be early precursors of walking
How do infants tend to use their muscles?
Infants tend to co-contact their muscles (flexors and extensors contracted) adults are more efficient
Spontaneous arm movements (pre-grasp reaching) another stereotypies
Again, high degree of coordination of elbow, wrist, and finger joints
Note the fingers do not extend independently
Why do stereotypies exist?
Newborn musculature is underdeveloped
Lack of ability to produce intentional, goal-directed movements
Spontaneous movements og and current theory:
Original theory: movements are extraneous, with no purpose
Current theory:
Movements are “building blocks”, are similar to, and serve as a function for some voluntary movements
The developing brain results in the generation of these movements (maturational) the movements in turn shape the development of the brain (ecological)
These stereotypes are one example of early (pre-adaptive) motor behaviors. what is another movement that arises from this?
Another is movements that arise as the result of reflexes
Infantile Reflexes:
Reflexive movements occur quickly after the onset of stimuli
They involve single muscle or specific group of muscles (not the whole body)
They can not be extinguished at any one time
Persistence many indicate neurological problems
Are reflxes voluntary or involuntary?
involuntary after a stimulus
When do reflexes begin to develop?
Dominant movement from during the last 4 months of prenatal life (i.e begin to develop in utero) and the first 4 months after birth
Where in the brain to reflexes occur?
Occur subcortically (below the level of the higher brain centers)
Why do reflexes occur?
Built-in response, facilitates survival
Allows interaction with the environment
Reflexive movements result in sensory consequences, stimulate development
During later portion of reflexes period, reflex are modulated “building blocks” for future movement
How many reflexes?
There are approximately 27 major infantile reflexes (most are suppressed at about 4-6 months of age)
General Types of infantile reflexes:
Primitive: survival and protection
Postural: reaction to gravity
Locomotor: resemble voluntary locomotion
Asymmetric tonic neck reflex (primitive)
Infant starts in supine position stimulus : turn head to one side Response: same-side arm and leg extend Facilitates bilateral body awareness Facilitates hand eye-coordination Also called “bow and arrow” or “fencer’s” position
Symmetric tonic neck reflex
Infant starts sitting
Stimulus: tip forward
Response: neck and arms flex, legs extend (tip back, neck and arms extend, legs flex)
Faciliatest equilibrium (vestibular development)
Persistence may impeded many motor skills and cause spinal flexion deformities
Doll eye reflex
Infant starts in vertical position
stimulus: movement to supine and back to vertical
Response: Eyes open and close
Facilitates vestibular development
Triggers of sleep and alertness
Persistence after first few days may indicate a problem
Palmar grasping
Stimulus: touch palm with finger or object
Response: hand closes tightly around object
