Neuroscience 2001 Abstract
| Presentation Number: | 48.13 |
|---|---|
| Abstract Title: | ACTIVATION PATTERNS OF NON-CONSCIOUS AND CONSCIOUS SOMATOSENSORY CORTICAL PROCESSING BY FUNCTIONAL MRI. |
| Authors: |
Blankenburg, F.*1
; Taskin, B.1
; Thees, S.1
; Meyer, R.1
; Moosmann, M.1
; Wobst, P.1
; Villringer, A.1
1Neurology, Charite Humboldt-University Berlin, Berlin, Germany |
| Primary Theme and Topics |
Sensory Systems - Tactile/Somatosensory -- Pathways and processing |
| Session: |
48. Tactile/somatosensory: imaging Poster |
| Presentation Time: | Sunday, November 11, 2001 8:00 AM-9:00 AM |
| Location: | Exhibit Hall F-60 |
| Keywords: | somatosensory cortex, subthreshold and suprathreshold tactile stimulation, conscious and non-conscious perception, electrical finger stimulation |
It is still unclear to what extent cortical areas are involved in non-conscious processing of tactile stimuli. However, from subdural recordings of somatosensory evoked potentials in awake humans there is evidence for excitation of areas in the postcentral gyrus in response to peripheral subliminal electrical stimulation without any associated conscious sensation (Libet et al. 1967). For further investigation an fMRI study (6 subjects, mean age±S.D.=27.7±2.3 yrs) was performed with an 1.5 T scanner using echoplanar sequences (TR=2 s, FOV=256 mm, voxel size=4×4×5 mm, 16 slices). Blocks (10 scans) of subthreshold and suprathreshold electrical stimuli (pulse frequency=7 Hz, pulse duration=0.2 ms), at least 15% below (2.2±0.42 mA) and 15% above (3.1±0.62 mA) sensory threshold for conscious perception (2.7±0.52 mA), respectively, were scan triggered and delivered in a randomized order to the left index finger via ring electrodes. Parametrical maps were calculated using BrainVoyager. In the group analysis, subthreshold stimulation is followed by a highly significant change of BOLD signal in contralateral as well as ipsilateral SI and the posterior-parietal cortex. Suprathreshold stimulation leads in addition to robust activations in contralateral SII and bilaterally in the insular region. Furthermore, areas bilaterally in the medial frontal gyrus are activated. These results indicate that cortical processing of subthreshold tactile stimuli can be detected by fMRI and suggest that various cortical areas participate in conscious somatosensory perception.
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2001 Neuroscience Meeting Planner. San Diego, CA: Society for Neuroscience, 2001. Online.
Copyright © 2001-2025 Society for Neuroscience; all rights reserved. Permission to republish any abstract or part of any abstract in any form must be obtained in writing by SfN office prior to publication.
