Project Details
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Shifting attention within or between feature dimensions. Neural temporal dynamics in human early visual cortex

Subject Area General, Cognitive and Mathematical Psychology
Human Cognitive and Systems Neuroscience
Term from 2016 to 2023
Project identifier Deutsche Forschungsgemeinschaft (DFG) - Project number 317885770
 
Final Report Year 2023

Final Report Abstract

The project aimed to shed light on two major questions: (a) what are the temporal neural dynamics of top-down modulated shifts between or across feature dimensions (color vs. orientation) in feature-based attention (FBA), and (b) what are the cortical sources of the steady state visual evoked potentials (SSVEPs) amplitude modulations with FBA and spatial attention? To this end we presented frequency-tagged stimuli to evoke SSVEPs in either an EEG, MEG or combined EEG/fMRT environment. With regard to the first research question, we found fast facilitation of SSVEP amplitudes after the cue for shifts toward color, regardless of the origin (color or orientation). Rapid facilitation of the newly to-be-attended feature was followed by slower inhibition/suppression of the then to-be-ignored feature. Shifts between dimensions had a longer latency for inhibition/suppression of SSVEP amplitudes compared to shifts from one color to the other. Regarding the second research question, we found that cortical sources of attentional SSVEP amplitude modulations were specific to the processing of an attended feature, i.e. V4 when subjects attended to color or V1 when they attended to shape, while areas V5/hMT+ exhibited an unspecific BOLD enhancement, regardless of what feature needed to be attended. Cortical sources for spatial attention effects were also restricted to early visual cortex: V1, V2, hMT+, precuneus, occipital-parietal and inferior-temporal cortex.

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