External inhibition in a goldfish(carassius auratus) classical conditioning situation

Intact goldfish in a light gradient were unevenly distributed and spent most of their time in the darker half of the gradient. Pinealectomized, bilaterally enucleated, or pinealectomized plus bilaterally enucleated goldfish were distributed uniformly throughout the light gradient. It was concluded that the phototactic response of goldfish depends upon the presence of the pineal organ as well as the eyes.In a conditioning situation, pinealectomized animals with intact vision showed significantly more responses to the conditioned stimulus than did the control animals with intact vision when the conditioned stimulus was light, but not when the conditioned stimulus was sound. Blind goldfish, with or without an intact pineal, could not be effectively conditioned to light although they did become conditioned to sound. Pinealectomy did not affect the conditioning of either the blind or the eyed goldfish to sound.Among goldfish with intact vision, pinealectomy increased the spontaneous swimming activity. Blinding enhanced the level of spontaneous swimming activity more than did pinealectomy. But blind plus pinealectomized goldfish displayed a level of spontaneous swimming activity which was intermediate between the level shown by pinealectomized eyed animals and blind animals with an intact pineal.The significance of these findings has been discussed in terms of the photosensory role of the goldfish pineal organ.

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Cue Validity in a Goldfish (Carassius Auratus) Respiratory Conditioning Situation

Psychological Reports ◽

10.2466/pr0.1977.40.3c.1247 ◽

1977 ◽

Vol 40 (3_suppl) ◽

pp. 1247-1254

Author(s):

Allen H. Wolach ◽

Stephen E. Breuning ◽

Nariman Solhkhan ◽

Peter Roccaforte

Keyword(s):

Classical Conditioning ◽

Compound Stimulus ◽

Training Group ◽

Conditioning Situation ◽

Cue Validity ◽

Goldfish Carassius Auratus ◽

Group 4 ◽

The Us ◽

The Individual ◽

Group 1

32 goldfish were classically conditioned in a respiratory conditioning situation with shock as the US and a temporary cessation of breathing as the UR. The CS was a light, a click, or a light-click compound stimulus. Fish in all four groups had classical conditioning trials with the light-click compound as CS. The groups were differentiated by additional classical conditioning with one of the elements of the compound as CS (Group 1), no presentations of the individual elements of the compound or the US (Group 2), random presentations of the US (Group 3), and non-rewarded presentations of one of the elements of the compound (Group 4). When tested with the element of the compound that was not presented alone to any of the groups during training, Group 1 showed the least evidence for conditioning, Groups 2 and 3 intermediare levels of conditioning, and Group 4 the greatest evidence for conditioning. The results were discussed in relation to hypotheses regarding continuity and attention as interpretations of cue-validity studies.

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SEM of Hepatocytes and Biliary Passages in Goldfish Liver

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100080213 ◽

1977 ◽

Vol 35 ◽

pp. 556-557

Author(s):

Waykin Nopanitaya ◽

Joe W. Grisham ◽

Johnny L. Carson

Keyword(s):

Carassius Auratus ◽

Cell Layer ◽

Three Dimensional ◽

Cell Types ◽

Biliary System ◽

Fish Food ◽

Commercial Fish ◽

Goldfish Carassius Auratus ◽

Commercial Fish Food

An interesting feature of the goldfish liver is the morphology of the hepatic plate, which is always formed by a two-cell layer of hepatocytes. Hepatic plates of the goldfish liver contain an infrequently seen second type of cell, in the centers of plates between two hepatocytes. A TEH study by Yamamoto (1) demonstrated ultrastructural differences between hepatocytes and centrally located cells in hepatic plates; the latter were classified as ductule cells of the biliary system. None of the previous studies clearly showed a three-dimensional organization of the two cell types described. In the present investigation we utilize SEM to elucidate the arrangement of hepatocytes and bile ductular cells in intralobular plates of goldfish liver.Livers from young goldfish (Carassius auratus), about 6-10 cm, fed commercial fish food were used for this study. Hepatic samples were fixed in 4% buffered paraformaldehyde, cut into pieces, fractured, osmicated, CPD, mounted Au-Pd coated, and viewed by SEM at 17-20 kV. Our observations were confined to the ultrastructure of biliary passages within intralobular plates, ductule cells, and hepatocytes.

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