Learning about water by hungry rats

In Experiments 1 and 2 hungry rats were trained in a straight alley with consistent food reward (FF), food and nonreward trials intermixed (FN), or food and water trials intermixed (FW). In Experiment 1 rats were tested with nonrewarded trials (extinction) and Groups FN and FW did not differ, both running faster then Group FF. In Experiment 2 rats were tested with consistent water reward, and Group FW ran faster then Group FN, which was superior to Group FF. In Experiment 3, one group of hungry rats was trained on a single alternating schedule of food and water in Phase 1 and was shifted to a single alternating schedule of food and nonreward in Phase 2 (Group FW); the second group (Group FN) received a single alternating schedule of food and nonreward in both phases. When Group FW was shifted to nonreward from water, performance to nonreward was temporarily disrupted. These results indicate that, contrary to previous conclusions, hungry rats can learn about water when drive is strong and food is received in the situation.     

Four-choice win-stay water escape acquisition by rats

Rats were capable of acquiring a four-choice win-stay water-escape task. While preventing access to the incorrect choice sections on information runs affected the first choices made on test runs, it did not affect rate of acquisition.     

Touched by water: The body in scuba diving

Focusing on the leisure practice of scuba diving, I examine how ’touch’ works as a sense experienced through material engagement with the aquatic world for both physical and metaphorical effect. Technologically facilitated and environmentally positioned, scuba diving brings together the distal and the proximate to produce a particular experience of space and a particular mobilisation of emotion. The paper positions itself within the conceptual context of embodiment in order to consider corporeality in terms of its visceral and material capacities that effect and direct movement, as well as the experience of the sensuous via an engagement with the diving environment. In doing so, it draws upon work within the social sciences that has acknowledged the importance of an embodied engagement with environments that are seen as therapeutic or restorative for their ability to instil a sense of well-being and calm through a re-centering of the self. Drawing out the meditative capacities of scuba diving, the paper considers the aquatic world as, for some divers, a therapeutic landscape.     

Analysis of water and NaCl solution acceptance by schedule-induced polydipsia

Animals were trained on a VI 1-min schedule for food pellets, and concurrent water intake was measured. The polydipsia induced was analyzed in terms of the frequency distribution of post-pellet licking burst sizes and the trend of polydipsia throughout the session. An ascending series of NaCl solutions was presented consecutively over daily sessions and a typical NaCl acceptance-rejection intake function was generated. Beginning in the 0.9-1.2% NaCl range, the animals drank less often during the session but took larger drinks when they did drink. Neither the frequency of drinks nor the mean licking burst size were simply related to the volumes of NaCl solution consumed. The NaCl acceptance-rejection function cannot be explained in terms of water repletion factors alone.     

Retrieval improvement is induced by water shortage through angiotensin II

Angiotensin II (ANGII) has an evolutionary preserved role in determining adaptative responses to water-shortages. In addition, it has been shown to modulate diverse phases of memory. Still, it is not clear whether ANGII improves or spoils memory. We demonstrated that endogenous angiotensins enhance consolidation of a long-term associative memory in the crab Chasmagnathus and that water shortage improves memory consolidation through brain ANGII actions. Here, we show that weakly trained crabs, when water-deprived, exhibit enhanced retrieval. Subsequently, memory retention is indistinguishable from that of strongly trained crabs. ANGII, but not angiotensin IV, is a necessary and sufficient condition for such enhancing effect. We conclude that ANGII released due to water shortage leads to enhanced memory retrieval. Thus, it seems that ANGII has an evolutionary preserved role as a multifunction coordinator that enables an adaptative response to water-shortage. The facilitation of memory consolidation and retrieval would be among those coordinated functions.     

Some antiepileptic compounds impair learning by rats in a Morris water maze

In the present experiments, we investigated the effects of several commonly employed antiepileptic drugs on the performance of adult rats in a Morris water maze task. We found that phenytoin treatment produced the most deleterious performance impairments across all days of training, and that these performance deficits are not likely due to any general sensorimotor impairments. Carbamazepine had milder, but detectable negative effects, as carbamazepine-treated animals exhibited initial acquisition deficits, but rapidly achieved escape levels comparable to controls. In marked contrast, valproate and ethosuximide had no detectable effects on learning in the water maze. These results parallel previous findings in rats treated with these compounds and tested in an instrumental learning task, and are in general agreement with the human clinical literature. To the extent that one might wish to minimize learning deficits associated with maintenance on antiepileptic drugs, phenytoin is definitely not the treatment of choice, while valproate or ethosuximide are apparently much less disruptive.     

Reinforcement by an imprinting stimulus versus water on simple schedules in ducklings

Ducklings (5 to 28 days old) were trained to peck a pole on fixed-ratio, fixed-interval, and multiple schedules using brief presentation of an imprinting stimulus as the response-contingent event. Other ducklings of the same age were trained similarly except that reinforcement consisted of access to water. With water reinforcement the typical fixed-ratio (“break-run”), fixed-interval (“scallop”), and multiple schedule response patterns were readily established and consistently maintained. With the imprinting stimulus these schedule effects were inconsistent in some subjects and virtually nonexistent in others, despite extended training. Schedule control with the imprinting stimulus was not improved by the use of a reinforcement signaling procedure which enhances responding reinforced by electrical brain stimulation on intermittent schedules. However, the overall rates of responding and the extinction functions generated after reinforcement with water versus the imprinting stimulus were comparable. These findings imply that control by temporal and discriminative stimuli may be relatively weak when a young organism's behavior is reinforced by presentation of an imprinting stimulus.     

Responsivity to pain in rats changed by the ingestion of flavored water

Sprague-Dawley male rats drank flavored water and subsequent pain responsivity was assessed using a hot plate first after isotonic saline and later after either 2.75 (Experiment 1) or 2.5 (Experiment 2) mg/kg of morphine hydrochloride was injected. A 48-h exposure to any one of several different flavors resulted in a reduction of the analgesic effects of morphine as shown by an attenuation of the increased latency to paw lick caused by the morphine. This effect was independent of the amount consumed. A 26-h exposure to a flavor decreased pain reactivity before and after morphine as shown by an overall increase in latency to paw lick. This effect was not influenced by whether the normally preferred flavor was made aversive by a previous pairing with lithium chloride-induced illness. These findings are consistent with the idea that many flavors, independently of palatability and amount consumed, increase the release and utilization of endogenous opioids.     

Search strategies used by APP transgenic mice during navigation in the Morris water maze

TgCRND8 mice represent a transgenic mouse model of Alzheimer's disease, with onset of cognitive impairment and increasing amyloid-beta plaques in their brains at 12 weeks of age. In this study, the spatial memory in 25- to 30-week-old TgCRND8 mice was analyzed in two reference and one working memory Morris water maze (MWM) tests. In reference memory tests, the mice were trained to escape to a hidden platform, which in one version of the test was marked by a visual cue. In the working memory test, the hidden platform was moved daily to different locations. The TgCRND8 mice were impaired in reference memory when trained in a hidden platform test. However, the mice developed spatial memory comparable to non-Tg littermates in a cued reference memory test. The mice showed also an impairment in spatial working memory. Analysis of search paths revealed that in contrast to non-Tg littermates, TgCRND8 mice did not use spatial strategies during their navigation. Instead, they learned to locate an escape platform using a nonspatial, chaining strategy. The study showed that (1) the impairment in the reference memory of TgCRND8 mice was reduced when a hidden platform was cued, and that (2) both working and reference memory systems of TgCRND8 mice, but not (3) the plasticity of choice between search strategies, are compromised by the transgene-induced pathology.     

The integration of habits maintained by food and water reinforcement through stimulus compounding.

In Experiment 1, a light and a tone were correlated independently with water reinforcement of bar pressing by rats. With different naive subjects in Experiment 2, one of these stimuli was correlated with food and the other with water reinforcement (counterbalanced). In both experiments the absence of tone and light signaled extinction. Tests of stimulus-reinforcer independence in Experiment 2 indicated that tone and light controlled behavior whose rate was specifically affected by deprivation state. In the stimulus-compounding tests of both experiments, response rates were higher to tone-plus-light than to tone or light presented alone (additive summation). This is the first report of additive summation produced through compounding stimuli paired with different reinforcers. The results are discussed in the context of the effects of incentive motivation on operant performance.     

Ranking water resource projects and evaluating criteria by multicriterion Q-analysis: an Austrian case study

A multicriterion decision-making (MCDM) concept is applied not only to provide possible solutions for a hydroecological problem but also to shed light on the discriminating capabilities of criteria. The aim is to identify a subset of a given set of criteria used to seek a satisfactory solution among several possible water resource projects being designed for the Austrian part of the Danube between Vienna and the Slovakian border. In this section the Danube is still a free-flowing river and possesses a high ecological value. There are three conflicting interests relative to this particular area, namely economic, ecological and sociological interests. The so-called multicriterion Q-analysis (MCQA) technique is applied to generate more effective discussions between conflicting groups than there have been in the past. The most preferred alternatives from among 12 possible projects, including several different hydroelectric power stations and National Park plans, are to be identified. The MCQA procedure is implemented to analyse the water resource projects with emphasis on criterion evaluation. In order to facilitate ranking alternatives, criteria with discriminating power have to be defined. For this purpose a new concept, MCQA-III, is developed and shown to be a useful tool to distinguish between important and less important criteria. MCQA techniques are based on Q-analysis, which describes the geometrical structure of the relationship between two finite sets, here the set of projects and the set of criteria. By using MCQA-I, MCQA-II and MCQA-III, a ranking of both alternatives and criteria is obtained. The MCQA-III procedure is applied to find an order among criteria which should give us more information on their importance for ranking alternatives, leading to a possible reduction of the number of criteria. This aspect plays a central role for an institution which must base its decision on a small but highly informative set of criteria. © 1997 John Wiley & Sons, Ltd.     

An assessment of response, direction and place learning by rats in a water T-maze

Behavioral data suggest that distinguishable orientations may be necessary for place learning even when distal cues define different start points in the room and a unique goal location. We examined whether changes in orientation are also important in place learning and navigation in a water T-maze. In Experiment 1, rats were trained to locate a hidden platform and given a no-platform probe trial after 16 and 64 trials with the maze moved to a new position. Direction and response strategies were more prevalent than a place strategy. In Experiment 2, acquisition of place, response and direction strategies was assessed in a water T-maze that was moved between two locations during training. Rats were impaired on the place task when the maze was translated (moved to the L or R) but were successful when the maze was rotated across trials. These data are consistent with findings from appetitive tasks.     

Pigeons' preference for variable-interval water reinforcement under widely varied water budgets.

Water budget of pigeons was varied to assess the dependence of risk-sensitive preferences upon economic context such as has been reported for energy-budget manipulations with small animals in behavioral ecology research. Fixed- and variable-interval terminal-link water schedules reinforced choice between equal variable-interval initial-link schedules arranged on two pecking keys. While keeping a severely restrictive budget the same across three phases of the experiment, a contrasting distinct ample budget was arranged in each. To mimic typical methods in behavioral ecology studies, in each ample budget a more than three-fold increase in amount of water per reinforcer presentation was instituted simultaneously with significantly increased overall access to water. Total choice response rates plummeted in the ample budgets, and body weights either increased significantly or remained unchanged in different phases as expected by the nature of the different manipulations. Clear preferences for the variable-interval schedule were found throughout the experiment, except for rare instances of key bias. The results agree with similar operant food-reinforcement studies and extend conditions under which risk preference apparently does not depend upon economic context.     

Lick-trading by rats: on the substitutability of dry, water, and saccharin tubes.

Thirsty rats licked two metal tubes: a water tube paired with another water tube, with saccharin, or with a dry tube. For each pair, a multipoint baseline function was measured by offering free access to one tube throughout each session, and free or restricted access to the other. The three resulting baseline functions showed the members of each pair to be mutual substitutes: When access to either tube was restricted, the rats made more licks at the other. A linear function identified the two water tubes as perfect substitutes. Convex functions identified the members of the saccharin-water and the dry-water pair as imperfect substitutes. Each pair was also tested under several reciprocal fixed-ratio schedules that required instrumental licking of either tube for contingent access to the other. The resulting schedule functions showed the members of each pair to be perfect substitutes: Water licks decreased linearly as licks at the other water tube, the saccharin, or the dry tube increased, in agreement with a conservation model of instrumental performance. Baseline and schedule functions, indistinguishable in the water-water pair, indicated a schedule facilitation of dry-tube licking in the dry-water pair and of water-tube licking in the saccharin-water pair.