. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 216 W. F. GILLY ET AL. giant motor systems. Figure 6A illustrates such recordings from a stage 29+ embryo. Giant fiber excitation is in- dicated by an initial small, negative-going spike (2) fol- lowed by a larger positive event (3). As discussed above, the first component (2) represents arrival of the impulse in the second-order giant fiber entering the stellate gan- glion via the pallial nerve, whereas the second component (3) reflects the summed action potentials from proximal parts of the third-order giants lying within
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 216 W. F. GILLY ET AL. giant motor systems. Figure 6A illustrates such recordings from a stage 29+ embryo. Giant fiber excitation is in- dicated by an initial small, negative-going spike (2) fol- lowed by a larger positive event (3). As discussed above, the first component (2) represents arrival of the impulse in the second-order giant fiber entering the stellate gan- glion via the pallial nerve, whereas the second component (3) reflects the summed action potentials from proximal parts of the third-order giants lying within the ganglion. Thus, moving the recording electrode anteriorly along the pallial nerve amplifies the second-order event and elim- inates the third (Fig. 6B), whereas moving the electrode posteriorly along the larger stellar nerves isolates activity in the third-order giant fiber (Fig. 6C). Moving the elec- trode peripherally along one of the smaller (anterior) stellar nerves out into the muscle field shows the third-order spike followed by a large muscle potential (m. Fig. 6D). Following stimulation over the brachial ganglion, ac- tivity can be recorded at all three stages in the giant fiber pathway by placing one recording electrode over the mag- nocellular lobe and a second on the stellate ganglion. The first electrode records the first-order giant spike (1) while the other records the second- and third-order events in sequence (Figs. 7A, B). Firing of the first-order cell is invariably followed by activation of the other two elements, and the delay from the peak of the first-order spike to the start of the third- order event is only ms. The delay that precedes firing of the first-order spike during an indirect response is much longer ( 26 ms in Fig. 7A or 13 ms in Figure 6. Electrical activity in the second- and third-order giant axons in a stage 29+ Loligo embryo. Direct responses of the giant fiber pathway were generated by stimulation over the magnocellu
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
