Philippe Fossati

French National Centre for Scientific Research, Lutetia Parisorum, Île-de-France, France

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Publications (95)322.3 Total impact

  • Bruno Romeo · Walid Choucha · Philippe Fossati · Jean-Yves Rotge

    No preview · Article · Jan 2016 · The journal of ECT
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    ABSTRACT: Acute depression is associated with impaired self-referential processing. Antidepressant effects on the neural bases of self-referential processing in depression are unknown. This study aimed to assess short- and long-term effects of agomelatine on these neural bases in depressed patients and the association between pre-treatment brain activation and remission of depression 6 months later. We conducted a randomized double-blind, placebo-controlled, functional magnetic resonance imaging (fMRI) study during an emotional self-referential task, including three scanning sessions (baseline, after 1 week, and after 7 weeks). Twenty-five depressed outpatients were included, all treated with agomelatine or placebo for 1 week. Then, all patients received agomelatine for 24 weeks. Fourteen matched healthy volunteers (HV) who received placebo for 1 week were also included. After 7 days, only depressed patients receiving agomelatine significantly deactivated the ventrolateral prefrontal cortex during self-referential processing, as observed in HV at baseline. After 7 weeks, depressed patients significantly increased the activation of the ventral anterior cingulate cortex. Finally dorsomedial prefrontal cortex and precuneus activations at baseline significantly separated remitters from non-remitters at 24 weeks. In depressed patients, agomelatine had short- and long-term effects on brain structures involved in anhedonia and emotional regulation during self-referential processing. Activation of the dorsomedial prefrontal cortex and precuneus could be informative in the development of biomarker-based treatment of major depression.
    No preview · Article · Nov 2015 · Psychiatry Research: Neuroimaging
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    Bruno Romeo · Walid Choucha · Philippe Fossati · Jean-Yves Rotge
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    ABSTRACT: Among treatments currently assessed in major depression, ketamine, has been proposed of great interest, especially because of its very rapid action. However, the time-course of the antidepressive action of ketamine remained unclear. In the present meta-analysis, we provided a clear and objective view regarding the putative antidepressive effect of ketamine and its time-course. We searched the MEDLINE and PsycINFO databases through December 2013, without limits on year of publication, using the key words ketamine and synonyms for mood disorder or episode. Six randomized, double-blind and placebo-controlled trials of ketamine in major depression (n=103 patients) were thus identified. Authors were contacted and they all provided original data necessary for this meta-analysis. Standardized mean differences (SMD) were calculated between the depression scores in ketamine and placebo groups at days 1, 2, 3-4, 7 and 14. Ketamine showed an overall antidepressive efficacy from day 1 to day 7. However, the maintenance of its efficacy over time failed to reach significance in bipolar depression after day 3-4. Significant SMDs were not explained by demographic or clinical characteristics of included samples. The present meta-analysis provides a high level of evidence that ketamine has a rapid antidepressive action during one week, especially in unipolar disorder.
    Full-text · Article · Oct 2015
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    ABSTRACT: The hippocampus is crucial for long-term episodic memory and learning. It undergoes structural change in aging and is sensitive to neurodegenerative and psychiatric diseases. MRS studies have seldom been performed in the hippocampus due to technical challenges. The reproducibility of MRS in the hippocampus has not been evaluated at 3 T. The purpose of the present study was to quantify the concentration of metabolites in a small voxel placed in the hippocampus and evaluate the reproducibility of the quantification. Spectra were measured in a 2.4 mL voxel placed in the left hippocampus covering the body and most of the tail of the structure in 10 healthy subjects across three different sessions and quantified using LCModel. High-quality spectra were obtained, which allowed a reliable quantification of 10 metabolites including glutamate and glutamine. Reproducibility of MRS was evaluated with coefficient of variation, standard errors of measurement, and intraclass correlation coefficients. All of these measures showed improvement with increased number of averages. Changes of less than 5% in concentration of N-acetylaspartate, choline-containing compounds, and total creatine and of less than 10% in concentration of myo-inositol and the sum of glutamate and glutamine can be confidently detected between two measurements in a group of 20 subjects. A reliable and reproducible neurochemical profile of the human hippocampus was obtained using MRS at 3 T in a small hippocampal volume. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.
    Full-text · Article · Aug 2015 · NMR in Biomedicine
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    Jean-Yves Rotge · Cedric Lemogne · Roland Jouvent · Philippe Fossati

    Full-text · Article · Jul 2015 · Journal of psychosomatic research
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    ABSTRACT: Emotions are traditionally considered to be brief states that last for seconds or a few minutes at most. However, due to pioneering theoretical work of Frijda and recent empirical studies, it has become clear that the duration of emotions is actually highly variable with durations ranging from a few seconds to several hours, or even longer. We review research on determinants of emotion duration. Three classes of determinants are identified: features related to the (a) emotion-eliciting event (event duration and event appraisal), (b) emotion itself (nature of the emotion component, nature of the emotion, and emotion intensity), and (c) emotion-experiencing person (dispositions and emotion regulatory actions). Initial evidence on the psychological and neural mechanisms that underlie their effects is discussed.
    No preview · Article · Jul 2015 · Emotion Review
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    Full-text · Article · Mar 2015 · Brain

  • No preview · Article · Dec 2014
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    ABSTRACT: Many functional magnetic resonance imaging studies have explored the neural correlates of social pain that results from social threat, exclusion, rejection, loss or negative evaluation. Although activations have consistently been reported within the anterior cingulate cortex (ACC), it remains unclear which ACC subdivision is particularly involved. To provide a quantitative estimation of the specific involvement of ACC subdivisions in social pain, we conducted a voxel-based meta-analysis. The literature search identified 46 articles that included 940 subjects, the majority of which used the cyberball task. Significant likelihoods of activation were found in both the ventral and dorsal ACC for both social pain elicitation and self-reported distress during social pain. Self-reported distress involved more specifically the subgenual and pregenual ACC than social pain-related contrasts. The cyberball task involved the anterior midcingulate cortex to a lesser extent than other experimental tasks. During social pain, children exhibited subgenual activations to a greater extent than adults. Finally, the ventro-dorsal gradient of ACC activations in cyberball studies was related to the length of exclusion phases. The present meta-analysis contributes to a better understanding of the role of ACC subdivisions in social pain, and it could be of particular importance for guiding future studies of social pain and its neural underpinnings.
    Full-text · Article · Aug 2014 · Social Cognitive and Affective Neuroscience
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    ABSTRACT: Background High-frequency deep brain stimulation (DBS) represents a major stake for treatment for treatment-resistant depression (TRD). We describe a preliminary trial of DBS of two potential brain targets in chronic TRD: the nucleus accumbens (Acb) and, in the event of failure, the caudate nucleus. Experimental procedures Patients were followed for 6 months before surgery (M0). From M1 to M5, they underwent stimulation of the Acb target. PET scans allowed us to track metabolic modifications resulting from this stimulation. The caudate target of nonresponders was stimulated between M5 and M9. Patients then entered an extension phase, in which it was possible to adapt stimulation parameters and treatments. Results Six patients were included and four were operated on. At M5, none of the patients were either responders or remitters, but we did observe a decrease in Hamilton Depression Rating Scale (HDRS) scores. Three patients were switched to caudate stimulation, but no improvement was observed. During the extension phase, the Acb target was stimulated for all patients, three of whom exhibited a significant response. A decrease in glucose metabolism was observed after Acb stimulation, in the posterior cingulate gyrus, left frontal lobe, superior and medial gyrus, and bilateral cerebellum. An increase in metabolism was observed in the bilateral frontal lobe (superior gyrus), left frontal lobe (medial gyrus), and right limbic lobe (anterior cingulate gyrus). Conclusion The results of this trial suggest that the Acb is a more promising target than the caudate. NCT01569711
    Full-text · Article · Aug 2014 · European Neuropsychopharmacology
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    Jean-Yves Rotgé · Philippe Fossati · Cedric Lemogne

    Full-text · Article · Apr 2014 · The Journal of Clinical Psychiatry
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    Marco Sperduti · Sophie Guionnet · Philippe Fossati · Jacqueline Nadel
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    ABSTRACT: Two sets of brain areas are repeatedly reported in neuroimaging studies on social cognition: the Mirror Neuron System and the Mentalizing System. The Mirror System is involved in goal understanding and has been associated with several emotional and cognitive functions central to social interaction, ranging from empathy to gestural communication and imitation. The Mentalizing System is recruited in tasks requiring cognitive processes such as self-reference and understanding of other's intentions. Although theoretical accounts for an interaction between the two systems have been proposed, little is known about their synergy during social exchanges. In order to explore this question, we have recorded brain activity by means of functional MRI during live social exchanges based on reciprocal imitation of hand gestures. Here, we investigate, using the method of psychophysiological interaction, the changes in functional connectivity of the Mirror System due to the conditions of interest (being imitated, imitating) compared with passive observation of hand gestures. We report a strong coupling between the Mirror System and the Mentalizing System during the imitative exchanges. Our findings suggest a complementary role of the two networks during social encounters. The Mirror System would engage in the preparation of own actions and the simulation of other's actions, while the Mentalizing System would engage in the anticipation of the other's intention and thus would participate to the co-regulation of reciprocal actions. Beyond a specific effect of imitation, the design used offers the opportunity to tackle the role of role-switching in an interpersonal account of social cognition.
    Full-text · Article · Jan 2014 · Cognitive Processing

  • No preview · Article · Dec 2013
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    ABSTRACT: There are two distinct modes of self-focus: analytical self-focus is abstract, general and evaluative whereas experiential self-focus is concrete, specific and non-evaluative. Using functional magnetic resonance imaging (fMRI), we investigated the neural bases of these two modes of self-focus in relation with brooding, the maladaptive form of rumination. Forty-one French-speaking right-handed healthy young adults (10 men, mean age ± s.d.: 21.8 ± 2.3 years) engaged in analytical and experiential self-focus triggered by verbal stimuli during fMRI. Brooding was measured with the 22-item Rumination Response Style scale. Individuals with lower brooding scores showed greater activation of the posterior cingulate cortex/precuneus during analytical than experiential self-focus, whereas individuals with higher brooding scores did not. This is consistent with the hypothesis that brooding is associated with less control over the nature of the self-focus engaged. These findings may help to refine our understanding of how rumination promotes depression through maladaptive self-focus.
    Full-text · Article · Dec 2013 · Social Cognitive and Affective Neuroscience
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    Philippe Fossati
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    ABSTRACT: Autobiographical memory (AM) defines the memory systems that encode, consolidate, and retrieve personal events and facts, AM is strongly related to self-perception and self representation. We review here the neural correlates of AM retrieval. AM retrieval encompasses a large neural network including the prefrontal, temporal, and parietal cortex, and limbic structures. All these regions subserve the cognitive processes (episodic remembering, cognitive control, self-processing, and scene construction) at play during memory retrieval. We emphasize the specific role of medial prefrontal cortex and precuneus in self-processing during autobiographical memory retrieval. Overall, these data call for further studies in psychiatric patients, to investigate the neural underpinnings of autobiographical memory and self-representation in mental disorders.
    Preview · Article · Dec 2013
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    Ayna Baladi Nejad · Philippe Fossati · Cédric Lemogne
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    ABSTRACT: Major depression is associated with a bias toward negative emotional processing and increased self-focus, i.e., the process by which one engages in self-referential processing. The increased self-focus in depression is suggested to be of a persistent, repetitive and self-critical nature, and is conceptualized as ruminative brooding. The role of the medial prefrontal cortex in self-referential processing has been previously emphasized in acute major depression. There is increasing evidence that self-referential processing as well as the cortical midline structures play a major role in the development, course, and treatment response of major depressive disorder. However, the links between self-referential processing, rumination, and the cortical midline structures in depression are still poorly understood. Here, we reviewed brain imaging studies in depressed patients and healthy subjects that have examined these links. Self-referential processing in major depression seems associated with abnormally increased activity of the anterior cortical midline structures. Abnormal interactions between the lateralized task-positive network, and the midline cortical structures of the default mode network, as well as the emotional response network, may underlie the pervasiveness of ruminative brooding. Furthermore, targeting this maladaptive form of rumination and its underlying neural correlates may be key for effective treatment.
    Full-text · Article · Oct 2013 · Frontiers in Human Neuroscience
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    ABSTRACT: Many choice situations require imagining potential outcomes, a capacity that was shown to involve memory brain regions such as the hippocampus. We reasoned that the quality of hippocampus-mediated simulation might therefore condition the subjective value assigned to imagined outcomes. We developed a novel paradigm to assess the impact of hippocampus structure and function on the propensity to favor imagined outcomes in the context of intertemporal choices. The ecological condition opposed immediate options presented as pictures (hence directly observable) to delayed options presented as texts (hence requiring mental stimulation). To avoid confounding simulation process with delay discounting, we compared this ecological condition to control conditions using the same temporal labels while keeping constant the presentation mode. Behavioral data showed that participants who imagined future options with greater details rated them as more likeable. Functional MRI data confirmed that hippocampus activity could account for subjects assigning higher values to simulated options. Structural MRI data suggested that grey matter density was a significant predictor of hippocampus activation, and therefore of the propensity to favor simulated options. Conversely, patients with hippocampus atrophy due to Alzheimer's disease, but not patients with Fronto-Temporal Dementia, were less inclined to favor options that required mental simulation. We conclude that hippocampus-mediated simulation plays a critical role in providing the motivation to pursue goals that are not present to our senses.
    No preview · Article · Oct 2013 · PLoS Biology

  • No preview · Article · Oct 2013 · European Neuropsychopharmacology
  • Cédric Lemogne · Frédéric Limosin · Philippe Fossati
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    ABSTRACT: Young, Erickson, and Drevets (2012) reported that positive and neutral cue words elicited less positive memories among patients with major depression than among healthy controls, while memories from patients were less specific than those from controls, regardless of their intrinsic valence. These results suggested methodological refinements that may shed light on several aspects of autobiographical memory impairment in mental disorders.
    No preview · Article · Aug 2013 · Psychological Reports
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    ABSTRACT: Visual perspective (i.e. first-person versus third-person perspective) during autobiographical memory (AM) retrieval plays a role in both emotional regulation and self-related processes. However, its neural underpinnings remain mostly unexplored. Visual perspective during AM retrieval was assessed in two independent datasets of 45 and 20 healthy young adults with two different AM retrieval tasks. Diffeomorphic anatomical registration using exponentiated lie algebra and voxel-based morphometry were used to assess individual differences in the precuneus grey matter volume. The spontaneous tendency to recall memories from a first-person perspective was positively correlated with the right precuneus volume among the two independent datasets. Whole-brain analyses revealed that these results were relatively specific to the anterior part of the right precuneus. Our results provide first evidence for the role of the precuneus in egocentric spatial processing in the context of AM retrieval among healthy subjects.
    Full-text · Article · Apr 2013 · Brain Structure and Function

Publication Stats

4k Citations
322.30 Total Impact Points

Institutions

  • 2003-2015
    • French National Centre for Scientific Research
      Lutetia Parisorum, Île-de-France, France
  • 2009-2014
    • Pierre and Marie Curie University - Paris 6
      • Centre Émotion
      Lutetia Parisorum, Île-de-France, France
    • Assistance Publique – Hôpitaux de Paris
      Lutetia Parisorum, Île-de-France, France
  • 1995-2014
    • Hôpital La Pitié Salpêtrière (Groupe Hospitalier "La Pitié Salpêtrière - Charles Foix")
      Lutetia Parisorum, Île-de-France, France
  • 2013
    • Polytech Paris-UPMC
      Lutetia Parisorum, Île-de-France, France
  • 2012
    • Emory University
      Atlanta, Georgia, United States
  • 2007
    • Hôpitaux Universitaires La Pitié salpêtrière - Charles Foix
      Lutetia Parisorum, Île-de-France, France
  • 2002-2004
    • Baycrest
      Toronto, Ontario, Canada
    • French Institute of Health and Medical Research
      Lutetia Parisorum, Île-de-France, France