Comparison of fMRI paradigms assessing visuospatial processing: Robustness and reproducibility

PLoS One. 2017 Oct 23;12(10):e0186344. doi: 10.1371/journal.pone.0186344. eCollection 2017.

Abstract

The development of brain imaging techniques, in particular functional magnetic resonance imaging (fMRI), made it possible to non-invasively study the hemispheric lateralization of cognitive brain functions in large cohorts. Comprehensive models of hemispheric lateralization are, however, still missing and should not only account for the hemispheric specialization of individual brain functions, but also for the interactions among different lateralized cognitive processes (e.g., language and visuospatial processing). This calls for robust and reliable paradigms to study hemispheric lateralization for various cognitive functions. While numerous reliable imaging paradigms have been developed for language, which represents the most prominent left-lateralized brain function, the reliability of imaging paradigms investigating typically right-lateralized brain functions, such as visuospatial processing, has received comparatively less attention. In the present study, we aimed to establish an fMRI paradigm that robustly and reliably identifies right-hemispheric activation evoked by visuospatial processing in individual subjects. In a first study, we therefore compared three frequently used paradigms for assessing visuospatial processing and evaluated their utility to robustly detect right-lateralized brain activity on a single-subject level. In a second study, we then assessed the test-retest reliability of the so-called Landmark task-the paradigm that yielded the most robust results in study 1. At the single-voxel level, we found poor reliability of the brain activation underlying visuospatial attention. This suggests that poor signal-to-noise ratios can become a limiting factor for test-retest reliability. This represents a common detriment of fMRI paradigms investigating visuospatial attention in general and therefore highlights the need for careful considerations of both the possibilities and limitations of the respective fMRI paradigm-in particular, when being interested in effects at the single-voxel level. Notably, however, when focusing on the reliability of measures of hemispheric lateralization (which was the main goal of study 2), we show that hemispheric dominance (quantified by the lateralization index, LI, with |LI| >0.4) of the evoked activation could be robustly determined in more than 62% and, if considering only two categories (i.e., left, right), in more than 93% of our subjects. Furthermore, the reliability of the lateralization strength (LI) was "fair" to "good". In conclusion, our results suggest that the degree of right-hemispheric dominance during visuospatial processing can be reliably determined using the Landmark task, both at the group and single-subject level, while at the same time stressing the need for future refinements of experimental paradigms and more sophisticated fMRI data acquisition techniques.

Publication types

  • Comparative Study

MeSH terms

  • Adult
  • Female
  • Humans
  • Magnetic Resonance Imaging / methods*
  • Male
  • Photic Stimulation*
  • Reproducibility of Results
  • Task Performance and Analysis
  • Young Adult

Grants and funding

This work was supported by the Research Foundation of the Philipps-University Marburg, the ETH Zurich Postdoctoral Fellowship Program and the Marie Curie Actions for People COFUND Program (to SF) as well as the Else Kröner-Fresenius Stiftung (grant 2012_A219) (to AJ and SW), the Förder- und Innovationspool der RHÖN KLINIKUM AG (grant FI60) and the von-Behring-Röntgen-Stiftung (grant63-0030) (both to AJ and KMZ).