Organization of cephalopod chromatophore systems: a neuromuscular image-generator
Packard, A. (1995). Organization of cephalopod chromatophore systems: a neuromuscular image-generator, in: Abbott, N.J. et al. Cephalopod neurobiology: neuroscience studies in squid, octopus and cuttlefish. pp. 331-367
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Abstract |
The skin of some common cephalopods contains several hundred chromatophores per mm². Modulation of chiaroscuro (brightness contrast) information through differential expansion of these during natural patterning employs combinations of distinct components (up to 40 in some species). The physiological mechanisms and spatial characteristics of the motor units involve principles used in the half-tone process and tuned to the visual perception processes of animals. They can be traced (a) to epigenesis of the skin and facultative coupling between chromatophores, controlled in part by firing frequency, and (b) to central coupling between motor units of a given class and reciprocal inhibition between spatially complementary units. Myogenic coordination within populations of chromatophores that behave in many ways like visceral muscle is reversibly suppressed by nerves (denervation studies). A revised view of the role of higher and lower brain centres in the selection, integration and modulation process is presented in the light of recent evidence. |
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