Development of the Visual Cortex

Development of the Visual Cortex

Overview

  • The visual cortex is the part of the brain responsible for processing visual information.
  • Located in the occipital lobe, it is the largest system in the human brain and is responsible for visual perception and recognition.

Development Stages

  • The development of the visual cortex is a process that begins during the embryonic stage and continues postnatally.
  • The functionality of the human visual system is not fully developed at birth; it matures over time through a combination of biological growth and visual experience.

Role of Visual Experience in Development

  • Visual experience plays a critical role in the development and fine-tuning of the visual cortex.
  • Active visual exploration of the environment contributes to the strengthening and pruning of synaptic connections in the visual cortex.
  • If visual input during critical periods of development is deprived, it can lead to amblyopia or ‘lazy eye’, a condition of reduced vision.

Cortical Columns

  • The basic organisational unit of the visual cortex is the column.
  • Ocular dominance columns, comprising cells primarily responsive to input from one eye, alternate across the surface of the visual cortex.
  • The grant of different ocular dominance columns strengthens with visual experience during the critical period and is critical for binocular vision.

Plasticity

  • The visual cortex exhibits a high degree of plasticity during early stages of development.
  • Plasticity is influenced by the availability and quality of visual stimulation.
  • Postnatally, the visual cortex adapts to changes in visual input, reflecting its ongoing ability to learn from the environment.

Effects of Atypical Development

  • Neurodevelopmental disorders, such as autism and dyslexia, can affect the development, functioning, and plasticity of the visual cortex.
  • Altered development can also result from premature birth, congenital disorders, or exposure to certain toxins during prenatal development.

Insights from Animal Models

  • Much of our understanding of human visual cortex’s development comes from studies on animal models, particularly cats and monkeys.
  • For example, the concept of a critical period in visual development, where the visual cortex is particularly sensitive to environmental influences, was first established through animal studies.