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Publications
Publications (110)
White matter pathways, typically studied with diffusion tensor imaging (DTI), have been implicated in the neurobiology of obsessive-compulsive disorder (OCD). However, due to limited sample sizes and the predominance of single-site studies, the generalizability of OCD classification based on diffusion white matter estimates remains unclear. Here, w...
In neurosurgery, spatial normalization emerged as a tool to minimize inter-subject variability and study target point locations based on standard coordinates. The Montreal Neurological Institute's 152 brain template (MNI152) has become the most widely utilized in neuroimaging studies, but has been noted to introduce partial volume effects, distorti...
In genetics, aggregation of many loci with small effect sizes into a single score improved prediction. Nevertheless, studies applying easily replicable weighted scores to neuroimaging data are lacking. Our aim was to assess the reliability and validity of the Neuroimaging Association Score (NAS), which combines information from structural brain fea...
Obsessive-compulsive disorder (OCD) is a common psychiatric condition classically characterized by obsessions (recurrent, intrusive and unwanted thoughts) and compulsions (excessive, repetitive and ritualistic behaviors or mental acts). OCD is heterogeneous in its clinical presentation and not all patients respond to first-line treatments. Several...
Environmental factors are at least as important as genetic factors for the development of obsessive–compulsive symptoms (OCS), but the identification of such factors remain a research priority. Our study aimed to investigate the association between a broad scope of potential risk factors and OCS in a large community cohort of children and adolescen...
An important challenge in mental health research is to translate findings from cognitive neuroscience and neuroimaging research into effective treatments that target the neurobiological alterations involved in psychiatric symptoms. To address this challenge, in this review we propose a heuristic neurocircuit-based taxonomy to guide the treatment of...
Background
Neuropsychiatric symptoms (NPS) are significant manifestations of dementia, with important consequences for patients and caregivers. Despite the established genetic link between Down syndrome (DS) and Alzheimer’s disease (AD), studies investigating NPS in individuals with DS and dementia are scarce. The Neuropsychiatric Inventory (NPI) w...
Background:
Cognitive performance has been studied in adults with obsessive-compulsive symptoms (OCS) and in adult relatives of patients with obsessive-compulsive disorder (OCD) Meanwhile, few studies have been conducted with children under the same conditions. This study compared the neurocognitive domains previously associated with dysfunction i...
Objective
Research on potential brain circuit abnormalities in binge eating disorder (BED) is limited. Here, we assess white matter (WM) microstructure in obese women with BED.
Method
Diffusion tensor imaging data were acquired, and tract‐based spatial statistics used to examine WM in women with BED who were obese (n = 17) compared to normal‐weigh...
Behavioral evidence of impaired response inhibition (RI) and hyperactive error monitoring (EM) in obsessive-compulsive disorder (OCD) is inconsistent. Recent neuroimaging work suggests that EM plays a role in RI impairments in OCD, but this has rarely been investigated using behavioral measures. The aims of this study were to (1) compare RI and EM...
The presence of age-related neuropathology characteristic of Alzheimer‧s disease (AD) in people with Down syndrome (DS) is well-established. However, the early symptoms of dementia may be atypical and appear related to dysfunction of pre-frontal circuitry.
Objective:
To characterize the initial informant reported age-related neuropsychiatric symp...
Background
Cognitive performance has been studied in subclinical obsessive-compulsive (OC) adults and in adults relatives of OCD patients. Meanwhile, no study has been conducted with children under the same conditions. Across a sample with 49 participants, we investigated whether children and adolescents at high-risk (HR) for OCD (n=18) would prese...
The impact of early life stress on mental health and telomere length shortening have been reported. Changes in brain default mode network (DMN) were found to be related to a myriad of psychiatric conditions in which stress may play a role. In this context, family environment and adverse childhood experiences (ACEs) are potential causes of stress. T...
Research suggested accumulation of tau proteins might lead to the degeneration of functional networks. Studies investigating the impact of genetic risk for Alzheimer's disease (AD) on early brain connections might shed light on mechanisms leading to AD development later in life. Here, we aim to investigate whether the polygenic risk score for Alzhe...
The family environment in childhood has a strong effect on mental health outcomes throughout life. This effect is thought to depend at least in part on modifications of neurodevelopment trajectories. In this exploratory study, we sought to investigate whether a feasible resting-state fMRI metric of local spontaneous oscillatory neural activity, the...
Obsessive-compulsive disorder (OCD) is a psychiatric disorder characterized by obsessions and/or compulsions. Different striatal subregions belonging to the cortico-striato-thalamic circuitry (CSTC) play an important role in the pathophysiology of OCD. The transcriptomes of 3 separate striatal areas (putamen (PT), caudate nucleus (CN) and accumbens...
Neurobiological models have provided consistent evidence of the involvement of cortical–subcortical circuitry in obsessive–compulsive disorder (OCD). The orbitofrontal cortex (OFC), involved in motivation and emotional responses, is an important regulatory node within this circuitry. However, OFC abnormalities at the cellular level have so far not...
Diffusion tensor imaging (DTI) studies showed that microstructural alterations are correlated to reading skills. Here, we aim to investigate white matter microstructure of a group of Portuguese speakers with poor reading level, using different parameters of DTI. To perform this analysis we selected children ranging from 8-12 years of age, poor read...
Background:
Frontostriatal and frontoamygdalar connectivity alterations in patients with obsessive-compulsive disorder (OCD) have been typically described in functional neuroimaging studies. However, structural covariance, or volumetric correlations across distant brain regions, also provides network-level information. Altered structural covarianc...
Abnormal connectivity patterns have frequently been reported as involved in pathological mental states. However, most studies focus on "static," stationary patterns of connectivity, which may miss crucial biological information. Recent methodological advances have allowed the investigation of dynamic functional connectivity patterns that describe n...
Individual differences are important biological predictors for reactivity to stressful stimulation. The extent to which trait differences underlie animal's reactions to conditioned and unconditioned fear stimuli, for example, is still to be clarified. Although grooming behavior has been associated with some aspects of the obsessive-compulsive disor...
Objective:
Patients with obsessive-compulsive disorder (OCD) often present with deficits in episodic memory, and there is evidence that these difficulties may be secondary to executive dysfunction, that is, impaired selection and/or application of memory-encoding strategies (mediation hypothesis). Semantic clustering is an effective strategy to en...
The human default mode (DMN) is involved in a wide array of mental disorders. Current knowledge suggests that mental health disorders may reflect deviant trajectories of brain maturation.
We studied 654 children using functional magnetic resonance imaging (fMRI) scans under a resting-state protocol. A machine-learning method was used to obtain age...
Pediatric-onset obsessive-compulsive disorder (OCD) is underdiagnosed, and many affected children are untreated. The present study seeks to evaluate the presence and the clinical impact of OCD and obsessive-compulsive symptoms (OCS) in a large sample of school-age children. In Phase I, we performed an initial screening using the Family History Scre...
Neuromodulation techniques for obsessive-compulsive disorder (OCD) treatment have expanded with greater understanding of the brain circuits involved. Transcranial direct current stimulation (tDCS) might be a potential new treatment for OCD, although the optimal montage is unclear.
To perform a systematic review on meta-analyses of repetitive transc...
Background
Early prediction of treatment response could reduce exposure to ineffective treatments and optimize the use of medical resources. Neuroimaging techniques have been used to identify biomarkers that are predictive of outcomes. The aims of this study were to investigate orbitofrontal cortex (OFC) thickness as a potential morphometric biomar...
Sensory phenomena (SP) are uncomfortable feelings, including bodily sensations, sense of inner tension, "just-right" perceptions, feelings of incompleteness, or "urge-only" phenomena, which have been described to precede, trigger or accompany repetitive behaviours in individuals with obsessive-compulsive disorder (OCD). Sensory phenomena are also o...
Gamma Ventral Capsulotomy (GVC) radiosurgery is intended to minimize side effects while maintaining the efficacy of traditional thermocoagulation techniques for the treatment of refractory Obsessive-Compulsive Disorder (OCD). Neuropsychological outcomes are not clear based on previous studies, and therefore we investigated the effects of GVC on cog...
Background
The investigation of neurodevelopment during late childhood and pre-adolescence has recently attracted a great deal of interest in the field of neuroimaging. One promising topic in this field is the formation of brain networks in healthy subjects. The integration between neural modules characterizes the ability of the network to process...
Importance
Select cases of intractable obsessive-compulsive disorder (OCD) have undergone neurosurgical ablation for more than half a century. However, to our knowledge, there have been no randomized clinical trials of such procedures for the treatment of any psychiatric disorder.Objective
To determine the efficacy and safety of a radiosurgery (g...
Background: The association of late-life depression with both systemic low-grade inflammation and cognitive impairment is well established, however the relation between inflammation and cognition in depressed older persons is still unclear. Neutrophil Gelatinase-Associated Lipocalin (NGAL) has recently been identified as neuroinflammatory component...
Unlabelled:
OBJECT.: Recent findings have suggested a correlation between obsessive-compulsive disorder (OCD) symptom dimensions and clinical outcome after limbic system surgery for treatment-refractory patients. Based on previous evidence that the hoarding dimension is associated with worse outcome in conventional treatments, and may have a neura...
Objective:
Results from structural neuroimaging studies of obsessive-compulsive disorder (OCD) have been only partially consistent. The authors sought to assess regional gray and white matter volume differences between large samples of OCD patients and healthy comparison subjects and their relation with demographic and clinical variables.
Method:...
The goals of the present study were to determine the prevalence of depression in the adult population of Sao Paulo, Brazil and to explore the relationship among sociodemographic, physical and psychological factors, sleep-related symptoms and polysomnography parameters. Participants of a cross-sectional study (N=1101) were administered questionnaire...
To compare the dopaminergic neuronal imaging features of different subtypes of genetic Parkinson's Disease.
A retrospective study of genetic Parkinson's diseases cases in which DaTSCAN (123I-FP-CIT) had been performed. Specific non-displaceable binding was calculated for bilateral caudate and putamen for each case. The right:left asymmetry index an...
Attention-deficit/hyperactivity disorder (ADHD) and substance use disorders (SUD) frequently co-occur. Although several studies have shown changes in striatal dopamine transporter (DAT) density in these disorders, little is known about the neurobiological basis of the comorbidity. The aim of this study was to evaluate striatal DAT density in treatm...
BACKGROUND: Recently, machine learning methods have been used to discriminate, on an individual basis, patients from healthy controls through brain structural magnetic resonance imaging (MRI). However, the application of these methods to predict the severity of psychiatric symptoms is less common. METHODS: Herein, support vector regression (SVR) wa...
Background:
Several studies have demonstrated increased substantia nigra (SN) echogenicity in Parkinson's disease (PD) and Machado-Joseph disease (MJD). Pathological substrate of PD is characterized by dopaminergic nigrostriatal cell loss, also found in MJD. Also, SN hyperechogenicity might be associated with nigrostriatal dysfunction in PD, when...
The application of graph analysis methods to the topological organization of brain connectivity has been a useful tool in the characterization of brain related disorders. However, the availability of tools, which enable researchers to investigate functional brain networks, is still a major challenge. Most of the studies evaluating brain images are...
The investigation of neural substrates of autism spectrum disorder using neuroimaging has been the focus of recent literature. In addition, machine-learning approaches have also been used to extract relevant information from neuroimaging data. There are only few studies directly exploring the inter-regional structural relationships to identify and...
Objectives:
Sleep disorders, especially restless legs syndrome (RLS) and rapid eye movement sleep behavior disorder (RBD), are common in spinocerebellar ataxia type 3 or Machado-Joseph disease (MJD), and a possible underlying dopaminergic dysfunction is implicated. This study assessed the relationship between sleep disorders in MJD and dopamine tr...
Studies based on functional magnetic resonance imaging (fMRI) during the resting state have shown decreased functional connectivity between the dorsal anterior cingulate cortex (dACC) and regions of the Default Mode Network (DMN) in adult patients with Attention-Deficit/Hyperactivity Disorder (ADHD) relative to subjects with typical development (TD...
Attention Deficit/Hyperactivity Disorder (ADHD) is a neurodevelopmental disorder, being one of the most prevalent psychiatric disorders in childhood. The neural substrates associated with this condition, both from structural and functional perspectives, are not yet well established. Recent studies have highlighted the relevance of neuroimaging not...
Nearly one-third of patients with obsessive-compulsive disorder (OCD) fail to respond to adequate therapeutic approaches such as serotonin reuptake inhibitors and/or cognitive-behavioral therapy (CBT). This study investigated structural magnetic resonance imaging (MRI) correlates as potential pre-treatment brain markers to predict treatment respons...
To identify neuropsychological predictors of treatment response to cognitive-behavioral therapy (CBT) and fluoxetine in treatment-naïve adults with obsessive-compulsive disorder (OCD).
Thirty-eight adult outpatients with OCD underwent neuropsychological assessment, including tasks of intellectual function, executive functioning and visual and verba...
Some evidence suggests a hyperdopaminergic state in posttraumatic stress disorder (PTSD). The 9-repetition allele (9R) located in the 3' untranslated region of the dopamine transporter (DAT) gene (SLC6A3) is more frequent among PTSD patients. In vivo molecular imaging studies have shown that healthy 9R carriers have increased striatal DAT binding....
Anxiety is an important component of the psychopathology of the obsessive-compulsive disorder (OCD). So far, most interventions that have proven to be effective for treating OCD are similar to those developed for other anxiety disorders. However, neurobiological studies of OCD came to conclusions that are not always compatible with those previously...
Cognitive and olfactory impairments have been demonstrated in patients with Machado-Joseph disease (MJD), and a possible relationship with dopaminergic dysfunction is implicated. However, there is still controversy regarding the pattern of striatal dopaminergic dysfunction in patients with MJD. In this study, we investigated whether these patients...
Serotonin reuptake inhibitors and cognitive-behavior therapy (CBT) are considered first-line treatments for obsessive-compulsive disorder (OCD). However, little is known about their modulatory effects on regional brain morphology in OCD patients. We sought to document structural brain abnormalities in treatment-naive OCD patients and to determine t...
Attention deficit/hyperactivity disorder (ADHD) is one of the most frequent behavioral problems in school-age children. Although the etiology remains unclear, the involvement of the dopaminergic system has been suggested by genetic studies that report an overexpression of the dopamine transporter (DAT) gene. In spite of these abnormalities being di...
Attention-deficit/hyperactivity disorder (ADHD) and substance use disorders (SUDs) are highly comorbid and may share a genetic vulnerability. Methylphenidate (MPH), a dopamine transporter (DAT) blocker, is an effective drug for most ADHD patients. Although dopamine D4 receptor (DRD4) and dopamine transporter (DAT1) genes have a role in both disorde...
Depression is a frequent non-motor symptom in Parkinson's disease (PD) with increasing rates with the progression of the disease. Molecular imaging studies have shown a reduction of dopamine transporter (DAT) density in depressed PD patients (dPD); however, DAT role in the pathophysiology of PD depression is not clear since clinical matching was in...
To evaluate patients with "clinically established" psychogenic parkinsonism (PsyP) using single-photon emission computer tomography (SPECT) with the technetium-99m labeled tracer TRODAT-1, a dopamine transporter (DAT) ligand, and investigate whether these patients have an underlying degenerative parkinsonism.
Five patients with PsyP were assessed u...
Despite its relatively high prevalence Parkinson's Disease (PD) is still misdiagnosed in approximately 25% of cases. In this study our aim was to evaluate patients with Clinically Unclear Parkinsonian Syndromes (CUPS) submitted to brain SPECT imaging using the technetium-99m labeled Dopamine Transporter (DAT) tracer TRODAT-1. We recruited 15 subjec...