brain and neuropsychology

based on the edexcel specification

what is the function of the temporal lobe

processing sound based information

what is the function of the occipital lobe

processing viual information and making sense of it

what is the function of the frontal lobe

decision making and impulse control

what is the function of the parietal lobe

perception and facial recognition

what is the function of the cerebellum

motor control and coordination

function of the right hemisphere

Control of left hand Left visual eld Spatial awareness Creativity Recognising faces Musical ability

function of the left hemisphere

Control of right hand Right visual eld Left hemisphere Right hemisphere Speech Understanding written language Understanding what is heard Logical thinking

what is laterlisation of function

the different jobs that are done by each half of the brain; each hemisphere will have different specialist roles that it performs.

what does the corpus callousome do

a thick bundle of nerve fibres connecting the two hemispheres of the brain so they can communicate with each other

what are the strengths of the sex differences between males and females

harasty et al -the brain that process and produce language are slightly bigger in females compared to males.

rilea et al - found that males were better at some spatial tasks, especially those that use a lot of activity in the right hemisphere.

what are the weaknesses of the sex differences between males and females

sommer et al males did not always do better than females on the spatial tasks.

what are neurons

a nerve cell that transmits information

what are synapses

a gap between two neurons that allows messages, in the form of neurotransmitters, to pass from one cell to another

how do synapses and neurons interact

Messages are passed throughout the nervous system, from one neuron to the next, by a process called synaptic transmission . Synapses are tiny gaps between neurons that allow chemical messages to pass between them. An electrical impulse is triggered inside the cell body of a neuron

what is the function of a neurotransmitter

chemicals released by neurons that pass messages from one neuron to one synapse

what does the cns do (centralnervous system )

involves the brain and spinal chord interacting with each other via electrical impulses

what is the impact of visual agnosia and what is it

Visual agnosia: an inability to recognise things that can be seen.

they can see perfectly well but cannot understand what they are seeing

what is t mimpact of prosopagnosia

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Prosopagnosia: ‘face-blindness’ or an inability to recognise faces.

people with prosopagnosia cannot recognise family members, including their own children.

Prosopagnosia caused by damage to the back temporal lobe, next to the occipital lobe, known as the fusiform face area (FFA).

symptoms of prosopagnosia

. Some people find that they see all faces as ‘the same’ . Some find that they cannot recognise faces of people that they know really well, while other people have more trouble with matching up pictures of faces that they do not know.

symptoms of agnosia

not being abe to recognise objects

the impact of damage to the prefrontal cortex

keeps our emotions balanced and hlps impulse control .if its damaged dramatic personality changes can occur. Adrian Raine et al. (1997) Murderers had less activity in the pre-frontal part of the brain, making them more impulsive and maybe more aggressive

aims of  Damasio et al (1994

to build a model of Gage’s skull using his actual skull as a guide

procedures of  Damasio et al (1994)

11 parcicpants who had had their corpus callosum cut. They were each given various tasks to test how they processed diff erent types of information in the ‘split-brain’.This means that the left side of each eye would pick up one image (the one on the right of centre), while the right side of each eye would pick up the other image (the one on the left of centre.) The information on the right of the visual fi eld would be passed to the left hemisphere, while information on the left of the visual fi eld would be passed to the right hemisphereOther variations of this task included putting unseen objects into one of the hands and asking them to identify them from touch alone, and placing diff erent objects in each hand and then asking them to feel for them in a large pile of diff erent objects.

findings of  Damasio et al (1994) :results and conclusions

results:When words were shown to the right visual field, the patients had no problem repeating the word back to the researcher. However, when words were shown to the left visual field (sent to the right hemisphere), patients had trouble saying what they had seen. • If a word or picture was shown to the left visual field (right hemisphere), the participants had little trouble selecting an object that matched what they had seen. When the word or picture was shown to the right visual field (left hemisphere), the participants struggled to point to the correct object.

When objects were felt by the right hand (so passed to the left hemisphere), they could name the object. When objects were felt by the left hand, they found it more difficult to say what they could feel. • When two different objects were given to the participant – one in each hand – and after they were asked to feel around in a pile of objects for the two objects, they could only identify each item with the hand that originally held it. If the opposite hand picked up the item, they could not identify it as the item they had held before.

conclusions:Sperry suggested that each hemisphere is capable of working perfectly well without being connected to the other side. However, each hemisphere seems to have its own memories, which, without a corpus callosum, could not be shared with the other side. This caused problems for some activities, supporting the idea that the right and left hemispheres have different roles. The left hemisphere seemed to be better at naming items using words when they had been held by the right hand. responsible for spatial tasks

strengths of  Damasio et al (1994)

Sperry gathered a lot of detailed information, improving the reliability of his study. Another strength is that he designed procedures (such as the splitscreen for presenting visual information) that could be kept the same for each participant. This means that the data was gathered in a reliable way and each participant’s results can be compared more easily

weaknesses of  Damasio et al (1994)

A weakness of Sperry’s study is that the sample of 11 participants is too small to be able to generalise the results very confidently. Very few people have surgery to sever the corpus callosum so the results might not be that useful for explaining how ‘normal’ brains work. Another weakness is that the tasks Sperry had the participants do in the laboratory may be very artificial. It is not often you will be asked to look at a picture with one eye, and then point to the same picture with your hands. This means the results may lack ecological validity.

aims of sperry

to build a model of Gage’s skull using his actual skull as a guide, so that they could map out how the iron rod passed through his head

procedure of sperry

Damasio et al. began by taking pictures and measurements of the skull of Phineas Gage. From the information gathered, they built a virtual 3D replica model of a skull that matched the measurements of Gage’s skull. As the iron rod had been buried with Gage, they were able to take actual measurements of the rod, which was 3 cm in diameter and 109 cm long. They compared this to the parts of the skull that were damaged in order to work out the likely path that the iron bar would have taken as it blew through his head. To do this accurately, they matched up the possible entry and exit points for the iron rod on their model. In total, 20 diff erent entry points and 16 diff erent exit points were tested to try to fi nd the most likely path taken by the rod. Once they had found the fi ve most likely paths, Damasio et al. used the virtual replica model of Gage’s brain to map out which areas would have been damaged in each case.

results of sperry

Damasio et al. found that there was likely to have been damage in both the right and left hemispheres of the frontal lobe in Gage’s brain. They were able to confi dently assume that the brain damage suff ered in the accident was likely to only have aff ected the frontal lobe, and no other areas of the brain. The iron bar would have passed through the left eye socket and upwards through the head (Figure 4.5). This meant that there was likely to have been more damage to the underlying white matter in the left hemisphere than in the right frontal lobe. The white matter is where all of the neurons pass their messages along the axon fi bres. Damaging this area would have meant Gage was unable to pass neural messages in this part of his brain, making it useless. The damage in both hemispheres seemed to be worse in the middle of the underside (ventromedial region), while the top edges (dorsolateral regions) of the frontal lobes were less likely to have been aff ected.

strengths of sperry

One strength of Damasio et al.’s (1994) study is that the researchers were able to use modern-day technology to investigate the data from 1848, meaning the results can be given more scientific status. The use of a computer model meant the evidence could actually be seen, rather than just inferred from the information gathered after the accident first happened. This further increases the scientific understanding of the case of Phineas Gage. Another strength of this study is that we can now make predictions about what changes to behaviour we might expect if someone has damaged their frontal lobes. If a patient damaged the frontal lobe in a similar area to Gage, we can predict that they might be more impulsive and less able to control their behaviour. Knowing this could help the family understand what might happen and why it is happening, and it could also be useful for

weaknesses of sperry

One weakness of Damasio et al.’s study is that, even though they used an exact replica of Gage’s skull, the information about how the accident happened is based on reports originally gathered over 150 years ago. This means that the information might not be very accurate, or is simply a guess from the reports they could find, so it may not be very reliable. There is also a problem in generalising the information about this case study to other people because the brain damage was unique to Gage. It is very unlikely someone else will have exactly the same damage, so the information might not be very useful for helping us to understand what might happen to another person with frontal lobe damage.