[Morphological development of the primary visual pathway in the child]

Area of Science:

• Neuroscience
• Developmental Biology
• Visual System Research

Context:

• The human primary visual pathway, including the lateral geniculate nucleus (LGN) and visual cortex (area 17), undergoes significant developmental changes.
• Understanding neuronal morphology and synaptic development is crucial for comprehending visual system maturation.

Purpose:

• To characterize the developmental trajectory of neurons within the human lateral geniculate nucleus (LGN).
• To define the developmental stages of the human visual cortex (area 17) in relation to neuronal growth and synaptogenesis.
• To correlate early visual pathway development with periods of infant visual plasticity.

Summary:

• Human LGN neurons, identifiable at birth, exhibit immature features like spines that resolve by nine months post-natally as the LGN reaches adult volume.
• Area 17 shows two developmental stages: rapid growth and synaptogenesis by four months, followed by stabilization and synaptic density reduction by age 11.
• Transitory morphological features in the first year coincide with critical periods of infant visual plasticity, impacting acuity, stereopsis, and oculomotor function.

Impact:

• Provides a detailed timeline of human visual pathway development, from prenatal stages through childhood.
• Highlights the critical role of early visual experiences and the sensitivity of the developing visual system to deprivation.
• Offers insights into the neurobiological basis of visual development and potential targets for early intervention.