Document Detail


Sensitivity of BOLD response to increasing visual contrast: spin echo versus gradient echo EPI.
MedLine Citation:
PMID:  23707589     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
Previous evidence showed that spin-echo (SE) BOLD signals offer an increased linearity and promptness with respect to gradient-echo (GE) acquisition, possibly providing a more accurate estimate of the amplitude of neuronal activity. However there is no evidence that the two sequences differ in representing different activation levels due to changes in stimulus intensity. In this study at 3T we compared GE and SE BOLD responses to visual stimuli at increasing contrast levels (5%, 20%, 60%, 100%). Both sequences showed a monotonic increase of the BOLD response with stimulus contrast. While the larger sensitivity of GE yielded overall larger signal changes, step-wise increase in activation for GE was significant only when comparing 20% with 5% contrast, whereas for SE a significant increase was observed also when comparing 60% with 20% contrast. Moreover, BOLD responses normalized to the lowest contrast showed that relative increases of SE fMRI signal with increasing stimulus strength are larger with respect to the corresponding values of GE signal. This difference was observed also when excluding voxels attributed to large vessels, suggesting a non negligible role of the extravascular contribution to the modulation of SE fMRI signal with stimulus intensity. These results are shown to be in agreement with theoretical predictions that we derived from a recently proposed model of GE and SE functional signals. The present findings suggest that, despite the limited increase in functional localization accuracy at low field, SE fMRI might offer a potential advantage in distinguishing different levels of stimulus-evoked brain activity.
Authors:
Piero Chiacchiaretta; Gian Luca Romani; Antonio Ferretti
Related Documents :
17209749 - Stereo and motion parallax cues in human 3d vision: can they vanish without a trace?
9404489 - Lightness and junctions.
11596069 - Ernst mach and the episode of the monocular depth sensations.
4034159 - Binocular disparity in visual evoked responses. clinical evidence in normal and stereob...
8838169 - How is motion disparity integrated with binocular disparity in depth perception?
3418429 - Dependence of panum's fusional area on local retinal stimulation.
21918299 - Role of dopant concentration, crystal phase and particle size on microbial inactivation...
15135919 - Responsiveness of c-fiber nociceptors to punctate force-controlled stimuli in isolated ...
11580769 - Study on photo-pattern sensitivity in patients with electronic screen game-induced seiz...
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2013-5-23
Journal Detail:
Title:  NeuroImage     Volume:  -     ISSN:  1095-9572     ISO Abbreviation:  Neuroimage     Publication Date:  2013 May 
Date Detail:
Created Date:  2013-5-27     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9215515     Medline TA:  Neuroimage     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Copyright Information:
Copyright © 2013. Published by Elsevier Inc.
Affiliation:
Department of Neuroscience and Imaging, University "G. d'Annunzio" of Chieti, Italy; Institute for Advanced Biomedical Technologies (ITAB), University "G. d'Annunzio" Foundation, Chieti, Italy. Electronic address: p.chiacchiaretta@unich.it.
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Descriptor/Qualifier:

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


Previous Document:  Transcriptomics of cortical gray matter thickness decline during normal aging.
Next Document:  Risk-taking and social exclusion in adolescence: neural mechanisms underlying peer influences on dec...