Statistical properties of near threshold responses to brief sounds in the MES auditory cortex of the anesthetized dog.

TUNTURI, ARCHIE R. Statistical properties of near threshold responses to brief sounds in MES auditory cortex of the anesthetized dog. Am. J. Physiol. Ig6(6): I 168-1174. Igsg.-Evokedresponsesto near threshold Jo pulses recorded with a so-channel cathode ray oscilloscope from the MES auditory cortex were analyzed statistically. Observations were taken at 3-msec. epochs for approximately 180 msec. Density functions of the evoked potential at these epochs were essentially normal. The average potential from a single electrode consisted of an initial positive followed by a negative component. The correlation coefficient between the positive and negative components was zero suggesting independence. Standard deviation increased during the positive component of a response decreasing to the zero crossing or was followed by a secondary component. Spatially, in the anteriorposterior direction, the average potentials decremented to approximately zero in 2-4 mm. The decrement was less prominent dorso-ventrally. Spatially, the standard deviation showed the same pattern as the mean.