Orientation pop-out processing in human visual cortex

• Published in: NeuroImage (Orlando, Fla.) Fla.), 2013-11, Vol.81, p.73-80
• Main Authors: Bogler, Carsten, Bode, Stefan, Haynes, John-Dylan
• Format: Article
• Language: English
• Subjects: Adult; Biological and medical sciences; Brain; Brain Mapping; Experiments; Eye and associated structures. Visual pathways and centers. Vision; Female; Functional MRI; Fundamental and applied biological sciences. Psychology; Humans; Image Processing, Computer-Assisted; Magnetic Resonance Imaging; Male; Neurons; Orientation - physiology; Pop-out; Reaction Time - physiology; Studies; Vertebrates: nervous system and sense organs; Visual attention; Visual cortex; Visual Cortex - physiology; Visual Perception - physiology; Young Adult
• ISSN: 1053-8119; 1095-9572
• DOI: 10.1016/j.neuroimage.2013.05.040

Visual stimuli can “pop out” if they are different to their background. There has been considerable debate as to the role of primary visual cortex (V1) versus higher visual areas (esp. V4) in pop-out processing. Here we parametrically modulated the relative orientation of stimuli and their backgrounds to investigate the neural correlates of pop-out in visual cortex while subjects were performing a demanding fixation task in a scanner. Whole brain and region of interest analyses confirmed a representation of orientation contrast in extrastriate visual cortex (V4), but not in striate visual cortex (V1). Thus, although previous studies have shown that human V1 can be involved in orientation pop-out, our findings demonstrate that there are cases where V1 is “blind” and pop-out detection is restricted to higher visual areas. Pop-out processing is presumably a distributed process across multiple visual regions. •Orientation pop-out is encoded in extrastriate visual cortex (V4).•There are cases where pop-out detection is restricted to higher visual areas.•The results speak for a distributed processing of pop-out in visual cortex.