Summary: JOURNALOF NEUROPHYSIOLOGY
Vol. 66, No. 1, July 1991. Printed in U.S.A.
Somatosensory Response Properties of Contralaterally
Projecting Spinothalamic and Nonspinothalamic Neurons
in the Second Cervical Segment of the Cat
MARK V. SMITH, A. VANIA APKARIAN, AND CHARLES J. HODGE, JR.
Department of Neurosurgery, State University of New York Health ScienceCenter at Syracuse,Syracuse,New York 13210
SUMMARY AND CONCLUSIONS
I. The upper cervical spinal cord contains over one-third of the
cells of the spinothalamic tract (STT). This study investigated re-
sponse properties of contralaterally projecting STT neurons in C,
of the cat by the use of single-unit, microelectrode recordings.
Standard antidromic stimulation and collision techniques were
used to identify STT units projecting to the contralateral thala-
mus. Once an STT unit was found, its receptive field (RF) and
responses to cutaneous stimuli such as touch, pressure, deep mus-
cle squeeze, tap, noxious pinch, and heat were characterized. C2
units that were not activated from the contralateral thalamus
(non-STT units) were also characterized. The locations of tha-
lamic stimulation electrodes and spinal recording sites were recon-