Lecture 3: Prenatal, Brain, and Sensory Development Flashcards
pituitary gland
an endocrine gland controlled by the hypothalamus and produces growth hormone
thyroid gland
plays an important role in growth and development of the nervous system
- when a mother has problems with their thyroid gland, this can lead to intellectual problems in their offspring
- produces thyroxine hormone
testicles
produce testosterone, developing the male reproductive system during the prenatal period, and controls male sexual development during adolescence
ovaries
produce oestrogen and progesterone, regulating the menstrual cycle
- oestrogen controls female sexual development during adolescence
- progesterone ensures conception and supports pregnancy
adrenal glands
produce adrenal angdrogens, supporting the development of muscles and bones and contribute to sexual motivation
myelination
begins prenatally but continues for years after birth
cephalocaudal principle
growth occurs in a head-to-tail direction
- in the prenatal period, the head is much more developed than the rest of the body
- in proportion, a baby’s head is 25% of its length
proximodistal principle
babies grow and develop muscles from the centre to the extremities of the body
- the chest and internal organs develop first, followed by the arms, hands, and fingers
orthogenetic principle
development starts globally, but becomes increaseingly specific and follows a hierarchical integration
- a human begins as a single cell, but later consists of billions of specialised cells (neurons, blood cells, liver cells, etc)
- these cells start to organize themselves and integrate into a functional system
synaptogenesis
the development of connections between neurons (synapses)
- connections become stronger and stronger as synapses are used more and more, resulting in greater synaptic density
synaptic pruning
connections die when they are no longer used
reflexes
unlearned and involuntary responses to a stimulus
survival reflexes
reflexes with a clear adaptive value, such as the breathing reflex, the blink reflex, and the sucking reflex
primitive reflexes
reflexes which are not immediately useful
- some researchers believe they lost their function in evolution
- although not useful, helpful in identifying neurological problems
sleeping patterns of babies
- if children are still waking up frequently at 12 months, this may indicate attention and behavioral problems at the age of 3-4
lateralization of the brain
the asymmetric development of both brain hemispheres
left hemisphere
exercises control over the right part of the body and is needed for the sequential processing of language and problems
- “thinking” part of the brain
right hemisphere
exercises control over the left part of the body and is needed for the simultaneous processing of information needed for spatial information, visual-motor information, and the emotional change of information
- “emotion” part of the brain
puberty
a process of biological changes that result in sexual maturity
- grey matter grows in a U-shape
- white matter grows in a linear line through adolescence
explanations for adolescents risky behavior
- the part of the brain that regulates self-control is not yet fully developed; this makes teenagers vulnerable to risky behavior
- adolescents are more sensitive to rewards; the reward system in the brain (nucleus accumbens) is hyper-responsive, so it has a greater need for rewards
sexual maturity
- adrenal glands increase the production of androgens between ages 6-8
- hormones produced by the testes and ovaries are more evident for sexual maturity: sexual thoughts, feelings, and behaviors
menarche
the biggest change in sexual maturity for girls, the first menstruation
semenarche
the biggest change in sexual maturity for boys, the first ejaculation
environmental role in sexual maturity
secular trend: society is maturing earlier and earlier
- better nutrition, improved medical care, increased obesity, exposure to many chemicals
Tanner Scale
tracks sexual maturity
psychological implications of puberty and adolescence in girls
- become self-conscious about their appearance and start to worry about how others look at them
- possible development of a negative body image, with the increase in body weight as a possible cause
psychological implications of puberty and adolescence in boys
- boys hope to be tall and handsome
- more concerned about physical and athletic skills
- boys who develop later may experience difficulties in sports or in romantic relationships
early-developing boys
seen as socially competent, attractive, and confident
- increased risk of substance abuse, bullying, aggression, and delinquency
late-developing boys
more anxious and less self-assured
- experience more behavioral and adaptation problems, lower school results
- less likely to drink alcohol
early-developing girls
may be bullied because they are the only ones in the group who are already developed
- may show a more negative body image, follow an unsafe diet, and start exercising
- seek out older friends, leading to increased likelihood of dating, smoking, drinking, sex, and petty crime
- more likely to have depression
late-developing girls
these girls experience anxiety while waiting to become adults
- in contrast to late-developing boys, they do very well in school
scaffolding theory of aging and compensation
explains how the brain copes with the loss of brain function
- the brain of older people selects other brain regions to help
premenstrual syndrome
abdominal bloating, headaches, bad mood, and sore breasts just before menstruation starts
premenstrual dysphoria syndrome
includes affective symptoms, so it affects the quality of relationships
- caused by an imbalance of oestrogen and progesterone
- treatment may include taking vitamins and minerals, or antidepressants
menopause
the end of menstrual periods, typically between ages 45-54
hormone replacement therapy
used to suppress the symptoms of menopause
andropause
a slow decline in testosterone, accompanied by low libido, dizziness, lack of energy, memory problems, erectile dysfunction, and loss of pubic hair
- by age 80, men only have 20-50% of the testosterone of a 20 year old
prenatal phases
- germinal phase
- embryonic phase
- foetal phase
germinal phase
- week 0-2
- the cell mass (zygote) divides and moves via the fallopian tube towards the uterus
- the cell mass develops into a blastocyte and nests in the uterine wall
- this is a very sensitive phase and many miscarriages occur here
embryonic phase
- weeks 3-8
- the blastocyte consists of three layers, the endoderm (evolves into the digestive and respiratory system), the mesoderm (later muscular and skeletal system), the ectoderm (later skin and nervous system)
- the baby connects to the mother’s bloodstream, which allows for the first heartbeat in the 3rd week of pregnancy and facilitates growth
foetal phase
- week 9-40
- a slower period of refinement in which body structures emerge
- the brain increases in size (doubles from month 4 to 7) and brain folds are formed
- hearing develops
- neuronal development proceeds in a sequential order
order of neuronal development
- neurulation: formation of the neural tube
- neuronal proliferation: rapid formation of neurons
- neural migration: neurons move to their final place in the brain
three principles of prenatal development
- proximodistal order: from inside to outside (arms to fingers)
- cephalocaudal order: from top to bottom (head to legs)
- from a mass to specific: from undifferentiated to differentiated (simple to sophisticated)
teratogens
harmful influences on the unborn child
- most harmful in the embryonic phase
- how harmful it is depends on individual differences and the dose of teratogens
foetal alcohol syndrome
characterized by a flat face, low weight, growth retardation, and damaged brain
- children with FAS have a different brain strucutre, a mental disability, and/or cognitive problems
sensation
the product of the interaction of information from all sensory receptors (senses)
perception
the interpretation of sensory information
babies and language
- after 1 month, babies pay attention to speech
- after 5 months, babies are sensitive to syllables of their mother tongue
- after 6-8 months, babies are able to filter out sounds that do not belong to their mother tongue
hearing and old age
hearing declines due to physiological changes in the ear
- decrease in hair cells and collapsed ear canal
- men experience hearing loss more rapidly than women
newborns smell and taste
- preference for the smell of mother’s milk and amniotic fluid
- the smell is reassuring and reduces crying
adolescents smell and taste
- experimentation with tastes they previously disliked
- influenced by cognitions and chemosensory irritations
- girls have a higher sensitivity to taste than boys due to hormonal differences
elderly smell and taste
- sensitivity to taste decreases with age, especially in men
- also decline in sense of smell (only pleasant smells can be noticed more poorly, can lead to less pleasure when eating)
foetus and newborns sight
a foetus can already react to bright light, but there is low visual accomodation
- newborns have preference for high contrast and patterns, color vision, and shape perception from 3 months onward
- around 2-3 months babies can recognize a face
- at 8 months fear bias occurs: hypersensitivity to fearful facial expressions
- at 9 months, babies become less sensitive to faces of people from other ethnic backgrounds
- around 1 year children have the same vision as adults
visual cliff paradigm
can be used to examine depth perception in babies
- at 6-7 months old a baby reacts anxiously to the deep side of the visual cliff
baby motor skills
- around 1 year, babies start to walk (large individual differences)
- stimulates the child’s cognitive development
