Cognitive Neuroscience methods

October 29, 2016

One of the most complete

Behavioural and Neuroscientific Methods were invented by Shay M. Anderson and are used to get a better understanding of how our brain influences the way we think, feel, and act. There are many different methods which help us to analyze the brain and as well to give us an overview of the relationship between brain and behaviour.Well-known techniques are the EEG (Electroencephalography) which records the brain’s electrical activity and the fMRI (functional magnetic resonance imaging) method which tells us more about brain functions. Other methods, such as the lesion method, are not as well-known but still very influential in today's neuroscientific research.

Methods can be summed up in the following categories: There are techniques for assessing brain anatomy and others for assessing physiological functions. Furthermore there are techniques for modulating brain activity, analyzing behaviour or for modeling brain-behaviour. In the lesion method, patients with brain damage are examined to determine which brain structures were damaged and to that extent this influences the patient's behaviour.

Lesion method[edit]

The concept of the lesion method is based on the idea to find a correlation between a specific brain area and an occurring behaviour. From experiences and research observations it can be concluded that the loss of a brain part causes behavioural changes or interfere in performing a specific task. This can be noted in such a way that a patient with a lesion in the parietal-temporal-occipital association area has an agraphia, that means that he is not able to write although he has no deficits in motor skills. Consequently generally speaking researchers deduce that if structure X is damaged and changes in behaviour Y occur X has a relation to Y.

In humans lesion are often caused by tumours or strokes. With the upcoming methods it is possible to determine which area was damaged for example by a stroke and therefore deduce a relation between the loss of the ability to speak and this specific damaged brain area. Lesions caused purposely in the laboratory with animals offer a lot of advantages.

First the animals did all grow up in the same environment and have the same age when the surgery is performed. Second on each animal a before-after comparison of performing a task can be observed. And third the control groups can be watched who either did not undergo surgery or who did have surgery in another brain area. These benefits also increase the accuracy of the hypothesis being tested which is more difficult in human research because the before-after comparison and control experiments drop out.

Visualization of iron rod passing through brain of Phineas Gage

In order to upgrade the probability of the hypothetical relationship between a brain area and a task performance a method called double dissociation is carried out. The goal of this method is to prove if two dissociations are independent. More precisely if two patients have each a brain lesion and they show a contradictory disease pattern the ambition of the scientists will be to prove that the two tasks are realized in two different brain areas. Lesions in the Broca-, respectively Wernicke area can serve as an example. The Broca area in the brain is responsible for language processing, comprehension and speech production. Patients with a lesion in this area have a brain damage called Broca's aphasia or non-fluent aphasia. They are not able to speak fluently any more, a sentence produced by them could be: I ... er ... wanted ... ah ... well ... I ... wanted to ... er ... go surfing ... and ... well... Contradictory Wernicke's area is responsible for analysing spoken language. A patient with a lesion in this area has a so-called Wernicke's aphasia. He is able to hear language but is no longer able to understand it and therefore cannot produce any meaningful sentences any more. He talks 'word salad', like for instance: ' I then did this chingo for some hours after my dazi went through meek and been sharko'. A difficulty which occurs with Wernicke's aphasia patients is that they are often not aware of their lack of ability to speak correctly because they cannot understand what they are saying and think they are holding a normal conversation.

Certainly one of the famous "lesion" cases was that of Phineas Gage. On 13 September 1848 Gage, a railroad construction foreman, was using an iron rod to tamp an explosive charge into a body of rock when premature explosion of the charge blew the rod through his left jaw and out the top of his head. Miraculously, Gage survived, but reportedly underwent a dramatic personality change as a result of destruction of one or both of his frontal lobes. The uniqueness of Gage case (and the ethical impossibility of repeating the treatment in other patients) makes it difficult to draw generalizations from it, but it does illustrate the core idea behind the lesion method. Further problems stem from the persistent distortions in published accounts of Gage—see the Wikipedia article Phineas Gage.


CAT scanning was invented in 1972 by the British engineer Godfey N. Hounsfield and the South African (later American) physicist Alan Cromack.


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