Excitatory conditioning to the interoceptive nicotine stimulus blocks subsequent conditioning to an exteroceptive light stimulus.

Previous research has shown that a nicotine conditional stimulus (CS) can compete with (i.e., overshadow) a brief light CS. Another form of competition, blocking, has not yet been examined with the nicotine CS. Groups of rats were assigned to an element training condition. For the N+ group, during each daily 2-hr element training session, there were ten intravenous nicotine infusions (0.03 mg/kg) followed 30-sec later with 4-s access to sucrose. In the N- group, nicotine and sucrose presentations were explicitly unpaired. The chamber alone group (C alone) had no stimulus presentations. Element training was followed by compound training in all groups. A 30- sec houselight was included during the time between the nicotine infusion and paired sucrose delivery. Non-reinforced element presentations assessed relative control of the goal tracking conditioned response (CR). The N+ group showed a higher proportion of CR control by the nicotine than the light. The opposite pattern was found in the N- and C alone groups indicating that nicotine CS controlled less of the CR than the light. Thus, excitatory conditioning with the nicotine CS blocked later conditioning to the light. This finding adds to literature examining the interaction between interoceptive drug CSs and other environmental stimuli

Behavioral and neuropharmacological characterization of nicotine as a conditional stimulus

In rats, the pharmacological (interoceptive) effects of 0.4 mg/kg nicotine can serve as a conditional stimulus in a Pavlovian conditioning task. Nicotine administration is paired with intermittent access to a liquid sucrose unconditional stimulus; sucrose is withheld on saline sessions. An increase in sucrose receptacle entries (goal tracking) on nicotine sessions indicates conditioning. Rats were trained on a nicotine dose ((-)-1-Methyl-2-(3-pyridyl)pyrrolidine; 0.1, 0.2, or 0.4 mg base/kg, s.c.). Generalization was examined using 0.025, 0.05, 0.1, 0.2, and 0.4 mg/kg nicotine and saline. Some behavioral effects of nicotine have been attributed to dopamine and glutamate. Accordingly, potential blockade of the nicotine cue via the dopamine system was examined by administering (R)-(+)-7-Chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine hydrochloride (SCH-23390; 0.005, 0.01, and 0.03 mg/kg), 3-Chloro-5-ethyl-N-[[(2S)-1-ethyl-2-pyrrolidinyl)methyl]-6-hydroxy-2-methoxy-benzamide hydrochloride (eticlopride; 0.01, 0.03, 0.1, and 0.3 mg/kg), or N-[(1-Butyl-2-pyrrolidinyl)methyl]-4-cyano-1-methoxy-2-naphthalenecarboxamide (nafadotride; 0.03, 0.1, 0.3, 1, and 3 mg/kg) before nicotine. 2-Methyl-6-(phenylethynyl)pyridine hydrochloride (MPEP; 0.3, 1, and 3 mg/kg) and (5S,10R)-(+)-5-Methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine maleate (MK-801; 0.01, 0.03, 0.1, and 0.2 mg/kg; dizocilpine) were used to examine possible glutamatergic components. Substitution tests were conducted with MPEP and nafadotride. Differential conditioned responding was acquired in the 3 groups. Conditioned responding generally decreased as the nicotine test dose moved away from the training dose; responding increased when 0.4 mg/kg trained rats were tested with 0.2 mg/kg. SCH-23390, eticlopride, nafadotride, and MPEP decreased conditioned responding on nicotine at doses that also decreased chamber activity. In contrast, MK-801 decreased goal tracking on nicotine without decreasing chamber activity, indicating a role for N-methyl-D-aspartate receptors in expression of nicotine-evoked conditioned responding

Differential vulnerability to the punishment of cocaine related behaviours: effects of locus of punishment, cocaine taking history and alternative reinforcer availability.

BACKGROUND: The availability of alternative reinforcement has been shown to reduce drug use, but it remains unclear whether it facilitates a reduction or cessation of drug seeking or taking. OBJECTIVES: We compared the effects of punishment of cocaine seeking or taking behaviour after brief or extended cocaine-taking histories when behavioural reallocation was facilitated or not by making available an alternative ingestive reinforcer (sucrose). METHODS: In the first experiment, punishment of either seeking or taking responses was introduced immediately after training on the seeking-taking chained schedule. In the second experiment, punishment of cocaine seeking was introduced after 12 additional days of either 1 or 6 h daily access to cocaine self-administration. In both experiments, beginning 1 week before the introduction of punishment, a subset of rats had concurrent nose poke access to sucrose while seeking or taking cocaine. RESULTS: The presence of an alternative source of reinforcement markedly facilitated behavioural reallocation from punished cocaine taking after acquisition. It also facilitated punishment-induced suppression of cocaine seeking after an extensive cocaine self-administration history likely by prompting goal-directed motivational control over drug use. However, a significant proportion of rats were deemed compulsive-maintaining drug use after an extensive cocaine history despite the presence of abstinence-promoting positive and negative incentives. CONCLUSION: Making available an alternative reinforcer facilitates disengagement from punished cocaine use through at least two different processes but remains ineffective in a subpopulation of vulnerable animals, which continued to seek cocaine despite the aversive consequence of punishment and the presence of the alternative positive reinforcer.This work was supported by the United Kingdom Medical Research Council (MRC) Grant to BJE (G9536855) and was conducted within the MRC/Wellcome Trust Behavioural and Clinical Neuroscience Institute. The authors declare no conflicts of interest.This is the final published version, which can also be found on the publisher's website here: http://download.springer.com/static/pdf/914/art%253A10.1007%252Fs00213-014-3648-5.pdf?auth66=1404987650_ca63ac8614a2994c56b0f619563ee6af&ext=.pd

Nicotine-evoked conditioned responding is dependent on concentration of sucrose unconditioned stimulus

Previous studies have shown that the interoceptive nicotine conditional stimulus (CS) functions similarly to exteroceptive CSs such as lights or environments. For instance, the appetitive conditioned response (CR) evoked when nicotine is repeatedly paired with sucrose presentations (the unconditioned stimulus; US) is sensitive to changes in training dose (CS salience) and the contiguity between the CS effects and sucrose. The current study was conducted to extend this research by examining the possible role of US intensity in CR acquisition and maintenance. Rats were trained using one of four sucrose concentrations: 0, 4, 16, or 32% (w/v). On nicotine sessions (0.4 mg base/kg), rats received 36 deliveries (4 sec each) of their assigned concentration intermittently throughout the session; sucrose was withheld on saline sessions. In all groups, an appetitive goal-tracking CR was acquired at a similar rate. However, the asymptotic CR level varied with sucrose concentration. The magnitude of the CR was increased in rats trained with higher sucrose US concentrations. These findings are consistent with previous Pavlovian conditioning research, and extend the conditions under which the nicotine state functions as an interoceptive conditional stimulus

Responses of Birds and Reptiles in Warrumbungle National Park after the Extensive 2013 Wildfire

In 2013 extensive wildfire burnt 90% (22104 ha) of Warrumbungle National Park in New South Wales, Australia. In 2014-2016 we assessed how species composition and abundance of birds and reptiles varied with fire severity and habitat characteristics. Of 91 bird species observed during surveys of 35 sites, 47 were more often on low severity sites. Bird species composition did not differ among vegetation communities although activity levels (species per 10 minutes) were reduced in woodland on sedimentary geology as compared with volcanic areas. With increasing fire severity bird activity and total number of species detected decreased, and species composition changed. Differences in species composition were due mainly to lower numbers of detections of small to medium-sized insectivores and nectarivores on high severity sites. Results were more complicated for the 36 species of reptiles observed during surveys than for birds. Reptile species composition varied with fire severity, geology, presence of rock outcrops and between vegetation communities. Species richness and abundance of many reptile groups, as well as the total number of individuals, decreased with increasing fire severity, but for reptiles overall and diurnal reptiles, presence of rock outcrops had a stronger effect on number of species and abundance. Differences between reptiles and birds and among reptile groups suggest that fire management for conservation needs to be at a range of scales and consider habitat attributes

Sex Differences in the Behavioural Outcomes of Prenatal Nicotine and Tobacco Exposure

Smoking remains the leading cause of preventable death worldwide. A combination of biological and environmental risk factors make women especially vulnerable to nicotine addiction, making it harder for them to quit smoking. Smoking during pregnancy, therefore, is still a major health concern, with epidemiological data suggesting a role for gestational nicotine exposure in the development of several behavioural disorders. Given there are significant sex-specific behavioural outcomes related to smoking in adolescence and adulthood, it is probable that the behavioural outcomes following gestational nicotine or tobacco exposure are similarly sex-dependent. This is an especially relevant topic as the current landscape of nicotine use shifts toward vaping, a mode of high doses of nicotine delivery that is largely believed to be a safer alternative to cigarettes among the public as well as among pregnant women. Here we review existing clinical and preclinical findings regarding the sex-dependent behavioural outcomes of prenatal nicotine exposure. We also highlight the challenges within this literature, particularly those areas in which further research is necessary to improve consistency within, and between, clinical and preclinical findings

Clinical judgement in violence risk assessment

The present article discusses the three main approaches to violence risk assessment, clinical judgement, actuarial assessment, and structured clinical judgement, informing the reader of the comparative benefits and short-comings of these methods of violence risk assessment. In particular, the present article highlights the controversy within the literature surrounding clinical judgement in comparison to actuarial assessments of violence risk, and proposes that the statistically significant ‘improvements’ of violence prediction when using actuarial scales in comparison to clinical predictions of dangerousness do not necessarily measure the skill of the clinician adequately. Specifically, an assessment of ‘dangerousness’ does not equal a prediction of violent recidivism. It is argued that clinicians are not predictive forecasters of risk, as in actuarial scales, but are, rather, trained to manage risk. In addition, suggestions for future research directions in the field of improving violence risk assessments are made

Applying decision making theory to clinical judgements in violence risk assessment

A considerable proportion of research in the field of violence risk assessment has focused on the accuracy of clinical judgements of offender dangerousness. This has largely been determined through research which compares the accuracy of clinical predictions of offender dangerousness or future violence to mathematical predictions. What has been less researched is the influence of decision making heuristics and biases on clinical judgements of violence risk assessment. The current paper discusses decision making heuristics and biases and applies the theory to clinical judgements in a violence risk assessment context. Based on the current review, it is suggested that in order to improve the effectiveness clinical judgements in violence risk assessment, a greater level of empirical research specifically examining the effects of the heuristics and biases in this context must be conducted, with the possibility of incorporating debiasing training into clinical practice