Recent Study Suggest it's True... Size Does Matter

          What sets apart psychopathic patients aside from nonpsychopath patients? Dr. Newman discussed the “low fear” hypothesis, which attempts to explain psychopathy during our seminar. Previous studies have found that the amygdala plays an important role in psychopathy. This has been determined because studies have found that psychopathic patients have low fear. With the amygdala being responsible for inducing fear, studies have shown that low fear is caused by an amygdala-mediated deficit. The amygdala-mediated deficient causes poor passive avoidance, or in other words an inhibition of punished responses, weak electrodermal activity in response to threat and/or punishment cues, deficits in emotion-modulated startle during picture viewing, deficits in fear conditioning, and reduced amygdala activation. Dr. Newman specifically talked to our class about top-down goal-directed behavior being crucial to the study of psychopathy. Attention mediates the low fear deficits seen in psychopathic patients, especially during goal-oriented tasks.

            A new study, published in May of 2013, has found that the size of the amygdala can play an important role in violent and aggressive behavior from childhood to early adulthood. This research used 56 men who had already been involved in a previous study that involved measuring unsociable and criminal behavior from childhood to early adulthood. About one third of these men had a history of peristent serious violence, about one third had momentary history of serious violence, and about one third had no history of serious violence. After understanding the different levels of violence these men have partaken in, structural MRI imaging was used to measure the amygdalae of each of these men’s brains. The results showed that men with smaller amygdalae were more likely to partake in violent and aggressive behaviors. Men with smaller amygdalae also have been shown to have characteristics that are related to psychopathy.

            This recent study is a great addition to what is already known about the amygdala’s role in psychopathy. This is the first study that has looked at the volume of the amygdala to try to explain psychopathic behavior. From the various research gained over the years, we have learned that several factors come into play regarding psychopathy, and size of the amygdala may be one.

References:

Arehart-Treichel, Joan. "Amygdala Size May Give Clue to Violence Risk." Psychiatric

News. The American Psychiatric Association, 11 July 2013. Web. 10 Dec. 2013.

Larson, Christine L., Arielle R. Baskin-Sommers, Daniel M. Stout, Nicholas L.

Balderston, John J. Curtin, and Douglas H. Schultz. "The Interplay of Attention

and Emotion: Top-down Attention Modulates Amygdala Activation in

Psychopathy." Cognitive, Affective, & Behavioral Neuroscience 13.2 (2013): n. pag. Springer. Web.

Newman, Joseph P., and Arielle R. Baskin-Sommers. “Early Selective Attention

Abnormalities in Psychopathy: Implications for Self-Regulation.” Cognitive Neuroscience of Attention. By Michael I. Posner. New York: Guilford, 2011. 421-440.