Critical Assessment of an Invasive Method of Investigating the Brain

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Critical Assessment of an Invasive Method of Investigating the Brain There are many different invasive ways of investigating thee brain including chemical stimulation, ablation and lesioning. All invasive methods artificially stimulate, and actually affect the brain. For my example I am going to look at electrical stimulation. The first person to study electrical stimulation on the brain was by Olds and Milner in 1954. They applied a weak current to the pleasure centre of the brain to a number of rats using small electrodes. The rats themselves could trigger the electrical stimulation themselves by pressing a lever. They found that apart from eating and sleeping the rats would press the lever for hours of end. This was very important research at the time and showed how electrical impulses affect the brain, but it has a number of weaknesses. It is difficult to generalise these findings to humans. As we have conscious thought, and our brains are much more complex. Therefore what affects a rat's brain may have no effect, or even increased affect on a human brain. The first person to study how electrical currents effected the brains of humans was Penfield in 1958. He operated on people whom had severe brain tumours or epilepsy. He decided to carry out an experiment on a group of his patients (with their consent) into how electrical stimulation affects the brain. He gave his patients small electrical shocks to various parts of their cerebral cortex during the operations and asked the patients to report what they experienced (as the brain has no pain receptors the patients were fully awake). He found that when he stimulated differen... ... middle of paper ... ... (several areas affected). This can help a doctor decide if drugs are an appropriate treatment or whether neurosurgery might help. Other people have used EEG in similar ways to the above. Othmer et al (95) used EEG as a biofeedback for improving Attention Deficit Hyperactivity Disorder (ADHD) and specific learning difficulties. Although EEG are a very useful and important way of investigating the brain there are a number of disadvantages and problems. The scans can only measure the surface electrical activity of the brain and not the deeper activity (which may be important in a number of syndromes such as epilepsy). Also it is a very broad and wide-ranging scan. Although it can show whether a persons brain activity is normal or not, it cannot specifically pinpoint the region of the brain producing this activity.

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