Brain activation upon selective stimulation of cutaneous C- and Adelta-fibers.
Thermal and nociceptive cutaneous stimuli activate the brain via two types of nerve fibers, slightly myelinated Adelta-fibers with moderate conduction velocity and unmyelinated C-fibers with slow conduction velocity. Differences in central processing upon selective stimulation of these two fiber types in healthy human subjects still remain poorly understood. By means of event-related functional magnetic resonance imaging the present study investigated brain activation in response to stimulation of Adelta- and C-fibers in healthy subjects. We used the stimulation of tiny skin areas to perform a selective stimulation upon cutaneous C-fibers. Besides similar activation in several brain areas in response to both kinds of stimulation, we observed pronounced brain activation to selective C-fiber stimulation as compared to Adelta-fiber stimulation in the right frontal operculum and anterior insula. Based on a putative function of these structures we suggest that the C-fiber system might be engaged in homeostatic and interoceptive functions in a manner other than the Adelta-fiber system, producing a signal of greater emotional salience.
Weiss
Thomas
T
Department of Biological and Clinical Psychology, Friedrich-Schiller-University of Jena, Am Steiger 3 Haus 1, D-07743 Jena, Germany. weiss@biopsy.uni-jena.de
Straube
Thomas
T
Boettcher
Joachim
J
Hecht
Holger
H
Spohn
Dorothee
D
Miltner
Wolfgang H R
WH
D000328:Adult; D001921:Brain / Q000502:physiology*; D004569:Electroencephalography; D004585:Electrooculography; D005260:Female; D006358:Hot Temperature; D006801:Humans; D007834:Lasers; D008279:Magnetic Resonance Imaging; D008297:Male; D009413:Nerve Fibers, Myelinated / Q000502:physiology*; D036421:Nerve Fibers, Unmyelinated / Q000502:physiology*; D010100:Oxygen / Q000097:blood; D010812:Physical Stimulation; D011930:Reaction Time / Q000502:physiology; D012867:Skin / Q000294:innervation*
D010100:Oxygen