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Mehdi Senoussi, Niko Busch, Laurie Galas, Laura Dugué; Comparing the neural dynamics of voluntary feature-based and spatial attention. Journal of Vision 2018;18(10):975. doi: 10.1167/18.10.975.
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© ARVO (1962-2015); The Authors (2016-present)
Voluntary, covert attention, in the absence of eye movement, selectively enhances visual processing. Attention can be directed to a specific location (spatial-based attention, SBA) or stimulus feature (feature-based attention, FBA). Separate experiments have investigated the neural bases underlying each attention system, but none has compared their temporal dynamics using the same task, stimuli and observers. Here, we used EEG to compare the neural dynamics of both feature-based and spatial-based attentional orienting and reorienting. All participants underwent two experimental sessions: one for each attention condition (FBA/SBA). Each session was composed of a 1h-practice followed by the EEG experiment the next day. During practice, observers were trained to associate iconic stimuli (square/diamond) with two possible instructions: attend to either a specific feature (horizontal/vertical grating) or location (left/right quadrant). In the main experiment, observers performed a 2-AFC orientation discrimination task while recording EEG. Trials started with an iconic cue (120ms) instructing observers to attend to a feature or a location. After a 2s-delay, two gratings were presented for 50ms, one on each side of the fixation cross. A response cue simultaneously appeared to indicate the target grating, and observers were asked to report its orientation (grating tilted clockwise/counterclockwise). A trial was valid when the attended stimulus matched the target (75% of trials) and invalid when it did not match (25%). For both FBA and SBA, d-prime was higher in valid than invalid trials, confirming that iconic cues can successfully manipulate either type of attention. Moreover, we replicated previous results according to which alpha oscillations (~10Hz) lateralize during the preparation interval (between cue and stimuli) in SBA, but not in FBA. Finally, using classification techniques we identified the neural signature of FBA and SBA using the same task, stimuli and observers. This experiment furthers our understanding of the neural bases underlying both attention systems.
Meeting abstract presented at VSS 2018
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