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1.
Neurobiol Aging ; 86: 27-38, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31733943

RESUMO

Ventricular enlargement (VE) is commonly observed in aging and fragile X-associated tremor/ataxia syndrome (FXTAS), a late-onset neurodegenerative disorder. VE may generate a mechanical force causing structural deformation. In this longitudinal study, we examined the relationships between VE and structural changes in the corpus callosum (CC) and putamen. MRI scans (2-7/person over 0.2-7.5 years) were acquired from 22 healthy controls, 26 unaffected premutation carriers (PFX-), and 39 carriers affected with FXTAS (PFX+). Compared with controls, PFX- demonstrated enlarged fourth ventricles, whereas PFX+ displayed enlargement in both third and fourth ventricles, CC thinning, putamen atrophy/deformation (thinning and increased distance), and accelerated expansions in lateral ventricles. Common for all groups, baseline VE predicted accelerated CC thinning and putamen atrophy/deformation and conversely, baseline CC and putamen atrophy/deformation and enlarged third and fourth ventricles predicted accelerated lateral ventricular expansion. The results suggest a progressive VE within the 4 ventricles as FXTAS develops and a deleterious cycle between VE and brain deformation that may commonly occur during aging and FXTAS progression but become accelerated in FXTAS.

2.
Front Psychiatry ; 10: 810, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31780970

RESUMO

Objective: Selective serotonin reuptake inhibitors like sertraline have been shown in observational studies and anecdotal reports to improve language development in young children with fragile X syndrome (FXS). A previous controlled trial of sertraline in young children with FXS found significant improvement in expressive language development as measured by the Mullen Scales of Early Learning (MSEL) among those with comorbid autism spectrum disorder (ASD) in post hoc analysis, prompting the authors to probe whether sertraline is also indicated in nonsyndromic ASD. Methods: The authors evaluated the efficacy of 6 months of treatment with low-dose sertraline in a randomized, double-blind, placebo-controlled trial in 58 children with ASD aged 24 to 72 months. Results: 179 subjects were screened for eligibility, and 58 were randomized to sertraline (32) or placebo (26). Eight subjects from the sertraline arm and five from the placebo arm discontinued. Intent-to-treat analysis showed no significant difference from placebo on the primary outcomes (MSEL expressive language raw score and age equivalent combined score) or secondary outcomes. Sertraline was well tolerated, with no difference in side effects between sertraline and placebo groups. No serious adverse events possibly related to study treatment occurred. Conclusion: This randomized controlled trial of sertraline treatment showed no benefit with respect to primary or secondary outcome measures. For the 6-month period, treatment in young children with ASD appears safe, although the long-term side effects of low-dose sertraline in early childhood are unknown. Clinical Trial Registration: www.ClinicalTrials.gov, identifier NCT02385799.

3.
Mol Genet Genomic Med ; 7(11): e956, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31520524

RESUMO

BACKGROUND: Metformin is a drug commonly used in individuals with type 2 diabetes, obesity, and impaired glucose tolerance. It has a strong safety profile in both children and adults. Studies utilizing the Drosophila model and knock out mouse model of fragile X syndrome (FXS) have found metformin to rescue memory, social novelty deficits, and neuroanatomical abnormalities. These studies provided preliminary evidence that metformin could be used as a targeted treatment for the cognitive and behavioral problems associated with FXS. Previously, a case series of children and adults with FXS treated with metformin demonstrated improvements in irritability, social responsiveness, language, and hyperactivity. METHODS: Here, we present nine children with FXS between 2 and 7 years of age who were treated clinically with metformin and monitored for behavioral and metabolic changes. RESULTS: Parent reports and developmental testing before and after metformin are presented. There were improvements in language development and behavior (such as lethargy and stereotypy) in most of the patients. CONCLUSION: These results support the need for a controlled trial of metformin in children with FXS under 7 years old whose brains are in a critical developmental window and thus may experience a greater degree of clinical benefit from metformin.

4.
Front Psychol ; 10: 1567, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31354578

RESUMO

Fragile X syndrome (FXS) is a genetic disorder caused by a trinucleotide CGG expansion within the FMR1 gene located on the X chromosome. Children with FXS have been shown to be impaired in dynamic visual attention processing. A key component of dynamic processing is orienting-a perceptual ability that requires disengagement and engagement of attention from one stimulus to fixate on a second. Orienting, specifically the disengagement and engagement of attention, has previously not been studied in young children with FXS. Using an eye tracking gap-overlap task, the present study investigated visual disengagement and engagement in young children with FXS, compared to mental age (MA)- and chronological age (CA)-matched typically developing children. On gap trials, the central stimulus elicited fixation, but then disappeared before the peripheral target appeared, imposing a visual gap between stimuli. On overlap trials, the central stimulus elicited fixation, and remained present when the peripheral target appeared, creating visual competition. A gap effect emerges when latencies to shift to the peripheral target are longer in overlap versus gap conditions, reflecting the recruitment of cortical and subcortical disengagement and engagement mechanisms. The gap effect was measured as the latency to orient attention to the peripheral target during gap versus overlap conditions. Both MA and CA groups showed the expected gap effect, where children were slower to orient to peripheral targets on overlap trials than on gap trials. In contrast, in the FXS group, saccadic latencies between gap and overlap trials were not significantly different, indicating no significant gap effect. These findings suggest disrupted attentional engagement patterns in FXS that may be underlying impairments in attention orienting, and suggest potential targets for attention training in this population.

5.
Autism Res ; 12(8): 1236-1250, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31157516

RESUMO

Autism spectrum disorder (ASD), characterized by impairments in social communication and repetitive behaviors, often includes altered responses to sensory inputs as part of its phenotype. The neurobiological basis for altered sensory processing is not well understood. The UC Davis Medical Investigation of Neurodevelopmental Disorders Institute Autism Phenome Project is a longitudinal, multidisciplinary study of young children with ASD and age-matched typically developing (TD) controls. Previous analyses of the magnetic resonance imaging data from this cohort have shown that ∼15% of boys with ASD have disproportionate megalencephaly (DM) or brain size to height ratio, that is 1.5 standard deviations above the TD mean. Here, we investigated electrophysiological responses to auditory stimuli of increasing intensity (50-80 dB) in young toddlers (27-48 months old). Analyses included data from 36 age-matched boys, of which 24 were diagnosed with ASD (12 with and 12 without DM; ASD-DM and ASD-N) and 12 TD controls. We found that the two ASD subgroups differed in their electrophysiological response patterns to sounds of increasing intensity. At early latencies (55-115 ms), ASD-N does not show a loudness-dependent response like TD and ASD-DM, but tends to group intensities by soft vs. loud sounds, suggesting differences in sensory sensitivity in this group. At later latencies (145-195 ms), only the ASD-DM group shows significantly higher amplitudes for loud sounds. Because no similar effects were found in ASD-N and TD groups, this may be related to their altered neuroanatomy. These results contribute to the effort to delineate ASD subgroups and further characterize physiological responses associated with observable phenotypes. Autism Res 2019, 12: 1236-1250. © 2019 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: Approximately 15% of boys with ASD have much bigger brains when compared to individuals with typical development. By recording brain waves (electroencephalography) we compared how autistic children, with or without big brains, react to sounds compared to typically developing controls. We found that brain responses in the big-brained group are different from the two other groups, suggesting that they represent a specific autism subgroup.

6.
Front Neurol ; 9: 695, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30186228

RESUMO

Here we report five cases of male FMR1 premutation carriers who present without clinical symptoms of the fragile X-associated tremor/ataxia syndrome (FXTAS), but who on MRI demonstrate white matter hyperintensities in the middle cerebellar peduncles (MCP sign) and other brain regions, a rare finding. MCP sign is the major radiological feature of FXTAS; it is therefore remarkable to identify five cases in which this MRI finding is present in the absence of tremor and ataxia, the major clinical features of FXTAS. Subjects underwent a detailed neurological evaluation, neuropsychological testing, molecular testing, and MRI evaluation utilizing T2 imaging described here. Additional white matter disease was present in the corpus callosum in four of the five cases. However, all cases were asymptomatic for motor signs of FXTAS.

7.
Front Genet ; 9: 302, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30186307

RESUMO

Approximately 30-40% of male and 8-16% of female carriers of the Fragile X premutation will develop a neurodegenerative movement disorder characterized by intentional tremor, gait ataxia, autonomic dysfunction, cognitive decline, and Parkinsonism during their lifetime. At the molecular level, premutation carriers have increased expression levels of the FMR1 and the antisense FMR1 (ASFMR1) mRNAs. Both genes undergo alternative splicing giving rise to a number of different transcripts. Alteration in the alternative splicing process might be associated with FXTAS. In this study, we have investigated the correlation between objective measures of movement (balance and tremor using the CATSYS battery) and the expression of both the FMR1 and the ASFMR1 genes. In addition, we investigated whether their expression level and that of the ASFMR1 131 bp splice isoform could distinguish between premutation carriers with FXTAS and non-FXTAS premutation carriers. Confirming previous findings, the expression levels of transcripts at the FMR1 locus positively correlated with the CGG repeat number and significantly differentiated the premutation carriers from the control groups. Furthermore, premutation carriers with and without FXTAS, showed a significant difference in the expression level of the ASFMR1 131 bp splice isoform when compared to age and gender matched controls. However, there was no significant difference in the ASFMR1 131 bp splice isoform expression level when comparing premutation carriers with and without FXTAS. Finally, our results indicate significant group differences in CATSYS dominant hand reaction time and postural sway with eyes closed in premutation carriers without FXTAS compared to controls. In addition, a significant inverse association between the tremor intensity and the expression level of ASFMR1 131 bp splice isoform in premutation carriers compared to controls, was observed, suggesting a potential role in the pathogenesis of FXTAS.

8.
Front Neurosci ; 12: 379, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29988561

RESUMO

Fragile X-associated tremor/ataxia syndrome (FXTAS) is a severe neurodegenerative movement disorder affecting over 40% of male and 16% of female FMR1 premutation carriers over the age of 50. However, there is a lack of prognostic biomarkers to aid early diagnosis and treatment planning. Therefore, this study aimed to assess the utility of the Magnetic Resonance Parkinson Index (MRPI) as a potential MRI biomarker for FXTAS. The four measurements required for the MRPI were assessed in 45 male premutation carriers at risk of developing FXTAS (Mean age = 59.54 years), 53 male patients with FXTAS (Mean age = 66.16 years) and 61 male controls (Mean age = 60.75 years), of which 73 participants had follow-up visits on average 1.96 years later. Middle cerebellar peduncle (MCP) width as well as midbrain and pons cross-sectional area were reduced in patients with FXTAS compared to both premutation carriers without FXTAS and controls. While these measurements were not found to change over time in the three-group analysis, age was an important predictor of midbrain cross-sectional area and pons/midbrain ratio. MCP width was initially reduced in a subset of premutation carriers who developed FXTAS symptoms between their initial and follow-up visits, which also decreased between visits, compared to age-matched premutation carriers who did not show any FXTAS symptom development over time. Therefore, while the MPRI may not be a useful biomarker for FXTAS, decreased MCP width may be one of the first notable signs of FXTAS, and therefore the first biomarker with the potential to identify those most at risk for the disorder.

9.
Mov Disord ; 33(4): 628-636, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29389022

RESUMO

BACKGROUND: Fragile X premutation carriers are at increased risk for fragile X-associated tremor ataxia syndrome (FXTAS), but to date we know little about prediction of onset and rate of progression and even less about treatment of this neurodegenerative disease. Thus, the longitudinal study of carriers, and the identification of potential biomarkers and prodromal states, is essential. Here we present results of baseline assessments from an ongoing longitudinal project. METHODS: The cohort consisted of 73 men, 48 with the fragile X mental retardation 1 (FMR1) premutation (55-200 cytosine-cytosine-guanine or CGG repeats) and 25 well-matched controls (< 40 repeats) aged between 40 and 75 years. At enrollment, none met criteria for FXTAS or had any clinically significant tremor or ataxia by blinded neurological examination. The battery consisted of measures of visual memory, spatial working memory, response inhibition, motor speed and control, planning and problem solving, sustained attention, and a standardized movement disorder evaluation. RESULTS: Contrary to expectations, there were no significant differences between premutation carriers and controls on any measure of executive function. However, the premutation carriers had significantly longer manual movement and reaction times than controls, and the significant interaction between CGG repeat and age revealed the slowest movement times among older carriers with higher CGG repeat alleles. A subset of premutation carriers had marginally lower scores on the ataxia evaluation, and they performed no differently from controls on the parkinsonism assessment. CONCLUSION: Early-developing cerebellar or fronto-motor tract white matter changes, previously documented in MRI studies, may underlie motor slowing that occurs before clinically observable neurological symptoms associated with FXTAS. © 2018 International Parkinson and Movement Disorder Society.


Assuntos
Envelhecimento , Ataxia/genética , Proteína do X Frágil de Retardo Mental/genética , Síndrome do Cromossomo X Frágil/genética , Sintomas Prodrômicos , Tremor/genética , Expansão das Repetições de Trinucleotídeos/genética , Adulto , Fatores Etários , Idoso , Ataxia/complicações , Atenção , Estudos de Coortes , Feminino , Síndrome do Cromossomo X Frágil/complicações , Humanos , Inteligência , Masculino , Transtornos da Memória/etiologia , Memória de Curto Prazo/fisiologia , Pessoa de Meia-Idade , Estimulação Luminosa , RNA Mensageiro/metabolismo , Tempo de Reação , Análise de Regressão , Tremor/complicações
10.
J Autism Dev Disord ; 48(3): 809-823, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29168088

RESUMO

Understanding another's actions, including what they are doing and why they are doing it, can be difficult for individuals with autism spectrum disorder (ASD). This understanding is supported by the action observation (AON) and mentalizing (MZN) networks, as well as the superior temporal sulcus. We examined these areas in children with ASD and typically developing controls by having participants view eating and placing actions performed in conventional and unconventional ways while functional magnetic resonance images were collected. We found an effect of action-type, but not conventionality, in both groups, and a between groups difference only when viewing conventional eating actions. Findings suggest there are not global AON/MZN deficits in ASD, and observing unconventional actions may not spontaneously activate the MZN.


Assuntos
Comportamento do Adolescente/psicologia , Transtorno do Espectro Autista/diagnóstico por imagem , Encéfalo/diagnóstico por imagem , Compreensão , Rede Nervosa/diagnóstico por imagem , Percepção Visual , Adolescente , Comportamento do Adolescente/fisiologia , Transtorno do Espectro Autista/fisiopatologia , Transtorno do Espectro Autista/psicologia , Encéfalo/fisiopatologia , Criança , Compreensão/fisiologia , Feminino , Humanos , Imagem por Ressonância Magnética/métodos , Masculino , Rede Nervosa/fisiopatologia , Estimulação Luminosa/métodos , Teoria da Mente/fisiologia , Percepção Visual/fisiologia
11.
eNeurologicalSci ; 7: 49-56, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28971146

RESUMO

The prevalence of the fragile X premutation (55-200 CGG repeats) among the general population is relatively high, but there remains a lack of clear understanding of the links between molecular biomarkers and clinical outcomes. In this study we investigated the correlations between molecular measures (CGG repeat size, FMR1 mRNA, FMRP expression levels, and methylation status at the promoter region and in FREE2 site) and clinical phenotypes (anxiety, obsessive compulsive symptoms, depression and executive function deficits) in 36 adult premutation female carriers and compared to 24 normal control subjects. Premutation carriers reported higher levels of obsessive compulsive symptoms, depression, and anxiety, but demonstrated no significant deficits in global cognitive functions or executive function compared to the control group. Increased age in carriers was significantly associated with increased anxiety levels. As expected, FMR1 mRNA expression was significantly correlated with CGG repeat number. However, no significant correlations were observed between molecular (including epigenetic) measures and clinical phenotypes in this sample. Our study, albeit limited by the sample size, establishes the complexity of the mechanisms that link the FMR1 locus to the clinical phenotypes commonly observed in female carriers suggesting that other factors, including environment or additional genetic changes, may have an impact on the clinical phenotypes. However, it continues to emphasize the need for assessment and treatment of psychiatric problems in female premutation carriers.

12.
Dev Psychol ; 53(8): 1418-1427, 2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-28530439

RESUMO

This study examines attentional biases in the presence of angry, happy and neutral faces using a modified eye tracking version of the dot probe task (DPT). Participants were 111 young children between 9 and 48 months. Children passively viewed an affective attention bias task that consisted of a face pairing (neutral paired with either neutral, angry or happy) for 500 ms that was followed by a 1,500-ms asterisk probe on 1 side of the screen. Congruent trials were trials in which the probe appeared on the same side of the screen as the emotional face and incongruent trials were trials in which the probe appeared on the opposite side of the emotional face. The latency to fixate on the probe, rather than the traditional task's button press latency, was measured for both types of trials and a bias score was calculated by subtracting the latency to the probe on congruent trials from that on incongruent trials. The results of the current study indicate positive internal reliability of this modified version of the DPT as well as the presence of a bias toward both angry and happy faces during the first 4 years of life. The successful use of the modified version of the DPT for use on the eye tracker presents a promising methodological tool for research on early attentional behavior and provides a tool for comprehensive longitudinal studies of identified risk factors for anxiety. (PsycINFO Database Record


Assuntos
Viés de Atenção/fisiologia , Desenvolvimento Infantil/fisiologia , Emoções/fisiologia , Movimentos Oculares/fisiologia , Face , Fatores Etários , Pré-Escolar , Feminino , Humanos , Lactente , Masculino , Estimulação Luminosa , Tempo de Reação/fisiologia , Reprodutibilidade dos Testes , Fatores de Tempo
13.
Neurobiol Aging ; 55: 11-19, 2017 07.
Artigo em Inglês | MEDLINE | ID: mdl-28391068

RESUMO

Fragile X-associated tremor/ataxia syndrome (FXTAS) is a late-onset neurodegenerative disorder typically affecting male premutation carriers with 55-200 CGG trinucleotide repeat expansions in the FMR1 gene after age 50. The aim of this study was to examine whether cerebellar and brainstem changes emerge during development or aging in late life. We retrospectively analyzed magnetic resonance imaging scans from 322 males (age 8-81 years). Volume changes in the cerebellum and brainstem were contrasted with those in the ventricles and whole brain. Compared to the controls, premutation carriers without FXTAS showed significantly accelerated volume decrease in the cerebellum and whole brain, flatter inverted U-shaped trajectory of the brainstem, and larger ventricles. Compared to both older controls and premutation carriers without FXTAS, carriers with FXTAS exhibited significant volume decrease in the cerebellum and whole brain and accelerated volume decrease in the brainstem. We therefore conclude that cerebellar and brainstem volumes were likely affected during both development and progression of neurodegeneration in premutation carriers, suggesting that interventions may need to start early in adulthood to be most effective.


Assuntos
Ataxia/genética , Ataxia/patologia , Tronco Encefálico/diagnóstico por imagem , Tronco Encefálico/patologia , Cerebelo/diagnóstico por imagem , Cerebelo/patologia , Proteína do X Frágil de Retardo Mental/genética , Síndrome do Cromossomo X Frágil/genética , Síndrome do Cromossomo X Frágil/patologia , Heterozigoto , Mutação , Tamanho do Órgão/genética , Tremor/genética , Tremor/patologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Ataxia/diagnóstico por imagem , Atrofia , Criança , Estudos Transversais , Síndrome do Cromossomo X Frágil/diagnóstico por imagem , Expressão Gênica , Humanos , Imagem por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Neuroimagem , RNA Mensageiro/metabolismo , Estudos Retrospectivos , Tremor/diagnóstico por imagem , Expansão das Repetições de Trinucleotídeos , Adulto Jovem
14.
Infant Behav Dev ; 46: 46-58, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27898343

RESUMO

This study examines how social cues facilitate learning by manipulating the familiarity of a social cue. Participants were forty-nine infants between 12-18 months. Infants were taught a novel label for a novel object under two pre-recorded gaze conditions-one in which the caregiver was seen gazing at a novel object while a verbal label was played, and one in which a stranger was seen gazing at a novel object while a verbal label was played. Learning was only evident in the caregiver condition and only in the infants most skilled at following their caregivers' gaze. The results of the current study suggest that both the familiarity of the cuer and the infant's own ability to follow the gaze of the cuer play important roles in the infant's learning in this task.


Assuntos
Cuidadores/psicologia , Fixação Ocular/fisiologia , Comportamento do Lactente/fisiologia , Comportamento do Lactente/psicologia , Aprendizagem/fisiologia , /fisiologia , Atenção/fisiologia , Sinais (Psicologia) , Feminino , Humanos , Lactente , Masculino
15.
Artigo em Inglês | MEDLINE | ID: mdl-29348038

RESUMO

BACKGROUND: Fragile X syndrome (FXS) is the most common form of inherited intellectual disability. FXS is caused by a silencing of the FMR1 gene that results in a loss or absence of the gene's protein product, fragile X mental retardation protein. The phenotype of FXS is consistently associated with heightened anxiety, although no previous study has investigated attentional bias toward threat, a hallmark of anxiety disorders, in individuals with FXS. METHODS: The current study employed a passive-viewing eye-tracking version of the dot probe task to investigate attentional biases toward emotional faces in young children with FXS (n = 47) and without FXS (n = 94). RESULTS: We found that the FXS group showed a significantly greater bias toward threatening emotions than toward positive emotions. This threat specificity was not seen in either a mental age-matched group or a chronological age-matched group of typically developing children. Unlike the typically developing groups, the FXS group showed no bias toward positive emotion. CONCLUSIONS: The current study shows that children with FXS have a significant bias toward threatening information, an attentional profile that has been linked with anxiety. It also supports the use of eye-tracking methodology to index neural and attentional responses in young children with FXS.


Assuntos
Viés de Atenção , Emoções , Medo , Síndrome do Cromossomo X Frágil/psicologia , Pré-Escolar , Medições dos Movimentos Oculares , Expressão Facial , Reconhecimento Facial , Feminino , Humanos , Lactente , Masculino
16.
Am J Med Genet B Neuropsychiatr Genet ; 171(8): 1139-1147, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-27615674

RESUMO

Several studies have demonstrated increased rates of anxiety and depressive disorders among female carriers of the fragile X premutation. However, the majority of these studies focused on mothers of children with fragile X syndrome, who experience higher rates of parenting stress that may contribute to the emergence of these disorders. The present study compared psychiatric symptom presentation (utilizing measures of current symptoms and lifetime DSM-IV Axis I disorders) in 24 female carriers without affected children (mean age = 32.1 years) to 26 non-carrier women from the community (mean age = 30.5 years). We also examined the association between CGG repeat size (adjusted for X activation ratio) and mRNA, with severity of psychiatric symptoms. Women with the premutation reported significantly elevated symptoms of anxiety, depression, interpersonal sensitivity, obsessive-compulsiveness, and somatization relative to controls during the past week. Carriers had significantly higher rates of lifetime social phobia (42.3%) compared to controls (12.5%); however, this comparison did not remain significant after multiple comparison adjustment. Rates of other psychiatric disorders were not significantly elevated relative to controls, though it should be noted that lifetime rates among controls were much higher than previously published population estimates. Although the sample is relatively small, the study of this unique cohort suggests the premutation confers risk for mood and anxiety disorders independent of the stress of parenting children with FXS. Screening for psychiatric disorders in women with the premutation, even before they become parents, is important and highly encouraged. © 2016 Wiley Periodicals, Inc.


Assuntos
Síndrome do Cromossomo X Frágil/genética , Síndrome do Cromossomo X Frágil/psicologia , Adulto , Afeto , Ansiedade/genética , Transtornos de Ansiedade/genética , Depressão/genética , Transtorno Depressivo/genética , Feminino , Proteína do X Frágil de Retardo Mental/genética , Humanos , Transtornos Mentais/etiologia , Transtornos Mentais/genética , Repetições de Trinucleotídeos/genética
17.
PLoS One ; 11(5): e0156123, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27213683

RESUMO

Automated segmentation is a useful method for studying large brain structures such as the cerebellum and brainstem. However, automated segmentation may lead to inaccuracy and/or undesirable boundary. The goal of the present study was to investigate whether SegAdapter, a machine learning-based method, is useful for automatically correcting large segmentation errors and disagreement in anatomical definition. We further assessed the robustness of the method in handling size of training set, differences in head coil usage, and amount of brain atrophy. High resolution T1-weighted images were acquired from 30 healthy controls scanned with either an 8-channel or 32-channel head coil. Ten patients, who suffered from brain atrophy because of fragile X-associated tremor/ataxia syndrome, were scanned using the 32-channel head coil. The initial segmentations of the cerebellum and brainstem were generated automatically using Freesurfer. Subsequently, Freesurfer's segmentations were both manually corrected to serve as the gold standard and automatically corrected by SegAdapter. Using only 5 scans in the training set, spatial overlap with manual segmentation in Dice coefficient improved significantly from 0.956 (for Freesurfer segmentation) to 0.978 (for SegAdapter-corrected segmentation) for the cerebellum and from 0.821 to 0.954 for the brainstem. Reducing the training set size to 2 scans only decreased the Dice coefficient ≤0.002 for the cerebellum and ≤ 0.005 for the brainstem compared to the use of training set size of 5 scans in corrective learning. The method was also robust in handling differences between the training set and the test set in head coil usage and the amount of brain atrophy, which reduced spatial overlap only by <0.01. These results suggest that the combination of automated segmentation and corrective learning provides a valuable method for accurate and efficient segmentation of the cerebellum and brainstem, particularly in large-scale neuroimaging studies, and potentially for segmenting other neural regions as well.


Assuntos
Ataxia/diagnóstico por imagem , Mapeamento Encefálico , Tronco Encefálico/diagnóstico por imagem , Cerebelo/diagnóstico por imagem , Síndrome do Cromossomo X Frágil/diagnóstico por imagem , Processamento de Imagem Assistida por Computador/métodos , Aprendizado de Máquina , Imagem por Ressonância Magnética , Neuroimagem , Tremor/diagnóstico por imagem , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Algoritmos , Ataxia/patologia , Ataxia/fisiopatologia , Ataxia/psicologia , Mapeamento Encefálico/métodos , Mapeamento Encefálico/normas , Tronco Encefálico/patologia , Calibragem , Estudos de Casos e Controles , Cerebelo/patologia , Síndrome do Cromossomo X Frágil/patologia , Síndrome do Cromossomo X Frágil/fisiopatologia , Síndrome do Cromossomo X Frágil/psicologia , Humanos , Processamento de Imagem Assistida por Computador/normas , Imagem por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Neuroimagem/métodos , Neuroimagem/normas , Tremor/patologia , Tremor/fisiopatologia , Tremor/psicologia , Adulto Jovem
18.
Front Psychol ; 6: 1724, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26635651

RESUMO

The investigation of the ability to perceive, recognize, and judge upon social intentions, such as communicative intentions, on the basis of body motion is a growing research area. Cross-cultural differences in ability to perceive and interpret biological motion, however, have been poorly investigated so far. Progress in this domain strongly depends on the availability of suitable stimulus material. In the present method paper, we describe the multilingual CID-5, an extension of the CID-5 database, allowing for the investigation of how non-conventional communicative gestures are classified and identified by speakers of different languages. The CID-5 database contains 14 communicative interactions and 7 non-communicative actions performed by couples of agents and presented as point-light displays. For each action, the database provides movie files with the point-light animation, text files with the 3-D spatial coordinates of the point-lights, and five different response alternatives. In the multilingual CID-5 the alternatives were translated into seven languages (Chinese, Dutch, English, French, German, Italian, and Polish). Preliminary data collected to assess the recognizability of the actions in the different languages suggest that, for most of the action stimuli, information presented in point-light displays is sufficient for the distinctive classification of the action as communicative vs. individual, as well as for identification of the specific communicative gesture performed by the actor in all the available languages.

19.
Front Psychol ; 6: 551, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25999879

RESUMO

Previous research has shown that infants can learn from social cues. But is a social cue more effective at directing learning than a non-social cue? This study investigated whether 9-month-old infants (N = 55) could learn a visual statistical regularity in the presence of a distracting visual sequence when attention was directed by either a social cue (a person) or a non-social cue (a rectangle). The results show that both social and non-social cues can guide infants' attention to a visual shape sequence (and away from a distracting sequence). The social cue more effectively directed attention than the non-social cue during the familiarization phase, but the social cue did not result in significantly stronger learning than the non-social cue. The findings suggest that domain general attention mechanisms allow for the comparable learning seen in both conditions.

20.
Front Hum Neurosci ; 9: 37, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25698960

RESUMO

Carriers of the fragile X premutation allele (fXPCs) have an expanded CGG trinucleotide repeat size within the FMR1 gene and are at increased risk of developing fragile x-associated tremor/ataxia syndrome (FXTAS). Previous research has shown that male fXPCs with FXTAS exhibit cognitive decline, predominantly in executive functions such as inhibitory control and working memory. Recent evidence suggests fXPCs may also exhibit impairments in processing temporal information. The attentional blink (AB) task is often used to examine the dynamics of attentional selection, but disagreements exist as to whether the AB is due to excessive or insufficient attentional control. In this study, we used a variant of the AB task and neuropsychological testing to explore the dynamics of attentional selection, relate AB performance to attentional control, and determine whether fXPCs exhibited temporal and/or attentional control impairments. Participants were adult male fXPCs, aged 18-48 years and asymptomatic for FXTAS (n = 19) and age-matched male controls (n = 20). We found that fXPCs did not differ from controls in the AB task, indicating that the temporal dynamics of attentional selection were intact. However, they were impaired in the letter-number sequencing task, a test of executive working memory. In the combined fXPC and control group, letter-number sequencing performance correlated positively with AB magnitude. This finding supports models that posit the AB is due to excess attentional control. In our two-pronged analysis approach, in control participants we replicated a previously observed effect and demonstrated that it persists under more stringent theoretical constraints, and we enhance our understanding of fXPCs by demonstrating that at least some aspects of temporal processing may be spared.

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