Describe and critically assess one invasive and one non-invasive method of investigating the brain.

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Psychology Exam Questions

  1. Describe and critically assess one invasive method of investigating the brain. (12)

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.

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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 different parts of the ...

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