Trigeminal orosensation and ingestive behavior in the rat.

Used a deafferentation procedure with male Wistar rats to examine the contributions of trigeminal orosensation to control of ingestive behavior. The procedure removed somatosensory input from the mouth while sparing olfaction, lingual taste, vibrissae inputs, and proprioceptive afferents from and efferents to the jaw muscles. Ss with sections of tongue or jaw muscle efferents served as controls. Bilateral trigeminal orosensory deafferentation was followed by effects on ingestive behavior, the magnitudes of which were proportional to the extent of the deafferentation. The trigeminal syndrome includes aphagia and adipsia, impairments in the sensorimotor control of eating and drinking, decreased responsiveness to food and water, and a reduction in the level of body weight regulation. Trigeminal deafferentation spared elementary ingestive movement patterns (biting, licking, and chewing) but disrupted their control by the perioral stimuli. Deficits in food intake varied with the sensory properties of the diet. Recovery of intake took place along a palatability gradient, and recovery of water intake paralleled that of dry food. The chronically reduced body weight was caused by persistent hypophagia and reflected reduced responsiveness to food. Findings suggest a considerable degree of overlap in the neural mechanisms mediating the sensorimotor and motivational control of intake in the rat. (76 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Trigeminal reflexes and ingestive behavior in the rat.

Used photographic, eletrophysiological, and neurobehavioral analyses in 3 experiments with 21 Wistar rats to examine the contribution of trigeminally mediated jaw-opening reflexes to the control of ingestive behavior. During eating and drinking, jaw opening was always preceded by a period of perioral contact with the food or water source (Exp I). Electrical and mechanical stimulation of perioral areas in Ss that were anesthetized with chlorprothixene (0.3 ml) and either ketamine HCl (0.05 ml/100 g) or chloralose (80 mg/kg) elicited jaw-opening reflexes (recorded from the mylohyoid nerve trunk) at short latencies and low stimulus intensities (Exp II). Trigeminal orosensory deafferentation (sparing jaw muscle afferents and efferents, taste, vision, and olfaction) abolished or significantly reduced mouth opening during eating or drinking (Exp III). It is concluded that motivational processes operate through trigeminal reflexes to generate eating in rats. (37 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Anticipatory cues can interfere with inhibitory operant behavior in the rat

In four separate experiments a total of 24 male rats were trained for 30 min. daily in the same temporal order to inhibit their responses for at least 6 sec. before a response-contingent reward was delivered (DRL-6 sec.). The rats tested as the second group each day displayed about twice the number of errors (effect size = 40%) shown by rats tested in the first or third groups. These results suggest that anticipatory cues, acquired within two sessions, interfere with response inhibition during an appetitive task for a limited time (between a few minutes to about one hour). The results are consistent with the hypothesis that learned anticipation of reward may decrease inhibitory mechanisms by facilitating limbic lability.     

Trigeminal deafferentation and ingestive behavior in rats.

For studying the role of orosensory input in the control of ingestive behavior, 46 male albino Wistar rats were subjected to varying degrees of trigeminal deafferentation in 2 experiments. Somatosensory branches that convey touch, temperature, and pain from the oral cavity were sectioned selectively, and muscles of mastication and taste afferents were left intact. Severe intake deficits were produced, including aphagia, adipsia, and prolonged hypophagia, accompanied by a corresponding decrease in body weight. The deficits were proportional to the extent of deafferentation and were most severe when upper and lower portions of the mouth were affected. Although somatosensory impairment affected the organization of the consummatory response, all Ss could bite, chew, and lick. Analysis of feeding patterns showed that minimally (mandibular) deafferented Ss compensated for the consummatory inefficiency by increasing meal duration but failed to initiate meals at the normal rate, thus keeping food intake below normal levels. Results suggest that oral somatosensory input is critical for the mechanisms that regulate ingestive behavior. (45 ref)) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Instrumentation for operant behavior research.

Reviews instrumental development in behavioral research from modular relay control equipment, and solid-state digital logic to the present-day digital computer. The major advantage in the digital computer is considered to be its "stored-program capability and the fact that the program is a set of logical commands," which can be altered during the course of the experiment by a simple device, i.e., a typewriter keyboard. The fixed ratio 7 (FR7) reinforcement schedule is presented as an example of the applicability of a digital computer in controlling behavioral experiments. The interface of the FR7 required for working wich a pigeon is built around the input-output structure of the LINC computer. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Septal influences on operant responding in the rat.

In 3 experiments with a total of 74 male albino Sprague-Dawley rats, the afferent and efferent connections of the septum with the hippocampus (fornix) or with the hypothalamus and lower brain stem (medial forebrain bundle) were transected by means of an encephalotome near the point where these pathways enter or leave the septal area. A transection of the fornix that produced minimal direct damage to cellular components of the septum or hippocampus reproduced the effects of large septal lesions on responding in several temporally defined paradigms that involve periods of response suppression (DRL, discriminated Sidman avoidance, FI). Transection of the medial forebrain bundle fibers that interconnect the septum with the hypothalamus and lower brain stem did not affect behavior in any of these paradigms. It is suggested that these observations be viewed in the context of the results of earlier investigations by the authors (see record 1974-27002-001), R. J. Carey (see record 1969-13784-001), and J. M. McDougall et al (see record 1969-13791-001), which showed that transection of the medial forebrain bundle reproduces several other components of the septal lesion syndrome. (28 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Some clinical correlates of operant behavior.

"22 chronic psychotic patients, Ss in an operant conditioning study, were given psychological tests and rated as to their ward behavior. Ratings of ward behavior and rates of operant response were directly related. Those patients who were testable by at least one clinical test were those who were high operant responders. These findings were discussed in terms of a notion of adaptability to the demands of the hospital environment. Clinical and operant data on 6 normal Ss were also presented." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Social facilitation of operant behavior in satiated rats.

Tested 24 male, Long-Evans hooded rats in 2 motivational states (hungry and satiated) and 2 social conditions (single and paired) in adjacent and communicating Skinner boxes for the effect of a social stimulus on operant behavior. The social stimulus interfered in all conditions except 1: satiated Ss paired with hungry Ss pressed the bar significantly more often than in any other condition. It is concluded that the social facilitation effect is produced by progressive changes in the motivational state of the S as well as by a set of stimuli triggering the operant behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The operant conditioning of human motor behavior.

"This paper reports procedures for the direct application of the variables defining the paradigm for operant conditioning to human behavior, and shows that human beings act very much indeed like experimental animals when they are subjected to the same experimental treatments. It suggests that direct application of conditioning principles to some categories of human behavior may be justified. The procedures are simple, and they may be followed by anyone, with a minimum of equipment." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A comparison of adult and adolescent rat behavior in operant learning, extinction, and behavioral inhibition paradigms.

Poor self-control, lack of inhibition, and impulsivity contribute to the propensity of adolescents to engage in risky or dangerous behaviors. Brain regions (e.g., prefrontal cortex) involved in impulse-control, reward-processing, and decision-making continue to develop during adolescence, raising the possibility that an immature brain contributes to dangerous behavior during adolescence. However, very few validated animal behavioral models are available for behavioral neuroscientists to explore the relationship between brain development and behavior. To that end, a valid model must be conducted in the relatively brief window of adolescence and not use manipulations that potentially compromise development. The present experiments used three operant arrangements to assess whether adolescent rats differ from adults in measures of learning, behavioral inhibition, and impulsivity, within the aforementioned time frame without substantial food restriction. In Experiment 1, separate squads of rats were trained to lever-press and then transitioned to two types of extinction. Relative to their baselines, adolescent rats responded more during extinction than adults, suggesting that they were less sensitive to the abolishment of the reinforcement contingency. Experiment 2 demonstrated similar age-related differences during exposure to a differential reinforcement of low rates schedule, a test of behavioral inhibition. Lastly, in Experiment 3, adolescent's responding decreased more slowly than adults during exposure to a resetting delay of reinforcement schedule, suggesting impaired self-control. Results from these experiments suggest that adolescents exhibit impaired learning, behavioral inhibition and self-control, and in concert with recent reports, provide researchers with three behavioral models to more fully explore neurobiology of risk-taking behavior in adolescence. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Consort bonding and operant behavior by female rhesus monkeys.

An operant conditioning situation was used to relate the leverpressing performance of female rhesus monkeys to different measures of social, sexual, and agonistic behavior that underlie the formation and dissolution of consort bonds. Nine females were trained to press a lever 250 times to gain access to a male partner. After access, a standard 60-min behavioral test took place (1,440 tests). Data were analyzed independently of the stage of the menstrual cycle. Eight females were tested with 2 males, and every female gained access faster with 1 male (i.e, preferred partner). For all 8 females, the preferred male was the one that spent more time grooming the female. For 5 females, the preferred partner was also the one that ejaculated more frequently. For 4 females, where agonistic interactions with males could be evaluated, the preferred male was the one that elicited fewer submissive behavioral patterns. These results indicate that the operant behavior of female rhesus monkeys is positively reinforced by social and sexual factors and negatively reinforced by agonistic interactions and may thus provide a measure of the strength of consort bonds. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Enduring problems for molecular accounts of operant behavior.

Although the Associative Learner (AL) theory advocated by C. P. Shimp et al (see record 1990-21730-001) can simulate several features of human and nonhuman performance in free-operant situations, it fails to account for many of the findings that are theoretically most powerful. It underestimates the sensitivity of behavior to relative reinforcement rate and totally omits any role for incentive variables such as amount and delay of reinforcement. At present, it is not sufficiently comprehensive to serve as an adequate alternative to R. J. Herrnstein's (see PA, Vol 44:10034; see also 1961) matching theory as a general account of behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Opioid-reinforced operant behavior: Selective suppression by alpha-methyl-para-tyrosine.

Conducted 4 experiments using a total of 24 Charles River male albino rats. Morphine-addicted Ss performed operant responses for opioid or milk rewards. When Ss were then denied access to opioids, abstinence symptoms developed. Responding under extinction conditions 2 wks after opioid withdrawal provided a measure of the "relapse" tendency. Systemic administration of alpha-methyl-para-tyrosine, an inhibitor of catecholamine synthesis, suppressed these responses if they had been reinforced by an opioid but not if they had been established with milk reinforcement. This indicates that the integrity of the catecholamine systems is vital for relapse to occur. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reversal of H-reflex operant conditioning in the rat

After developing a rapid gel filtration method to prepare pure and stable apoenzyme forms of D-amino acid oxidase from the yeast Rhodotorula gracilis, we carried out comparative kinetic studies on the reconstitution to holoenzyme (with FAD) of the intact (40 kDa) and proteolyzed (38.3 kDa) apoenzyme forms of this oxidase. Changes in catalytic activity and flavin and protein fluorescence revealed that in both cases reconstitution was biphasic. The proteolyzed enzyme was catalytically competent, but unlike the intact form was unable to dimerize following formation of the apoprotein-FAD complex. We present evidence that reconstitution of holoenzyme from apoenzyme plus FAD does not involve dimerization, and that dimerization is not necessary for expression of DAAO activity. We propose that both apoenzyme forms share a common reconstitution mechanism, which includes a step of conformational interconversion of an enzymatically active intermediate to the final holoenzyme.     

Acculturation and ethnic-minority health behavior: A test of the operant model.

Objective: The Operant Model of Acculturation predicts that health behaviors that have a low prevalence ( 45%) among Traditional minorities decrease with acculturation and thereby have a lower prevalence among their acculturated cohorts. The purpose of this study was to test this model for the first time. Design: Data on the 7,249 Mexican American adults in the 2001 California Health Interview Survey (CHIS), a statewide, random-digit-dial telephone survey, were used. Main Outcome Measures: Two proxies for acculturation (nativity, language spoken at home) were predictors in analyses of cigarette smoking, exercise, and 5 + daily fruit/vegetable consumption. Results: For all three health behaviors, results were fully supportive of the Operant Model irrespective of acculturation-proxy and demographic variables. Conclusion: The Operant Model may provide a coherent framework for predicting and understanding the role of acculturation in ethnic minority health behavior. Findings are discussed in terms of tailoring and targeting interventions in a manner consistent with the acculturation-related changes in health behavior that are likely to occur. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Gestational methylmercury exposure selectively increases the sensitivity of operant behavior to cocaine.

Developmental methylmercury (MeHg) exposure alters dopamine neurotransmitter systems, but the selectivity of this and the effects of low, environmentally relevant MeHg exposure regimens are poorly understood. In previous reports, some including littermates of animals studied here, chronic, low-level exposures affected performance on reversal tasks and enhanced reinforcer efficacy. Using high- and low-rate operant behavior under a fixed interval (FI) schedule, sensitivity was examined to drugs that target noradrenergic and dopaminergic neurotransmitter systems. Female rats were exposed in utero to 0, 0.5, or 5 ppm of mercury, as MeHg, via maternal drinking water. Selenium (Se) is thought to attenuate MeHg's neurotoxicity, so animals consumed a diet containing 0.06 or 0.6 ppm of Se. At 11 months, they lever-pressed under a FI 120” schedule of sucrose reinforcement. Acute dose-effect curves were generated with cocaine, desipramine, SKF-38393, quinpirole, SCH-23390, and sulpiride. As compared with unexposed animals, those exposed to 5 ppm mercury, regardless of Se exposure, were 2 to 3 times more sensitive to the rate-reducing effects of high doses of cocaine and did not show increased responding earlier in the interval following moderate cocaine doses. Cocaine's effects in the 0.5 ppm Hg groups depended on dietary Se: low Se diet resulted in a rightward shift in the DEC compared to controls, whereas a high Se diet did not. No differential effects of MeHg were seen with the other drugs. Gestational MeHg exposure produces irreversible sensitivity to dopamine, but not norepinephrine, reuptake inhibitors and not to drugs that target D1 or D2 receptors. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Menstrual cycle influences on operant behavior of female rhesus monkeys.

Nine female rhesus monkeys were paired with males throughout 63 menstrual cycles. The females' motivation to approach males was studied with an operant conditioning paradigm that required the female to press a lever 250 times to gain access to the male. Sexual behavior was scored during standard 60-min tests that followed the attainment of access (17 pairs; 1,440 tests). In the overall data, mean times to access were shortest at mid-cycle and longest just before and after the onset of menstruation, and a model-fitting method showed that 45% of cycles from individual pairs were significantly correlated with a V-shaped model of the overall pattern. Male sexual activity was highest at mid-cycle and lowest in the last quarter of the cycle, but the changes in access times could not be attributed entirely to the rewarding effects of the ejaculations. In the combined data from 5 females (9 pairs; 33 cycles), high estradiol levels and low progesterone levels were statistically associated with short access times and short ejaculation times. The overall effect was for operant performance and sexual activity to be synchronized and maximized in the periovulatory period of the menstrual cycle. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Neocortex and feeding behavior in the rat.

Consummatory behavior and weight-regulation capacity were measured in 12 normal male Long-Evans rats and in 43 similar Ss that survived complete (C), sequential unilateral (U), anterolateral (A) , or posterior (P) neocortical ablations. Groups C and A displayed aphagia and adipsia followed by a sequence of recovery stages qualitatively identical to, but shorter than, recovery typically seen following lateral hypothalamic lesions. After recovery, Group C displayed long-term effects of finickiness and prandial drinking. These effects and a measure of recovery of body-weight-regulation capacity were significantly intercorrelated with lesion size, and body-weight set point remained significantly lower than normal. Group U was relatively unaffected by the 1st unilateral ablation and showed, relative to Group C, facilitated recovery of consummatory behaviors following the 2nd ablation, but displayed the long-term effects. Group P, though significantly affected by the lesion, did not display the pattern or intensity of effects described for the other bilaterally ablated groups. (47 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Gustation and ingestive behavior in the rat.

Studied the contribution of taste to the quantitative control of intake and body weight in 15 male Wistar rats. Gustatory deafferentation was produced by combined bilateral section of the chorda tympani and glossopharyngeal nerves and the pharyngeal branch of the vagus nerve. The procedure did not affect the condition of the mouth, impair orientation to sensory stimuli, or severely disrupt the consummatory sequence. Nevertheless, deafferented Ss showed reduced responsiveness to food and water, elevated quinine HCl aversion thresholds, and impaired feeding efficiency. Food and water intake and body weight remained below control levels for at least 40–50 days postoperatively. Food intake deficits were not observed when Ss were offered ad lib pablum, a result suggesting that increased palatability could compensate for decreased gustatory input. The order of recovery of food intake through different diet types suggests a heightened responsiveness to taste stimuli. The effects of gustatory deafferentation are compared with those seen after section of trigeminal orosensory nerves, and the differential contributions of oral taste and oral touch are discussed. (42 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sampling behavior in the radial maze and operant chamber: Role of the hippocampus and prefrontal area.

Rats were observed in the radial maze and in an operant setting where errors were, within limits, impossible to commit. Under these circumstances, the Ss were free to seek information from the environment by varying their behavior, if they chose to do so, without penalty of nonreward. Rats with hippocampal, but not prefrontal or parietal damage, sampled fewer successive arm choices in the maze and exhibited a greatly reduced sensory analysis of the maze and its context. In operant chambers equipped with multiple levers, only hippocampal lesions narrowed the variety of interresponse intervals, which resulted in rhythmic responding. In contrast, the distribution of responses across the 3 response targets was not influenced by central nervous system injury. This pattern of information deprivation imposed by the hippocampal lesion parallels the profile of performance of such animals on more conventional tasks that depend on such information for optimal performance. The sampling deficits were not direct outcomes of the hippocampal damage. Close scrutiny revealed that the rigidity developed over time, albeit quite rapidly. Thus the narrowed behavioral variation following hippocampectomy depends on some interactive component of task experience. It is argued that reward is the other critical ingredient. (PsycINFO Database Record (c) 2010 APA, all rights reserved)