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159. Emotional face processing in bulimia nervosa: An ERP and source localization study
Society Proceedings / Clinical Neurophysiology 120 (2009) e9–e88
nial magnetic stimulation (er-dpTMS). Subjects were instructed to execute brisk right index finger abduction after a Go-signal. ErdpTMS was delivered during movement preparation at four time points adjusted to the individual reaction time (20%, 50%, 80%, 95% of RT). The test pulse was applied over the left primary motor cortex (M1) and the conditioning pulse either over right M1 (M1-M1) or right premotor cortex (PMC-M1). Results: RTs were comparable in elderly and young subjects (195 ± 20 ms vs. 185 ± 9 ms; p = 0,2). Repeated measures analysis of variance revealed a significant interaction of time by condition (M1-M1, PMC-M1) for both young (p = 0,014; Fig. 1a) and elderly subjects (p = 0,015; Fig. 1b) explained by early interhemispheric facilitation during PMC-M1, whereas M1-M1 showed early inhibition with continuous release of inhibition towards movement onset. The significant interaction of time by group (young, elderly) yielded significance for PMC-M1 (p = 0,013; Fig. 2a), but not for M1-M1 (p = 0,412; Fig. 2b). Young subjects exhibited PMC-M1 facilitation in a very early time frame during movement preparation, whereas the elderly showed early inhibition for PMC-M1 (20% RT) and a delay of interhemispheric facilitation with its maximum after 80% of RT. Discussion: The results are in line with previous EEG, MEG, TMS and combined fMRI–TMS studies showing early ipsilateral involvement of premotor cortex in motor control of the contralateral limb. The new and central finding is that ageing appears to affect interhemispheric interaction in higher-order motor regions, such as the PMC. It is noteworthy that interhemispheric interactions between primary motor areas did not differ between age groups. It can be speculated that in the motor system higher-order regions are more and earlier involved in ageing processes than primary areas as demonstrated in other cognitive domains. doi:10.1016/j.clinph.2008.07.156
159. Emotional face processing in bulimia nervosa: An ERP and source localization study—N. Kühnpast 1, O. Pollatos 2,3, R. Schandry 3 (1 M. Sc. Program Neuro-Cognitive Psychology, LudwigMaximilians-Universität, München, Germany, 2 Neurologische Klinik und Poliklinik, Ludwig-Maximilians-Universität, München, Germany, 3 Department Psycholgie, Ludwig-MaximiliansUniversität, München, Germany) Objective: Empirical evidence suggests substantial deficits regarding emotion recognition in bulimia nervosa (BN). However, the nature of this impairment is the subject of ongoing research. The aim of this study was to investigate the processing of emotional faces in patients with BN. Methods: Event-related potentials (ERPs) were recorded from 22 female patients with BN and 22 matched healthy controls while viewing neutral, happy, fearful, and angry facial expressions, and were further analysed by using the brain electrical source localization method (BESA). Subjects’ facial recognition performance was tested separately in a categorization task. In addition, emotion identification skills were assessed with the Toronto Alexithymia Scale (TAS) and the Eating Disorder Inventory (EDI subscale Interoceptive Awareness). Results: BN patients reported greater difficulty in identifying their own feelings as well as in the regulation of emotional states. Although performance in the categorization task was comparable in BN and controls, the present ERP data demonstrate significant differences at the post-perceptual level of emotional face processing. While early processes of structural encoding, as indexed by the N170, were found to be intact, BN patients had a significant reduction of N2 amplitudes and showed higher P3 amplitudes in response to facial stimuli than healthy subjects. Furthermore, a source analy-
e67
sis in the time interval of the N2 revealed that these differences could be related to specific structures that collaborate with the emotional face processing system. In addition to core structures of face recognition, a dipole in the inferior parietal lobule was found in healthy controls as responding to fearful faces, whereas BN patients’ data revealed neural activity in the parahippocampal gyrus. Conclusion: The findings of this study provide novel electrophysiological support for a differential processing of emotional faces in patients with BN as compared to healthy controls. Results suggest that BN patients have deficits in earlier and automatic emotion classification, which are followed by an increased allocation of attentional resources to compensate for those shortcomings. This mechanism might account for bulimics’ comparable ability to classify a variety of emotional expressions on a behavioral level, but also underlines existing findings of increased difficulties in recognizing and evaluating emotions in BN. doi:10.1016/j.clinph.2008.07.157
160. False recognition correlates with b-amyloid (1–42), but not with total Tau in CSF of patients with dementia or mild cognitive impairment—A. Haldenwanger, H. Hildebrandt (Krankenhaus Bremen-Ost, Neurologie, Bremen, Germany) A severe memory impairment forms the core symptom of Alzheimer’s disease (AD) and precedes the clinical presentation of cognitive deterioration for several years. Recent studies show that Alzheimer patients not only suffer from forgetfulness, but also differ in their response bias when recognizing remembered and familiar information. Altered total Tau-protein and b-amyloid (1–42) concentration in the CSF is also a well-known feature of AD, and they predict a conversion to dementia in mild cognitive impaired patients. In this study we correlated recognition scores of neurological patients with memory impairments with total Tau and b-amyloid (1–42). We studied 30 patients, admitted to a neurological hospital, and 21 healthy controls. False recognition scores correlated delayed recall and with b-amyloid (1–42), and B-amyloid (1–42) correlated with delayed recall. Total Tau did not correlate with memory scores and neuropsychological performance in general. We suggest that bamyloid (1–42) may indicate loss of fine-tuning in neuronal response of limbic cortex due to agglomeration of plaques. This process might be more specific for neuropathological alterations in Alzheimer’s disease than processes responsible for the increase of total Tau in CSF, and therefore it shows a stronger correlation with recognition errors. doi:10.1016/j.clinph.2008.07.158
161. A longitudinal study of diffusion tensor imaging after severe traumatic brain injury—M. Kaps 1, A. Okonek 2, S. Schuko 1, V. Glauche 2, C. Weiller 2, J. Liepert 1, R. Lange 2 (1 Kliniken Schmieder, Allensbach, Germany, 2 Neurologische Universitätsklinik, Freiburg, Germany) Introduction: Diffusion Tensor Imaging (DTI) is able to detect damage of subcortical tract systems by measuring changes in fractional anisotropy (FA). Previous studies indicate that the extent of early diffuse axonal injury (DAI) correlates with the severity of the functional neurological deficits following traumatic brain injury. The present study investigates the FA change over time in patients with severe traumatic brain injury, and the correlation with outcome using voxel and ROI-based approaches.
nial magnetic stimulation (er-dpTMS). Subjects were instructed to execute brisk right index finger abduction after a Go-signal. ErdpTMS was delivered during movement preparation at four time points adjusted to the individual reaction time (20%, 50%, 80%, 95% of RT). The test pulse was applied over the left primary motor cortex (M1) and the conditioning pulse either over right M1 (M1-M1) or right premotor cortex (PMC-M1). Results: RTs were comparable in elderly and young subjects (195 ± 20 ms vs. 185 ± 9 ms; p = 0,2). Repeated measures analysis of variance revealed a significant interaction of time by condition (M1-M1, PMC-M1) for both young (p = 0,014; Fig. 1a) and elderly subjects (p = 0,015; Fig. 1b) explained by early interhemispheric facilitation during PMC-M1, whereas M1-M1 showed early inhibition with continuous release of inhibition towards movement onset. The significant interaction of time by group (young, elderly) yielded significance for PMC-M1 (p = 0,013; Fig. 2a), but not for M1-M1 (p = 0,412; Fig. 2b). Young subjects exhibited PMC-M1 facilitation in a very early time frame during movement preparation, whereas the elderly showed early inhibition for PMC-M1 (20% RT) and a delay of interhemispheric facilitation with its maximum after 80% of RT. Discussion: The results are in line with previous EEG, MEG, TMS and combined fMRI–TMS studies showing early ipsilateral involvement of premotor cortex in motor control of the contralateral limb. The new and central finding is that ageing appears to affect interhemispheric interaction in higher-order motor regions, such as the PMC. It is noteworthy that interhemispheric interactions between primary motor areas did not differ between age groups. It can be speculated that in the motor system higher-order regions are more and earlier involved in ageing processes than primary areas as demonstrated in other cognitive domains. doi:10.1016/j.clinph.2008.07.156
159. Emotional face processing in bulimia nervosa: An ERP and source localization study—N. Kühnpast 1, O. Pollatos 2,3, R. Schandry 3 (1 M. Sc. Program Neuro-Cognitive Psychology, LudwigMaximilians-Universität, München, Germany, 2 Neurologische Klinik und Poliklinik, Ludwig-Maximilians-Universität, München, Germany, 3 Department Psycholgie, Ludwig-MaximiliansUniversität, München, Germany) Objective: Empirical evidence suggests substantial deficits regarding emotion recognition in bulimia nervosa (BN). However, the nature of this impairment is the subject of ongoing research. The aim of this study was to investigate the processing of emotional faces in patients with BN. Methods: Event-related potentials (ERPs) were recorded from 22 female patients with BN and 22 matched healthy controls while viewing neutral, happy, fearful, and angry facial expressions, and were further analysed by using the brain electrical source localization method (BESA). Subjects’ facial recognition performance was tested separately in a categorization task. In addition, emotion identification skills were assessed with the Toronto Alexithymia Scale (TAS) and the Eating Disorder Inventory (EDI subscale Interoceptive Awareness). Results: BN patients reported greater difficulty in identifying their own feelings as well as in the regulation of emotional states. Although performance in the categorization task was comparable in BN and controls, the present ERP data demonstrate significant differences at the post-perceptual level of emotional face processing. While early processes of structural encoding, as indexed by the N170, were found to be intact, BN patients had a significant reduction of N2 amplitudes and showed higher P3 amplitudes in response to facial stimuli than healthy subjects. Furthermore, a source analy-
e67
sis in the time interval of the N2 revealed that these differences could be related to specific structures that collaborate with the emotional face processing system. In addition to core structures of face recognition, a dipole in the inferior parietal lobule was found in healthy controls as responding to fearful faces, whereas BN patients’ data revealed neural activity in the parahippocampal gyrus. Conclusion: The findings of this study provide novel electrophysiological support for a differential processing of emotional faces in patients with BN as compared to healthy controls. Results suggest that BN patients have deficits in earlier and automatic emotion classification, which are followed by an increased allocation of attentional resources to compensate for those shortcomings. This mechanism might account for bulimics’ comparable ability to classify a variety of emotional expressions on a behavioral level, but also underlines existing findings of increased difficulties in recognizing and evaluating emotions in BN. doi:10.1016/j.clinph.2008.07.157
160. False recognition correlates with b-amyloid (1–42), but not with total Tau in CSF of patients with dementia or mild cognitive impairment—A. Haldenwanger, H. Hildebrandt (Krankenhaus Bremen-Ost, Neurologie, Bremen, Germany) A severe memory impairment forms the core symptom of Alzheimer’s disease (AD) and precedes the clinical presentation of cognitive deterioration for several years. Recent studies show that Alzheimer patients not only suffer from forgetfulness, but also differ in their response bias when recognizing remembered and familiar information. Altered total Tau-protein and b-amyloid (1–42) concentration in the CSF is also a well-known feature of AD, and they predict a conversion to dementia in mild cognitive impaired patients. In this study we correlated recognition scores of neurological patients with memory impairments with total Tau and b-amyloid (1–42). We studied 30 patients, admitted to a neurological hospital, and 21 healthy controls. False recognition scores correlated delayed recall and with b-amyloid (1–42), and B-amyloid (1–42) correlated with delayed recall. Total Tau did not correlate with memory scores and neuropsychological performance in general. We suggest that bamyloid (1–42) may indicate loss of fine-tuning in neuronal response of limbic cortex due to agglomeration of plaques. This process might be more specific for neuropathological alterations in Alzheimer’s disease than processes responsible for the increase of total Tau in CSF, and therefore it shows a stronger correlation with recognition errors. doi:10.1016/j.clinph.2008.07.158
161. A longitudinal study of diffusion tensor imaging after severe traumatic brain injury—M. Kaps 1, A. Okonek 2, S. Schuko 1, V. Glauche 2, C. Weiller 2, J. Liepert 1, R. Lange 2 (1 Kliniken Schmieder, Allensbach, Germany, 2 Neurologische Universitätsklinik, Freiburg, Germany) Introduction: Diffusion Tensor Imaging (DTI) is able to detect damage of subcortical tract systems by measuring changes in fractional anisotropy (FA). Previous studies indicate that the extent of early diffuse axonal injury (DAI) correlates with the severity of the functional neurological deficits following traumatic brain injury. The present study investigates the FA change over time in patients with severe traumatic brain injury, and the correlation with outcome using voxel and ROI-based approaches.