Size Isn't All that Matters: Noticing Differences in Size and Temporal Order

Area of Science:

• Cognitive Neuroscience
• Neuropsychology
• Brain Imaging

Background:

• The cognitive abilities to perceive time and size are fundamental for action and thought.
• Traditionally, research on temporal and spatial processing has been conducted in isolation.
• Emerging evidence suggests potential anatomical and behavioral overlaps in processing events across time and space.

Purpose of the Study:

• To investigate the associations and dissociations between temporal order judgments (TOJ) and relative size judgments.
• To identify shared and unique neural substrates underlying deficits in TOJ and size perception.
• To explore hemispheric lateralization in the processing of temporal and spatial information.

Main Methods:

• Examined performance on temporal order and relative size judgments in 40 patients with unilateral brain lesions and 20 controls.
• Utilized voxel lesion symptom mapping (VLSM) to correlate lesion location with judgment deficits.
• Analyzed individual patient data to identify double dissociations in performance.

Main Results:

• Brain damage can impair both temporal order and size judgments, but no global hemispheric differences were observed.
• Double dissociations were found, indicating distinct neural underpinnings for each judgment type.
• Shared cortical vulnerabilities for both judgments include the left inferior frontal gyrus, left superior temporal cortex, and bilateral inferior parietal lobule.
• Unique vulnerabilities for TOJ were found in left frontal and parietal regions; unique vulnerabilities for size judgments were in right temporal and parietal regions.

Conclusions:

• Size and temporal order estimations share overlapping cortical vulnerabilities, particularly in the left hemisphere.
• Distinct neural pathways exist for temporal order and size judgments, with specific lateralization for each.
• These findings support the interaction between spatial and temporal processing but do not indicate a right-lateralized system for these functions.