Responses of Contralateral SI and SII in Cat to Same-Site Cutaneous Flutter Versus Vibration

• Published in: Journal of neurophysiology Vol. 82; no. 4; pp. 1982 - 1992
• Main Authors: Tommerdahl, M, Whitsel, B. L, Favorov, O. V, Metz, C. B, O'Quinn, B. L
• Format: Journal Article
• Language: English
• Published: United States Am Phys Soc 01-10-1999
• Subjects: Animals; Autoradiography; Brain Mapping; Carbon Radioisotopes - pharmacokinetics; Cats - physiology; Deoxyglucose - pharmacokinetics; Female; Functional Laterality; Male; Skin - innervation; Somatosensory Cortex - physiology; Time Factors; Vibration
• ISSN: 0022-3077; 1522-1598
• DOI: 10.1152/jn.1999.82.4.1982

Departments of   1 Biomedical Engineering and
  2 Cell and Molecular Physiology, University of
North Carolina, Chapel Hill, North Carolina 27599
Tommerdahl, M.,
B. L. Whitsel,
O. V. Favorov,
C. B. Metz, and
B. L. O'Quinn.
Responses of Contralateral SI and SII in Cat to Same-Site
Cutaneous Flutter Versus Vibration. J. Neurophysiol. 82: 1982-1992, 1999. The methods of
14 C-2-deoxyglucose ( 14 C-2DG) metabolic mapping
and optical intrinsic signal (OIS) imaging were used to evaluate the
response evoked in the contralateral primary somatosensory receiving
areas (SI and SII) of anesthetized cats by either 25   Hz ("flutter")
or 200 Hz ("vibration") sinusoidal vertical skin displacement
stimulation of the central pad on the distal forepaw. Unilateral 25-Hz
stimulation consistently evoked a localized region of elevated
14 C-2DG uptake in both SI and SII in the contralateral
hemisphere. In contrast, 200-Hz stimulation did not evoke elevated
14 C-2DG uptake in the contralateral SI but evoked a
prominent, localized region of increased 14 C-2DG uptake in
the contralateral SII. Experiments in which the OIS was recorded
yielded results that complemented and extended the findings obtained
with the 2DG method. First, 25-Hz central-pad stimulation evoked an
increase in absorbance in a region in the contralateral SI and SII that
corresponded closely to the region in which a similar stimulus evoked
increased 14 C-2DG uptake. Second, 200-Hz stimulation of the
central pad consistently evoked a substantial increase in absorbance in
the contralateral SII but very little or no increase in absorbance in
the contralateral SI. And third, 200-Hz central-pad stimulation usually
evoked a decrease in absorbance in the same contralateral SI region
that underwent an increase in absorbance during same-site 25-Hz
stimulation. Experiments in which the OIS responses of both SI and SII
were recorded simultaneously demonstrated that continuous (>1 s) 25-Hz central-pad stimulation evokes a prominent increase in absorbance in
both SI and SII in the contralateral hemisphere, whereas
only SII undergoes a sustained prominent increase in
absorbance in response to 200-Hz stimulation to the same central-pad
site. SI exhibits an initial, transient increase in absorbance in
response to 200-Hz stimulation and at durations of stimulation >1 s,
undergoes a decrease in absorbance. It was found that the
stimulus-evoked absorbance changes in the contralateral SI and SII are
correlated significantly during vibrotactile stimulation of the central
pad positively with 25-Hz stimulation and negatively with 200-Hz
stimulation. The findings are interpreted to indicate that 25-Hz
central-pad stimulation of the central pad evokes spatially localized
and vigorous neuronal activation within both SI and SII in the
contralateral hemisphere and that although 200-Hz stimulation evokes
vigorous and well maintained neuronal activation within the
contralateral SII, the principal effect on the contralateral SI of a
200-Hz stimulus lasting >1 s is inhibitory.