Pierre Vidailhet

Publications of Pierre Vidailhet

• Self-images and related autobiographical memories in schizophrenia.

  Authors: Mehdi Bennouna-Greene, Fabrice Berna, Martin A Conway, Clare J Rathbone, Pierre Vidailhet, Jean-Marie Danion

  Consciousness and cognition. 03/2012; 21(1):247-57.

  Schizophrenia is a severe mental illness, which affects sense of identity. While the ability to have a coherent vision of the self (i.e., self-images) relies partly on its reciprocal relationshipsSchizophrenia is a severe mental illness, which affects sense of identity. While the ability to have a coherent vision of the self (i.e., self-images) relies partly on its reciprocal relationships with autobiographical memories, little is known about how memories ground "self-images" in schizophrenia. Twenty-five patients with schizophrenia and 25 controls were asked to give six autobiographical memories related to four self-statements they considered essential for defining their identity. Results showed that patients' self-images were more passive than those of controls. Autobiographical memories underlying self-images were less thematically linked to these self-images in patients. We also found evidence of a weakened sense of self and a deficient organization of autobiographical memories grounding the self in schizophrenia. These abnormalities may account for the poor cohesiveness of the self in schizophrenia.

• fMRI working memory hypo-activations in schizophrenia come with a coupling deficit between arousal and cognition.

  Authors: Jack R Foucher, David Luck, Corinne Marrer, Bich-Thuy Pham, Daniel Gounot, Pierre Vidailhet, Helene Otzenberger

  Psychiatry research. 08/2011; 194(1):21-9.

  Cognition has become a target for therapeutic intervention and favoring arousal could be a way to help patients. Working memory is an arousal dependent cognitive function. This study used functionalCognition has become a target for therapeutic intervention and favoring arousal could be a way to help patients. Working memory is an arousal dependent cognitive function. This study used functional MRI (fMRI) as a surrogate marker of working memory to evaluate the sensitivity of patients' hypoactive regions to arousal in a subpopulation of rehabilitated patients. Are hypoactive regions sensitive to arousal? Does the deficit result from arousal deficit or improper coupling with cognitive activity? Eighteen patients and matched controls were recruited. Participants performed a working memory task during combined electroencephalographic (EEG) and fMRI measurements. Cortical regions sensitive to arousal were defined as those which were inversely correlated with low EEG frequencies. Overlap between the arousal-sensitive and hypoactive regions was assessed by mutual information. Arousal-cognitive coupling was evaluated by the correlation between the arousal effect and the task effect. In the patient group, most hypoactive voxels were sensitive to arousal and corresponded to the prefronto-parietal network. But patients had no arousal deficit. Although arousal seems to improve cognitive activity in most of the patients' cortical areas, this coupling appears to be specifically disturbed in their hypoactive regions. In conclusion, although increasing arousal may help cognition, it may do so in an unspecific way.

• Atypical behavioural effects of lorazepam: clues to the design of novel therapies?

  Authors: Anne Giersch, Muriel Boucart, Mark Elliott, Pierre Vidailhet

  Pharmacology & therapeutics. 02/2010; 126(1):94-108.

  Aside from their pharmacokinetic properties, e.g. their speed of action and the duration of residual effects, benzodiazepines are still considered as equivalent in terms of their effects onAside from their pharmacokinetic properties, e.g. their speed of action and the duration of residual effects, benzodiazepines are still considered as equivalent in terms of their effects on cognition. Here we review evidence suggesting that certain benzodiazepines, especially lorazepam, differ in a number of respects, in particular with respect to their effects on cognition. We focus this review on memory, attention and visual perception, where impairments may be brought about by only a subset of benzodiazepines in spite of their administration at doses inducing similar sedative effects. This precludes an explanation in terms of sedation. Differences in the effects of benzodiazepines have also been found in electrophysiological and animal behavioural studies. These studies are important for therapeutic approaches for two reasons: first, effects of benzodiazepine prescription on cognitive functions will differ according to the benzodiazepine, contrary to what is usually believed. Less straightforwardly are the possible therapeutic implications of specific effects on cognition following treatment with lorazepam. Indeed, the specific effects this drug has on cognition may reveal not only side-effects but also effects of potential therapeutic value. Current research concentrates on a fine scale analysis of the effects of GABA on different sub-types of GABA(A) receptors. We suggest that from looking at what makes lorazepam different in a behavioural sense from other benzodiazepines we may be in a position to design innovative treatments for major aspects of complex disorders, including schizophrenia.

• Functional mechanisms of episodic memory impairment in schizophrenia.

  Authors: Jean-Marie Danion, Caroline Huron, Pierre Vidailhet, Fabrice Berna

  Canadian journal of psychiatry. Revue canadienne de psychiatrie. 12/2007; 52(11):693-701.

  OBJECTIVE: To achieve a better understanding of the functional mechanisms underlying episodic memory dysfunction in schizophrenia, which is a prerequisite for unravelling schizophrenia's neuralOBJECTIVE: To achieve a better understanding of the functional mechanisms underlying episodic memory dysfunction in schizophrenia, which is a prerequisite for unravelling schizophrenia's neural correlates in neuroimaging studies and, more generally, for developing an integrated approach to the pathophysiology of schizophrenia. It is also crucial for developing cognitive remediation. METHOD: This paper reviews empirical evidence of episodic memory dysfunction in schizophrenia obtained with reference to various theoretical models of episodic memory. RESULTS: All the studies converge to show a significant impairment of the critical feature of episodic memory: conscious recollection. Schizophrenia is also associated with a defect of autobiographical memory. The episodic memory dysfunction results from a predominant failure of strategic processing at encoding, although an impairment of strategic processing at retrieval cannot be ruled out. The possibility that it is not the execution of the encoding strategies that is defective but, rather, their self-initiation by the patients is plausible. CONCLUSIONS: These findings may explain some behavioural abnormalities associated with schizophrenia, notably, inadequate functional outcomes in everyday life. They may also have implications for cognitive remediation and better social and work functioning of patients with schizophrenia.

• Dissociation between perceptual processing and priming in long-term lorazepam users.

  Authors: Anne Giersch, Pierre Vidailhet

  The international journal of neuropsychopharmacology / official scientific journal of the Collegium Internationale Neuropsychopharmacologicum (CINP). 01/2007; 9(6):695-704.

  Acute effects of lorazepam on visual information processing, perceptual priming and explicit memory are well established. However, visual processing and perceptual priming have rarely been exploredAcute effects of lorazepam on visual information processing, perceptual priming and explicit memory are well established. However, visual processing and perceptual priming have rarely been explored in long-term lorazepam users. By exploring these functions it was possible to test the hypothesis that difficulty in processing visual information may lead to deficiencies in perceptual priming. Using a simple blind procedure, we tested explicit memory, perceptual priming and visual perception in 15 long-term lorazepam users and 15 control subjects individually matched according to sex, age and education level. Explicit memory, perceptual priming, and the identification of fragmented pictures were found to be preserved in long-term lorazepam users, contrary to what is usually observed after an acute drug intake. The processing of visual contour, on the other hand, was still significantly impaired. These results suggest that the effects observed on low-level visual perception are independent of the acute deleterious effects of lorazepam on perceptual priming. A comparison of perceptual priming in subjects with low- vs. high-level identification of new fragmented pictures further suggests that the ability to identify fragmented pictures has no influence on priming. Despite the fact that they were treated with relatively low doses and far from peak plasma concentration, it is noteworthy that in long-term users memory was preserved.

• Evidence for impaired mnemonic strategy use among patients with schizophrenia using the part-list cuing paradigm.

  Authors: Bruce K Christensen, Todd A Girard, Aaron S Benjamin, Pierre Vidailhet

  Schizophrenia research. 08/2006; 85(1-3):1-11.

  PURPOSE: Strategic and mnemonic abilities of person with schizophrenia (SCZ) were studied using a part-list cuing (PLC) task. In this task, presentation of retrieval cues in the form of a subset ofPURPOSE: Strategic and mnemonic abilities of person with schizophrenia (SCZ) were studied using a part-list cuing (PLC) task. In this task, presentation of retrieval cues in the form of a subset of studied words typically impairs recall of the remaining items. This impairment is thought to reflect a disruption of participants' natural retrieval strategies. METHODS: Participants with SCZ and healthy controls (ns = 28) studied word lists with three different levels of semantic organization: (a) unrelated, (b) categorized, but presented in a random order, and (c) presented by category. For each type of list, participants recalled words under both free-recall and PLC conditions. RESULTS: Consistent with SCZ-related impairment of strategic retrieval processes, the SCZ group was less disrupted by PLC interference than controls in the unrelated-list condition. Comparison of free recall across lists also indicated a consistent deficit in SCZ despite varying levels of difficulty and retrieval contexts. Nonetheless, the SCZ group demonstrated parallel improvement to the healthy group with increasing list organization. CONCLUSIONS: These results provide evidence of deficient retrieval processes in SCZ in a context placing maximal requirements for utilization of self-initiated, effortful, mnemonic strategies. Unlike most extant results demonstrating mnemonic impairment in persons with SCZ, the present results cannot be accounted for by task difficulty; SCZ participants' recall was less disrupted by PLC than was that of healthy participants. Results also demonstrated that SCZ participants could benefit, in terms of recall and strategy use, from list organization when this structure was explicitly provided at test.

• Atypical behavioural effects of lorazepam: Clues to the design of novel therapies?

  Authors: Anne Giersch, Muriel Boucart, Mark Elliott, Pierre Vidailhet

  Pharmacology & Therapeutics.

  Aside from their pharmacokinetic properties, e.g. their speed of action and the duration of residual effects, benzodiazepines are still considered as equivalent in terms of their effects onAside from their pharmacokinetic properties, e.g. their speed of action and the duration of residual effects, benzodiazepines are still considered as equivalent in terms of their effects on cognition. Here we review evidence suggesting that certain benzodiazepines, especially lorazepam, differ in a number of respects, in particular with respect to their effects on cognition. We focus this review on memory, attention and visual perception, where impairments may be brought about by only a subset of benzodiazepines in spite of their administration at doses inducing similar sedative effects. This precludes an explanation in terms of sedation. Differences in the effects of benzodiazepines have also been found in electrophysiological and animal behavioural studies.These studies are important for therapeutic approaches for two reasons: first, effects of benzodiazepine prescription on cognitive functions will differ according to the benzodiazepine, contrary to what is usually believed. Less straightforwardly are the possible therapeutic implications of specific effects on cognition following treatment with lorazepam. Indeed, the specific effects this drug has on cognition may reveal not only side-effects but also effects of potential therapeutic value. Current research concentrates on a fine scale analysis of the effects of GABA on different sub-types of GABAA receptors. We suggest that from looking at what makes lorazepam different in a behavioural sense from other benzodiazepines we may be in a position to design innovative treatments for major aspects of complex disorders, including schizophrenia.