Shape-transitions of a morphing illusory contour can be decoded during multiple-object tracking from the ongoing EEG

Area of Science:

• Cognitive Neuroscience
• Visual Perception

Background:

• Multiple-object tracking (MOT) is a key visual function.
• Previous theories proposed location-based attention for MOT.
• An alternative object-based attention theory suggests tracking an abstract shape configuration.

Purpose of the Study:

• To investigate if object-based attention, specifically an illusory polygon, underlies MOT.
• To examine the neural correlates of topological shape transitions in this polygon using electroencephalography (EEG).

Main Methods:

• Recorded EEG signals from 38 subjects during a multiple-object tracking task.
• Analyzed EEG data for neural signatures corresponding to topological transitions (e.g., convex to concave shape changes, 'flips') of the shortest-path polygon connecting tracked objects.
• Utilized decoding techniques to identify these transition events in the EEG signal.

Main Results:

• Topological transitions of the illusory polygon shape during object motion were successfully decoded from the ongoing EEG signal.
• This demonstrates that the brain represents and processes qualitative changes in the abstract configuration of tracked objects.
• Evidence supports the continuous maintenance and updating of the polygon's shape representation.

Conclusions:

• The findings strongly support an object-based attentional mechanism for multiple-object tracking.
• The visual system actively maintains and updates an abstract object configuration, not just individual item locations.
• EEG decoding of topological transitions provides a neural basis for understanding how abstract spatial relationships are tracked.