Atypical perceptual processing of faces in developmental dyslexia.

Developmental Dyslexia (DD) is often attributed to phonological processing deficits. Recent evidence, however, indicates the need for a more general explanatory framework to account for DD's range of deficits. The current study examined the specificity versus domain generality of DD by comparing the recognition and discrimination of three visual categories (faces and words with cars as control stimuli) in typical and dyslexic readers.

Hemispheric Organization in Disorders of Development.

A recent theoretical account posits that, during the acquisition of word recognition in childhood, the pressure to couple visual and language representations in the left hemisphere (LH) results in competition with the LH representation of faces, which consequently become largely, albeit not exclusively, lateralized to the right hemisphere (RH). We explore predictions from this hypothesis using a hemifield behavioral paradigm with words and faces as stimuli, with concurrent ERP measurement, in a group of adults with developmental dyslexia (DD) or with congenital prosopagnosia (CP), and matched control participants. Behaviorally, the DD group exhibited clear deficits in both word and face processing relative to controls, while the CP group showed a specific deficit in face processing only.

Variable left-hemisphere language and orthographic lateralization reduces right-hemisphere face lateralization.

It is commonly believed that, in right-handed individuals, words and faces are processed by distinct neural systems: one in the left hemisphere (LH) for words and the other in the right hemisphere (RH) for faces. Emerging evidence suggests, however, that hemispheric selectivity for words and for faces may not be independent of each other. One recent account suggests that words become lateralized to the LH to interact more effectively with language regions, and subsequently, as a result of competition with words for representational space, faces become lateralized to the RH.

An ERP investigation of the co-development of hemispheric lateralization of face and word recognition.

The adult human brain would appear to have specialized and independent neural systems for the visual processing of words and faces. Extensive evidence has demonstrated greater selectivity for written words in the left over right hemisphere, and, conversely, greater selectivity for faces in the right over left hemisphere. This study examines the emergence of these complementary neural profiles, as well as the possible relationship between them.

Monocular advantage for face perception implicates subcortical mechanisms in adult humans.

The ability to recognize faces accurately and rapidly is an evolutionarily adaptive process. Most studies examining the neural correlates of face perception in adult humans have focused on a distributed cortical network of face-selective regions. There is, however, robust evidence from phylogenetic and ontogenetic studies that implicates subcortical structures, and recently, some investigations in adult humans indicate subcortical correlates of face perception as well.

The joint development of hemispheric lateralization for words and faces.

Consistent with long-standing findings from behavioral studies, neuroimaging investigations have identified a region of the inferior temporal cortex that, in adults, shows greater face selectivity in the right than left hemisphere and, conversely, a region that shows greater word selectivity in the left than right hemisphere. What has not been determined is how this pattern of mature hemispheric specialization emerges over the course of development. The present study examines the hemispheric superiority for faces and words in children, young adolescents and adults in a discrimination task in which stimuli are presented briefly in either hemifield.

Left visual field biases when infants process faces: a comparison of infants at high- and low-risk for autism spectrum disorder.

While it is well-known that individuals with autism spectrum disorder (ASD) have difficulties processing faces, very little is known about the origins of these deficits. The current study focused on 6- and 11-month-old infants who were at either high-risk (n = 43) or low-risk (n = 31) for developing ASD based on having a sibling already diagnosed with the disorder. Eye-tracking data were collected while the infants viewed color photographs of faces.

Category formation in autism: can individuals with autism form categories and prototypes of dot patterns?

There is a growing amount of evidence suggesting that individuals with autism have difficulty with categorization. One basic cognitive ability that may underlie this difficulty is the ability to abstract a prototype. The current study examined prototype and category formation with dot patterns in high-functioning adults with autism and matched controls.

A lack of left visual field bias when individuals with autism process faces.

It has been established that typically developing individuals have a bias to attend to facial information in the left visual field (LVF) more than in the right visual field. This bias is thought to arise from the right hemisphere's advantage for processing facial information, with evidence suggesting it to be driven by the configural demands of face processing. Considering research showing that individuals with autism have impaired face processing abilities, with marked deficits in configural processing, it was hypothesized that they would not demonstrate a LVF bias for faces.