Plasticity Flashcards
Plasticity
refers to the way in which the brain’s neural structure or function changes in response to environmental stimuli. Although changes to the brain occur more frequently in the foetal stage and in babies, children and adolescents, they continue throughout life as learning takes place. Note that developmental plasticity occurs alongside adaptive plasticity.
Developmental plasticity
the ability of the synapses in the brain to be modified during its growth and development (where the neurons are quite flexible in terms of their function) either though the process of strengthening neural connections or eliminating unused neural connections.
DP - Proliferation
the process whereby the unborn baby’s cells that will become neurons divide and multiply, creating approximately 250 000 cells per minute.
DP - migration
newly formed neurons move outward to their destined location
DP - circuit formation
the axons of new neurons grow out to target cells and form synapses with them (e.g. axons of motor neurons grow to the spinal cord where synapses are formed with other neurons on this location).
DP - Circuit - synpatic pruning
elimination of excess neurons and synapses, that is, those that have not established a connection with a target cell die. During this process, synapses may be strengthened or weakened in accordance to whether their presynaptic and postsynaptic neurons fire together (if a neuron does not fire together with its neighbouring neurons, it is probably in an inappropriate area, and may be part of circuit pruning).Pruning occurs in childhood and a second phase during adolescence.
DP - myelination
the process whereby the axons of the neurons in the brain become covered in myelin (white, fatty, waxy substance) which protects the axons from electrical interference from other neurons and speeds up the rate of transmission of signals within the neuron.
· This is the final stage that needs to happen for the brain to become fully mature.
· Myelin begins at the lower structures of the brain, followed by the cerebral hemispheres: occipital lobes → temporal lobes → parietal lobes → frontal lobes ·
The prefrontal cortex is the last part of the brain to develop and is responsible for problem solving, planning, impulse control and thinking.
- occurs through childhood and adolescence and into young adulthood (age 23)
Adaptive plasticity
refers to changes in the brain’s neural structure to enable adjustment to experience, to compensate for lost function and/or to maximise remaining functions in the event of brain damage.
Ap - rerouting
when an undamaged neuron that has lost connection with an active neuron due to damage, seeks a new active neuron to connect with instead.
AP - sprouting
growth of new, bushier connections on a neuron’s dendrites.
o Both rerouting and sprouting enable the formation and growth of entirely new neural connections at the synapse to compensate for loss of function due to brain damage.
Sensitive periods
a specific time in development when an organism is more responsive to learning something than any other time in development; this occurs in humans.
Experience-expectant learning
occurs during sensitive periods and refers to experiences necessary for learning to occur (e.g. for children learning to speak in their native tongue, if the opportunity is missed in infancy and early childhood, it is significantly more difficult to achieve fluency).
Experience-dependent learning
a form of learning that can occur at any time during an individual’s life (e.g. learning to read and write in one’s native tongue).
Critical periods
a very narrow period of time in an animal’s development in which the animal is pre-programmed for learning to occur; occurs in animals (e.g. young birds imprint to the first moving object they see after they hatch from the egg).
