Biopsychology Flashcards
What type of theory came before Localisation of Function?
A Holistic Theory
What does the holistic theory (of the brain) say?
The whole brain works together and all parts are involved in the processing of thoughts and action
What happened to switch from the holistic theory to the localisation theory?
Phineas Gage - a railway worker - was injured by a metal pole in his left frontal lobe and survived
He had personality changes but was still alive, suggesting the brain doesn’t operate as a whole or he would have died
There was a Paradigm Shift which introduced the localisation of function theory
What is Localisation of Function?
The idea that particular areas of the brain perform different tasks and are associated with different functions and parts of the body
How can we test if Localisation of Function is correct?
All damage to specific areas of the brain should result in the same problems to specific functions
What is Hemispheric Lateralisation?
The idea that the brain is divided into 2 hemispheres, and each side controls or dominates physical and psychological functions
Which side of the body does the right hemisphere control?
The left side of the body
Which side of the body does the left hemisphere control?
The right side of the body
What is the main part of the brain called?
The Cerebrum
How many hemispheres is the Cerebrum split into?
2
What is the outer layer of both hemispheres called?
The Cerebral Cortex
What are the parts of the brain (going round clockwise)?
Broca’s Area
Motor Cortex
Somatosensory Centre
Visual Cortex
Wernicke’s Area
Auditory Centre
What are the 4 physical areas of the brain (going round clockwise)?
Frontal lobe
Parietal lobe
Occipital lobe
Temporal lobe
What is in the Frontal Lobe?
Broca’s area
Motor cortex
What is in the Parietal Lobe?
Somatosensory centre
What is in the Occipital Lobe?
Visual cortex
What is in the Temporal Lobe?
Wernicke’s area
Auditory centre
What does the Motor Cortex do?
Generates voluntary bodily movement
Each hemisphere is responsible for the movement of the opposite side of the body
What happens when the Motor Cortex is damaged?
There is a loss of control of fine movements on the opposite side of the body to the damage
What does the Visual Cortex do?
Processes images and visual information
How does information get processed by the Visual Cortex?
The optic nerve is at the back of the brain and it travels from the eyes at the front to the back, crossing over, so each side of the visual cortex is responsible for the other eye’s visual field.
What happens when the Visual Cortex is damaged?
There is a loss of vision or difficulty processing visual information
What does the Auditory Centre do?
Recognises sounds and analyses speech-based information
What happens when the Auditory Centre is damaged?
There is difficulty processing auditory information
What does the Somatosensory Area do?
Sensory information from the skin is represented
It receives information such as touch, pressure, pain and heat/temperature
What happens when the Somatosensory Area is damaged?
Senses are not processed normally
What are the 2 language centres of the brain?
Broca’s area and Wernicke’s area
What side of the brain are the language centres?
Left
What language centre is Broca’s area?
Language Production Centre
What did Broca do/find?
He was a surgeon who studied patients who could understand language but not produce it (could not speak or write)
In their Post-Mortems, he found they all had damage to the same area in the left frontal lobe - Broca’s area
What happens when Broca’s area is damaged?
Broca’s Aphasia
What is Broca’s Aphasia?
Damage to Broca’s area means speech production is slower, more difficult, and takes more effort
What language centre is Wernicke’s area?
Language Understanding Centre
What did Wernicke do/find?
He studied patients who could speak but not understand or attach meaning to language
Their speech was fluent but did not make sense
He found they all had damage to the posterior portion of their left temporal lobe - Wernicke’s area
What happens when Wernicke’s area is damaged?
Wernicke’s Aphasia
What is Wernicke’s Aphasia?
Damage to Wernicke’s area means people can speak and produce language easily but it is meaningless as they cannot associate language with meaning
Evaluate Localisation of Function
Good - Brain Scan Evidence supports localisation of everyday brain functions
- Brain scans show Wernicke’s area is active in listening tasks and Broca’s area is active in reading tasks
In Addition…
- Long Term Memory studies show semantic and episodic memories are in different areas of the prefrontal cortex
- These give scientific, controlled evidence for localisation of the brain
HOWEVER
Bad - Artificial tasks were used for all of these scan studies
- This could mean they lack mundane realism and should not be used to formulate general laws of function of the brain
- Brains might be different in real life situations
Bad - Language may not be localised just to Broca and Wernicke’s areas
- 2% of modern researchers believe language in the brain is completely controlled by Broca and Wernicke’s areas
- Advances in brain imaging techniques shows language function is distributed more holistically than previously thought
- Language Streams have been identified and some include regions of the right hemisphere
- This suggests language may be more holistic than other functions
Good - Case Study support
- Phineas Gage
HOWEVER
Bad - Idiographic - brain damage is unique
What is Hemispheric Lateralisation?
The idea that the two sides of the brain aren’t alike, and brain functions are specialised to the different sides (lateralisation)
What is the left side of the brain said to be responsible for?
Language production and understanding language
Analytical Tasks
Auditory/linguistic tasks
What is the right side of the brain said to be responsible for?
Visuo-spatial tasks
Emotions
Recognition
Creative tasks
What joins the 2 hemispheres of the brain together?
A bundle of nerve fibres called the Corpus Callosum
What is the Corpus Callosum?
A bundle of nerve fibres connecting the 2 hemispheres of the brain
Which side of the body controls which?
Right controls left
Left controls right
The motor areas is cross-wired, meaning opposite control
What is the key research in hemispheric lateralisation?
Sperry’s Split Brain study
Who researched Split Brain patients?
Sperry
What makes Split Brain patients different?
They either have no corpus callosum, or it is damaged, meaning their hemispheres cannot communicate with each other
Why do people with Split Brains exist?
In the 1940s, lobotomies were performed on patients with epilepsy that cut their corpus callosums as they believed this was causing their epilepsy.
This left the patients unable to communicate across hemispheres.
(It could also be a birth defect where people are born without them, or some type of brain damage from an accident leaving them with a damaged one)
What was the procedure for Sperry’s split brain research?
- Used 11 split brain patients
- Used a controlled, special setting with screens that participants could only see half of
- The participants were shown an image or word on one side of the screen, meaning the information could only be perceived by one hemisphere
What were the findings of Sperry’s split brain research?
Saying what they saw:
- ppts could only say what they saw when they saw it in their Right Visual Field (right side of the screen)
- This is because the RVF sends information to their Left hemisphere, which is responsible for speech and language production
Drawing what they saw:
- ppts could only draw what they saw when they saw it in their Left Visual Field (left side of the screen)
- This is because the LVF sends information to their Right hemisphere which is responsible for creativity
- Not only this, but the ppts could only draw it with their Left Hand, due to the Right Hemisphere being in control of their motor production of the Left Side of the body
Describing what they touched:
- ppts could not describe an item they felt with their left hand, as the Right Hemisphere is linked to the left side, and this does not control descriptions, the Left Hemisphere does
Evaluate hemispheric lateralisation and Sperry’s split brain research
Hints:
Trees
Epilepsy
Odd one out
Good - Research support for hemispheric lateralisation
Fink
- Used brain scans to identify active areas when doing a visual task
- When they asked ppts to describe a global image such as a whole forest, the Right Hemisphere was more active
- When asked to process smaller aspects of an image such as an individual tree, the Left Hemisphere was more active
- This suggests HL is also a feature within a connected brain
HOWEVER
Bad - lacks mundane realism as it is an artificial task
Bad - Sperry could lack generalisability
- He did not use a control group with epilepsy
- This could mean differences in processing were from epilepsy, not lack of corpus callosum
- This matters because it may mean his findings lack generalisability to people who do not have epilepsy
Good - Research support from more split brain research
- Further research showed that split brain patients are faster to identify the odd one out, supporting the idea that they have different mental processing
- This matters because it supports Sperry’s ideas of Hemispheric Lateralisation
What is Plasticity/neuroplasticity?
The brain’s ability to change and adapt in its function and physical structure in response to its environment
What can the changes be in plasticity?
Fast or Slow
Positive or Negative
What age does the brain’s synaptic connections peak at?
3 years old
How many synaptic connections does a 3 year old have?
Around 15,000
What is Cognitive Pruning?
Deleting rarely used synaptic connections
How can Cognitive Pruning be used in plasticity?
New neural connections can be formed in response to new demands, and old unused ones can be deleted
Who is the key researcher for plasticity?
Maguire et al (she/her)
What was Maguire’s sample?
The brains of 16 male London Taxi Drivers who had been driving for at least 18months
What was Maguire et al’s procedure?
They observed 16 male London Taxi Drivers’ brains using MRI scans
They compared this to a control group of 50 people
What did Maguire et al find?
There was significantly greater volumes of grey matter in the posterior hippocampus in the taxi drivers compared to the control group
There was a positive correlation between the more experience the drivers had and the volume of grey matter
What is the Posterior Hippocampus associated with?
The development of spatial and navigational skills
What is grey matter?
Areas of the brain that are very dense with active neurons
What is white matter?
Areas of the brain that are less dense with active neurons but connect the areas of grey matter
Why did Maguire use London Taxi Drivers for her research?
They had to pass a test called ‘the Knowledge’ that consisted of highly complex questions about routes in London.
Drivers had to learn the names and directions of every street and junction in London, as well as important landmarks and stations.
What conclusions can be made from Maguire’s findings?
The learning for ‘the Knowledge’ altered the cab drivers’ brain structure
Plasticity exists
Evaluate Plasticity
Bad - plasticity may have negative behavioural consequences
- Brains’ adaptation to prolonged drug use has been found to lead to poorer cognitive functioning in later life
- In addition to this, 60-80% of amputees experience ‘Phantom Limb Syndrome’, where they still experience sensations in their missing limbs due to cortical reorganisation in the somatosensory cortex after limb loss
- This suggests not all brain adaptations are beneficial
Good - Plasticity may be a life-long ability
- Although it was previously suggested that plasticity slows down after the age of 21, research has shown that 40 hours of golf training produced changes in the neural representations of movement in 40-60 year old participants
- fMRI scans showed increased motor cortex activity compared to a control group
- This suggests plasticity is life-long
Good - Nurse student support
- med school patients had a brain scan before and after revising for their final exams
- there were increases in grey matter after revising, suggesting plasticity exists and adapted to fit more information