It allows neuroinvestigators to locate the region where the brain activity is taking place using powerfull magnets to measure small changes in the brains blood oxygenation level that occur while a task is performed. Through this non-invasive technology, investigators can get a dynamic picture of what is happening in specific areas of the active, working brain by looking at changes in the oxi-hemoglobin flow to the head. The hemoglobin has different magnetic characteristics depending on if it is oxygenated or not ( Buxton, 2002).
The fmri technology permits these differences in the brain to be seen. This process relates to the energy released by the brains neurons within a specific area of the brain. The powerfull magnets stimulate the atoms and molecules in the blood that flows to the brain cells. The stronger the magnet used, the higher the resolution of brain images. In addition, functional mri produces no ionizing radiation, so potential risks to subjects or patients are reduced ( Buxton, 2002).
The fmri in research is used in combination with structural magnetic resonance imaging (mri), which accommondates an anatomical bottom line, functional mri allows optimal spatial resolution during an activity. These images allow researchers to compare a healthy subject to a patient with a neurological disease or disorder. Investigators can then acquire information from comparing the differences between the two groups. In addition, fmri combined with magnetoencephalography (meg), which provides temporal dimension of brain activity, gives investigators further knowledge for the basic functions of the brain ( Veitz, 1994).
An fmri experiment usually lasts between 15 minutes to one hour. Depending on the purpose of the study, participants may watch movies, hear sounds, smell odors, perform cognitive tasks, such as memorization or imagination, press buttons ( as in Greens experiment), or perform other tasks. Subjects are asked to stay still to prevent movement from disturbing measurements. Researchers are required to give detailed instructions and descriptions of the experiment plan to each participant that must sign a consent form before the experiment. Safety is a very important issue in all experiments involving fmri, so participants must ensure that they are able to enter the fmri environment.
Functional mri studies can give researchers beneficial comprehension into the dysfunctional brain regarding neurological disorders and diseases such as schizophrenia, mental retardation, stroke, apraxia and alzheimers disease ( Tanner, 2007).
The Green and colleagues study aimed to investigate the emotional engagement in moral judgment with the use of functional magnetic resonance imaging technology. Participants were presented 60 dilemmas sheared to moral personal, moral impersonal and non moral. Then they were asked to make a judgment about the congruousness of the action and categorize it to “ appropriate” or “ inappropriate” by pressing one out of two buttons( Greene et al, 2001).
As it was indicated by the findings, the areas of the brain involved in emotion were more active as participants were presented a moral personal dilemma compared to the activation levels when presented a non moral or moral impersonal dilemma. In contrary, the levels of activation in the areas associated with the working memory were significantly lower in moral personal dilemmas. In addition, the reaction time, when a participant responded “ appropriate” to a moral personal dilemma, was remarkably longer which suggest that an emotional conflict was taking place ( Greene et al, 2001).
In conclusion, the findings of the study indicate that emotional responses have a strong impact on moral judgment, as it is shown by the paradigm of the trolley and footbridge dilemma, that although have the same outcome differ in the direction of the action and the emotional involvement of the individual.
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REFERENCES
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Buxton, R. ( 2002). Introduction to functional magnetic resonance imaging. Retrieved: December 5, 2009, from: http/books.google.gr
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Greene, J. D., Sommerville, R. B., Nystrom, L. E., Darley, J. M.,& Cohen, J. D. (2001). An fmri investigation of emotional engagement in moral judgment. Science, 293 (5537), 2105-2108.
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Tanner, J. (2007). The 3D brain. Retrieved: December 6, 2009, from: http/www.brainybehavior.com
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Veitz, J. (1994). Functional magnetic resonance imaging of the brain. Retrieved: December 5, 2009, from: http/www.ucbi.ulm.gov.
