Developing brain & nervous system pt. 1

Neuron

•  process electrical and chemical info and transmit info (action potential) to other neurons

synapse

connects axon terminals of transmitting cell to dendrites of receiving cell - (up to 1000 connections)

neurotransmitters

• Neurochemical exchanged btwn cells

serotonin

• mood altering, quiet alertness, and feelings of well-being (too little causes depression)

dopamine

attention, pleasure, optimism

too little dopamine

•  thought disturbances [schizophrenia]

•  movement disturbances [Parkinson’s])

types of neurotransmitters

• serotonin

• dopamine

2 types of neurons

• afferent

• efferent

afferent

• carry sensory info to CNS (afferent arrives)

efferent

• carry motor commands away CNS (efferent exits)

central nervous system

• brain

• spinal cord

• sense organ of skin

sense organ of skin

ectoderm layer

• [skin, muscles, etc] of embryonic disk

hindbrain

brain stem

• Basic physiological processes (breathing, heart, etc)

• Damage → vegetable state

midbrain

limbic system

• Processes info

• How brain processes emotional info?

forebrain

cortex

• Controls advanced level processing & ability to see, hear, taste

brain stem - autonomic nervous system

• Regulates basic body functions (afferent & efferent neurons)

• Has 2 branches

  • Sympathetic

  • Parasympathetic

• Infants (& adults) need balance btwn arousal and rest

  • Imbalance = problems

sympathetic

prepares body for action

parasympathetic

allows body to rest

limbic system

• hippocampus

• amygdala

• hypothalamus

hippocampus

• autobiographical memories

  • Ability to remember things that happened in your life

amygdala

• emotional memories (senses threat/stress sends neurochemicals to hypothalamus)

hypothalamus

•  links brain to hormonal system (pituitary & adrenal glands - HPA-axis) to help w/ states of arousal, feeding, self regulation

  • (e.g., cortisol hormone; oxytocin hormone)

  • Need to be aroused enough to do things like feeding, self regulation

HPA-axis

hypothalamus pituitary adrenal

cortisol hormone

hypothalamus

• prepares body for action in response to stress [flight/fight]

oxytocin hormone

hypothalamus

• feelings of comfort/safety [love hormone]

cortex lobes

• occipital

• temporal

• parietal

• frontal

occipital

processes visual info

temporal

auditory & speech processing

parietal

connected to muscles & sense organs

frontal lobe

• advanced processing such as problem solving, regulating emotions, reasoning, organizing behavior

prefrontal cortex

•  allows for voluntary instead of automatic (reflexive) patterns of behavior

  • Where advanced processing goes

  • Walking, talking

synaptogenesis

Each time you have new experience, make new dendritic connection

most rapid

connections btwn neurons most what during prenatal (25% of adult weight) to up to 2 yrs. postnatal (25% to 75% of it’s eventual adult weight

radial glial

helper cells

• help new neurons migrate to right place

first 4 months of prenatal development

Virtually all of one’s lifetime supply of neurons, “neurogenesis” produced during…

fetal brain development at 25 weeks gestation

period of developing inside uterus btwn conception and birth

25%

• of connections created before born

>37 weeks gestation

• Fetal brain development at term

overproduce synapses

Initially we what (by 12 months have 150% of adult #) which get “pruned” back to make stronger connections.

pruning

selective death of unused neurons

synaptic connection

repeat experience multiple times to form…

inc brain size by 25%

Developmentally supportive interactions can…

•  (e.g., good nutrition, providing opportunities for practice, and providing pos, loving touch, and social interactions)

myelination

 (through glia cells) coats axon and speeds up transmission of info

white matter

• uses info more efficiently in brain

• don’t get all of it til 25 yrs

inc, dec

white matter blank, grey matter blank w/ age

maturation of pre-frontal cortex

• Sleep becomes more regular and consolidated

• Emotional regulation - can efficiently self soothe

  • E.g., sucking thumb

• Dec tantrums/control tears

brain lateralization

every task we use both sides of brain

• left

• right

left brain

• Language

• Logical reasoning

• Detailed analysis

• More rapid changes after 2 yrs

right brain

• Visual spatial

• emotional/social/creative

• Holistic (big pic)

  • Most of occipital lobe on this side

• Change rapidly during first 2 yrs

corpus calossum

• Connect hemispheres so they can communicate. All tasks use both sides

• When getting lobotomy, this is cut

Left brain

• Controls right side of body

Right brain

Controls left side of body

postnatal rate of development

• Diff areas of brain develop at diff rates (e.g., visual cortex matures much earlier than prefrontal cortex)

• Synapses connect and disconnect all the time. Not steady growth and decline process

  • Surge in one area, dependent on experiences

experience-expectant functions

• brain expecting specific experiences which causes specific skills (e.g, pain causes crying/acquiring language by hearing speech)

  • Things we kind of automatically learn

experience-dependent functions

• most cells and synapses open to specific, individual learning experiences (e.g., learning specific language, how to play musical instrument/completing puzzles)

  • Never completed puzzle before, not going to know how to complete one

threat

• sense of being in danger from outside of ourselves