Brain Development Flashcards
Describe structure and role of the visual cortex
- area of cerebral cortex, found at the back of the brain
- receives and processes visual info
Describe how visual cortex receives visual information
- neurones in visual cortex receive info from either left or right eye
- neurones are grouped in ocular dominance columns; columns of same size arranged in an alternating pattern (L,R,L,R…)
Outline Hubel and Wiesel’s experiment into visual development
- carried out research on animals with similar brain structure to humans
~ stitched kittens eye closed soon after birth
~ after 3 months, found kittens were blind in stitched eye
~ looked at neurone activity in visual cortex, found ocular dominance columns corresponding to stitched eye were smaller than normal while those corresponding to open eye were larger than normal - repeated this with adult cats —> no blindness occurred + no changes in distribution of ODCs
What did Hubel and Wiesel conclude from their research?
Without early stimulation, ODCs are unable to develop normally
Define critical period
A period in early development where synapses between neurones are strengthened, must occur for proper development
Describe role of visual stimulation during critical period
- soon after birth neurones begin to form connections —> neurones
- both eyes must be visually stimulated for neurones in VC to be correctly organised
- synapses which pass on nerve impulses are strengthened and become permanent part of the visual cortex
- those that do not are lost + cannot be reformed
Give ethical argument for use of animals in research
• new drugs must be tested on whole organism, not group of cells
• more ethical than using humans, testing drugs we don’t know are safe on humans is unethical
• only carried out on animals when no alternatives, governed by strict regulations
• animal anatomy is similar to humans so research is transferable
Give ethical argument against use of animals in research
• testing in human cells/tissue or computer models provides an alternative
• many believe animals should have same rights as humans -consent, welfare
• animals still suffer pain and distress despite regulations, may be killed to analyse tissues
• animal and human anatomy ≠ identical, medications may have a different effect on humans than on animals
Why is it difficult to determine whether nature or nurture has a greater influence?
Genes and environment interact; investigating one factor would mean completely removing the other which is almost impossible
Describe how animal experiments can investigate effects of nature and nurture
Animal experiments —> manipulate environment to investugate impact in brain development on animals of the same species (same genes so more likely due to environmental changes)
Describe how genetic modification can investigate effects of nature and nurture
Can be used to switch off function of certain genes + raise genetically modified animals alongside unaltered in same environment —> allows sole impact of genetic factors to be looked at
- considered ethical in less complex animals e.g. mice but not humans
Describe how cross-cultural studies can investigate effects of nature and nurture
Different cultures = different environmental influences on brain development, so can compare children of same age from different backgrounds –> differences = nurture, similarities = nature
Describe how twin studies can investigate effects of nature and nurture
Identical twins genetically identical so if raised in different environments any differences in brain development are due to nurture whilst similarities would be nature
- twins raised together often share a very similar environment so difficult to separate nature + nurture —> not identical twins can be used as a control group, so differences between identical and non identical are likely due to nature
Describe how newborn studies can investigate effects of nature and nurture
Environment outside womb has little impact on brain development in newborn babies —> level of brain development babies are born with likely due to nature not nurture
Describe how brain damage studies can investigate effects of nature and nurture
Looking at brain damage in children can help study effects of brain damage on development as childrens brains are still developing —> may look at specific traits and compare development in children born with and without brain damage
- if children born with brain damage show development of a characteristics, likely due to nurture and vice versa
