Fractionation of parietal function in bistable perception probed with concurrent TMS-EEG

Area of Science:

• Cognitive Neuroscience
• Neuroimaging
• Perception

Background:

• Bistable perception involves spontaneous alternations in conscious awareness between conflicting visual interpretations.
• Previous studies implicate two right parietal areas (anterior and posterior superior parietal lobule – SPLr) in resolving perceptual ambiguity.
• Prior transcranial magnetic stimulation (TMS) research suggests these regions have opposing roles in perceptual switching.

Purpose of the Study:

• To investigate the functional fractionation of the right parietal cortex in bistable perception.
• To elucidate the causal role of specific parietal subregions in resolving perceptual ambiguity.
• To examine the temporal dynamics of parietal involvement during perceptual switches.

Main Methods:

• Combined TMS with electroencephalography (EEG) to precisely interfere with and record neural activity.
• Applied single-pulse TMS to anterior and posterior SPLr independently in participants viewing bistable stimuli.
• Utilized individual structural MRI scans for accurate targeting and analysis of TMS effects on EEG time series.

Main Results:

• The study generated a rich dataset combining TMS, EEG, and fMRI for complex neural analyses.
• Analysis focused on the causal impact of stimulating distinct parietal regions on neural activity.
• Results are expected to reveal the specific contributions of ant-SPLr and post-SPLr to perceptual alternations.

Conclusions:

• The combined TMS-EEG approach offers enhanced causal insights into parietal cortex function during ambiguous perception.
• Findings will clarify the distinct roles of right parietal subregions in mediating conscious perceptual switches.
• This research advances our understanding of the neural mechanisms underlying perceptual ambiguity resolution.