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UNIT 4
BRAIN, BEHAVIOUR &
EXPERIENCE
LEARNING
Neural processes involved in learning
NEURAL PROCESSES INVOLVED IN
LEARNING
• Neurons are soft, flexible, living cells
• They can change their size, shape, function and connections with
other neurons
• They are influenced by biological processes and environmental
experiences
DEVELOPMENT OF NEURAL PATHWAYS
When learning
occurs, physical
changes take place in
the brain at a
neuronal level
• The most prominent change is at the synapse
• Learning changes the strength of connections between neurons at the
synapse
• Learning can cause new synapses to form
• Neurotransmitter forms the basis of these connections
DEVELOPMENT OF NEURAL PATHWAYS
ROLE OF SYNAPSES
DONALD HELB (1949)
‘Neurons that fire together, wire together’
•Credited with the idea that learning involves the establishment and
strengthening of neural connections at the synapse
•Learning results in the creation of ‘cell assemblies’ (interconnected groups of
neurons that form networks or pathways)
• When neurotransmitter is repeatedly sent
across the synaptic gap, the pre-synaptic
neuron and the post-synaptic neuron are
repeatedly activated at the same time
• This changes the chemistry of the synapse,
strengthening the connections between
neurons
• This makes them more likely to fire
together again
DEVELOPMENT OF NEURAL PATHWAYS
LONG-TERM POTENTIATION
DONALD HELB (1949)
‘Neurons that fire together, wire together’
•These synaptic changes that occur in a neural pathway during learning are
believed to have long-term potentiation
•Repeated stimulation causes a post-synaptic neuron to be more responsive to
the pre-synaptic neuron
•LTP makes learning possible in humans and all animals with nervous systems
•The exact role of LTP is yet to be extensively investigated
DEVELOPMENT OF NEURAL PATHWAYS
NEUROTRANSMITTERS INVOLVED IN
LEARNING
GLUTAMATE
• Has a crucial role in learning
• Glutamate initiates activity in post-synaptic neurons
• Its repeated release is believed to contribute to synaptic formation and strengthen
connections at the synapse during learning
DOPAMINE
• Contributes to the strengthening of synaptic connections during learning
• Has been researched for its role in reward-based learning
• When you do something you like, dopamine is secreted within a specific neural
pathway in the brain
• The release of dopamine provides a pleasurable experience
• This motivates the individual to repeat the behaviour
PLASTICITY & EFFECTS OF EXPERIENCE
ON THE BRAIN
Plasticity is the ability of the brain’s neural structure or function to be changed by
experience throughout the lifespan
Our genes govern the overall architecture of our brain, but experience guides, sustains and
maintains the details
The brain of a developing individual is more plastic than an adult
(i) DEVELOPMENTAL PLASTICITY
(ii) ADAPTIVE PLASTICITY
PLASTICITY & EFFECTS OF EXPERIENCE ON
THE BRAIN
DEVELOPMENTAL PLASTICITY
Developmental plasticity refers to changes in the brain’s neural
structure in response to experience during its growth and
development
•This type of plasticity is pre-determined and influenced by genes, but subject to
experience
•Forming new synapses = synaptogenesis
•Occurs rapidly during the first year of life
•Eliminating synaptic connections = synaptic pruning
•Number of synapses in an adult is 40% less than the number of synapses in a
three year old
PLASTICITY & EFFECTS OF EXPERIENCE ON
THE BRAIN
ADAPTIVE PLASTICITY
Adaptive plasticity refers to changes occurring 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
•Most evident when the brain has experienced damage through either inflicted or acquired
injury through re-organising the structure of the brain
•The way that the brain responds depends upon the location, degree and extent of the
damage, and the age at which the damage is experienced
•Can be done at neuronal level, larger areas of brain tissue or at hemispheric level
•Rerouting = an undamaged neuron that has lost a connection with an active neuron may
seek a new active neuron and connect with it instead
•Sprouting = the growth of new bushier nerve fibres with more branches to make new
connections. Sprouting also involves rerouting
PLASTICITY & EFFECTS OF EXPERIENCE ON
THE BRAIN
TIMING OF EXPERIENCES
PLASTICITY & EFFECTS OF EXPERIENCE ON
THE BRAIN
TIMING OF EXPERIENCES
Sensitive Periods of Development
A period of development when an organism is more responsive (or sensitive)
to certain environmental stimuli or experiences
‘Windows of opportunity for learning’
They are the optimal, or best possible, times for relevant learning to occur
EXPERIENCE-EXPECTANT LEARNING
=
the brain encounters the experience that is
expected, ideally in a sensitive period. The
particular experience then contributes to
the brain’s development. Occurs at infancy
EXPERIENCE-DEPENDENT LEARNING
=
Learning that ‘depends’ on exposure to
specific ‘experience’. Occurs at any time
during an individual’s development
PLASTICITY & EFFECTS OF EXPERIENCE ON
THE BRAIN
TIMING OF EXPERIENCES
Critical Periods of Development
A specific period of development during which an organism is most
vulnerable to the deprivation or absence of certain environmental stimuli
or experience
• Have identifiable start and end times
• For example, if after birth, one eye is kept closed, or does not function properly, the eye
will be forever blind
• Imprinting is an example of a critical period (a period when an attachment is formed
directly after birth)