the frontal lobe - Autism and Asperger Syndrome

Further reading on The theory of Mind – Autism and Asperger Syndrome

Theory of mind is the ability to understand mental state such as beliefs, feeling, desire, hope and intentions. This ability develops rapidly in young children but has slow rates in autism. The sally –Anne test is commonly used to test theory of mind. Neuroimaging studies has located specific region that are activated during theory of mind tasks such as the anterior paracingulate cortex, the superior temporal sulci and the temporal poles bilaterally. However those that have Asperger syndrome show significantly lower activation in this brain region which has been identified as importation for engaging in mentalising task in normal people.      

People with autism suffer from the lack of central coherence which is the cognitive ability to combine together a group of separate features in to a single coherence, object or concept. There is evidence that suggest that test for factual knowledge and focuses attention to detail can lead to high performances whereas test tapping in common sense comprehensions can show low performances. This therefore shows differences in information processing style rather than a deficit. For example when retelling a story normal individual finds it easier to recall gist of the story rather than the specific detail. Whereas those with autism do the opposite therefore suggesting that they have a weak coherence  

The Gestalt psychology argues that it is not the inability to combine information together but rather that they have an enhanced discrimination of individual element. Suggesting that the early stage of sensory processing are intact in autism, but the top-down modulation of these early processing stages which extract global feature of stimulus is not functioning properly.

In addition many have suggested that it is an innate ability however there has been controversial argument that it is a learnt behaviour and perhaps autistic children find it difficult to learn.  

Example of the sally- Anne test

A sally- Ann test is used to judge whether a person has a theory of mind. A child is presented with two doll, sally and Ann each doll has their own box. Sally put a marble in her own box and pop out the room  them Ann pay a tick on sally and takes the marble and hid it under her box, sally come back in the room, the researcher askes the child were would sally look for her marble .     

A child that has a theory of mind, know that Anne played a tick  on her and would look in her own (Sally) box however a child that lack the theory of mind would see the situation through her own point of view and would say that Sally should look under Anne box, children between 6-7 are able to perform well on this task even some children as little as 3.

There is also evidence to suggest that some intelligent autistic can do the test through logical deduction without having the ability of theory of mind whereas those with low intelligence would perform poor on this test.

 Frontal lobes

Describe the main components of the frontal lobes

The Cerebrum: The cerebrum or cortex is the largest part of the human brain, associated with higher brain function such as thought and action. The cerebral cortex is divided into four sections, called "lobes": the frontal lobe, parietal lobe, occipital lobe, and temporal lobe. Here is a visual representation of the cortex:

• Frontal Lobe- associated with reasoning, planning, parts of speech, movement, emotions, and problem solving
• Parietal Lobe- associated with movement, orientation, recognition, perception of stimuli
• Occipital Lobe- associated with visual processing
• Temporal Lobe- associated with perception and recognition of auditory stimuli, memory, and speech

The cerebrum into two halves, known as the left and right hemispheres. The two hemispheres look mostly symmetrical yet it has been shown that each side functions slightly different than the other. Sometimes the right hemisphere is associated with creativity and the left hemispheres is associated with logic abilities. The corpus callosum is a bundle of axons which connects these two hemispheres.

Evaluate the function of the frontal lobes

Compare some of the testing for frontal lobes dysfunction

The problem of measuring frontal lobe abilities is that the test of frontal lobe function does not always measure the ability of the patient

Common methods of measuring frontal lobe ability

1.      Sequent events logically and temporally

2.      To reason abstractly – Wisconsin card sorting test – giving a stack of card  containing  broken down in 4 section red triangle -2 green star  3 yellow cross 4 blue circles  they are giving 2 set of card 64x=128 and are told to organised them in to either colour shape or number and must change after ten correct response to another organising order – results how that patient with frontal lobe damage perform  poorly more error and fail to complete the sorting – other problems is sorting card of 6 into two pile of 3 based on the designs of the card and building block according to high colour and shape – tower of London task  see page 168

3.      To be have spontaneously

4.      Verbal fluency – measured by the controlled oral word association from the multilingual aphasia examination – this test require for the patient to name as many name possible begging with the letter giving – results show that patient perform poorly compared to  controlled group

Give example of symptoms of frontal lobes dysfunctions  

Answer these questions

Do the frontal lobes mediate intelligence?

 How do the frontal lobes effect decision making and reasoning task?

 Are the frontal lobes necessary for the theory of mind?  

Hemispheric Lateralisation

Further Reading on handedness.

Why is there a dominance of right hander this pattern and been observed for over 5000 years. Animal tend to show an equal distribution between left and right pawed, whereas humans show a preference for the right hand. The two cerebral hemisphere process information differently, brain research has put forward the idea that left-handedness is the produced by abnormities in the bran such as a defect caused by a reduction of blood supply to the left hemisphere during the fatal growth. Damage to the left hemisphere can case a shift of dominant limb function to the right hemisphere. However these finding ate not see with premature birth, prolonged labour and breech birth. Another conception is that testosterone can slow down development in the left hemisphere in male foetus suggesting that high levels of testosterone is responsible for left handedness unsurprising this result was  unsubstantial.      

 There has been a debate that left – handedness many have genetic components. This argument claim that it is inherited, whereas left handed parent are more likely to have left handed children evidence to support this claim was adoption studies indicated that adopted children handedness  resembled their birth parent rather than their adopted parent. Additionally researcher  have stated that there is a single gene that in found in right hander and individual that do not have this gene exhibit random handedness however other have rejected this hypothesis because if both parent are left handed and left handedness was a recessive trait then all their children should be left handed. This show that there may be more than one gene involved or other factors may play a role.     

Handedness has many definitions, but is commonly known as the hand that a person uses to write. With this this context there has been debate about this vague definition. Other identifies it as the hand that performs the fastest and precisely, alternatively it can be seen as the hand that is preferred regardless of performances. There has been dispute about the different type of handedness, left or right. Whereas other feel that ambidexterity should also be included in the category. Furthermore there has been critique suggestion that there is two different type of ambidexterity. Paul Broca claim that the person handedness was the opposite side of the of the specialised area, this propose that a right handed person most likely have left hemisphere language dominance specialisation  however there has also been evidence to suggest that left hander also show dominance for language in the left hemisphere. While half of left handers use their right hemisphere, some left hander control writing completely and independently by the right hemisphere in the bran.

Summary of the Topic

The two cerebral hemisphere are not exactly alike. Each hemisphere have specialised functions, in addition some of the neural mechanisms are located primarily in one half of the brain. Paul Broca was the first to suggest that cognitive function is localised in the brain, for instance speech and language abilities showed dominance in the left hemisphere. Wernicke found other area in the left hemisphere that was responsible for language comprehension. Clinical reports have shown not hat around 70-95  of human have a left hemisphere language specialisation therefore around 5- 30 of humans have an abnormal pattern of specialisation  such as showing dominance of language in the right hemisphere or little literalised specialisation.