Does vendor breeding colony influence sign- and goal-tracking in Pavlovian conditioned approach? A preregistered empirical replication

Vendor differences are thought to affect Pavlovian conditioning in rats. After observing possible differences in sign-tracking and goal-tracking behaviour with rats from different breeding colonies, we performed an empirical replication of the effect. 40 male Long-Evans rats from Charles River colonies ‘K72’ and ‘R06’ received 11 Pavlovian conditioned approach training sessions (or “autoshaping”), with a lever as the conditioned stimulus (CS) and 10% sucrose as the unconditioned stimulus (US). Each 58-min session consisted of 12 CS-US trials. Paired rats (n = 15/colony) received the US following lever retraction. Unpaired control rats (n = 5/colony) received sucrose during the inter-trial interval. Next, we evaluated the conditioned reinforcing properties of the CS, by determining whether rats would learn to nose-poke into a new, active (vs. inactive) port to receive CS presentations alone (no sucrose). Preregistered confirmatory analyses showed that during autoshaping sessions, Paired rats made significantly more CS-triggered entries into the sucrose port (i.e., goal-tracking) and lever activations (sign-tracking) than Unpaired rats did, demonstrating acquisition of the CS-US association. Confirmatory analyses showed no effects of breeding colony on autoshaping. During conditioned reinforcement testing, analysis of data from Paired rats alone showed significantly more active vs. inactive nosepokes, suggesting that in these rats, the lever CS acquired incentive motivational properties. Analysing Paired rats alone also showed that K72 rats had higher Pavlovian Conditioned Approach scores than R06 rats did.  Thus, breeding colony can affect outcome in Pavlovian conditioned approach studies, and animal breeding source should be considered as a covariate in such work

Animal research is saving lives, but funding is needed to improve welfare: Submission to the New South Wales parliamentary inquiry

Many kinds of animal research are occurring in New South Wales (NSW), with biomedical research among the most prominent. As behavioural neuroscientists, we study the neural mechanisms of motivation and cognition in rodents, which is important for developing new treatments for a range of psychological disorders, such as substance use disorder, as well as neurodegenerative diseases such as Alzheimer’s. The welfare and wellbeing of the animals we study is of critical importance, not only to ensure the quality of our data but to our sense of morality as compassionate human beings. Biomedical animal research is highly regulated and the pharmacological and biological tools we use pose negligible risks to the public. Meanwhile, our research brings enormous benefits to NSW by building expertise and supporting biotechnology companies. Although research on complex behaviours cannot be replaced by non-animal procedures, we believe that there is much scope for refinement and improvement in animal welfare in NSW. For example, investing in a local breeding facility to produce animals used in NSW research projects would significantly reduce the stress associated with importing animals from interstate or overseas. Additionally, standard animal housing could be improved through targeted and ongoing investment to refit animal facilities and support additional caretaker and veterinary staff to provide higher degrees of welfare

Decynium-22 affects behavior in the zebrafish light/dark test

Decynium-22 (D-22) is an inhibitor of the uptake2 system of monoamine clearance, resulting in increased levels of dopamine and norepinephrine (and in some cases serotonin) in the nervous system and elsewhere. Uptake2 is mediated by low-affinity, high-capacity transporters that are inhibited by glucocorticoids, suggesting a mechanism of fast glucocorticoid-monoamine interaction in the brain and a possible target for antidepressants. D-22 dose-dependently increased anxiety-like behavior in adult zebrafish exposed to the light/dark test, monotonically increasing scototaxis (dark preference), but affecting risk assessment with an inverted-U-shaped response. These results suggest that the uptake2 system has a role in defensive behavior in zebrafish, presenting a novel mechanism by which stress and glucocorticoids could produce fast neurobehavioral adjustments in vertebrates

Insular cortex dopamine 1 and 2 receptors in methamphetamine conditioned place preference and aversion: Age and sex differences

Rodent studies have proposed that adolescent susceptibility to substance use is at least partly due to adolescents experiencing reduced aversive effects of drugs compared to adults. We thus investigated methamphetamine (meth) conditioned place preference/aversion (CPP/CPA) in adolescent and adult mice in both sexes using a high dose of meth (3 mg/kg) or saline as controls. Mice tagged with green-fluorescent protein (GFP) at Drd1a or Drd2 were used so that dopamine receptor 1 (D1) and 2 (D2) expression within the insular cortex (insula) could be quantified. There are sex differences in how the density of D1+ and D2+ cells in the insula changes across adolescence that may be related to drug-seeking behaviors. Immunohistochemistry followed by stereology were used to quantify the density of cells with c-Fos and/or GFP in the insula. Unexpectedly, mice showed huge variability in behaviors including CPA, CPP, or no preference or aversion. Females were less likely to show CPP compared to males, but no age differences in behavior were observed. Conditioning with meth increased the number of D2 + cells co-labelled with c-Fos in adults but not in adolescents. D1:D2 ratio also sex- and age-dependently changed due to meth compared to saline. These findings suggest that reduced aversion to meth is unlikely an explanation for adolescent vulnerability to meth use. Sex- and age-specific expressions of insula D1 and D2 are changed by meth injections, which has implications for subsequent meth use

Associative processes in addiction relapse models: A review of their Pavlovian and instrumental mechanisms, history, and terminology

Animal models of relapse to drug-seeking have borrowed heavily from associative learning approaches. In studies of relapse-like behaviour, animals learn to self-administer drugs then receive a period of extinction during which they learn to inhibit the operant response. Several triggers can produce a recovery of responding which form the basis of a variety of models. These include the passage of time (spontaneous recovery), drug availability (rapid reacquisition), extinction of an alternative response (resurgence), context change (renewal), drug priming, stress, and cues (reinstatement). In most cases, the behavioural processes driving extinction and recovery in operant drug self-administration studies are similar to those in the Pavlovian and behavioural literature, such as context effects. However, reinstatement in addiction studies have several differences with Pavlovian reinstatement, which have emerged over several decades, in experimental procedures, associative mechanisms, and terminology. Interestingly, in cue-induced reinstatement, drug-paired cues that are present during acquisition are omitted during lever extinction. The unextinguished drug-paired cue may limit the model's translational relevance to cue exposure therapy and renders its underlying associative mechanisms ambiguous. We review major behavioural theories that explain recovery phenomena, with a particular focus on cue-induced reinstatement because it is a widely used model in addiction. We argue that cue-induced reinstatement may be explained by a combination of behavioural processes, including reacquisition of conditioned reinforcement and Pavlovian to Instrumental Transfer. While there are important differences between addiction studies and the behavioural literature in terminology and procedures, it is clear that understanding associative learning processes is essential for studying relapse

mGlu5: A double-edged sword for aversive learning related therapeutics

Aversive memories underlie many types of anxiety disorders. One area of research to more effectively treat anxiety disorders has therefore been identifying pharmacological targets to affect memory processes. Among these targets, the metabotropic glutamate 5 receptor (mGlu5) has received attention due to the availability of drugs to utilize its role in learning and memory. In this review, we highlight preclinical studies examining the role of mGlu5 at various stages of aversive learning and its inhibition via extinction in order to gain a better understanding of its therapeutic potential. We suggest that mGlu5 has distinct roles at different stages of memory that not only makes it a tricky target, but a double-edged sword as a therapeutic. However, the selective involvement of mGlu5 in different memory stages allows for certain precision that could be harnessed clinically. We therefore suggest potential applications, limitations, and pitfalls when considering use of mGlu5 modulators as therapeutics. In addition, we recommend future studies to address important gaps in this literature, such as sex and age factors in light of anxiety disorders being more prevalent in those demographics

The perception of reproducibility in a small cohort of scientists in Europe

Reproducibility is an essential feature of all scientific outcomes. Scientific evidence can only reach its true status as reliable if replicated, but the results of well-conducted replication studies face an uphill battle to be performed, and little attention and dedication have been put into publishing the results of replication attempts. Therefore, we asked a small cohort of researchers about their attempts to replicate results from other groups, as well as from their own laboratories, and their general perception of the issues concerning reproducibility in their field. We also asked how they perceive the venues, i.e. journals, to communicate and discuss the results of these attempts. To this aim we pre-registered and shared a questionnaire among scientists at diverse levels. The results indicate that, in general, replication attempts of their own protocols are quite successful (with over 80% reporting not or rarely having problems with their own protocols). Although the majority of respondents tried to replicate a study or experiment from other labs (75.4%), the median successful rate was scored at 3 (in a 1-5 scale), while the median for the general estimation of replication success in their field was found to be 5 (in a 1-10 scale). The majority of respondents (70.2%) also perceive journals as unwelcoming of replication studies

Orexin neuron activity in mating mice - a pilot study

Mating behaviours affect hypothalamic orexin/hypocretin neurons and vice versa. However, activity of orexin neurons has not been recorded during mating before. We report an anecdotal dataset of freely-moving miniature microscope recordings of orexin neuron activity during mating behaviours, as well as an oral sexual encounter previously undocumented in mice. Across the orexin neuron population in the male, firing rates were maximally diverse during ejaculation, similarly diverse though weaker during intromission, and inverse to this during anterior thrusting. In the female mouse, orexin neurons tended to decrease firing during intromission after a transient increase. We provide this brief dataset for re-use, to enable further studies of these rare behaviours with challenging surgical preparations

Cannabinoid treatment of opiate addiction

Opioid abuse is a growing global problem. Current therapies for opioid abuse target withdrawal symptoms and have several adverse side effects. There are no treatments to address opioid-induced neural adaptations associated with abuse and addiction. Preclinical research demonstrates interactions between the endogenous opioid and cannabinoid systems, suggesting that cannabinoids may be used to treat opioid addiction and dependence. The aim of this review is to assess how cannabinoids affect behavioural and molecular measures of opioid dependence and addiction-like behaviour in animal models. It appears that cannabidiol and cannabinoid receptor 1 (CB1R) antagonists have potential for treating drug-craving and drug-seeking behaviour, based on evidence from preclinical animal models. Ligands which inhibit the action of cannabinoid degradation enzymes also show promise in reducing opioid withdrawal symptoms and opioid self-administration in rodents. Agonists of CB1R could be useful for treating symptoms of opioid withdrawal; however, the clinical utility of these drugs is limited by side effects, the potential for cannabinoid addiction and an increase in opiate tolerance induced by cannabinoid consumption. The mechanisms by which cannabinoids reduce opioid addiction-relevant behaviours include modulation of cannabinoid, serotonin, and dopamine receptors, as well as signalling cascades involving ERK-CREB-BDNF and peroxisome proliferator-activated receptor-α. Identifying the receptors involved and their mechanism of action remains a critical area of future research

How we are building Neuroanatomy and Behaviour for rigorous and open science

Neuroanatomy and Behaviour was founded to be a journal for rigorous and open science. In 2021, all of the empirical papers published engaged in at least one open science practice, such as open data or open protocols. The papers published have been carefully reviewed by two experts, but may also be sent to additional specialist reviewers for specific tasks, such as checking references or statistical approaches. In 2021, Neuroanatomy and Behaviour reached a key milestone and was accepted into the Directory of Open Access Journals, the world’s leading database of trustworthy open access journals. As we look towards 2022, we will continue improving our publication processes and working to share quality neuroscience without financial barriers for authors or readers