106404
| Question | Answer |
| By how much does the brain grow after birth? | Substantially after birth |
| Why does the increase in size of brain, in most areas, not a result of development of new neurons? | All of the neurons that will compose of the adult human brain have developed by seven months of prenatal development |
| What are the three kind of growth which explains the increase in size of post-natal brain? | Synaptogenesis, myelination of axons, and increased branching of dendrites. |
| Why is there an interest in post natal synaptogenesis? | Connections between neurons in a particular region of the brain is assumed to be an indicator of analytic ability. |
| What is the rate of synaptogeneis in the cortex after birth? | An increase, but it varies between cortical regions |
| What does myelination do? | Increases the speed of axonal conuction |
| What does myelination of various areas of the human brain reflect? | The functionality development |
| What are the three general area steps of myelination? | Sensory straight after birth, then motor soon after, then prefrontal cortex until adulthood |
| In general, what does the pattern of dendrite branching copy? | Neural migration, from deeper layers to more superficial layers |
| How long does it take even mature dendrites to change their shape? | Few seconds |
| What is an example of regressive changes after birth? | Once maximum synaptic density has been reached, there are periods of synaptic loss. |
| What has been suggested to underlie the greater plasticity of the younger brain? | Overproduction of synapses |
| What have several structural MRI studies of the developing brain focused on? | Relationship between the growth of cortical gray matter and growth of cortical white matter. |
| How fast does cortical white matter grow? | Slowly and steadily until early adulthood |
| How does gray matter grow? | Large as it can then decreases in size |
| What marks the full maturation of an area, reaching functional maturity? | When gray matter levels out. |
| Out of all the brain areas, what has the most prolonged development? | Prefrontal cortex |
| What is belied to be the cause of the human cognitive development? | Development of prefrontal cortex |
| What are the four types of cogntive development linked to prefrontal cortex? | Working memory, planning and carrying out sequences of actions, inhibiting responses which are inappropriate in the current context, following rules for social behaviour. |
| How have cognitive functions been linked to the prefrontal cortex? | Children do not display them until the prefrontal cortex develops |
| What is preservation? | Tendency to continue to make a formerly correct response when it is made incorrect |
| What did Diamond (1991) hypothesize in regard to preservation? | Infants between 7-12 months did this because the neural circuitry of the pre-frontal cortex is not yet fully developed in that period |
| What evidence is there for Diamond's (1991) hypothesis? | It was demonstrated in infant monkeys and adult monkeys with bilateral lesions on the prefrontal cortex |
| What is involved in over coming perservation? | Holding information in working memory and suppressing previously correct and now incorrect answer |
| When does synaptogeneis in prefrontal cortex become maximal? | Early Second year |
| What does experience have in early development? | On maintenance and reorganization of neural circuits. |
| Neurodevelopment occurs through the interaction between, what? | Neurons and their environment. |
| What is permissive experiences? | Those that are necessary for information in the genetic program to be manifested. |
| What are instructive experiences? | Those that contribute to the direction of development |
| What is an important feature of the effects of experience on development? | They are time-dependent, meaning the effect depends on when it occurs during development |
| What is a critical period? | When experience is absolutely essential within a period to influence development |
| What is a sensitive period? | When an experience has a great effect on development when it occurs during a particular interval but can still have weak effects outside the interval |
| What are most experiential effects on development? | Sensitive periods |
| What is the general principle which seems to characterize the effects of experience on development on all neural circuits? | If neural circuits, once formed, are not used, they do not survive and function normally. Use it or lose it. |
| What is the main advantage of developing slowly? | Many chances for experiences to fine-tune development |
| What are the two general manipulations of experience early research focused on? | Sensory deprivation and enrichment |
| What was found when animals were reared in the dark? | Had fewer synapses and fewer dendrite spines in their primary visual cortexes, as adults had deficits in depth and pattern vision. |
| What happens when animals are in an enriched environment? | Have thicker cortexes with more dendritic spines and synapses |
| What can depriving one eye of input for a few days in early life cause? Does the same effect occur if both eyes are covered? | Adverse effect on vision in the deprived eye, ability of that eye to activate visual cortex is reduced but increased in other eye. But if both eyes are covered, no effect. |
| What can change the pattern of synaptic input into layer 4 of the primary visual cortex? | Early monocular deprivation (covering one eye) |
| Occular dominance columns in layer 4 of the primary visual cortex is almost fully developed at birth, but what is the sensitive period of depriving an eye of light? | First few months of light. |
| Who found a structural change due to depriving an eye of light for a few days? And what was the change? | Antoini and Styker (1993),a massive decrease in axonal branching of the lateral geniculate nucleus neurons which normally carry signals from deprived eye to layer 4, of the primary visual cortex. |
| Who surgically altered the course of developing axons of ferrets' retinal ganglion cells so the axons synapsed in the medial geniculate nucleus of the auditory over visual? What was found? | Roe et al. (1996). The experience of visual input caused the auditory cortex to become retinotopically organised (normally wouldn't have) |
| Who raised barn owls with vision-displacing prisms over their eyes, and what did it cause? | Knudsen and Bainard (1991). This lead to change in the auditory spatial map in the tectum |
| What have several studies found in regard to early music training? | It influences the organization of human cortex |
| What happens long before the nervous system is fully developed? What does this result in? | Neurons begin to fire spontaneously, and to interact with the environment. Resulting pattens of neural activity fine-tune subsequent stages of neurodevelopment. |
| What does the fine-tuning constitute in development? | The last and critical stage of development |
| Why are there still gaps in the research? | Due to the fact there are so many possible mechanisms. |
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