+ All Categories
Home > Documents > Brain Development Psyc of Violence Jen Wright. There are a lot of physical changes that happen...

Brain Development Psyc of Violence Jen Wright. There are a lot of physical changes that happen...

Date post: 19-Dec-2015
Category:
View: 218 times
Download: 2 times
Share this document with a friend
Popular Tags:
39
Brain Development Psyc of Violence Jen Wright
Transcript

Brain Development

Psyc of ViolenceJen Wright

There are a lot of physical changes that happen during the first years of life,

The most important (and dramatic) of which is brain development.

One of the last organs to fully develop…

brain development Largest brain/body mass of any animal. Encephalization Quotient (EQ) = 7.4

•Dolphin = 5.3•Chimp = 2.5•Elephant = 1.9•Whale = 1.8

Most development happens outside (instead of inside) the womb•Monkey newborn 70% adult size•Human newborn 25% adult size

Most growth occurs in first 3 yrs•3 yr old 80% adult size

brain development Neurogenesis – proliferation of neurons

through cell division•At peak, 250,000 cells “born” every minute

Synaptognesis – formation of connections•Each neuron forms thousands of connections

•Axons elongate towards specific targets

•Dendritic “tree” increases in size and complexity

•6 mos have 2 x more synaptic connections

Synaptic pruning – elimination of excess synapses•Streamlines neural processing

•Without synaptic pruning, children wouldn't be able to walk, talk, or even see properly.

Myelination – insulating sheath•Happens at different rates into adolescence

•Certain areas are myelinated first

importance of experience Plasticity – brain’s ability to change w/

experience Experience-expectant plasticity

(experiences present throughout evolution)•Economizes on material encoded in genes

•Development will occur within a normal range of environments

•Level of vulnerability in timing•Critical periods

importance of experience Experience-dependent plasticity

(experiences of individual)•Brain sculpted by idiosyncratic experiences

•Brain responsive to richness of stimuli

•Important in development of expertise•More brain resources dedicated to processing

•E.g. musicians’ cortical representation of hands

•Timing may be less important•Sensitive periods

Why are abusive environments so damaging for children?

There are many reasons

Effect of deprivation

REM sleep – critical for neural development in brain, esp. for activity-dependent development•E.g. visual system

•Facilitates learning/memory Sleep deprivation linked with later

problems•E.g. ADHD, behavior-problems

Babies most at risk of disruption•Premature infants in IC units

•Erratic, abusive environment

What is attachment? Attachment refers to the close,

emotional bond between an infant and his/her primary caregiver.

Orbital-frontal cortex: connects processing of incoming sensory stimulation with internal emotional experiences

Early views of attachment Psychoanalytic Theory (Freud)

•Driven by oral needs during the first year

•Emphasized early experiences on later outcomes

Behaviorist Perspective •Driven by the need for food

•Learns to associate contact with mother with food

•Mother’s closeness continually reinforced

Ethology Rooted in Darwin’s

Evolutionary Theory Focused on the

adaptive value of behavior

Bond necessary for survival

Lorenz (1952) - Imprinting

Primary criticism of these early perspectives Love (i.e., attachment) seen as

secondary to instinctive or survival needs

Harlow believed that the love and affection were central to attachment•necessary for survival

Harlow’s Monkeys (1958) Early work with monkeys Cloth & wire mother

•Only one equipped with feeding apparatus

•Monkeys randomly assigned

•Observed for 5 months Both groups preferred cloth mother

Contact Time with Wire and Cloth

Surrogate Mothers

24

0

6

12

18

21-251-56-10

11-1516-20

Age (in days)

. . . ..

. . . ..

.

.

.

.

.

.....

Infant monkey fed on wire mother

Infant monkey fed on cloth mother

Hours per day spent with wire mother

Hours per day spent with cloth mother

Mean hours per day

Violence papers:•Incorporate my comments

•Expand to begin providing explanations (using the frameworks we’ve discussed so far)•3-4 pages (double-spaced)

•Bring 2 copies (printed and stapled/clipped)

http://www.youtube.com/watch?v=hsA5Sec6dAI

http://www.youtube.com/watch?v=caM4-f6ZZBE&feature=related

mirror neurons Found in the frontal and parietal lobes Fire when you

•engage in an activity (reaching out one’s hand)

•observe someone else engaging in the same activity.

Fire more strongly when action has some purpose or content •reaching out one’s hand for a cup.

MN’s play a clear role in learning/imitation. May also play a role in “mind-reading”

•grasping intentions, goals, desires.

crying Crying – infant form of

communication•Response to distress

•Development of emotional self-regulation

•Mastery of environment – agency

•Biofeedback loop

When an infant’s needs are met, they are able to turn their focus to the world around them and explore.•Their brains take in and adapt to

stimulation from the external world. When they aren’t met, they become

fixated on trying to get their needs met•They stop exploring and shut out other

stimulation from the external world.

Prolonged crying expose the brain to high levels of cortisol, adrenaline, and other damaging chemicals.•Damage to hippocampus

•Reduced levels of vasopressin and serotonin

•Reduced levels of emotional regulation

• Impaired memory

• Increased levels of aggression/violence/bullying

• Increased levels of anxiety disorders

stress and brain development

Exposure to excessive stress hormones is bad for brain development.

Early symptoms of PTSD The brain can become incapable of

producing normal stress responses.•Hyper-vigilance (Ghosts in the Nursery)

•Emotional flatness Physical/emotional abuse and neglect can

be equally damaging.

emotions and cognition: bi-directional

Emotional reactionsLimbic systemo amygdala/hippocampus link

o Lead to learning that is essential for survival

Influence how a situation is perceived, interpreted, and remembered.

o Improve memory of evento Highlight issues of importanceo Make things personally

relevant

o Create life-long positive/ negative associations

emotional self-regulationStrategies learned for adjusting emotional state to a

comfortable (adaptive) level of intensity in order to accomplish goals.

Sympathetic: child more easily soothed,more interestedmore self-regulated

Non-responsive (wait to intervene): child enters into rapid, intense distressharder to soothedoesn’t develop self-regulation

temperament Constitutionally based individual

differences in •Emotion

•Motor function

•Attentional reactivity

•Self-regulation Influences the way that children

develop, display, and control emotions Foundation for later personality

Temperament styles Types

•Easy

•Difficult

•“Slow to warm up” Differences in punishment/reward Differences in sociability Bi-directional issues

•Gender

•Cultural differences

•Goodness of fit (with parents/environment)

Neurotransmitters•Serotonin

•Noradrenaline Hormones

•Testosterone Adrenaline/Cortisol

Gene/Environment InteractionTwo levels of environmental influence:

Environment

Genes: Genotype

Genes: Phenotype

Gene/environment interactions

Passive genotype-environment correlation. Evocative genotype-environment correlation. Each child’s genes elicit other people’s

responses, and these responses shape development. • In other words, a child’s environment is partly the

result of his or her genes. Active genotype-environment correlation. Children, adolescents, and especially adults

choose environments that are compatible with their genes (called niche-picking), • thus genetic influences in adulthood increase.


Recommended