Consummatory Responses Research Articles

Facial consummatory responses in rats support the ponderostat hypothesis

Facial consummatory responses reflecting ingestive and aversive perceptions were studied and quantified in rats chronically implanted with gastric and oral catheters. A gustatory stimulus of 50 μl of 1.75 mol·1 −1 sucrose was injected into the mouth every 5 min during 60 min. At time zero, 1.7 ml of 3.3 mol·1 −1 glucose was injected into the stomach. Typical ingestive facial consummatory responses were observed in response to sweet stimuli prior to the gastric load. Aversive consummatory responses were observed in response to sweet stimuli after the glucose gastric load (negative alliesthesia). The rats were then fasted until they had lost about 14% of their body weight (from 411±34 g to 353±28 g). When lean, the rats were subjected to the same gustatory session as in the control period described above. In lean rats the gastric load of glucose was not followed by negative alliesthesia in response to sweet oral stimuli. In the last part of the experiment the rats were fed ad lib and they recovered their initial body weight. When the rats were subjected again to the same gustatory sessions, the gastric load was followed by negative alliesthesia in response to sweet stimuli. Thus, after recovering their initial body weight, the rats displayed the same response as in the control sessions prior to losing weight. These results in rats parallel results obtained in human subjects, and reinforce the hypothesis of the existence of a ponderostat regulating body mass.

Studies of Behavioral State in Aplysia.

This paper reviews a series of studies on the neural organization and the cellular mechanisms underlying behavioral states; in these studies, feeding behavior in Aplysia was used as a model system. Feeding in Aplysia has similarities to motivated behaviors in other animals and is modulated by a number of interesting state variables, including arousal. Food-induced arousal manifests itself in two categories of feeding behavior: (1) appetitive responses (e.g., head-up feeding posture and directed head turning), which orient the animal to potential goal objects such as food; and (2) consummatory responses (biting, swallowing), which obtain the goal object. The consummatory responses are rhythmic and relatively stereotyped, whereas the appetitive responses are highly variable. Our evidence suggests that one consummatory response, biting, appears to be controlled by command elements in the cerebral-ganglion, such as neuron CBI-2, which are capable of driving the behavior. One component of the appetitive behavior, head lifting, may be controlled (at least in part) by another cerebral neuron, C-PR. C-PR, however, affects numerous systems in the animal, but all the systems affected seem to be involved in the food-induced arousal state of the animal. We postulate that C-PR is, in some ways, analogous to command neurons that evoke behaviors. The C-PR, however, not only evokes a behavior, but also evokes a central motive state which aids in insuring that behavior is efficiently expressed.

Brain stimulation-induced feeding alters regional opioid receptor binding in the rat: an in vivo autoradiographic study

Although opioid antagonists block feeding behavior in a variety of animal models, the number and identify of CNS regions in which the inferred endogenous opioid activity mediates feeding have yet to be established. Furthermore, it is not yet clear whether the opioid activity that sustains feeding is a concomitant of the appetitive motivational state or the consummatory response. In an effort to address these issues, an in vivo autoradiographic method was used to visualize CNS regional changes in opioid release during appetitively motivating electrical stimulation in the lateral hypothalamus (ESLH) and during consummatory behavior elicited by such stimulation. Regional decreases in [ 3H]diprenorphine ([ 3H]Dpr) binding, suggesting increased release of an endogenous opioid peptide, were observed in the medial prefrontal cortex, medial septum, gustatory cortex, zona incerta, mediodorsal thalamus, and hippocampus of rats receiving ESLH. Decreased binding in the latter 4 structures did not appear when animals were allowed to eat during ESLH, suggesting that the inferred opioid release is associated with appetitive behaviors elicited by ESLH which are suppressed when food is available and consummatory behavior predominates. When animals were allowed to eat during ESLH, [ 3H]Dpr binding in anterior cingulate cortex decreased substantially, suggesting that feeding behavior specifically triggers opioid release in this region. ESLH and feeding were found to increase [ 3H]Dpr binding in a number of CNS regions. Alternative explanations for increased binding, including inhibition of tonic opioid release, changes in cerebral blood flow, and opioid receptor up-regulation are discussed.

Postingestive alliesthesia: The rat tells the same story

Facial consummatory responses reflecting ingestive and aversive perceptions were studied and quantified in rats chronically implanted with gastric and oral catheters. A gustatory stimulus of 50 μl of 0.6 mol·l −1 sucrose was injected into the mouth every 5 min during 60 min. At time zero, 5 ml of either 1.1 mol·l −1 glucose or water were injected into the stomach. The typical ingestive facial consummatory responses were observed in response to sweet stimuli prior to all gastric loads, and after the water loads. On the other hand, the aversive consummatory responses were observed in response to sweet stimuli after glucose gastric loads. The reversal of the consummatory responses from ingestive to aversive was stronger with higher concentration of the gastric load, and relatively independent from the volume of the load or the amount of glucose injected intragastrically. These results in rats parallel human postingestive alliesthesia.

The effect of unilateral anteromedial cortex lesions on prey-catching and spatio-motor behaviour in the rat

The neglect which follows a unilateral lesion of anteromedial cortex in rat was examined using two tasks. In the first task animals had to press the left bar of a two-bar Skinner box for food reward. In the second task animals captured live locusts presented in either their right or left visual field. The results showed that in the Skinner box there was a transitory spatial neglect contralateral to the lesion, which disappeared after 2–3 days. In the prey-catching task animals failed to target or track locusts when they were in the field contralateral to the lesion throughout the 4-day testing period. Capture and consummatory responses were normal when the locust was presented (or moved independently) into the ipsilateral (non-neglected) field. 60 days later the asymmetrical response to locusts in the contralateral field had disappeared.

HUMANS' SENSITIVITY TO VARIATION IN REINFORCER AMOUNT: EFFECTS OF THE METHOD OF REINFORCER DELIVERY

Two experiments examined human subjects' sensitivity to variation in reinforcer amount under different methods of reinforcer delivery. Subjects chose between schedules varying in terms of amount and/or delay of reinforcement, the reinforcer being points exchangeable for money. In Experiment 1, reinforcer amount was manipulated by varying the monetary value of the points across conditions while the number of seconds of access to a consummatory response remained constant. Choice was strongly sensitive to reinforcer amount and indicative of self-control, as in previous experiments. In Experiment 2, reinforcer amount was manipulated by automatically delivering different numbers of points during the amount period, and the consummatory response was eliminated. Sensitivity to variation in reinforcer amount was significantly lower than in Experiment 1. Furthermore, the subjects in Experiment 2 exhibited significantly less self-control than did the subjects in Experiment 1. Humans' sensitivity to variation in reinforcer amount appears to be affected by factors that enhance the discrimi-nability of the consequences of responding.

Linguistic analogies and behavior: The finite-state behavioral grammar of food-hoarding in hamsters

Rodger and Rosebrugh (1979) developed a method for identifying sets of rules by which discrete responses are combined to form functional sequences of behavior. In the present study, this so-called finite-state behavioral grammar method was used to analyze the food-hoarding behavior of Syrian golden hamsters ( Mesocricetus auratus). Specifically, it was used to analyze 127 videotaped food-hoarding sequences that were observed in 14 male, adult hamsters in an apparatus that comprised a home compartment, a foraging area, and a connecting tunnel. An integral part of grammar derivation is the development of hypotheses about the function of the observed response patterns to guide the grammar derivation. Two such hypotheses guided the present analysis: first, we hypothesized that behaviors observed in the foraging area after the hamsters' cheek pouches were filled served an exploratory function; second, we hypothesized that behaviors observed in the home compartment prior to the hamsters emptying their cheeck pouches served to assess potential food deposition sites. In addition to generating these two hypotheses and the grammars for the hoarding sequences, this study demonstrates how the finite-state grammar method can be used as a productive means of gaining insights into the organization of consummatory response sequences.

Effects of the imidazobenzodiazepine Ro 15-4513 on saccharin choice and acceptance, and on food intake, in the rat

The general aim of the present series of experiments was to investigate the effects of the imidazobenzodiazepine, Ro 15-4513, on ingestional behavior in the rat. The more specific aims were to test its effects on preference for sweet taste, to determine if it acts as a benzodiazepine-receptor inverse agonist, and if it selectively reduces sweetness preference. The results indicated that Ro 15-4513 (1.0–10 mg/kg, i.p.) abolished the preference for a 0.05% sodium saccharin solution in a two-choice test. Water intake in the same test was unaffected. Second, at 10 mg/kg, it suppressed saccharin in an acceptance test; this effect was completely reversed by the selective benzodiazepine antagonist, Ro 15-1788 (20 mg/kg). Third, Ro 15-4513 (1.0–10 mg/kg) reduced palatable food consumption in non-deprived rats, an effect which was also antagonized by Ro 15-1788. The results are consistent the bidirectional modulation of ingestional responses to palatable taste stimuli as a consequence of drug actions at benzodiazepine receptors. Furthermore, they emphasize that any reduction in consummatory responses produced by Ro 15-4513 is likely to reflect inverse agonist characteristics, as distinct from any putative ethanol antagonist property.

The role of a modulatory neuron in feeding and satiation in Aplysia: effects of lesioning of the serotonergic metacerebral cells

Food-induced arousal in Aplysia is characterized by a progressive increase in the speed and strength of biting responses elicited by a seaweed stimulus. Data from semi-intact and dissected preparations suggest that the identified, serotonergic, metacerebral cells (MCCs) of the cerebral ganglion contribute to food-induced arousal by enhancing the strength of buccal muscle contractions, and by modulating the output of the central pattern generator for biting movements. In order to test this hypothesis in intact, free-moving animals and to determine if the MCCs play a role in satiation of feeding, the behavior of animals that had their MCCs destroyed by intracellular injection of proteases was compared with that of B Cell-Lesion and Dye injection control animals (Experiment 1) or surgical control animals (Experiment 2). Nonfeeding behaviors such as defensive withdrawal responses, locomotion, and righting reflexes were unaffected by MCC lesioning. Also unaffected by MCC lesioning were appetitive feeding behaviors and the amount of food needed to satiate animals. Significant behavioral deficits in consummatory feeding behaviors, which remained stable for periods exceeding 10 d, were observed in the MCC-lesioned animals but not in controls. Lesioned animals exhibited a slowing of rate of repetitive biting responses by 40% of controls and had reduced magnitudes of repetitive bites, particularly at the end of a testing run of 10 consecutive bites. The deficit in bite magnitude was minimally evident in food-deprived animals (Experiment 1) but became more pronounced as animals were fed to satiation (Experiment 2). MCC-lesioned animals still exhibited a residual build-up of the rate and magnitude of biting responses at the onset of feeding behavior. This suggests that, in addition to the MCCs, there are other sources of modulation that contribute to plasticity of consummatory responses during the food-induced arousal state.

Dopamine and preparatory behavior: III. Effects of metoclopramide and thioridazine.

The effects of metoclopramide and thioridazine on feeding behaviors of male hooded rats were investigated in 2 experiments. Metoclopramide (2.5-7.5 mg/kg) attenuated conditioned preparatory responses to a conditional stimulus signaling delivery of a meal. However, consummatory responses were affected only by the highest dose. Similar effects had previously been observed following administration of pimozide (Blackburn, Phillips, & Fibiger, 1987). Thioridazine (10-30 mg/kg) had no significant effect on any measure of feeding behavior. The different effects of the 2 drugs may be related to their preferential actions at dopamine terminals in anatomically distinct regions of the forebrain.

Antagonism of selected ethanol-enhanced brain stimulation properties by Ro 15-4513

Low doses of ethanol increase responding for brain stimulation. Recently, other intoxicating effects of ethanol have been reversed by the imidazobenzodiazepine, Ro 15-4513. Possibly, Ro 15-4513 blockade also acts on reward-enhancing properties of ethanol. Rats trained to alternately shuttle between nose poke and lever operanda for rewarding stimulation to the medial forebrain bundle, were tested following intragastric intubations of ethanol (18%, 1.35 g/kg), Ro 15-4513 (3 mg/kg in 18% ethanol), or vehicle. Ro 15-4513 reversed ethanol-enhanced effects on reinforced responses. Because Ro 15-4513 did not completely block instrumental responding for brain stimulation, we conclude its effects on ethanol were not acting on the same reward substrate as the current and consummatory response.

Dopamine and preparatory behavior: II. A neurochemical analysis.

Changes in the activity of dopamine-containing systems in relation to preparatory and consummatory feeding responses were investigated. In Experiment 1 rats were conditioned to associate food delivery with the presentation of a conditional stimulus (CS+). When sacrificed after exposure to the CS+ alone on a test trial, the ratio of the dopamine metabolite 3,4-dihydroxyphenylacetic acid to dopamine (DOPAC/DA ratio) was increased significantly in the nucleus accumbens. A similar trend in the ratio of homovanillic acid to dopamine (HVA/DA ratio) was also observed. Similar increases were observed in the striatum, but these were not statistically significant. In contrast, no increases were observed in the DOPAC/DA ratio or the HVA/DA ratio in either brain region when rats were permitted to consume an unsignaled meal for 7 min. These findings suggest that activation of dopamine terminals in the nucleus accumbens occurs during the anticipation of a meal, at which times the rat is engaged in preparatory feeding behaviors, but does not accompany the performance of short bouts of consummatory feeding behavior.

Differences in cyclophosphamide-induced suppression of cricket predation in selectively bred strains of taste-aversion prone and resistant rats.

Cyclophosphamide-induced conditioned suppression of cricket predation was observed in taste-aversion-prone (TAP) but not in taste-aversion-resistant (TAR) rats. These TAP and TAR strains had been selectively bred for efficient or inefficient acquisition of cyclophosphamide-induced saccharin taste aversions (TAs). Equivalent preconditioning cricket predation was practiced by nonfasted subjects of both strains. TAR rats that ate crickets before a cyclophosphamide injection were thereafter voracious predators as were saline-injected and pseudoconditioning controls of both strains. However, conditioned TAP rats subsequently displayed a marked suppression of cricket predation. Predation can provide a deprivation-free and species-natural consummatory response for studies of strain differences in TA conditionability of TAP and TAR rats. In addition, the present results indicate that TAP and TAR strain differences in TA conditionability are not restricted to the saccharin solution that was the conditioned stimulus basis of prior strain development.

Hyperresponsiveness to stress: differential effects of prenatal ethanol on males and females.

In this study we investigated the hypothesis that pituitary-adrenal response inhibition is compromised in animals prenatally exposed to ethanol. In the first experiment, we examined whether opportunity to perform a consummatory response reduces the adrenocortical response to a novel test cage. Animals were water deprived for 24 hr and tested in one of three conditions: (a) removed from home cage, blood sample obtained immediately; (b) placed into empty novel cage, blood sample obtained 30 min later; (c) placed into novel cage with water available, blood sample obtained 30 min later. All animals showed an increase in corticoids over basal levels following 24-hr water deprivation, and placement into a novel cage produced a further significant increase in corticosterone. Opportunity to drink reduced the corticosterone response to novelty for all males. However, fetal ethanol-exposed females showed significantly less attenuation of their corticosterone response to novelty than both pair-fed and control females. In the second experiment, we examined adrenocortical habituation to a stressful stimulus. Animals were restrained in plastic tubes which restricted movement, and blood samples were obtained following 30 or 60 min of restraint. All animals showed significant corticoid elevations at 30 min. Males showed no change in corticoids from 30 to 60 min while both pair-fed and control females showed a corticoid decrease at 60 min. Fetal ethanol-exposed females, however, showed no significant corticoid decrease at 60 min.(ABSTRACT TRUNCATED AT 250 WORDS)

Operant response requirements affect touching of visual reinforcement by infants

Studies of instrumental learning in infants have been concerned with negative transfer between noncontingent and contingent learning experiences, sparking debate about the value of responsive environments and calling for measures beyond operant performance to shed light on the underlying perception of contingency. The present studies focused on contingent versus non-contingent stimulation and their effect on attention and consummatory responses as unlearned features of the infant’s interaction with stimuli. In each experiment the dependent variable was tactile behavior directed toward pictures, and the independent variable was the type of contingency controlling the pictures. In Experiment 1, 12- to 18- month-old infants were tested in the laboratory using a modified discrete-trial operant procedure in which a touch-sensitive video screen served as both a projection surface and a touch-recording device. Infants touched contingent slides significantly more often than noncontingent slides. Experiment 2 extended this effect to fixed-ratio 1 (FR-1) versus fixed-ratio 2 (FR-2) schedules of reinforcement. A second group of 12- to 18-month-old infants showed a similar pattern; they touched the FR-2 slides significantly more often than the FR-1 slides. These findings indicate that factors other than operant behavior vary as a function of the degree of contingency in an instrumental situation, and hint at possible cognitive processes that compare contingency “rules” governing the responsiveness of a changing environment.

Combining sensory reinforcement and texture fading procedures to overcome chronic food refusal

Previous research has demonstrated behavioral programs to be effective in treating children with selective food preferences. However, there are few examples of interventions for the child displaying almost total food refusal. The present program combined sensory reinforcement and texture fading procedures to treat a 4-year-old deaf, visually impaired child who only consumed milk and, occasionally, pureed baby food. Sensory reinforcement consisted of the contingent presentation of light and rocking motion following consummatory responses. Texture fading entailed gradually increasing food composition. Results indicated that treatment was associated with substantial increases in the consumption of solid foods. Effects were maintained following the withdrawal of sensory reinforcement and with meals presented outside of the original treatment settings. Various features of the program are highlighted and discussed.

Hedonic response of rats to polysaccharide and sugar solutions

The palatability of glucose, sucrose, maltose and polysaccharide (Polycose) was assessed by examining the consummatory response of nondeprived female rats to equicaloric or equimolar solutions of these saccharides. Both 30-min one-bottle acceptance and 30-min two-bottle preference tests were conducted: initial (3-min) lick rates were also recorded. At low molar concentrations the relative palatability of the saccharides was ordered as follows: Polycose greater than maltose greater than sucrose greater than glucose. At higher concentrations the rats were more attracted to sucrose than to Polycose; however Polycose remained more palatable than maltose at all but the highest concentration. In the one-bottle tests gram solute intakes varied as a function of percentage concentration, and was not influenced by saccharide type or solution osmolarity. The results along with other recent findings indicate that rats can taste starch-derived polysaccharides and find them quite palatable.

Relationship of type A behavior pattern in smokers to carbon monoxide exposure and smoking topography.

Stress-related physiological factors have been proposed to mediate the Type A behavior pattern (TABP) and coronary heart disease (CHD). However, collateral behavioral factors, such as the exaggerated consummatory response patterns of Type As, may also be involved. Study 1 examined this hypothesis by comparing exposure to cigarette smoke in 42 graduate and undergraduate student smokers assessed for the TABP. After controlling for smoking rate and Federal Trade Commission cigarette carbon monoxide yield, Type As' alveolar carbon monoxide (COa) levels were higher than Type Bs', and Jenkins Activity Survey scores were correlated with COa. To determine the source of this difference, we measured smoking topography in 10 Type As and 10 Type Bs in Study 2. Type As and Type Bs did not differ in number of puffs taken or puff volume, but Type As' inhalation duration was 70% longer than Type Bs'. These results suggest that consummatory behaviors of Type As may help account for the Type A-CHD relationship for smokers. Due to increased smoke exposure, Type A smokers may also be at greater risk for cancer and lung disease than Type B smokers.

Reinforcement delay of one second severely impairs acquisition of brain self-stimulation

The effect of delayed reinforcement on the acquisition of lateral hypothalamic self-stimulation was investigated. Brain stimulation reinforcement minimizes cues associated with reinforcement delivery (secondary reinforcement) and, by eliminating consummatory responses, permits precise temporal control of the interval between the operant response and reinforcement. Different groups were trained in daily 1-h sessions for brain stimulation reinforcement at one of 4 delay intervals (1, 2, 3 or 6 s). Responses made during the delay interval were not reinforced and reset the delay timer. Control groups (IMMEDIATE) were reinforced immediately, but were required to space responses--according to a delayed reinforcement of low rates (DRL) schedule--for an interval corresponding to one of the delay of reinforcement intervals. The DRL schedule equalized opportunities for reinforcement and non-reinforcement. At all intervals, rats trained with delayed reinforcement had significantly lower bar-press rates than controls trained with immediate reinforcement under DRL. When reinforcement schedules were switched (DELAY groups now get IMMEDIATE and vice versa), response rates rapidly shifted to levels appropriate to the new schedule. The pre-switch results indicate that delays even as short as 1 s markedly impede the acquisition of self-stimulation behavior. The post-switch results suggest that delay of reinforcement, like stimulation intensity, may determine the strength of hypothalamic reinforcement and hence final levels of performance.

Effects of acute food and/or water deprivation on muricide

The present experiment was designed to test certain predictions derived from models of interactions between muricide and appetitive behaviors proposed earlier by Russell and Singer [8,9]. One of the major features of the models centered on whether the two types of behavior are inevitably related. The general design of the present experiment involved testing for muricide either (a) after deprivation of food and/or water or (b) at times during the normal diurnal cycle when the two consummatory responses were at their minima and maxima. Deprivation and testing for muricide were limited to a single episode in order to eliminate confounding effects of repeated deprivations and of repeated exposures to prey. Periods of acute deprivation ranging from 5.5 to 22.0 hr did not induce significant quantitative changes in muricidal behavior. However, muricide and the appetitive behaviors did co-vary under conditions associated with the normal diurnal cycle. Comparing the present results with findings from experiments using repeated deprivation leads to the suggestion that covariation of appetitive and muricidal behaviors is not an innate characteristic, but rather is acquired through processes of learning. Present results further suggest that each of the two types of behavior has its own physiological substrate which can be modified independently, but also may be activated concomitantly by a common set of antecedent conditions.