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The brain and behavior - Coggle Diagram
The brain and behavior
Localisation and plasticity
Localisation of function
Localisation of function: theory that specific parts of the brain are responsible for specific behaviours or cognitive process
Researchers; attempting to map brain by looking at neural connection and creating a map called a
connectome
Brain stem
Responsible for regulating life functions; breathing, heart rate, blood pressure.
Cerebellum
Key role in balance and motor function (speech production) and learning (conditioned responses )
Cerebral cortex; largest part of brain, associated with higher brain function e.g thought and action
Cerebrum
Occipital lobe
visual processing
Parietal lobe
perception of stimuli
Frontal lobe
Executive function - planning, decision making
Temporal lobe
auditory processing and memory
Limbic system
the "emotional brain" - role in memory and emotion - studied in psychology
Hippocampus
transfer of short term memory to long-term memory
Hypothalamus
homeostasis, emotion, thirst, hunger, circadian rhythms and control of the autonomic nervous system, and control of pituitary gland
Basal ganglia
habit-forming and procedural memory
Nucleus accumbens
addiction and motivation
Amygdala
formation of emotional memory and fear responses
Although some parts of brain play specific roles in behavior; rarely does part of the brain work in complete isolation
The case of Eugene Pauly (Larry Squire - 1922)
Pauly diagnosed with viral encephalitis - amygdala and hippocampus destroyed
Squired carried out interviews at his home, not able to draw a map of home when asked; EP then excused himself to go to the bathroom (couldn't map house but could find toilet on his own?)
tasks that rely on procedural memories make this transition from involving an active frontal lobe to an active basil ganglia - cognitive process
Brains adapt to minimise amount of energy when doing something new - overtime, task is no longer cognitive, but
associative task
- when task becomes automatic (habit )
if everyday habits had been blocked by any obstacle for EP, the associative task would switch to cognitive and he wouldn't remember how to do them (his memory became only procedural)
Interviews, IQ testing, observational studies, MRIs to determine extent of damage to EP's brain
Basal Ganglia = undamaged; rsponsible for procedural memory
Brain plasticity
Plasticity refers to brain's ability to alter its own structure (rearrange connections between neurons) following changes within the body or in the external environment
High levels of stimulation and numerous learning opportunities lead to an increase in density of neural connections
Denditric branching: dendrites of neurons grow in numbers and connect with other neurons
Rosenzweig, Bennett, and Diamond (1972)
placed 2 rats in 1 environment to measure effect of enrichment or deprivation on development of neurons in cerebral cortex
Enriched: rats placed in cages with up to 11 other rats, maze training, and stimulus objects
Deprived: rat was alone and no stimulation
Post mortem studies: those who had been in enriched had increased thickness in cortex as result of dendritic branching, frontal lobe was heavier
Maguire et al (2000)
Aim: see wether brains of London taxi drivers were different as a result of their exceptional knowledge of the city and the hours they spend behind wheel
Mental map of the city of London
Sample: 16 right handed male London taxi drivers of random age
Control group: 50 right handed males non taxi drivers
Procedure: MRI scan of brains and compared to MRI scans of non-taxi drivers
To take part in study, you had to complete "knowledge test" and their licence had to be at least 1.5 years old
Evaluation: correlational study (numbers of years of taxi driving and anatomy of the brain) + single-blind study (researcher did not know wether she was looking at scan of driver or control)
Results: 1. posterior hippocampi of drivers were significantly larger compared to the control, and anterior hippocampi were smaller
volume of right posterior hippocampi correlated with amount of time spent as driver
Maguire argued that this demonstrated that the hippocampus may change in response to environmental demands
Synaptic plasticity
Synapses become stronger through repeated use = LONG-TERM POTENTATION, leads to a greater level of responses and longer periods of depolarisation of the post-synaptic membrane. Over time, this leads to protein synthesis and gene expression which bring to dendritic branching = NEURAL ARBORIZATION
When synapse is not used or under-stimulated = SYNAPTIC PRUNING, brains way of removing synapses no longer useful to make neural network more efficient
Bremner (2003)
study of localisation and plasticity very much linked
Aim: long-term stress appears to lead to hippocampal atrophy (hippocampal cell death)
Sample: 33 women (10 with early childhood sexual abuse and PTSD, 12 with abuse without PTSD, and 11 without abuse or PTSD)
Procedure: used an MRI scan to measure volume of the hippocampus in all participants and PET scan to measure its level of function during during a verbal declarative memory test
Result: women who were abused and PTSD showed 16% smaller volume of hippocampus compared to women with abuse and without PTSD. these women showed lack of activity in hippocampus when carrying out memory task
Women with abuse and PTSD had a 19% smaller hippocampal volume compared to women without abuse or PTSD