Hostname: page-component-7b9c58cd5d-dlb68 Total loading time: 0 Render date: 2025-03-16T09:22:02.902Z Has data issue: false hasContentIssue false

Visual perception without awareness in a patient with posterior cortical atrophy: Impaired explicit but not implicit processing of global information

Published online by Cambridge University Press:  16 May 2002

J. VINCENT FILOTEO
Affiliation:
University of California, San Diego Veterans Administration Health Care System, San Diego, California
FRANCES J. FRIEDRICH
Affiliation:
University of Utah, Salt Lake City, Utah
CATHERINE RABBEL
Affiliation:
University of Utah, Salt Lake City, Utah
JOHN L. STRICKER
Affiliation:
SDSU/UCSD Joint Doctoral Program in Clinical Psychology, San Diego, California
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

A patient with progressive posterior cortical atrophy (PCA) was examined on several tests of visual cognition. The patient displayed multiple visual cognitive deficits, which included problems identifying degraded stimuli, attending to two or more stimuli simultaneously, recognizing faces, tracing simple visual stimuli, matching simple shapes, and copying objects. The patient was also impaired in identifying visual targets contained at the global level within global–local stimuli (i.e., smaller letters that compose a larger letter). Although the patient denied any conscious awareness of the global form, he nevertheless displayed a normal pattern of global interference when asked to identify local level targets. Thus, the patient processed the global information despite not being consciously aware of such information. These results suggest that global–local processing can take place in the absence of awareness. Possible neurocognitive mechanisms explaining this dissociation are discussed. (JINS, 2002, 8, 461–472.)

Type
CASE STUDY
Copyright
© 2002 The International Neuropsychological Society