Exploratory data analysis reveals visuovisual interhemispheric transfer in functional magnetic resonance imaging

Abstract

We used an exploratory data analysis approach to detect interhemispheric processing of complex visual stimuli in functional magnetic resonance imaging (fMRI). A crossed-uncrossed visual field paradigm was used to elicit interhemispheric transfer of picture/word information. Under the uncrossed (control) condition, the stimuli were presented to the preferential hemispheres (pictures to the left visual field/right hemisphere and words to the right visual field/left hemisphere). Under the crossed condition, the visual field presentation was switched in order to elicit increased interhemispheric processing. Fuzzy cluster analysis revealed significantly more crossed activity in cortical areas near the splenium of the corpus callosum. As expected, examination of the activation revealed smaller responses in perisplenial regions (relative to visual responses in the medial extrastriate regions). The exploratory results were compared with those obtained from parametric and masked analyses. The findings confirm that fMRI can be used to detect interhemispheric transfer of picture/word information. The activation was optimally characterized using exploratory data analysis. Magn Reson Med 55:952-958, 2006.

Functional mapping in the corpus callosum: A 4T fMRI study of white matter

“…The Poffenberger task was completed with a mean accuracy of 97.5%. 3 The mean reaction time of the motor cross condition (413.9 ms, SD = 73.8 ms) was longer than the mean reaction time in the uncrossed condition (351.7 ms, SD = 53.6 ms). The mean crossed-uncrossed difference was 62.2 ms, which was statistically significant (p < 0.001).…”

Comparing gray and white matter fMRI activation using asymmetric spin echo spiral

“…In spite of the bias against it, a growing body of evidence supports fMRI in WM regions (Omura et al, 2004;Weber et al, 2005;D'Arcy et al, 2006;Mazerolle et al, 2008;Gawryluk et al, 2009Gawryluk et al, , 2011Yarkoni et al, 2009;Mazerolle et al, 2010;Fabri et al, 2011). Recent findings can be attributed to known energy-dependent processes in WM (Tettamanti et al, 2002;Mazerolle et al, 2008).…”

“…In order to elicit WM activation, many studies have examined interhemispheric transfer (IHT) across the corpus callosum (e.g., D'Arcy et al, 2006;Mazerolle et al, 2008). Tasks typically involve rapid presentation of stimuli to a visual field, with contralateral motor responses.…”

Confirming white matter fMRI activation in the corpus callosum: Co-localization with DTI tractography

“…Such tasks, in which functionally lateralized stimuli (words and faces) are presented to the right and left visual hemifields, have been used to study disconnection syndromes in split brain patients (Gazzaniga, Bogen, and Sperry, 1965) and have been previously developed for fMRI (D'Arcy et al, 2006). Mazerolle et al (2008) reported activation in the isthmus of the corpus callosum in 21% of individuals.…”