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Rats emit a variety of calls in the 40–80 kHz range (50 kHz calls). While these calls are generally associated with positive affect, it is unclear whether certain calls might be used selectively in certain contexts. To examine this, we looked at ultrasonic calls in 30–40 day old male rats during the expectation of either play or food, both of which are reinforcing. Behavior and vocalizations were recorded while rats were in a test chamber awaiting the arrival of a play partner or food over seven days of testing. Control groups were included for the non-specific effects of food deprivation and social isolation. Play reward led to an increase in 50 kHz vocalizations, generally, with specific increases in trill and “trill with jump” calls not seen in other groups. Expectation of food reward did not lead to a significant increase in vocalizations of any type, perhaps due to the young age of our study group. Further, rats that were food deprived for the food expectation study showed markedly lower calls overall and had a different profile of call types compared to rats that were socially isolated. Taken together, the results suggest that trill-associated calls may be used selectively when rats are socially isolated and/or expecting a social encounter.

To find out whether a surface finishing was preferred under different lighting conditions by school children, in the light test chamber of the SenseLab, 335 children from previous studied schools were asked to assess a desk surface during different light conditions. A two-way randomized design was used to test children’s assessments for six school desks table tops (brown, yellow and grey wood, and, normal, matt and reflective white), under three different light conditions: energizing, calming, and focusing. A statistically relevant relationship was found for the three wooden surfaces, but none for the white ones. Such results may be due to the fact that better contrast between the participants’ form and the surface appeared with the wooden-like surfaces, as opposed to that with the white surfaces. Similarly, white surfaces’ characteristics seemed to be more difficult to assess (mattness, reflectiveness, opacity) as opposed to those for the wooden-like surfaces (colour yellow, brown, grey).

Our sensory system (nose) could predict the perceived odour intensity of various materials relatively well and in many cases the nose seems to be a better receptor of pollutants than some equipment. To test this ability with children, odour tests were performed as part of a study performed with 335 primary school children in the air quality test chamber of the SenseLab. Two similar experiments were conducted to assess the identification of potentially recognizable odours for children. The different sources of odour were placed in different containers and the children were asked how they feel about the smell and to identify the source of smell. There were statistically significant differences among children’s evaluations of different smells and it was difficult for them to identify certain sources of smell.

Previous studies have shown that next to ‘human smell’, ‘stuffy air’ is one of the discomforts that children report in classrooms. Besides, people’s olfactory system is able to recognize the perceived odour intensity of various materials relatively well and in many cases the nose seems to be a better perceiver of pollutants than some equipment. In the underlying study, the aim was to expose 335 primary children to different sources of smell, and ask them to evaluate and identify those sources at individual level with their noses. Additionally, the possible effect of plants on the reduction and/or production of smells was tested. Selected sources of odour were placed in different containers and the children were asked how they feel about the smell and to identify their source. The results showed statistically significant differences among children’s evaluations of different smells, a link between preference and recognition of odours, and, no statistical difference in the assessment of the smells when the potted plants were placed inside the CLIMPAQ. The results confirm the need to include sensory assessments in the evaluation of IAQ together with physical evaluations. Future studies on the effect of using active vegetation systems instead of passive systems are recommended.

Rats had learnt special abilities in a test chamber. The next step was to test whether these special abilities would have any influence on social interactions in a test chamber. The behavior of male BDE-rats was tested in three different situations. 1. Rat A was able to handle a central lever to get food (ability f) and rat B had learnt to press a lever in front of the test chamber to get water (ability w). 2. Rat A had learnt both abilities (f and w) and rat B had learnt neither. 3. Both animals had learnt the abilities f and w. Subsequently it might be possible that in some special test-situations one of the animals will learn from the other. In control series, therefore, other rats had to learn the ability f or w, or f and w without the presence of another rat. The results suggested that the behavior of the rats was influenced by the learnt ability. Another result was that there is no connection between the learnt ability of an animal and its social rank. The learning results of the rats which learnt alone in the test chamber (control group) were better than the results of the subjects which had the chance to learn in the presence of a partner.

and Summary In the laboratory setting, anti-predator behavior tends to habituate so fast that its value for the prey's survival appears questionable. We propose that excessive habituation is caused by the artificially stereotyped presentation of stimulus objects, which is commonly used for the sake of precise stimulus control. To test this hypothesis, we habituated young angel fish (Pterophyllum eimecki) to a moving shadow on one side of the test chamber, and then presented the moving shadow on the opposite side of the chamber. Since the responsiveness was restored in the vast majority of these trials, our hypothesis stays upheld. This result is discussed in the context of an earlier hypothesis, namely that from the prey's vantage point relative rareness is an important feature of predators in the natural setting (SCHLEIDT 1961). Zusammenfassung Nach einer fruher vertretenen Hypothese ist vom Standpunkt des Beutetieres die relative Seltenheit im naturlichen Lebensraum ein wichtiges Merkmal von Raubfeinden (SCHLEIDT 1961). In Laborversuchen gewohnen sich Beutetiere im allgemeinen schneller an Fresfeinde als fur das Uberleben tragbar erscheint. Wir nehmen an, das diese schnelle Gewohnung ein Kunstprodukt der gleichformigen Darbietung des Reizobjektes ist. Um das zu prufen, gewohnten wir junge Segelflosser (Pterophyllum eimecki) zunachst an einen sich bewegenden Schatten an einer Wand der Versuchskammer und boten dann den gleichen sich bewegenden Schatten an der gegenuberliegenden Wand. Durch diese Ortsveranderung wurde in der uberwiegenden Mehrzahl der Versuche das Feindmeidungsverhalten wiederhergestellt.

This study tested the effects of a motion-coupled display on task performance and self-reports of motion sickness for subjects experiencing motion at a frequency and intensity previously found to be nauseogenic. Subjects were randomly assigned to a control condition or a treatment condition. Both groups performed a simple computer game (Tetris) for a 30-minute period while moving forward and backward at 0.2 Hz in an enclosed chamber. In the treatment condition, a visual flow field whose movement was coupled to the motion of the enclosed test chamber was displayed behind and around a window in which subjects performed the computer game. For the control condition, the visual flow field elements were kept stationary. Contrary to expectations, no differences were found between the two groups on self-reported motion sickness symptoms; however, the treatment group performed significantly better than the control group on the computer game.

Adult rats typically exhibit more robust behavioral sensitization than do preweanling rats. A possible explanation for this age-dependent difference is that environmental context may have relatively less impact on the psychostimulant-induced behaviors of preweanling rats. The purpose of this study was to assess the importance of environmental context for the development of cocaine-induced sensitization in preweanling and adult rats. On postnatal day (PD) 19 or PD 79, rats in the context-dependent condition were injected with 30 mg/kg cocaine immediately before being placed in a novel test chamber for 30 min. The same rats were then injected with saline 30 min after being returned to the home cage. Rats in the context-independent condition were injected with saline before being placed in the novel chamber and cocaine in the home age. Control rats were injected with saline at both time points. One day later, adult and preweanling rats were challenged with saline or 10 mg/kg cocaine (experiment 1), or preweanling rats were challenged with 5, 20, or 30 mg/kg cocaine (experiment 2). After being injected, rats were placed in the test chamber, and behavior was measured for 60 min. Adult rats showed context-dependent locomotor sensitization and conditioned activity, with females exhibiting more locomotor activity than males. Preweanling rats did not exhibit conditioned activity, but they showed robust context-dependent and context-independent sensitization when challenged with 10–30 mg/kg cocaine. Context did not influence the expression of behavioral sensitization in preweanling rats, suggesting that deficits in associative or memory processes may be responsible for age-dependent differences in behavioral sensitization and conditioned activity.

Few experiments have addressed the problem of cognitive map formation in non-human primates. Therefore, a paradigm was developed to assess spatial memory formation in squirrel monkeys ( Saimiri sciureus ) moving freely in three dimensions. While moving on the walls and floor of a large test chamber, the animals learned to collect pieces of cereal from baited food-ports interspersed among non-baited ports. The cereal-pellets were not visible to the monkeys, so the animals needed to develop spatial memory to visit only the baited ports for food and avoid the non-baited ones. A session consisted of ten consecutive trials, and 3 successive sessions were conducted on each day for a 5-day period. For each trial, correct choices (CC; number of visited baited-ports) and incorrect choices (IC; number of visited non-baited ports) were registered, and spatial memory performance index (SMPI; ranging from 0.00 to 1.00) was calculated as follows: SMPI=(CC−IC)/CC. For each session, mean SMPI, session duration, total reaches into the non-baited ports, and total reaches into the baited ports were documented. In an 8-port task, where 4 food-ports were baited and 4 were non-baited, the mean SMPI was higher than 0 in the first session (day 1), indicating the development of short-term spatial memory. By the fifth session (day 2), this index was significantly higher than in the first session, indicating the build-up of long-term spatial memory. These changes were related to a significant decrease in the total reaches into the non-baited ports. At the same time, the duration of the sessions and the total reaches into the baited ports did not change significantly. This paradigm can be used for (1) studying cognitive map formation in primates, (2) examining the underlying cellular and molecular mechanisms in integrative neurobiological experiments, and (3) screening cognition-enhancer drugs in a monkey model.

Separation from conspecifics in chicks produces an increase in distress vocalizations and a decrease in response to a noxious stimulus (stress-induced analgesia). This study questioned the relative contributions of novelty to the test chamber and social separation in mediating these stress responses. Eight-day-old chicks were tested either in isolation or in the presence of two social companions for a 3-min observation period in which distress vocalizations were recorded as well as the frequency of footlifts in response to a 50-microl injection of 0.10% formalin into the plantar surface of the footpad. In Expt. 1, chicks received six, 3-min test chamber habituation trials (vs. no habituation) one per day before testing; in Expt. 2, chicks were tested with mirrors placed in the chambers (vs. no mirrors). In both studies, isolated chicks in control groups (i.e., no habituation or no mirror) exhibited increased distress vocalizations and decreased nociceptive responses. In Expt. 1, habituation to the test chamber attenuated stress-induced analgesia but did not affect distress vocalizations. In Expt. 2, placement of mirrors in the test chamber attenuated distress vocalizations but did not affect stress-induced analgesia. These findings demonstrate a dissociation of stress behaviors in the chick social-separation-stress procedure: the stress-induced analgesia response is primarily mediated by novelty to the test apparatus while the distress vocalizations response is mediated by separation from conspecifics.

The purpose of the present study was to determine the strength and persistence of cocaine-induced conditioned activity in young and adult rats. A one-trial protocol has proven useful for studying the ontogeny of psychostimulant-induced behavioral sensitization; therefore, a similar procedure was used to examine conditioned activity. On postnatal day (PD) 19 or PD 80, rats were injected with saline or cocaine in either a novel test chamber or the home cage. After various drug abstinence intervals (1–21 days), rats were injected with saline and returned to the test chamber, where conditioned activity was assessed. In a separate experiment, we examined whether cocaine-induced conditioned activity was a consequence of Pavlovian conditioning or a failure to habituate to the test environment. The results showed that adult rats exhibited strong one-trial conditioned activity that persisted for at least 21 days, whereas young rats did not show a conditioned locomotor response. The conditioned activity exhibited by adult rats did not result from a failure to habituate to the cocaine-paired environment. These results indicate that cocaine-paired contextual stimuli differentially affect behavior depending on age of the animal. The data provided by adult rats have potential translational relevance for humans because a single environment-drug pairing caused long-term alterations in behavior.

Previous studies have shown that preweanling rat pups double or triple their rates of ultrasonic vocalization (USV) when isolated immediately after brief periods of maternal interaction (potentiation). We studied the ontogenetic pattern of USV and other behavioral responses of pups to 3-min periods of isolation in a novel test chamber, from 5 to 25 days postnatal age, before, during, and after 1 min or 5 min of interaction with an anesthetized or an active dam. USV potentiation did not develop until 7-9 days postnatal, a week after the initial isolation and maternal contact quieting responses were well established. Potentiation reached a peak at 13 days, and then declined until all USV responses ceased after 21 days. Other behavioral responses to isolation were not enhanced by maternal interaction at any age. The distinct ontogenetic pattern of this unusual response to maternal separation has implications for understanding its mode of development and possible adaptive value.

The developmental course and behavioral processes by which infant rats come to prefer one of two prominent natural odors within their rearing environment, those of their mother and home nest shavings, was studied. Pups as young as 4–5 days and as old as 9–10 days prefer their mother's odor over that of their home nest shavings in a two-choice test chamber; pups deprived overnight prior to testing express that preference more strongly than nondeprived littermates when the mother is awake, but not when anesthetized. Encountering maternal and shavings odors in a two-choice paradigm engages a behavioral sequence that progresses from arousal and active sampling of both odors during the establishment of preference to increased mouthing after the choice has been made. A .5°C thermal gradient augments the maternal preference response from 4–5 days of age on, and is necessary to it in 2-day-olds. One-day-old pups do not express a preference for their mothers in our test apparatus on the basis of odor even with the addition of a .5°C thermal gradient, suggesting that preference for the odor of mother over home shavings may be acquired between 1 and 2 days of age. © 1998 John Wiley & Sons, Inc. Dev Psychobiol 33: 5–20, 1998

Adult rats often produce 50-kHz ultrasonic vocalizations (USVs), particularly the frequency-modulated varieties, in appetitive situations. These calls are thought by some to reflect positive affective states and the reinforcing value of drugs such as amphetamine and cocaine. The objective of this study was to determine whether the number of unconditioned 50-kHz USVs elicited by amphetamine predicts the development and/or magnitude of drug-conditioned motivation. In three experiments, we recorded USVs before and after injections of 1 mg/kg amphetamine (i.v. or i.p.) administered once per session. Rats were categorized as “high callers” or “low callers” according to individual differences in the number of 50-kHz USVs elicited by their first amphetamine injection. We examined the conditioned appetitive behavior and conditioned place preference (CPP) that emerged in high and low callers after repeated pairings of amphetamine with specific contexts. We also examined whether amphetamine-induced calling was affected by treatment within an unfamiliar (test chamber) versus familiar (home cage) context. Within an unfamiliar environment, the high callers consistently produced more amphetamine-induced 50-kHz USVs than the low callers. Compared to the low callers, high callers showed significantly greater amphetamine CPP as well as enhanced conditioned 50-kHz USVs and locomotor activity during anticipation of amphetamine. Individual differences were stable when amphetamine was administered in test chambers, but when it was administered in home cages, low callers showed an increase in 50-kHz calling that matched the high callers. These findings suggest that individual differences in drug-induced USVs can reveal environment-sensitive traits involved in drug-related appetitive motivation.

Animal models can be used to contribute to understanding the information about molecular mechanisms involved in anxiety and for screening and developing new medications for their treatment that would be impossible in humans. The human studies have established the genetic basis of anxiety and animal studies have been used to attempt to further clarify its genetic determinants. In the field of anxiety research, animal models can be grouped into two main classes. The first involves the animal's conditioned responses to stressful and often painful events (e.g. exposure to electric foot shock) and the second includes ethologically based paradigms and involves the animal's spontaneous or natural reactions (e.g. flight, avoidance and freezing) to stress stimuli that do not explicitly involve pain or discomfort (e.g. exposure to a novel highly illuminated test chamber or to a predator). The current review enlightens the various aspects of animal model of anxiety, which may be used for research purpose.

Since their discovery in 1956, the highest rates of ultrasonic vocalization (USV) have been recorded from infant rats when first isolated in an unfamiliar place. We now report that peak USV rates can be doubled by allowing test pups a brief initial period of contact with their anesthetized dam (1–10 min) in the test chamber before isolating the pup by her removal. Potentiation of the isolation response was specific to the dam, for it failed to occur following initial contact with a group of 4 warm, anesthetized littermates. Control experiments showed that potentiation could not be attributed to thermal contrast, experimenter handling, general behavioral activation, novelty of maternal cues, or nursing deprivation. Furthermore, it did not occur when pups were taken for isolation testing directly from prolonged contact with their anesthetized dam in the home cage. Potentiation may be understood in terms of the communicative role of the pups' call and/or prior learning contingencies within the mother–infant interaction.©1994 John Wiley & Sons, Inc.

Abstract. Male chickens produce characteristic pulsatile calls upon discovering food and are more likely to call in the presence of a hen. Calling thus appears to be dependent upon food and to be modulated by social context. An alternative explanation is that food calls are in fact components of a complex courtship display. The relationships between food calling, food availability and courtship were examined in a laboratory setting. Subjects interacted with an unfamiliar hen and were then given access to food, using an instrumental conditioning procedure. In some control conditions, the males were tested alone, while in others food was unavailable. Food calling, sexual display and the rate at which males performed an operant response were measured. Call production increased dramatically when food first became available, both when a hen was present and when males were alone. This change in call rate did not occur during control trials without food. Sexual display was maximal when males were first placed in the test chamber with a hen present and declined exponentially thereafter. The presence of a hen had no effect on food calling during this period. Food calling was thus principally elicited by food stimuli and was not reliably associated with courtship behaviour. When a hen was present, males called at a higher rate following food presentations. In contrast the rate at which males worked to obtain food was unaffected by social context. The 'audience' effect therefore acts specifically to potentiate calling and is distinct from social facilitation.

We investigated whether capuchin monkeys (Cebus apella) would choose to observe a high- or low-status adult female from their group during experimental foraging tests. The subject was located in the center of a test chamber, with a low- and high-ranking demonstrator on either side of two partitions. A peephole allowed the subject to observe the models by looking through either respective partition. Each model was trained on one of the two different methods, lift or pull, for retrieving food from a foraging apparatus. There were 22 subjects and four models. During the 40-trial test sessions, subjects could choose which model they would watch in each trial. It was predicted that subjects would prefer observing the model with whom it was closer in rank, and therefore share greater affiliation with. Results showed that only half the subjects showed a preference and that preference was not linked to status. Relatedness played a larger role in determining if a subject showed a preference for a model, and a correlation was found for relatedness and observer preference. After the observer preference tests, subjects were presented with the foraging apparatus to determine if they displayed a preference for one of the two tasks. The majority of subjects (17/22) showed a preference for the pull method, suggesting that this method may have been more salient to the monkeys in this study. Am. J. Primatol. 73:920–927, 2011. © 2011 Wiley-Liss, Inc.

The effects of repeated systemic or intra-nucleus accumbens cocaine administration on locomotor activity were examined for environmental dependence. Repeated IP administration of cocaine (15 mg/kg) for 5 days in the context of a given environment increased the locomotor response to a subsequent IP cocaine challenge in that environment. However, there were no differences in the locomotor response to a subsequent IP cocaine challenge in the test chamber in subjects which had received prior repeated IP administration of cocaine in the home-cage. In a second experiment, cocaine (100 micrograms/side) was infused into the nucleus accumbens (NACC) daily for 5 days. This repeated administration produced increases in locomotor activity to subsequent intra-NACC cocaine infusions that were environmentally independent. In contrast to the effects of repeated IP cocaine administration, subjects which received administration of vehicle, acute cocaine, or repeated cocaine in the NACC did not differ following an IP cocaine challenge. The results from these experiments indicate that increases in the response to IP cocaine following repeated IP administration are in part environmentally dependent. Moreover, repeated intra-NACC cocaine infusions increase the responsiveness of the NACC to subsequent intra-NACC cocaine. However, local activation of the NACC alone does not appear to be adequate to produce sensitization to systemically administered cocaine.

Yohimbine HCl, an antagonist at alpha 2-noradrenaline receptors with putative panicogenic effects in human subjects, was administered to Swiss-Webster mice at doses of 0.5, 1.0, and 2.0 mg/kg. Animals were then tested in two defense test batteries. Yohimbine produced increases in flight from an approaching/contacting human and potentiated animals' reactions to dorsal contact. During a 5-min exposure to a cat (separated from the mouse by a wire-mesh screen) and the 15-min period thereafter, yohimbine produced a dose-dependent pattern of changes in defensive behaviors that included increases in locomotion, transits from one segment of the test chamber to another, fore- and hindpaw wall climbing, screen climbing and hanging, and roof pushing. Crouching (relative immobility while in a hunched-back posture) was notably decreased at all doses. During the postcat period, two different response patterns, "high-escape" and "low-escape," characterized in part by high and low frequencies of wall climbing, were observed in cat-exposed groups. In yohimbine-injected mice, the low-escape behavior pattern also included a tendency to avoid the segment of the test chamber closest to the cat compartment. Both patterns differed from the crouching and immobility generally exhibited by vehicle-injected, cat-exposed controls. It was suggested that yohimbine effected these behavioral changes by either potentiating neural mechanisms mediating flight or inhibiting mechanisms mediating freezing. This model may have some utility for the investigation of panicogenic and antipanic compounds and may contribute insights into the etiology of panic disorder.

Transient global ischaemia induces cell death in the CA1 layer of the hippocampus. To evaluate the functional consequences, we performed context-dependent fear conditioning. Ischaemia was induced by 2-vessel-occlusion (2VO) in gerbils. On day 6 post ischaemia or sham procedures (in control group) gerbils were placed in a test chamber and after 3 min adaption time exposed to foot-shocks (training session). On the next day the animals were placed in the same test chamber without foot-shocks (test session). As a parameter for memory performance we used the standard method of measuring the total freezing time via a cumulative time-sampling procedure during the test session. We found a significant longer total freezing time in control animals than in ischaemic animals. In addition, however, we applied a more detailed analysis of (i) quantifying the number of freezing bouts, (ii) the average duration of single freezing bouts, (iii) the activity pattern during the training and test situation and (iv) we differentially evaluated all the single time segments of the experiment. These analyses revealed that although maintenance of freezing (duration of freezing bout) was significantly lower in ischaemic animals compared to controls, the initiation of freezing (number of freezing bouts) was not significantly different between the two groups during the test session. The activity scores of ischaemic and non-ischaemic gerbils were similar during the adaption time of the training session. The foot-shock, however, induced a significantly different pattern of behaviour in the ischaemic animals, which was selectively reproduced during the test session. In conclusion, ischaemic gerbils reacted to a fearsome thread with a behavioural pattern different from unlesioned animals and they revealed this specific foot-shock induced behaviour again during the test session. This indicated that CA1 hippocampal death did not interrupt memory performance but changed expression of fear. Therefore, measuring duration of freezing and the activity score seems to be not applicable for quantitative comparisons of memory deficits after 2VO in gerbils in a context-dependent fear conditioning task. Our results indicate, however, that initiation of freezing (number of freezing bouts) may be a more suitable parameter comparing gerbils with and without CA1 damage.

40 male and 40 female Wistar-Imamichi rats were observed for their defensive burying and related behaviors in a novel or a living situation. In the novel situation, each rat was preexposed to a novel test chamber for 30-min on four consecutive days. In the living situation, each rat lived in the same chamber for nine days. On the next day of these preexposures, a shock prod was inserted into the chamber. Rats in the novel situation engaged in prod burying more than rats in the living situation, which showed less burying, more prod exploring, and more grooming. Female rats more engaged in burying than male rats in both situations. It is suggested that lower fear level of the rats due to full habituation to the living chamber may suppress the fear to the shock prod and burying behavior.

Human adolescents drink partly to facilitate their social interactions, a social facilitatory effect of ethanol also seen in adolescent rats tested under familiar test circumstances. To explore the role of hedonic affect in ethanol-induced social facilitation, this study assessed 50 kHz ultrasonic vocalizations (USVs) in pair-housed adolescent (P29-37) and adult (P71-79) Sprague-Dawley male rats during social interactions. On each of eight test days, animals were socially isolated for 3 h and then injected intraperitoneally with 0 (saline), 0.25 or 0.5 g/kg ethanol. Twenty-five minutes later they were placed alone in a familiar test chamber for a 5-min period, followed by a 10-min encounter with a similarly injected peer. USVs were recorded during this 10-min period, while social interactions were videotaped for later scoring. BECs were measured immediately post-test on day 8. Although the 0.25 g/kg dose of ethanol facilitated play fighting in adolescents but not adults, ethanol had little to no effect on 50 kHz USV production under these test circumstances. USV production was higher in adults than adolescents, despite adolescents consistently engaging in more social behavior. To the extent that 50 kHz USVs index the hedonic value of social interactions, these findings support the conclusion that elevations in social behavior normally evident in adolescents may not be related to increases in hedonic sensitivity for social stimuli.

In Experiment 1, four groups of male rats were given a session as an intruder in either aggressive (i.e., alpha) or nonaggressive colonies of conspecifics and later received either a 2-h exposure to the odors of the alpha colonies or an exposure-control session with the odors of a nonalpha colony. Two additional groups of rats that had been attacked and defeated by alpha residents were later given a 12-h exposure session with alpha-colony odors or nonaipha-control odors. Twenty-four h after the colony-intruder session, all subjects were given a single 6.5-mA shock from a prod with alpha-colony odors present in the bedding of the test chamber. Attacked rats that had been given exposure-control sessions showed significantly less prod burying and greater freezing than nondefeated subjects. This implies that the alpha-colony odors elicited conditioned fear. In contrast, the attacked subjects that had been given a pretest exposure session with alpha-colony odors showed significantly more prod burying and significantly less freezing. This suggests that the alpha-odor exposure resulted in the extinction of fear to these odors. Furthermore, the 12-h exposure to alpha-colony odors was found to be more effective in reducing fear-mediated responses than was the 2-h exposure. In Experiment 2, three groups of rats were exposed to a cat while they were in a protective cage; later they were given a 12-h exposure session with cat odors, a 12-h exposure-control session with no cat odors, or no exposure treatment. Compared with the two control groups, the subjects that were exposed to cat odors showed less freezing during subsequent prod-shock tests in the presence of cat odors, but they did not show prod burying. The reported changes in fear-mediated reactions to the odors of conspecifics and a predator are discussed in terms of both associative and nonassociative processes.

Rats were trained on either of two related variants of an operant memory task. In the matching to position (MTP) task, one of two retractable response levers appeared, at random, as the sample. A response caused the lever to retract and this was followed by a delay (0-32 s) interval, during which the subjects had to approach and respond at the magazine tray. Both levers were then presented and the rat had to respond, for food reward, to the one which had appeared as the sample. A second group of rats learned non-matching to position (NMTP). This task was very similar to MTP, with one crucial difference: here, the subject had to respond to the lever which had not appeared as the sample. Both groups of rats learned their respective tasks rapidly, performance depending on the delay interval as expected. They were then injected, peripherally, with different doses of arginine-vasopressin (AVP: 0-25 micrograms/kg), a peptide which others have argued improves mnemonic performance. There was evidence to suggest that MTP performance was improved by AVP; on the other hand, NMTP performance appeared to be disrupted. It is suggested that AVP induces a bias towards responding on one side of the two lever test chamber. In other words, it affects motor or motivational, not mnemonic mechanisms.

This study aimed to identify the ontogenetic period during which long-term expression of behavioral sensitization to cocaine begins to emerge. Rat pups aged 4, 8, 12, or 16 days received a pretreatment of 4 daily injections of 15 mg/kg sc cocaine paired with the test chamber for 45 min. Pups were then tested for sensitization in that context after abstinence intervals ranging from 2 to 10 days. On test days, pups were videotaped, and their behavior was scored later. Sensitization was detected after intervals of 2, 4, 5, or 9 days in pups aged 4-7, 8-11, 12-15, or 16-19 days during pretreatment, respectively. These results suggest that the mechanisms for long-term retention of sensitization mature incrementally in the rat, starting to emerge gradually after the 1st week of age, whereas those relevant to short-term retention and initiation of sensitization are present earlier.

Before entering the complex field of behavioral monitoring one has to consider biological functions of behavior. Behavior has to do with ecological adaptation of organisms to their environment, and with the intra- and extraspecific interactions of individuals. There are many different purposes of behavior, which is determined by evolution. The most organisms have innate behavior mechanisms which allow them to adapt to almost every situation occurring in their life and environment. The more subtle these mechanisms are differentiated, connected with a higher flexibility of reactions, the more the animal will be successful in its struggle for life, even under changing environmental conditions. These innate behavior mechanisms are permanent under evolutionary selection. The differences between “fixed action patterns” in the sense of Lorenz (1950) and “modes of action patterns” in the sense of Marler and Hamilton(1960) will not be discussed here.Barlow (1968) argues: “if the fixed action pattern is to be used to generate models of use to the neurophysiologist, we must examine it closely to see if it qualifies as a basic unit of behavior”.One of this criteria to answer this question is to analyze if there is a variability in the pattern. The behavior patterns we can use for behavioral monitoring have all the certain range of variability. So we like to follow the suggestion of Barlow: “It might be wise to drop the term fixed from the action pattern.”

Female rats "pace" their sexual contacts with the male when tested in situations where they can escape from the male during copulation. The type and quality of vaginocervical stimulation that the females receive during copulation influences their pacing behavior. This study investigated the effect of several male-related stimuli on the female's postejaculatory refractory period (PER). Females were tested in a two-compartment test chamber from which they could escape the male through one of four openings along the bottom of the barrier separating the two compartments. Experiment 1 examined the influence of the seminal plug, the penile cup, and prostate secretions on the female's PER. Results showed that neither the seminal plug, the penile cup, nor prostate secretions contributed to the female's PER. Experiment 2 investigated the relation of pre-ejaculatory intromission frequency, ejaculation duration, and the number of pelvic thrusts during ejaculation to the female's PER. Results indicated that pre-ejaculatory intromission frequency and ejaculation duration but not the number of pelvic thrusts during ejaculation were significantly correlated with the female's PER. In addition, pre-ejaculatory intromission frequency was significantly correlated with ejaculation duration. Partial correlation analysis suggested that pre-ejaculatory intromission frequency affected ejaculation duration which, in turn, influenced the female's PER. This finding was further supported by the evidence that ejaculation duration and the female's PER were significantly shorter in tests in which the male ejaculated on the first or second intromission.

Encoding the spatial location and the time at which significant biological events occur is thought to be a fundamental way in which memory is organized in animals. Some field data on gulls' foraging behavior suggests that time-place behavior may consist of a conditional discrimination. In this study gulls flew at sunrise to locations containing earth worms, but only after rainfall. The purpose of the present research was to attempt to demonstrate conditional time-place learning in the laboratory. Pigeons were trained to visit three sites successively in two different orders that were signaled by room and test chamber cues. The pigeons successfully learned the task, supporting the notion that time-place foraging behavior can be modulated by other environmental regularities.

A freely walking single fly (Drosophila melanogaster) can be conditioned to avoid one side of a small test chamber if the chamber is heated whenever the fly enters this side. In a subsequent memory test without heat it keeps avoiding the heat-associated side. The memory mutants dunce 1 and rutabaga 1 successfully avoid the heated side but show no avoidance in the memory test. Wildtype flies can be trained to successively avoid alternating sides in a reversal conditioning experiment. Every single fly shows strong avoidance and a positive memory score. The new conditioning apparatus has several advantages: (1) Statistically significant learning scores can be obtained for individual flies. (2) Learning scores are obtained fully automatically without interference of the experimenter. (3) The procedure is fast, robust and requires little handling. Therefore the apparatus is suitable for largescale mutant screening. (4) Animals are not attached to a hook and thus can easily be used for breeding.

Enucleated juvenile rats were compared to sighted juveniles, and tested over six trials. In some of these trials, the vibrissae were clipped and the test chamber was flooded with white noise. Even though the enucleated rats played, they did so in an atypical manner. They tended to initiate more playful and other social contacts, and were more likely to defend themselves if contacted. When they did defend themselves, they adopted behavior patterns that were more likely to evade the partner's attack. In addition, the enucleated rats were hypersensitive to the partner, being more likely to respond defensively when contacted further from the nape (the main play target). All these changes in play fighting by nonsighted rats suggest that the loss of vision leads to motivational changes in activity and reactivity, and so has an indirect effect on play behavior. In addition, direct evidence is also provided to show that vision is used to orient attacks to the nape. When the vibrissae were closely clipped, the sighted rats continued to make direct attacks on the partner's napes, whereas the nonsighted rats did not. Rather, they first contacted some other part of the partner's body and then oriented to the nape. Another test paradigm was used to determine whether vision is used to trigger defensive responses. The rats were partially food deprived as adults and were filmed in a food wrenching and dodging situation where one rat was given a food pellet and the other allowed to steal it. Measurement of the distance at initiation of the lateral swerve away from the approaching partner (i.e., dodge) showed that when the vibrissae are clipped, the sighted rats continued to initiate dodges at the same distance, whereas the nonsighted rats could not. Therefore, vision appears to have an active role in organizing movement sequences of attack and defense in play fighting and other close-quarter interactions.

This study looked at the effects of neonatal cocaine exposure on activity rhythms over a 48-h period in rats. Subjects were artificially-reared from postnatal days (PN) 4-10 via intragastric cannulas. The four treatment groups included two cocaine doses (20 and 40 mg/kg per day), an artificially-reared control and a normally reared suckled control. Subjects were tested at PN 38-40 in an automated running wheel. Neonatal cocaine exposure did not alter activity rhythms over the 48-h test period. However, there was a gender-specific effect of neonatal cocaine exposure on response to the novel test chamber and to the experimenter. The 20 mg/kg cocaine-exposed females showed increased running wheel activity relative to all other groups after placement in the running wheel. During the second 24-h period, cocaine-exposed females from both cocaine groups showed increased activity relative to controls following the entry of an experimenter to the test room. These findings suggest that female rats exposed to cocaine neonatally show an increased response to novel environments and stimuli.

Summary.-Ethanol may play an active role in modifying "set point" levels in conjunction with behavioral thermoregulation. A geometric series of doses of ethanol solutions was administered (ip) prior to fiied-interval 2-min. schedules of microwave reinforcement in rats tested in a cold environment. Four Sprague-Dawley rats were conditioned to regulate their thermal environment with 5-sec. exposures of MW reinforcement. Friedman's nonparametric test showed significant differences between ethanol doses, and Sign tests showed that moderate and high doses of ethanol suppressed operant behavior reinforced by MW radiation. Interactions between changes in "setpoint" and discriminative properties of ethanol are discussed. Alcohol is classified as a central nervous system depressant, the behavioral consequences of which are comparable in many respects to those produced by the benzodiazepines and barbiturates (Hamilton & Timmons, 1990). This study concerned the thermoregulatory influence of alcohol in modifying operant behavior. If alcohol functions to lower hypothalamic "set point," then organisms should behave in such a way as to "seek" coolness; and if alcohol functions to raise "set point," then organisms should work to increase heat, to achieve homeostasis. For example, O'Comer, Crawshaw, Kosobud, Bedichek, and Crabbe (1989) found that in mice, moderate doses of ethanol decreased "set-point" so that mice "selected" cooler temperatures. They used an "aquatic temperature gradient" to control ambient fluctuations. The present study was designed to test the "set-point" hypothesis in rats working in a cool environment and regulating their body temperature by operant adjustments of microwave radiation (MW). Detailed descriptions of the methods used to enable rats to warm themselves with MW radiation in a cold operant test chamber (Skinner Box) have been published (Vitulli, Mort, Quim, LosKamp, & Dodson, 1986; Vitdi, Lambert, Brown, & Quinn, 1987; Vituh, Tyler, Hartzog, & Quinn, 1989; Vitulh, Anderson, Quinn, & Jarvis, 1990; Vitulli, Rust, Quinn, & McNeil, 1991). Four Sprague-Dawley rats (males) approximately 8 mo. of age at the beginning of the research were randomly sampled from a population of rats who had received lever-conditioning for food reinforcement in a class in operant conditioning. The mean ad libitum weight for all animals was 580 gm. (SD = 62.97). The animals were conditioned in a Skinner Box on a fixed-interval 2-min. (FI-2') schedule of microwave (SAR = ,034 watts/kg/(m~/cmz ) reinforcement (5

The present experiment examined rats' responding maintained by a fixed interval two-min schedule of food reinforcement following IP injections of bombesin (4, 6, 16, 32 μg/kg). The results showed that bombesin's effects were rate dependent where the responses per minute emitted during the early portion of the fixed interval were reduced, but responding during the latter portion was unaffected. Bombesin did not reduce overall session responses per minute, pause after reinforcement, or amount of water consumed in the test chamber. The results are in accord with prior research examining the effects of bombesin and cholecystokinin on operant behavior. Together, the data challenge the notion that bombesin affects food-motivated behavior generally; rather, the results indicate that bombesin's effect may interact with the demands required of the animal for reinforcement.

Rats habituated to DRL 6-s schedules that required response inhibition in order to obtain reward did not alter their total responses or efficiency ratios (response/reinforcement) when placed ad libitum (orally) on 0.9% taurine (1.1 +/- 0.4 g/kg/24-h) relative to controls. In three separate experiments, taurine-administerd rats did show significantly poorer adjustment profiles (higher response/reinforcement ratios) during the 15 min immediately following step-like increases in inhibition time demand to DRL 12 s. The effect was transient and was not signficant in subsequent sessions. Taurine rats had been habituated to a DRL schedule intended to induce "frustration" before and step-change did not differ from the taurine group maintained on the normal DRL schedule. No significant differences were noted between taurine and control groups, either before or after taurine administration or before or after the step-change in inhibition demand, with respect to defecation in the test chamber, daily fluid consumption, body weight or total responses. We concluded that oral taurine may inhibit learning during labile periods of adjustment following sudden changes of input demand but does not influence a well learned or established response pattern. These results imply taurine's role in the brain as a "stabilizer" against short-term input fluctuations.

Four experiments are reported in which it is shown that elderly adults are more prone than young adults to olfactory adaptation and are slower to recover threshold sensitivity. The first three experiments differed in detail, but had in common an initial threshold determination for 1-butanol, a 30 s exposure to a concentration twenty-seven times threshold, followed by repeated presentation of the initial threshold level at various intervals after adaptation. In three experiments accuracy of forced-choice discrimination was poor immediately after adaptation but tended to improve with time, and considerably faster in the young than in the elderly. In the fourth experiment, groups of twenty-three elderly and twenty-five young subjects threshold-matched for pyridine were compared. The subjects participated in three sessions in which pyridine was infused into a test chamber at either 2.5, 1.25, or 0 L min−1 (sham session). At 2.5 L min−1 both groups were able to track the buildup of odor intensity during infusion and its decline after infusion. In contrast, at 1.25 L min−1 only the young were able to track odor intensity, even though the concentration rose above initial threshold levels.

Rats shocked once by a stationary, wire-wrapped prod mounted on the wall of the test chamber incorporated sand, wooden blocks, or commercial bedding material on the floor of the chamber into a defensive response. They moved the available material toward and over the shock prod in all three conditions, adapting the response topography to the particular demands of the available material. In the sand and bedding conditions, the rats buried the prod by pushing and spraying piles of the material with snout and forepaws, whereas, in the blocks condition they picked up the blocks with their teeth and placed them individually around the prod. In Experiment 2, the rats buried the shock prod with blocks even when they had to first carry the blocks to the prod from the back of the chamber. Thus, conditioned defensive burying is not a simple, reflexive response to objects paired with a painful stimulus: it is a complex behavioral sequence that can vary as a function of the availability of burying materials.

Two strains of rats (albino Wistar and hooded PVG/c) were exposed to a conditioned defensive burying paradigm that consisted of placing rats in a test chamber with bedding material on the floor, shocking them with a shock prod, and recording the time each rat spent in burying responses toward the prod. Various behaviors other than burying (freezing, grooming/paw licking) were observed by a time-sampling procedure during the control, conditioning, and extinction sessions, each of which was 15 min in duration. Wistar rats generally showed behavioral inhibition, as evidenced by less burying, lower exploratory and ambulatory behavior, and higher freezing behavior. PVG/c rats spent significantly more time engaged in burying and accumulated more bedding material in the conditioning session than did the Wistar rats. No significant differences between the two strains of rats were observed during the extinction session in terms of these measurements. The results indicate that Wistar rats have a greater tendency to freeze when coping with the noxious stimulus in a conditioned defensive burying paradigm, whereas the dominant coping style for PVG/c rats is defensive burying.

Six water-deprived pigeons were exposed to a fixed-time 90-sec water schedule with and without a conspecific target available. Target contacts and the pigeon’s location in the test chamber during the interreinforcement interval were recorded, and the results were compared with those previously obtained with food reinforcement. Prior to target introduction, water-reinforced birds spent more total time in the front near the reinforcer dispenser and less in the rear than food-reinforced birds and, unlike food-reinforced birds, exhibited postreinforcement drinking-like behaviors near the reinforcer dispenser before moving away from that area. With the target available, the level, topography, and duration of target-directed biting pecks were comparable for food- and water-reinforced pigeons. In contrast, the temporal organization of target pecks reflected the different temporal and spatial organizations of behavior prior to target introduction. For both food- and water-reinforced birds, the time between reinforcers at which a bird was spatially situated halfway between the front and rear of the chamber prior to target presentation was positively correlated with the time at which maximum target contact subsequently occurred.

Rats (Rattus norvegicus) deprived of the opportunity to interact with particulate matter until they were young adults engaged in defensive burying after they were shocked by a wire-wrapped dowel in a test chamber that held bedding material. Interacting with a particulate substrate during development is not necessary for the expression of defensive burying in adulthood. However, interacting with a particulate substrate early in the rats' lives did have a substantial effect on the emergence and maintenance of burying behavior. Defensive burying developed at a later age and declined at an earlier age in rats maintained on wire mesh from birth until testing than it did in rats raised until weaning on bedding and housed on mesh thereafter. Because defensive burying is a complex, flexible, yet reliable response sequence that cannot be performed without the appropriate substrate, it has considerable potential as a model for the study of the development of species-specific defense responses.

Thirsty rats, permitted to drink a novel tasting solution (decaffeinated coffee) followed immediately by 15 min of intracranial self-stimulation (ICSS), subsequently demonstrate a preference for that novel solution. After one coffee-ICSS pairing, the preference for coffee over water in a free-choice situation was demonstrated both in the test chamber, where the pairing occurred, and in the home cage. Increases in the number of coffee-ICSS pairings, however, resulted in smaller coffee preferences in the home cage and larger preferences in the test chamber. It was suggested that as the novelty of the coffee solution decreased, the relative salience of other test chamber exteroceptive stimuli increased. After repeated coffee-ICSS pairings, therefore, the rats were responding not to the presence of coffee alone, but rather to the presence of a compound stimulus of which coffee was a part. These data therefore demonstrate the importance of exteroceptive stimuli for the demonstration of conditioned taste preferences induced by self-stimulation.

Rats shocked once through a wire-wrapped stationary prod mounted on the wall of a test chamber incorporated the bedding material covering the chamber floor into a defensive reaction. When tested 1 min later, they approached the prod and buried it. Evidence was provided by three separate studies of this burying response that rats had learned about the association of both the position and brightness of the prod with shock after this single conditioning trial. In Experiment 1, the amount of burying decreased if either the position or brightness of the prod had been changed prior to the test. In Experiments 2 and 3, rats were shocked through one of two prods (white or black) mounted on opposite walls of the test chamber. When the positions of the prods were unchanged for the test, almost every subject buried the prod through which it had been shocked, even when the conditioning-test interval was 24 hr; whereas, each rat directed substantial amounts of bedding material at both prods when the positions of the two prods were reversed. Thus, discriminated “avoidance” learning can be rapid, reliable, and enduring when shock is administered “by” a clearly defined stimulus object, i.e., when cue and consequence are spatially contiguous.

Time spent in various behaviors by the rat was recorded in a defensive burying paradigm. Experiment 1 revealed that rats spent more time burying the shock prod than a control prod and that doubling the size of the test chamber did not have a significant effect on the time spent in any behavior. In Experiment 2, the location of bedding material in a two-compartment test chamber was found to affect the occurrence of burying (both the shock and control prods) and burrowing behavior. Burying did not occur when bedding was not available in the shock compartment but was located in the escape compartment. Burrowing was more likely to occur when bedding was in both compartments than when it was in only one compartment. Immobility and escape latencies were shorter than burying latencies in all subjects. Burying was viewed as belonging to a second stage of defensive behavior.

Genotypically based within-species differences in defensive burying were examined in 180 mice representing 15 inbred strains. Each mouse was tested twice in a cylindrical test chamber containing two similar prods. In the first test, one of the prods was electrified, whereas in the second test (24 h later), neither prod was. Although most strains selectively buried the shock prod in the first test (as determined by bedding-height-at-prod and position-of-highest-bedding-pile criteria), some strains did not discriminate between the shock and dummy prods and still others displayed little prod-directed bedding displacement at all (thereby resembling a heterogeneous nonshocked control group). In general, burying tended to be somewhat reduced in the second test, but strain differences in retention were observed. Factors contributory to the observed differences among strains and the need for multiple measures of burying are discussed. Collectively, these findings indicate that intraspecific genetic variation, acting at multiple burying-relevant behavioral levels, can be an important determinant of the expression of the defensive-burying response in mice.

The behavioral CRs elicited by a drug-paired contextual cue in rats were measured in a series of experiments. The first three experiments measured the pattern of CRs elicited by a lithiumand an amphetamine-paired CS chamber. The final experiment measured the pattern of URs elicited by lithium or amphetamine when administered in the same chamber. The suppression of grooming-related activities (body washing, face washing, and/or scratching) appeared as a nonspecific effect of both drug USs that was capable of becoming conditioned to the contextual chamber cue. A number of other behaviors differed among conditions, which provides evidence that contextual cue-drug associations are drug-specific. Of the behaviors that differed between the two US drug conditions, lithium CRs showed evidence of behavioral activation (enhanced rearing and limb flicking), but amphetamine CRs showed evidence of behavioral suppression (line crossing, rearing, and shaking). The UR patterns shared some similar and some dissimilar elements of the CR patterns elicited by the CS chamber for both lithium and amphetamine; in fact, by the activity and rearing measures, the URs and CRs were opposite in direction. The results exclusively supported neither stimulus substitution nor conditioned compensatory response accounts of Pavlovian conditioning; instead, each process appears to have accounted for different components of the overall CR pattern.

Rats were trained to leverpress in a conventional operant test chamber; however, their behavior was rewarded solely by social interaction with a human being. This training was successful for half the subjects tested; success was confined to animals for which social interaction had occurred prior to training. Similar findings with other species are discussed. Although the effects of social interaction with a human are by no means as robust as those of food to a hungry animal, the present results suggest that the human-rat interaction may be a positive adjunct to conventional behavioral training techniques, and a possible confound where its effects are uncontrolled.

Two experiments examined the possibility that presenting hungry rats with noncontingent food would interfere with the acquisition of instrumental responding for food reward. In Experiment 1 groups of rats received 0, 1, 10, or 20 50-min sessions, during which Noyes pellets were presented noncontingently on a variable time (VT) 60-sec schedule, and were subsequently trained to barpress for food reward. All three groups that received noncontingent food acquired instrumental responding for food reward more rapidly than the 0-session controls, but there was no indication that 10 or 20 sessions of exposure to noncontingent food produced slower acquisition of the instrumental response than 1 session. In Experiment 2 two groups were exposed to 1 or 30 1-h sessions, with food delivered on a VT 60-sec schedule. A third group lived 24 h/day in operant chambers for 15 days; food was delivered noncontingently on a VT 6-min schedule throughout the day. The latter group was then given a single 1-h session in the test chamber with food delivered noncontingently on a VT 60-sec schedule. During tests of instrumental responding for food, all three groups acquired the barpress response at similar rates. The present experiments fail to confirm earlier reports that prior exposure to noncontingent food impairs subsequent acquisition of food-rewarded responding by rats.

Attempts to establish the generality of the defensive-burying response have proved quite successful with several strains of albino and hooded rats and with mice. However, three previous attempts to demonstrate this behavior in gerbils have been completely unsuccessful. Three additional defensive-burying experiments employing gerbils as subjects are reported. Defensive burying did not occur when testing took place in a rectangular chamber (Experiments 1 and 3), but did occur when a circular chamber was employed (Experiments 2 and 3). Hence, the geometric shape of the test chamber appears to be a crucial factor in determining the elicitation of this behavior in gerbils. Furthermore, the overall topography of the gerbil defensive-burying response was found to be different from that of previously examined species.

Pigeons were trained on a variant of the autoshaping procedure in which a keylight stimulus of increasing brightness was used to signal the passing of a 30-sec interfood interval (IFI). Key-pecking developed in all subjects within the first session (65 trials). Within trials, pecking began midway through the IFI, increased throughout the remainder, and decreased just before food delivery. Other behavioral stereotypies were also recorded: Low light levels were associated with a retreat to the rear of the test chamber, and medium light levels (during the midportion of the IFI) were associated with high rates of pacing toward and away from the food source. Probe trials revealed that pecking, pacing, and retreat were all under strong stimulus control; that is, when the light was held constant at its lowest or highest brightness, or when the brightness ramp was presented in reverse order, the behavior pattern almost invariably remained tied to stimulus brightness. Results are discussed in terms of associative and nonassociative sources of the form and sequential characteristics of the behavior.

Rats shocked once by a stationary, wire-wrapped prod bury it if suitable materials are available. Does this conditioned defensive burying occur when rats have the opportunity to flee from the source of aversive stimulation, or is it limited to situations such as those in which it had previously been studied—those in which the relatively small test chamber confined each rat to the immediate vicinity of the prod? In the present experiments, the capacity of rats to flee from the shock prod was enhanced by increasing the floor dimensions of the test chamber up to 200X80 cm (Experiment 1) or by providing the rats with an opportunity to seek refuge in a separate, safe compartment (Experiment 2). Although both of these modifications to the usual conditioned-defensive-burying paradigm significantly reduced the duration of burying and the height of the accumulated mounds, burying remained well above control levels in all experimental conditions.