Open AccessDirect comparison of activation maps during galvanic vestibular stimulation: A hybrid H2[15 O] PET—BOLD MRI activation study
Author(s) -
Sandra BeckerBense,
Frode Willoch,
Thomas Stephan,
Matthias Brendel,
Igor Yakushev,
M. Habs,
Sibylle Ziegler,
Michael Herz,
Markus Schwaiger,
Marianne Dieterich,
Peter Bartenstein
Publication year - 2020
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0233262
Subject(s) - galvanic vestibular stimulation , statistical parametric mapping , vestibular system , psychology , nuclear medicine , visual cortex , functional magnetic resonance imaging , medicine , neuroscience , magnetic resonance imaging , radiology
Previous unimodal PET and fMRI studies in humans revealed a reproducible vestibular brain activation pattern, but with variations in its weighting and expansiveness. Hybrid studies minimizing methodological variations at baseline conditions are rare and still lacking for task-based designs. Thus, we applied for the first time hybrid 3T PET-MRI scanning (Siemens mMR) in healthy volunteers using galvanic vestibular stimulation (GVS) in healthy volunteers in order to directly compare H 2 15 O-PET and BOLD MRI responses. List mode PET acquisition started with the injection of 750 MBq H 2 15 O simultaneously to MRI EPI sequences. Group-level statistical parametric maps were generated for GVS vs. rest contrasts of PET, MR-onset (event-related), and MR-block. All contrasts showed a similar bilateral vestibular activation pattern with remarkable proximity of activation foci. Both BOLD contrasts gave more bilateral wide-spread activation clusters than PET; no area showed contradictory signal responses. PET still confirmed the right-hemispheric lateralization of the vestibular system, whereas BOLD-onset revealed only a tendency. The reciprocal inhibitory visual-vestibular interaction concept was confirmed by PET signal decreases in primary and secondary visual cortices, and BOLD-block decreases in secondary visual areas. In conclusion, MRI activation maps contained a mixture of CBF measured using H 2 15 O-PET and additional non-CBF effects, and the activation-deactivation pattern of the BOLD-block appears to be more similar to the H 2 15 O-PET than the BOLD-onset.