Publications by authors named "Marc Barakat"

Background: Data on Emotion Dysregulation among youth in Lebanon is scarce. Given that Emotion Dysregulation is associated with psychopathology and has a negative impact on youth outcomes, there is a need to better understand the prevalence, clinical and demographic correlates of Emotion Dysregulation.

Methods: This study is a secondary analysis of the Psychopathology in Children and Adolescents in Lebanon Study which recruited 1517 youth and one parent from a nationally representative sample.

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Background: Psychopathy has been described as "the first personality disorder to be recognized in psychiatry". It has three core features: affective, interpersonal, and behavioral. The Levenson Self-Report Psychopathy (LSRP) scale is used to screen for and measure psychopathy.

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Background: Continuous Performance Tests, like the Test of Variables of Attention (TOVA), are commonly used to assess attention processes in clinical settings. Although a few previous studies have explored the effects of emotions on the outcome of such tests, the results are scarce and contradictory at times.

Objective: Through this retrospective study, we  aimed to explore the correlation between performance on the TOVA and parent-reported emotional symptoms in youth.

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Article Synopsis
  • Psychiatric disorders significantly impact children and adolescents globally, and Lebanon's first national study aimed to assess the prevalence of these disorders amidst its ongoing challenges.
  • The study involved a stratified sample of 1517 individuals aged 5 to 17, using various self-reported questionnaires to identify potential psychiatric disorders.
  • Results showed that about 32.7% screened positive for at least one disorder, with only 5% seeking professional help; factors like academic struggles, chronic illnesses, high parental stress, and bullying increased the likelihood of screening positive, while higher family income was linked to a lower risk.
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Some researchers believe that Sluggish Cognitive Tempo (SCT) should be its own psychiatric disorder. However, despite the abundance of literature describing its possible symptoms, evidence of its clinical impact on cognitive tests and some clinical comorbidities is still weak. This retrospective study aimed to analyze the added clinical value of exploring SCT symptoms prior to a neuropsychological assessment in a youth population diagnosed with an Attention-Deficit/Hyperactivity Disorder (ADHD).

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Article Synopsis
  • The study investigates how sleep improves motor sequence learning by examining changes in brain connectivity, particularly in the striatum.
  • During the experiment, researchers found that the cortico-striatal network showed increased functional integration after sleep compared to just being awake during the day.
  • These results suggest that sleep enhances communication between brain regions involved in motor learning, highlighting its importance in skill consolidation.
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The human electroencephalogram (EEG) during non-rapid eye movement sleep (NREM) is characterized mainly by high-amplitude (>75 μV), slow-frequency (<4 Hz) waves (slow waves), and sleep spindles (∼11-15 Hz; >0.25 s). These NREM oscillations play a crucial role in brain plasticity, and importantly, NREM sleep oscillations change considerably with aging.

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Aging induces multiple changes to sleep spindles, which may hinder their alleged functional role in memory and sleep protection mechanisms. Brain aging in specific cortical regions could affect the neural networks underlying spindle generation, yet the topography of these age-related changes is currently unknown. In the present study, we analyzed spindle characteristics in 114 healthy volunteers aged between 20 and 73 years over 5 anteroposterior electroencephalography scalp derivations.

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The purpose of this study was to investigate the predictive function of sleep spindles in motor sequence consolidation. BOLD responses were acquired in 10 young healthy subjects who were trained on an explicitly known 5-item sequence using their left nondominant hand, scanned at 9:00 pm while performing that same task and then were retested and scanned 12 h later after a night of sleep during which polysomnographic measures were recorded. An automatic algorithm was used to detect sleep spindles and to quantify their characteristics (i.

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Clinical evidence and structural neuroimaging studies linked cerebellar deficits to cognitive-related symptoms in schizophrenia. Yet, in functional neuroimaging literature to date, the role of the cerebellum in schizophrenia was not explored in a systematic fashion. Here, we reviewed 234 functional magnetic resonance imaging studies indexed by PubMed and published in 1997-2010 that had at least one group of schizophrenia patients, used blood oxygenation level dependent contrast and the general linear model to assess neuronal activity.

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This review presents the results of studies carried out in our laboratory that aim to investigate, through functional magnetic resonance imaging (fMRI), the brain plasticity associated with motor sequence learning, defined as our ability to integrate simple stereotyped movements into a single motor representation. Following a brief description of Doyon and colleagues' model (2002, 2005, 2009) of motor skill learning that has guided this work, we then describe the functional changes that occur at the different (rapid, slow, automatization) acquisition phases, and propose specific roles that the putamen, the cerebellum and their motor-related cortical areas, play in this form of motor behavior. Finally, we put forward evidence that post-training, non-REM sleep (and spindles in Stage 2 sleep, in particular) contributes to the consolidation of a motor sequence memory trace, and that increased activity within the striatum and/or the hippocampus mediates this mnemonic process.

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Slow waves (SW; < 4 Hz and > 75 μV) during non-rapid eye movement (NREM) sleep in humans are characterized by hyperpolarization [surface electroencephalogram (EEG) SW negative phase], during which cortical neurons are silent, and depolarization (surface EEG positive phase), during which the cortical neurons fire intensively. We assessed the effects of age, sex and topography on the dynamics of SW characteristics in a large population (n=87) of healthy young (23.3 ± 2.

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This study aimed to investigate, through functional MRI (fMRI), the neuronal substrates associated with the consolidation process of two motor skills: motor sequence learning (MSL) and motor adaptation (MA). Four groups of young healthy individuals were assigned to either (i) a night/sleep condition, in which they were scanned while practicing a finger sequence learning task or an eight-target adaptation pointing task in the evening (test) and were scanned again 12 h later in the morning (retest) or (ii) a day/awake condition, in which they were scanned on the MSL or the MA tasks in the morning and were rescanned 12 h later in the evening. As expected and consistent with the behavioral results, the functional data revealed increased test-retest changes of activity in the striatum for the night/sleep group compared with the day/awake group in the MSL task.

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Study Objectives: To investigate polysomnographic (PSG) sleep and NREM sleep characteristics, including sleep spindles and spectral activity involved in offline consolidation of a motor sequence learning task.

Design: Counterbalanced within-subject design.

Setting: Three weekly visits to the sleep laboratory.

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