Somatosensory evoked potential (SEP) peak amplitude has been shown to correlate with pain sensation when the level of noxious stimulation is varied. Operantly conditioned changes in SEP peak amplitude have been shown to produce significant changes in pain sensitivity. Thus, the SEP holds considerable promise for providing a non-invasive means of measuring and controlling pain-related physiological processes in man. Previous research in both these areas has been hampered by the multiple component nature of the SEP peaks. Components generated by non-pain-related neurons can mask those generated by pain-related neurons and obscure the relationship between the SEP peak and pain processes. The proposed work will investigate the relationship between the SEP and pain processes using procedures that will better separate and identify the different components underlying the SEP peaks. First, an indifferent reference electrode site will be determined to minimize contamination by components recorded from the reference site. Second, a quantitative scalp topographic analysis, the first of its kind in pain-related SEP studies, will determine the temporal and spatial (amplitude at each scalp location and pattern) features of the SEP that best correlate with perceived magnitude ratings and changes in the level of noxious and innocuous afferent input. Third, the P180 peak of the SEP will be operantly conditioned and its effect on pain sensitivity investigated. Control groups will evaluate whether the change in pain sensitivity is due to non-specific psychological factors, e.g., expectation, attention, etc., or is specific to conditioned changes in the SEP. The SEP scalp topography will be analyzed to determine whether spatial and temporal features of the SEP best related to pain sensitivity observed during conditioning are similar to those determined in the experiments that varied afferent input.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
First Independent Research Support & Transition (FIRST) Awards (R29)
Project #
1R29NS028797-01
Application #
3478110
Study Section
Sensory Disorders and Language Study Section (CMS)
Project Start
1990-08-01
Project End
1995-07-31
Budget Start
1990-08-01
Budget End
1991-07-31
Support Year
1
Fiscal Year
1990
Total Cost
Indirect Cost
Name
Clarkson University
Department
Type
Schools of Arts and Sciences
DUNS #
041590993
City
Potsdam
State
NY
Country
United States
Zip Code
13699
Dowman, R (1997) Interstimulus interval has no effect on a mid-latency scalp potential generated by innocuous-related activity in the primary somatosensory cortex. Brain Topogr 10:145-54
Dowman, R (1996) Effects of operantly conditioning the amplitude of the P200 peak of the SEP on pain sensitivity and the spinal nociceptive withdrawal reflex in humans. Psychophysiology 33:252-61
Dowman, R; Zimmer, D (1996) Heat pain increases the perceived magnitude of an innocuous electrical stimulus: evidence for a peripheral mechanism. Somatosens Mot Res 13:255-62
Dowman, R (1996) Effects of interstimulus interval on scalp topographies evoked by noxious sural nerve stimulation. Psychophysiology 33:398-408
Dowman, R; Bridgman, P M (1995) Effects of a selective A beta afferent block on the pain-related SEP scalp topography. Brain Topogr 8:57-65
Dowman, R (1994) SEP topographies elicited by innocuous and noxious sural nerve stimulation. II. Effects of stimulus intensity on topographic pattern and amplitude. Electroencephalogr Clin Neurophysiol 92:303-15
Dowman, R; Darcey, T M (1994) SEP topographies elicited by innocuous and noxious sural nerve stimulation. III. Dipole source localization analysis. Electroencephalogr Clin Neurophysiol 92:373-91
Dowman, R (1994) SEP topographies elicited by innocuous and noxious sural nerve stimulation. I. Identification of stable periods and individual differences. Electroencephalogr Clin Neurophysiol 92:291-302
Dowman, R (1993) A noninvasive strategy for identifying and quantifying innocuous and nociceptive peripheral afferent activity evoked by nerve stimulation. Physiol Behav 53:1163-9
Dowman, R; Goshko, L (1992) Evaluation of reference sites for scalp potentials evoked by painful and non-painful sural nerve stimulation. Electroencephalogr Clin Neurophysiol 84:477-85

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