Neuroimaging of emotional dysregulation in multiple sclerosis: relationship with alexithymia

Patients with multiple sclerosis (MS) often show alexithymia, but the brain mechanisms underlying this emotional disorder remains unknown. We used functional magnetic resonance imaging (fMRI) to investigate alterations of emotion processing and emotion regulation in patients with MS, and their relationships with alexithymia. Nineteen MS patients with minimal disability and twenty healthy control (HC) participants took part in this cross-sectional study. During fMRI, participants viewed scenes conveying negative or positive emotions, and were asked to rate the intensity of their emotional state (1) after spontaneous viewing and (2) after emotion regulation (cognitive reappraisal). Self-reported questionnaires targeting alexithymia and other affective disorders were collected, in addition to functional and anatomical MRI. We compared brain activity and functional connectivity between each group during emotion processing and reappraisal. Moreover, we performed correlation analyses between affective questionnaire scores, subjective emotion ratings, brain activity, and structural integrity. Results showed a higher rate of alexithymia in MS patients. Globally, subjective ratings of emotional state were similar between MS and HC during both spontaneous perception and reappraisal. However, in both task conditions, the MS group showed increased responses to emotional scenes in the orbital inferior frontal gyrus, compared with controls. Moreover, during the reappraisal of negative scenes, these regions displayed increased functional connectivity with the amygdala, whose activity was positively correlated with alexithymia severity in MS. Our findings suggest a direct relationship between alexithymia and a lack of down-regulation of amygdala activity in response to negative emotions during reappraisal in MS. Moreover, they highlight compensatory mechanisms in minimally disabled MS patients, recruiting fronto-striatal circuits, which may serve to preserve homeostasis of amygdala activity and affective state

Disruption of information processing in schizophrenia: The time perspective

AbstractWe review studies suggesting time disorders on both automatic and subjective levels in patients with schizophrenia. Patients have difficulty explicitly discriminating between simultaneous and asynchronous events, and ordering events in time. We discuss the relationship between these difficulties and impairments on a more elementary level. We showed that for undetectable stimulus onset asynchronies below 20ms, neither patients nor controls merge events in time, as previously believed. On the contrary, subjects implicitly distinguish between events even when evaluating them to be simultaneous. Furthermore, controls privilege the last stimulus, whereas patients seem to stay stuck on the first stimulus when asynchronies are sub-threshold. Combining previous results shows this to be true for patients even for asynchronies as short as 8ms. Moreover, this peculiarity predicts difficulties with detecting asynchronies longer than 50ms, suggesting an impact on the conscious ability to time events. Difficulties on the subjective level are also correlated with clinical disorganization. The results are interpreted within the framework of predictive coding which can account for an implicit ability to update events. These results complement a range of other results, by suggesting a difficulty with binding information in time as well as space, and by showing that information processing lacks continuity and stability in patients. The time perspective may help bridge the gap between cognitive impairments and clinical symptoms, by showing how the innermost structure of thought and experience is disrupted

Role of automatic and controlled grouping in the visual organization deficits in patients with schizophrenia,cognitive psychology and functional magnetic resonance imaging studies

Les capacités d'organisation visuo-perceptive sont altérées dans la schizophrénie. Les mécanismes précis de ces altérations demeurent toutefois mal connus. L'objectif de cette thèse est d'identifier l'origine de ces déficits, à l'aide d'outils issus de la psychologie cognitive et de l'IRMf. Une première étude a montré une difficulté spécifique chez les patients pour re-grouper mentalement deux figures appartenant à des groupes perceptifs différents. Leurs capacités à comparer deux figures appartenant à un même groupe perceptif (groupement automatique) étaient par contre préservée. Nous avons formulé l'hypothèse d'un déficit des processus contrôlés, ceux-ci étant nécessaires pour pouvoir re-grouper des informations séparées. Une deuxième étude chez le sujet sain a révélé que le re-groupement mental et le groupement automatique donnaient lieu à des représentations de nature qualitativement différentes. L'objectif de la troisième étude a été de tester si les déficits d'organisation chez les patients pouvaient s'expliquer en termes d'une difficulté fondamentale à re-grouper mentalement des informations séparées, ou à construire une représentation intégrée de l'environnement qui inclut des groupements de nature différente. Les résultats convergent vers cette dernière hypothèse.Visuo-perceptual organization is impaired in schizophrenia. However, the precise mechanisms leading to this deficit are not clear. The present work aimed at understanding the basis of this deficit, with methods issued from cognitive psychology and fMRI. A first study has shown that patients are impaired at mentally comparing two figures which are part of different perceptual groups. However, patients showed preserved abilities to compare two figures belonging to the same perceptual group (automatic grouping). We have proposed that the deficits reflect impaired controlled processes, preventing patients from re-grouping information that is initially segregated. A second study in healthy subjects has shown that mental re-grouping and automatic grouping lead to qualitatively distinct representations. The goal of the third study was to test whether patients deficits would best be described in terms of a basic difficulty to establish links between segregated figures, or in terms of a difficulty to build a coherent representation of the visual environment, integrating qualitatively different groupings. The data favour the latter hypothesis

Role of automatic and controlled grouping in the visual organization deficits in patients with schizophrenia,cognitive psychology and functional magnetic resonance imaging studies

Les capacités d'organisation visuo-perceptive sont altérées dans la schizophrénie. Les mécanismes précis de ces altérations demeurent toutefois mal connus. L'objectif de cette thèse est d'identifier l'origine de ces déficits, à l'aide d'outils issus de laVisuo-perceptual organization is impaired in schizophrenia. However, the precise mechanisms leading to this deficit are not clear. The present work aimed at understanding the basis of this deficit, with methods issued from cognitive psychology and fMRI.

Rôle des processus de groupement automatiques et contrôlés dans les troubles de l organisation visuo-perceptive dans la schizophrénie (Approche en psychologie expérimentale et en imagerie par résonance magnétique fonctionnelle)

Les capacités d organisation visuo-perceptive sont altérées dans la schizophrénie. Les mécanismes précis de ces altérations demeurent toutefois mal connus. L objectif de cette thèse est d identifier l origine de ces déficits, à l aide d outils issus de la psychologie cognitive et de l IRMf. Une première étude a montré une difficulté spécifique chez les patients pour re-grouper mentalement deux figures appartenant à des groupes perceptifs différents. Leurs capacités à comparer deux figures appartenant à un même groupe perceptif (groupement automatique) étaient par contre préservée. Nous avons formulé l hypothèse d un déficit des processus contrôlés, ceux-ci étant nécessaires pour pouvoir re-grouper des informations séparées. Une deuxième étude chez le sujet sain a révélé que le re-groupement mental et le groupement automatique donnaient lieu à des représentations de nature qualitativement différentes. L objectif de la troisième étude a été de tester si les déficits d organisation chez les patients pouvaient s expliquer en termes d une difficulté fondamentale à re-grouper mentalement des informations séparées, ou à construire une représentation intégrée de l environnement qui inclut des groupements de nature différente. Les résultats convergent vers cette dernière hypothèse.Visuo-perceptual organization is impaired in schizophrenia. However, the precise mechanisms leading to this deficit are not clear. The present work aimed at understanding the basis of this deficit, with methods issued from cognitive psychology and fMRI. A first study has shown that patients are impaired at mentally comparing two figures which are part of different perceptual groups. However, patients showed preserved abilities to compare two figures belonging to the same perceptual group (automatic grouping). We have proposed that the deficits reflect impaired controlled processes, preventing patients from re-grouping information that is initially segregated. A second study in healthy subjects has shown that mental re-grouping and automatic grouping lead to qualitatively distinct representations. The goal of the third study was to test whether patients deficits would best be described in terms of a basic difficulty to establish links between segregated figures, or in terms of a difficulty to build a coherent representation of the visual environment, integrating qualitatively different groupings. The data favour the latter hypothesis.STRASBOURG-Sc. et Techniques (674822102) / SudocSudocFranceF

Neuro-Anatomical Correlates of Post-Stroke Positive Perceptual Phenomena

Stroke and other brain lesions produce not only deficits but through the disconnection of various cerebral structures also positive phenomena like hallucinosis or dysmorphopsia. Herein, we studied the neuroanatomical correlate of brain hallucinosis or dysmorphopsia in patients with ischaemic brain lesion

Functional Dissociations Within Posterior Parietal Cortex During Scene Integration and Viewpoint Changes

The posterior parietal cortex (PPC) is an anatomically heterogeneous brain region implicated in a wide range of cognitive operations, including egocentric spatial processing and both short- and long-term memory. Here, we report functional specificities of cytoarchitectonically defined subregions of PPC during the processing of scenes across changes in viewpoint. Participants (n = 16) saw photographs of familiar and unfamiliar places while undergoing functional magnetic resonance imaging (fMRI). On each trial, 4 viewpoints of the same place were presented, with either a plausible sequence of viewpoints (SEQ) or a scrambled order (SCRA). Distinct response profiles were observed within PPC. Area 7A showed increased activity for SEQ versus SCRA order, regardless of place familiarity, whereas the rostral inferior parietal lobule showed preferential increases for unfamiliar versus familiar places in SEQ series. In contrast, more posterior subregions in both superior and inferior PPC exhibited increases for familiar versus unfamiliar places at the end of the sequence, regardless of order. The data highlight the distinctive contribution of several subregions of PPC during the processing of scenes, with specific cortical areas involved in the progressive integration of spatial information across viewpoint changes, and others involved in the retrieval and maintenance of scene information in memory

Functional Dissociations Within Posterior Parietal Cortex During Scene Integration and Viewpoint Changes

The posterior parietal cortex (PPC) is an anatomically heterogeneous brain region implicated in a wide range of cognitive operations, including egocentric spatial processing and both short- and long-term memory. Here, we report functional specificities of cytoarchitectonically defined subregions of PPC during the processing of scenes across changes in viewpoint. Participants (n = 16) saw photographs of familiar and unfamiliar places while undergoing functional magnetic resonance imaging (fMRI). On each trial, 4 viewpoints of the same place were presented, with either a plausible sequence of viewpoints (SEQ) or a scrambled order (SCRA). Distinct response profiles were observed within PPC. Area 7A showed increased activity for SEQ versus SCRA order, regardless of place familiarity, whereas the rostral inferior parietal lobule showed preferential increases for unfamiliar versus familiar places in SEQ series. In contrast, more posterior subregions in both superior and inferior PPC exhibited increases for familiar versus unfamiliar places at the end of the sequence, regardless of order. The data highlight the distinctive contribution of several subregions of PPC during the processing of scenes, with specific cortical areas involved in the progressive integration of spatial information across viewpoint changes, and others involved in the retrieval and maintenance of scene information in memory

On disturbed time continuity in schizophrenia: an elementary impairment in visual perception?

Schizophrenia is associated with a series of visual perception impairments, which might impact on the patients\u27 every day life and be related to clinical symptoms. However, the heterogeneity of the visual disorders make it a challenge to understand both the mechanisms and the consequences of these impairments, i.e., the way patients experience the outer world. Based on earlier psychiatry literature, we argue that issues regarding time might shed a new light on the disorders observed in patients with schizophrenia. We will briefly review the mechanisms involved in the sense of time continuity and clinical evidence that they are impaired in patients with schizophrenia. We will then summarize a recent experimental approach regarding the coding of time-event structure in time, namely the ability to discriminate between simultaneous and asynchronous events. The use of an original method of analysis allowed us to distinguish between explicit and implicit judgments of synchrony. We showed that for SOAs below 20 ms neither patients nor controls fuse events in time. On the contrary subjects distinguish events at an implicit level even when judging them as synchronous. In addition, the implicit responses of patients and controls differ qualitatively. It is as if controls always put more weight on the last occurred event, whereas patients have a difficulty to follow events in time at an implicit level. In patients, there is a clear dissociation between results at short and large asynchronies, that suggest selective mechanisms for the implicit coding of time-event structure. These results might explain the disruption of the sense of time continuity in patients. We argue that this line of research might also help us to better understand the mechanisms of the visual impairments in patients and how they see their environment

On disturbed time continuity in schizophrenia: an elementary impairment in visual perception?

Schizophrenia is associated with a series of visual perception impairments, which might impact on the patients' every day life and be related to clinical symptoms. However, the heterogeneity of the visual disorders make it a challenge to understand both the mechanisms and the consequences of these impairments, i.e., the way patients experience the outer world. Based on earlier psychiatry literature, we argue that issues regarding time might shed a new light on the disorders observed in patients with schizophrenia. We will briefly review the mechanisms involved in the sense of time continuity and clinical evidence that they are impaired in patients with schizophrenia. We will then summarize a recent experimental approach regarding the coding of time-event structure in time, namely the ability to discriminate between simultaneous and asynchronous events. The use of an original method of analysis allowed us to distinguish between explicit and implicit judgments of synchrony. We showed that for SOAs below 20 ms neither patients nor controls fuse events in time. On the contrary subjects distinguish events at an implicit level even when judging them as synchronous. In addition, the implicit responses of patients and controls differ qualitatively. It is as if controls always put more weight on the last occurred event, whereas patients have a difficulty to follow events in time at an implicit level. In patients, there is a clear dissociation between results at short and large asynchronies, that suggest selective mechanisms for the implicit coding of time-event structure. These results might explain the disruption of the sense of time continuity in patients. We argue that this line of research might also help us to better understand the mechanisms of the visual impairments in patients and how they see their environment