This article discusses research into the neurobiology of octopuses and their relatives over the last 50 years. It is not intended to be a comprehensive review but instead focuses on certain topics, ...some of which have proved important, some of which may be important, in understanding neurobiological problems of general interest. Yet the idea that research into cephaloped neurobiology is only relevant if it to leads directly to breakthroughs in mammalian physiology is rejected. Cephalopods, like other groups of animals, are interesting in their own right and it would be a serious mistake to regard them only as 'models' for a particular research problem. Moreover it is not likely that we shall ever understand their brains and sense organs without studying their habits and lifestyle. When we begin to do that we see that the programs in their brains must be very different from ours and this brings a realization that the comparative method is not nearly so useful when dealing with whole organisms as it is at the physico-chemical level.
Little is known about mechanoreceptors in cephalopods. The anatomical data are fragmentary. While there is good physiological evidence for the existence of mechanoreceptors in the mantle of Octopus , ...mechanoreception in the mantle and fins of decapods has not been investigated. Here the authors present physiological evidence that there are receptors along the entire length of the cuttlefish fin that respond to mechanical stimuli. Unusual structures are identified in the fin whose distribution is consistent with their being these receptors.
The C
15–C
28 fragment of the paclitaxel-like antimicrotubule agent laulimalide has been synthesized in 12 linear steps with an overall yield of 14%. The methyldihydropyran ring of the side chain was ...efficiently prepared using ring-closing olefin metathesis chemistry and the 19,20-
syn-diol was generated through the addition of a mixed vinyl zincate to a protected α-hydroxyaldehyde.
Graphic
ABSTRACT
This paper presents the first direct demonstration in a living cephalopod of neural activity associated with chromatic behaviour. It has long been known that colour change in these molluscs ...is unique in that it is brought about by chromatophores controlled neurally rather than hormonally (e.g. Hofmann, 1907). The chromato-phore muscles are innervated directly by nerves whose cell bodies lie in the brain itself (Sereni & Young, 1932; Boycott, 1953); the muscles respond tetanically when these motoneurones are stimulated above 10-15 Hz (Florey, 1966) ; electrical stimulation in the chromatophore lobes of the brain causes darkening of the skin (Boycott, 1961) ; stimulation in the optic lobes can elicit patterning (the expansion of some sets of chromatophores and the simultaneous retraction of others) (Boycott, 1961; Chichery & Chanelet, 1976). Darkening, paling and patterning can also be elicited by introducing specific neurotransmitters into the blood supplying the brain (Andrews, Messenger & Tansey, 1983). But until now no-one has successfully recorded from the nerves supplying a specific set of chromatophores in the living animal and shown changes in activity as the display is switched on and off.
Current Issues in Cephalopod Behaviour Messenger, J. B.
Journal of the Marine Biological Association of the United Kingdom,
05/1995, Letnik:
75, Številka:
2
Journal Article
Recenzirano
The fourth Cephalopod International Advisory Council (CIAC) Symposium, on The Behaviour and Natural History of Cephalopods, was held at Vico Equense, Naples, Italy, from 5 to 11 June 1994. The ...meeting comprised lectures, poster sessions, keynote review lectures and a series of workshops. These were designed to examine the present status of six key subject areas and to identify possible ways forward for research. Summaries of the main conclusions from the workshops are given here in order to draw the attention of a wider audience to some of the main issues now being debated among students of cephalopod behaviour.
A method by which small quantities (1–10 μg) of neurotransmitters can be injected into the blood supplying the brain of cephalopods has been used to produce conspicuous and instantaneous colour ...changes in the skin of the arms, head and body. Of the transmitter substances known to be present in the cephalopod brain, dopamine, noradrenalin and octopamine cause darkening when injected, acetylcholine causes paling and 5- hydroxytryptamine elicits a mottled patterning. Other evidence is presented that these substances are acting centrally to produce these effects, and the findings are related to the known organization of the lobes in the c. n. s. controlling the chromatophores.
ABSTRACT
Evidence is reviewed confirming that the eyes of Sepia move under the influence of gravity, angular acceleration and visual receptors. Visual nystagmus and optomotor responses are described ...in free-swimming Sepia; these survive bilateral destruction of the statocysts, though they are abolished by blinding. Post-rotatory nystagmus is shown by intact animals in a plain background; in bilaterally blinded animals there are post-rotatory movements of the head. These responses disappear if the statocysts are removed. The post-rotatory nystagmus of intact animals is almost completely suppressed by visual cues. Other effects of blinding and statocyst removal are described.
39 6-15 yr olds who were involved in individual counseling at a comprehensive community mental health center were interviewed using a questionnaire designed to assess their conception of ...confidentiality in the counseling experience. A significant main effect for age was found. Four variables were examined as potential predictors of S's confidentiality score. Two of the variables, which involved Ss' perception of the maintenance or violation of their confidentiality in either a past or current counseling experience, were significantly related to their overall confidentiality score. Results suggest that children gradually evolve a conception of confidentiality consistent with professional guidelines. The importance of an atmosphere of trust in the counseling relationship and the child's perception of the actual maintenance of trust in his/her own counseling experience are emphasized. (43 ref)
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