This weeks reading is composed of detailed literature that illustrate how scientist have been trying to map the brain. There has been much focus on trying to match specific elements of the human mind, such as memory and emotions, to specific regions of the brain. This has been accomplished by studying individuals who have had brain trauma or by inducing trauma with brain lesions and trying to match up the mental defect with the location of the brain damage.
More recent advances in neuroimaging have provided scientist with fMRI and PET scans to monitor brain activity in the presence of stimuli. An fMRI measures increases in cerebral blood flow in specific regions, which may not be caused by metabolic demands as it initially appears to be, but instead driven by the presence of neurotransmitters such as glutamate. PET scans on the other hand use a radioactive isotope that decays over time and releases positrons that are detected through out the body.
In the review article “Functional Neuroimaging Studies of Human Emotions” they use these methods to determine if there are patterns of brain activation when they elicit different emotions with a range of emotional tasks. Though out the article they summarize how specific regions are active when specific emotions are induced. The amygdala for instance is shown to be involved in “fear-related responding” where it is the most active when participants have been shown fearful faces, even if they are unconscious of the fact that they are seeing fearful faces. I wonder though how the researchers can be so certain that just by having the participants classify the faces by gender rather than emotion that they are assuring unconscious perception of the facial expressions. Yet from their technique they deduced that perhaps the amygdala might be responsible for signaling a threat instead of evoking fear. The description of their results brings to mind how only certain areas of the brain, and even certain areas of the amygdala are activated when stimulus is conscious or unconscious in the subject. There seems to be conflicting evidence around whether if the amygdala is under a “top down control” where activity in this region is dependent on the amount of attention the participant pays to the stimuli and hence would help define its precise role in the emotion fear.
My problem with reading this article is that it brings to light the difficulty with identifying a specific region as being responsible for a particular mental faculty. As stated in the conclusion of “The Emotion of Fear”, researchers need to put less energy in identifying a specific region with a specific function, and more with identifying circuits in the brain as they run through specific brain regions. As it was seen with Phineas Gage and later Damasio’s patient Elliot, it was almost impossible to locate the specific problem that Elliot had when it came to decision-making. That might be why doctors thought that the problem was not physical but instead psychological. It was obvious that the tumor had caused brain damage in a general location, but his actual mental defect was difficult to locate as it seemed that somewhere along the decision making process Elliot lacked a tool needed to make a decision that was in his best interest. As the third chapter of Damasio’s story illustrates, it was a frustrating task to pinpoint Elliot’s problem with the use of tests commonly used by psychologists. It seemed that the tests were unable to properly identify the problem he was having with real life scenarios, hence making his case hard to prove as they attempt to show it is a physical disability.
What Damasio did conclude was that Elliot had a “reduction in emotional reactivity and feelings”(p.51) that effected his reasoning and decision making processes. This very concept goes against some basics in western philosophy such as the difference between reason and emotions. What I need to understand now is how emotions help us make proper decisions when all this time I thought it would inhibit my ability to make decisions.
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2 comments:
I, like Margot, am skeptical of the studies that are done on humans in search of information on the location and understanding of emotions in the brain. Although studies like the ones we read for class this week are one of the only ways in which we can study these things, I question the methods and their objectiveness. Are the subjects aware of what the researchers are aiming to prove/find out? if so, wouldn't one be led to believe that that affects their performance during the test? If an individual knows the test is about emotional response, I would assume that their emotional responses would consequently be higher, or lower, as they might be more consciously feeling or
thinking about their emotions. Also, it seems as though every psychologist, or individuals in other areas of study hopeing to illicit certain information from a series of tests, could formulate a test that will support their own theory. I think the concept touched upon in some of the readings, that maybe the questions about emotions need to be modified, is tactful, and would perhaps derive more salient answers or leads.
As Margot indicated, the "Functional Neuroimaging Studies of Human Emotions" is a helpful step to understanding more about the activity of the brain in relation to various emotions. However, I too had difficulty with the fact that the article doesn't focus on the circuitry of the brain activity. It seems to be stuck on focusing on one region of the brain at a time, as opposed to looking at the whole picture.
Additionally, I think it's a mistake that this article doesn't recognize the significance of how these studies effect the participants. How can these results not be somewhat "skewed" when the particpants (albeit, only sometimes) are conscious of the fact that they're being studied? Certainly this must effect the participants' responses.
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