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Original Research ARTICLE

Spatial selection of features within perceived and remembered objects

Duncan E. Astle^*, Gaia Scerif, Bo-Cheng Kuo and Anna C. Nobre

University of Oxford, Oxford, UK

Our representation of the visual world can be modulated by spatially specific attentional biases that depend flexibly on task goals. We compared searching for task-relevant features in perceived versus remembered objects. When searching perceptual input, selected task-relevant and suppressed task-irrelevant features elicited contrasting spatiotopic ERP effects, despite them being perceptually identical. This was also true when participants searched a memory array, suggesting that memory had retained the spatial organization of the original perceptual input and that this representation could be modulated in a spatially specific fashion. However, task-relevant selection and task-irrelevant suppression effects were of the opposite polarity when searching remembered compared to perceived objects. We suggest that this surprising result stems from the nature of feature- and object-based representations when stored in visual short-term memory. When stored, features are integrated into objects, meaning that the spatially specific selection mechanisms must operate upon objects rather than specific feature-level representations.

Keywords:

spatial attention, visual short-term memory, working memory, ERPs, electrophysiology, task-set control

Citation:

Astle DE, Scerif G, Kuo B-C and Nobre AC (2009). Spatial selection of features within perceived and remembered objects. Front. Hum. Neurosci. 3:6. doi: 10.3389/neuro.09.006.2009

Received:

04 February 2009;

Paper pending published:

16 February 2009;

Accepted:

07 April 2009;

Published online:

27 April 2009.

Edited by:

George R. Mangun, University of California Davis, USA

Reviewed by:

Mircea A. Schoenfeld, Otto-von-Guericke University, Germany
Robert T. Knight, University of California Berkeley, USA

© 2009 Astle, Scerif, Kuo and Nobre. This is an open-access article subject to an exclusive license agreement between the authors and the Frontiers Research Foundation, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are credited.

*Correspondence:

Duncan Astle, Department of Experimental Psychology, University of Oxford, South Parks Road, Oxford OX1 3UD, UK. e-mail: duncan.astle@psy.ox.ac.uk