Event-related fMRI of the auditory cortex.
An event-related protocol was designed to permit auditory fMRI studies minimally affected by the echo-planar noise artifact; a long time interval (TR = 10 s) between each cerebral volume acquisition was combined with stroboscopic data acquisition, and event-related curves were reconstructed with a 1-s resolution. The cerebral hemodynamic-response time course to a target auditory stimulus was measured in five individual subjects using this method. Clear bell-shaped event-related responses were observed bilaterally in all individuals in primary auditory cortex (A1) as well as in laterally extending secondary cortical fields. Group-average event-related curves attained their maxima (0.5-0.7%) 3 s after stimulus onset in A1 (4 s for more anterior and lateral regions of auditory cortex), and signal had returned to near-baseline level 6 s after stimulus onset. The stroboscopic event-related method appeared effective in minimizing effects of the interaction between scanning noise and experimental auditory stimulation; it adds useful temporal information to the spatial resolution afforded by fMRI in studies of human auditory function, while allowing presentation of auditory stimuli on a silent background.
Belin
P
P
Montreal Neurological Institute, McGill University, Montréal, Quebec, H3A 2B4, Canada.
Zatorre
R J
RJ
Hoge
R
R
Evans
A C
AC
Pike
B
B
D000161:Acoustic Stimulation; D000328:Adult; D001303:Auditory Cortex / Q000033:anatomy & histology / Q000098:blood supply / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods*; D002560:Cerebrovascular Circulation; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005260:Female; D006439:Hemodynamics; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D012039:Regional Blood Flow