Neural basis of learning
• areas of the brain and neural pathways
involved in learning, synapse formation, role of
neurotransmitters
• developmental plasticity and adaptive plasticity
of the brain: changes to the brain in response
to learning and experience; timing of
experiences
Neural basis of learning
 Neurons are soft, flexible living cells
 They can change their size, shape, function and connections
with other neurons throughout our lifespan
 Influenced by interaction between biological influences and
experiences in everyday life
 Synapse – includes the synaptic gap, presynaptic neuron
and postsynaptic neuron
Neurons and learning
 When learning occurs changes take place at the synapse
 Learning involves establishing and strengthening of neural
connections at the synapse
 Groups of neurons form pathways (networks) for the learned
information
 Some pathways overlap, means more than one pathway may be
involved in different learning
 More a pathway is used, stronger the neural connections
and the more efficient the transfer of information. The less
a pathway is used, it can weaken and become less efficient
in transmitting information
Neurons and learning
 Neurotransmitters can excite a postsynaptic neuron (making
more likely to fire) or inhibit (making it less likely to fire)
 Neurotransmitters are chemical substances that carry
information between neurons
 Glutamate: strengthens connections at the synapse during
learning
 Dopamine: communicates activities which may be rewarding
though ‘pleasure’ experiences
 Acetylcholine (Ach) present in some learning but role is
unclear
Neurons and learning
Synaptic changes caused by
learning are believed to have
long-term potentiation
 LTP The long-lasting strengthening of synaptic connections
resulting in the enhanced functioning of neurons along a
neural pathway whenever activated
 LTP is a crucial mechanism of learning, learning may not
be possible without it
LTP and learning
 Morris et al. (1982) – Rats and a water maze
Group 1
Damaged cerebral cortex in
 Role of the hippocampus inthe
spatial
upperlearning
frontal lobe
Group 2
Damaged hippocampus
Group 3
‘normal’ rat, no damage
 http://www.youtube.com/watch?v=_uco9kTr_jI
 http://www.youtube.com/watch?v=LrCzSIbvSN4
Plasticity – the ability for the brain
to change through experience
 Plasticity – ability of the brain’s neural structure or function to
be changed by experience throughout the lifespan
 Flexible
 Lifelong Plasticity (learning experiences throughout our life)
 Genes are the ‘architect’, our experience guides, sustains
and maintains us.
 Developing brain is more plastic (flexible) than the adult brain
 Brain can be altered by learning and experience
Plasticity experiments
 Evidence the brain is altered by learning and experience
Rosenzweig et. al. (1960s) Lab rats
3 conditions (80 days)
1 – standard lab cage
2 – ‘impoverished’ (deprived environment)
3 – ‘enriched’ environment
Findings of enrichment and impoverishment studies
‘enriched’ rats
 had a thicker and heavier cerebral cortex
 Bushier dendrites
 Existing synapses were bigger
 New synapses were formed
Findings of impoverishment and enrichment studies on people
University students 40% more synaptic connections than
people who do not complete high school
Enrichment activities in old age reduces the risk of cognitive
decline in old age
Developmental plasticity
(maturation)
 Brain’s natural ability to form new connections in order to
process sensory information from the environment.
 It is the neural changes which occur to the brain due to
experience during maturation (growth and development). It
has a genetic base but is influenced by experience
 Child’s brain has greater plasticity than an adults brain
 Developmental plasticity decreases with age
Developmental Plasticity
(maturation)
Synaptogenesis – process of forming new synapses
Synaptic pruning – process of eliminating synaptic
connections
occurs in different areas of the brain at different times.
visual cortex finished by age 10
frontal lobe age 14
Adults have 40% less than a 3yr old
Experience determines which synapses will be pruned or
strengthened.
Developmental Plasticity
(maturation)
Timing of the brain
Sensitive period period of time when we are more sensitive to
certain environmental cues
(language acquisition, eye – connect to visual cortex).
Sensitive periods suggests there are times when some synaptic
connections are more easily made and neural pathways are more
easily formed – but need exposure to the environment
Experience-expectant process – brain is genetically primed, or
getting ready, for experiences that are expected at a particular
time (during a sensitive period)
Adaptive Plasticity
(Think of it as the brain trying to adjust to compensate, the
brain is trying to adapt)
 Adaptive Plasticity is the brain’s ability to form new
connections in order to recover or compensate for lost
function and or to maximise remaining functions in the event
of brain injury
 Occurs to a greater extend in infancy and early childhood
Adaptive Plasticity
Neural rerouting
Undamaged neuron lost connection with an active neuron, may
seek a new active neuron and connect with it instead.
Sprouting growth of new bushier nerve fibres with more
branches to make new connections
 To form new connections, need to be stimulated through
activity.
Examples of people where function of one hemisphere is taken
over by the other hemisphere