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Dive into the research topics where Rodrigo Riveros is active.

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Featured researches published by Rodrigo Riveros.


PLOS ONE | 2010

Applauding with Closed Hands: Neural Signature of Action-Sentence Compatibility Effects

Pia Aravena; Esteban Hurtado; Rodrigo Riveros; Juan Felipe Cardona; Facundo Manes; Agustín Ibáñez

Background Behavioral studies have provided evidence for an action–sentence compatibility effect (ACE) that suggests a coupling of motor mechanisms and action-sentence comprehension. When both processes are concurrent, the action sentence primes the actual movement, and simultaneously, the action affects comprehension. The aim of the present study was to investigate brain markers of bidirectional impact of language comprehension and motor processes. Methodology/Principal Findings Participants listened to sentences describing an action that involved an open hand, a closed hand, or no manual action. Each participant was asked to press a button to indicate his/her understanding of the sentence. Each participant was assigned a hand-shape, either closed or open, which had to be used to activate the button. There were two groups (depending on the assigned hand-shape) and three categories (compatible, incompatible and neutral) defined according to the compatibility between the response and the sentence. ACEs were found in both groups. Brain markers of semantic processing exhibited an N400-like component around the Cz electrode position. This component distinguishes between compatible and incompatible, with a greater negative deflection for incompatible. Motor response elicited a motor potential (MP) and a re-afferent potential (RAP), which are both enhanced in the compatible condition. Conclusions/Significance The present findings provide the first ACE cortical measurements of semantic processing and the motor response. N400-like effects suggest that incompatibility with motor processes interferes in sentence comprehension in a semantic fashion. Modulation of motor potentials (MP and RAP) revealed a multimodal semantic facilitation of the motor response. Both results provide neural evidence of an action-sentence bidirectional relationship. Our results suggest that ACE is not an epiphenomenal post-sentence comprehension process. In contrast, motor-language integration occurring during the verb onset supports a genuine and ongoing brain motor-language interaction.


Psychiatry Research-neuroimaging | 2012

The face and its emotion: Right N170 deficits in structural processing and early emotional discrimination in schizophrenic patients and relatives

Agustín Ibáñez; Rodrigo Riveros; Esteban Hurtado; Ezequiel Gleichgerrcht; Hugo Urquina; Eduar Herrera; Lucia Amoruso; Migdyrai Martín Reyes; Facundo Manes

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.


Schizophrenia Research | 2010

Context-sensitive social cognition is impaired in schizophrenic patients and their healthy relatives

Rodrigo Riveros; Facundo Manes; Esteban Hurtado; M. Escobar; M. Martin Reyes; Marcelo Cetkovich; Agustín Ibáñez

Social cognition performance has been extensively studied within the schizophrenic population since Frith (1992) proposed amodel relatingmentalizing deficits and symptoms of the disorder. Moreover, recent research has suggested that social cognition is also impaired in unaffected relatives. Their deficits seem to be more pronounced when highly sophisticated tests are used (Janssen et al., 2003). Fifteen clinically-stable medicated schizophrenic patients from multiplex families, fourteen healthy first-degree relatives, and eighteen controls were examined. Groups were similar in age, education, and sex distribution. Initial selection criteria for all patients were: (1) diagnosis of paranoid schizophrenia according to DSM-IV-TR criteria (APA, 2000) and confirmed with Schedules of Clinical Assessment in Neuropsychiatry (SCAN) applied to both the patients and their relatives; and (2) the presence of one or more relativeswith the diagnosis of schizophrenia (no greater than third-degree relative), evidenced by the Family Interview for Genetic Studies (FIGS). Healthy relatives had to be first-degree relatives. SCANwas applied to relatives in order to rule out any psychiatric conditions in this group. All participants were between 20 and 55 years old. Participants completed written informed consent and were paid for their participation in the study. Participants completed the Ravens Coloured Progressive Matrices, Trail Making Test, Reading theMind in the Eyes, and Faux Pas Test. Additionally, Positive and Negative Syndrome Scale (PANSS) and Calgary Depression Scale for Schizophrenia were applied to patients to characterize symptomatology and mood. Detailed information about participants, results and discussion is presented as Supplementary data. Main results (Table 1) were:


Behavioral and Brain Functions | 2011

Facial and semantic emotional interference: A pilot study on the behavioral and cortical responses to the dual valence association task

Agustín Ibáñez; Esteban Hurtado; Rodrigo Riveros; Hugo Urquina; Juan Felipe Cardona; Agustín Petroni; Alejandro Lobos-Infante; Joaquín Barutta; Sandra Baez; Facundo Manes

BackgroundIntegration of compatible or incompatible emotional valence and semantic information is an essential aspect of complex social interactions. A modified version of the Implicit Association Test (IAT) called Dual Valence Association Task (DVAT) was designed in order to measure conflict resolution processing from compatibility/incompatibly of semantic and facial valence. The DVAT involves two emotional valence evaluative tasks which elicits two forms of emotional compatible/incompatible associations (facial and semantic).MethodsBehavioural measures and Event Related Potentials were recorded while participants performed the DVAT.ResultsBehavioural data showed a robust effect that distinguished compatible/incompatible tasks. The effects of valence and contextual association (between facial and semantic stimuli) showed early discrimination in N170 of faces. The LPP component was modulated by the compatibility of the DVAT.ConclusionsResults suggest that DVAT is a robust paradigm for studying the emotional interference effect in the processing of simultaneous information from semantic and facial stimuli.


Dementia and Geriatric Cognitive Disorders | 2012

The technology - activities of daily living questionnaire: a version with a technology-related subscale

Carlos Muñoz-Neira; Oscar L. Lopez; Rodrigo Riveros; Javier Núñez-Huasaf; Patricia Flores; Andrea Slachevsky

Background: Information and communication technology (ICT) has become an increasingly important part of daily life. The ability to use technology is becoming essential for autonomous functioning in society. Current functional scales for patients with cognitive impairment do not evaluate the use of technology. The objective of this study was to develop and validate a new version of the Activities of Daily Living Questionnaire (ADLQ) that incorporates an ICT subscale. Method: A new technology-based subscale was incorporated into the Spanish version of the ADLQ (SV-ADLQ), entitled the Technology version of the ADLQ (T-ADLQ). The T-ADLQ was administered to 63 caregivers of dementia patients, 21 proxies of mild cognitive impairment patients and 44 proxies of normal elderly subjects (mean age of the sample ± SD: 73.5 ± 8.30 years). We analysed the convergent validity, internal consistency, reliability cut-off point, sensitivity and specificity of the T-ADLQ. The results of the T-ADLQ were compared to the SV-ADLQ. Results: The T-ADLQ showed significant correlations with the Mini-Mental State Examination (MMSE), the Frontal Assessment Battery (FAB) as well as other measures of functional impairment and dementia severity (MMSE: r = –0.70; FAB: r = –0.65; Functional Assessment Questionnaire: r = 0.77; Instrumental Activities of Daily Living Scale: r = –0.75; Clinical Dementia Rating Scale: r = 0.72; p < 0.001). The T-ADLQ showed a good reliability with a relatively high Cronbach’s α-coefficient (Cronbach’s α = 0.861). When considering a functional impairment cut-off point greater than 29.25%, the sensitivity and specificity of the T-ADLQ were 82 and 90%, respectively. The area under the receiver-operating characteristic curve was 0.937 for the T-ADLQ and 0.932 for the original version of the test. Conclusions: The T-ADLQ revealed adequate indicators of validity and reliability for the functional assessment of activities of daily living in dementia patients. However, the inclusion of technology items in the T-ADLQ did not improve the performance of the scale, which may reflect the lack of widespread use of technology by elderly individuals. Thus, although it appeared reasonable to add technology use questions to the ADLQ, our experience suggested that this has to be done cautiously, since the sensitivity of these additional items could vary in different populations. The T-ADLQ needs to be validated in a different population of dementia subjects.


Behavioural Neurology | 2012

The relationship of clinical, cognitive and social measures in schizophrenia: A preliminary finding combining measures in probands and relatives

David Huepe; Rodrigo Riveros; Facundo Manes; Blas Couto; Esteban Hurtado; Marcelo Cetkovich; María Josefina Escobar; Viviana Vergara; Teresa Parrao; Agustín Ibáñez

This study examines performance of schizophrenia patients, unaffected relatives and controls in social cognition, cognitive and psychiatric scales looking for possible markers of vulnerability in schizophrenia. Performance of schizophrenia patients from multiplex families, first-degree relatives, and matched controls was compared and, subsequently, discriminant analysis method was used for identifying the best predictors for group membership. By using Multigroup Discriminant Analyses on the three groups, the best predictors were PANSS, Premorbid Adjustment Scale, Faux Pas test, and a face/emotion categorizing task. This model obtained 82% correct global classification, suggesting that the combination of psychiatric scales and neuropsychological/social cognition tesks are the best approach for characterizing this disease. Although preliminary, our results suggest that social cognition tasks are robust markers of schizophrenia family impairments, and that combining clinical, social and neuropsychological measures is the best approach to asses patients and relatives vulnerability.


Neurocase | 2011

Functional relations trump implied motion in recovery from extinction: Evidence from the effects of animacy on extinction

M J Riddoch; Rodrigo Riveros; Glyn W. Humphreys

Patients with extinction show a characteristic impairment in the identification of objects when two items are presented simultaneously, typically reporting the ipsilesional item only. The effect is thought to be due to a spatial bias advantaging the ipsilesional item under conditions of competing concurrent stimulation. Action relations between objects can result in recovery from extinction as the object pair may be perceived as a single group rather than competing perceptual units. However, objects interacting together can also have implied motion. Here we test whether implied motion is necessary to generate recovery from extinction. We varied orthogonally whether animate and inanimate objects were paired together in positions related or unrelated to action. Implied motion was greater when an animate object was present than when both stimuli were inanimate. Despite this, recovery from extinction was greater when actions were shown between inanimate objects. We suggest that actions between inanimate objects are perceived more easily due to the surfaces of these stimuli being designed for functional goals (e.g., the flat surface of a hammer head is designed to hit the flattened head of a nail). Attention is sensitive to the fit between potential action and the functional properties of objects, and not just to implied motion between stimuli.


Dementia and Geriatric Cognitive Disorders | 2012

Acknowledgement to the Reviewers

Marina Boban; Branko Malojčić; Ninoslav Mimica; Sunčica Vuković; Ivan Zrilić; Patrick R. Hof; Goran Šimić; Corinne E. Fischer; Zahinoor Ismail; Tom A. Schweizer; Matthew W. Warren; Linda S. Hynan; Myron F. Weiner; Adina Zeki Al Hazzouri; Mary N. Haan; Rachel A. Whitmer; Kristine Yaffe; John Neuhaus; E. Premi; V. Garibotto; A. Alberici; B. Paghera; R. Giubbini; A. Padovani; B. Borroni; C.G. Schipke; O. Peters; I. Heuser; T. Grimmer; M.N. Sabbagh

The editor-in-chief extends her appreciation to the editorial board members and to all ad hoc reviewers whose comments and criticisms ensure the timeliness and quality of the papers published in this journal. We are especially grateful to those members of the editorial board who, after serving for many years, have retired from the board, and we look forward to the new colleagues who will join us. Finally, we thank all of you, authors and contributors, who give this journal the international standing in the research into dementing disorders that it enjoys.


Frontiers in Neurology | 2011

Effects of donepezil on behavioral manifestations of thalamic infarction: a single-case observation.

Rodrigo Riveros; Hughes Chabriat; Rodrigo Flores; Gonzalo Alvarez; Andrea Slachevsky

Objective: To examine the effect of donepezil for the treatment of cognitive and behavioral disorders associated with thalamic lesions in a 45-year-old male who suffered an infarct in the left thalamus. Background: Recent studies suggest that donepezil may improve executive functions impairments due to subcortical ischemic lesions. Method: The effects of donepezil were analyzed in a single-case of thalamic infarction with cognitive and behavioral alterations in an open label study. Results: Significant behavioral modifications related to improved performances in executive functions were observed with the treatment. Conclusion: The results suggest that donepezil may have significant effect on executive functions that can alter behavioral outcomes after thalamic infarctions.


Schizophrenia Research | 2011

When context is difficult to integrate: Cortical measures of congruency in schizophrenics and healthy relatives from multiplex families

Agustín Ibáñez; Rodrigo Riveros; Pia Aravena; Viviana Vergara; Juan Felipe Cardona; Lorna García; Esteban Hurtado; Migdyrai Martín Reyes; Joaquín Barutta; Facundo Manes

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Esteban Hurtado

Pontifical Catholic University of Chile

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Facundo Manes

National Scientific and Technical Research Council

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Pia Aravena

Diego Portales University

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John Neuhaus

University of California

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Kristine Yaffe

University of California

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