Brain

• Localisation of functin

  The idea that the brain is split into specific areas that control for abilities, or is it all working together

  Historically it was believed that it was holistic but research began to reveal that we have particular areas for particular things
• Phineas Gage

  Phineas, a 25 year old man worked on railway lines in America 1848. There was an accident one day where explosives went off and these catapulted a large iron tod into his head. This rod entered his left cheek and came out the top of his skull.

  Phineas survived this injury. He lost his left eye and a large portion of his frontal lobe

  But Phineas experienced changes in his personality becoming short tempered and angry
• Frontal lobe

  We have seen from Phineas Gage that this is important in emotional regulation, but is also involved in decision making, judgement and concentration
• Motor cortex

  Located in the frontal lobe

  Controls voluntary movement

  The body is mapped out in brain regions where physical sections of the brain represents different parts of the body
• Wernicke's area

  Location - Left hand side of brian only in temporal lobe

  Function - language comprehension

  It was discovered from patients who were able to produce language but not understand it, they will speak fluently but with no meaning
• Parietal lobe

  Processing sensory input, sensory discrimination, body oreintation somatic procesing
• Somatosensory cortex

  Location - Parietal lobe

  Function - processes sensory information from all parts of the body
• Temporal lobe

  Auditory processing in all forms producing speech, interpreting speech and some memory processing
• Auditory cortex

  Location - Temporal lobe

  Function - This area analysis sound based information. It allows you to gage the understanding of words and put together meaningful language
• Broca's area

  Location - Left hand side of the brain only - in frontal lobe

  Function - Language production

  Damage causes Broca's asohasia which is slow and difficult speech
• Occiptial lobe

  Visual processing the incoming visual information from the eye and interpreting this information
• Visual cortex

  Location - Occiptial lobe

  Function - processes the basic elements of the information and then processes the meaning of this in terms of the objects in our environment
• Petersen et al (1988)

  Petersen et al (1988) used brain scans to demonstrate how Wernicke's area was active during a listening task and Bronca's area was active during a reading task. This suggests that each brain area has a specific function relating to language, Wernicke's area for understanding it Bronca's area for producing it
• Tulving et al (1995)

  Tulving revealed that sematic and episodic memories reside in different parts of prefrontal cortex. this again supports that areas of the brain may have very specific functions, one for sematic memory and one for episodic memory

  ❌ the study involved brain scan techniques the number of participants is likely to be small therefore applying these findings to everyone's brains may be inappropriate and we may find that its not the case for everyone

  ✔️brain scan techniques are highly scientific and objective therefore Tulving's findings are reliable and likely to be valid
• what is hemispheric lateralisation?

  The idea that the whole brain is split into two hemispheres which are lateralised this means that the right hand side of the brain controls the left hand side of the body and vice versa
• What does the left hand brain control?

  • Controls the right hand side of the body

  • Heavily involved in speech production and comprehension

  • Believed to have an emphasis on tasks involving logic

  • Analyser
• What does the right hand brain control?

  • Controls the left hand side of the body

  • Has superior drawing abilities

  • Broadly believed to be involved in creative abilities

  • Emotion

  • Synthesiser
• Sperry's procedure

  An image or word is projected in a way that it only enters either the left or the right visual field. Information in the right visual field is processed in the left occipital lobe and in the left visual field its the right occipital lobe. in a normal brain however the information is then shared out so that both hemispheres receive it. in someone with split brain this doesn't happen so one side of their brain holds information that the other doesn't
• Sperry's findings

  The picture shown to the right visual field means left hemisphere processing. This results in the person being able to identify what they have seen easily verbally. Picture shown to left visual field means right hemisphere processing. The person struggles to describe what they have seen. This is because speech production is controlled by broca's area in the left hemisphere
• Sperry's findings

  Recognition by touch - picture shown to left eye means right hemisphere processing. Although they are unable to verbalise what they can see, Sperry found that individuals could match a similar object to that seen by touch. For example, if shown a look, then given a range of objects that they could not see, they would select a key as the matching object, without being able to say what they had seen.
• Sperry's findings

  Draw what you've seen- If the patients are shown a picture to the Left visual field they will not be able to tell you what they have seen. But if they are presented a pen in their left hand they can draw it Draw what you've seen- If the patients are shown a picture to the Left visual field they will not be able to tell you what they have seen. But if they are presented a pen in their left hand they can draw it

  So this supports that the right hemisphere may be more creative
• Sperry's research limitation

  There are issues with Sperry's research such as its lack of generalisability. Split brain patients are very rare; therefore, only 11 people participated in Sperry's methodology. These people suffered extreme epilepsy and were compared to a control group without epilepsy, this introduces a confounding variable, therefore the results will lack meaning in the modern day
• Advantage of Sperry's research

  The research in this area has helped to broaden our understanding of the brain and has helped to foster new research into this area. There have also been philosophical debates stemmed from this research, including the idea that we may have complete duality of the brain
• Research Support of Sperry's research

  Fink et al (1996) have provided support for hemispheric lateralisation in a healthy brain. He gave participants a visual processing task. He found that when participants were asked to attend to the global elements of the picture, for example, looking at a picture of a forest, they used their right hemisphere more, when asked to attend to finer details of the image, for example, a single tree, they used their left hemisphere more.

  This research support increases the validity ∴ the credibility will increase, leading to positive impacts in the real world.
• Opposing arguement of Sperry's research

  The research in this area cannot explain cases of extreme brain damage such as that of Jody who had her entire right hemisphere removed. She was able to recover much function including the control of the left hand side of her body
• Plasticity

  Neutral plasticity refers to the idea that the brain is plastic, it can respond to experience by changing and shaping itself. Gopnik et al (1999) showed that synaptic connections their peak at 2-3 years of age with around 15,000 after this they decline to around half in adulthood
• How does Plasticity occur

  Synaptic pruning - Those connections that are strong and regularly use are kept, those that are weak are 'pruned' away and removed so as to retain space for new or existing neural pathways
• Maguire London cabbie study - plasticity

  In this study, the brains of London taxi drivers were compared to a control group's brains. They found that the size of the Posterior hippocampus was bigger in taxi drivers than control participants. They also found that the longer they had been taxi drivers the larger the difference to the control groups
• What is functional recovery?

  This refers to the brains ability to regain functions which may be lost as a result of damage . When damage firsts occurs then function may be lost. However over time the damage can be repaired and function recovered. This doesn't happen in all cases and there are many variables which affects the brains ability to do this ,it is an area not fully understood yet
• How does functional recovery work?

  • Recruitment of homologous areas on the opposite side of the brain sometimes functional recovery occurs if healthy brain regions take over the function of those that are damaged

  • Neuronal unmasking - can involve your brain activating existing dormant pathways and beginning to use them. It is perhaps possible that the brain developed some reserve systems which became active once they are damaged

  • Axon sprouting - your brain grows new axons and blood vessels which repair the damage that has occurred
• Wall (1977) and neuronal unmasking:

  He was the first to identify neuronal unmasking. He found that the brain may create dormant synapses which only become active once damage has occurred. Their function is blocked but they exist anatomically. These can become active when important connections are damaged and will allow the brain to continue communicating
• What is an fMRI ?

  • fMRI works by detecting the changes in blood oxygenation and flow that occurs as a result of neural (brain) activity in specific parts of the brain

  • An active brain area consumes more oxygen

  •fRMI produces 3D images that are activation maps, showing which parts of the brain are using larger amounts of oxygen and are therefore more active
• Strengths of fRMI

  •fRMIs are virtually risk-free, non-invasive and straightforward to use

  • It produces images that have very high spatial resolution,giving detail by the millimetre
• Weakness of fMRI

  • fRMI is expensive compared to other neuroimaging techniques and can only capture a clear image if the person stays perfectly still

  •fRMI can only measure blood flow in the brain. It cannot home in on the activity of individual neurons and so it can be difficult to tell exactly what kind of brain activity is being represented on the screen
• What is an EEG

  • EEGs measure electrical activity within the brain via of electrodes that are fixed on the scalp usually using a skull cap

  • The scan recording represents the brainwave patterns that are generated from the action of millions of neurons providing an overall account of brain activity

  • EEGs are often used by clinicians as a diagnostic tool

  • This is because unusual arrhythmic patterns of activity may indicate neurological abnormalities such as epilepsy
• Strengths of EEGs

  • EEGs are important in the diagnosis of conditions such as epilepsy

  • Provides a real-time reading of brain activity.it can be left running whilst a participant does a task, rather than it being a simple photograph of the brain
• Weaknesses of EEGs

  • EEGs tend to produce very generalised information so it is not useful for pinpointing the exact source of neural activity

  • EEGs do not allow researchers to distinguish between activity originating in different but adjacent locations of the brain
• What is ERPs

  • ERPs are a way of teasing out and isolating specific neural responses associated with sensory,cognitive and motor events

  • ERPs work by using a statistical averaging techniques, that filters out extraneous brain activity from the original EEG recording leaving only the responses that relate to say the presentation of a specific stimulus

  • Event related potentials remain; types of brainwaves that are triggered by particular events
• Strengths of ERPs

  • ERPs partly address the limitations of EEG

  • ERPs bring much more specificity to the measurement of neural processes than Could be achieved using raw EEG data

  • Researchers have been able to identify many different types of ERP and describe the precise role of these in cognitive functioning including parts of working memory
• Weaknesses of ERPs

  • Critics have pointed to a lack of standardisation in ERP methodology between different research studies making it difficult to confirm findings

  • All background noise and extraneous material must be completely removed which is not easy to do