. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 5mV 10s 0) ta O Q. in 0) tr - log/ Figure 5. (A-F) Effect of light of different intensities on a photosen- sitive neuron within a cluster of cell bodies at the base of the left dorsal nerve of the 9th ganglion. Light stimuli between — and log units were successively applied at intervals of several minutes. (G) The number of action potentials at each intensity of light was normalized with the number of action potentials at the maximum intensity of light
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 5mV 10s 0) ta O Q. in 0) tr - log/ Figure 5. (A-F) Effect of light of different intensities on a photosen- sitive neuron within a cluster of cell bodies at the base of the left dorsal nerve of the 9th ganglion. Light stimuli between — and log units were successively applied at intervals of several minutes. (G) The number of action potentials at each intensity of light was normalized with the number of action potentials at the maximum intensity of light and plotted against different intensities. 1966), photoreceptors adjacent to the optic ganglia (Snod- derly, 1971), photoreceptors in the median optic nerves (Sarnie et «/., 1995), and photoreceptors in the telson (Hanna et 1988). Here, we found new photosensitive neurons in the opisthosomal ventral nerve cord. These often exhibited spontaneous action potentials in the dark and an increase in the number of action potentials in light. The latency of the response to light was on the order of seconds. The frequency of action potentials was maintained during illumination and modulated by light intensity over a 2-log unit. The peak spectral response was at 425 nm or lower. Are photosensitive neurons photoreceptors? In Limitlus. ventral photoreceptors and photoreceptor cells of the lateral and median eyes respond to light with a transient peak depolarization followed by a steady-state depolarization (Hartline etal, 1952; Millecchia el ai. 1966; Nolle and Brown, 1972). On the other hand, the response of photosensitive neurons in the Limulus ventral nerve cord exhibits tonic discharges to light with little adaptation, which is similar to the response of the caudal crayfish photoreceptor (CPR) of the crayfish (Kennedy, 1958, 1963; Wilkens and Larimer, 1972). In the crayfish ventral nerve cord, primary photoreceptors are identified by at least two criteria: the production of a s
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
