Neuroscience 2005 Abstract
| Presentation Number: | 15.5 |
|---|---|
| Abstract Title: | Rate effect in nonhuman primate somatosensory-evoked fields. |
| Authors: |
Zhu, Z.*1,2
; Nagarajan, S. S.1
; Zumer, J. M.1
; Krubitzer, L. A.2
; Lowenthal, M. E.2
; Disbrow, E. A.1,2
1Dept. Radiology, UC San Francisco, San Francisco, CA 2CA, Biomagnetic Imaging Lab, UCSF, 94143-0628, |
| Primary Theme and Topics |
Sensory and Motor Systems - Tactile/Somatosensory -- Thalamus and Cortex |
| Session: |
15. Tactile/Somatosensory: Thalamus and Cortex I Slide |
| Presentation Time: | Saturday, November 12, 2005 2:00 PM-2:15 PM |
| Location: | Washington Convention Center - Room 201 |
| Keywords: | MEG, MONKEY, SOMATOSENSORY CORTEX, SEF |
The amplitude of the somatosensory evoked field (SEF) decreases with increasing rate of stimulation in human primary (S1) and secondary (S2) somatosensory cortex (e.g. Zhu et al, SFN 2004). Our goal is to compare the rate effect observed in the MEG signal to underlying electrophysiology. As a first step we have developed a non-human primate model to examine somatosensory cortex while varying the tactile stimulation rate. We also compare these data with our findings from humans. SEFs were recorded from anaesthetized macaque monkeys (3-5 mg/kg/hr Ketamine and 0.18-0.36 mg/kg/hr Midazolam, IV) using whole-head magnetoencephalography (MEG; Omega 2000 Whole-Cortex MEG System; CTF Systems Inc.). Pneumatically driven pulses (25 PSI, 30ms) were applied simultaneously to the tips of D1 and D2 with three inter-stimulus intervals (ISI): 330ms, 1s and 2s, with a jitter of 50ms. Blocks of 512 trials were presented in random order. Data were collected at a sample rate of 1200 Hz. The filtering passband for data analysis was 2-300 Hz. Response latency in monkey cortex was shorter than in the analogous human brain areas: the first response peak (localized to contralateral 3b/1) was 15ms (± 2ms) post-stimulus in the monkey, compared to 47ms in human. As in humans, the latency of the second peak (localized to the upper bank of the lateral sulcus) was highly variable. Further, increasing stimulation rate resulted in decreased signal amplitude. In S1, high rate (330ms ISI) and medium rate (1s ISI) response amplitudes were decreased 38.4±4.7 % and 21.4±10.1 %, respectively compared with low rate (2s ISI) stimulation. In S2, high and medium rate response amplitudes decreased 39.5±12.7 % and 20.5±1.6 %, respectively. Our results indicate that the macaque monkey is a viable model for comparing MEG data on rate effects in S1 and S2 to underlying neural signals from electrophysiological recording data.
Supported by NIH RO1NS044590, R01DC004855
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2005 Neuroscience Meeting Planner. Washington, DC: Society for Neuroscience, 2005. Online.
Copyright © 2005-2026 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.
