Unconscious processing of visual saliency

1. Unconscious processing of visual saliency Ryota Kanai, Vincent Walsh Institute of Cognitive Neuroscience and Department of Psychology University College London

2. The goal: disentangle functions of attention areas (FEF and IPS) Motivation: Attention related areas show similar responses to attentional tasks. We would like to know how FEF and IPS play functionally distinct roles. 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.

3. How do we tackle the problem? 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. Right Eye Left Eye + + The goal is to see lateralized responses to the pop-out target in FEF and IPS

4. Proposed fMRI study Conditions to compare: Target in left visual field Target in right visual field Target absent Event-related design e.g.) 6min scan (45 trials) x 4 visible + 4 invisible runs LV abs RV LV Each stimulus 3 sec Inter trial interval: 3~8 sec