Unconscious processing of visual saliency
Ryota Kanai, Vincent Walsh
Institute of Cognitive Neuroscience and Department of Psychology
University College London
Motivation:Attention related areas show similar responses to attentional tasks.We would like to know how FEF and IPS play functionally distinct roles.
The goal: disentangle functions of attention areas (FEF and IPS)
Hypothesis:IPS is involved in bottom-up saliency computation, and FEF is involved in forming task set (template).
Difficulty (part of the hypothesis):Task set is also triggered by bottom-up events. So FEF appears to be stimulus driven (e.g. responses to saliency). So usually FEF and IPS behave in a similar way.
How do we tackle the problem?
Left Eye Right Eye
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We look at cortical responses to two types of attention capturing stimuli outside awareness.
1. Present an array of stimuli with a pop-out target to the suppressed eye.
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The goal is to see lateralized responses to the pop-out target in FEF and IPS
Proposed fMRI study
Conditions to compare:
Target in left visual field Target in right visual field
Target absent Event-related design
Each stimulus 3 sec
e.g.)
Inter trial interval: 3~8 sec
LV abs RV LV 6min scan (45 trials)x
4 visible + 4 invisible runs
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