David Linhardt¹, Dominik Zuschlag¹, Adam Coates^2,3, Natalia Zaretskaya^2,3, Christian Windischberger¹; ¹Medical University of Vienna, Austria, ²University of Graz, Austria, ³BioTechMed-Graz, Austria

The claustrum is an interconnected sheet-like subcortical structure with a potentially important role in sensory integration and attention. Recent work provided the first fMRI evidence of a visual zone within the human claustrum (Coates et al., 2024). Structural connectivity studies have further demonstrated white matter pathways linking the claustrum to the ipsilateral visual cortex in both sheep (Pirone et al., 2021) and humans (Milardi et al., 2015), suggesting its importance in sensory processing. Since the visual cortex of one hemisphere contains a representation of the contralateral hemifield, this suggests that a similar functional organization may exist in the visual claustrum zone. To investigate this, we analyzed data from the Human Connectome Project retinotopy dataset (Benson et al., 2018). Using fMRI data collected from 181 participants during visual stimulation, we designed two orthogonal regressors corresponding to periods when a wedge stimulus traversed the left or the right visual hemifield. These regressors were applied within a general linear model (GLM) to analyze BOLD signals in the claustrum and early visual cortex. This allowed us to probe the lateralization of visual responses. Our results reveal a lateralized activation pattern: the claustrum in each hemisphere shows activation together with its ipsilateral visual cortex during contralateral visual field stimulation. This organization mirrors the cortical contralateral representation of visual space and provides the first evidence of functional lateralization in the human claustrum’s visual zone. These findings highlight the claustrum’s potential role in hemifield-specific visual processing.

Acknowledgements: This research was funded in whole or in part by the Austrian Science Fund (FWF) [10.55776/P35583; 10.55776/PAT8722623]. AC and NZ were supported by the BioTechMed-Graz Young Researcher Group Grant.