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کد مقاله | سال انتشار | تعداد صفحات مقاله انگلیسی |
---|---|---|
30224 | 2015 | 7 صفحه PDF |
Publisher : Elsevier - Science Direct (الزویر - ساینس دایرکت)
Journal : Schizophrenia Research, Volume 164, Issues 1–3, May 2015, Pages 203–209
چکیده انگلیسی
Background Social impairments are a hallmark feature of schizophrenia and are a key predictor of functional disability. Deficits in social information processing likely underlie social impairment; however, this relationship is understudied. We previously demonstrated that patients with schizophrenia fail to habituate to neutral faces, providing evidence for an alteration in basic social information processing. It remains unknown whether patients with schizophrenia also show deficits in processing of more complex social information. Out-group bias provides an excellent opportunity to test complex social information processing because the bias requires basic face processing skills, the ability to discriminate between groups, as well as the ability to categorize oneself into a salient social group. Methods Study participants were 23 patients with schizophrenia and 21 controls. Using functional magnetic resonance imaging, habituation of response to 120 s of repeated presentations of faces was assessed in participants who viewed either same-gender faces or opposite-gender faces. The interaction between face gender (same/opposite) and group was examined in three key regions: amygdala, hippocampus, and visual cortex. Social impairment was measured using the PANSS and correlations between social impairment and out-group effect (main effect of face type) were performed in patients. Results Patients with schizophrenia had aberrant neural responses to opposite-gender faces (interaction, p < .05 corrected). Healthy controls showed an immediate heightened response to opposite-gender faces relative to same-gender faces; but in patients this effect was substantially delayed (~ 70 s). In patients with schizophrenia, the out-group bias was significantly correlated with social impairment. Patients with no social impairment showed a heightened neural response to opposite-gender faces after 30 s, whereas patients with mild–moderate social impairment failed to ever show a heightened response. Conclusion Alterations in neural responses during out-group processing predicted degree of social impairment in patients with schizophrenia; thus, neural responses to opposite-gender faces may provide a novel measure for studies of treatment response and disease outcome.
مقدمه انگلیسی
Deficits in the processing of social information are paramount in schizophrenia and are thought to underlie the observable deficits in social impairment. A growing body of research demonstrates that patients with schizophrenia have deficits in social information processing (Lee et al., 2013). For example, patients have a well-established deficit in emotion perception, typically demonstrated as an impaired ability to recognize or label emotional facial expressions (Chan et al., 2010), which is accompanied by reduced activation in several brain regions implicated in social and emotional information processing (Li et al., 2010). However, emotional faces confound emotion processing with processing of the social information inherent in faces. To directly investigate neural processing of a socially relevant stimulus in patients with schizophrenia, we recently measured neural response to repeated presentation of neutral faces (Williams et al., 2013). Decreased responding to repeated presentations of a stimulus over time, or habituation, is one of the most basic learning processes and provides an ideal opportunity to observe social information processing. In controls, neural responses to repeated faces habituated over time; however, patients failed to show habituation. Importantly, the habituation deficits were specific to faces as they were not observed when participants viewed neutral objects, providing compelling evidence for a basic deficit in social information processing. Failure to habituate may represent a trans-diagnostic biomarker for social impairments as other groups characterized by social deficits, including autism and high social anxiety, also show habituation deficits to social stimuli (Kleinhans et al., 2009, Blackford et al., 2013 and Swartz et al., 2013). Human faces convey a multitude of information critical for social interactions. In addition to emotion, faces provide salient information about identity, race, and gender. This additional information is used to quickly categorize others according to salient social groups. An interesting aspect of both race and gender is that humans show “out-group” biases; that is, behaviors and neural responses that differ when viewing someone that differs from oneself on either race (Hart et al., 2000 and Olsson et al., 2005) or gender (Shapiro and Penrod, 1986, Shaw and Skolnick, 1994 and Wright and Sladden, 2003). For gender bias, recognition memory is lower for out-group faces relative to in-group faces (Shaw and Skolnick, 1994). The out-group phenomenon suggests that face properties such as gender elicit a level of social information processing that goes beyond basic face processing. Out-group bias likely requires several abilities, including the ability to discriminate between groups (Dunham et al., 2013) and to categorize oneself in to a salient social group (Turner et al., 1987). Patients with schizophrenia have intact gender discrimination (Bediou et al., 2005) but models of schizophrenia (i.e. ipseity-disturbance model) propose that patients with schizophrenia lack a consciousness of self (Nelson et al., 2014), which may produce deficits in self-categorization and social impairments. The neutral faces employed in our previous study did not vary in their race (all Caucasian), but did vary in gender, such that participants viewed faces of either the same or opposite gender to themselves. This provides a unique opportunity to test for differences in the neural processing of complex social information in schizophrenia and the impact on social functioning. In the present study, we analyzed fMRI habituation data with a focus on gender out-group effects in schizophrenia. We hypothesized that patients with schizophrenia would fail to display the typical neural pattern of out-group bias—delayed habituation to opposite-gender faces. We further predicted that within patients, deficits in social information processing would predict social impairment.