The Central Nervous Control of Colour Change in the Minnow (Phoxinus Phoxinus L.)

1971 ◽  
Vol 54 (1) ◽  
pp. 93-102
Author(s):  
MICHAEL J. GENTLE
Keyword(s):  
Optic Tectum ◽  
Colour Change ◽  
The Other ◽  
Dorsal Part ◽  
Nervous Control ◽  
Phoxinus Phoxinus ◽  
Normal Fish

1. A series of ablations were carried out in the optic tectum of the minnow, Phoxinus phoxinus, in order to investigate its importance in colour change. 2. The presence of the anterior or posterior tectum alone one on or both sides caused persistent pallor in normal fish. 3. The presence of the anterior tectum on one side and the posterior on the other enabled the fish to adapt chromatically to its background. 4. Small bilateral removals from the dorsal part of the optic tectum did not effect colour change. Larger removals from the dorsal tectum reduced the extent of change and still larger removals caused the fish to pale on all backgrounds.

The Central Nervous Control of Colour Change in the Minnow (Phoxinus Phoxinus L.)

1971 ◽  
Vol 54 (1) ◽  
pp. 83-91
Author(s):  
MICHAEL J. GENTLE
Keyword(s):  
Optic Nerve ◽  
Optic Tectum ◽  
Posterior Part ◽  
Colour Change ◽  
Complete Removal ◽  
The Other ◽  
Nervous Control ◽  
Phoxinus Phoxinus ◽  
External Conditions

1. The colour of the minnow Phoxinus phoxinus L. and its ability to undergo colour change were studied after partial and complete blinding. The blinding was accomplished either by section of the optic nerve or by tectal ablation. 2. Following bilateral section of the optic nerve the blinded minnows darken. After the initial darkening, half of the fish pale and the other half remain dark. 3. The colour of the fish blinded by bilateral section of the optic nerve could not be affected by external conditions. 4. Following complete removal of the optic tectum the fish at first paled, but after 24 h they darkened to very variable tints. 5. Unilateral section of the optic nerve coupled with unilateral tectal removal on the same or opposite side did not affect the ability of the fish to change colour. 6. The bilateral removal of the anterior tectum from a blinded darkened fish did not affect its colour. 7. The bilateral removal of the posterior tectum of a darkened fish caused maximal pallor. 8. By a series of lesions an area in the dorsal posterior part of the optic tectum was found to cause darkening in the blinded fish because following its removal the fish paled. 9. It is suggested that the fibres from the tectum may act by exciting or inhibiting the neurones of the paling centre in the anterior medulla.

Erratum

1971 ◽  
Vol 54 (1) ◽  
pp. 1-1
Author(s):  
GENTLE M. J.
Keyword(s):  
Colour Change ◽  
Nervous Control ◽  
Phoxinus Phoxinus

The central nervous control of colour change in the minnow (Phoxinus phoxinus L.) Discussion, line 4: Delete ‘unlike the fish used by the Dijkgraaf’

Electrical Activity in the Optic Tectum and Colour Change in the Minnow (Phoxinus Phoxinus L.)

1971 ◽  
Vol 55 (3) ◽  
pp. 641-649
Author(s):  
MICHAEL J. GENTLE
Keyword(s):  
Electrical Activity ◽  
Optic Tectum ◽  
High Frequency ◽  
Colour Change ◽  
Phoxinus Phoxinus ◽  
Black Background ◽  
High Frequency Activity

1. The electrical activity of the optic tectum was recorded from the minnow under various conditions to investigate its relationship to colour change. 2. The superficial E.E.G. was found to consist of two rhythms a 6-14 Hz (20-112 V) and a 18-24 Hz (6-18 µV). 3. When the fish were deeply anaesthetized the E.E.G. was reduced virtually to nothing. 4. Almost no activity was present in the optic tectum 30 min after bilateral blinding. There was an increase in activity after 5 h and this continued for 5 or more days but never returned to normal. 5. In darkness the activity of the superficial E.E.G. first increased and then decreased, and when the eyes were re-exposed to light the activity increased again. 6. The E.E.G. patterns were recorded and analysed from various depths and positions in the optic tectum during background reversal. In the stratum plexiformeet fibrosum externum, plexiforme internum and griseum internum no changes were observed. In the stratum fibrosum profundum and griseum periventriculare an increase in the high-frequency activity of approximately 10 Hz was observed on a black background.

Specification of retinotectal connexions during development of the toad Xenopus laevis

Development ◽  
1980 ◽  
Vol 55 (1) ◽  
pp. 77-92
Author(s):  
S. C. Sharma ◽  
J. G. Hollyfield
Keyword(s):  
Xenopus Laevis ◽  
Ganglion Cell ◽  
Retinal Ganglion Cells ◽  
Optic Tectum ◽  
Ganglion Cells ◽  
The Other ◽  
Retinal Ganglion ◽  
Visual Projection ◽  
Series Of Experiments ◽  
The Right

The specification of central connexions of retinal ganglion cells was studied in Xenopus laevis. In one series of experiments, the right eye primordium was rotated 180° at embryonic stages 24–32. In the other series, the left eye was transplanted into the right orbit, and vice versa, with either 0° or 180° rotation. After metamorphosis the visual projections from the operated eye to the contralateral optic tectum were mapped electrophysiologically and compared with the normal retinotectal map. In all cases the visual projection map was rotated through the same angle as was indicated by the position of the choroidal fissure. The left eye exchanged into the right orbit retained its original axes and projected to the contralateral tectum. These results suggest that retinal ganglion cell connexions are specified before stage 24.

scholarly journals The lantern shark's light switch: turning shallow water crypsis into midwater camouflage

2010 ◽  
Vol 6 (5) ◽  
pp. 685-687 ◽  
Author(s):  
Julien M. Claes ◽  
Jérôme Mallefet
Keyword(s):  
Shallow Water ◽  
Deep Sea ◽  
Light Emission ◽  
Colour Change ◽  
Hormonal Control ◽  
Nervous Control ◽  
Luminous Bacteria ◽  
Physiological Colour Change ◽  
Physiological Suppression

Bioluminescence is a common feature in the permanent darkness of the deep-sea. In fishes, light is emitted by organs containing either photogenic cells (intrinsic photophores), which are under direct nervous control, or symbiotic luminous bacteria (symbiotic photophores), whose light is controlled by secondary means such as mechanical occlusion or physiological suppression. The intrinsic photophores of the lantern shark Etmopterus spinax were recently shown as an exception to this rule since they appear to be under hormonal control. Here, we show that hormones operate what amounts to a unique light switch, by acting on a chromatophore iris, which regulates light emission by pigment translocation. This result strongly suggests that this shark's luminescence control originates from the mechanism for physiological colour change found in shallow water sharks that also involves hormonally controlled chromatophores: the lantern shark would have turned the initial shallow water crypsis mechanism into a midwater luminous camouflage, more efficient in the deep-sea environment.

Nervous Control of Gut Movements in Lophius

1980 ◽  
Vol 60 (1) ◽  
pp. 19-30 ◽  
Author(s):  
J. Z. Young
Keyword(s):  
Nervous System ◽  
Autonomic Nervous System ◽  
Inhibitory Action ◽  
Sympathetic Nerves ◽  
The Other ◽  
Sufficient Data ◽  
Nervous Control ◽  
Autonomic Nervous ◽  
Hand Control ◽  
Excitatory Action

There are not sufficient data available to allow any general statements about the earlier stages of evolution of the autonomic nervous system and of its various transmitter mechanisms. In the previous paper (Young, 1980) it was shown that control of the stomach of elasmobranchs is largely by the inhibitory action of the sympathetic nerves, probably mediated by 5-HT. In teleostean fishes on the other hand control seems to be mainly by the cholinergic excitatory action of the vagus, especially in the more advanced (acanthopterygian) groups (Grove & Campbell, 1979a, b; Fänge & Grove, 1979).

Evidence for the participation of a melanin-concentrating hormone in physiological colour change in the eel

1984 ◽  
Vol 102 (2) ◽  
pp. 237-243 ◽  
Author(s):  
I. D. Gilham ◽  
B. I. Baker
Keyword(s):  
Colour Change ◽  
Rapid Decline ◽  
White Background ◽  
Slight Effect ◽  
Pectoral Fin ◽  
Nervous Control ◽  
Antagonistic Effects ◽  
Melanin Concentrating Hormone ◽  
Physiological Colour Change

ABSTRACT The hormonal and nervous control of colour change in the eel has been investigated. The only bioactive forms of MSH found in eel pituitary extracts or secreted by eel pituitary cultures were forms of α-MSH; no β-MSH was detected. After transfer of eels from a black to a white background, the melanin concentration in skin melanophores was accompanied by a rapid decline in plasma α-MSH titres. Hypophysectomy resulted in melanin concentration, and pituitary extracts injected into hypophysectomized eels caused melanin dispersion. This effect was eliminated if the pituitary extracts were first incubated with a specific α-MSH antiserum or if the antiserum was injected into the hypophysectomized eel. However, injection of α-MSH antiserum into intact, black-adapted eels failed to result in melanin concentration although the same antiserum was effective in causing pallor in black-adapted toads. Partially purified preparations of teleost melanin-concentrating hormone (MCH), free from catecholamines, induced melanin concentration when injected into black-adapted eels and this effect was significantly potentiated by injections of α-MSH antiserum. The denervation of melanophores on the pectoral fin had only a slight effect on the responses of the melanophores to humoral agents. It is concluded that the control of physiological colour change in the eel is largely hormonal, and involves the antagonistic effects of α-MSH and a melanin-concentrating agent which is probably MCH. J. Endocr. (1984) 102, 237–243

scholarly journals Influence of the Varnishing "Surface" Coverage on Optical Print Characteristics

2020 ◽  
Vol 14 (4) ◽  
pp. 428-433
Author(s):  
Tomislav Hudika ◽  
Igor Majnarić ◽  
Tomislav Cigula
Keyword(s):  
Surface Coverage ◽  
Colour Change ◽  
The Other ◽  
Colour Difference ◽  
Printing Process ◽  
Laboratory Environment ◽  
Uv Led ◽  
Cost Efficient ◽  
Colour Coordinates ◽  
Colour Appearance

Varnishing is often used to protect or decorate the print, but it can also influence the print’s colour appearance. Therefore, varnishing should enhance the print role, while colour change should be kept as low as possible. The aim of this paper is to evaluate inkjet UV LED varnishing by estimating optical print characteristics. Prepared offset prints were UV LED varnished in different surface coverage values (SCV) with a matte and gloss finish. The prints were evaluated by measuring gloss and colour coordinates. Secondly, varnishing was performed in a different SCV, which enabled assessing the optimal SCV, i.e. the most cost-efficient varnishing. The printing process was conducted in a standardized and controlled laboratory environment, regulated via the ISO 12647-2:2013 norm to ensure that the black colour was reproduced in the standard tolerance. The results showed that the colour difference is negligible (stays in the ISO tolerances), regardless of the varnishing SCV. On the other hand, the optimal printing gloss is at the SCV of 100%.

The Craik—O'Brien—Cornsweet Illusion in Colour: Quantitative Characterisation and Comparison with Luminance

Perception ◽  
1997 ◽  
Vol 26 (11) ◽  
pp. 1423-1430 ◽  
Author(s):  
Thomas Wachtler ◽  
Christian Wehrhahn
Keyword(s):  
Transition Region ◽  
Scale Invariance ◽  
Colour Change ◽  
The Other ◽  
Stimulus Parameters ◽  
Presentation Time ◽  
Spatial Parameters ◽  
Quantitative Characterisation ◽  
Colour Version

The strength of the Craik–O'Brien–Cornsweet illusion was measured for different values of spatial and temporal stimulus parameters, in the traditional achromatic version, and in an isoluminant colour version. It was found that the illusion is much weaker with isoluminant colour stimuli than with achromatic luminance stimuli. The illusion depends on the spatial parameters of the stimulus in a way that yields an approximate scale invariance: The strength of the illusion is similar for different stimulus sizes, as long as the ratio of the width of the transition region around the edge, where luminance or colour change, to the total stimulus width is preserved. In both the achromatic and the chromatic case, the strength of the illusion decreases with increasing presentation time. The similarity of the differences between brightness and colour effects on one hand and the differences in sensitivity for colour and luminance changes in humans on the other suggests that a lack of gradient detection underlies the Craik–O'Brien–Cornsweet illusion.

Dorsal-Enhanced Sutures Improve Tension Resistance of Tendon Repair

2002 ◽  
Vol 27 (2) ◽  
pp. 161-164 ◽  
Author(s):  
Y. CAO ◽  
R. G. XIE ◽  
J. B. TANG
Keyword(s):  
Ultimate Strength ◽  
Tensile Testing ◽  
Testing Machine ◽  
Tendon Repair ◽  
The Other ◽  
Dorsal Part ◽  
Gap Formation ◽  
Tensile Testing Machine ◽  
Finger Flexion ◽  
Main Components

Thirty-six fresh pig flexor tendons were repaired using either the modified Kessler method or the Tang method. Nine tendons from each group were tested in an Instron tensile testing machine with the tendons passing 90° around a pulley. The other nine tendons from each group were pulled linearly by the testing machine. The 2mm gap formation force of the tendons repaired with the modified Kessler and Tang methods and pulled at 90° were 64%±5% and 79%±9% respectively of those forces recorded during linear testing. The ultimate strengths of tendons repaired by the modified Kessler and Tang methods and pulled at 90° were 76%±6% and 81%±8% respectively of the forces measured during linear testing. The percentage gap formation and ultimate strength of the Tang method was significantly higher than that of the modified Kessler suture when the tendons were pulled around a pulley. This demonstrates that the Tang suture, with its main components in the dorsal part of the repaired tendon, has greater tension resistance capacity than conventional tendon sutures which are placed in the middle of the tendon. This study suggests that dorsally-enhanced multiple tendon sutures are better placed to sustain the tension generated during active finger flexion.

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