. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 420 ROBERT K. JOSEPHSON AND ROGER C. HALVERSON being confined to the closer muscle. In three animals alternation occurred in both opener and closer muscles. In these records the intervals between closer action potentials and those between opener action potentials alternated between long and short values but the intervals between an opener spike and the following closer spike were constant. Examples of these patterns are seen in Figure 8 and their implica- tions as to the central organization of elements producing the activit
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 420 ROBERT K. JOSEPHSON AND ROGER C. HALVERSON being confined to the closer muscle. In three animals alternation occurred in both opener and closer muscles. In these records the intervals between closer action potentials and those between opener action potentials alternated between long and short values but the intervals between an opener spike and the following closer spike were constant. Examples of these patterns are seen in Figure 8 and their implica- tions as to the central organization of elements producing the activity are considered in the discussion. One animal produced an unusual activity pattern in which rhythmic electrical potentials, obviously in the singing pattern, occurred in only one of two antagonistic forewing muscles being monitored (Fig. 12C). This "singing" occurred in short bursts following apparently normal warm-up activity. No sound was produced. The potentials from the closer muscle were typical of singing. The opener muscle produced no large spikes although these were present during warm-up. Low level activity in the opener channel, however, suggests that other opener muscles were firing in their normal sequence. This indicates that in the command chain there are points of lability at the level of individual muscles or motorneurones which can result in a muscle failing to participate in the usual activity pattern. Warm-up and the transition to song Singing is preceded by a warm-up period during which the forewing muscles are active. During warm-up the wings are held in the resting rather than singing position and normally antagonistic muscles fire synchronously so no wing move- ment or sound is produced (Fig. 9; Heath and Josephson, 1970). The thoracic temperature rises at about ° C/min during warm-up and at the onset of singing the thoracic temperature is about ° C. Bi. A2 B2. Please note that these images are extracted from scanned page images that m
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
