. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. DIES () SURVIVES () (A3-A6) (A3-A6). DIES () () Figurt 2. Life history of proleg motoneurons. (Top) Drawings show a larva, pupa, and adult Maiulitca with abdominal segments 3, 4. 5, and 6 indicated. (Bottom (Camera lucida drawings of cobalt-stained PPRs and APRs are shown on day L3 (final instar larva before the onset of metamorphosis), day PO (first day of pupal life), day P2 (third day of pupal life), pharate adult (the final day of pupal life), and in the adult moth several days after emergence. The se
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. DIES () SURVIVES () (A3-A6) (A3-A6). DIES () () Figurt 2. Life history of proleg motoneurons. (Top) Drawings show a larva, pupa, and adult Maiulitca with abdominal segments 3, 4. 5, and 6 indicated. (Bottom (Camera lucida drawings of cobalt-stained PPRs and APRs are shown on day L3 (final instar larva before the onset of metamorphosis), day PO (first day of pupal life), day P2 (third day of pupal life), pharate adult (the final day of pupal life), and in the adult moth several days after emergence. The segmental locations of the neurons are indicated in parentheses. PPRs in all segments regress by day PO and die by day P2. APRs in all segments regress by day PO. but only those in segments A5 and A6 die by day P2. The APRs that survive in segments A3 and A4 show dendritic regrowth during the pupal stage and die after adult emergence. Data from Weeks and Ernst-Utzschneider (1989). decreased to the same extent as in normal pupae, sug- gesting that metamorphic changes in PH sensory neu- rons are not necessary and metamorphic changes in cen- tral neurons (motoneurons and interneurons) are suffi- cient for the weakening of excitatory pathways in the PWR circuit (Jacobs and Weeks, 1990; Streichert and Weeks, 1995). One limitation of these experiments was that the cEPSP is a mixture of mono- and polysynaptic inputs to the motoneurons and hence does not reveal how individ- ual synapses change during metamorphosis. To test more explicitly the hypothesis that dendritic regression disconnects synaptic inputs to the motoneurons, we measured the amplitude of monosynaptic EPSPs pro- duced in APR by individual PH sensory neurons in lar- vae and heterochronic mosaic pupae. At both stages. EPSP amplitude was correlated with the position of the PH on the proleg (Fig. 3A), but the key finding was the EPSP amplitude decreased significantly in all regions of the PH array during the larval-pupal tran
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
