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1.
Eur Child Adolesc Psychiatry ; 32(12): 2523-2536, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36738328

RESUMO

Evidence of alterations in emotion processing in maltreated youth has been hypothesized to reflect latent vulnerability for psychopathology. However, previous studies have not systematically examined the influence of psychopathology on the results. Here, we examined emotion recognition and learning in youth who differed in terms of presence vs. absence of maltreatment and psychopathology and tested for potential sex effects. Maltreatment and psychopathology were assessed in 828 youth (514 females) aged 9-18 years using diagnostic interviews and self- and parent-report questionnaires. Emotion recognition was assessed via identification of morphed facial expressions of six universal emotions. For emotion learning, reward and punishment values were assigned to novel stimuli and participants had to learn to correctly respond/withhold response to stimuli to maximize points. A three-way interaction of maltreatment by psychopathology by emotion indicated that when psychopathology was low, maltreated youth were less accurate than non-maltreated youth for happy, fear and disgust. A three-way interaction of sex, maltreatment and emotion indicated that maltreated girls and boys were impaired for fear, but girls showed an impairment for happy, while boys for disgust. There were no effects of maltreatment, psychopathology, or sex on reward learning. However, a two-way interaction between sex and maltreatment showed that maltreated girls were worse at learning from punishment relative to non-maltreated girls, while maltreated boys were better than non-maltreated boys. The study provides the first clear evidence of latent-vulnerability in emotion recognition in maltreated youth and suggests that girls and boys might be characterized by distinct profiles of emotion recognition and learning following maltreatment.


Assuntos
Maus-Tratos Infantis , Masculino , Criança , Feminino , Adolescente , Humanos , Maus-Tratos Infantis/psicologia , Emoções , Medo , Expressão Facial , Psicopatologia
2.
Eur Child Adolesc Psychiatry ; 32(4): 589-600, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-34661765

RESUMO

Conduct disorder (CD) with high levels of callous-unemotional traits (CD/HCU) has been theoretically linked to specific difficulties with fear and sadness recognition, in contrast to CD with low levels of callous-unemotional traits (CD/LCU). However, experimental evidence for this distinction is mixed, and it is unclear whether these difficulties are a reliable marker of CD/HCU compared to CD/LCU. In a large sample (N = 1263, 9-18 years), we combined univariate analyses and machine learning classifiers to investigate whether CD/HCU is associated with disproportionate difficulties with fear and sadness recognition over other emotions, and whether such difficulties are a reliable individual-level marker of CD/HCU. We observed similar emotion recognition abilities in CD/HCU and CD/LCU. The CD/HCU group underperformed relative to typically developing (TD) youths, but difficulties were not specific to fear or sadness. Classifiers did not distinguish between youths with CD/HCU versus CD/LCU (52% accuracy), although youths with CD/HCU and CD/LCU were reliably distinguished from TD youths (64% and 60%, respectively). In the subset of classifiers that performed well for youths with CD/HCU, fear and sadness were the most relevant emotions for distinguishing them from youths with CD/LCU and TD youths, respectively. We conclude that non-specific emotion recognition difficulties are common in CD/HCU, but are not reliable individual-level markers of CD/HCU versus CD/LCU. These findings highlight that a reduced ability to recognise facial expressions of distress should not be assumed to be a core feature of CD/HCU.


Assuntos
Transtorno da Conduta , Reconhecimento Facial , Adolescente , Humanos , Transtorno da Conduta/diagnóstico , Transtorno da Conduta/psicologia , Emoções , Medo , Reconhecimento Psicológico
3.
Int J Obes (Lond) ; 46(7): 1319-1327, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35397638

RESUMO

BACKGROUND/OBJECTIVES: Intranasal (IN) administration of insulin decreases appetite in humans, but the underlying mechanisms are unclear, and it is unknown whether IN insulin affects the food intake of women with obesity. SUBJECTS/METHODS: In a double-blind, placebo-controlled, crossover design, participants (35 lean women and 17 women with obesity) were randomized to receive 160 IU/1.6 mL of IN insulin or placebo in a counterbalanced order in the post prandial state. The effects of IN insulin on cookie intake, appetite, mood, food reward, cognition and neural activity were assessed. RESULTS: IN insulin in the post prandial state reduced cookie intake, appetite and food reward relative to placebo and these effects were more pronounced for women with obesity compared with lean women. IN insulin also improved mood in women with obesity. In both BMI groups, IN insulin increased neural activity in the insula when viewing food pictures. IN insulin did not affect cognitive function. CONCLUSIONS: These results suggest that IN insulin decreases palatable food intake when satiated by reducing food reward and that women with obesity may be more sensitive to this effect than lean women. Further investigation of the therapeutic potential of IN insulin for weight management in women with obesity is warranted.


Assuntos
Apetite , Pesquisa Biomédica , Administração Intranasal , Método Duplo-Cego , Ingestão de Energia , Feminino , Humanos , Insulina/farmacologia , Obesidade
4.
Dev Psychopathol ; 33(3): 980-991, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-32571444

RESUMO

Less is known about the relationship between conduct disorder (CD), callous-unemotional (CU) traits, and positive and negative parenting in youth compared to early childhood. We combined traditional univariate analyses with a novel machine learning classifier (Angle-based Generalized Matrix Learning Vector Quantization) to classify youth (N = 756; 9-18 years) into typically developing (TD) or CD groups with or without elevated CU traits (CD/HCU, CD/LCU, respectively) using youth- and parent-reports of parenting behavior. At the group level, both CD/HCU and CD/LCU were associated with high negative and low positive parenting relative to TD. However, only positive parenting differed between the CD/HCU and CD/LCU groups. In classification analyses, performance was best when distinguishing CD/HCU from TD groups and poorest when distinguishing CD/HCU from CD/LCU groups. Positive and negative parenting were both relevant when distinguishing CD/HCU from TD, negative parenting was most relevant when distinguishing between CD/LCU and TD, and positive parenting was most relevant when distinguishing CD/HCU from CD/LCU groups. These findings suggest that while positive parenting distinguishes between CD/HCU and CD/LCU, negative parenting is associated with both CD subtypes. These results highlight the importance of considering multiple parenting behaviors in CD with varying levels of CU traits in late childhood/adolescence.


Assuntos
Transtorno da Conduta , Adolescente , Criança , Pré-Escolar , Emoções , Empatia , Humanos , Poder Familiar
5.
Brain ; 142(1): 15-22, 2019 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-30535098

RESUMO

The proportional recovery rule asserts that most stroke survivors recover a fixed proportion of lost function. To the extent that this is true, recovery from stroke can be predicted accurately from baseline measures of acute post-stroke impairment alone. Reports that baseline scores explain more than 80%, and sometimes more than 90%, of the variance in the patients' recoveries, are rapidly accumulating. Here, we show that these headline effect sizes are likely inflated. The key effects in this literature are typically expressed as, or reducible to, correlation coefficients between baseline scores and recovery (outcome scores minus baseline scores). Using formal analyses and simulations, we show that these correlations will be extreme when outcomes are significantly less variable than baselines, which they often will be in practice regardless of the real relationship between outcomes and baselines. We show that these effect sizes are likely to be over-optimistic in every empirical study that we found that reported enough information for us to make the judgement, and argue that the same is likely to be true in other studies as well. The implication is that recovery after stroke may not be as proportional as recent studies suggest.


Assuntos
Recuperação de Função Fisiológica , Estatística como Assunto/métodos , Acidente Vascular Cerebral , Humanos
6.
Int J Obes (Lond) ; 43(9): 1849-1858, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-30464229

RESUMO

BACKGROUND: Changing eating behaviour may be challenging for individuals with obesity and this may be related to attentional bias towards food. Previous paradigms used to assess attentional bias to food stimuli have not distinguished between bottom-up processes related to assessment of rewarding stimuli versus top-down processes related to effects of mind-set on attention. We investigated whether attentional bias for food cues varies between individuals with overweight/obesity and healthy weight individuals, due to differential top-down control of attention. We also determined whether top-down biases predict food consumption in the lab and weight change in our sample over one-year. METHODS: Forty-three participants with overweight/obesity and 49 healthy weight participants between the ages of 18 and 58 participated. Participants completed two attention tasks in a counterbalanced order: (i) a priming task assessing bottom-up control of attention and (ii) a working memory task assessing top-down control of attention. Eating behaviour was assessed by a taste test. At one-year follow-up participants returned to the laboratory to assess changes in their body mass index (BMI). RESULTS: The healthy weight and overweight/obese groups did not differ in demographics and baseline measures (appetite, food liking, taste test food intake). Participants with overweight/obesity showed greater top-down attentional bias towards food cues than did healthy weight participants but had no difference in bottom-up attentional bias. Top down attentional bias towards food cues predicted weight change over one-year but did not predict food intake in the taste test. CONCLUSIONS: The present findings illustrate that the relationship between attentional bias for food, food intake, and body weight is complex. Top-down effects of mind-set on attention, rather than bottom-up control of attention to food may contribute to patterns of eating that result in development and/or maintenance of overweight/obesity. Interventions targeted at top down biases could be effective in facilitating prevention of weight gain.


Assuntos
Atenção/fisiologia , Peso Corporal/fisiologia , Sinais (Psicologia) , Sobrepeso , Adolescente , Adulto , Comportamento Alimentar/fisiologia , Feminino , Seguimentos , Humanos , Masculino , Memória de Curto Prazo/fisiologia , Pessoa de Meia-Idade , Obesidade/fisiopatologia , Obesidade/psicologia , Sobrepeso/fisiopatologia , Sobrepeso/psicologia , Inquéritos e Questionários , Adulto Jovem
7.
Brain Cogn ; 116: 29-39, 2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-28599147

RESUMO

Separate neural systems have been implicated in the recognition of facial identity and emotional expression. A growing number of studies now provide evidence against this modular view by demonstrating that integration of identity and emotion information enhances face processing. Yet, the neural mechanisms that shape this integration remain largely unknown. We hypothesize that the presence of both personal and emotional expression target information triggers changes in functional connectivity between frontal and extrastriate areas in the brain. We report and discuss three important findings. First, the presence of target identity and emotional expression in the same face was associated with super capacity and violations of the independent processing of identity and expression cues. Second, activity in the orbitofrontal cortex (OFC) was associated with the presence of redundant targets and changes in functional connectivity between a particular region of the right OFC (BA11/47) and bilateral visual brain regions (the inferior occipital gyrus (IOG)). Third, these changes in connectivity showed a strong link to behavioural measures of capacity processing. We suggest that the changes in functional connectivity between the right OFC and IOG reduce variability of BOLD responses in the IOG, enhancing integration of identity and emotional expression cues in faces.


Assuntos
Mapeamento Encefálico/métodos , Emoções/fisiologia , Expressão Facial , Reconhecimento Facial/fisiologia , Córtex Pré-Frontal/fisiologia , Adulto , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Córtex Pré-Frontal/diagnóstico por imagem , Adulto Jovem
8.
Brain Cogn ; 105: 22-33, 2016 06.
Artigo em Inglês | MEDLINE | ID: mdl-27045450

RESUMO

The study investigated the processes underlying the retrieval of action information about functional object pairs, focusing on the contribution of procedural and semantic knowledge. We further assessed whether the retrieval of action knowledge is affected by task demands and age. The contribution of procedural knowledge was examined by the way objects were selected, specifically whether active objects were selected before passive objects. The contribution of semantic knowledge was examined by manipulating the relation between targets and distracters. A touchscreen-based search task was used testing young, middle-aged, and elderly participants. Participants had to select by touching two targets among distracters using two search tasks. In an explicit action search task, participants had to select two objects which afforded a mutual action (e.g., functional pair: hammer-nail). Implicit affordance perception was tested using a visual color-matching search task; participants had to select two objects with the same colored frame. In both tasks, half of the colored targets also afforded an action. Overall, middle-aged participants performed better than young and elderly participants, specifically in the action task. Across participants in the action task, accuracy was increased when the distracters were semantically unrelated to the functional pair, while the opposite pattern was observed in the color task. This effect was enhanced with increased age. In the action task all participants utilized procedural knowledge, i.e., selected the active object before the passive object. This result supports the dual-route account from vision to action. Semantic knowledge contributed to both the action and the color task, but procedural knowledge associated with the direct route was primarily retrieved when the task was action-relevant. Across the adulthood lifespan, the data show inverted U-shaped effects of age on the retrieval of action knowledge. Age also linearly increased the involvement of the indirect (semantic) route and the integration of information of the direct and the indirect routes in selection processes.


Assuntos
Atenção/fisiologia , Desenvolvimento Humano/fisiologia , Rememoração Mental/fisiologia , Desempenho Psicomotor/fisiologia , Percepção Espacial/fisiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Conhecimento , Masculino , Pessoa de Meia-Idade , Semântica , Adulto Jovem
9.
Cereb Cortex ; 25(2): 374-83, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23978653

RESUMO

People make faster familiarity decisions for their own face compared with a familiar other. Lesion studies diverge on whether this self-face prioritization (SFP) effect is associated with functional processes isolated in the left or right hemispheres. To assess both decreases (hypo-) and increases (hyper-) in SFP after brain lesion, we asked patients with chronic deficits to perform familiarity judgments to images of their own face, a familiar other, or unfamiliar faces. Of 30 patients, 7 showed hypo- and 6 showed hyper-self-bias effects, comparing responses with their own faces versus responses with a familiar other. Hyper-self-bias correlated with reduced executive control function and, at a neural level, this was associated with lesions to the left prefrontal and superior temporal cortices. In contrast, reduced self-prioritization was associated with damage to the right inferior temporal structures including the hippocampus and extending to the fusiform gyrus. In addition, lesions affecting fibers crossing the right temporal cortex, potentially disconnecting occipital-temporal from frontal regions, diminished the self-bias effect. The data highlight that self-prioritized face processing is linked to regions in the right hemisphere associated with face recognition memory and it also calls on executive processes in the left hemisphere that normally modulate self-prioritized attention.


Assuntos
Encéfalo/fisiologia , Face , Reconhecimento Visual de Modelos/fisiologia , Reconhecimento Psicológico/fisiologia , Autoimagem , Adulto , Idoso , Idoso de 80 Anos ou mais , Encéfalo/patologia , Encéfalo/fisiopatologia , Encefalopatias/patologia , Encefalopatias/fisiopatologia , Mapeamento Encefálico/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos , Estimulação Luminosa , Adulto Jovem
10.
Proc Natl Acad Sci U S A ; 110(19): 7607-12, 2013 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-23610386

RESUMO

Prior social psychological studies show that newly assigned personal significance can modulate high-level cognitive processes, e.g., memory and social evaluation, with self- and other-related information processed in dissociated prefrontal structure: ventral vs. dorsal, respectively. Here, we demonstrate the impact of personal significance on perception and show the neural network that supports this effect. We used an associative learning procedure in which we "tag" a neutral shape with a self-relevant label. Participants were instructed to associate three neutral shapes with labels for themselves, their best friend, or an unfamiliar other. Functional magnetic resonance imaging data were acquired while participants judged whether the shape-label pairs were maintained or swapped. Behaviorally, participants rapidly tagged a neutral stimulus with self-relevance, showing a robust advantage for self-tagged stimuli. Self-tagging responses were associated with enhanced activity in brain regions linked to self-representation [the ventral medial prefrontal cortex (vmPFC)] and to sensory-driven regions associated with social attention [the left posterior superior temporal sulcus (LpSTS)]. In contrast, associations formed with other people recruited a dorsal frontoparietal control network, with the two networks being inversely correlated. Responses in the vmPFC and LpSTS predicted behavioral self-bias effects. Effective connectivity analyses showed that the vmPFC and the LpSTS were functionally coupled, with the strength of coupling associated with behavioral self-biases. The data show that assignment of personal social significance affects perceptual matching by coupling internal self-representations to brain regions modulating attentional responses to external stimuli.


Assuntos
Atenção/fisiologia , Aprendizagem/fisiologia , Comportamento Social , Adolescente , Adulto , Teorema de Bayes , Mapeamento Encefálico/métodos , Cognição , Feminino , Lobo Frontal/fisiologia , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Memória , Modelos Psicológicos , Lobo Parietal/fisiologia , Reprodutibilidade dos Testes , Apoio Social , Adulto Jovem
11.
Exp Brain Res ; 233(8): 2269-81, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25929555

RESUMO

Perception is linked to action via two routes: a direct route based on affordance information in the environment and an indirect route based on semantic knowledge about objects. The present study explored the factors modulating the recruitment of the two routes, in particular which factors affecting the selection of paired objects. In Experiment 1, we presented real objects among semantically related or unrelated distracters. Participants had to select two objects that can interact. The presence of distracters affected selection times, but not the semantic relations of the objects with the distracters. Furthermore, participants first selected the active object (e.g. teaspoon) with their right hand, followed by the passive object (e.g. mug), often with their left hand. In Experiment 2, we presented pictures of the same objects with no hand grip, congruent or incongruent hand grip. Participants had to decide whether the two objects can interact. Action decisions were faster when the presentation of the active object preceded the presentation of the passive object, and when the grip was congruent. Interestingly, participants were slower when the objects were semantically but not functionally related; this effect increased with congruently gripped objects. Our data showed that action decisions in the presence of strong affordance cues (real objects, pictures of congruently gripped objects) relied on sensory-motor representation, supporting the direct route from perception-to-action that bypasses semantic knowledge. However, in the case of weak affordance cues (pictures), semantic information interfered with action decisions, indicating that semantic knowledge impacts action decisions. The data support the dual-route account from perception-to-action.


Assuntos
Atenção/fisiologia , Julgamento/fisiologia , Desempenho Psicomotor/fisiologia , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Reconhecimento Visual de Modelos/fisiologia , Semântica , Adulto Jovem
12.
J Cogn Neurosci ; 26(12): 2701-15, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24893744

RESUMO

Deficits in the ability to draw objects, despite apparently intact perception and motor abilities, are defined as constructional apraxia. Constructional deficits, often diagnosed based on performance on copying complex figures, have been reported in a range of pathologies, perhaps reflecting the contribution of several underlying factors to poor figure drawing. The current study provides a comprehensive analysis of brain-behavior relationships in drawing disorders based on data from a large cohort of subacute stroke patients (n = 358) using whole-brain voxel-wise statistical analyses linked to behavioral measures from a complex figure copy task. We found that (i) overall poor performance on figure copying was associated with subcortical lesions (BG and thalamus), (ii) lateralized deficits with respect to the midline of the viewer were associated with lesions within the posterior parietal lobule, and (iii) spatial positioning errors across the entire figure were associated with lesions within visual processing areas (lingual gyrus and calcarine) and the insula. Furthermore, deficits in reproducing global aspects of form were associated with damage to the right middle temporal gyrus, whereas deficits in representing local features were linked to the left hemisphere lesions within calcarine cortex (extending into the cuneus and precuneus), the insula, and the TPJ. The current study provides strong evidence that impairments in separate cognitive mechanisms (e.g., spatial coding, attention, motor execution, and planning) linked to different brain lesions contribute to poor performance on complex figure copying tasks. The data support the argument that drawing depends on several cognitive processes operating via discrete neuronal networks and that constructional problems as well as hierarchical and spatial representation deficits contribute to poor figure copying.


Assuntos
Mapeamento Encefálico , Córtex Cerebral/fisiologia , Transtornos da Percepção/patologia , Desempenho Psicomotor/fisiologia , Percepção Espacial/fisiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Córtex Cerebral/diagnóstico por imagem , Transtornos Cognitivos/etiologia , Feminino , Lateralidade Funcional/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos , Transtornos da Percepção/complicações , Radiografia , Tomógrafos Computadorizados
13.
Neuroimage ; 89: 289-96, 2014 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-24287439

RESUMO

Recent research indicates that human attention appears inadvertently biased by items that match the contents of working memory (WM). WM-biases can lead to attentional costs when the memory content matches goal-irrelevant items and to attentional benefits when it matches the sought target. Here we used functional and structural MRI data to determine the neural basis of human variation in WM biases. We asked whether human variation in WM-benefits and WM-costs merely reflects the process of attentional capture by the contents of WM or whether variation in WM biases may be associated with distinct forms of cognitive control over internal WM signals based on selection goals. Human ability to use WM contents to facilitate selection was positively correlated with gray matter volume in the left superior posterior parietal cortex (PPC), while the ability to overcome interference by WM-matching distracters was associated with the left inferior PPC in the anterior IPS. Functional activity in the left PPC, measured by functional MRI, also predicted the magnitude of WM-costs on selection. Both structure and function of left PPC mediate the expression of WM biases in human visual attention.


Assuntos
Atenção/fisiologia , Memória de Curto Prazo/fisiologia , Lobo Parietal/fisiologia , Percepção Visual/fisiologia , Adolescente , Adulto , Mapeamento Encefálico , Humanos , Imageamento por Ressonância Magnética , Masculino , Adulto Jovem
14.
Hum Brain Mapp ; 35(8): 3988-4001, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24453176

RESUMO

An fMRI pair-adaptation paradigm was used to identify the brain regions linked to the apprehension of small and large numbers of items. Participants classified stimuli on the basis of their numerosities (fewer or more than five dots). We manipulated the type of repetition within pairs of dot arrays. Overall processing of pairs with small as opposed to large quantities was associated with a decreased BOLD response in the midline structures and inferior parietal cortex. The opposite pattern was observed in middle cingulate cortex. Pairs in which the same numerosity category was repeated, were associated with a decreased signal in the left prefrontal and the left inferior parietal cortices, compared with when numerosities changed. Repetitions of exact numerosities irrespective of sample size were associated with decreased responses in bi-lateral prefrontal, sensory-motor regions, posterior occipital and left intraparietal sulcus (IPS). More importantly, we found value-specific adaptation specific to repeated small quantity in the left lateral occipito-temporal cortex, irrespective of whether the exact same stimulus pattern repeated. Our results indicate that a large network of regions (including the IPS) support visual quantity processing independent of the number of items present; however assimilation of small quantities is associated with additional support from regions within the left occipito-temporal cortex. We propose that processing of small quantities is aided by a subitizing-specific network. This network may account for the increased processing efficiency often reported for numerosities in the subitizing range.


Assuntos
Encéfalo/fisiologia , Conceitos Matemáticos , Pensamento/fisiologia , Percepção Visual/fisiologia , Adulto , Mapeamento Encefálico , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Vias Neurais/fisiologia , Testes Neuropsicológicos , Estimulação Luminosa , Adulto Jovem
15.
PLoS One ; 19(4): e0301098, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38557696

RESUMO

We present Audiovisual Moments in Time (AVMIT), a large-scale dataset of audiovisual action events. In an extensive annotation task 11 participants labelled a subset of 3-second audiovisual videos from the Moments in Time dataset (MIT). For each trial, participants assessed whether the labelled audiovisual action event was present and whether it was the most prominent feature of the video. The dataset includes the annotation of 57,177 audiovisual videos, each independently evaluated by 3 of 11 trained participants. From this initial collection, we created a curated test set of 16 distinct action classes, with 60 videos each (960 videos). We also offer 2 sets of pre-computed audiovisual feature embeddings, using VGGish/YamNet for audio data and VGG16/EfficientNetB0 for visual data, thereby lowering the barrier to entry for audiovisual DNN research. We explored the advantages of AVMIT annotations and feature embeddings to improve performance on audiovisual event recognition. A series of 6 Recurrent Neural Networks (RNNs) were trained on either AVMIT-filtered audiovisual events or modality-agnostic events from MIT, and then tested on our audiovisual test set. In all RNNs, top 1 accuracy was increased by 2.71-5.94% by training exclusively on audiovisual events, even outweighing a three-fold increase in training data. Additionally, we introduce the Supervised Audiovisual Correspondence (SAVC) task whereby a classifier must discern whether audio and visual streams correspond to the same action label. We trained 6 RNNs on the SAVC task, with or without AVMIT-filtering, to explore whether AVMIT is helpful for cross-modal learning. In all RNNs, accuracy improved by 2.09-19.16% with AVMIT-filtered data. We anticipate that the newly annotated AVMIT dataset will serve as a valuable resource for research and comparative experiments involving computational models and human participants, specifically when addressing research questions where audiovisual correspondence is of critical importance.


Assuntos
Aprendizagem , Redes Neurais de Computação , Humanos
16.
Cereb Cortex ; 22(5): 1159-69, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-21775675

RESUMO

Working memory (WM) representations can bias visual selection to matching stimuli in the field. WM biases can, however, be modulated by the level of cognitive load, with WM guidance reduced as memory load increases. Here, we used functional magnetic resonance imaging to distinguish between competing hypotheses for the reduction of WM guidance under load: 1) poor neural representations of memory contents under high load, 2) strategic control at high loads to direct attention away from search distracters matching the WM content, and 3) reduction of frontal top-down biasing of visual areas with increasing memory loads. We show that matching between WM contents and the visual display appeared to be well represented in visual areas under high memory loads, despite a lack of WM guidance at the behavioral level. There was little engagement of "cognitive control" areas in the prefrontal cortex during search at high loads. More importantly, WM guidance at low loads engaged a set of frontal regions in the superior and inferior ventral frontal cortex. Functional connectivity analyses revealed frontal regions working in concert with occipital areas at low memory loads, but this coupling was disrupted by increased memory load. We discuss the implications for understanding the mechanisms supporting the interplay between WM and attention.


Assuntos
Atenção/fisiologia , Mapeamento Encefálico , Memória de Curto Prazo/fisiologia , Córtex Pré-Frontal/fisiologia , Percepção Visual/fisiologia , Adulto , Feminino , Humanos , Interpretação de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Masculino , Adulto Jovem
17.
J Cogn Neurosci ; 24(4): 948-64, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22220729

RESUMO

This study is the first to assess lesion-symptom relations for subitizing and counting impairments in a large sample of neuropsychological patients (41 patients) using an observer-independent voxel-based approach. We tested for differential effects of enumerating small versus large numbers of items while controlling for hemianopia and visual attention deficits. Overall impairments in the enumeration of any numbers (small or large) were associated with an extended network, including bilateral occipital and fronto-parietal regions. Within this network, severe impairments in accuracy when enumerating small sets of items (in the subitizing range) were associated with damage to the left posterior occipital cortex, bilateral lateral occipital and right superior frontal cortices. Lesions to the right calcarine extending to the precuneus led to patients serially counting even small numbers of items (indicated by a steep response slope), again demonstrating an impaired subitizing ability. In contrast, impairments in counting large numerosities were associated with damage to the left intraparietal sulcus. The data support the argument for some distinctive processes and neural areas necessary to support subitization and counting with subitizing relying on processes of posterior occipital cortex and with counting associated with processing in the parietal cortex.


Assuntos
Mapeamento Encefálico , Encéfalo/patologia , Transtornos Cognitivos/patologia , Matemática , Reconhecimento Visual de Modelos/fisiologia , Resolução de Problemas/fisiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Lesões Encefálicas/complicações , Transtornos Cognitivos/etiologia , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Estimulação Luminosa , Tempo de Reação/fisiologia , Estatística como Assunto , Vias Visuais/patologia
18.
J Cogn Neurosci ; 24(11): 2268-79, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22905819

RESUMO

There is considerable evidence that there are anatomically and functionally distinct pathways for action and object recognition. However, little is known about how information about action and objects is integrated. This study provides fMRI evidence for task-based selection of brain regions associated with action and object processing, and on how the congruency between the action and the object modulates neural response. Participants viewed videos of objects used in congruent or incongruent actions and attended either to the action or the object in a one-back procedure. Attending to the action led to increased responses in a fronto-parietal action-associated network. Attending to the object activated regions within a fronto-inferior temporal network. Stronger responses for congruent action-object clips occurred in bilateral parietal, inferior temporal, and putamen. Distinct cortical and thalamic regions were modulated by congruency in the different tasks. The results suggest that (i) selective attention to action and object information is mediated through separate networks, (ii) object-action congruency evokes responses in action planning regions, and (iii) the selective activation of nuclei within the thalamus provides a mechanism to integrate task goals in relation to the congruency of the perceptual information presented to the observer.


Assuntos
Imageamento por Ressonância Magnética/métodos , Movimento/fisiologia , Rede Nervosa/fisiologia , Estimulação Luminosa/métodos , Desempenho Psicomotor/fisiologia , Percepção Visual/fisiologia , Adolescente , Adulto , Mapeamento Encefálico/métodos , Feminino , Lobo Frontal/fisiologia , Humanos , Masculino , Percepção de Movimento/fisiologia , Lobo Parietal/fisiologia , Lobo Temporal/fisiologia , Adulto Jovem
19.
J Cogn Neurosci ; 24(3): 718-35, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22066584

RESUMO

Because of our limited processing capacity, different elements of the visual scene compete for the allocation of processing resources. One of the most striking deficits in visual selection is simultanagnosia, a rare neuropsychological condition characterized by impaired spatial awareness of more than one object at time. To decompose the neuroanatomical substrates of the syndrome and to gain insights into the structural and functional organization of visuospatial attention, we performed a systematic evaluation of lesion patterns in a group of simultanagnosic patients compared with patients with either (i) unilateral visuospatial deficits (neglect and/or extinction) or (ii) bilateral posterior lesions without visuospatial deficits, using overlap/subtraction analyses, estimation of lesion volume, and a lesion laterality index. We next used voxel-based morphometry to assess the link between different visuospatial deficits and gray matter and white matter (WM) damage. Lesion overlap/subtraction analyses, lesion laterality index, and voxel-based morphometry measures converged to indicate that bilateral parieto-occipital WM disconnections are both distinctive and necessary to create symptoms associated with simultanagnosia. We also found that bilateral gray matter damage within the middle frontal area (BA 46), cuneus, calacarine, and parieto-occipital fissure as well as right hemisphere parietal lesions within intraparietal and postcentral gyri were associated with simultanagnosia. Further analysis of the WM based on tractography revealed associations with bilateral damage to major pathways within the visuospatial attention network, including the superior longitudinal fasciculus, the inferior fronto-occipital fasciculus, and the inferior longitudinal fasciculus. We conclude that damage to the parieto-occipital regions and the intraparietal sulcus, together, with bilateral WM disconnections within the visuosptial attention network, contribute to poor visual processing of multiple objects and the loss of processing speed characteristic of simultanagnosia.


Assuntos
Atenção/fisiologia , Mapeamento Encefálico , Lateralidade Funcional/fisiologia , Transtornos da Percepção/patologia , Percepção Espacial/fisiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Imagem de Difusão por Ressonância Magnética , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos , Índice de Gravidade de Doença , Adulto Jovem
20.
Hum Brain Mapp ; 33(1): 105-20, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21425391

RESUMO

Recent research indicates that working memory (WM) and attention interact, with attention automatically biased to stimuli that match the contents of WM. Though there is behavioral evidence for verbal guidance (written words) as well as guidance by more visual cues in WM, we have limited understanding of how these two representational formats influence the guidance of visual selection at a neural level. Here, we present converging evidence from functional MRI and transcranial magnetic stimulation (TMS), which indicates that both common and distinct neural regions mediate the influence of visuoverbal representations on WM. Colored shapes, but not words, in WM activated the superior frontal gyrus (SFG) and recognition memory areas in the temporal lobe when the contents of WM matched a stimulus in a subsequent search display. rTMS to the SFG disrupted WM effects from colored shapes. The lateral occipital cortex, however, tended to be more activated with written word cues, and rTMS to the lateral occipital complex tended to disrupt effects from written words more than from colored shapes in WM. There was also evidence for cue validity effects from colored shapes and written stimuli operating through different subthalamic nuclei. We discuss the evidence for understanding the neural systems mediating attention effects from WM.


Assuntos
Atenção/fisiologia , Encéfalo/fisiologia , Memória de Curto Prazo/fisiologia , Visão Ocular/fisiologia , Adulto , Sinais (Psicologia) , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Estimulação Luminosa , Estimulação Magnética Transcraniana
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