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Psyb20 ch5.docx

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Department
Psychology
Course
PSYB32H3
Professor
Mark Schmuckler
Semester
Winter

Description
Psyb20 ch5 Brain development in infancy -cerebrum: a mass of tissue that embodies not only attributes particular to humans such as speech and self awareness but also sensory perception, motor abilities and memory -cerebral cortex: contains about 90% of the brain’s cell bodies neurons and synapses -most neurons are present in the brain by the seventh month of gestation -during the embryonic period, neurons multiply at a very rapid pace in a process call neuron proliferation -the adult brain has the capacity to regenerate nerve cells -glial cells: provide neurons with structural supports and regulate their nutrient and repair neural tissue, some of them are also responsible for cell myelination -myelination occurs during the first 2 years of life all the way to adulthood they allow for quicker transmission of messages -neural migration: ensures that all parts of the brain are served by a sufficient number of neurons -the absence of neurons can be associated with mental disorders such as dyslexia or schizophrenia -synapseS: are the connections between neurons allow for complex communication to occur -synaptogenesis: is the forming of synapses and occurs early in prenatal life -when new synapses are formed, some surrounding neurons die in what is called neuronal death also known as programmed cell death -in synaptic pruning, the brain disposes of a neuron’s axons and dendrites id that particular neuron is not often stimulates-use it or lose it -neuronal death and synaptic pruning are to increase the speed, efficiency and complexity of transmissions between neurons and to allow room for new connections that develop as the child encounters new experiences We don’t want too many neurons everywhere hogging up space so synaptic pruning occurs where unused synapses die in order to make room for new connections that aid new child encounters Sequential development of the brain There is an orderly sequence to brain development during infancy Hemispheric specialization -the left and right hemispheres are connected by the corpus callosum -when one side of the brain suffers damage the other half may take over some functions Left and right brain functions -hemispheric specialization: where each side of the brain carries it out its own specific functions -left hemisphere controls movement of the right side and vice versa -lateralization: descirbes the specialization of each hemisphere in specific perceptual and cognitive tasks -the right hemi: visual spatial info, sounds like music and the perception of faces and their emotions -damage to the right side causes difficulty attending to a task requiring visual spatial perception -because it is involve in emotional processing, you may have difficulty interepreting emotional expression -left hemisphere is activated in the expression of emotions associated with approach to the external environment, such as joy, interest and anger, whereas the right region is activated in emotional expression that cause the person to turn away or withdraw from that environment -the left hemisphere is involved in language processing -trouble understanding what is being said to them or in speaking clearly themselves -deaf people use sign language, and the right side of the brain takes over language functions for them -because the brain is not fully done dev, if injury occurs in the early years infants and children may have the chance to recover from their losses Consequences of brain lateralization -infants whose left hemisphere differentiates among speech sounds and whose right hemispheres differentiate among non speech sounds exhibit better languages skills at 3 than infants who do not show lateralization -dyslexia: difficulty some children experience in learning to read -they have difficulty integrating visual and auditory information such as matching letters or words to the sounds of those letters and words -children with dyslexia do not show the normal lateralization pattern, they process spatial information on both sides of the brain rather than primarily on the right and thus their left hemi may become overloaded leading to deficits in language skills such as reading -some left handed people are ambidextrous and this suggests that their brains may be less clearly lateralized than the brains of right handed people The brains plasticity: experience and brain’s development -stimulation from the environment plays a role in brain development -the brain is plastic, can be changed and reformed depending on environmental interactions -affected by 2 types of experiences: -experiences such as touch, patterned visual input, sounds of language, affectionate expressions from caregivers and nutrition, may trigger synaptic development and pruning and are critical to normal brain development -second kind are experiences that are unique to individuals, such as experiences encountered in a particular family, communities and cultures -brains respond to different environments by developing synaptic connections that encode specific and unique experiences -enriched environments tend to increase the complexity of neurons as measured by the number of dendrites they develop* in enriched environments there tends to be more dendrites because there is more communication going on* -more dendrites means more synapses which means more information can be sent via these synaptic connections -so the brain develops better in highly enriched environments -exposure to music can also enrich brain development *music is stimulatory soo it’ll enrich brain development* -some research demonstrates that the brain can undergo structural change based on unique experiences even in adulthood -in abused children both the cortex and the limbic system (emotion system and parent infant attachment systems) are 20 to 30 percent smaller and have fewer synapses than in non abused children *brain develops according to environment* Motor development Hand skills -reaching out and grasping an object is one of the greatest achievements in the first 2 years of life -prereaching is seen early when the baby tries to swipe at things in its view -5 months old they generally succeed in reaching for an object -to achieve this involves muscle growth, postural control, control over movement of arms and hands, and a variety of perceptual and motor abilities (they all need to work together) -all these are part of the dynamic system -first needed is visual perception: nothing to look at, there is no incentive to reach out -next is motor ability to grip and object: grip improves with age and depends on the size of the objet relative to the size of the hand Locomotion -how dooes walking develop? -maturational theorist say it depends on development of the motor cortex -cognitive theorist believe that it is a response to cognitive plans on representations that are consequences of watching other people walk -in reality it is like grasping and involves a dynamic systems theory -walking skills are determined by the interplay of a variety of emotion, perceptual, attentional, motivational , postural and anatomical factors -babies size and weight can be a heavy load, and can mask the childs stepping capability -12 months should be able to step as long as they are given the stability and postural support necessary to do so Should be able to walk between 12 and 18 months How locomotion may affect other aspects of development -consequences of locomotor dev is increase independence -that early walking is related to increase parent-child interaction and more “testing” of wills between mothers and their children -schmuckler: motor or action systems are functionally interrelated to sensory or perceptual systems such that changes in one aspect influence the development of the other aspect -researchers have suggested that the onset of locomotion can change the way babies understand their perceptual world-schmuckler ex: the onset of crawling bring with it a fear of heights and other spatial abilities -locomotion helps infants deal better with changes in spatial orientation (moving room) The role of experience and culture -the timing of the onset of various skills may be affected by societal and other factors -cross cultural studies have provided us with information about how specific ways of caring for infants can alter their motor development -caretakers give babies special physical attention -infants achieve motor milestones somewhat earlier than children not given such care and opportunities -parents who show more physical caretaking, preparing them for walking, the infants will dev motor skills earlier -practice earlier can also help babies learn how to walk faster -with more walking experience were the most skilled walkers -but there are limits to how far infants motor development can be pushed -infants born in the summer or fall acquired motor skills later than infants born in winter or springs because the former group would begin to develop locomotor skills in the winter to early spring -a time when motor skills might e constrained due to more restrictive clothing and activity reducing illnesses Physical growth -cephalocaudal: growth from head to toe -proximal distal: from centre outward, the internal organs develop earlier than do the arms and hands -but those are not true for everything -height and weight are 2 principle measures of overall growth -babies grow faster in their first
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