Logo image
Back
The critical period for alteration in cortical binocularity resulting from divergent and convergent strabismus
Journal article   Peer reviewed

The critical period for alteration in cortical binocularity resulting from divergent and convergent strabismus

Nancy Berman and E.Hazel Murphy
Brain research. Developmental brain research, v 2(2), pp 181-202
1981
DOI: https://doi.org/10.1016/0165-3806(81)90031-6
PMID: 7272776

Abstract

critical period effects of experience receptive fields strabismus vision visual cortex
Kittens were reared with unilateral convergent (esotropia) or divergent (exotropia) strabismus which was surgically induced at different ages during the first 3 months. Visual field testing at ages 3–4 1 2 months showed no loss of the nasal field in esotropic kittens and a slight loss of the nasal field in exotropic kittens. Recording from single units in area 17 showed that early surgically induced strabismus results in a loss of binocularity of cortical cells and an increase in the size of the receptive fields of the cells. However, the critical periods for the two effects differ, with the critical period for the loss of cortical binocularity ending before the critical period for the abnormally large receptive fields. A special group of complex cells, the complex-spot cells, was relatively resistant to the loss of binocularity caused by strabismus. In both esotropic and exotropic animals the normal eye dominated more units than the operated eye. Although the major effects of esotropia and exotropia in cortical physiology were similar, some differences were found between the two groups. In the esotropic cats, the few binocularly driven units had receptive fields significantly larger than the monocularly driven units. In contrast, in the exotropic cats there was no significant differences in receptive field size of monocularly and binocularly driven units. In esotropic animals complex cells driven by the strabismic eye had larger receptive fields than complex cells driven by the unoperated eye. This difference did not occur in exotropic animals. In addition, the overall percentage of binocularly driven units was higher in exotropic (25%) than in esotropic (13%) animals. These results suggest that functional abnormalities in the visual cortex are slightly more severe in esotropic animals than in exotropic ones.

Metrics

7 Record Views
29 citations in Web of Science
39 citations in Scopus

Details

InCites Highlights

Data related to this publication, from InCites Benchmarking & Analytics tool:

Web of Science research areas
Developmental Biology
Neurosciences
Logo image