Biomedical subjects

Hanife Halit

Publications and source records attributed to Hanife Halit.

6 recordsLinked to original sources

PubMed2005

Neural correlates of eye-gaze detection in young children with autism.

Various reports have demonstrated difficulties in eye-gaze processing in older children and adults with autism. However, little is known about the neural or developmental origin of such difficulties. In the present study, we used high-density Event-Related Potentials (HD-ERPs) to record the neural correlates of gaze processing in young children with autism, and their age-matched controls. In addition, to determine normal gaze processing development we also tested a non-autism adult group. The data obtained from the children with autism resembled that previously observed in typical 4-month old infants. In contrast, the control group showed the same pattern as typical adults. These findings suggest that the neural correlates of gaze direction processing may be delayed in young children with autism.

Adult↗

PubMed2005

The emergence of the social brain network: evidence from typical and atypical development.

Several research groups have identified a network of regions of the adult cortex that are activated during social perception and cognition tasks. In this paper we focus on the development of components of this social brain network during early childhood and test aspects of a particular viewpoint on human functional brain development: "interactive specialization." Specifically, we apply new data analysis techniques to a previously published data set of event-related potential (ERP) studies involving 3-, 4-, and 12-month-old infants viewing faces of different orientation and direction of eye gaze. Using source separation and localization methods, several likely generators of scalp recorded ERP are identified, and we describe how they are modulated by stimulus characteristics. We then review the results of a series of experiments concerned with perceiving and acting on eye gaze, before reporting on a new experiment involving young children with autism. Finally, we discuss predictions based on the atypical emergence of the social brain network.

Adult↗

PubMed2004

Face-sensitive cortical processing in early infancy.

BACKGROUND: Debates about the developmental origins of adult face processing could be directly addressed if a clear infant neural marker could be identified. Previous research with infants remains open to criticism regarding the control stimuli employed. METHODS: We recorded ERPs from adults and 3-month-old infants while they watched faces and matched visual noise stimuli. RESULTS: We observed similar amplitude enhancement for faces in the infant N290 and adult N170. In contrast, the infant P400 showed only a latency effect, making it unlikely to be the main precursor of the adult N170. CONCLUSIONS: We conclude that there is some degree of specificity of cortical processing of faces as early as 3 months of age.

Adult↗

PubMed2003

ERP abnormalities of illusory contour perception in Williams syndrome.

Williams syndrome is a genetic disorder in which visuo-spatial performance is poor. Theorists have claimed that the deficit lies in high-level processing, leaving low-level visual processes intact. We investigated this claim by examining an aspect of low-level processing, perceptual completion, i.e. the ability of this clinical group to perceive illusory Kanizsa squares. We then used event-related potentials to examine neural correlates of perceptual completion. While participants were able to perceive illusory contours, the neural correlates of this apparently normal perception were different from controls. Such differences in low-level visual processes may significantly impact on the development of higher-level visual processes. We conclude that, contrary to earlier claims, there is atypical neural processing during low-level visual perception in Williams syndrome.

Adolescent↗

PubMed2003

Development of face-sensitive event-related potentials during infancy: a review.

Event-related potential (ERP) studies in adults have identified a number of components related to encoding and recognition memory of faces. Although behavioural studies indicate that even very young infants are able to detect faces and recognise familiar individuals, very few ERP studies document the neural correlates of these early abilities. In this article, we review four components (P1, N290, P400, Nc) and slow wave activity that are elicited while infants view faces. Where possible we draw links between these components and their possible equivalents to those observed in children and adults, and we highlight areas where further investigation is required. The theoretical importance of ERP studies of face processing in infants for debates about the origins and domain specificity of the adult cortical face processing system are discussed.

Child, Preschool↗

PubMed2002

Neuroimaging of typical and atypical development: a perspective from multiple levels of analysis.

To date, research involving functional neuroimaging of typical and atypical development has depended on several assumptions about the postnatal maturation of the brain. We consider evidence from multiple levels of analysis that brings into question these underlying assumptions and advance an alternative view. This alternative view, based on an "interactive specialization" approach to postnatal brain development, indicates that there is a need to: obtain data from early in development; focus more on differences in interregional interactions rather than searching for localized, discrete lesions; examine the temporal dynamics of neural processing; and move away from deficits to image tasks in which atypical participants perform as well as typically developing participants.

Brain↗