Measurement of brain activity by near-infrared light.
We review our most recent results on near-IR studies of human brain activity, which have been evolving in two directions: detection of neuronal signals and measurements of functional hemodynamics. We discuss results obtained so far, describing in detail the techniques we developed for detecting neuronal activity, and presenting results of a study that, as we believe, confirms the feasibility of neuronal signal detection. We review our results on near-IR measurements of cerebral hemodynamics, which are performed simultaneously with functional magnetic resonance imaging (MRI) These results confirm the cerebral origin of hemodynamic signals measured by optical techniques on the surface of the head. We also show how near-IR methods can be used to study the underlying physiology of functional MRI signals.
Gratton
Enrico
E
University of Illinois at Urbana Champaign, Laboratory for Fluorescence Dynamics, 110 W. Green Street, Urbana, Illinois 61801, USA.
Toronov
Vladislav
V
Wolf
Ursula
U
Wolf
Martin
M
Webb
Andrew
A
D001921:Brain / Q000166:cytology / Q000502:physiology*; D002560:Cerebrovascular Circulation / Q000502:physiology; D006439:Hemodynamics; D006801:Humans; D007259:Infrared Rays; D008279:Magnetic Resonance Imaging; D009474:Neurons / Q000502:physiology; D010100:Oxygen / Q000097:blood; D019265:Spectroscopy, Near-Infrared; D013997:Time Factors
D010100:Oxygen