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A transient geniculo-extrastriate pathway in macaques? Implications for 'blindsight'
1Department of Psychology, Yerkes Regional Primate Research Center, Emory University, Atlanta, GA 30322, USA.
Neuroreport
|December 22, 1999
Summary
Infant monkeys with visual cortex damage show better vision recovery than adults. Unlike cats, infant primates lack a specific transient pathway from the dorsal lateral geniculate nucleus to visual areas, suggesting a different recovery mechanism.
Area of Science:
- Neuroscience
- Visual System Development
- Comparative Neurology
Background:
- Early-life damage to the primary visual cortex (V1) in animals results in better vision recovery compared to adult-onset damage.
- In cats, this enhanced recovery is partly attributed to a transient pathway from the dorsal lateral geniculate nucleus (dLGN) to visual area PMLS.
Purpose of the Study:
- To investigate if a similar transient dLGN pathway to dorsal extrastriate areas exists in infant primates.
- To determine if such a pathway could be recruited for vision recovery after early V1 lesions in primates.
Main Methods:
- Retrograde tracers were injected into areas MT, MST, and/or 7a in infant macaques.
- The study examined projections from the dLGN to these dorsal extrastriate visual areas.
Main Results:
- No evidence of a transient pathway from the dLGN to the targeted dorsal extrastriate areas (MT, MST, 7a) was found in infant macaques.
- Projections from the pulvinar and other extrastriate areas to these regions were observed.
Conclusions:
- Infant primates do not appear to utilize a transient dLGN pathway to dorsal extrastriate areas for vision recovery after early V1 damage.
- Alternative mechanisms, potentially involving projections from the pulvinar or other extrastriate areas, may underlie the observed recovery in primates.