Week 4 Lecture 4 - the developing brain Flashcards
What is nature vs. nurture?
the extent to which cognition and behaviour can be attributed to genes or environment
What is nature?
genetic blueprint (things we are born with
What is nurture?
role of experience
How was Piaget the middle ground of nature vs. nurture?
- Piaget considered development as a cyclical process of interactions between the child and their environment leading to a progression through stages
- Genetic contribution = developing a brain that is ready to learn in certain ways
- Environment = assimilating evidence via experience and then developing new
mechanisms in light of the feedback obtained.
What is neuroconstructivism?
- modern approach
- Interaction between environment and genetic factors
- Cognitive system matures and transforms as the brain goes through developmental changes
True or false
Human brains are very similar, but experiences are very different
True
What is the blueprint analogy?
- each connection in the brain is pre-determined
- however there are too many neurons and synapses for this to be realistic
What did Gottlieb propose for the structural development of the brain?
- Deterministic development – structure is the same for everyone
- Probabilistic development – each stage influence each other
What are some key features of prenatal brain development?
- Cell division
- Cell specialization
- Neural tube formation
o Proliferative zones: neurons and glial cells are produced
o During early development 250,000 neurons are produced per minute
o Neurons migrate to their final location
In prenatal brain development, many structural features of the brain emerge from other constraints
Describe these
- Folded cortex emerges from having lots of neurons
- Pattern of gyri/sulci pulled into shape by tension of axon bundles (white matter tracts)
- Hebbian learning: Spontaneous electrical activity enables networks to form (e.g. electric activity from the retina helps to form the visual pathways)
When do the majority of neurons form?
prior to birth
How much does a newborns brain weigh?
450g
Postnatal, the brain increased in size.
In what ways does this happen?
- Synaptogenesis
- Myelination
- Glial cell proliferation
What is plasticity?
-experience dependent change in neural
functioning.
- experience alone can lead to small but observable structural changes (e.g. juggling, driving a taxi
What can an increase in grey matter lead to?
- new synapses, dendrites, axon
collaterals, glia cells - but doesn’t mean better cognitive ability
What is functional brain plasticity?
prenatal brain damage can lead to major
reorganisation of tracts
What is an example of functional brain plasticity?
Patient AH –> had no right hemisphere
What are some limits of functional brain plasticity?
- Spontaneous electrical activity enables networks to form intrauterine – these
connections won’t be fully lost - Opportunities for major reorganization are time-limited = critical or sensitive periods
What did Konrad Lorenz study?
studied how birds recognize their mother
What is Filial imprinting?
- the process by which young animals learn to recognize the parent
- Happens between 15h – 3 days
- Movement is crucial
What are the 2 main features of critical and sensitive periods in imprinting?
- Learning takes place within a limited window
- But opportunity can be extended in lack of experience - This learning is hard to reverse by later experiences
- But chicks imprinted to one object can generalize to similar objects (colour or shape)
- Preference can be changed after sensitive period
What are 2 possible explanations for critical and sensitive periods?
- Genetically programmed synaptogenesis (readies brain for learning), followed by reduced plasticity (learned information is then “fossilized”)
- Closure of window could be initiated by learning itself, i.e. an environmental cue
- E.g. particular gene plays a role in filial imprinting, it is switched off after exposure
What is the empiricist vs. nativist view of innate knowledge?
- Empiricism: newborn mind is a blank state
- Nativist: we are born with some knowledge
What is a more modern view of innate knowledge?
Innate = readiness to learn (e.g. imprinting)
Knowledge or behaviour that arises in the absence of appropriate experience:
- Development of cat visual cortex
- Preferences – sweet taste, visual pattern
