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BRAIN AND BEHAVIOUR - localisation and plasticity - Coggle Diagram
BRAIN AND BEHAVIOUR - localisation and plasticity
Function localisation: certain areas of the brain are in charge of specific behaviours or cognitive processes.
HM STUDY
studied specific parts of the brain and their function
ie. HIPPOCAMPUS - transferring short term to long term memory
also found that: The cognitive process is the consequence of distributive processing rather than function localisation. (parts of the brain work together).
researchers are looking at the brain through mapping called connectome
4 main areas of the brain:
BRAIN STEM
regulates life functions
breathing, heart rate, blood pressure
CERBELLUM
role in balance and motor function
speech production, learning
CEREBRAL CORTEX
largest part
thought + action
CEREBRUM
divided into 4 lobes
FRONTAL LOBE - executive functions (planning, speech, decisions)
OCCIPITAL LOBE -visual processing
PARIETAL LOBE - perception of stimuli
TEMPORAL LOBE - auditory processing and memory
LIMBIC SYSTEM
emotional brain, major focus of psychological researches
5 components
AMYGDALA - formation of emotional memory + fear response
BASAL GANGLIA - habit-forming + procedural memory
HIPPOCAMPUS - transfer of short term to long term memory
HYPOTHALAMUS - homeostasis, emotion, thirst, hunger, control of nervous system, controls pituitary gland, circadian rhythms
NUCLEUS ACCUMBENS - addiction and motivation
THE CASE OF EUGENE PAULY - 1992
EUGENE PAULY - diagnosed at 70 with viral encephalitis
amygdala + hippocampus= destroyed
researcher Squire interviewed him a couple of times
Eugene was not able to draw a map of his house but knew where the toilet was
some tasks become associative tasks (automatic) instead of remaining cognitive
for example, on the road home, if perhaps he had to leave his habitual path, he would get lost. His memory was only procedural
OBSERVATIONAL STUDIES, INTERVIEWS, MRIs
basal ganglia - procedural memory (In fact it wasn't damaged)
BRAIN PLASTICITY
brain is sculpted by experience
brain is constantly changing as a result of experience
plasticity: ability of the brain to alter its structure following changes with body or environment
Brain's ability to rearrange connections between neurons
all results of learning experience
every time we learn something new, neurons connect to create a trace in the brain called DENDRITIC BRANCHING
ROSENZWEIG, BENNETT AND DIAMOND (1972)
evaluate the effect of enrichment or deprivation on neuron growth in the cerebral cortex through lab rats
enriched environment: more than one rat in each cage, presence of stimulus objects for the rats to play with and maze training
deprived environment: rat was alone with no stimulation
The rats were placed in their separate habitats for 30 or 60 days before being killed in order to assess the influence of the environment on their brain structures.
results: enriched environment increased cortex thickness because of more dendritic branching
IMPORTANCE OF STIMULATION AND EDUCATION IN THE GROWTH OF NEW SYNAPSES
MAGUIRE ET AL (2000)
aim:
See whether the brains of London cab drivers vary in any way as a result of their remarkable knowledge of the city and the many hours they spend behind the wheel navigating
sample:
16 right handed male London taxi drivers (range of age)
MRI scans were done comparing their brain to normal non taxi driver males in London
correlational study where the researchers were expecting to see a relationship between the number of years of driving a taxi and the anatomy of one's brain
findings:
Taxi drivers' posterior hippocampi were substantially bigger than control participants', whereas their anterior hippocampi were much smaller.
findings 2:
The volume of the right posterior hippocampi was proportional to the amount of time spent driving a cab.
SYNAPTIC PLASTICITY
synapses become stronger through repeated use (long term potentiation)
when synapses is not used or under-stimulated -
synaptic pruning
- way for the brain to remove synapses that are no longer needed
NEUROTRANSMISSION
neurons - one of the building blocks of behaviour
neurons send electrochemical messages to the brain so that people can respond to stimuli
An
action potential
is an electrical impulse that passes along the body of a neuron.
When an action potential travels down the neuron's body, or
axon
, it releases neurotransmitters that are held in the
terminal buttons
of the neuron.
The neurotransmitters are subsequently released into the
synapse
, which is the space between neurons.
The neurotransmitters, like a key in a lock, fit into
receptor sites
on the post-synaptic membrane after crossing the synapse.
Once the message has been transmitted, the neurotransmitters are either degraded by an enzyme or reabsorbed by the terminal buttons in a process known as reuptake.