Recognition of facial emotion in nine individuals with bilateral amygdala damage

     In this study of nine patients with bilateral amygdala damage, researchers found that lesions to the amygdala significantly impair patients' recognition of fearful faces compared to control and other brain-damaged participants. This study supports the notion that the amydala plays a role in detection of fear and threat on the faces of other people. An interesting aspect of this study was that even though on the whole, patients with bilateral amygdala damage were less likely to recognize the emotion of fear, there were a couple patients that had no trouble doing so, and these particular patients did not differ from the others in terms of lesion size, age, or IQ. According to the researchers, "One plausible explanation could be that (a) the amygdala is activated when processing facial expressions of fear, but that (b) it may not be essential to give normal performance on recognition tasks, because the subject may adopt alternate strategies that allow retrieval of knowledge about the emotion using anatomical routes other than the amygdala" (p.1116). This comment highlights the complicated nature of neuroscience. Although a particular region of the brain may be implicated in certain behavioral responses, it doesn't mean that it is necessary for those responses to occur, at least not in every person.

R. Adolphsa, D. Tranela, S. Hamannb, A.W. Youngc, A.J. Calderd, E.A. Phelpse,
A. Andersone, G.P. Leef, A.R. Damasioa (1999). Recognition of facial emotion in nine individuals with bilateral amygdala damage. Neuropsychologia 37, 1111-1117.