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Brief monocular deprivation as an assay of short-term visual sensory plasticity in schizophrenia – “the binocular effect”
Neurophysiologie Clinique/Clinical Neurophysiology (2013) 43, 67—80
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ANT BURGUNDY NEUROMEETING 2013, BEAUNE, FRANCE
Abstracts Résumés des communications
Session: Cognition CO1
Brief monocular deprivation as an assay of short-term visual sensory plasticity in schizophrenia — ‘‘the binocular effect’’ J.J. Foxe a,b,c,d,∗ , S. Yeap a,b , V.M. Leavitt a,c The Cognitive Neurophysiology Laboratory, Nathan S. Kline Institute for Psychiatric Research, USA b The Cognitive Neurophysiology Laboratory, St. Vincent’s Hospital, Ireland c Program in Neuropsychology, Department of Psychology, Queens College of the City University of New York, New York, USA d The Sheryl and Daniel R. Tishman Cognitive Neurophysiology Laboratory, Children’s Evaluation and Rehabilitation Center (CERC), Departments of Pediatrics & Neuroscience, Albert Einstein College of Medicine, USA ∗ Corresponding author. E-mail address: [email protected] (J.J. Foxe)
a
Visual sensory processing deficits are consistently observed in schizophrenia, with clear amplitude reductions in the early visual evoked potential (VEP), particularly evident during the processing timeframe of the first positive component (the P1). Similar deficits are seen in unaffected first-degree relatives and drug-naïve firstepisode patients, pointing to these deficits as endophenotypic, with possible utility as measures for risk-assessment. However, large inter-individual variability in baseline measures of these deficits limits their diagnostic utility. Here, there were two main goals: — to leverage second-order ‘‘dynamic’’ effects of the P1-deficit in an attempt to improve sensitivity of this measure; — to better understand the functional implications of visual sensory deficits in schizophrenia. A paradigm utilizing brief periods of monocular deprivation was employed, since this is known to induce short-term amplitude changes in the processing timeframe of the P1; i.e. short-term plasticity. Twenty patients and 20 age-matched non-psychiatric control participants participated in this study. VEP were recorded during binocular viewing, and were compared to the sum of VEP
0987-7053/$ – see front matter
responses during monocular viewing (i.e. Left-eye + Right-eye). A clear P1-deficit was replicated in patients during binocular viewing. Additionally, under monocular conditions, controls exhibited an effect that patients failed to demonstrate. That is, the summed VEP amplitude of the two monocular recordings was robustly greater than the amplitude elicited binocularly during the P1 processing timeframe. In patients, this ‘‘binocular effect’’ was absent. These results suggest that short-term compensatory mechanisms that allow healthy individuals to generate robust VEP in the context of monocular deprivation are not effectively activated in patients with schizophrenia. http://dx.doi.org/10.1016/j.neucli.2012.11.002 CO2
Neural correlates for vanishing point perception A. Basu , S. Ghosh Jadavpur University, School of Cognitive Science, Kolkata, India E-mail addresses: [email protected] (A. Basu), [email protected] (S. Ghosh) Often, multiple objects around us are projected in the brain simultaneously. These objects build an interactive interface where individual objects are related to the context, e.g., a table, many chairs, a projector, and corners of the room; or a road through high rises in the city, taking right or left turn. Here abstract lines intersecting at the vanishing points along with multiple objects provide information about perspective of the scene. At what time in the brain are these vanishing points perceived? What is the time course of sensitivity to such abstract interactions, which allow detection of change in perspective or match between two near simultaneous perspectives? Here, we report that change in perspective based on the change in vanishing point elicits greater activity in the lateral, parietal and occipital regions during the time course of signal around 100—120 ms to the presentation of the image. Change in perspectives increased this gain from the standard image which had a fixed vanishing point at the centre of the image. Further we report that increased activity in parietal and fronto-central cortex is seen when two near simultaneous images with opposite locations of the vanishing points are presented. Abstract relations such as vanishing point perception are thus likely achieved simultaneously with object shape and scene perception. Change in vanishing point induces a
Disponible en ligne sur
www.sciencedirect.com
ANT BURGUNDY NEUROMEETING 2013, BEAUNE, FRANCE
Abstracts Résumés des communications
Session: Cognition CO1
Brief monocular deprivation as an assay of short-term visual sensory plasticity in schizophrenia — ‘‘the binocular effect’’ J.J. Foxe a,b,c,d,∗ , S. Yeap a,b , V.M. Leavitt a,c The Cognitive Neurophysiology Laboratory, Nathan S. Kline Institute for Psychiatric Research, USA b The Cognitive Neurophysiology Laboratory, St. Vincent’s Hospital, Ireland c Program in Neuropsychology, Department of Psychology, Queens College of the City University of New York, New York, USA d The Sheryl and Daniel R. Tishman Cognitive Neurophysiology Laboratory, Children’s Evaluation and Rehabilitation Center (CERC), Departments of Pediatrics & Neuroscience, Albert Einstein College of Medicine, USA ∗ Corresponding author. E-mail address: [email protected] (J.J. Foxe)
a
Visual sensory processing deficits are consistently observed in schizophrenia, with clear amplitude reductions in the early visual evoked potential (VEP), particularly evident during the processing timeframe of the first positive component (the P1). Similar deficits are seen in unaffected first-degree relatives and drug-naïve firstepisode patients, pointing to these deficits as endophenotypic, with possible utility as measures for risk-assessment. However, large inter-individual variability in baseline measures of these deficits limits their diagnostic utility. Here, there were two main goals: — to leverage second-order ‘‘dynamic’’ effects of the P1-deficit in an attempt to improve sensitivity of this measure; — to better understand the functional implications of visual sensory deficits in schizophrenia. A paradigm utilizing brief periods of monocular deprivation was employed, since this is known to induce short-term amplitude changes in the processing timeframe of the P1; i.e. short-term plasticity. Twenty patients and 20 age-matched non-psychiatric control participants participated in this study. VEP were recorded during binocular viewing, and were compared to the sum of VEP
0987-7053/$ – see front matter
responses during monocular viewing (i.e. Left-eye + Right-eye). A clear P1-deficit was replicated in patients during binocular viewing. Additionally, under monocular conditions, controls exhibited an effect that patients failed to demonstrate. That is, the summed VEP amplitude of the two monocular recordings was robustly greater than the amplitude elicited binocularly during the P1 processing timeframe. In patients, this ‘‘binocular effect’’ was absent. These results suggest that short-term compensatory mechanisms that allow healthy individuals to generate robust VEP in the context of monocular deprivation are not effectively activated in patients with schizophrenia. http://dx.doi.org/10.1016/j.neucli.2012.11.002 CO2
Neural correlates for vanishing point perception A. Basu , S. Ghosh Jadavpur University, School of Cognitive Science, Kolkata, India E-mail addresses: [email protected] (A. Basu), [email protected] (S. Ghosh) Often, multiple objects around us are projected in the brain simultaneously. These objects build an interactive interface where individual objects are related to the context, e.g., a table, many chairs, a projector, and corners of the room; or a road through high rises in the city, taking right or left turn. Here abstract lines intersecting at the vanishing points along with multiple objects provide information about perspective of the scene. At what time in the brain are these vanishing points perceived? What is the time course of sensitivity to such abstract interactions, which allow detection of change in perspective or match between two near simultaneous perspectives? Here, we report that change in perspective based on the change in vanishing point elicits greater activity in the lateral, parietal and occipital regions during the time course of signal around 100—120 ms to the presentation of the image. Change in perspectives increased this gain from the standard image which had a fixed vanishing point at the centre of the image. Further we report that increased activity in parietal and fronto-central cortex is seen when two near simultaneous images with opposite locations of the vanishing points are presented. Abstract relations such as vanishing point perception are thus likely achieved simultaneously with object shape and scene perception. Change in vanishing point induces a