The Neuropsychology of Imagery Processing
Abstract
Progress has been made in six areas. First, a task battery to assess high-level visual abilities has been fully implemented. This battery is administered and scored on the Macintosh computer. Second, the task battery has been used to examine one patient in detail, and has diagnosed a subtle visual deficit that is consistent with both the lesion location and regions of hypometabolism (as measured by PET scanning). Third, additional brain-damaged patients have been tested in order to discover whether the visual angle subtended by imaged objects is systematically related to the amount of damage to the occipital lobe. Data from these three patients suggests such a relation. Fourth, the computer simulation of high-level vision is fully functional, and predictions have been generated about previously unnoticed syndromes. For example, the model predicts that some patients will be able to recognize faces but not common objects. Some of these predictions currently are being tested. Fifth, three subjects have been given imagery tasks while being PET scanned. The results are consistent with the predictions of the theory. In particular, the medial occipital and frontal activation is consistent with the claim that images are patterns of activation in topographically mapped areas and that they are built up sequentially. Finally, response time studies using divided visual field techniques have provided evidence for two ways of representing spatial relations, as categories (e.g., left/right; above/below) or precise metric amounts; the left hemisphere is generally more effective at computing categorical spatial relations, and the right hemisphere is generally more effective at computing metric spatial relations.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1989
- Accession Number
- ADA216479
Entities
People
- Stephen M. Kosslyn
Organizations
- Harvard University