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1.
J Exp Child Psychol ; 239: 105810, 2024 03.
Artigo em Inglês | MEDLINE | ID: mdl-37981466

RESUMO

Altruistic behavior, which intentionally benefits a recipient without expectation of a reward or at a cost to the actor, is observed throughout the lifespan from everyday interactions to emergency situations. Empathy has long been considered a major driver of altruistic action, but the social information processing model supports the idea that other cognitive processes may also play a role in altruistic intention and behavior. Our aim was to investigate how visual analysis, attention, inhibitory control, and theory of mind capabilities uniquely contribute to predicting altruistic intention and behavior in a sample of 67 French children (35 girls and 32 boys; Mage = 9.92 ± 0.99 years) from Paris and neighboring suburbs. Using a Bayesian analysis framework, we showed that in younger grade levels visual analysis and selective attention are strong predictors of altruistic intention and that inhibitory control strongly predicts altruistic behavior in a dictator game. Processes underlying theory of mind, however, negatively predict altruistic behavior in the youngest grade. In higher grade levels, we found that stronger attention and inhibitory control predicts lower altruistic intention and behavior. Empathy was not found to predict altruistic intention or behavior. These results suggest that different cognitive capabilities are involved in altruistic intention and behavior and that their contribution changes throughout middle childhood as social constraints deepen and altruism calls on more complex reasoning.


Assuntos
Altruísmo , Empatia , Masculino , Feminino , Humanos , Criança , Teorema de Bayes , Intenção , Cognição
2.
J Neural Transm (Vienna) ; 130(3): 409-424, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36547695

RESUMO

Vision has a crucial role to play in human development and functioning. It is, therefore, not surprising that vision plays a fundamental role in the development of the child. As a consequence, an alteration in visual function is, therefore, likely to hinder the child's development. Although ocular disorders are well known, diagnosed and taken into account, cerebral visual impairments (CVI) resulting from post-chiasmatic damage are largely underdiagnosed. However, among the disorders resulting from an episode of perinatal asphyxia and/or associated with prematurity, or neonatal hypoglycaemia, CVIs are prominent. In this article, we focus on the role of the possible effects of CVI on a child's learning abilities, leading to major difficulty in disentangling the consequences of CVI from other neurodevelopmental disorders (NDD) such as dyslexia, dyscalculia, dysgraphia, attention-deficit/hyperactivity disorder (ADHD), developmental coordination disorder (DCD) and autism spectrum disorders (ASD). Although we focus here on the possible overlap between children with CVI and children with other NDD, De Witt et al. (Wit et al. Ear Hear 39:1-19, 2018) have raised exactly the same question regarding children with auditory processing disorders (the equivalent of CVI in the auditory modality). We underline how motor, social and cognitive development as well as academic success can be impaired by CVI and raise the question of the need for systematic evaluation for disorders of vision, visual perception and cognition in all children presenting with a NDD and/or previously born under adverse neurological conditions.


Assuntos
Transtornos de Deficit da Atenção e do Comportamento Disruptivo , Desenvolvimento Infantil , Deficiências da Aprendizagem , Transtornos da Visão , Córtex Visual , Percepção Visual , Visão Ocular , Cognição , Humanos , Criança , Transtornos da Visão/complicações , Transtornos da Visão/congênito , Deficiências da Aprendizagem/etiologia , Transtornos de Deficit da Atenção e do Comportamento Disruptivo/etiologia , Córtex Visual/anormalidades
3.
Brain Cogn ; 155: 105811, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34737127

RESUMO

Coarse information of a visual stimulus is conveyed by Low Spatial Frequencies (LSF) and is thought to be rapidly extracted to generate predictions. This may guide fast recognition with the subsequent integration of fine information, conveyed by High Spatial Frequencies (HSF). In autism, emotional face recognition is challenging, and might be related to alterations in LSF predictive processes. We analyzed the data of 27 autistic and 34 non autistic (NA) adults on an emotional Stroop task (i.e., emotional face with congruent or incongruent emotional word) with spatially filtered primes (HSF vs.LSF). We hypothesized that LSF primes would generate predictions leading to faster categorization of the target face compared to HSF primes, in the NA group but not in autism. Surprisingly, HSF primes led to faster categorization than LSF primes in both groups. Moreover, the advantage of HSF vs.LSF primes was stronger for angry than happy faces in NA, but was stronger for happy than angry faces in autistic participants. Drift diffusion modelling confirmed HSF advantage and showed a longer non-decision time (e.g., encoding) in autism. Despite LSF predictive impairments in autism was not corroborated, our analyses suggest low level processing specificities in autism.


Assuntos
Transtorno Autístico , Reconhecimento Facial , Adulto , Emoções , Felicidade , Humanos , Reconhecimento Visual de Modelos , Estimulação Luminosa , Reconhecimento Psicológico
4.
Int J Mol Sci ; 22(3)2021 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-33540815

RESUMO

The role of melatonin has been extensively investigated in pathophysiological conditions, including autism spectrum disorder (ASD). Reduced melatonin secretion has been reported in ASD and led to many clinical trials using immediate-release and prolonged-release oral formulations of melatonin. However, melatonin's effects in ASD and the choice of formulation type require further study. Therapeutic benefits of melatonin on sleep disorders in ASD were observed, notably on sleep latency and sleep quality. Importantly, melatonin may also have a role in improving autistic behavioral impairments. The objective of this article is to review factors influencing treatment response and possible side effects following melatonin administration. It appears that the effects of exposure to exogenous melatonin are dependent on age, sex, route and time of administration, formulation type, dose, and association with several substances (such as tobacco or contraceptive pills). In addition, no major melatonin-related adverse effect was described in typical development and ASD. In conclusion, melatonin represents currently a well-validated and tolerated treatment for sleep disorders in children and adolescents with ASD. A more thorough consideration of factors influencing melatonin pharmacokinetics could illuminate the best use of melatonin in this population. Future studies are required in ASD to explore further dose-effect relationships of melatonin on sleep problems and autistic behavioral impairments.


Assuntos
Transtorno do Espectro Autista/complicações , Melatonina/farmacocinética , Transtornos Intrínsecos do Sono/tratamento farmacológico , Administração Oral , Adulto , Transtorno do Espectro Autista/metabolismo , Transtorno do Espectro Autista/psicologia , Disponibilidade Biológica , Criança , Pré-Escolar , Ritmo Circadiano , Preparações de Ação Retardada , Suplementos Nutricionais , Feminino , Humanos , Injeções Intravenosas , Masculino , Melatonina/administração & dosagem , Melatonina/análogos & derivados , Melatonina/fisiologia , Melatonina/uso terapêutico , Melatonina/urina , Receptores de Melatonina/fisiologia , Saliva/química , Estações do Ano , Serotonina/metabolismo , Transtornos Intrínsecos do Sono/etiologia , Transtornos Intrínsecos do Sono/fisiopatologia , Latência do Sono/efeitos dos fármacos , Transtornos do Comportamento Social/tratamento farmacológico , Transtornos do Comportamento Social/etiologia , Triptofano/metabolismo
5.
BMC Neurol ; 19(1): 270, 2019 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-31684891

RESUMO

BACKGROUND: In the nineteenth century, Jean Martin Charcot explained functional neurological disorder (formerly called conversion disorder) as a "psychodynamic" lesion. Numerous advances in neuroimaging have permitted identification of the neural underpinnings of this disorder. CASE PRESENTATION: Herein we describe a case of functional neurological disorder (FND) with initial left sensorimotor deficit, in-coordinated limb movements, neglect, clouded consciousness, slurred speech and a semiology of visual impairment. A single photon emission computed tomography (SPECT) showed a right thalamic hypoperfusion, which is rather concordant with the initial semiology. Later, the semiology changed, presenting with a predominantly neurovisual complex presentation. The second SPECT showed no more thalamic abnormalities but an hypoperfusion in the right temporo-occipital junction, right inferior parietal lobe and left superior frontal lobe, which is also rather concordant with the changing semiology. CONCLUSIONS: This case illustrates the evolving neuroimaging patterns of FND but also the concordance between semiology and neuroimaging findings in FND supporting Charcot's theory of "dynamic lesion".


Assuntos
Encéfalo , Transtorno Conversivo , Neuroimagem , Tomografia Computadorizada de Emissão de Fóton Único , Encéfalo/diagnóstico por imagem , Encéfalo/fisiopatologia , Transtorno Conversivo/diagnóstico por imagem , Transtorno Conversivo/fisiopatologia , Humanos
6.
Vis Neurosci ; 35: E006, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-29905126

RESUMO

In age-related macular degeneration (AMD), the processing of fine details in a visual scene, based on a high spatial frequency processing, is impaired, while the processing of global shapes, based on a low spatial frequency processing, is relatively well preserved. The present fMRI study aimed to investigate the residual abilities and functional brain changes of spatial frequency processing in visual scenes in AMD patients. AMD patients and normally sighted elderly participants performed a categorization task using large black and white photographs of scenes (indoors vs. outdoors) filtered in low and high spatial frequencies, and nonfiltered. The study also explored the effect of luminance contrast on the processing of high spatial frequencies. The contrast across scenes was either unmodified or equalized using a root-mean-square contrast normalization in order to increase contrast in high-pass filtered scenes. Performance was lower for high-pass filtered scenes than for low-pass and nonfiltered scenes, for both AMD patients and controls. The deficit for processing high spatial frequencies was more pronounced in AMD patients than in controls and was associated with lower activity for patients than controls not only in the occipital areas dedicated to central and peripheral visual fields but also in a distant cerebral region specialized for scene perception, the parahippocampal place area. Increasing the contrast improved the processing of high spatial frequency content and spurred activation of the occipital cortex for AMD patients. These findings may lead to new perspectives for rehabilitation procedures for AMD patients.


Assuntos
Lobo Occipital/fisiologia , Processamento Espacial/fisiologia , Percepção Visual/fisiologia , Degeneração Macular Exsudativa/metabolismo , Idoso , Mapeamento Encefálico , Exsudatos e Transudatos , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Tomografia de Coerência Óptica , Campos Visuais , Degeneração Macular Exsudativa/diagnóstico por imagem
7.
Exp Brain Res ; 232(3): 903-17, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24366440

RESUMO

In order to further our understanding of action-blindsight, four hemianopic patients suffering from visual field loss contralateral to a unilateral occipital lesion were compared to six healthy controls during a double task of verbally reported target detection and saccadic responses toward the target. Three oculomotor tasks were used: a fixation task (i.e., without saccade) and two saccade tasks (eliciting reflexive and voluntary saccades, using step and overlap 600 ms paradigms, respectively), in separate sessions. The visual target was briefly presented at two different eccentricities (5° and 8°), in the right or left visual hemifield. Blank trials were interleaved with target trials, and signal detection theory was applied. Despite their hemifield defect, hemianopic patients retained the ability to direct a saccade toward their contralesional hemifield, whereas verbal detection reports were at chance level. However, saccade parameters (latency and amplitude) were altered by the defect. Saccades to the contralesional hemifield exhibited longer latencies and shorter amplitudes compared to those of the healthy group, whereas only the latencies of reflexive saccades to the ipsilesional hemifield were altered. Furthermore, healthy participants showed the expected latency difference between reflexive and voluntary saccades, with the latter longer than the former. This difference was not found in three out of four patients in either hemifield. Our results show action-blindsight for saccades, but also show that unilateral occipital lesions have effects on saccade generation in both visual hemifields.


Assuntos
Lateralidade Funcional/fisiologia , Hemianopsia/complicações , Transtornos da Motilidade Ocular/etiologia , Movimentos Sacádicos/fisiologia , Adulto , Idoso , Análise de Variância , Córtex Cerebral/patologia , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Estimulação Luminosa , Tempo de Reação/fisiologia , Testes de Campo Visual
8.
Front Neurosci ; 18: 1373377, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38784094

RESUMO

This short review examines recent advancements in neurotechnologies within the context of managing unilateral spatial neglect (USN), a common condition following stroke. Despite the success of brain-computer interfaces (BCIs) in restoring motor function, there is a notable absence of effective BCI devices for treating cerebral visual impairments, a prevalent consequence of brain lesions that significantly hinders rehabilitation. This review analyzes current non-invasive BCIs and technological solutions dedicated to cognitive rehabilitation, with a focus on visuo-attentional disorders. We emphasize the need for further research into the use of BCIs for managing cognitive impairments and propose a new potential solution for USN rehabilitation, by combining the clinical subtleties of this syndrome with the technological advancements made in the field of neurotechnologies.

9.
Ann Clin Transl Neurol ; 11(5): 1365-1370, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38509632

RESUMO

OBJECTIVE: According to a seminal hypothesis stated by Crick and Koch in 1995, one is not aware of neural activity in primary visual cortex (V1) because this region lacks reciprocal connections with prefrontal cortex (PFC). METHODS: We provide here a neuropsychological illustration of this hypothesis in a patient with a very rare form of cortical blindness: ventral and dorsal cortical pathways were lesioned bilaterally while V1 areas were partially preserved. RESULTS: Visual stimuli escaped conscious perception but still activated V1 regions that were functionally disconnected from PFC. INTERPRETATION: These results are consistent with the hypothesis of a causal role of PFC in visual awareness.


Assuntos
Córtex Visual Primário , Humanos , Córtex Visual Primário/fisiologia , Córtex Visual Primário/fisiopatologia , Cegueira Cortical/fisiopatologia , Masculino , Conscientização/fisiologia , Percepção Visual/fisiologia , Córtex Pré-Frontal/fisiopatologia , Córtex Pré-Frontal/fisiologia , Testes Neuropsicológicos , Feminino , Adulto , Imageamento por Ressonância Magnética
10.
J Cogn Neurosci ; 25(8): 1315-31, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23574583

RESUMO

Using large natural scenes filtered in spatial frequencies, we aimed to demonstrate that spatial frequency processing could not only be retinotopically mapped but could also be lateralized in both hemispheres. For this purpose, participants performed a categorization task using large black and white photographs of natural scenes (indoors vs. outdoors, with a visual angle of 24° × 18°) filtered in low spatial frequencies (LSF), high spatial frequencies (HSF), and nonfiltered scenes, in block-designed fMRI recording sessions. At the group level, the comparison between the spatial frequency content of scenes revealed first that, compared with HSF, LSF scene categorization elicited activation in the anterior half of the calcarine fissures linked to the peripheral visual field, whereas, compared with LSF, HSF scene categorization elicited activation in the posterior part of the occipital lobes, which are linked to the fovea, according to the retinotopic property of visual areas. At the individual level, functional activations projected on retinotopic maps revealed that LSF processing was mapped in the anterior part of V1, whereas HSF processing was mapped in the posterior and ventral part of V2, V3, and V4. Moreover, at the group level, direct interhemispheric comparisons performed on the same fMRI data highlighted a right-sided occipito-temporal predominance for LSF processing and a left-sided temporal cortex predominance for HSF processing, in accordance with hemispheric specialization theories. By using suitable method of analysis on the same data, our results enabled us to demonstrate for the first time that spatial frequencies processing is mapped retinotopically and lateralized in human occipital cortex.


Assuntos
Mapeamento Encefálico , Lateralidade Funcional/fisiologia , Reconhecimento Visual de Modelos/fisiologia , Percepção Espacial/fisiologia , Córtex Visual/fisiologia , Campos Visuais/fisiologia , Adulto , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Masculino , Oxigênio , Estimulação Luminosa , Tempo de Reação , Reconhecimento Psicológico , Córtex Visual/irrigação sanguínea , Vias Visuais/irrigação sanguínea , Vias Visuais/fisiologia , Adulto Jovem
11.
Ann Neurol ; 71(4): 531-8, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22447670

RESUMO

OBJECTIVE: Visual Evoked Potentials (VEPs) following optic neuritis (ON) remain chronically prolonged, although standard visual tests indicate full recovery. We hypothesized that dynamic visual processes, such as motion perception, may be more vulnerable to slowed conduction in the optic nerve, and consequently be better associated with projection rates. METHODS: Twenty-one patients with acute unilateral, first-ever ON were studied during 1 year. Static visual functions (visual acuity, color perception, visual field, and contrast sensitivity), dynamic visual functions (motion perception), and VEPs were assessed repeatedly. RESULTS: Visual and electrophysiological measurements reached maximal performance 4 months following the acute phase, with no subsequent improvement. Whereas VEP amplitude and static visual functions recovered, VEP latency remained significantly prolonged, and motion perception remained impaired throughout the 12-month period. A strong correlation was found between VEP latencies and motion perception. Visual performance at 1 month was strongly predictive of visual outcome. For static functions, patients who showed partial recovery at 1 month subsequently achieved full recovery. For dynamic functions, the rate of improvement was constant across patients, independent of the initial deficit level. INTERPRETATION: Conduction velocity in the visual pathways correlated closely with dynamic visual functions, implicating the need for rapid transmission of visual input to perceive motion. Motion perception level may serve as a tool to assess the magnitude of myelination in the visual pathways. The constancy across patients may serve as a baseline to assess the efficacy of currently developing neuroprotective and regenerative therapeutic strategies, targeting myelination in the central nervous system.


Assuntos
Doenças Desmielinizantes/complicações , Percepção de Movimento/fisiologia , Neurite Óptica/complicações , Recuperação de Função Fisiológica , Adolescente , Adulto , Potenciais Evocados Visuais/fisiologia , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem
12.
Brain Topogr ; 26(2): 264-77, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22878845

RESUMO

The current study aims to investigate visual scene perception and its neuro-anatomical correlates for stimuli presented in the central visual field of patients with homonymous hemianopia, and thereby to assess the effect of a right or a left occipital lesion on brain reorganization. Fourteen healthy participants, three left brain damaged (LBD) patients with right homonymous hemianopia and five right brain damaged (RBD) patients with left homonymous hemianopia performed a visual detection task (i.e. "Is there an image on the screen?") and a categorization task (i.e. "Is it an image of a highway or a city?") during a block-designed functional magnetic resonance imaging recording session. Cerebral activity analyses of the posterior areas-the occipital lobe in particular-highlighted bi-hemispheric activation during the detection task but more lateralized, left occipital lobe activation during the categorization task in healthy participants. Conversely, in patients, the same network of activity was observed in both tasks. However, LBD patients showed a predominant activation in their right hemisphere (occipital lobe and posterior temporal areas) whereas RBD patients showed a more bilateral activation (in the occipital lobes). Overall, our preliminary findings suggest a specific pattern of cerebral activation depending on the task instruction in healthy participants and cerebral reorganization of the posterior areas following brain injury in hemianopic patients which could depend upon the side of the occipital lesion.


Assuntos
Córtex Cerebral/patologia , Córtex Cerebral/fisiologia , Hemianopsia/patologia , Hemianopsia/fisiopatologia , Imageamento por Ressonância Magnética , Visão Ocular/fisiologia , Campos Visuais/fisiologia , Adulto , Idoso , Isquemia Encefálica/complicações , Mapeamento Encefálico , Estudos de Casos e Controles , Hemorragia Cerebral/complicações , Lateralidade Funcional/fisiologia , Hemianopsia/etiologia , Humanos , Masculino , Pessoa de Meia-Idade , Lobo Occipital/anatomia & histologia , Lobo Occipital/fisiologia , Percepção Visual/fisiologia
13.
Antioxidants (Basel) ; 12(11)2023 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-38001870

RESUMO

The article presents a review of the relationships between melatonin and neurodevelopmental disorders. First, the antioxidant properties of melatonin and its physiological effects are considered to understand better the role of melatonin in typical and atypical neurodevelopment. Then, several neurodevelopmental disorders occurring during infancy, such as autism spectrum disorder or neurogenetic disorders associated with autism (including Smith-Magenis syndrome, Angelman syndrome, Rett's syndrome, Tuberous sclerosis, or Williams-Beuren syndrome) and neurodevelopmental disorders occurring later in adulthood like bipolar disorder and schizophrenia, are discussed with regard to impaired melatonin production and circadian rhythms, in particular, sleep-wake rhythms. This article addresses the issue of overlapping symptoms that are commonly observed within these different mental conditions and debates the role of abnormal melatonin production and altered circadian rhythms in the pathophysiology and behavioral expression of these neurodevelopmental disorders.

14.
Semin Pediatr Neurol ; 47: 101070, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37919040

RESUMO

PROFILING CHILDREN WITH CEREBRAL VISUAL IMPAIRMENT USING MULTIPLE METHODS OF ASSESSMENT TO AID IN DIFFERENTIAL DIAGNOSIS: Amanda H. Lueck , Gordon N. Dutton , Sylvie Chokron Seminars in Pediatric Neurology Volume 31, October 2019, Pages 5-14 Cerebral (cortical) visual impairment (CVI), the primary cause of visual impairment in chil dren in high-income countries, is increasing globally due to improved life-saving measures for premature and full-term infants. Yet the consequences of this condition are only begin ning to be understood and addressed. According to the topography, site, and the extent of the pathology, the deficit may variably concern central visual functions, visual field, percep tion of movement, visual analysis, visual exploration, attention, or visual memory, as well as visual guidance of movement. Each affected child has a unique clinical picture, which needs to be identified and individually profiled. This is probably the underlying reason that CVI is commonly underdiagnosed or misdiagnosed, especially in children, and, as a consequence, the full range of potential behavioral outcomes are not identified and adequately addressed. The present paper shows how the use of multiple methods of assessment can improve understanding of children with CVI.


Assuntos
Encefalopatias , Neurologia , Baixa Visão , Lactente , Criança , Humanos , Diagnóstico Diferencial , Encefalopatias/diagnóstico , Transtornos da Visão/diagnóstico , Baixa Visão/diagnóstico
15.
Neurosci Conscious ; 2022(1): niab043, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35237447

RESUMO

Blindsight regroups the different manifestations of preserved discriminatory visual capacities following the damage to the primary visual cortex. Blindsight types differentially impact objective and subjective perception, patients can report having no visual awareness whilst their behaviour suggests visual processing still occurs at some cortical level. This phenomenon hence presents a unique opportunity to study consciousness and perceptual consciousness, and for this reason, it has had an historical importance for the development of this field of research. From these studies, two main opposing models of the underlying mechanisms have been established: (a) blindsight is perception without consciousness or (b) blindsight is in fact degraded vision, two views that mirror more general theoretical options about whether unconscious cognition truly exists or whether it is only a degraded form of conscious processing. In this article, we want to re-examine this debate in the light of recent advances in the characterization of blindsight and associated phenomena. We first provide an in-depth definition of blindsight and its subtypes, mainly blindsight type I, blindsight type II and the more recently described blindsense. We emphasize the necessity of sensitive and robust methodology to uncover the dissociations between perception and awareness that can be observed in brain-damaged patients with visual field defects at different cognitive levels. We discuss these different profiles of dissociation in the light of both contending models. We propose that the different types of dissociations reveal a pattern of relationship between perception, awareness and metacognition that is actually richer than what is proposed by either of the existing models. Finally, we consider this in the framework of current theories of consciousness and touch on the implications the findings of blindsight have on these.

16.
Vis Neurosci ; 28(6): 529-41, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22192508

RESUMO

Age-related macular degeneration (AMD) is characterized by a central vision loss. We explored the relationship between the retinal lesions in AMD patients and the processing of spatial frequencies in natural scene categorization. Since the lesion on the retina is central, we expected preservation of low spatial frequency (LSF) processing and the impairment of high spatial frequency (HSF) processing. We conducted two experiments that differed in the set of scene stimuli used and their exposure duration. Twelve AMD patients and 12 healthy age-matched participants in Experiment 1 and 10 different AMD patients and 10 healthy age-matched participants in Experiment 2 performed categorization tasks of natural scenes (Indoors vs. Outdoors) filtered in LSF and HSF. Experiment 1 revealed that AMD patients made more no-responses to categorize HSF than LSF scenes, irrespective of the scene category. In addition, AMD patients had longer reaction times to categorize HSF than LSF scenes only for indoors. Healthy participants' performance was not differentially affected by spatial frequency content of the scenes. In Experiment 2, AMD patients demonstrated the same pattern of errors as in Experiment 1. Furthermore, AMD patients had longer reaction times to categorize HSF than LSF scenes, irrespective of the scene category. Again, spatial frequency processing was equivalent for healthy participants. The present findings point to a specific deficit in the processing of HSF information contained in photographs of natural scenes in AMD patients. The processing of LSF information is relatively preserved. Moreover, the fact that the deficit is more important when categorizing HSF indoors, may lead to new perspectives for rehabilitation procedures in AMD.


Assuntos
Degeneração Macular/fisiopatologia , Reconhecimento Visual de Modelos/fisiologia , Reconhecimento Psicológico/fisiologia , Percepção Espacial/fisiologia , Idoso , Idoso de 80 Anos ou mais , Análise de Variância , Estudos de Casos e Controles , Feminino , Humanos , Masculino , Testes Neuropsicológicos , Estimulação Luminosa , Tempo de Reação/fisiologia
17.
Graefes Arch Clin Exp Ophthalmol ; 249(2): 223-32, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-20652817

RESUMO

BACKGROUND: Bottom-up and top-down processes are involved in visual analysis of scenes. Here we examined the influence of top-down visual demand on natural scene processing. METHODS: We measured accuracy and response time in adults performing two stimuli-equivalent tasks. Unfiltered, low or high spatial frequency (SF) natural scenes were presented in central, left, or right visual fields (CVF, LVF, RVF). The tasks differed only by the instructed visual demand. In the detection task, participants had to decide whether a scene was present or not. In the categorization task, they had to decide whether the scene was a city or a forest. RESULTS: Higher accuracy was seen for the LVF in the detection task, but for categorization, greater accuracy was seen for the RVF. The interaction between Task and SF revealed coarse-to-fine processing in the categorization task for both accuracy and reaction time, which nearly disappeared in the detection task. Considering the interaction of Task, VF and SF, a left-hemisphere specialisation (i.e., RVF advantage) was observed for the categorisation of HSF scenes for accuracy alone, whereas a LVF advantage was seen for all SFs in the detection task for both accuracy and reaction time. CONCLUSION: Our results revealed that the nature of top-down visual demand is essential to understanding how visual analysis is achieved in each hemisphere. Moreover, this study examining the effects of visual demand, visual field presentation, and SF content of stimuli through the use of ecological stimuli provides a tool to enrich the clinical examination of visual and neurovisual patients.


Assuntos
Campos Visuais/fisiologia , Percepção Visual/fisiologia , Adulto , Idoso , Feminino , Percepção de Forma/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Análise e Desempenho de Tarefas , Fatores de Tempo , Córtex Visual/fisiologia , Adulto Jovem
18.
Front Hum Neurosci ; 15: 713316, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34720906

RESUMO

Medical advances in neonatology have improved the survival rate of premature infants, as well as children who are born under difficult neurological conditions. As a result, the prevalence of cerebral dysfunctions, whether minimal or more severe, is increasing in all industrialized countries and in some developing nations. Whereas in the past, ophthalmological diseases were considered principally responsible for severe visual impairment, today, all recent epidemiological studies show that the primary cause of blindness and severe visual impairment in children in industrialized countries is now neurological, with lesions acquired around the time of birth currently comprising the commonest contributor. The resulting cortical or cerebral visual impairments (CVIs) have long been ignored, or have been confused either with other ophthalmological disorders causing low vision, or with a range of learning disabilities. We present here the deleterious consequences that CVI can have upon learning and social interaction, and how these can be given behavioral labels without the underlying visual causes being considered. We discuss the need to train and inform clinicians in the identification and diagnosis of CVI, and how to distinguish the diagnosis of CVI from amongst other visual disorders, including the specific learning disorders. This is important because the range of approaches needed to enhance the development of children with CVI is specific to each child's unique visual needs, making incorrect labeling or diagnosis potentially detrimental to affected children because these needs are not met.

19.
Front Hum Neurosci ; 15: 732764, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34776904

RESUMO

Recent years have been marked by the fulgurant expansion of non-invasive Brain-Computer Interface (BCI) devices and applications in various contexts (medical, industrial etc.). This technology allows agents "to directly act with thoughts," bypassing the peripheral motor system. Interestingly, it is worth noting that typical non-invasive BCI paradigms remain distant from neuroscientific models of human voluntary action. Notably, bidirectional links between action and perception are constantly ignored in BCI experiments. In the current perspective article, we proposed an innovative BCI paradigm that is directly inspired by the ideomotor principle, which postulates that voluntary actions are driven by the anticipated representation of forthcoming perceptual effects. We believe that (1) adapting BCI paradigms could allow simple action-effect bindings and consequently action-effect predictions and (2) using neural underpinnings of those action-effect predictions as features of interest in AI methods, could lead to more accurate and naturalistic BCI-mediated actions.

20.
Autism Res ; 14(11): 2393-2404, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34223712

RESUMO

Research suggested the possibility that temporal cognition may be different in autistic spectrum disorder (ASD). Although there are some empirical studies examining timing ability in these individuals, to our knowledge, no one directly assessed the ability to predict when an event will occur. Here, we report a study on implicit temporal preparation in individuals with ASD as indexed by the variable foreperiod (FP) effect. We compared a group of adult ASD participants to a group of typically-developed (TD) controls, for their respective abilities to utilize implicit temporal information in a simple detection task with three different preparatory intervals (FP, short, middle and long). Participants were given a warning tone to signal an imminent stimulus, and asked to press a key as quickly as they could upon detection of the stimulus. Both groups were able to use implicit temporal information, as revealed by both the variable-FP effect (i.e., faster response for targets appearing after a long FP) and asymmetric sequential effects (i.e., slower response in short-FP trials following a previous long-FP trial). The TD group exhibited a faster response in a long-FP trial that was preceded by short-FP one, whereas the ASD group did not, as reflected in their higher percentage of response omissions for a target that appeared later than in the previous trial. The reduced ability of ASD participants to modulate their responses under these conditions might reflect a difficulty in time-based monitoring of stimulus occurrence. LAY SUMMARY: Time-processing may be different in autistic spectrum disorder (ASD). This study addressed the ability to anticipate a relevant stimulus's onset according to predictable interstimulus intervals comparing adults with ASD and typically developed controls. We found that ASD participants did not benefit from temporal preparation when stimulus appeared later than previously attended. This suggests a reduced ability in detecting implicit temporal regularities between events.


Assuntos
Transtorno do Espectro Autista , Percepção do Tempo , Adulto , Atenção , Cognição , Humanos , Tempo de Reação
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