Biopsychology Flashcards
What is the difference between the localisation of function theory and the holistic theory (of the brain)?
Localisation of function: idea that different areas of brain are responsible for different behaviours, processes or activities
Holistic theory: ALL parts of brain were involved in processing of thought and action.
Define brain lateralisation and outline the general rule about lateralisation in the 2 hemispheres?
The idea that the 2 hemispheres are functionally different and that each have functional specialisations
- activity on left-side of body are controlled by right hemisphere and vice versa
What is the cerebral cortex?
The outer layer of both hemispheres, which is about 3mm thick and is what separates is from animals as the human cortex is much more developed
Name the four lobes found on the cortex.
F-POT (drawn clockwise)
- Frontal lobe
- Parietal lobe
- Occipital lobe
- Temporal lobe
Which area is found on the back of the frontal lobe?
MOTOR AREA : Controls voluntary movement in opposite side of body
- damage here may lead to loss of control over fine movements
Which area is found on the front of parietal lobes?
SOMATOSENSORY AREA: processes sensory info such as touch or heat.
Which area is found in the occipital lobe (at the back of the brain) ?
(GIVE EXAMPLE)
VISUAL AREA: Receives and processes visual info from opposite visual fields, e.g left visual cortex processes info from right visual field and vice versa
Which area is found on the temporal lobes?
AUDITORY AREA: analyses speech-based info
Define broad aphasia?
A condition that is caused by damage to the brocas area (area responsible for speech production).
- sufferers speech tends to be slow and lacking in fluency
Define wernickes aphasia
A condition caused by damage to the Wenicke’s area (area in left hemisphere responsible for language comprehension)
- sufferers tend to have fluent speech but speech often lacks in meaning/is nonsense
Evaluate the ‘localisation of function’ theory.
Strengths
- Brain scan evidence: tulving et al found that semantic and episodic memory is found in diffefent parts of the pre-frontal cortex.
- Neurosurgical evidence: dougherty et al found that OCD patients got better after having a cingulatomy (lesioning of **cingulate cyrus)
Weaknesses
4. Lashley research: Lashley found that rats used every part of their cortex to learn a maze. This suggests that learning is distributed in a more holistic way in brain
- Plasticity: research found that when a function is lost, brain reorganises itself to recover lost function. (e.g there are cases about stroke victims being able to recover lost abilities.
Define plasticity
Plasticity = the brains tendency to change and adapt (functionally and physically) as a result of experience and new learning
Describe the findings of one research into plasticity
Maguire et al: found that London taxi drivers showed significantly more volume of grey matter in posterior hippocampus (associated with spatial and navigational skills) than control group.
- the longer the driver had been in the job, the more pronounced was the structural difference
(both are results of learning and experience)
Define functional recovery
Following damage through trauma, the brains ability to redistribute or transfer functions usually performed by a damaged area to other, undamaged areas
What happens in the brain during recovery?
(HINTS:
- new synaptic connections
- secondary neural networks
- axonal sprouting
- reformation of blood vessels
- recruitment of homologous areas
- Brain wires and reorganise itself by forming new synaptic connections close to damaged area.g
- Secondary neural pathways: these would be activated to allow functioning to continue. This process is supported by:
- Axonal sprouting: growth of new nerve endings which connect with other undamaged nerve cells to form new neuronal pathways
- Reformation of blood vessels: to allow flow of oxygenated blood and nutrients to cells
- Recruitment of homologous (similar) areas on opposite side of brain to perform specific tasks: e.g. If brocas area was damaged on left side of brain, right equivalent would take over role. After a period of time, functionality may shift back to left.
Evaluate the theory of brain plasticity
Strengths
- Maguire et al research
- Practical application (contributed to neurorehabilitation) : understanding that plasticity/spontaneous recovery slows down after some weeks has prompted us to use own techniques to maintain improvements in functioning e.g. Movement therapy.
- Gabby Giffords/phineas gage
- Hubel and Weisser: sewed one eye of a cat but still found that visual cortex activity associated with that eye continued to process info from open eye.
- Plasticity maintained with age: research found reduced motor cortex activity in 40-60 yr old golfers when compared with control group. This suggests neural plasticity can continue throughout lifespan)
Limitations
- ** Negative plasticity: theory doesn’t include maladaptive behavioural consequences of brains ability to rewire itself (e.g. Prolonged drug use can result in poorer cognitive functioning as well as dementia)
- Age and plasticity: functional plasticity can reduce with age as brain has greater propensity for reorganisation in childhood as it is constantly adapting to new experiences and learning).
- HUBER AND WEISSER - HIGHLY UNETHICAL
- Phineas Gage results may be due to researchers own subjective experience
Name 4 ways of investigating the brain
- Functional motor resonance imaging (fMRI)
- Electroencephalogram (EEG)
- Event-related potentials (ERPs)
- Post-mortem examinations
How do fMRIs work?
Parts of the brain that are more active require more 02, so blood flow is directed to these areas (Haemodynamic response).
- MRI technology allows researchers to detect changes in blood flow/ detect the areas that are high in O2, and thus, detect the areas that are active.
Evaluate the use of fMRIs.
Strengths
- Safer as it doesn’t use radiation
- Produced images in very high spatial resolution (great detail)
Weaknesses
- Expensive
- Only produces clear image if person stays very still
- Poor temporal resolution (there is a 5 second lag between the image on screen and the initial firing of neuronal activity.
How do EEGs work?
They record tiny electrical impulses produced by the brains activity.
- By measuring characteristic wave patterns, the EEG can help diagnose certain conditions of the brain
Evaluate the use of EEGs.
Strengths
- Has helped with diagnosis of epilepsy
- Contributed to our understanding of stages involved in sleep (ultradian rhythms)
- High temporal resolution (can detect at a millisecond)
Weaknesses
- Cannot pinpoint exact source of neural activity
- Doesn’t allow researchers to distinguish between activities originating in different but adjacent areas.
How do ERPs work?
They show the brain’s electrophysiological response to a specific sensory, cognitive, or motor events, which can be isolated through statistical analysis of EEG data.
- They help researchers view performance of a specific task or the presentation of a specific stimulus.
Evaluate the use of ERPs.
Strengths
- High temporal resolution
- supports localisation as its more specific in terms of measuring neural processes ( it can isolate motor, cognitive or sensory events/responses). e.g. has allowed us to find out the brain’s P300 component is involved in allocating attentional resources and maintaining working memory.
Weaknesses
3, lack of standardisation: In order to obtain pure data, background noise and extraneous material must be eliminated but this is not always possible.
