Lexical-semantic activation in Broca's and Wernicke's aphasia: evidence from eye movements.

Full Abstract

Lexical processing requires both activating stored representations and selecting among active candidates. The current work uses an eye-tracking paradigm to conduct a detailed temporal investigation of lexical processing. Patients with Broca's and Wernicke's aphasia are studied to shed light on the roles of anterior and posterior brain regions in lexical processing as well as the effects of lexical competition on such processing. Experiment 1 investigates whether objects semantically related to an uttered word are preferentially fixated, for example, given the auditory target "hammer," do participants fixate a picture of a nail? Results show that, like normal controls, both groups of patients are more likely to fixate on an object semantically related to the target than an unrelated object. Experiment 2 explores whether Broca's and Wernicke's aphasics show competition effects when words share onsets with the uttered word, for instance, given the auditory target "hammer," do participants fixate a picture of a hammock? Experiment 3 investigates whether these patients activate words semantically related to onset competitors of the uttered word, for example, given the auditory target "hammock," do participants fixate a nail due to partial activation of the onset competitor hammer? Results of Experiments 2 and 3 show pathological patterns of performance for both Broca's and Wernicke's aphasics under conditions of lexical onset competition. However, the patterns of deficit differed, suggesting different functional and computational roles for anterior and posterior areas in lexical processing. Implications of the findings for the functional architecture of the lexical processing system and its potential neural substrates are considered.

Author information

Author/s: Yee, Eiling (E); Blumstein, Sheila E (SE); Sedivy, Julie C (JC);

Affiliation: Department of Psychology, University of Pennsylvania, Philadelphia, PA 19104-6241, USA. eiling(-atsign-)psych.upenn.edu

Grants: NIDCD00314 (Agency:PHS HHS) ; NIDCD0081 (Agency:PHS HHS)

Journal and publication information

Publication Type: Comparative Study; Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't

Journal: Journal of cognitive neuroscience (J Cogn Neurosci), published in United States. (Language: eng)

Reference: 2008-Apr; vol 20 (issue 4) : pp 592-612

Dates: Created 2008/03/07; Completed 2008/05/15;

PMID: 18052783, status: MEDLINE (last retrieval date: 2/18/2009, IMS Date: )

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

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