Transcript Learning - Dot Point 2.

Learning - Dot Point 2.
Part A.
Learning and Changes in
the Brain – Brain Structures
Associated with Learning
Key Knowledge:
Mechanisms 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
• Use of imaging technologies in identification of
localised changes in the brain due to learning
specific tasks.
(VCE Study Design, 2009)
Areas of the brain and neural pathways involved in
learning, synapse formation, role of neurotransmitters
Brain structures involved in
learning
• Limbic System
– Hippocampus
– Amygdala
•
Cerebral cortex
– Basal Ganglia
•
Cerebellum
• Midbrain
– Ventral tegmental area
The Limbic System
• The limbic system is composed of
a number of structures that form
a doughnut-shaped neural
system between the hindbrain
and the cerebral hemispheres.
• Key structures under
consideration:
– Hippocampus
– Amygdala
Hippocampus
• The hippocampus plays a central role in the mechanism of learning.
– Learning new information which will become declarative memory
typically involves an interaction between the hippocampus and
relevant areas of the cerebral cortex which specialise in storing
declarative-type information, such as the occipital lobe for visual
memory of written words.
• Higher-order animals and humans who have damage to both their
left and right hippocampi are able to feel the emotion of fear when
they experience pain from a stimulus (for example, an electric
shock).
• However, they are unable to learn or remember to be fearful the
next time they experience a situation in which they will receive the
electric shock again.
Hippocampus cont.
• The hippocampus is involved in learning how
to navigate through space.
• It is crucial to the formation and storage of
episodic memories and it has also been
identified as a site for a variety of declarative
learning and memory functions.
Amygdala
• The amygdala has a role in
emotional learning—in learning
to associate fear with a new
unpleasant stimulus.
• Stimulation of the amygdala
activates the hippocampus and,
in humans, learning and memory
for pleasant and unpleasant
emotional information is linked to
the amount of activity in the
amygdala when the learning
occurs.
• In humans and other animals, the
amygdala’s main function is to aid
survival behaviour, particularly
related to aggression and fear
(fight–flight).
– The amygdala provides a
primitive ‘quick pathway’ to
the cortex, which enables us
to react to dangerous stimuli
before we have fully
comprehended the situation.
Amygdala cont.
• When the amygdala is stimulated, animals will respond
with aggression or rage
• Application: Humans with damage to their
amygdala are unable to be classically conditioned
(to learn) to fear a dangerous object (stimulus).
– This has been shown experimentally with patients.
Even if they knew that every time a bell sounds they
will receive a shock (Burton et al. 2009) they held no
fear.
– The amygdala plays a role in a person’s learning to
fear bees but if they have damage to their
amygdala, they will show no fear towards the bee.
Cerebral Cortex – Basal Ganglia
• The Basal ganglia is found in the frontal
lobes.
– It uses information from the primary and
secondary motor areas of the frontal lobes,
as well as from the somatosensory cortex, to
integrate and smooth bodily movements.
– Neural Pathways are transferred to the Basal
Ganglia and new neural activity is generally
activated once a response becomes very well
learned and no longer requires much
conscious thought.
• People who suffer from diseases which
damage the basal ganglia, such as
Parkinson’s or Huntington’s disease, have
great difficulty learning to do tasks which
result in non-declarative memory, such as
learning skills which result in procedural
memory.
Cerebellum – ‘little brain’
• The cerebellum is located in the
hindbrain and plays a role in the
order of muscular movement,
balance and posture.
• It is also necessary for learning
motor skills, as well as contributing
to non-motor learning.
• The cerebellum is also implicated in
neural circuits involved in simple
stimulus–response learning
(classical conditioning)
• The cerebellum and basal ganglia
work together in learning movement
sequences so that the movements
can be carried out together.
Midbrain Structure:
Ventral Tegmental Area
• The ventral tegmental
area (VTA) is located in
the midbrain
• It is thought to have a
role in learning through
operant conditioning.
– In particular, it plays a
role in the rewarding
effects of primary
reinforcers in operant
conditioning, for
example food or
reproduction.
Brain development during adolescence
• During adolescence in humans, a large amount of development occurs
in structures of the brain that have a role in learning:
– cerebellum: there is an increase in the number of neurons and synapses
in the cerebellum, the part of the brain responsible for balance, muscle
tone, and the performance of motor skills
– amygdala: the amygdala becomes more active in adolescence
– corpus callosum: the corpus callosum thickens and there is an increase in
the number of connections between the two hemispheres
– frontal lobe, including prefrontal cortex: motor movement and higher
order thinking.
Putting it all together
Brain region
Type of learning
Neurotransmitters
Association areas of the cerebral
Recognising sensory stimuli
n/a
cortex
Neural pathways between the sensory Behavioural responses to environmental stimuli
n/a
association areas of the cerebral cortex
and the areas around the motor cortex
in the frontal lobe
Amygdala
Learning an emotional response or the
dopamine
consequence of a behaviour
Hippocampus
Learning an association between a stimulus and
glutamate
response
Basal ganglia
Well-learned responses, behaviours that require
little conscious thought
n/a
Next Time in Psych 4: Learning
• Synapse formation,
• The role of neurotransmitters in learning