Detecting Activity-evoked PH Changes in Human Brain

Download or read book Detecting Activity-evoked PH Changes in Human Brain written by Hye Young Heo and published by . This book was released on 2013 with total page 147 pages. Available in PDF, EPUB and Kindle. Book excerpt: Localized pH changes have been suggested to occur in the brain during normal function. However, a lack of methods for non-invasively measuring pH with high spatial and temporal resolution limits current knowledge of brain pH dynamics. Here I report that a magnetic resonance imaging (MRI) strategy named T1 relaxation in the rotating frame (T1[rho]) is sufficiently sensitive to detect widespread pH changes in the mouse and human brain evoked by systemically manipulating carbon dioxide (CO2) or bicarbonate (HCO3). Moreover, T1[rho] detected changes suggesting a localized acidosis in the human visual cortex induced by a flashing checkerboard. Lactate measurements and pH-sensitive 31P spectroscopy at the same site also suggest a localized acidosis. Consistent with the established role for pH in blood flow recruitment, T1[rho] correlated with blood oxygenation level dependent contrast (BOLD), although T1[rho] was directly sensitive to blood oxygen content. These observations provide the strongest evidence thus far for localized pH fluctuations in the human brain during normal function ...