Neuroscience 2000 Abstract
| Presentation Number: | 645.17 |
|---|---|
| Abstract Title: | Probing neuronal events by functional MRI at milliseconds neural time scale. |
| Authors: |
Ogawa, S.*1
; Lee, T. M.1
; Stepnoski, R.1
; Chen, W.2
; Zhu, X. H.2
; Ugurbil, K.2
1Bell Labs/Lucant Tech., Murray Hill, NJ 2CMRR, Univ. Minnesota, Minneapolis, MN |
| Primary Theme and Topics |
H. Other Systems of the CNS - 101. Brain metabolism and blood flow |
| Secondary Theme and Topics | F. Sensory Systems<br />- 72. Somatosensory cortex and thalamocortical relationships |
| Session: |
645. Brain metabolism and blood flow: human studies Poster |
| Presentation Time: | Wednesday, November 8, 2000 8:00 AM-9:00 AM |
| Location: | Hall G-J |
| Keywords: | SOMATOSENSORY EVOKED POTENTIAL, CROS-HEMISPHERE INTERACTION, BOLD SIGNAL, REFRACTORY PERIOD |
With a paradigm of forepaw stimulation in a rat model, where identical stimulation was repeated with the inter-stimulus interval (ISI) longer than ~600msec, SEP was the same for these stimuli and BOLD signal was proportional to the number of stimuli (between 1 to at least 4). However, when ISI was shorter, the induced SEP was lower and its pattern changed for the successive stimulation events following the first. The corresponding BOLD signal was also reduced and no longer proportional to the number of stimuli. The fMRI signal and the SEP induced by a pair of stimuli showed a neural refractory period lasted longer than 600 msec. In another paradigm where the left and right forepaws were stimulated once each at different times (ISI between 0 to 100 msec), an inhibitive cross-hemisphere interaction appeared in SEP and BOLD signal at ISI of 30-40 msec. We saw similar refractory phenomena in the human brain. With two short visual stimulation pulses, there was observed a neural refractory suppression of the second activation in V1 area at ISI below 1 sec. On the other hand, when the ISI was similar or shorter than the latency time of visual evoked potential (~100 msec), the suppression of the second activation was apparently absent as judged by fMRI signal intensity. These observations show that fMRI signal, in spite of its slow response time of seconds, does have a capability in its signal intensity to probe certain evoked neural events happening in the time domain of milliseconds. The temporal information comes from the ISI of the preparative and sampling tasks, such as the above pair of stimulus pulses, of the paradigm.
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2000 Neuroscience Meeting Planner. New Orleans, LA: Society for Neuroscience, 2000. Online.
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