Visual loss alters multisensory face maps in humans

Area of Science:

• Neuroscience
• Sensory processing
• Brain plasticity

Background:

• The ventral intraparietal cortex shows topographically organized responses to visual and tactile stimuli.
• This region is crucial for visually guided defensive movements, implying innate neural maps.
• The necessity of visual experience for map formation remains unclear.

Purpose of the Study:

• To investigate if visual experience is required for the development and precise localization of topographic maps in the intraparietal cortex.
• To compare tactile map organization in individuals blind from birth versus those who lost vision later.
• To explore individual differences in functional neuroanatomy related to visual impairment.

Main Methods:

• Functional neuroimaging was used to assess tactile stimulation responses.
• Participants included individuals with congenital total blindness and late total blindness.
• A single-subject analysis approach was employed to examine individual variations.

Main Results:

• No significant overall difference was found between congenitally and late blind participants regarding tactile map organization.
• Single-subject analyses indicated that visual experience is not necessary for establishing topographic maps in the intraparietal cortex.
• Acquired blindness was associated with disruptions in the integrity and organization of these topographic maps.

Conclusions:

• Topographic maps in the intraparietal cortex can develop without visual experience.
• The findings highlight the brain's plasticity but also the impact of vision loss on established neural organization.
• The results contribute to understanding sensitive periods and neuroplasticity in sensory processing.