Visual cortical cells: their developmental properties in normal and dark reared kittens

Area of Science:

• Neuroscience
• Developmental Neuroscience
• Visual System Research

Background:

• The development of the visual cortex involves the emergence of neurons with specific response properties.
• Understanding the role of early visual experience in shaping neuronal function is critical.

Purpose of the Study:

• To investigate the presence and development of orientation-specific neurons in the visual cortex of kittens.
• To determine the impact of early visual deprivation on the maturation of these neuronal properties.

Main Methods:

• Electrophysiological recordings were performed in area 17 of normally reared and dark-reared kittens (8-42 days old).
• Neuronal responses to visual stimuli were classified into four types: non-activable, non-specific, immature, and specific cells.
• The proportion of different cell types was analyzed in relation to age and visual rearing conditions.

Main Results:

• Specific cells, exhibiting adult-like orientation selectivity, were found in both normally and dark-reared kittens at the onset of visual responsiveness (12 days).
• In normally reared kittens, the proportion of specific cells increased with age, while non-specific cells decreased.
• Dark-reared kittens showed a significant decrease in specific cells and an increase in non-specific cells after three weeks of age, differing from normally reared counterparts.

Conclusions:

• Orientation-specific visual cortical neurons are present early in development, independent of visual experience.
• Postnatal visual experience is essential for the maintenance and further development of these specific neuronal properties beyond the critical early period.