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Our early assessments of seismic sensitivity were based on phase-locked analysis of spike
responses to sinusoidal, dorsoventral vibration. The data were digitized and analyzed with
software developed by Hironori and Ken Krieg. For each of the four graphs shown here, a
70-Hz vibratory stimulus was applied for ten seconds while spikes were collected. That
corresponds to 700 stimulus cycles altogether. Beginning precisely where the sinusoidal
stimulus passed through the zero value (acceleration = 0) with a positive slope, each
stimulus cycle was divided into 100 equal, discrete intervals (each representing 0.02pi
radians or 3.6 degrees of phase, which would be 1/7 ms for the 70-Hz sinusoid). The ordinate
represents the number of spikes collected in each of those 0.02pi-radian phase increments
over the entire ten-second stimulus presentation. For each ten-second presentation, the
peak amplitude of the sinusoidal stimulus was held constant (0.01 cm/s^2 for the upper left,
0.02 cm/s^2 for the upper right, 0.07 cm/s^2 for the lower left, 0.2 cm/s^2 for the lower right).
most recently updated 07/18/07