Biopsych L6-9 Flashcards
What is Localisation of function?
Refers to the principle that functions (language, memory, hearing etc.) have specific locations within the brain.
Where is the visual cortex located?
The visual cortex is in the occipital lobe of both hemispheres of the brain.
How does the visual centre work?(visual processing)
- Visual processing starts in the retina where light entrees and strikes the photoreceptors.
=> Nerve impulses from the retina are transmitted to the brain via the optic nerve.
=> The majority terminate in the thalamus, which acts as a relay station, passing the information onto the visual cortex
Where is the auditory cortex located?
The auditory cortex lies within the temporal lobe in Both hemispheres of the brain.
How does the auditory centre work? (Auditory pathway)
- The auditory pathway begins in the cochlea in the inner ear
=> sound waves are converted to nerve impulses, which travel via the auditory nerve to the auditory cortex.
=> Basic decoding occurs in the brain stem
=> The thalamus carries out further processing before impulses reach the auditory cortex.
Where is the motor cortex located?
It is located in the frontal lobe of Both brain hemispheres.
What is the motor cortex responsible for?
- It is responsible for the generation of voluntary motor movements.
- Different parts of the motor cortex control different parts of the body.
- These regions are arranged logically next to each other (e.g the religion that controls the foot is next to the region that controls the leg)
- Damage to these areas can cause a loss of muscle function/paralysis in one or both sides of the body.
Where is the somatosensory cortex located?
It is located in the parietal lobe of both hemispheres.
What is the role of the somatosensory cortex?
- This area detects sensory events arising from different regions of the body.
- Using sensory information from the skin, the somatosensory cortex produces sensations of touch, pressure, pain and temperature, which it then localises to specific parts of the body
What is the Broca’s area?
- Paul Broca treated patients who had difficulty producing speech and found that they had lesions to the left hemisphere of the frontal lobe.
- Expressive Aphasia is language/ speech problems (caused by damage to Broca’s areas)
- It affects language production but not understanding
- Speech lacks fluency and patients have difficulty with certain words which help sentences function (e.g ‘it’ and ‘the’
What is Wernicke’s area?
- located in the left hemisphere of the temporal lobe.
- Carl wernicke found that patients with a lesion to this area could speak but were unable to understand language. Concluded that this area is responsible for processing spoken language
- connected to the Broca’s area by a neural loop
- receptive Aphasia is an impaired ability to understand language
Evaluation for localisation (negatives -)
- some functions are more localised than others ( motor and somatosensory functions are highly localised in the cortex where as other functions like personality are more widely distributed)
- individual differences in brain localisation (Bavelier found that when a person engaged in silent reading there are individual differences. They observed activity in the right temporal lobe, left frontal lobe and occipital lobe.)
- issues with case study tan as recent MRI Found many lesions everywhere
Evaluation for localisation(positives +)
- Phineas Gage suffered a traumatic brain injury from a pole which forced his temporal lobe out of his brain. Gage suffered a change of personality after this accident suggesting that our personality at be localised to the temporal lobe.
- brain scan evidence of localisation (Peterson et al used brain scans to show how Wernicke’s area was active during a listening task and how Broca’s area was active during a reading task. Suggesting that language is localised in these areas. As brain scans were used it makes it scientifically valid
- tan broca post mortem case study, found lesions
What is lateralisation if function?
The idea that two hemispheres of the brain have different specialisations.
* the right hemisphere is responsible for the left hand side of the body
* And the left hemp is here is responsible for the right hand side of the body.
Studies have shown that the left hemisphere is dominant for language and the left hemisphere is dominant for recognising faces. These two hemispheres are connected by a bundle of nerve fibres called corpus callosum
Evaluation for lateralisation(positives +)
- brain lateralisation increases neural processing capacity, which is adaptive. By using one hemisphere to engage in a particular task it leaves the other hemisphere free to engage in another function. Rogers et al found that lateralisation in chickens is associated with an ability to perform two tasks simultaneously (finding food and being vigilant for predators.)
Evaluation for lateralisation (negatives -)
- individual differences. JW developed the capacity to speak using his right hemisphere, with the result that they could speak about information presented to the left or right hemisphere
- Does not explain plasticity since studies have only shown one hemisphere being damaged it does not mean that the individual will have an abnormal brain. It has been shown that the other hemisphere can take over and do the work for both suggesting brain plasticity can I’ve come potential limitations with lateralisation
What is split brain research used for?
Split brain research is used to study brain lateralisation as it shows what functions are dominant for which hemisphere.
Describe what Sperry and Gazzaniga did to study split brain
Stare at dot and image presented in l/r visual field
Each visual field goes to opposite hemispheres
What were the split brain patients asked to do in S&G study?
Respond with
- left hand (r hemisphere)
- right hand / verbally (left hemisphere)
