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bioRxiv · 10.1101/414508

Endogenous and exogenous attention distinctly modulate fMRI activity in visual cortex

Dugue, L.·Merriam, E. P.·Heeger, D. J.·Carrasco, M.
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Abstract

How do endogenous (voluntary) and exogenous (involuntary) attention modulate activity in visual cortex? Using ROI-based fMRI analysis, we measured fMRI activity for valid and invalid trials (target at cued/un-cued location, respectively), pre- or post-cueing endogenous or exogenous attention, while participants performed the same orientation discrimination task. We found stronger modulation in contralateral than ipsilateral visual regions, and higher activity in valid-than invalid-trials. For endogenous attention, modulation of stimulus-evoked activity due to a pre-cue increased along the visual hierarchy, but was constant due to a post-cue. For exogenous attention, modulation of stimulus-evoked activity due to a pre-cue was constant along the visual hierarchy, but was not modulated due to a post-cue. These findings reveal that endogenous and exogenous attention distinctly modulate activity in visuo-occipital areas during orienting and reorienting; endogenous attention facilitates both the encoding and the readout of visual information whereas exogenous attention only facilitates the encoding of information.

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Dugue, L., Merriam, E. P., Heeger, D. J., Carrasco, M.. 2018-09-11. Endogenous and exogenous attention distinctly modulate fMRI activity in visual cortex. https://doi.org/10.1101/414508

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