Decoding Reach Direction in Early "Visual" Cortex of Congenitally Blind Individuals

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Sensory Processing

Background:

• The early visual cortex (EVC) was traditionally believed to process only visual input.
• Emerging research suggests EVC involvement in non-visual functions, including action processing.
• It remains debated whether this processing relies on visual imagery or is independent of visual experience.

Purpose of the Study:

• To investigate whether the early visual cortex (EVC) in congenitally blind humans can represent action-related information.
• To determine if visual experience or imagery is necessary for EVC's role in action representation.
• To explore the spatial organization of action representations within the EVC and other brain areas in the absence of vision.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was used to measure brain activity.
• Researchers decoded reach direction from EVC activity in individuals with congenital blindness.
• Decoding accuracy was analyzed across different EVC subregions and within dorsal stream areas.

Main Results:

• Reach direction could be reliably decoded from the EVC of congenitally blind individuals.
• Neither visual experience nor visual imagery was necessary for this action representation in EVC.
• Decoding accuracy was highest in foveal-representative EVC areas and decreased in peripheral areas, suggesting a potential hard-wired alignment mechanism.
• Action representations were also found in dorsal stream areas critical for visuo-motor integration in sighted individuals.

Conclusions:

• The early visual cortex (EVC) can represent motor actions independently of visual experience or imagery.
• The brain develops action and spatial representations even without lifelong vision.
• Findings suggest that the neural basis of action representation may be largely independent of visual input.