Nicolas Franck

Modulating the experience of agency: a positron emission tomography study.

This study investigated agency, the feeling of being causally involved in an action. This is the feeling that leads us to attribute an action to ourselves rather than to another person. We were interested in the effects of experimentally modulating this experience on brain areas known to be involved in action recognition and self-recognition. We used a device that allowed us to modify the subjects degree of control of the movements of a virtual hand presented on a screen. Four main conditions were used: (1) a condition where the subject had a full control of the movements of the virtual hand, (2) a condition where the movements of the virtual hand appeared rotated by 25 degrees with respect to the movements made by the subject, (3) a condition where the movements of the virtual hand appeared rotated by 50 degrees, and (4) a condition where the movements of the virtual hand were produced by another person and did not correspond to the subjects movements. The activity of two main brain areas appeared to be modulated by the degree of discrepancy between the movement executed and the movement seen on the screen. In the inferior part of the parietal lobe, specifically on the right side, the less the subject felt in control of the movements of the virtual hand, the higher the level of activation. A reverse covariation was observed in the insula. These results demonstrate that the level of activity of specific brain areas maps onto the experience of causing or controlling an action. The implication of these results for understanding pathological conditions is discussed.

Neural correlates of action attribution in schizophrenia

Patients with first-rank symptoms (FRS) of schizophrenia do not experience all of their actions and personal states as their own. FRS may be associated with an impaired ability to correctly attribute an action to its origin. In the present study, we examined regional cerebral blood flow (rCBF) with positron emission tomography during an action-attribution task in a group of patients with FRS. We used a device previously used with healthy subjects that allows the experimenter to modulate the subjects degree of movement control (and thus action attribution) of a virtual hand presented on a screen. In healthy subjects, the activity of the right angular gyrus and the insula cortex appeared to be modulated by the subjects degree of movement control of the virtual hand. In the present study, the schizophrenic patients did not show this pattern. We found an aberrant relationship between the subjects degree of control of the movements and rCBF in the right angular gyrus and no modulation in the insular cortex. The implications of these results for understanding pathological conditions such as schizophrenia are discussed.

Cognitive remediation: a promising tool for the treatment of schizophrenia

Cognitive remediation is a type of treatment added recently to the range of tools available to therapists. It includes a number of miscellaneous methods that aim to correct some of the cognitive impairments observed in schizophrenia. These cover the fields of target attention, memory and executive deficits, as well as impaired social cognition. Cognitive remediation acts as a complement to medication and psychological therapies, which constitute the core methods of treatment for schizophrenia. The present paper reviews the state of the art in cognitive remediation. The principle underlying this innovative therapeutic approach is the enhancement of the cognitive resources of patients with schizophrenia in order to improve their cognitive functions, social skills and in some cases alleviate some of the symptoms of the disease. Several programs developed within the past two decades (e.g., IPT, CRT, NEAR, CET, NET, CRT and CAT) are becoming more widely used. Their efficacy on neurocognition and on functional outcome has been demonstrated, with inconstant continuation of benefit after completion of treatment. The sustainability of the cognitive and functional improvements following completion of these programs has to be further studied. Other programs aimed at acting upon altered social cognition (one of the critical facets of schizophrenia) are still in the experimental stages, but the results obtained so far are encouraging. A preliminary study has also demonstrated the effectiveness of board games in improving cognitive functioning, which seems to be a highly promising therapeutic avenue owing to its ease of use.

Perception of self-generated action in schizophrenia

Introduction. Self-generated actions involve central processes of sensorimotor integration that continuously monitor sensory inputs to ensure that motor outputs are congruent with our intentions. This mechanism works automatically in normal conditions but becomes conscious whenever a mismatch happens during the execution of action between expected and current sensorimotor reafferences. It is now admitted in the literature that sensorimotor processes as well as the ability to predict the consequences of our own actions imply the existence of a forward model of action, which is based on efference copies. Recently, it has been proposed that positive symptoms expressed by schizophrenic patients, such as delusions of control or thought insertions, arise because of a deficiency in this forward model, and more particularly, because of a lack of awareness of certain aspects of motor control derived from such an internal model. Method. To test further this hypothesis, 19 schizophrenic patients (10 with and 9 without Schneiderian symptoms) and 19 control subjects performed a visuo-motor conflict task and had verbally to report the felt position of their hand at the end of each trial. Results. Under this experimental procedure, schizophrenic patients - whatever their clinical phenotype - failed to switch to a conscious representation of their hand movements, and then consequently to maintain their level of performance for the sensorimotor adjustment in comparison with controls. Conclusion. Our findings suggest two facts. First, that a functional monitoring of action, based on a forward

Self-Monitoring in Schizophrenia

Many patients suffering from schizophrenia feel dispossessed from some of their actions or thoughts. This dis- possession could result from impaired self-monitoring (SM), defined as the ability to monitor self-willed intentions and actions. SM has been widely studied during the past decades with very different paradigms; central error correction, feed- back distortion, sense of effort, and motor imagery. The present article first reviews the methods used and results obtained in investigation of SM. Second, we address what we consider to be the critical questions that must be answered in order to fully understand the role of SM deficit in schizophrenia: 1) Is SM deficit only impaired in patients with specific symp- toms? 2) Is SM deficit associated with other cognitive processes that are also impaired in patients with schizophrenia? 3) Can SM impairment be characterized as a trait or a state marker? Finally, we discuss the consequences of SM investiga- tion on diagnostic evaluation and therapeutic orientations and we propose future research that we think is essential in or- der to clarify the role of SM in schizophrenia.

Augmentation of induced visual gamma activity by increased task complexity

Recently the study of induced gamma band oscillations has focused on their modulation by top‐down processes, mainly attention. Numerous studies have observed an increase in induced gamma band energy with increases in covert selective attention and visual perception. The current study investigated the modulation of visually induced gamma band oscillations by top‐down processes associated with task complexity. Fourteen human subjects performed a reaction time task under two experimental conditions that differed in task complexity. In one, subjects simply had to press one of four buttons that corresponded to a colour stimulus shown to the subject. In the second, the stimulus response mapping was altered by the implementation of a rule, thus increasing task complexity. Cortical electrical activity was recorded using a 65 electrode whole scalp electroencephalographic (EEG) net. The EEG activity was analysed using Morlet wavelets to produce time–frequency maps. Although induced gamma band activity was observed in both conditions, there was significantly greater energy during the rule‐operation condition at approximately 276 ms after the appearance of the stimulus. This increase was localized to electrodes overlying the right‐central parietal scalp. The results of this study show that top‐down processes modulate the level of induced gamma band activity. We discuss these findings in terms of the role of gamma oscillations in the construction of a sensory representation useful for a correct motor response.

Delusions and metacognition in patients with schizophrenia.

Introduction. The aim of the present study was to explore the basis of the strong feeling of conviction and the high resistance to change characteristic of delusions and to test whether patients with schizophrenia suffering from delusions have specific metacognitive impairments when compared to both patients without delusions and healthy controls. Methods. 14 actively delusional patients with schizophrenia, 14 nondelusional patients, and 14 healthy subjects were administered two measures assessing different aspects of metacognition: an emotional metacognitive version of the WCST adapted from Koren et al. (2004) and the Beck Cognitive Insight Scale. Results. Relative to both healthy controls and nondelusional patients, delusional participants were specifically impaired on metacognitive measures of free choice improvement and global monitoring. This was correlated with high self-certainty on the BCIS relative to nondelusional patients. Conclusions. Our results suggest that metacognitive impairments play an important role in the maintenance of delusional beliefs. It may therefore be important to adapt remediation strategies to the metacognitive profiles of patients.

Left temporoparietal transcranial magnetic stimulation in treatment-resistant schizophrenia with verbal hallucinations

Left temporoparietal repetitive transcranial magnetic stimulation (rTMS) reportedly diminishes verbal hallucinations. A 21-year-old schizophrenic man, who had killed his mother in the belief that she was a demon, failed to respond to combined treatment with a variety of antipsychotic agents. His persistent hallucinations consisted of two voices (God and the Devil). As an adjunct to continued antipsychotic medication, the patient received a course of rTMS: 10 sessions of 1-Hz stimulations near Wernickes area. After rTMS, the patients hallucinations grew less intrusive and he no longer required isolation. Although the improvement could be a delayed effect of medication, further trials of rTMS in cases of this type appear justified.

The Odor Context Facilitates the Perception of Low-Intensity Facial Expressions of Emotion

It has been established that the recognition of facial expressions integrates contextual information. In this study, we aimed to clarify the influence of contextual odors. The participants were asked to match a target face varying in expression intensity with non-ambiguous expressive faces. Intensity variations in the target faces were designed by morphing expressive faces with neutral faces. In addition, the influence of verbal information was assessed by providing half the participants with the emotion names. Odor cues were manipulated by placing participants in a pleasant (strawberry), aversive (butyric acid), or no-odor control context. The results showed two main effects of the odor context. First, the minimum amount of visual information required to perceive an expression was lowered when the odor context was emotionally congruent: happiness was correctly perceived at lower intensities in the faces displayed in the pleasant odor context, and the same phenomenon occurred for disgust and anger in the aversive odor context. Second, the odor context influenced the false perception of expressions that were not used in target faces, with distinct patterns according to the presence of emotion names. When emotion names were provided, the aversive odor context decreased intrusions for disgust ambiguous faces but increased them for anger. When the emotion names were not provided, this effect did not occur and the pleasant odor context elicited an overall increase in intrusions for negative expressions. We conclude that olfaction plays a role in the way facial expressions are perceived in interaction with other contextual influences such as verbal information.

Mesure du déficit de reconnaissance des émotions faciales dans la schizophrénie. Étude préliminaire du test de reconnaissance des émotions faciales (TREF)

INTRODUCTION The impairment of social cognition, including facial affects recognition, is a well-established trait in schizophrenia, and specific cognitive remediation programs focusing on facial affects recognition have been developed by different teams worldwide. However, even though social cognitive impairments have been confirmed, previous studies have also shown heterogeneity of the results between different subjects. Therefore, assessment of personal abilities should be measured individually before proposing such programs. PURPOSE Most research teams apply tasks based on facial affects recognition by Ekman et al. or Gur et al. However, these tasks are not easily applicable in a clinical exercise. Here, we present the Facial Emotions Recognition Test (TREF), which is designed to identify facial affects recognition impairments in a clinical practice. The test is composed of 54 photos and evaluates abilities in the recognition of six universal emotions (joy, anger, sadness, fear, disgust and contempt). Each of these emotions is represented with colored photos of 4 different models (two men and two women) at nine intensity levels from 20 to 100%. Each photo is presented during 10 seconds; no time limit for responding is applied. METHOD The present study compared the scores of the TREF test in a sample of healthy controls (64 subjects) and people with stabilized schizophrenia (45 subjects) according to the DSM IV-TR criteria. We analysed global scores for all emotions, as well as sub scores for each emotion between these two groups, taking into account gender differences. Our results were coherent with previous findings. Applying TREF, we confirmed an impairment in facial affects recognition in schizophrenia by showing significant differences between the two groups in their global results (76.45% for healthy controls versus 61.28% for people with schizophrenia), as well as in sub scores for each emotion except for joy. Scores for women were significantly higher than for men in the population without psychiatric diagnosis. The study also allowed the identification of cut-off scores; results below 2 standard deviations of the healthy control average (61.57%) pointed to a facial affect recognition deficit. CONCLUSION The TREF appears to be a useful tool to identify facial affects recognition impairment in schizophrenia. Neuropsychologists, who have tried this task, have positive feedback. The TREF is easy to use (duration of about 15 minutes), easy to apply in subjects with attentional difficulties, and tests facial affects recognition at ecological intensity levels. These results have to be confirmed in the future with larger sample sizes, and in comparison with other tasks, evaluating the facial affects recognition processes.