Beyond threat: Amygdala reactivity across multiple expressions of facial affect

A decline in the ability to process facial expression of emotions has been reported in individuals with Alzheimer's disease (AD). However, the low number of participants and the lack of diversity in the tasks being used in previous studies leaves a gap in our knowledge about this issue. We recruited 169 participants including healthy older adults (HOA), participants with mild cognitive impairment (MCI) and AD patients at different stages of the disease (mild to moderate). Four tasks including recognition, selection, matching and declarative knowledge about facial expression of emotions were used. Face identification was used as a control task. Our results revealed that compared with HOA, MCI participants did not show any significant deficits in none of the tasks. AD patients did not show any impairment in the control task. However, they were impaired in the processing of facial expression of negative emotions across all four affective tasks. Interestingly, recognition and selection of happiness were intact in AD patients at the mild stage of the disease. Our findings suggest that despite the pathology affecting distributed areas in the brain, the less challenging aspects (recognition and selection) of the ability to process the facial expression of happiness were preserved at the early stage of the disease. By recruiting a large number of participants using several different tasks our study provides a comprehensive picture of the disorders of facial emotion processing in Alzheimer's Disease. Our findings have significant implications for improving the AD patients' quality of life and the quality of their social interaction with others. Future studies might start to investigate the processing of emotions in AD patients in other modalities rather than visual.

The neurobiological underpinnings of intermittent explosive disorder (IED) are traditionally linked to deficiencies in the serotonergic system. In this study, we investigated the effects of escitalopram, a selective serotonin reuptake inhibitor (SSRI), on brain activation during face processing. We expected that escitalopram would reduce amygdala activity in IED and in addition, we explored the effect in other social-emotional-related brain regions. A total of 17 subjects with current IED and 14 healthy controls participated in a randomized, double-blind, placebo-controlled, counterbalanced fMRI face processing study. The analysis focused on the faces compared to a fixation baseline contrast, and a factorial model with Group as between-subject and Drug as within-subject factor was tested. Group × Drug interaction effects were found in the amygdala (small volume corrected) and the left temporal parietal junction (TPJ; whole-brain corrected). Escitalopram increased amygdala activation in controls, but surprisingly not in IED. However, the TPJ showed increased activity in IED on escitalopram compared with placebo. The TPJ is associated with social-cognitive processes, such as perspective taking and empathy. The TPJ findings suggest that SSRI administration may reduce aggressive tendencies towards other people by enhancing these social-cognitive processes. Future research should further elucidate the long-term effects of SSRIs on various social-emotional tasks in IED.

The goal of this study was to examine behavioral and electrophysiological correlates of involuntary orienting toward rapidly presented angry faces in non-anxious, healthy adults using a dot-probe task in conjunction with high-density event-related potentials and a distributed source localization technique. Consistent with previous studies, participants showed hypervigilance toward angry faces, as indexed by facilitated response time for validly cued probes following angry faces and an enhanced P1 component. An opposite pattern was found for happy faces suggesting that attention was directed toward the relatively more threatening stimuli within the visual field (neutral faces). Source localization of the P1 effect for angry faces indicated increased activity within the anterior cingulate cortex, possibly reflecting conflict experienced during invalidly cued trials. No modulation of the early C1 component was found for affect or spatial attention. Furthermore, the face-sensitive N170 was not modulated by emotional expression. Results suggest that the earliest modulation of spatial attention by face stimuli is manifested in the P1 component, and provide insights about mechanisms underlying attentional orienting toward cues of threat and social disapproval. Keywords spatial attention; anger; face perception; event-related potentials; source localization Electrophysiological correlates of spatial orienting towards angry faces: A source localization studyPerception of the human face, as well as the social cues derived from it, is central to social interaction and in the communication of threat (Argyle, 1983), and occurs rapidly, within 100 ms of presentation (e.g., Liu, Harris, & Kanwisher, 2002). For healthy individuals, visual scanpaths of the human face are directed to salient features that define facial emotional expressions such as the mouth and eyes (Walker-Smith, Gale & Findlay, 1977;Mertens, Please address all correspondence to: Diego A. Pizzagalli, Ph.D., Department of Psychology, Harvard University, 1220 William James Hall, 33 Kirkland Street, Cambridge, MA 02138, USA, Phone: +1-617-496-8896, Fax: +1-617-495-3728, Email: dap@wjh.harvard.edu. Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.Disclosures Dr. Pizzagalli has received research support from GlaxoSmithKline and Merck & Co., Inc. for projects unrelated to the present study. Dr. Hofmann is a paid consultant by Organon for issues and projects unrelated to this study. Drs. Santesso and Meuret as well as Mr. Mueller, Ratner, and Roesch report no competing interests. NIH Public Access Author ManuscriptNeurops...