Neuroscience 2001 Abstract
| Presentation Number: | 823.1 |
|---|---|
| Abstract Title: | A COMPARISON OF CENTRAL RESPONSES TO VARIOUS AUDITORY STIMULI: A FUNCTIONAL MRI STUDY. |
| Authors: |
Fromm, S. J.*1
; Sevostianov, A.1
; Husain, F. T.1
; Rauschecker, J. P.2
; Braun, A. R.1
1NIDCD, Bethesda, MD 2Georgetown Institute for Computational and Cognitive Sciences, Georgetown Medical Center, Washington, DC |
| Primary Theme and Topics |
Sensory Systems - Auditory -- Localization |
| Session: |
823. Auditory: central physiology--functional circuitry III Poster |
| Presentation Time: | Wednesday, November 14, 2001 1:00 PM-2:00 PM |
| Location: | Exhibit Hall Q-10 |
| Keywords: | neuroimaging, temporal lobe, perception, human |
It has been hypothesized that the auditory system is hierarchically organized, with the primary auditory cortex (AI) encoding the stimulus in the most direct fashion, and upper levels in the hierarchy extracting more complex features of the stimulus. Blood-oxygenation level-dependent functional magnetic resonance imaging was used to investigate the functional organization of the cortical response to various complex, non-speech stimuli, including pure tones, band-passed noise, and upward and downward frequency modulated (FM) sweeps. 15 right-handed normal volunteers performed a one-back task while attending to binaurally presented 30s blocks of the four stimuli classes, each block consisting of stimuli of differing frequencies from the same class. Statistical maps measuring the association between hemodynamic response and stimulus class were made for each subject and combined in stereotaxic space. Bandpass noise showed greater activation than FM sweeps in right auditory cortex and inferior frontal gyrus. The pairwise contrast between up and down FM sweeps indicated that there is a more robust hemodynamic response to upward than downward sweeps. This result, while preliminary, is consistent with electrophysiological results in mammals showing an asymmetry in the number of neurons in auditory cortex which exhibit a preference for upwards versus downwards sweeps and psychophysical evidence that the human threshold for upward FM sweeps is lower than that for downward sweeps.
Supported by NIDCD/NIH
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2001 Neuroscience Meeting Planner. San Diego, CA: Society for Neuroscience, 2001. Online.
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