Emotion recognition

Lesion studies indicate that ACC plays a role in emotion recognition (Hornak et al., 2003). Perhaps related to ACC damage, the ability of patients with FTD to recognize negative emotions (i.e., anger, sadness, disgust) in others, facial emotional expressions is impaired, particularly when the emotions are exhibited on static faces (Keane et al. 2002; Lavenu, et al. 1999; Lough, et al. 2005). In two cross-sectional studies, fear recognition was also shown to be impaired (Lough et al. 2005; Rosen et al. 2004b). A test of identifying vocal emotion yielded similar results: angry and sad voices were poorly identified, but there were additional deficits in recognizing the sounds of happiness or surprise (Keane, et al. 2002). In patients with SD, atrophy in the right anterior temporal cortex is associated with impaired recognition of emotional facial expressions (Rosen et al., 2006).

In general, lesions studies in humans have suggested that the right hemisphere plays a dominant role in emotional processing. Patients with injury to the right hemisphere are sometimes emotionally flat, and have difficulty understanding and expressing the normal emotional signals in the voice (variations in pitch, speed, etc., called prosody) and in facial gestures (Ross, 1997). In patients with the temporal variant of frontotemporal dementia, emotional blunting is observed primarily in association with right temporal degeneration (Miller, Chang, Mena, Boone, & Lesser, 1993).