Document Detail

Neural noise limitations on infant visual sensitivity.
MedLine Citation:
PMID:  9490413     Owner:  NLM     Status:  MEDLINE    
Visual contrast sensitivity is poor in newborn human infants, but improves rapidly to approach adult levels by 8 months of age. During this period, infant sensitivity can be limited by physical factors affecting photon capture, such as eye size and photoreceptor density. Here we show that infant visual sensitivity is also limited by high levels of noise in the neural transduction process. Using a non-invasive electrophysiological measurement and a visual noise titration technique, we have found that intrinsic neural noise in neonates is approximately nine times higher than in adults. As intrinsic neural noise decreases during infancy, contrast sensitivity improves proportionally, suggesting that neural noise places critical limits on contrast sensitivity throughout development. Moreover, contrast gain control, an inhibitory process that adjusts visual responses to changing stimulation, is in place and operating in infants as young as 6 weeks of age, in spite of high levels of neural noise and significant immaturities in contrast sensitivity. The contrast gain control that we observed in human neonates may serve as a building block for more complex forms of visual inhibition, which develop later in infancy.
A M Skoczenski; A M Norcia
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Nature     Volume:  391     ISSN:  0028-0836     ISO Abbreviation:  Nature     Publication Date:  1998 Feb 
Date Detail:
Created Date:  1998-03-02     Completed Date:  1998-03-02     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0410462     Medline TA:  Nature     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  697-700     Citation Subset:  IM    
Smith-Kettlewell Eye Research Institute, San Francisco, California 94115, USA.
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MeSH Terms
Aging / physiology
Contrast Sensitivity / physiology*
Evoked Potentials, Visual
Infant, Newborn / physiology*
Neural Conduction / physiology*
Sensory Thresholds

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