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 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. + + 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 fieldTarget in right visual field Target absent Event-related design Each stimulus 3 sec e.g.) Inter trial interval: 3~8 sec LV absRVLV 6min scan (45 trials) x 4 visible + 4 invisible runs