Biopsychology (A2) Flashcards
What is lateralisation
The dominance of one hemisphere of the brain for a particular physical and psychological function
E.g. Left hemisphere is dominant for language
What is localisation
The theory that specific areas of the brain are associated with particular physical and psychological functions
What is contralateral
When the right hemisphere controls the left side of the body and vice versa
E.g. what you see in the right visual field is processes by your left hemisphere
The left hemisphere is dominant for speech
What are the two areas called in the left hemisphere that help produce and understand speech
- Broca’s area
- Wernicke’s area
What does Broca’s area do
Responsible for converting thought into speech
What does Wernickes area do
Plays an important role in understanding other people’s speech and producing speech which makes sense
What happens if there’s damage to either brocas or Wernickes area
Result in Aphasia
This is inability or impaired ability to understand or produce speech
Detail vs holistic
What hemisphere is used to describe a picture in detail
What hemisphere is used to describe a picture holistically
Detail= Greater activity in the left hemisphere
Holistic= Greater activity in the right hemisphere
What hemisphere deals with recognising emotions and spatial relationships
Right hemisphere
Who are split-brain patients
Individuals who have undergone a corpus callosotomy, meaning a large part of their corpus callosum is cut
Why did they have a large part of their corpus callosum cut and the result of it
Large part of the corpus callosum was cut as it was a way to treat epileptic sufferers.
As a result of this procedure, the 2 hemispheres cannot communicate with each other
Aim of split brain research
To investigate the hemispheric functioning of split brain patients
Method of split-brain research
- Quasi experiment
- 11 participants who’ve had their corpus callosum severed to treat severe epilepsy
- Participants were asked to perform range of tasks, and performance was compared to participants with no inter-hemispheric disconnection
What were the tasks in split-brain research
Part of the method
- Presenting information to one hemisphere by sending it to one visual field (they were blindfolded in one eye)
- Other tasks, their hands were screened from them so they could not see objects placed in front of them, and they had to pick up that object with a certain hand
Results of the split-brain research
1- Participant saw screwdriver in left visual field, therefore shown to right hemisphere. Participant saw ‘nothing’ as left hemisphere controls language not right
2- Participant saw screwdriver in left visual field, therefore shown to right hemisphere. Participant was able to pick it up as right hemisphere controls left arm and was told to pick it up with left arm
3- Participant saw baseball with right visual field, therefore shown to left hemisphere. Participant could describe what he saw as left hemisphere controls language
Conclusion for split brain research
- Left hemisphere is Verbal, right hemisphere is non-Verbal
- Therefore, when information is presented to left visual field, therefore right hemisphere, the participant couldn’t communicate what he saw as the two hemispheres cannot communicate (shows lateralisation in the brain)
- 2nd task, of motor movements, happened because the brain is contralateral. Motor tasks are contralateral
Evaluate split-brain research
S- Standardised procedure, therefore very reliable, if repeated you get same results
L- Results cannot be generalised, as epileptic patients were used
L- Ethical issues, as it can cause psychological harm, discovering their inability to perform certain tasks
L- Small sample of 11 PP’s, findings are not representative of the target population
L- Quasi experiment, cannot randomly allocate participants, therefore lack of control of variables reducing validity
What does split brain research show evidence for
Lateralisation
E.g. helps us know left hemisphere is for speech therefore would know why stroke patients with damage to their left hemisphere have impaired speech
Where specifically is the Broca’s area located in the brain and it’s function
Where specifically is the Wernickes area located in the brain and it’s function
Broca’s area= Left frontal lobe- involved in language production
Wernickes area= Left temporal lobe- involved in language comprehension/understanding
What are the 4 cortex’s/areas
Motor cortex
Somatosensory cortex
Visual cortex
Auditory cortex
Where is the motor cortex and whats it’s function
- Located in the Frontal lobe in BOTH hemispheres (ones side of brain controls muscles on opposite side of body, contralateral)
- Motor cortex is responsible for voluntary
movements by sending signals to the muscles in the body
Damage to this results in impaired movements
Where is the somatosensory cortex and what’s its function
- Located In the Parietal lobe in BOTH hemispheres (one side of brain receives sensory information from opposite side of body, contralateral)
- Somatosensory cortex receives sensory information from the skin, to procedure sensations related to pressure, pain, temperature etc.
Where is the visual cortex and what’s its function
- Located In the Occipital lobe in BOTH hemispheres (information in left visual field is processed in right hemisphere and vice versa)
- Visual cortex receives and processes visual information. Contains different parts that process different parts of information (colour, shape, movement)
Where is the auditory cortex and what’s its function
- Located In the temporal lobe in BOTH hemispheres (information from left ear, processed in right hemisphere, vice versa)
- Auditory area responsible for analysing and processing acoustic information (speech)
What are the 4 lobes and the function of each
Think of the 4 cortex’s
Parietal lobe= Location for sensory and motor movements (somatosensory cortex)
Frontal lobe= Location for awareness of what we’re doing (our consciousness) (Motor cortex)
Temporal lobe= Location for auditory ability and memory acquisition (Auditory cortex)
Occipital lobe= Location for vision (visual cortex)
Peterson (1988) study on supporting evidence for localisation
Method= Used brain scans to investigate when Wernickes area and when Broca’s area were active during reading and listening
Results= - Wernickes area was active during a listening task (understanding speech)
- Broca’s areas was active during a reading task (speech production)
Conclusion= Shows support for brain localisation as specific areas of the brain are used for specific functions
Evidence against localisation
- Brain plasticity
- The fact rehabilitation can work following brain injury suggests functions are not localised
- However, can be argued that as many brain damaged patients never fully recover their function, there is some localisation with certain areas of the brain
Brocas study on a patient called ‘Tan’
- Patient called ‘Tan’ can understand spoken language, but cannot speak or express thoughts writing.
- Post-mortem showed a lesion to his left frontal lobe
METHOD= - 8 other patients had same language deficits with lesions to their left frontal lobe
RESULTS= - Found that patients with damage to these areas in the right hemisphere didn’t have the same language problems
CONCLUSION= Found that the left frontal lobe is critical for speech production
Wernickes study
Method, results, conclusion
Method= Post-mortem on patients
Results= His patients who had lesions in their left temporal lobe could speak but were unable to understand language
Conclusion= Supports the fact brain functions are localised
Define brain plasticity
The brains tendency to change and adapt as a result of experience
What’s functional recovery
3 examples of it
It’s a type of plasticity
It’s the ability of the brain to change and adapt to compensate for lost function
- Increased brain stimulation (recruitment of similar areas on the opposite side of the brain)
- Axon sprouting
- Denervation super sensitivity
What is synaptic pruning
As we age, rarely used connections are deleted and frequently used connections are strengthened
What’s axon sprouting
When existing neurons grow new axons to connect to adjacent neurons.
What’s denervation super sensitivity
To compensate for the loss of axons in a pathway the remaining axons become more sensitive
Kuhn (2014) study on playing video games
Method, results
Method= Video game training group VS control group
- Video game training group= - Increase in grey matter in various parts of the brain
- New synaptic connections in brain areas associated with spatial navigation, working memory and strategic planning
Maguire et al (2000) study on taxi drivers
Results and conclusion
Results:
- Increase grey matter in brains of taxi drivers, compared to non-taxi drivers
- Increased grey matter was found in hippocampus region
- Positive correlation found between length of time spent driving taxi and size of hippocampus
Conclusion:
- These show the brains ability to change (increases grey matter in hippocampus) as a result of experience (driving a taxi)
What are the 4 different ways of studying the brain
- Functional Magnetic Resonance Imaging (FMRI)
- Electroencephalogram (EEG)
- Event Related Potentials (ERP)
- Post-mortem examination
What’s an Event Related potential (ERP)
- Electrodes on the brain, like EEG, but presents a stimulus many times, creating a smooth curve of activation by combining data
Strengths and weaknesses of ERP’s
Strengths: - Allow researchers to isolate and study individual cognitive processes
- Good temporal resolution
Weaknesses: - Poor spatial resolution
- Can’t measure deep in the brain
What’s an electroencephalogram (EEG)
EEG is 23-24 electrodes that are attached to a cap filtered with gel. The read out from each electrode is sum total of activation of the brain cortex under the electrode. Displayed as brain waves
Strengths and weaknesses of an EEG
Strengths: - Good temporal activity
- Cheaper than alternative, like FMRI
- Can be used whilst patient moves
- Historically important in understanding brain activity in things such as sleep research
Weaknesses: -Poor spatial activity
- Can’t Detect deep within the brain
What’s a Functional Magnetic Resonance (FMRI)
Detects blood flow and looks at active areas and low active areas, whilst doing a cognitive activity
Strengths and weaknesses of an FMRI
Strengths: - Good spatial resolution
- FMRI is non-invasive and safe compared to radiation scans such as PET
Weaknesses: - Poor temporal resolution. Many brain processes are too fast to study
What’s a post-mortem examination
Brains precisely cut after treatment (dissected). Unhealthy brains are dissected (brains suffered from trauma or illness) then is compared with a healthy brain
Strengths and weaknesses of a post-mortem
Strengths: - High spatial resolution
- Theories are generated (Broca)
- Significant in historical development of understanding brain functioning such as language centre (Broca and Wernicke)
Weaknesses: Not conducted on a living brain
Factors that affect functional recovery
- Age= Older you are the less you recover
- Sex= Females recover quicker/better function as it’s seen they’re less lateralised
- Education= Better the education, the better the recovery
Danelli et al study (2013) on Age affecting functional recovery
Method, results, conclusion
Method= Italian boy at age 2 years had left hemisphere taken out due to benign tumour, therefore speech disappeared too.
Results= Underwent rehabilitation and his language abilities started to improve at 5 years old. Continued to improve over next 3 years to the point no problems of language ability were reported.
Conclusion= Increased brain stimulation occurred where the right hemisphere compensated for the loss of the left hemisphere
Ratcliffe et al (2007) study on how Gender affects functional recovery
Method, results, conclusion
Method= Assess level of recovery in cognitive skills in 325 patients receiving rehabilitation aged 16-45 years at time of brain injury
Results= Female patients performed better on tests of attention/working memory and language and makes performed better on visual analytic skills.
Conclusion= Results suggest better recovery for women, illustrating effect of gender on functional recovery following trauma
Evaluation of localisation and lateralisation
- Research demonstrates loss of certain functions if damage is caused to particular area of brain. E.g. Broca and Wernickes case studies (aphasia). Suggesting it’s localised
- FMRI’s support research on language centres, showing activation in regions when performing reading out loud(Broca’s area) and listening tasks(Wernickes area)
- Systems like language are more distributed functions. Suggests not one area is independent. However, motor and somatosensory functions are highly localised
Evaluation of plasticity and functional recovery (AO3)
- Maguires study
- Danelli’s study (case study)
- Research on brain plasticity and functional recovery has been useful in rehabilitation. E.g. Constraint induced Therapy, makes them improve via functional reorganisation
- Research on individuals recovering lost function help psychologists understand more about functions of regions of the brain that were damaged
