Persisting Cross-Modal Changes in Sight-Recovery Individuals Modulate Visual Perception.

Recent neuroimaging studies have demonstrated that a brief period of congenital blindness induces long-lasting reorganization within the visual cortex of sight-recovery humans [1, 2]. However, the behavioral consequences of this cross-modal reorganization are not yet known. Here we investigated this question by examining the transfer of motion aftereffects across the visual and auditory modalities within six individuals who had been born blind due to dense bilateral cataracts and regained sight when they were treated at 5-24 months of age.

The Effect of Early Visual Deprivation on the Neural Bases of Auditory Processing.

Unlabelled: Transient congenital visual deprivation affects visual and multisensory processing. In contrast, the extent to which it affects auditory processing has not been investigated systematically. Research in permanently blind individuals has revealed brain reorganization during auditory processing, involving both intramodal and crossmodal plasticity.

Increased visual cortical thickness in sight-recovery individuals.

Individuals who are born blind due to dense bilateral cataracts and who later regain vision due to cataract surgery provide a unique model to evaluate the effect of early sensory experience in humans. In recent years, several studies have started to assess the functional consequences of early visual deprivation in these individuals, revealing a number of behavioral impairments in visual and multisensory functions. In contrast, the extent to which a transient period of congenital visual deprivation impacts brain structure has not yet been investigated.

The effect of early visual deprivation on the neural bases of multisensory processing.

Developmental vision is deemed to be necessary for the maturation of multisensory cortical circuits. Thus far, this has only been investigated in animal studies, which have shown that congenital visual deprivation markedly reduces the capability of neurons to integrate cross-modal inputs. The present study investigated the effect of transient congenital visual deprivation on the neural mechanisms of multisensory processing in humans.

Basic multisensory functions can be acquired after congenital visual pattern deprivation in humans.

People treated for bilateral congenital cataracts offer a model to study the influence of visual deprivation in early infancy on visual and multisensory development. We investigated cross-modal integration capabilities in cataract patients using a simple detection task that provided redundant information to two different senses. In both patients and controls, redundancy gains were consistent with coactivation models, indicating an integrated processing of modality-specific information.

Early visual deprivation affects the development of face recognition and of audio-visual speech perception.

Purpose: The investigation of patients treated for bilateral congenital cataracts allows to study the development of visual and multisensory functions after a period of visual deprivation in early infancy. In the present study, cataract patients were tested for their capability to recognize faces and to integrate auditory and visual speech information.

Methods: In Experiment 1, 12 cataract patients were tested with the Benton Facial Recognition Test.

The neural basis of lip-reading capabilities is altered by early visual deprivation.

The present study investigated the neural basis of lip-reading in patients treated for congenital bilateral cataracts using functional magnetic resonance imaging (fMRI). These patients represent a model to study the role of visual experience in early infancy for the development of visual functions. Short video clips with an adult speaker's lips mouthing different words were presented.

Early visual deprivation impairs multisensory interactions in humans.

Animal studies have shown that visual deprivation during the first months of life permanently impairs the interactions between sensory systems. Here we report an analogous effect for humans who had been deprived of pattern vision for at least the first five months of their life as a result of congenital binocular cataracts. These patients showed reduced audio-visual interactions in later life, although their visual performance in control tasks was unimpaired.

The development of visual feature binding processes after visual deprivation in early infancy.

Higher visual functions were investigated in patients treated for bilateral congenital cataracts in two experiments. Participants were asked to detect either real or illusory contours (Kanizsa squares in Experiment 1 or one of four different Kanizsa contours in Experiment 2) among distractor items. Compared to normally sighted participants matched for age, gender and education, cataract patients treated after the age of 5-6 months took relatively longer to detect Kanizsa figures (Experiments 1 and 2) and they had higher miss rates (Experiment 2).