A dead rat on the street got me thinking…about neuroscience

                My second trip to SfN has begun much more auspiciously than the Glenn Lab fiasco last year. Cancelled flights and airport switches pushed our arrival back by 10 hours to San Diego, and the travel fatigue continued throughout my stay. I arrived several hours later this year than my fellow labmates and was able to attend the closing hour of the first poster session as well as 1.5 talks discussing the neurobiological underpinnings of susceptibility to neuropathologies. As Derek mentioned in his post which I read walking to the convention center, the environment at neuroscience is overwhelming, and finding your way through the maze of posters and talks towards something personally meaningful can be rather difficult; however, the talk I landed in quite accidentally only minutes after my arrival related somewhat to a seminar discussion we were having only a couple of days ago concerning a study which showed that whites had significantly more amygdala activation when viewing black faces vs. white faces, while blacks did not show similar patterns for white faces or black faces.

                The presenter I saw did a surprisingly good job compared to some talks at neuroscience I have seen in the past with a speaker droning on in a monotone advancing slides of brain images in a dimly lit room. (Yawn.) She and her colleagues use fMRI imaging to examine neurobiological underpinnings of people’s reaction to fear expressions. Her findings were quite interesting, and I feel they could shed some light on the individual differences seen in the article we were discussing for our seminar. Basically, she and her colleagues had found no specific trends for reaction to fear expressions in a group of 24 healthy subjects; however, what she did find was a close to normal distribution of reaction times across these subjects. Variance scores were plotted against many factors including scores on personality tests measuring the subjects’ “fear of uncertainty” or something along those lines. Results showed that people with high fear of uncertainty tended to react more quickly in judging a facial expression as fearful than those with lower scores on the personality test. This tendency of people who are more fearful of uncertainty to react more quickly to fearful expressions also showed less activation of the VMPFC which has long been known to play a role in social interaction. Specifically, the VMPFC mediates emotional recognition in social interaction. Activation in an area called the SGC also differed across these participants, but I am not sure of the directionality.

                The point I would like to make concerning the article on implicit bias of the amygdala in whites for black faces, is that there are possibly more factors at play contributing to these results than the article suggested. Activation of the Amygdala does not necessarily mean that the participant was “afraid,” but rather that their amygdala was attending to “uncertain” sensory information, and could have been primed for some sort of physiological reaction which may or may not have occurred (the paper was unclear). This difficulty in recognizing faces of other races happens quite early in development and could be a factor in explaining these results. Furthermore, the use of a personality inventory to assess participants in the talk I just attended was very useful in correlating their behavioral results with their imaging results, and this made their argument clear and compelling. Perhaps assessing the participants on personality characteristics such as “fear of the unfamiliar” could have strengthened the argument for implicit racial bias seen in the amygdala. As I have learned even more in the last few hours, the brain is a big beautiful mess and its activity is still such a mystery to scientists. Labeling someone as racially biased based upon their amygdala activation is not only unfair, but haphazard.


One thought on “A dead rat on the street got me thinking…about neuroscience

  1. People are educated at home with many groundless stereotypes that are too numerous to list anywhere. Some of them will be color related.
    No one has to accept the output of the amygdala as rational in any case.
    That is what the cortex is for as we all understand so the case is not irrational prompts but how we choose to handle them in a given set of circumstances.
    As long as adults indoctrinate children with racism this will be an ongoing problem.In the USA another 100 years might not be enough time.


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