Investigation of NAA and NAAG dynamics underlying visual stimulation using MEGA-PRESS in a functional MRS experiment

Autor(es)

Landim, Ricardo C. G. ^{[1, 2]} ; Edden, Richard A. E. ^{[3, 4]} ; Foerster, Bernd ^{[2, 5]} ; Li, Li Min ^{[2, 6, 7]} ; Covolan, Roberto J. M. ^{[1, 2, 6]} ; Castellano, Gabriela ^{[1, 2, 6]}

Afiliação do(s) autor(es)

^[1] Univ Estadual Campinas, UNICAMP, Inst Phys Gleb Wataghin, Neurophys Grp, Cosm Rays & Chronol Dept, Campinas, SP - Brazil

^[2] CInAPCe Program Cooperacao Interinst Apoio a Pesq, Campinas, SP - Brazil

^[3] Johns Hopkins Univ, Sch Med, Russell H Morgan Dept Radiol & Radiol Sci, Baltimore, MD 21218 - USA

^[4] Kennedy Krieger Inst, F M Kirby Ctr Funct MRI, Baltimore, MD - USA

^[5] Philips Med Syst, Sao Paulo - Brazil

^[6] BRAINN CEPID FAPESP, Brazilian Inst Neurosci & Neurotechnol, Campinas, SP - Brazil

^[7] Univ Estadual Campinas, Fac Med Sci, Dept Neurol, Campinas, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: MAGNETIC RESONANCE IMAGING; v. 34, n. 3, p. 239-245, APR 2016.
• Citações Web of Science: 14

Resumo

N-acetyl-aspartate (NAA) is responsible for the majority of the most prominent peak in H-1-MR spectra, and has been used as diagnostic marker for several pathologies. However, similar to 10% of this peak can be attributed to N-acetyl-aspartyl-glutamate (NAAG), a neuropeptide whose release may be triggered by intense neuronal activation. Separate measurement of NAA and NAAG using MRS is difficult due to large superposition of their spectra. Specifically, in functional MRS (fMRS) experiments, most work has evaluated the sum NM + NAAG, which does not appear to change during experiments. The aim of this work was to design and perform an fMRS experiment using visual stimulation and a spectral editing sequence, MEGA-PRESS, to further evaluate the individual dynamics of NM and NAAG during brain activation. The functional paradigm used consisted of three blocks, starting with a rest (baseline) block of 320 s, followed by a stimulus block (640 s) and a rest block (640 s). Twenty healthy subjects participated in this study. On average, subjects followed a pattern of NAA decrease and NAAG increase during stimulation, with a tendency to return to basal levels at the end of the paradigm, with a peak NM decrease of-(21 +/- 19)% and a peak NAAG increase of (64 62)% (Wilcoxon test p < 0.05). These results may relate to: 1) the only known NAAG synthesis pathway is from NM and glutamate; 2) a relationship between NAAG and the BOLD response. (C) 2015 Elsevier Inc. All rights reserved. (AU)

• Processo FAPESP: 05/56578-4 - Centro multimodal de neuroimagens para estudos em epilepsia
• Beneficiário: Fernando Cendes
• Modalidade de apoio: Auxílio à Pesquisa - Programa CINAPCE - Temático
• Processo FAPESP: 09/10046-2 - Espectroscopia Funcional por Ressonância Magnética (fMRS)
• Beneficiário: Gabriela Castellano
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 13/07559-3 - Instituto Brasileiro de Neurociência e Neurotecnologia - BRAINN
• Beneficiário: Fernando Cendes
• Modalidade de apoio: Auxílio à Pesquisa - Centros de Pesquisa, Inovação e Difusão - CEPIDs
• Processo FAPESP: 11/01106-1 - Utilização da fMRS para o estudo da variação de N-acetil-aspartato e N-acetil-aspartil-glutamato durante a ativação cerebral
• Beneficiário: Ricardo Cesar Giorgetti Landim
• Modalidade de apoio: Bolsas no Brasil - Mestrado