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Detection of the early negative response in fMRI at 1.5 Tesla
Author(s) -
Yacoub E.,
Hu X.
Publication year - 1999
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/(sici)1522-2594(199906)41:6<1088::aid-mrm3>3.0.co;2-q
Subject(s) - nuclear magnetic resonance , magnetic resonance imaging , transient response , functional magnetic resonance imaging , haemodynamic response , nuclear medicine , physics , neuroscience , medicine , psychology , radiology , electrical engineering , engineering , heart rate , blood pressure
Recent experimental studies have revealed an initial decrease in magnetic resonance (MR) signal that is consistent with optical imaging results. This initial response, thought to arise from a transient increase in deoxyhemoglobin concentration, is probably more localized to the site of neuronal activation. However, with MR imaging, this early response has only been demonstrated at high fields. In this paper, the observation of the initial response at 1.5 T is reported. Compared with results obtained at 4 T, the present study reveals that the initial response grows more rapidly with the field strength than the late positive response, suggesting a more microvascular origin of the initial response. Magn Reson Med 41:1088–1092, 1999. © 1999 Wiley‐Liss, Inc.