Spatio-temporal dynamics of attentional selection stages during multiple object tracking.
Subjects can visually track several moving items simultaneously, a fact that is difficult to explain by classical attention models. Previous work revealed that building a global shape based on the spatial position of the tracked items improves performance. Here we investigated the involved neural processes and the role of attention. A task-irrelevant probe stimulus was presented during multiple objects tracking at a fixed spatial location. Depending on the tracked item's trajectories the probe appeared either outside, inside, or on the edge of aforementioned global shape. Event-related potentials to the probe stimulus revealed two subsequent stages of attentional selection during multiple object tracking. After 100ms attention was deployed on the edge/boundary of the figure formed by the tracked items. In the following 80ms, attention spread from the outline to the full figure. These findings clarify the eminent contribution of attentional mechanisms in multiple objects tracking.
Department of Neurology, Otto-von-Guericke University, Magdeburg, Germany. Electronic address: christian.merkel@med.ovgu.de.
Christian
C
Merkel
Department of Neurology, Otto-von-Guericke University, Magdeburg, Germany; Department of Behavioral Neurology, Leibniz-Institute for Neurobiology, Magdeburg, Germany.
Jens-Max
JM
Hopf
Department of Neurology, Otto-von-Guericke University, Magdeburg, Germany; Department of Behavioral Neurology, Leibniz-Institute for Neurobiology, Magdeburg, Germany; Kliniken Schmieder Heidelberg, Heidelberg, Germany.
Mircea Ariel
MA
Schoenfeld
D000328:Adult; D001288:Attention / Q000502:physiology*; D005071:Evoked Potentials; D053483:Eye Movement Measurements; D005260:Female; D006801:Humans; D015225:Magnetoencephalography; D008297:Male; D009039:Motion Perception / Q000502:physiology*; D010775:Photic Stimulation; D011930:Reaction Time; D013028:Space Perception / Q000502:physiology*
Event-related potentials; Multiple object tracking; Object-based attention