Imaging the brain activity changes underlying impaired visuospatial judgments: simultaneous FMRI, TMS, and behavioral...

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Brain Imaging

Background:

• Parietal cortex damage impairs visuospatial judgment.
• The impact of parietal damage on remote, interconnected brain regions remains unclear.
• Understanding network dynamics is crucial for explaining cognitive deficits.

Purpose of the Study:

• To investigate the behavioral and neural effects of transient parietal cortex disruption on visuospatial judgments.
• To identify remote brain regions functionally affected by parietal stimulation.
• To explore the network mechanisms underlying visuospatial processing and deficits.

Main Methods:

• Transcranial magnetic stimulation (TMS) applied to parietal cortices during functional magnetic resonance imaging (fMRI).
• Participants performed visuospatial tasks while undergoing concurrent TMS and fMRI.
• Behavioral performance and neural activity changes were measured.

Main Results:

• Right parietal TMS, but not left, significantly impaired visuospatial judgment.
• TMS induced neural activity changes in a right-hemispheric frontoparietal network.
• Correlations were found between behavioral deficits and neural activity changes in parietal and frontal regions.

Conclusions:

• Visuospatial deficits after parietal damage result from network perturbation, not just the lesioned site.
• A specific right-hemispheric frontoparietal network is critical for visuospatial judgments.
• Concurrent TMS-fMRI during tasks effectively visualizes functionally connected brain networks.