Browsing by Author "Gleichgerrcht, Ezequiel"

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    Early neural markers of implicit attitudes: N170 modulated by intergroup and evaluative contexts in IAT
    (2010) Ibáñez, Agustín; Gleichgerrcht, Ezequiel; Hurtado, Esteban; González, Ramiro; Haye M., Andrés; Manes, Facundo F.
    The Implicit Association Test (IAT) is the most popular measure to evaluate implicit attitudes. Nevertheless, its neural correlates are not yet fully understood. We examined event related potentials (ERPs) in response to face- and word processing while indigenous and non-indigenous participants performed an IAT displaying faces (ingroup and outgroup members) and words (positive and negative valence) as targets of category judgments. The N170 component was modulated by valence of words and by ingroup/outgroup face categorization. Contextual effects (face–words implicitly associated in the task) had an influence on the N170 amplitude modulation. On the one hand, in face categorization, right N170 showed differences according to the association between social categories of faces and affective valence of words. On the other, in word categorization, left N170 presented a similar modulation when the task implied a negative-valence associated with ingroup faces. Only indigenous participants showed a significant IAT effect and N170 differences. Our results demonstrate an early ERP blending of stimuli processing with both intergroup and evaluative contexts, suggesting an integration of contextual information related to intergroup attitudes during the early stages of word and face processing. To our knowledge, this is the first report of early ERPs during an ethnicity IAT, opening a new branch of exchange between social neuroscience and social psychology of attitudes.
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    The face and its emotion: Right N170 deficits in structural processing and early emotional discrimination in schizophrenic patients and relatives
    (ELSEVIER IRELAND LTD, 2012) Ibanez, Agustin; Riveros, Rodrigo; Hurtado, Esteban; Gleichgerrcht, Ezequiel; Urquina, Hugo; Herrera, Eduar; Amoruso, Lucia; Martin Reyes, Migdyrai; Manes, Facundo
    Previous studies have reported facial emotion recognition impairments in schizophrenic patients, as well as abnormalities in the N170 component of the event-related potential. Current research on schizophrenia highlights the importance of complexly-inherited brain-based deficits. In order to examine the N170 markers of face structural and emotional processing, DSM-IV diagnosed schizophrenia probands (n = 13), unaffected first-degree relatives from multiplex families (n = 13), and control subjects (n = 13) matched by age, gender and educational level, performed a categorization task which involved words and faces with positive and negative valence. The N170 component, while present in relatives and control subjects, was reduced in patients, not only for faces, but also for face-word differences, suggesting a deficit in structural processing of stimuli. Control subjects showed N170 modulation according to the valence of facial stimuli. However, this discrimination effect was found to be reduced both in patients and relatives. This is the first report showing N170 valence deficits in relatives. Our results suggest a generalized deficit affecting the structural encoding of faces in patients, as well as the emotion discrimination both in patients and relatives. Finally, these findings lend support to the notion that cortical markers of facial discrimination can be validly considered as vulnerability markers. (C) 2011 Elsevier Ireland Ltd. All rights reserved.