Key result
Distinct right parieto-frontal and temporo-occipital disconnections map to specific spatial body-orientation deficits after stroke.
Why the study?
The neural substrates underlying egocentric spatial reference frame impairments after right-hemisphere stroke, particularly in terms of structural connectivity, are poorly understood.
Cross-Sectional (n=57)
Blind lesion segmentation by a neuroimaging-trained physician
Yes
Answers are grounded in this paper and cite their sources.
Demonstrates that post-stroke impairments in subjective straight ahead and longitudinal body axis perception rely on partially dissociable cortical and white matter networks, supporting combined assessment to tailor spatial rehabilitation after right-hemisphere stroke.
Spatial cognition impairments have been shown to reduce autonomy, partly due to alterations in the egocentric spatial reference frame. However, little is known about the neural substrates underlying these impairments, particularly in terms of structural connectivity. We aimed to investigate the neural bases of two complementary components of the egocentric spatial reference frame by analysing both lesion locations and probabilities of white matter disconnection. Fifty-seven individuals with right-hemispheric strokes were included. Egocentric spatial representation was assessed using the subjective straight ahead (SSA) and the longitudinal body axis (LBA). Voxel-based lesion-symptom mapping and disconnectome analyses using BCBtoolkit were performed to study the relationship between SSA and LBA misperceptions, lesion location, and probabilities of white matter disconnection. SSA and LBA misperceptions were associated with partially dissociable neural patterns. SSA misperception was mainly associated with right parieto-frontal lesions and with an exploratory association involving the posterior corpus callosum. In contrast, LBA misperception was associated with right temporo-occipital lesions and disconnections involving the right inferior longitudinal fasciculus, right cingulum fasciculus, posterior corpus callosum, and right inferior fronto-occipital fasciculus. These exploratory findings suggest that SSA and LBA misperceptions, although assessed in the same egocentric reference system, rely on distinct neural substrates. SSA may place greater demands on action-oriented spatial processing in extracorporeal space, whereas LBA may rely more strongly on cross-modal integration between an internal body-centred representation of the longitudinal body axis and a visual cue. Assessing both tasks may help improve the characterisation and rehabilitation of spatial cognition impairments after right-hemisphere stroke. Trial Registration Number and Date of Registration: The original study was approved by the Institutional Review Board of Poitiers-France III West No. 051216. The trial was registered before first inclusion (NCT01677091).
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Painchaud et al. (2026) conducted a cross-sectional in Right-hemisphere stroke with left hemiparesis and spatial cognition impairment (n=57). Right-hemisphere brain lesion location and white matter disconnection probability was evaluated on Mean absolute angular deviation error on subjective straight ahead (SSA) and longitudinal body axis (LBA) tasks mapped to brain lesions and white matter tract disconnections (p=0.003). Subjective straight ahead misperception associated with right parieto-frontal lesions, while longitudinal body axis misperception linked to temporo-occipital and ILF disconnections.
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