. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. PINK AND RED MUSCLE ACTIVITY IN SCUP 147 the thin pink layer or the overlying red muscle was verified through dissection after each experiment. Also, the nature of the signal indicated that cross-talk between red and pink muscle recordings was not occurring. The pink and red muscle EMG waveforms at one position were not the same. The EMGs from swimming fish were analyzed using custom macros in DATAPAC software. The semi-auto- mated analysis of the EMG computer files permitted char- acterization of bursts of electromyographic
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. PINK AND RED MUSCLE ACTIVITY IN SCUP 147 the thin pink layer or the overlying red muscle was verified through dissection after each experiment. Also, the nature of the signal indicated that cross-talk between red and pink muscle recordings was not occurring. The pink and red muscle EMG waveforms at one position were not the same. The EMGs from swimming fish were analyzed using custom macros in DATAPAC software. The semi-auto- mated analysis of the EMG computer files permitted char- acterization of bursts of electromyographic activity. For each muscle fiber type at each longitudinal position, several variables relating to muscle activity were measured at each swimming speed. First, swimming speed of initial recruit- ment, or the minimum speed at which bursts of activity could be detected, was determined for each fiber type at each position. Bursts were identified by an algorithm that examined the first derivative at each point in a rectified EMG trace. For each rectified trace, a threshold was set to distinguish the slowly varying background noise from the spikes of electromyographic activity. Spikes were identified as points in the trace that exceeded this threshold, and each burst was then identified as a string of consecutive spikes. Burst duration, or the length of each electromyographic burst, was expressed as duty cycle, the duration of muscle activity as a proportion of the period of tailbeat oscillation. The relative timing of the onset of activity in red and pink muscle in each tailbeat cycle was also analyzed. The phase difference between the times of activity onset in red and pink muscle was determined for each fish at each longitu- dinal position for each swimming speed. Phase difference was expressed as a proportion of the oscillation period. Positive values indicate that the activity of red muscle occurred before that of pink muscle; negative values indi- cate that pink muscle activit
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
