Dominic J. Zerbolio

Differences between three inbred mouse strains on a wheel-turn avoidance task

C57/BL6, BALB/c and C3H mice were examined for differences in the acquisition and maintenance over sessions of wheel-turn avoidance response. The C57/BL6 s performed best and the BALB/cs worst on the first day. But the BALB/cs reached and maintained the best avoidance level and the C3Hs showed the worst maintenance. Initial day avoidance rates are viewed as related to the compatibility between the initially emitted responses of the different strains to the situation and the specific task-required response. Differential strain response to the US level are suggested as accounting for maintenance level differences.

Within-strain facilitation and disruption of avoidance learning by picrotoxin

Eighty 60 day old Swiss Webster mice, run 10 trials a day for four consecutive days in a wheel turn avoidance situation were divided into four groups of 20 Ss each. All Ss were injected with either Saline, 1.0, 2.0 or 3.0 mg/Kg of Picrotoxin at the end of each day’s session. Results indicate that Picrotoxin can facilitate or disrupt the acquisition of the CAR. A significant curvilinear trend for avoidance performance vs drug dose level was found indicating that low and moderate dosages produce increasing facilitation whereas high dosages produce debilitation of performance. The results are consistant with the perseveration-consolidation model of memory formation.

Goldfish avoidance acquisition: Is the process classical, instrumental, or a phototaxis?

Various active-avoidance procedures and controls were run using goldfish in a shuttlebox where the CS, when used, was a sudden onset of illumination. In terms of increasing “avoid- ance” performance over days of training, CS-only, response-contingent US-only, and time- lapse groups showed significant “learning,” whereas explicitly unpaired CS and US pseudo- conditioning controls and US only (where US omission is not response contingent) did not show performance increases. The use of the pseudoconditioning procedure as a learning control for this animal seems questionable. Additionally, both classically and instrumentally trained groups showed high and comparable acquisition rates, confirming earlier findings. A negative phototaxis explanation is suggested that may account for these results.

Instrumentally based conditioned avoidance response acquisition in goldfish in a simultaneous presentation task

Goldfish, run in a Y-maze, with the simultaneous presentation of a cue associated with shock and a second cue associated with safety (no US), acquired a decided preference for the safe cue. These data are interpreted as representing a clear demonstration of stimulus-specific conditioned avoidance. Because earlier research has been challenged by unusual control performances, this instrumental learning conclusion is hesitantly drawn.

Does elimination of a negative phototaxis eliminate CAR acquisition in goldfish

Eleven groups run under classical, instrumental, pseudoconditioning, CS-only, US-only, and time-lapse procedures, with the ITI illuminated and a color change CS, showed that true classically trained animals do not increase CAR performance with training, whereas instru- mentally trained goldfish do. This is consistent with a phototaxic interpretation suggested in earlier work. Additionally, the finding that CS-only and time-lapse controls show high “acquisi- tion” rates, whereas pseudoconditioning controls do not, not only questions the use of the pseudoconditioning procedure as the sole learning control in this situation, but also questions a learning interpretation itself. Conclusions of what and how, or even if, goldfish learn in this apparatus seem premature.

Discriminated response patterning in goldfish with successive presentation and explicitly unpaired pseudoconditioning procedures

Goldfish show discriminated responding by shuttling in increasingly more US paired time frames than unpaired time frames both for the successive-presentation and explicitly unpaired pseudoconditioning procedures, where measurement, in addition to the CS, is made in a comparable period of the intertriai interval just prior to the US. These data strongly question stimulus-specific interpretations of response patterns arising from the use of the successive-presentation procedure, suggest that goldfish learn a conditioned inhibition to an unpaired stimulus, and may imply that the explicitly unpaired pseudoconditioning procedure is an appropriate control, in goldfish, for the successive-presentation procedure.

Spatially located visual CS effects on conditioned shuttlebox avoidance in goldfish (Carassius auratus): Further analysis

The present study investigates shuttlebox avoidance acquisition in goldfish as a function of type of stimulus change (onset of offset of light) and CS location (CS occurring on the same, opposite, or both sides relative to the fish). For the onset conditions, the CS-same produced superior acquisition to the CS-both location, which in turn was superior to the CS-opposite condition. For the offset conditions, the three CS locations yielded comparable avoidance rates. These data indicate that, in addition to activation by the stimulus change, when the CS is the onset of a localized light, aversive properties are conditioned to the CS which facilitate acquisition for the CS-same location and depress acquisition for the CS-opposite location. The offset data indicate that these directional properties are not conditioned to a localized area of darkness.

Passive avoidance in goldfish: Lack of evidence for stimulus specificity

Goldfish, acquiring a passive avoidance response, showed substantially fewer responses in trial intervals than did their yoked controls. A passive procedure, where US reinforcement occurred immediately upon response, produced superior avoidance acquisition to a punishment procedure, where, if response occurred at any time during the trial interval, US reinforcement was administered at the end of the interval. This finding is consistent with the traditional delay of reinforcement gradient. Although goldfish acquired the passive avoidance response, it appeared to be situationally generalized and not stimulus specific, as indicated by a lack of differences between animals trained with a CS and those trained without a CS during trial periods. Also, response suppression between the trial periods was shown by the general ITI response rate suppression. These findings, as well as others showing marked differences between the behavior of goldfish and that of other standard laboratory animals, strongly recommend considerable hesitancy in conclusions of what and how this organism learns.

Spatially located visual CS effects in conditioned shuttlebox avoidance in goldfish: A phototactic explanation

Earlier work found that goldfish (Carassius auratus) acquire a conditioned avoidance shuttle response (CASR) differentially as a function of CS location (same, opposite, or both tank ends) when the CS is a sudden onset of illumination, and hypothesized that subjects acquire an aversion to the light. The present study finds no evidence for a conditioned aversion, but shows initial negative phototactic effects in the onset illumination situation which occurs without acquisition. Additionally, when the localized CS is a color change rather than an illumination change, the differential effects between same and both do not occur, and the very low CASR acquisition of the opposite group is strikingly similar to a no-CS group, indicating a very low-magnitude CS for this condition. Using the negative phototaxis explanation, the failure of subjects to acquire a CASR differentially to a light offset, which does not yield the phototactic response, is understandable.

Spatially located visual CS effects in conditioned avoidance shuttle response acquisition in goldfish: Conditioned aversion or phototaxis?

Goldfish (Carassius auratus) were trained in a conditioned avoidance shuttle response (CASR) situation, where the CS was a color change which occurred on the same, opposite, or both ends of the shuttle tank. One hundred acquisition trials were administered either in a single day or in 20 trials a day for 5 consecutive days. Earlier work, using a change of illumination level CS, found different CASR acquisition rates with 1 day of training vs. training over several days. The present study finds basically the same order of acquisition rates within a single day as over days, with the exception of one group. Differences between CS location acquisition rates in earlier work (with illumination level change) and those of the present study (color change without illumination level change) are explained on the basis of negative phototaxis or confusion reactions occurring under the illumination level change situation.