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Revisiting the Landmark Task as a tool for studying hemispheric specialization: What's really right?
Anna Seydell-Greenwald1, Serena F Pu1, Katrina Ferrara2
1Center for Brain Plasticity and Recovery, Georgetown University, Building D, Suite 145, 4000 Reservoir Road NW, Washington, D.C. 20057, USA.
Neuropsychologia
|February 26, 2019
Summary
The Landmark Task (LT), a line bisection judgment, consistently activates the right parietal cortex. This right-lateralized brain activation persists even with vertical lines and varying difficulty, suggesting unique task properties.
Area of Science:
- Neuroscience
- Cognitive Psychology
- Neuroimaging
Background:
- The Landmark Task (LT) typically involves judging horizontal line bisections, activating the right parietal cortex.
- This task may involve spatial attention and representation, with the right hemisphere being crucial for spatial attention.
Purpose of the Study:
- To investigate if Landmark Task (LT) activation remains right-lateralized irrespective of spatial attention demands.
- To examine the effect of task difficulty on the lateralization of Landmark Task (LT) activation.
Main Methods:
- Functional magnetic resonance imaging (fMRI) was used to study 26 healthy adults.
- Participants performed the Landmark Task (LT) with vertical stimuli and a luminance control task, with varying difficulty levels.
Main Results:
- Consistent right-lateralized parietal activations were observed for the Landmark Task (LT) at both group and individual levels.
- These findings held true despite using vertical stimuli and manipulating task difficulty, suggesting robust lateralization.
Conclusions:
- The Landmark Task (LT) demonstrates robust right-lateralized parietal activation, potentially unique among spatial tasks.
- This unique lateralization may stem from the task's requirement to judge relative line segment magnitudes, rather than general spatial attention or representation.