Accelerated and amplified neural responses in visual discrimination: Two features are processed faster than one

• Published in: NeuroImage (Orlando, Fla.) Vol. 26; no. 4; pp. 986 - 995
• Main Authors: Lobaugh, Nancy J., Chevalier, Hélène, Batty, Magali, Taylor, Margot J.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 15.07.2005; Elsevier Limited; Elsevier
• Subjects: Adult; Attention; Attention - physiology; Binding; Brain; Brain - physiology; Color Perception; Color Perception - physiology; Conjunctions; Discrimination; Discrimination (Psychology); Discrimination (Psychology) - physiology; Electroencephalography; Electrooculography; ERPs; Evoked Potentials; Evoked Potentials - physiology; Facilitation; Features; Female; Form Perception; Form Perception - physiology; Humans; Life Sciences; Male; Medical research; Middle Aged; Multivariate Analysis; Neurons and Cognition; Partial least squares; Photic Stimulation; Psychomotor Performance; Psychomotor Performance - physiology; Reaction Time - physiology; Studies; Visual attention; Visual Perception - physiology; Visual task performance; Facilitation; Binding; ERPs; Features; Conjunctions; Multivariate analysis; Visual attention; Partial least squares
• ISSN: 1053-8119; 1095-9572
• DOI: 10.1016/j.neuroimage.2005.03.007

Psychological and neurophysiological models of visual processing have traditionally emphasized hierarchical models to explain how separate features of visual stimuli are combined. This concept has been challenged recently with the demonstration of simultaneous activation of multiple visual areas and rapid feedback to primary cortices. Here, we show human visual processing may involve similar mechanisms. Subjects discriminated targets from nontargets as a function of shape, color, or the conjunction of these features while event-related brain potentials (ERPs) were recorded. ERP components from 100 to 200 ms across posterior occipital–temporal cortices were fastest and largest for conjunction targets. These enhanced early responses were followed by task-specific sustained posterior activity (300–500 ms). Faster reaction times were correlated with enhanced and faster early processing in the visual ventral areas. These data demonstrate the human visual system conjoins features rapidly, accelerating and amplifying the processing of relevant stimulus dimensions.