1.2 Biopsychology (The Brain) Flashcards
What is localisation of function?
The theory that different areas of the brain are responsible for specific behaviours, processes or activities
What does localisation suggest in regard to injury?
If a certain area of the brain becomes damaged through illness or injury, the function associated with that area will also be affected
What is the brain divided into?
- Right hemisphere
- Left hemisphere
What are the 6 areas in the brain?
- Motor area
- Somatosensory area
- Visual area
- Auditory area
- Broca’s area
- Wernicke’s area
What 4 centers are the hemispheres subdivided into?
- Frontal lobe
- Parietal lobe
- Occipital lobe
- Temporal lobe
What is the motor area and where is it located and what does damage to the area lead to?
- In the back of the frontal lobe
- Controls voluntary movement in the opposite side of the body
- Damage to this area may result in a loss of control over fine movements
What is the somatosensory area and where is it located and what does damage to the area lead to?
- At the front of both parietal lobes
- Where sensory information e.g heat from the skin is represented
- Damage to this area may result in a loss of tactile perception
What is the visual area and where is it located and what does damage to the area lead to?
- Located in the occipital lobe
- Receives and processes visual information (sends information from right visual field to left visual cortex)
- Damage to this area can produce blindness in the visual field
What is the auditory area and where is it located and what does damage to the area lead to?
- Located in the temporal lobes
- Analyses speech-based information
- Damage to this area may produce partial hearing loss
What is Wernicke’s area and where is it located and what does damage to the area lead to?
- Located in the left temporal lobe
- Responsible for language comprehension
- Damage to area causes Wernicke’s aphasia (speech production of nonsense words)
What is Broca’s area and where is it located and what does damage to the area lead to?
- Located in the left frontal lobe
- Responsible for speech production
- Damage to area causes Broca’s aphasia (characterised by slow, laborious speech)
What does lateralisation suggest?
The two halves of the brain are functionally different, certain mental processes and behaviours mainly controlled by one hemisphere rather than the other
Two strengths and a limitation for localisation of the brain
1. Evidence from neurosurgery:
- different areas of brain linked to mental disorders
- neurosurgery targets areas of the brain e.g cingulotonomy (isolating a region called cingulate gyrus which is involved in OCD)
- Dougherty et al: reported 44 people with OCD who underwent a cingulotonomy
- after 32 weeks 30% had a successful response + 14% had a a partial response
- behaviours associated with specific mental disorders can be localised
2. Evidence from brain scans:
- Peterson et al (1988): demonstrated how Wernickes area active for listening task and Broca’s active for reading task
- LTM studies by Buckner + Peterson (1996): revealed semantic and episodic memories reside in different areas of prefrontal cortex
- confirms localised areas for everyday behaviours, objective methods provided scientific evidence
3. Language localisation questioned:
- language may not just be localised to Broca’s and Wernicke’s areas
- advances in brain imaging techniques e.g fMRIs/neural processes studied with more clarity
- language function distributed holistically and identified across the cortex including right hemisphere
- not confined to key areas which contradicts localisation theory
What in contralateral wiring?
How each side of the brain controls the opposing side of the body
What is split-brain research?
Involves severing the connection between the right and left hemisphere, to analyse how the hemispheres function when they cant communicate with each other
Describe Perry’s split-brain research
- 11 people who had split-brain operation studied with an image projected to RVF and a same/different image projected to LVF
- The information could not be conveyed from one hemisphere to another in a split-brain patient
- When object shown to RVF, the participant could describe what was seen but saw nothing when shown to LVF
- Participants could not give verbal labels to objects projected to LVF, but could select a matching object using their left hand
- Supports the view that LH is verbal and RH is silent but emotional
AO3 for hemispheric lateralisation
1. Lateralisation in the connected brain: even though connected the brains process differently, Fink et al (1996) used PET scans to identify what areas active during visual task, participants with connected brain attended to global elements of an image and RH was more active, when asked to focus on finer detail then LH was dominated, hemispheric lateralisation is feature of the connected brain as well as the split-brain
2. One brain: LH as analyser and RH as synthesiser may be wrong, there may have different functions but there is no dominant side, Nielsen et al (2013) analysed brain scans of 1000 people and found people use different hemispheres for different tasks, but no evidence of a dominant side
AO3 for split-brain research
1. Research support: Luck et al (1989) showed that split-brain participants performed better than connected controls on certain tasks e.g faster at identifying odd one out in array of similar objects, KIngstone et al (1995) in normal brain LH’s cognitive strategies are diminished by the inferior RH, supports Sperry’s findings that left and right brain are distinct
2. Generalisation issues: casual relationships hard to establish, in Sperry’s study split-brain participants compared to neurotypical control group, one issue was none of the participants in the control had epilepsy, confounding variable, any differences observed may have been due to epilepsy rather than split-brain, some of the unique features of the split-brain may have been due to epilepsy
3. Ethics: split-brain operation not performed in purpose of research, no harm to participants, all procedures explained so full informed consent HOWEVER trauma of operation may mean participants did not fully understand implications of their agreement, became subject to repeated testing over time, may have caused stress
What is plasticity?
The brains tendency to change and adapt as a result of experience and new learning
What is functional recovery?
The brains ability to redistribute or transfer functions usually performed by damaged areas to other undamaged areas
What is synaptic prunning and what does it enable?
- When rarely-used connections are deleted and frequently used connections are strengthened
- Enables life-long plasticity where new neural connections are formed in response to new demands in the brain
Describe Maguire el al (2000) research and findings into plasticity
- Studied the brain of London taxi drivers and found more volume of grey matter in hippocampus than matched control group
- Drivers must take a test which assesses recall of streets and routes
- Found that this learning experience alters the structure of taxi drivers brains
- Found the longer the taxi drivers had the job, the more pronounced the structural difference
What is the role of grey matter?
Associated with the development of spatial and navigational skills
Describe what happens to the brain during functional recovery
- The brain is able to rewire and reorganise by forming new synaptic connections close to area of damage
- Secondary neural pathways that not typically used for certain functions are activated
What are the 3 structural changes in the brain during functional recovery?
- Axonal sprouting: the growth of new nerve endings which connect with undamaged nerve cells
- Denervation supersensitivity: axons that do a similar job are aroused to compensate with the lost ones
- Recruitment of homologous (similar) areas: on the opposite side of the brain specific tasks can still be performed
One strength and limitation for plasticity
1. Negative plasticity:
- negative behavioural consequences of plasticity
- Medina et al (2007): evidence shows brains adaption to prolonged drug use leads to poorer cognitive functioning and dementia
- 60-80% amputees experience phantom limb syndrome (unpleasant and painful sensations) due to cortical reorganisation in somatosensory cortex
- brains ability to adapt to damage not always beneficial
2. Age and plasticity:
- may be life-long ability
- Bezzola et al (2012): how 40 hours of golf training led to changes in neural representation in participants aged 40-60
- using fMRI observed increased motor activity in golfers compared to control
- suggests more efficient neural representations after training, plasticity can continue throughout life span
AO3 for functional recovery
1. Real-world application: understanding processes involved in plasticity led to neurorehabilitation, understanding possibility of axonal growth encourages new therapies e.g constraint induced movement therapy used with stroke patients where they repeatedly practice with affected part of their body while unaffected part is restrained, research into recovery is useful as helps medical professionals know when intervention needed
2. Cognitive reserve: level of education may influence recovery rates, Schneider et al (2014) revealed that more time that people with brain injuries spent in education, the greater their chances of a disability free recovery, 40% of those with DFR had more than 16 years education compared to 10% with less than 12 years education, implies people with injury who have insufficient DFR less likely to achieve full recovery
What are the 4 ways of studying the brain?
- fMRI
- EEG
- ERP
- Post-mortem examinations
What are EEGs?
A method that measures electrical activity within the brain via electrodes that are fixed to the scalp using a skull cap
What are fMRIs?
A method that detects the changes in both blood oxygenation and flow as a result of neural activity in specific parts of the brain
What are ERPs?
A method that isolates the electrophysiological response of the brain to specifc sensory, cognitive or motor events from EGG data
What are post-mortem examinations?
A technique involving the analysis of a persons brain following their death and comparing to an neurotypical brain (likely to be those who have a rare disorder or unusual deficits in cognitive processing)
What is haemodynamic response?
When a brain area is more active it consumes more oxygen, and to meet this demand blood flow is directed to the active area
What are activation maps?
Three-dimensional images showing which parts of the brain are involved in particular mental processes
Why are EEGs useful?
May indicate neurological abnormalities such as epilepsy, tumors or sleep disorders
What is strength and limitation of fMRIs?
- Does not rely on radiation: if administered correctly it is risk-free, non-invasive and straightforward to use
- Expensive: compared to other techniques
What is a strength and limitation of EEGs?
- Real world application: useful in studying stages of sleep and diagnosing epilepsy, can be easily detected on the screen
- Generalised nature: EEG signal not useful at pinpointing exact source of neural activity, does not allow researchers to distinguish between activities operating in different locations
What is a strength and limitation of ERPs?
- Real-world value: more specificity in measurements than EEGs, frequently used to measure cognitive functions and deficits
- Methodology: lack of standardisation in methodology between different studies, difficult to confirm findings, background noise and extraneous material must be completely eliminated
What is a strength and limitation of post-mortem examinations?
- Real-world value: vital in providing foundation for early understanding of key brain processes, Wernicke and Broca both relied on these studies, establishing links between brain activity decades before possibility of neuroimaging
- Causation: observed damage may not be linked to deficits under review but rather unrelated trauma or decay
Describe the spatial and temporal resolution for fMRIs
- High spatial resolution: depicts detail by the millimetre, clear picture of how brain activity is localised
- Poor temporal resolution: 5-second time lag behind the image, may not truly represent moment-to-moment brain activity
Describe the temporal resolution for EEGs
- High temporal resolution: accurately detect brain activity at a single millisecond
Describe the temporal resolution of ERPs
- High temporal resolution: so frequently used to measure cognitive functions and deficits
What is the difference between spatial and temporal resolution?
- Temporal: the accuracy of a scanner in relation to time
- Spatial: the smallest feature that the scanner can detect
What is the purpose of split brain research?
Allows researchers to test lateral functions of the brain in isolation
What are the assumptions of the roles of the hemispheres?
- RH = synthesiser
- LH = analyser
