The role of crossed and uncrossed optic pathways mediating black-white discrimination in rats with one eye enucleated at birth

Ikeda, Yukinobu; Yagi, Fumio; Sakai, Makoto

doi:10.1016/0031-9384(83)90253-6

Cited by 14 publications

(3 citation statements)

References 18 publications

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“…This "faster" relearning phenomenon of OEBs is considered to be a behavioral expression of the above mentioned reorganization in the visual system. However, our previous studies (Ikeda et al, 1988;Ikeda et al, 1992;Ikeda et al, 1983;Sakai et al, 1991;Sakai et al, 1996;Yagi & Sakai, 1979;Yagi et al, 1989) have also demonstrated that neither OEBs nor OETs are able to master BW discrimination when the discrimination training is given at 3 months of age and made 10 days after damage of the CT visual cortex. We interpret the reason for the inability to discriminate as follows: In postoperative original learning, rats have to learn to extract the experimenter's defined relevant cues for discrimination from various kinds of potential stimuli, and this might still be difficult, even for OEBs that possess expanded uncrossed visual pathways.…”

Section: Introductionmentioning

confidence: 88%

“…The training apparatus was a modification of the shock-avoidance discrimination box originally devised by Thompson and Bryant (1955), in which the animals were trained on BW discrimination (black 6.2 cd/m2, white 202.1 cd/m2) by basically the same procedures as those employed in previous studies (e.g., Ikeda et al, 1983). Briefly, the white door was the positive stimulus, and the electrical shock (50 Y, AC) was given from the floor grids.…”

Section: Cortical Lesionmentioning

confidence: 99%

“…Behaviorally, 3-month-old rats with one eye removed at birth (OEBs) can relearn a black-white (BW) discrimination faster than those rats with one eye removed at 13 weeks of age (OETs), when relearning is initiated 10 days after lesions of the visual cortex contralateral to the remaining eye (CT visual cortex). In this case the CT visual cortex lesions are made the day following the completion of original learning (Ikeda, Sakai, & Yagi,1988;Ikeda, Sakai, & Yagi, 1992;Ikeda, Yagi, & Sakai, 1983;Sakai, Ikeda, & Yagi, 1991;Sakai, Ikeda, & Yagi, 1996;Yagi & Sakai, 1979;Yagi, Sakai, & Ikeda, 1989). This "faster" relearning phenomenon of OEBs is considered to be a behavioral expression of the above mentioned reorganization in the visual system.…”

Section: Introductionmentioning

confidence: 99%

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Long-term unilateral visual cortical lesions and learning of a black-white discrimination by one-eyed rats

Ikeda

Sakai

Yagi

2000

Jpn. J. Physiol. Psychol. Psychophysiol.

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In a previous study we investigated the effects of callosal transected lesions made 10 weeks earlier (the 10-week-old callosal transected lesions), either at 3 weeks of age or at 13 weeks of age, upon the acquisition of a black-white (BW) discrimination in rats either with one eye removed at birth (OEB) or at 13 weeks of age (OET) following lesions of the contralateral (CT) visual cortex to the remaining eye. The CT visual cortex lesions were performed right before the training of BW discrimination. We found that the 10-week-old callosal transected lesions facilitated the acquisition in OEBs when the callosal lesions were given at 3 weeks of age, and to a lesser extent at 13 weeks of age. We also found that the same type of callosal transected lesions did not do so in OETs, regardless of the age when the callosal lesions were made.Since the CT visual cortex lesions inevitably result in damage of the callosal neurons, and lead to degeneration of the callosal afferents in the ipsilateral (IP) visual cortex, the present study was undertaken to investigate if the CT visual cortex lesions made 10 weeks earlier (the 10-week-old CT visual cortex lesions), made either at 3 weeks of age or 13 weeks of age, would affect the acquisition of BW discrimination in OEBs and OETs, like the 10-week-old callosal transected lesions employed in the previous study mentioned above.We found that in both OEBs and OETs the overall pattern of the facilitation effects of the 10-week-old CT visual cortex lesions on the acquisition of BW discrimination is, in general, the same as that observed in the 10-week-old callosal transected lesions, but the facilitative effect of the 10-week-old CT visual cortex lesions is more prevailing and pronounced. The findings are discussed in relation to the possible involvement of neurotrophic factors, released when the CT visual cortex lesions were made, in synaptic reorganization, and also in relation to the possibility of the increased use of the uncrossed visual pathways.

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