Neural and behavioral correlates of drawing objects and scenes in an early blind painter.

Amir Amedi, Center for Non-Invasive Magnetic Brain Stimulation, Dept. of Neurology, BIDMC, Harvard Medical School

Abstract
Subject EA is a congenitally blind painter. He has an extraordinary ability to comprehend the shape of an object by touch and draw it from any vantage point so that it can be unequivocally identified visually. Given the fact that EA has never seen his drawings, he must possess internal representations of the objects and scenes consistent with visual
frames of reference, not just tactile ones. Our aim was to study the neural basis for EA’s drawing abilities, as compared with tactile exploration or imagery. We studied EA using an fMRI block design paradigm while he palpated objects, drew them, imagined their shape, scribbled on a piece of paper, or completed motor and verbal memory controls. EA shows prominent activation of early visual cortex (including V1) for drawing versus scribbling. Remarkably, he does not read Braille, so that recruitment of the visual cortex in EA has taken place independently of Braille or verbal representation. Contrary to other early blind subjects, EA does not activate visual areas during verbal memory. This might be because the resources of the 'visual' cortex are recruited for his remarkable drawing ability, thus being less available for verbal memory, which is EA is quite poor.

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