Cocaine-induced brainstem seizures and behavior

A variety of abnormal sensory/motor behaviors associated with electrical discharges recorded from the bilateral brainstem were induced in adult WKY rats by mechanical (electrode implants) and DC electrical current stimulations and by acute and chronic administration of cocaine. The electrode implant implicated one side or the other of the reticular system of the brainstem but subjects were not incapacitated by the stimulations. Cocaine (40 mg/kg) was injected subcutaneously for an acute experiment and subsequent 20 mg/kg doses twice daily for 3 days in a chronic study. Cocaine generated more abnormal behaviors in the brainstem perturbation group, especially the electrically perturbated subjects. The abnormal behaviors were yawning, retrocollis, hyperactivity, hypersensitivity, “beating drum” behavior, squealing, head bobbing, circling, sniffing, abnormal posturing, and facial twitching. Shifts in the power frequency spectra of the discharge patterns were noted between quiet and pacing behavioral states. Hypersensitivity to various auditory, tactile, and visual stimulation was present and shifts in the brainstem ambient power spectral frequency occurred in response to tactile stimulation. These findings suggest that the brainstem generates and propagates pathological discharges that can be elicited by mechanical and DC electrical perturbation. Cocaine was found to activate the discharge system and thus induce abnormal behaviors that are generated at the discharge site and at distant sites to which the discharge propagates. Cognitive functions may also be involved since dopaminergic and serotonergic cellular elements at the brainstem level are also implicated.     

Cocaine-induced brainstem seizures and behavior.

A variety of abnormal sensory/motor behaviors associated with electrical discharges recorded from the bilateral brainstem were induced in adult WKY rats by mechanical (electrode implants) and DC electrical current stimulations and by acute and chronic administration of cocaine. The electrode implant implicated one side or the other of the reticular system of the brainstem but subjects were not incapacitated by the stimulations. Cocaine (40 mg/kg) was injected subcutaneously for an acute experiment and subsequent 20 mg/kg doses twice daily for 3 days in a chronic study. Cocaine generated more abnormal behaviors in the brainstem perturbation group, especially the electrically perturbated subjects. The abnormal behaviors were yawning, retrocollis, hyperactivity, hypersensitivity, "beating drum" behavior, squealing, head bobbing, circling, sniffing, abnormal posturing, and facial twitching. Shifts in the power frequency spectra of the discharge patterns were noted between quiet and pacing behavioral states. Hypersensitivity to various auditory, tactile, and visual stimulation was present and shifts in the brainstem ambient power spectral frequency occurred in response to tactile stimulation. These findings suggest that the brainstem generates and propagates pathological discharges that can be elicited by mechanical and DC electrical perturbation. Cocaine was found to activate the discharge system and thus induce abnormal behaviors that are generated at the discharge site and at distant sites to which the discharge propagates. Cognitive functions may also be involved since dopaminergic and serotonergic cellular elements at the brainstem level are also implicated.     

Magnitude and duration of the effects of cocaine on conditioned and adjunctive behaviors in the chimpanzee.

Characteristic patterns of conditioned key-pressing were maintained in the chimpanzee under a multiple 30-response fixed-ratio, 10-minute fixed-interval schedule of food presentation. Adjunctive drinking occurred with regularity during the fixed-interval schedule and, with less frequency, during 1-minute timeout periods that followed each food presentation; drinking seldom occurred during the fixed-ratio schedule. Cocaine increased key pressing under the fixed-interval schedule at doses between .1 and 3.0 mg/kg, but adjunctive drinking and key pressing under the fixed-ratio schedule did not increase at any dose. Conditioned and adjunctive behaviors were disrupted and suppressed for different durations at 10,0 mg/kg, a dose which induced convulsive seizures within 10 minutes after intramuscular injection. A time-course analysis showed the magnitude and duration of the effects of cocaine on key pressing under the fixed-interval schedule and on adjunctive drinking to be dose-related. Moreover, a given dose of cocaine had diverse effects, depending on the behavior and the time since drug administration.     

Dextrorphan effects on cocaine and brainstem perturbation

Dextrorphan is a noncompetitive blocker of N-methyl-D-aspartate (NMDA) receptors. Since NMDA blockers are known to reduce the locomotor stimulatory and toxic effects of cocaine, it was speculated that dextrorphan would attenuate cocaine-induced behavioral excitatory motor activity associated with and without mechanical perturbation of the brainstem. Technique: Motor activity was recorded following dextrorphan and/or cocaine challenge in 25 SHR rats. Ten were naive subjects. Mini-osmotic pumps delivering cocaine (2.5 mg/0.49 ul/hr) were placed in 15 subjects, and infusion was halted after the third infusion day. On the fifth day either a dextrorphan (25 mg/kg, subcutaneous) or a dextrorphan and cocaine (40 mg/kg, intraperitoneal) challenge was done. Ten rats had bipolar electrode implants in the bilateral brainstem. Five were treated with DC current lesions in each of 12 days over a 3-week period. The effects of brainstem lesions on escape behavior were also evaluated in those five subjects. Results: In the naive subjects, dextrorphan reduced motor activity (P=.0001), whereas combined cocaine and dextrorphan increased motor activity (P=0.04). In lesioned subjects, dextrorphan decreased motor activity (P=0.0001). In electrode implant subjects, combined dextrorphan and cocaine challenge decreased the motor activity (P=0.04). Hyperactivity in the electrode implant group was greater than in the lesioned subjects. Midbrain electrolytic lesions attenuated escape behavior. A variety of behaviors were produced by brainstem lesions. Conclusions: Dextrorphan and brainstem lesions reduced motor hyperactivity and escape behavior. In electrode implant subjects dextrorphan counteracted the expected cocaine excitatory motor effects. Dextrorphan did not activate nor facilitate seizures.     

Synergistic effects of ethanol and cocaine on brain stimulation reward.

The effects of two widely abused drugs, ethanol and cocaine, were examined alone and in combination on intracranial reward processes. In agreement with previous research, higher doses of both cocaine and ethanol alone produced facilitation of behavior maintained by brain stimulation reward. Low intraperitoneal doses of ethanol and cocaine, which alone did not affect performance, were found to reduce stimulation reward threshold and modestly increase response rate. The enhancement of brain stimulation reward by the combination of ethanol and cocaine suggests that both drugs may produce their rewarding effects through common neuronal substrates and that they may potentiate the abuse of each other.     

Behavioral change and consistency across contexts

The degree to which behavior changes across situations is often conflated with the cross-situational consistency of individual differences. The current study assesses the extent of behavioral change and consistency, the relationship between them, and variables associated with behaviors’ differing patterns of change and consistency. Two hundred fifty-six participants were observed in three different, three-person interactions. In line with previous research, behaviors showed a great deal of both change and consistency. Behavioral change across situations was unrelated to the degree to which individual differences in these same behaviors were maintained, demonstrating that behavioral consistency does not imply lack of situational adaptation. Behaviors rated as relatively broad and as relatively automatic showed more consistency; behaviors rated as relatively controlled showed more change.     

Happiness Inducing Behaviors in Everyday Life: An Empirical Assessment of “The How of Happiness”

The frequency of Happiness Inducing Behaviors (HIB) was assessed in a survey of 903 university students; measures of Big Five personality traits and happiness were also obtained. Students reported engaging in many HIBs about 1–3 times per week. Analysis of HIB yielded three factors: Positive/Proactive Behaviors; Spiritual Behaviors; and Physical Health Behaviors. Positive/Proactive behaviors predicted significant additional variance in happiness beyond the variance predictable from Big Five personality traits. Mediation analysis suggested that effects of Big Five traits on happiness may be mediated to varying degrees by engagement in Positive/Proactive Behaviors and Physical Health Behaviors. Additional analyses examined possible moderation of the association between HIB and happiness by gender and Big Five traits; the strength of association between behavior and happiness did not differ between women and men, or across people with different scores on Big Five traits. This study provides additional evidence that naturally occurring behaviors are predictive of happiness in everyday life and confirms earlier findings about the degree to which behaviors mediate effects of Big Five traits on happiness.     

Schedule-induced polydipsia and polyphagia in nondeprived rats reinforced by intracranial stimulation

Five rats, which were neither food nor water deprived, working on fixed or variable-interval schedules of reinforcement for intracranial stimulation developed consistent and excessive patterns of postreinforcement eating or drinking. The gradual deterioration of polydipsia and polyphagia in this situation points to a distinction between the acquisition and maintenance of these behaviors.     

Predictors of champion behaviors in an evidence-based parenting program: A structural equation modeling approach

The importance of champions in the implementation of evidence-based public health programs has been well established. Champions perform a range of behaviors which can have significant influence on the adoption and sustainability of interventions. This study investigates champion behaviors in parenting practitioners with the aim to provide insight into the range and extent that practitioners engage in champion behaviors and to examine predictors of practitioners' champion behaviors using structural equation modeling. Data were collected during a large international implementation survey of 1606 practitioners trained to deliver an evidence-based parenting program, the triple P—Positive Parenting Program. We developed a 13-item Champion Behaviors Scale which was administered alongside other measures of predictors of implementation outcomes. Perceived usefulness of the program was the most important facilitator of both public and personal champion behaviors. Certain desirable features of the program tended to not only be positively associated with the perceived usefulness of the program, but also had a unique impact on practitioners' personal champion behaviors. Higher positions within organizations were linked with more public champion behaviors. Although organizational support was found to be unrelated to champion behaviors in the structural model, it facilitated other predictors of champion behaviors.     

An animal model of excessive eating: schedule-induced hyperphagia in food-satiated rats.

Nineteen rats were maintained throughout the experiment on ad libitum wet mash and water and were trained to press a lever on fixed-interval or fixed-ratio schedules of reinforcement with electrical brain stimulation. Fourteen rats ate at least 150% more mash during intermittent reinforcement sessions than during baseline, massed reinforcement control, and/or extinction sessions. In a 3-hr session, 11 of those 14 consumed more than 22 g of wet mash (13 g dry weight), the equivalent of nearly half an animal's daily food intake. In subsequent control sessions, the electrodes did not support stimulus-bound eating despite attempts to make stimulation parameters optimal. These results indicate that the eating was schedule induced or adjunctive, and suggest that the procedure may provide an animal model of excessive nonregulatory eating that contributes to obesity in humans.     

Effects of prenatal cocaine and genotype on intermale agonistic behavior in Mus musculus

We exposed the pups of three F₁ genotypes of mice to a daily regime of cocaine by injecting their mothers (all C57BL/10J strain) on days 7–18 of gestation with 20 mg/kg subcutaneously. Pups of the cocaine and control groups did not differ on measures of maternal and pup health or size. Male pups were weaned and isolated at 21 days of age and their behaviors measured in an intermale aggression situation at about 80 days of age. Treated and untreated males of each F₁ genotype were paired in dyads with either a C3H/HeJ (hawk-like) or AKR/J (retaliator-like) standard tester male. Standard tester males were not exposed to cocaine. Cocaine treatment alone reduced the overall level of aggression in dyads, and in interaction with genotype or the standard tester it altered the behavior of dyads in all phases of social interaction: the initiation, content, and outcome. Standard testers used as behavioral probes, differentiated cocaine and control males with respect to their stimulus and behavioral qualities. Aggr. Behav. 23:183–196, 1997.© 1997 Wiley-Liss, Inc.     

A comparison of the disturbingness of behaviors related to learning disability and emotional disturbance

Behaviors thought to be characteristic of emotional disturbance or learning disabilities were investigated through ratings of teachers with regard to the relative disturbingness of the behaviors. Obtained differences suggested that behaviors characteristic of emotional disturbance were rated as more disturbing than those of learning disabilities; differences within sets of characteristic behaviors were also indicated. Results are discussed with regard to implications for teacher expectancies and labeling research.     

Daily variation of multiple behaviors in Aplysia fasciata: integration of feeding, reproduction, and locomotion

Daily variations in feeding, reproductive behaviors, and activity level were examined under three conditions: (1) animals had access to food and mates; (2) there was access only to food; (3) neither food nor mates were present. Behaviors differed in amplitude of variations from their daily mean value. Egg-laying had the strongest tendency to be clustered. Amplitude of variations in courtship and swimming was larger than those of immobility, crawling, and feeding, while moving in place was the least clustered behavior. Changes in state affected the tendency to be clustered. When food and mates were present, amplitude of variations became progressively larger for immobility, moving in place, crawling, and swimming. Behaviors differed in the degree to which variations were patterned as a 1/day oscillation. Relatively little of the variability in crawling, moving in place, courtship, and egg-laying was due to a 1/day oscillation under any condition. By contrast, a large proportion of the variability of immobility, swimming, mating, and eating was modulated by a 1/day oscillation in at least one condition. The contribution of a 1/day oscillation to variability differed in the conditions examined. For immobility and swimming, when food and mates were present, the 1/day component of variability became smaller. By contrast, presence of mates led to an increase in the 1/day component of variability modulating feeding. Daily peaks of swimming and feeding were in phase with one another, and out of phase with mating and feeding. The ratio of locomotion to inactivity is constant, independent of change in external conditions. However, this ratio varied throughout the day. When food and mates were absent, variations of immobility and swimming were strongly related to variations in the inactivity ratio. When food and mates were added, this tendency decreased. The data suggest that daily variations in occurrence of behaviors can be accounted for by interactions between oscillators affecting Aplysia behavior and motivational variables. A 1/day oscillator has strong effects on mating, swimming, and immobility. The effect of the oscillator is modified by changes in motivational state.     

Within-Session Changes in Adjunctive and Instrumental Responding

Rats pressed levers for food delivered by several fixed interval schedules. A drinking spout or running wheel was also available during some conditions, but not during others. The rate of lever pressing, drinking and running often changed within experimental sessions. The within-session patterns of lever pressing did not differ when drinking or running was available and when it was not. The correlation between the amount of lever pressing and the amount of drinking or running at a particular time in the session was inconsistently positive or negative. Finding within-session changes in responding for adjunctive behaviors implies that the factors that produce these changes are present for both adjunctive and instrumental behavior. Finding inconsistent correlations between instrumental responding and adjunctive behaviors questions arousal and interference from adjunctive behaviors as explanations for within-session changes in instrumental responding.     

External validity of the new Devereux Adolescent Behavior Rating scales

The discriminant and concurrent validity of the five new scales for the Devereux Adolescent Behavior Rating Scale (DAB) was explored using a heterogeneous sample of psychiatric and substance abuse patients. Consistent with predictions, the substance abuse patients scored higher on the Acting Out Behaviors (AOB) and Heterosexual Interests (HI) scales, and psychiatric patients scored higher on the Psychotic Behaviors scale. Gender differences also were found, including boys being rated higher on Acting Out Behaviors, and girls higher on Heterosexual Interests. The new DAB scales demonstrated sufficient concurrent validity using a thorough record review and a patient rating scale (the Child Behavior Checklist [CBCL]). The Neurotic/Dependent Behaviors scale (NDB) showed a consistent relationship with substance abuse and several other measures of more externalizing behaviors, in addition to the predicted relationships with anxious, tense, and dependent behaviors. The Withdrawn/Timid Behaviors scale (WTB) proved to be a purer measure of internalizing behaviors in both sexes.     

Humanness beliefs about behavior: An index and comparative human-nonhuman behavior judgments

Social psychological research suggests that two distinct dimensions describe lay conceptions of humanness: a species-typical sense (i.e., human nature) and a species-unique sense (i.e., human uniqueness). Although these two senses of humanness have been discerned among psychological traits and states, there has been no systematic research into lay beliefs about the humanness of human behaviors. Using a range of 60 prosocial, nonsocial, and antisocial behaviors, it was demonstrated that people discriminate between species-typical and species-unique behaviors and that the capacity to perform species-unique behaviors distinguishes humans from animals, whereas the capacity to perform species-typical behaviors distinguishes humans from robots. Behaviors that exemplify the two senses of humanness are identified, and data representing rankings, raw scores, and z-scores in two indices of species typicality and species uniqueness are provided. Taken together, these findings expand our understanding of lay conceptions of humanness and provide researchers of humanness with a wider range of validated stimuli to probe the boundaries of humanity.     

ASSESSMENT OF STEREOTYPIC AND SELF-INJURIOUS BEHAVIOR AS ADJUNCTIVE RESPONSES

Certain responses of both humans and nonhumans appear to be maintained indirectly by intermittent reinforcement schedules and have been referred to collectively as adjunctive behavior. Although basic research has examined adjunctive behavior extensively, relatively few studies have been conducted with humans, particularly those with developmental disabilities who often engage in frequent and varied stereotypic behavior. This study assessed possible adjunctive characteristics of self-injurious and stereotypic behaviors using a multielement design containing two types of control conditions. Four subjects who engaged in both self-injurious behavior and stereotypy participated after variables maintaining their self-injury were identified via functional analyses. Each day, subjects were exposed to three 15-min sessions in random order: (a) noncontingent presentation of food on a fixed-time schedule (e.g., FT 30 s), (b) a massed-reinforcement (food) control, and (c) a no-reinforcement control. A variety of fixed-time schedules were examined during different experimental phases. Results of this preliminary study suggested that self-injury was not induced by intermittent reinforcement schedules, whereas the stereotypic behavior of some individuals showed characteristics of adjunctive behavior. The importance of research on adjunctive behavior and suggestions for future studies are discussed.     

External Validity of the New Devereux Adolescent Behavior Rating Scales

The discriminant and concurrent validity of the five new scales for the Devereux Adolescent Behavior Rating Scale (DAB) was explored using a heterogeneous sample of psychiatric and substance abuse patients. Consistent with predictions, the substance abuse patients scored higher on the Acting Out Behaviors (AOB) and Heterosexual Interests (HI) scales, and psychiatric patients scored higher on the Psychotic Behaviors scale. Gender differences also were found, including boys being rated higher on Acting Out Behaviors, and girls higher on Heterosexual Interests. The new DAB scales demonstrated sufficient concurrent validity using a thorough record review and a parent rating scale (the Child Behavior Checklist [CBCL]). The Neurotic/Dependent Behaviors scale (NDB) showed a consistent relationship with substance abuse and several other measures of more externalizing behaviors, in addition to the predicted relationships with anxious, tense, and dependent behaviors. The Withdrawn/Timid Behaviors scale (WTB) proved to be a purer measure of internalizing behaviors in both sexes.