Punishment of consummatory and instrumental behavior: Effects on licking and bar pressing in rats.

Maintained licking and bar pressing in 48 male hooded rats by intermittent water reinforcement. Shock punishment was delivered for either a reinforced or nonreinforced lick or bar-press response. Punishment suppressed licking more than bar pressing. Pairing punishment with reinforcement had little effect on overall response suppression. In Exp. II with 18 Ss, Ss punished for the 1st lick after a reinforced bar press showed more response suppression than Ss punished for the reinforced bar press. Results support R. Solomon's (see record 1965-00694-001) hypothesis than consummatory behavior is more sensitive to punishment than instrumental behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of cholecystokinin on taste preference and sensitivity in rats.

Determined, in 3 experiments with 10 Long-Evans rats, that cholecystokinin octapeptide (CCK-8) reduced the amount consumed or the number of licks of several concentrations of sucrose in short-term tests with Ss that were hungry, satiated, or fed ad lib. The suppressive effect of CCK-8 was generally smaller in the hungry than in the satiated or ad-lib condition. In the satiated and ad-lib conditions, there was no effect of sucrose concentration on the magnitude of the CCK-8 effect. In hungry Ss, the concentration-intake function for sucrose was lowered and flattened by both CCK and natural satiety. To determine whether a taste change is involved in this short-term reduction of sucrose intake, integrated chorda tympani responses were measured before and after iv infusions of CCK-8 or NaCl. The peak response to .3 M sucrose significantly increased after 2 5-μg infusions of CCK-8. Peak and tonic responses to sucrose and saline tended to increase after CCK-8 but not NaCl infusions. Results suggest that CCK-8 reduces sucrose intake in situations in which postingestional factors are minimal and that sucrose concentration has little effect on the size of this suppression. A change in perceived taste intensity or quality may play a role in the inhibitory effect of CCK-8 on intake. (33 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of lead exposure on licking and yawning behaviour in rats

Most studies on facial trauma in the pediatric age group focus on special subgroups. This investigation encompasses all traumatic facial injuries, minor and major, of children and adolescents. Epidemiological data of the type and pattern of injury of trauma patients less than 19 years of age, treated during a 3-year-period in a large metropolitan trauma centre were reevaluated. Of the 1385 patients, 68% had soft tissue injuries, 24% had dental trauma, and 8% fractures of facial bones. More than 90% suffered from minimal or minor trauma. The leading cause of injury was a fall, predominantly at the toddler stage. In adolescents an adult mechanism of trauma prevailed: over 60% of injuries were sequelae of an assault or altercation. The male sex predominated through all age groups and for all types of injuries. The bulk of soft tissue injuries are located within a small falling zone, extending from the nose to the mental area. There was a rising incidence of fractures of facial bones towards older age groups, mandibular fractures being the most common. Condylar fractures, with their potential impact on further growth of the mandible, are seen frequently in children and adolescents, making up 80% of the fractures of the lower jaw.     

Effects of unilateral striatal dopamine depletion on tongue force and rhythm during licking in rats.

To quantitatively assess the orolingual dysfunctions produced by unilateral striatal dopamine depletions, rats first received 6-hydroxydopamine injections into the nigrostriatal bundle and were then trained to lap water from a force-sensing disk in 2-min sessions. Compared with controls and rats with moderate (75%) dopamine depletions showed decreases in number of licks, lick rhythm, and lick peak force. Rats with substantial lesions were also impaired in making initial, within-session adjustments in lick peak force but not in lick rhythm. The results confirm the presence of Parkinson-like deficits in tongue dynamics during consummatory licking behavior in rats. The methods used here should prove useful in providing quantitative measures of the efficacy of experimental therapies in this rodent model of Parkinson's disease. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dissociation of licking and volume intake controls in rats ingesting glucose and maltodextrin.

The volume of fluid that rats acquire with each lick was systematically varied across short-term tests with 12.5% glucose (Experiment 1) or 12.5% maltodextrin (Experiment 2). For glucose, rats increased the number of licks emitted as lick volume was reduced such that meal size remained remarkably stable across all (8, 4, and 2 μl) but the smallest (1 μl) lick volume conditions tested. Rats similarly compensated for lick volume reduction (8 to 4 μl) with maltodextrin by approximately doubling the number of licks emitted. Meal duration and a number of lick-microstructural parameters (initial ingestion rate, mean burst duration, terminal lick and ingestion rates and burst duration) were not correlated with the intake outcome insofar as they varied significantly across conditions over which intake remained stable. Thus, in response to lick volume manipulation, rats demonstrated an impressive degree of behavioral flexibility in what may be regarded as a defense of meal size. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cholecystokinin changes the duration but not the rate of licking in vagotomized rats.

Abdominal vagotomy markedly reduces or abolishes the inhibitory effect of cholecystokinin (CCK-8) on meal size. To investigate the rate and microstructure of licking underlying this phenomenon, licking was measured throughout a meal of milk in intact and vagotomized rats after intraperitoneal injections of isotonic saline or CCK-8. CCK-8 increased the slope of the decay of licking, decreased the efficiency of licking, and decreased the duration of licking in intact rats but had no effect on either the slope of the decay of licking or the efficiency of licking, but it increased the duration of licking in vagotomized rats. These results demonstrate that abdominal vagal nerves are necessary for CCK-8 to increase the rate of decay of licking, but nonvagal mechanisms mediate the effect of CCK-8 on duration of licking. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Tolerance to naloxone-induced suppression of intake: Learning and cross-tolerance to cholecystokinin in rats.

Experiments were conducted to evaluate the contribution of conditioning to tolerance to the meal-suppressive effect of naloxone (Nx) in rats. The results indicated (a) Nx suppresses consumption in a dose-dependent manner; (b) tolerance to this suppression of intake is "contingent" (the rat must eat in conjunction with drug administration for tolerance to develop); (c) tolerance is displayed only in the context of environmental cues previously associated with Nx; (d) Nx-tolerant rats overeat when presented with cues previously associated with the drug; (e) Nx-tolerant rats display cross-tolerance to cholecystokinin. The results are consistent with C. X. Poulos and H. Cappell's (1991) "homeostatic" theory of tolerance, as well as with the results of other experiments indicating that conditioning contributes to tolerance to many effects of various drugs. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Endogenous cholecystokinin reduces vocalization in isolated 10-day-old rats.

Devazepide, the cholecystokinin (CCK) receptor blocker, markedly and specifically affected the behavior of 10-day-old rats isolated from mother and siblings. Whereas intraoral infusions of milk or fat, which cause CCK release, calmed infants, that is, reduced levels of ultrasonic vocalization, devazepide fully blocked this reduction. Devazepide did not reduce the elevated pain limen caused by milk or fat infusions. These data parallel earlier findings obtained with administration of exogenous CCK and implicate endogenous CCK in the maintenance of infant steady state and calm. The possibility that CCK contributes to the normal development of mother–infant affectional systems is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of sensory restriction upon responses to cortical stimulation in rats.

Assigned 43 Long-Evans hooded rats to 7 groups receiving normal, visually restricted, or auditory restricted rearing experience. Ss were then implanted with bipolar pairs of electrodes in the auditory and visual projection areas. Electrical stimulation of the cortex was used as a discriminative stimulus for a lever-pressing response. The ease of using electrical stimulation of visual or auditory cortex as a discriminative stimulus was related to Ss' paranatal sensory experience. Deleterious effects were limited to the restricted cortical projection area, and there were suggestions of facilitated performance in response to stimulation of the nonrestricted cortical areas. These effects were absent when restriction was induced in adulthood. (28 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Learning and tolerance to the intake suppressive effect of cholecystokinin in rats.

Experiments were conducted to evaluate the contribution of conditioning to tolerance to the meal suppressive effect of cholecystokinin (CCK). The results indicate that (1) tolerance was contingent (the rat had to eat in conjunction with drug administration for tolerance to the meal suppressive effect to develop), (2) tolerance was displayed only in the context of environmental cues previously associated with CCK, (3) CCK-tolerant rats overate when presented with cues previously associated with the peptide, and (4) CCK tolerance displayed latent inhibition. The results are consistent with C. X. Poulos and H. Cappell's (1991) homeostatic theory of tolerance, as well as with the results of other experiments indicating that conditioning contributes to tolerance to many effects of a variety of drugs. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The role of cholecystokinin in conditional compensatory responding and morphine tolerance in rats.

As elaborated in the conditioning analysis of tolerance, cues present at the time of drug administration become associated with the drug effect. A particularly salient cue that may become associated with the drug effect is the pharmacological drug-onset cue inherent to drug administration. Drug-associated cues contribute to tolerance by eliciting a conditional compensatory response that attenuates the drug effect. For example, the early drug effect, having been paired with the subsequent larger drug effect, may elicit the release of antiopioid peptides that counter opioid effects. The role of a putative antiopioid peptide, cholecystokinin-8 (CCK), in the associative mechanisms of opiate tolerance was evaluated. The results of these experiments suggest that a CCK2 receptor antagonist attenuates both the expression of opiate tolerance and the conditional compensatory response hypothesized to mediate such tolerance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Inhibition of ingestive behavior following fourth ventricle bombesin injection in chronic decerebrate rats.

Tested the hypothesis that the effects of 4th ventricle bombesin (BN) injection on feeding require interaction with forebrain neural systems by measuring intraoral sucrose (0.1 M) in tube-fed control and tube-fed supracollicular decerebrate rats after 4th ventricle injections of 1, 5, 10, 20, and 50 ng BN. Fourth ventricle injections of all doses of BN reliably suppressed sucrose intake in both control and chronic decerebrate rats. These results indicate that caudal brain-stem afferent signals produced by 4th ventricle BN injections are integrated by the local neural circuitry of the caudal brain stem, independent of the forebrain systems, to modulate ingestive behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Simultaneous contrast: Evidence from licking microstructure and cross-solution comparisons.

The microstructure of rats' licking responses was analyzed to investigate both “classic” simultaneous contrast (e.g., Flaherty & Largen, 1975) and a novel discrete-trial contrast procedure where access to an 8% test solution of sucrose was preceded by a sample of either 2%, 8%, or 32% sucrose (Experiments 1 and 2, respectively). Consumption of a given concentration of sucrose was higher when consumed alongside a low rather than high concentration comparison solution (positive contrast) and consumption of a given concentration of sucrose was lower when consumed alongside a high rather than a low concentration comparison solution (negative contrast). Furthermore, positive contrast increased the size of lick clusters while negative contrast decreased the size of lick clusters. Lick cluster size has a positive monotonic relationship with the concentration of palatable solutions and so positive and negative contrasts produced changes in lick cluster size that were analogous to raising or lowering the concentration of the test solution respectively. Experiment 3 utilized the discrete-trial procedure and compared contrast between two solutions of the same type (sucrose-sucrose or maltodextrin-maltodextrin) or contrast across solutions (sucrose-maltodextrin or maltodextrin-sucrose). Contrast effects on consumption were present, but reduced in size, in the cross-solution conditions. Moreover, lick cluster sizes were not affected at all by cross-solution contrasts as they were by same-solution contrasts. These results are consistent with the idea that simultaneous contrast effects depend, at least partially, on sensory mechanisms. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Role of cholecystokinin in the motivational control of instrumental action in rats.

In 4 experiments, the role of cholecystokinin (CCK) in the motivational control of instrumental performance in rats was assessed. Following instrumental training with food rewards, injections of CCK (either 2 μg/kg or 4 μg/kg) had no effect on instrumental performance in extinction, even when the opportunity was given to learn about the incentive value of the food outcome under CCK. These results contrasted markedly with the effects of shifts in food deprivation. Rewarded instrumental performance was, however, reduced by both doses of CCK, suggesting that CCK may mediate deprivation-related shifts in incentive value. Tests of this hypothesis found that the alimentary CCK antagonist devazepide (MK329) attenuated the devaluation of a food outcome produced by exposure to the outcome in a nondeprived state. These data are interpreted as suggesting that CCK may act as a satiety-specific incentive signal. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Suppression of licking behavior in rats as a function of predictability of shock and probability of conditioned-stimulus-shock pairings.

In Exp I, the effects of various degrees of predictability of electric shock upon rats' licking behavior were studied using 45 male albino rats. The basal rate of licking became progressively lower as unpredictability of shock increased. It was also found that Ss could utilize "time" as a predictor of safety and danger. In Exp II, using 48 Ss, the relationship between conditioned emotional response (CER) and the probability of conditional stimulus (CS) being paired with shock was studied under the matched basal rate of licking by making all shocks predictable. The CER was an increasing function of the probability of CS-shock pairings. Results are discussed with reference to M. Seligman's (1969) safety-signal hypothesis and R. Rescorla's (1968) probabilistic theory. (19 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of pretraining compatible and incompatible responses on subsequent one-way and shuttle-avoidance performance in rats.

Conducted 6 experiments with male Holtzman rats. A single noncontingent footshock was found to facilitate subsequent one-way and shuttle avoidance if the CS in preshock and avoidance training was the same. If the to-be-established instrumental response was punished during preshock, or if Ss were required to run toward the CS paired with shock during pretraining, the facilitative effects of preshock were eliminated. Facilitation by a single preshock was not enhanced if shock was escapable, regardless of the CSs, task, or whether escape was immediate or delayed. If Ss received 10 one-way escape trials, the beneficial effects of preshock on one-way and shuttle avoidance were enhanced. In contrast, shuttle-escape training produced no such beneficial effects on avoidance performance. (19 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of desalivation on drinking and air licking induced by water deprivation and hypertonic saline injections.

Previous studies show that desalivate (DS) rats drink more water than controls when maintained on a diet of dry food, but drink less than controls after a period of water deprivation. In the present series of studies, a total of 14 male and 2 female naive hooded rats served as Ss. Results show that DSs ate less food than sham operates (SHs), indicating that DSs' body fluids probably do not become as hyperosmotic as those of the SHs. When Ss were maintained on a moist mash during water deprivation, subsequent water intake and air licking were about the same for DSs and SHs. After combined food and water deprivation, both groups air-licked at greatly reduced rates. After subcutaneous injections of hypertonic saline, DSs air-licked just as much as SHs. It is concluded that DSs drink less after water deprivation because they eat less dry food than SHs during deprivation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of acute and chronic nicotine on responses maintained by primary and conditioned reinforcers in rats.

There is growing recognition that nonnicotine factors, such as the sensory stimuli associated with smoking, can play a critical role in the maintenance of cigarette smoking. However, little is known about the effects of nicotine on responding maintained by these stimuli, which are assumed to be conditioned reinforcers. The authors used an animal model to examine the acute and chronic effects of nicotine on responses maintained by food and conditioned reinforcers (i.e., lights) and responses in the absence of programmed consequences (i.e., extinction). During the acute phase, 4 male rats received 5 doses of subcutaneous nicotine. One dose of nicotine was then administered for a minimum of 60 days. Food-maintained and extinction responses did not significantly increase during the acute phase; however, food-maintained responses did increase during the chronic phase. Relative to vehicle, intermediate doses increased responses maintained by conditioned reinforcers during both phases. The results suggest that nicotine enhances responding maintained by conditioned reinforcers and possibly by food. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Combined, but not single, gustatory nerve transection substantially alters taste-guided licking behavior to quinine in rats.

On the basis of electrophysiological studies, the glossopharyngeal nerve (GL) is far more responsive to quinine than the chorda tympani (CTP) or greater superficial petrosal (GSP) nerves. The licking behavior of 72 male, water-deprived rats to quinine (0.03–3.0 mM) and distilled water (10-sec trials) was tested before and after various nerve transections. GL?+?CTP section caused a substantial reduction in responsiveness. GSP?+?CTP section had a moderate effect, and GL section alone produced only marginal impairments. Control, partially desalivated, and CTP-sectioned rats were unaffected. Thus, the GL is not necessary for normal unconditioned taste-guided appetitive responsiveness to quinine, but the collective input from the GSP and CTP is necessary and most likely sufficient. These data suggest that the quinine-evoked input of the GL and CTP converge centrally. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Odor preference and urine-marking scales in male and female rats: Effects of gonadectomy and sexual experience on responses to conspecific odors.

Investigation and urine-marking responses of 112 male and female Long-Evans rats toward conspecific urine odors were recorded in pair-wise comparison tests. Each of 16 S groups was given 15 preference tests, 1 for each of the possible pairs of 5 urine odors and a no-odor control (N). The urine sources were own group (G), intact male (M), castrated male (Mc), ovariectomized female (Fo), and estrous females (F). Results were scaled by using a technique based on L. L. Thurstone's (1927) law of comparative judgment. Intact males with sexual experience ordered their odor preferences N?