Ch 6
Spontaneous supine kicking and walking:
- Supine kicking was not random but rhythmical and the kicks had a coordinated pattern • Infant's kicks are similar to an adult's walking steps, but not identical. • Co‐contraction of flexors and extensors muscles (infants tend to activate both muscles for flexing the limb and extending the limb) • Unison ---> move hip, knee, and ankle sequentially after 1 yr rather than tight unison
Appearance and Disappearance of Reflexes: • Primitive reflexes start to weaken or become modified _________. - An individual may deviate from typical in two ways: * Exhibiting a reflex when the individual should not * Not exhibiting a reflex when the individual should • eg) Babinski reflex- which is:
- after 2 weeks - running a probe along bottom of patients foot; toes extend
Primitive reflexes: around from the ______. - an ______ response to specific stimulation that is often mediated by lower brain centers
- beginning -involuntary
Locomotor Reflexes- Moving in Place: • LRs appear much earlier and typically disappear months before their voluntary locomotor skill - examples of locomotor reflexes:
- crawling, stepping, swimming
Relationship of Reflexes to Voluntary Movement: - idas about the relationship between reflexes and later movement has changed ______ over the past 50 years • Early researchers (McGraw) believed infants could not move voluntarily until reflexes has been inhibited by _____; a theory called: _____. • _______ et al (1972)., found relationship between two. * Daily practice : ↑ _____ and earlier onset of _______. • ________(1983), proposed that other constraints may be related to the disappearance of the stepping reflex, rather than strictly maturation.
- drastically - CNS; motor interference - Zelazo, stepping reflex; voluntary walking - Thelen
Primitive reflexes vs. spontaneous movement: • Responses to specific _________ • Specific and often _______ • Same stimulus will elicit a specific reflex ______
- external stimuli whereas spontaneous movements do not result from any apparent external stimuli - localized whereas SM tend to be non specific and generalized - over and over
Motor Milestones: • are _________ motor skills, the attainment of which is associated wit the acquisition of later voluntary movements. The order in which an infant attains these milestones is relatively consistent, although the timing differs for individuals • Building blocks (leading to complex motor skills) • Cumulative, sequential eg) To walk: stand ---> hold trunk upright ---> hold head upright • Specific movements that lead to general actions
- fundamental
Postural Reactions: Moving Upright in the World • ______ reflexes • help infant ________ in a changing environment • Appear after ______ old • PRs don't literally disappear.
- gravity - maintain posture - 2 months
Rate Limiters, or Controllers: • Individual constraints that ______ attainment of a motor skill • Rapidly changing during early childhood * E * E * C
- inhibit or slow - experience - environmental -culture
Reflexes:
- involuntary movements that an individual makes in response to specific stimuli
Bayley and shirley observed infants and determined a sequence of motor milestones as well as average ages at which the infants achieved them. This progressive pattern can be related to predictable changes in the individual constraints that occur in typically developing infants. These include:
- maturation of the CNS - development of muscular strength and endurance - Development of posture and balance - Improvement of sensory processing
Spontaneous Movements: • Infants' movements that occur without any apparent stimulation. • Fundamental building blocks, similar to some voluntary and fundamental movements • Examples: * Spontaneous arm movements (resemble _____) * Spontaneous kicking (resembles ________)
- reaching - adult walking
Development of Postural Control and Balance in Infancy: • Rate limiters for posture and balance appear to involve coupling of ____________. • Infants continuously calibrate sensory motor response
- sensory information and motor response.
(primitive reflex) Moro Reflex • Infant starts in supine position. • Stimulus: ______ (e.g., by tapping pillow). • Response: Arms, legs, and fingers ____; fingers spread, then arms and legs ____.
- shake head - extend, flex
Spontaneous arm movements:
- show well- coordinated extension of the elbow, wrist, an finger joints - Fingers do not extend independently but rather in unison with hand, wrist, and elbow - arm movements are not as rhythmical and repetitious like leg kicks - arm thrust aren't identical to adult reaching movements - takes infants several months to open their fingers independently of other joints and grasping objects - these spontaneous movements affected by environmental constraints
Early Motor Behavior- infants exhibit: • _________________ movements not caused by known external stimuli • _____________ stereotypical responses elicited by specific external stimuli (Clark, 1995)
- spontaneous - reflexive
(primitive reflex) Asymmetrical Tonic Neck Reflex: • Infant starts in _____ position. • Stimulus: Turn head to _______. • Response: _______ arm and leg extend
- supine - one side - Same‐side
Purposes of Reflexes: • Built‐in responses facilitate _______. • Byproduct of the neurological system • Reflexes allow "_______" with environment. • Reflexive movements result in _________. • reflexes provide building blocks for ______.
- survival - dialogue - sensory consequences (adaptation) - future movement.
Labyrinthine righting reflex: • Infant is supported _____. • Stimulus: _____ • Response: ______ to stay upright.
- upright - tilt infant - head moves
Infantile reflexes • Involuntary movements/Reflexive movements occur quickly after onset of ______. • Often visible in young infants • _____ • _____ • _____ • They cannot be extinguished at any one time. • Persistence may indicate neurological problems.
-stimuli - primitive reflexes - postural reactions - locomotor reflexes
Infant does not have to think about making reflexive movements; they occur ________
automatically
