Spatiotemporal dynamics of feature-based attention spread: evidence from combined electroencephalographic and magnetoencephalographic recordings.
Attentional selection on the basis of nonspatial stimulus features induces a sensory gain enhancement by increasing the firing-rate of individual neurons tuned to the attended feature, while responses of neurons tuned to opposite feature-values are suppressed. Here we recorded event-related potentials (ERPs) and magnetic fields (ERMFs) in human observers to investigate the underlying neural correlates of feature-based attention at the population level. During the task subjects attended to a moving transparent surface presented in the left visual field, while task-irrelevant probe stimuli executing brief movements into varying directions were presented in the opposite visual field. ERP and ERMF amplitudes elicited by the unattended task-irrelevant probes were modulated as a function of the similarity between their movement direction and the task-relevant movement direction in the attended visual field. These activity modulations reflecting globally enhanced processing of the attended feature were observed to start not before 200 ms poststimulus and were localized to the motion-sensitive area hMT. The current results indicate that feature-based attention operates in a global manner but needs time to spread and provide strong support for the feature-similarity gain model.
Department of Neurology and Center for Advanced Imaging, Otto-von-Guericke-University, 39120 Magdeburg, Germany. christian.stoppel@med.ovgu.de
Christian Michael
CM
Stoppel
Carsten Nicolas
CN
Boehler
Hendrik
H
Strumpf
Ruth Marie
RM
Krebs
Hans-Jochen
HJ
Heinze
Jens-Max
JM
Hopf
Mircea Ariel
MA
Schoenfeld
D000328:Adult; D001288:Attention / Q000502:physiology*; D001921:Brain / Q000502:physiology*; D004569:Electroencephalography; D005074:Evoked Potentials, Visual / Q000502:physiology*; D005260:Female; D006801:Humans; D060526:Magnetic Fields; D015225:Magnetoencephalography; D008297:Male; D009039:Motion Perception / Q000502:physiology*; D017711:Nonlinear Dynamics; D010775:Photic Stimulation; D011930:Reaction Time; D013028:Space Perception / Q000502:physiology*; D013997:Time Factors; D014794:Visual Fields / Q000502:physiology; D055815:Young Adult