Download Difficulty (part of the hypothesis)

Unconscious processing of visual saliency
Ryota Kanai, Vincent Walsh
Institute of Cognitive Neuroscience and Department of Psychology
University College London
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.
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.
Left Eye
+
Right Eye
QuickTi me™ and a
T IFF (P ackB i ts) decom pressor
are needed to see t his pict ure.
+
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 absent
Target in right visual field
Event-related design
e.g.)
LV
abs
Each stimulus 3 sec
Inter trial interval: 3~8 sec
RV
LV
6min scan (45 trials)
x
4 visible + 4 invisible runs