Visuo-spatial attention influences the rate of evidence accumulation during perceptual decision making
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1
Trinity College Dublin, Neural Engineering, Ireland
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2
Monash University, Australia
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3
Trinity College Dublin, Neural Engineering, Ireland
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4
City College of New York, United States of America
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5
Trinity College Dublin, Trinity College Institute of Neuroscience, Ireland
A theoretical "decision variable" has been posited to account for humans' ability to make behaviourally-relevant decisions based on weak or ambiguous perceptual input from the environment. Recently a neural signal, the Centroparietal Positive Potential (CPP), has been observed in human EEG which exhibits two key properties of such a decision variable, i.e. a buildup rate which scales with sensory evidence and a threshold amplitude which is reached at the point of perceptual report. Discovery of this signal in humans allows the direct investigation of influences on decision making, one of which is spatial attention. The purpose of this study was to examine the impact of spontaneous pre-target attentional fluctuations on the properties of the CPP within a spatial attention paradigm.
In an uncued gradual target detection paradigm, participants monitored two patches of randomly moving dots, one in either visual hemifield, for coherent motion targets. Hemispheric lateralization of parieto-occipital ?-band activity in the pre-target period was used as an index of the relative distribution of spatial attention resources to each hemi-field. We found that ?-lateralization was predictive of reaction times (RTs) to targets at the single-trial level, such that a relative decrease in contralateral ?-power was associated with faster RTs. Analysis of the CPP revealed that diminished contralateral ?-power was specifically associated with a faster rate of perceptual evidence accumulation.
These results extend findings of the effect of lateralization of pre-target ?-power on post-target speed of processing, indicating that this method can be used as a measure of spontaneous fluctuations of spatial attention. Furthermore, the rate of post-target evidence accumulation was influenced by these variations in ?-lateralization, revealing a link between attentional processes and a specific aspect of decision-making, i.e. speed of evidence accumulation.
Keywords:
Decision Making,
EEG,
spatial attention,
alpha,
pseudoneglect
Conference:
XII International Conference on Cognitive Neuroscience (ICON-XII), Brisbane, Queensland, Australia, 27 Jul - 31 Jul, 2014.
Presentation Type:
Poster
Topic:
Attention
Citation:
Loughnane
G,
Newman
D,
Bellgrove
M,
Lalor
E,
Kelly
S and
O'Connell
R
(2015). Visuo-spatial attention influences the rate of evidence accumulation during perceptual decision making.
Conference Abstract:
XII International Conference on Cognitive Neuroscience (ICON-XII).
doi: 10.3389/conf.fnhum.2015.217.00216
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Received:
19 Feb 2015;
Published Online:
24 Apr 2015.
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Correspondence:
Mr. Gerard Loughnane, Trinity College Dublin, Neural Engineering, Dublin, Ireland, gerontium@gmail.com