Blindsight is a phenomenon in which patients with damage to the primary visual cortex of the brain can tell where an object is, although they claim they cannot see it. The author examined the recovery process of monkeys with damage to one side of the primary visual cortex. Eye movement task training for 2–3 months enabled the monkeys to move their eyes to the correct directions in which an object was located, even in the affected side of their visual fi elds. Their brains became able to ‘feel’ where an object was, without ‘seeing’ it. After recovery, their eye movements looked almost normal. However, the author found two differences from the normal: 1) the trajectory of their eye movements was straight, and 2) their eye movement response time was short. The author concludes that after damage to the primary visual cortex, the monkeys’ eye movements were mediated by a qualitatively different vision, supported by brain circuits that bypass the primary visual cortex. These fi ndings will provide a new strategy for rehabilitating such patients; similar training may help them to know where an object is even without ‘seeing’ it.
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