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1.
Brain Res ; 1722: 146343, 2019 11 01.
Article in English | MEDLINE | ID: mdl-31336099

ABSTRACT

The LIFTED model of early face perception postulates that the face-sensitive N170 event-related potential may reflect underlying neural inhibition mechanisms which serve to regulate holistic and featural processing. It remains unclear, however, what specific factors impact these neural inhibition processes. Here, N170 peak responses were recorded whilst adults maintained fixation on a single eye using a gaze-contingent paradigm, and the presence/absence of a face outline, as well as the number and type of parafoveal features within the outline, were manipulated. N170 amplitudes and latencies were reduced when a single eye was fixated within a face outline compared to fixation on the same eye in isolation, demonstrating that the simple presence of a face outline is sufficient to elicit a shift towards a more face-like neural response. A monotonic decrease in the N170 amplitude and latency was observed with increasing numbers of parafoveal features, and the type of feature(s) present in parafovea further modulated this early face response. These results support the idea of neural inhibition exerted by parafoveal features onto the foveated feature as a function of the number, and possibly the nature, of parafoveal features. Specifically, the results suggest the use of a feature saliency framework (eyes > mouth > nose) at the neural level, such that the parafoveal eye may play a role in down-regulating the response to the other eye (in fovea) more so than the nose or the mouth. These results confirm the importance of parafoveal features and the face outline in the neural inhibition mechanism, and provide further support for a feature saliency mechanism guiding early face perception.


Subject(s)
Brain/physiology , Evoked Potentials, Visual , Facial Recognition/physiology , Neural Inhibition/physiology , Adult , Electroencephalography , Eye , Eye Movement Measurements , Face , Female , Fixation, Ocular , Humans , Male , Photic Stimulation , Young Adult
2.
Brain Sci ; 9(5)2019 May 17.
Article in English | MEDLINE | ID: mdl-31109022

ABSTRACT

Faces showing expressions of happiness or anger were presented together with sentences that described happiness-inducing or anger-inducing situations. Two main variables were manipulated: (i) congruency between contexts and expressions (congruent/incongruent) and (ii) the task assigned to the participant, discriminating the emotion shown by the target face (emotion task) or judging whether the expression shown by the face was congruent or not with the context (congruency task). Behavioral and electrophysiological results (event-related potentials (ERP)) showed that processing facial expressions was jointly influenced by congruency and task demands. ERP results revealed task effects at frontal sites, with larger positive amplitudes between 250-450 ms in the congruency task, reflecting the higher cognitive effort required by this task. Effects of congruency appeared at latencies and locations corresponding to the early posterior negativity (EPN) and late positive potential (LPP) components that have previously been found to be sensitive to emotion and affective congruency. The magnitude and spatial distribution of the congruency effects varied depending on the task and the target expression. These results are discussed in terms of the modulatory role of context on facial expression processing and the different mechanisms underlying the processing of expressions of positive and negative emotions.

3.
Cortex ; 109: 35-49, 2018 12.
Article in English | MEDLINE | ID: mdl-30286305

ABSTRACT

The N170 event-related potential component is an early marker of face perception that is particularly sensitive to isolated eye regions and to eye fixations within a face. Here, this eye sensitivity was tested further by measuring the N170 to isolated facial features and to the same features fixated within a face, using a gaze-contingent procedure. The neural response to single isolated eyes and eye regions (two eyes) was also compared. Pixel intensity and contrast were controlled at the global (image) and local (featural) levels. Consistent with previous findings, larger N170 amplitudes were elicited when the left or right eye was fixated within a face, compared to the mouth or nose, demonstrating that the N170 eye sensitivity reflects higher-order perceptual processes and not merely low-level perceptual effects. The N170 was also largest and most delayed for isolated features, compared to equivalent fixations within a face. Specifically, mouth fixation yielded the largest amplitude difference, and nose fixation yielded the largest latency difference between these two contexts, suggesting the N170 may reflect a complex interplay between holistic and featural processes. Critically, eye regions elicited consistently larger and shorter N170 responses compared to single eyes, with enhanced responses for contralateral eye content, irrespective of eye or nasion fixation. These results confirm the importance of the eyes in early face perception, and provide novel evidence of an increased sensitivity to the presence of two symmetric eyes compared to only one eye, consistent with a neural eye region detector rather than an eye detector per se.


Subject(s)
Evoked Potentials, Visual/physiology , Facial Recognition/physiology , Neural Inhibition/physiology , Visual Cortex/physiology , Visual Perception/physiology , Electroencephalography , Female , Functional Laterality/physiology , Humans , Male , Orientation/physiology , Photic Stimulation , Young Adult
4.
J Commun Disord ; 63: 32-46, 2016.
Article in English | MEDLINE | ID: mdl-27814796

ABSTRACT

The purpose of this article is to describe the results of a thematic analysis of 79 semi-structured interviews collected at six research sites in four countries in relation to the inclusion and exclusion of students with developmental disabilities (DD) in and from special education and bilingual opportunities. The participants were individuals with expertise either in special needs and/or language education to support bilingualism (e.g., second language (L2) instruction), who served as key informants about service delivery and/or policy in these areas. Six themes emerged as salient during the analysis: we include all kids, special needs drives it, time/scheduling conflicts, IEP/IPP/statement drives it, it's up to the parents, and service availability. The results suggested that access to language programs and services is limited for children with DD, even though participants at all sites reported adherence to a philosophy of inclusion. A priority on special education services over language services was identified, as well as barriers to providing children with DD access to programs and services to support bilingual development. Some of these barriers included time and scheduling conflicts and limited service availability. Additionally, the role of parents in decision making was affirmed, although, in contrast to special education services, decision-making about participation or exemption from language programs was typically left up to the parents. Overall, the results suggest a need for greater attention to providing supports for both first (L1) and L2 language development for bilingual children with DD and greater access to available language programs.


Subject(s)
Developmental Disabilities/psychology , Education, Special , Interviews as Topic , Language Development , Multilingualism , Child , Choice Behavior , Humans , Internationality , Parents , Time Factors
5.
J Commun Disord ; 63: 47-62, 2016.
Article in English | MEDLINE | ID: mdl-27814797

ABSTRACT

This study aimed to gather information from school- and clinic-based professionals about their practices and opinions pertaining to the provision of bilingual supports to students with developmental disabilities. Using an online survey, data were collected in six socio-culturally and linguistically diverse locations across four countries: the United States, Canada, the United Kingdom, and the Netherlands. In total, 361 surveys were included in the analysis from respondents who were primarily teachers and speech-language pathologists working in schools, daycares/preschools, or community-based clinics. The overall picture that emerged from the data reflected a disconnection between practice and opinion. In general, respondents believed that children with both mild and severe disabilities are capable of learning a second language, although their opinions were more neutral for the latter group. However, children with both mild and severe disabilities who spoke only a minority language at home had less access to services for second language learners than did their typically developing peers, although respondents agreed that such services should be more available. Regardless of clinical group, children who lived in homes where a minority language was spoken were often exposed to, assessed in, and treated in the majority language only; again, respondents generally disagreed with these practices. Finally, second language classes were less available to children in the two disability groups compared to typically developing bilingual children, with general agreement that the opportunity to acquire a second language should be more available, especially to those with mild disabilities. Although the results indicate that there is a considerable gap between current practices and professional opinions, professionals appear to be more supportive of bilingual educational opportunities for these populations than was suggested by previous research.


Subject(s)
Developmental Disabilities/psychology , Multilingualism , Professional Practice , Adult , Child , Female , Humans , Internationality , Internet , Language Therapy/methods , Male , Middle Aged , Minority Groups/psychology , Speech-Language Pathology/education , Surveys and Questionnaires
6.
Exp Brain Res ; 233(10): 2883-95, 2015 Oct.
Article in English | MEDLINE | ID: mdl-26105755

ABSTRACT

We examined how performance on an associative learning task changes in a sample of undergraduate students as a function of their autism-spectrum quotient (AQ) score. The participants, without any prior knowledge of the Japanese language, learned to associate hiragana characters with button responses. In the novel condition, 50 participants learned visual-motor associations without any prior exposure to the stimuli's visual attributes. In the familiar condition, a different set of 50 participants completed a session in which they first became familiar with the stimuli's visual appearance prior to completing the visual-motor association learning task. Participants with higher AQ scores had a clear advantage in the novel condition; the amount of training required reaching learning criterion correlated negatively with AQ. In contrast, participants with lower AQ scores had a clear advantage in the familiar condition; the amount of training required to reach learning criterion correlated positively with AQ. An examination of how each of the AQ subscales correlated with these learning patterns revealed that abilities in visual discrimination-which is known to depend on the visual ventral-stream system-may have afforded an advantage in the novel condition for the participants with the higher AQ scores, whereas abilities in attention switching-which are known to require mechanisms in the prefrontal cortex-may have afforded an advantage in the familiar condition for the participants with the lower AQ scores.


Subject(s)
Association Learning/physiology , Autism Spectrum Disorder/physiopathology , Executive Function/physiology , Pattern Recognition, Visual/physiology , Psychomotor Performance/physiology , Adult , Female , Humans , Male , Students , Universities , Young Adult
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