localisation and function of the brain

• holistic theory: all parts of the brain are involved in the process of thoughts and actions - Phineas Gage

  Broca and Wernicke: different parts of the brain perform different tasks and are in involved with different parts of the body - brain is split into two, lateralisation - left side of brain controls right side of body etc - contralateral
• areas of the brain:

  1. frontal lobe - motor cortex that controls our movements
  2. temporal lobe - auditory cortex that controls our hearing and ability to comprehend language
  3. occipital lobe - visual cortex that controls our sights
  4. parietal lobe - somatosensory cortex that controls our sense perceptions - touch, heat, pressure

  langauge centres: both left hemisphere

  1. Broca's area: found in frontal lobe - responsible for speech production - PATIENT TAN
  2. Wernicke's area: found in temporal lobe - responsible for language comprehension

  
• evaluation:

  strength:

  • brain scans support, Petersen (1988) used brain scans to demonstrate how Wernicke's area was active during a listening task and Broca's active during a reading task - scientific
  • linked to mental disorders, can help provide treatment specifically if you know the cause and damaged areas

  weakness:

  • Lashley (1950), removed areas of the cortex in rats that were learning a route, no area was proven more significant - takes holistic approach
• hemispheric lateralisation:

  • left side of the brain: responsible for language (Broca and Wernicke)
  • right side of the brain: responsible for visual and spatial, helps to only provide emotional context to language

  contralateral: the left side of the brain controls the right side of the body, right side of the brain controls the left side of the body.

  • Left visual field controls right side of the brain, right visual field controls left side of the brain
• split brain research:

  Sperry(1968): studied on 11 split brain patients who had their corpus callosum cut as they had severe epilepsy.

  1. describing, had them describe two images with one being a whole image and another a specific detail within the initial image -right hemisphere (LVF) the split brain patients cant describe the image -left hemisphere (RVF) allowed them to describe the image as its responsible for language
  2. tactile, blindly react to objects behind a screen and asked to feel similar objects - left hemisphere couldn't describe - right hemisphere could describe
• evaluation of lateralisation;

  strength:

  • Fink (1996) conducted a PET scan during processing tasks, focus on bigger picture, the right hemisphere was active, focus on smaller picture the left hemisphere was active - both sides active

  weakness:

  • Neilsen (2013) analysed brain scans of 1000 participants ages between 7-29. there was evidence of lateralisation but no evidence of dominant hemispheres - proves brain is lateralised but works together as a whole, holistic
• evaluation of sperry:

  strength:

  • ethically and morally acceptable, their operation was not performed for the research
  • application for real-world, better understanding of split brain can help develop treatments

  weakness:

  • small sample of 11, not generalisable
  • cannot be generalised as patients had epilepsy, the behaviour may be a result of this - lacks mundane realism due to artificial tasks
• plasticity: the brains ability to change and adapt its structure based on experiences and new learning

  • 2-3 years old we have 15,000 connections, during infancy the brain experiences growth in the number of synaptic connections
• Plasticity in adult brains: Maguire (2000), studied london taxi drivers and found that they had a significantly greater amount of more volume of grey matter in their hippocampus - responsible for navigational skills

  • more time they were a taxi driver, the more obvious the structural difference

  Draganski (2006), supports Maguire, conducted an experiment on medical students and scanned brains of medical students three months prior and after their medical exams - changes were seen in the hippocampus and parietal cortex
• functional recovery: brains ability to adapt from damage and trauma, transferring these functions to undamaged areas - allows the brain to manage with brain damage, allowing it to recover and deal with the effects
• synaptic pruning: deleting connections that are unused or considered irrelevant and strengthening connections that are used
• Hubel and Wiesel (1963), prevented the visual stimulation of one kittens eye by sewing it up, then found that the visual cortex had started to process the information from the open eye because the other one was shut - when unstitching the eye they found that the kitten had gone blind as the damaged areas transferred functions to undamaged areas
• functional recovery: may not leads to a full recovery, far easier to occur in a child's brain due to higher levels of plasticity produced
• • neuronal unmasking: dormant neurons that have been stored take on function that other neurons have been damaged by
  • neural reorganisation: undamaged areas take over damaged areas
  • neural regeneration: repairing damaged neurons by growing new connections with undamaged neurons
• evaluation of plasticity:

  strength: supporting studies Maguire, Draganski, reinforced idea that the brain canc change and adapt in adult's brain as well as children's

  weakness:
• evaluation of functional recovery:

  strength: supporting study from Hubel and Wiesel, brain experiences functional recovery by changing occipital lobe

  • can also contribute to help treat people with brain abnormalities, repetition of exercises will help strengthen connections and regain functions

  weakness: hubel and wiesel, unethical study and the brain is vastly different from animals to humans, meaning it cannot be applied to support research