J. Hennig et al., FUNCTIONAL SPECTROSCOPY - LIMITATIONS AND VALUE OF A NEW METHOD FOR EXAMINING BRAIN ACTIVITY USING MRT, RoFo. Fortschritte auf dem Gebiete der Rontgenstrahlen und der neuenbildgebenden Verfahren, 161(1), 1994, pp. 51-57
The possibility of examining brain activity by means of localised spec
troscopy was studied in relation to its neurological basis. Measuremen
ts on 18 normals during optical stimulation showed an improvement in s
ignal to noise ratio compared with functional imaging of almost one or
der of magnitude. Time dependent measurements during stimulation by a
500 ms light impulse showed definite delay of increased blood flow whe
n compared with oxygen utilisation. The excellent signal to noise rati
o and the inherent stability of the method permits reliable detection
of weak effects such as are caused by finger tapping or electrical sti
mulation.