June 2007
Volume 7, Issue 9
Free
Vision Sciences Society Annual Meeting Abstract  |   June 2007
Parietal lesion leading to hemineglect and reduced extrastriate activity in a computational model of visual attention
Author Affiliations
  • Linda Lanyon
    Human Vision & Eye Movement Laboratory, University of British Columbia
  • Susan Denham
    Centre for Theoretical & Computational Neuroscience, University of Plymouth
Journal of Vision June 2007, Vol.7, 952. doi:10.1167/7.9.952
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      Linda Lanyon, Susan Denham; Parietal lesion leading to hemineglect and reduced extrastriate activity in a computational model of visual attention. Journal of Vision 2007;7(9):952. doi: 10.1167/7.9.952.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

A neurophysiological computational model of visual attention [1] shows how replication of spatial and object-based attentional effects at the cellular level can lead to systems level performance that mimics search scan path behavior found in humans and monkeys [2]. Here we show how lesion of this model's parietal cortex leads to symptoms of visual neglect similar to that found in search scan paths produced by parietal patients with hemineglect [3]. Scan paths produced by the lesioned model are attracted to the ipsilateral hemifield of the search display and ignore stimuli present in the contralesional hemifield. Similar to patients [3], the lesioned model tends to re-fixate locations in the scan path more often. Lesion of the orbitofrontal portion of the model also increases re-fixation rates. During parietal lesion simulations, activity is also modulated within the ipsilesional extrastriate area (V4) of the model's ventral visual stream, despite this area being intact. This offers explanation of neuroimaging results showing increased activity in extrastriate cortex when stimuli are consciously perceived by parietal patients compared to when these stimuli do not enter conscious awareness [4].

[1]. L. J. Lanyon and S.L. (2004). Neural Networks: Special Issue: Vision & Brain, 17(5-6), 873-897

[2]. B. Motter and E. J. Belky. (1998). Vision Research, 38(12), 1805-1815

[3]. M. Husain, S. Mannan, T. Hodgson, E. Wojciulik, J. Driver, and C. Kennard. (2001). Brain, 124, 941-952

[4]. J. Driver, P. Vuilleumier, M. Eimer, and G. Rees. (2001). Neuroimage, 14, S68-S75.

Lanyon, L. Denham, S. (2007). Parietal lesion leading to hemineglect and reduced extrastriate activity in a computational model of visual attention [Abstract]. Journal of Vision, 7(9):952, 952a, http://journalofvision.org/7/9/952/, doi:10.1167/7.9.952. [CrossRef]
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