Visual object agnosia is associated with a breakdown of object-selective responses in the lateral occipital cortex

NEUROPSYCHOLOGIA

卷:60

Article

Ptak, Radek^1,2,3  Lazeyras, Francois⁴  Di Pietro, Marie^1,2  Schnider, Armin^1,2  Simon, Stephane R.⁴ 

[1] Univ Hosp Geneva, Dept Clin Neurosci, Div Neurorehabil, Geneva, Switzerland

[2] Univ Geneva, Sch Med, Dept Clin Neurosci, Lab Cognit Neurorehabil, CH-1211 Geneva, Switzerland

[3] Univ Geneva, Fac Psychol & Educ Sci, Geneva, Switzerland

[4] Univ Geneva, Dept Radiol & Med Informat, Geneva, Switzerland

关键词: Object recognition;    Functional MRI;    Lateral occipital cortex;    Visual object agnosia;   

DOI  :  10.1016/j.neuropsychologia.2014.05.009

来源: Elsevier

【 摘 要 】

Patients with visual object agnosia fail to recognize the identity of visually presented objects despite preserved semantic knowledge. Object agnosia may result from damage to visual cortex lying close to or overlapping with the lateral occipital complex (LOC), a brain region that exhibits selectivity to the shape of visually presented objects. Despite this anatomical overlap the relationship between shape processing in the LOC and shape representations in object agnosia is unknown. We studied a patient with object agnosia following isolated damage to the left occipito-temporal cortex overlapping with the LOC. The patient showed intact processing of object structure, yet often made identification errors that were mainly based on the global visual similarity between objects. Using functional Magnetic Resonance Imaging (fMRI) we found that the damaged as well as the contralateral, structurally intact right LOC failed to show any object-selective fMRI activity, though the latter retained selectivity for faces. Thus, unilateral damage to the left LOC led to a bilateral breakdown of neural responses to a specific stimulus class (objects and artefacts) while preserving the response to a different stimulus class (faces). These findings indicate that representations of structure necessary for the identification of objects crucially rely on bilateral, distributed coding of shape features. (C) 2014 Elsevier Ltd. All rights reserved.

【 授权许可】

Free