"Visual" Cortex Responds to Spoken Language in Blind Children.

Area of Science:

• Neuroscience
• Developmental Psychology
• Cognitive Science

Background:

• Cortical plasticity in blind individuals offers insights into brain specialization.
• Occipital (visual) brain regions in blind individuals can process auditory information.
• Developmental trajectory of this plasticity in children is largely unknown.

Purpose of the Study:

• To examine the time course and developmental mechanism of occipital plasticity in blind children.
• To investigate how the brain adapts in the absence of visual input.
• To understand the emergence of auditory processing in the visual cortex during childhood.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was used.
• Nineteen blind and 40 sighted children and adolescents (ages 4-17) participated.
• Participants listened to stories, unfamiliar foreign speech, and music.

Main Results:

• Young blind children's visual cortices responded to sound, unlike sighted children.
• Occipital responses to non-language sounds increased with age (4-17 years).
• Occipital responses to spoken language were maximal by age 4 and independent of Braille learning.

Conclusions:

• Spoken language processing occupies the visual cortex early in development in blind children.
• Occipital plasticity for spoken language is separate from plasticity for Braille and general sound processing.
• Early in development, human cortex exhibits broad computational capacity, adapting to various functions.