Attention to color: an analysis of selection, controlled search, and motor activation, using event-related potentials.
In this study the organization of information processing in a selective search task was examined by analyzing event-related potentials. This task consisted of searching for target letters in a relevant (attended) color. The ERPs revealed two different effects of attention: an early occipital negativity (+/- 150 ms) reflecting feature-specific attention, and a later, central N2b component (+/- 240 ms) reflecting covert orienting of attention. A later, prolonged negativity (search-related negativity) (+/- 300 ms), maximal at Cz, was related to controlled search to letters in the attended color. Detection of relevant targets resulted in a parietal P3b component. Depending on stimulus presentation conditions an earlier response to both attended and unattended targets was found: an N2 component (+/- 250 ms). In these same conditions, C'3-C'4 asymmetries (Corrected Motor Asymmetries--CMA) suggested motor activation at +/- 300 ms, in the same time range as search-related negativity. It was argued that N2 and CMA suggest the existence of a preattentive target detection system, operating in parallel with a slower serial attentive system, as reflected by N2b and search negativity.
Wijers
A A
AA
Mulder
G
G
Okita
T
T
Mulder
L J
LJ
Scheffers
M K
MK
D000328:Adult; D001143:Arousal; D001288:Attention; D003118:Color Perception; D005260:Female; D005556:Form Perception; D006801:Humans; D008297:Male; D011939:Mental Recall; D009949:Orientation; D010364:Pattern Recognition, Visual; D011597:Psychomotor Performance