1. Development of contrast normalization mechanisms during childhood and adolescence
- Author
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Holly E. Gerhard, Francesca Pei, Stefano Baldassi, Jeffrey J. Tsai, and Anthony M. Norcia
- Subjects
Male ,medicine.medical_specialty ,Adolescent ,Visual evoked potentials ,Audiology ,Stimulus (physiology) ,Contrast Sensitivity ,03 medical and health sciences ,Child Development ,0302 clinical medicine ,Optics ,Visual masking ,medicine ,Humans ,Child ,Visual Cortex ,business.industry ,Sensory Systems ,Ophthalmology ,Pattern Recognition, Visual ,Child, Preschool ,Sensory Thresholds ,030221 ophthalmology & optometry ,Evoked Potentials, Visual ,Female ,Contrast response function ,business ,Psychology ,Perceptual Masking ,030217 neurology & neurosurgery - Abstract
Contrast sensitivity is regulated by neural mechanisms that flexibly adjust responsiveness to optimize stimulus encoding across different environments. Here we studied the developmental status of gain control mechanisms in school-age children (5–17 years) and adults using a visual masking paradigm. A variable contrast, spatially random 2-D noise test pattern was masked by the presence of a superimposed independent noise pattern presented at 0, 12 and 40% contrast. Frequency-tagged steady state visual evoked potentials were used to separately record responses to the test (5.14 Hz) and the mask (7.2 Hz). By incrementally increasing the test contrast we measured contrast response functions for each mask contrast. The unmasked contrast response functions were largely similar in shape across age, but peak amplitude was higher in the children. Masking shifted the contrast response function rightward on the contrast axis in both the adults and older children, elevating contrast thresholds by a similar factor across age. However, in younger children, masking resulted in a change in the slope of the contrast response function. These findings suggest that immaturity in the contrast normalization process persists until approximately 11 years of age.
- Published
- 2017