Early-onset binocularity in preterm infants reveals experience-dependent visual development in humans

Area of Science:

• Neuroscience
• Developmental Neuroscience
• Visual Neuroscience

Background:

• Neocortical plasticity and environmental influences on the newborn brain are debated.
• Binocular vision (stereopsis) is a key model for experience-dependent development.
• The impact of postnatal visual experience on preterm infant brain development requires further investigation.

Purpose of the Study:

• To investigate the effect of extra postnatal visual experience on the developmental timing of binocular vision in preterm infants.
• To assess the integrity of the visual pathway in preterm and full-term infants.
• To determine the role of experience-dependent mechanisms in the onset of stereopsis.

Main Methods:

• Measured visual evoked responses to dynamic random dot correlograms (DRDC-VEP) to assess binocular function onset.
• Measured visual evoked responses to pattern reversal stimuli (PR-VEP) to evaluate visual pathway integrity.
• Compared DRDC-VEP and PR-VEP in preterm and full-term neonates.

Main Results:

• The onset age of binocular function (DRDC-VEP) was similar in preterm (4.07 months) and full-term (3.78 months) infants.
• Pattern reversal visual evoked response (PR-VEP) latency was unaffected by premature birth, indicating a preprogrammed visual pathway maturation.
• Despite immature visual pathways (PR-VEP), the visual cortex showed readiness for environmental stimulation, leading to earlier cortical binocularity in preterm infants.

Conclusions:

• The maturation of the visual pathway is largely preprogrammed.
• Early postnatal visual experience significantly influences the developmental timing of binocular vision onset.
• The mechanisms initiating stereopsis in humans are highly experience-dependent, not preprogrammed.