Parietal cortex mediates conscious perception of illusory gestalt
Natalia Zaretskaya1, Stuart Anstis, Andreas Bartels
1Vision and Cognition Laboratory, Centre for Integrative Neuroscience, University of Tübingen, D-72076 Tübingen, Germany.
Summary
The anterior intraparietal sulcus (aIPS) is crucial for spatial binding, enabling the brain to perceive grouped visual elements as a holistic Gestalt. Disrupting aIPS selectively shortens the conscious experience of these global Gestalt perceptions.
Area of Science:
- Neuroscience
- Cognitive Psychology
- Visual Perception
Background:
- Spatial binding, or grouping local elements into a holistic percept, is essential for meaningful perception.
- While early visual areas (V1, V2) show grouping signals, higher-level processes for global Gestalt perception are less understood.
Purpose of the Study:
- To investigate the neural mechanisms underlying global Gestalt perception and spatial binding.
- To identify higher-level brain regions involved in integrating local visual elements into a unified percept.
Main Methods:
- Utilized a novel bistable motion illusion to create alternating conscious perceptions of illusory contours (global Gestalt) versus ungrouped local elements.
- Employed functional magnetic resonance imaging (fMRI) to observe brain activity during these perceptual shifts.
- Applied transcranial magnetic stimulation (TMS) to disrupt activity in specific parietal cortex regions.
Main Results:
- fMRI revealed that activity fluctuations in the superior parietal lobe and anterior intraparietal sulcus (aIPS) correlated with the perception of the global Gestalt.
- TMS applied to the aIPS selectively shortened the duration of the global Gestalt percept.
- No significant effect on the perception of ungrouped local elements was observed with aIPS TMS.
Conclusions:
- Anterior intraparietal sulcus (aIPS) activity is directly implicated in the process of spatial binding during visual perception.
- Conscious perception of global Gestalt relies on aIPS function, akin to its roles in attention and perceptual selection.
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