Rituals, stereotypy and compulsive behavior in animals and humans

Characterising repetitive behaviours in children and adolescents with Down syndrome

BACKGROUND

Individuals with intellectual disability, including people with Down syndrome (DS), often exhibit restricted and repetitive behaviours (RRBs). However, RRBs have not been deeply characterised in children and adolescents with DS.

METHOD

The study encompassed a cohort of 151 participants aged 4 to 18 years with DS. RRBs were assessed utilising the Repetitive Behaviour Scale-Revised. Additionally, data pertaining to cognitive and adaptive functioning, linguistic abilities, sleep patterns and emotional/behavioural issues were gathered.

RESULTS

Self-injurious behaviours were reported less frequently whereas parents most commonly endorsed items related to behaviours associated with the need for sameness and ritualistic behaviours. We observed very few gender differences, whereas some age-related differences emerged, with adolescents exhibiting higher scores in items related with higher-level RRBs. The analysis of the association between RRBs and clinical features revealed that RRBs were associated with parent-reported sleep difficulties, as well as with internalising and externalising problems. We also observed a negative correlation with IQ whereas associations with adaptive skills emerged mainly for lower-level RRBs, such as motor stereotypies. Finally, RRBs were negatively associated with linguistic abilities, both expressive and receptive.

CONCLUSIONS

RRBs in children and adolescents with DS are of significant clinical interest due to their associations with various clinical dimensions. Therefore, psychological and neuropsychiatric assessment should include an accurate evaluation of RRBs for young people with DS.

The relationship between obsessive-compulsive symptoms and real-life functioning in schizophrenia: New insights from the multicenter study of the Italian Network for Research on Psychoses

BACKGROUND

Although obsessive-compulsive disorder (OCD) is highly prevalent in schizophrenia, its relationship with patients' real-life functioning is still controversial.

METHODS

The present study aims at investigating the prevalence of OCD in a large cohort of non-preselected schizophrenia patients living in the community and verifying the relationship of OCD, as well as of other psychopathological symptoms, with real-life functioning along a continuum of OCD severity and after controlling for demographic variables.

RESULTS

A sample of 327 outpatients with schizophrenia was enrolled in the study and collapsed into three subgroups according to OCD severity (subclinical, mild-moderate, severe). A series of structural equation modeling (SEM) was performed to analyze in each subgroup the association of obsessive-compulsive symptoms with real-life functioning, assessed through the Specific Levels of Functioning Scale and the UCSD Performance-Based Skills Assessment. Moreover, latent profile analysis (LPA) was performed to infer latent subpopulations. In the subclinical OCD group, obsessive-compulsive symptoms (OCS) were not associated with functioning, whereas in the mild-moderate OCD group, they showed a positive relationship, particularly in the domains of work and everyday life skills. The paucity of patients with severe OCD did not allow performing SEM analysis in this group. Finally, LPA confirmed a subgroup with mild-moderate OCS and more preserved levels of functioning.

CONCLUSIONS

These findings hint at a positive association between mild-moderate OCD and real-life functioning in individuals with schizophrenia and encourage a careful assessment of OCD in personalized programs to sustain daily life activities.

Impact of Benzodiazepines and Illness Duration on Obsessive-Compulsive Disorder during COVID-19 in Italy: Exploring Symptoms' Evolutionary Benefits

Obsessive-compulsive disorder (OCD) is believed to follow a waxing and waning course, often according to environmental stressors. During the COVID-19 pandemic, pre-existing OCD symptoms were reported to increase and to change from checking to washing behaviors, while new-onset symptoms were predominantly of the hoarding type. In the present study, we followed the evolution of OCD symptoms, anxiety, depression, and insights of illness in forty-six OCD patients throughout the pandemic. Clinical measures were collected at four different time points before and during the COVID-19 pandemic in Italy. Within-subject comparisons were used to compare clinical scale scores across time, and correlations were examined between patients' baseline characteristics and changes in clinical scores. We found that all clinical measures increased during the first Italian lockdown with respect to the pre-pandemic values. Anxiety decreased during the temporary elimination of restriction provisions, whereas the severity of OCD symptoms and insight returned to pre-pandemic values during the second mandatory lockdown. These results were observed only in two sub-groups of patients: those taking benzodiazepines and those with shorter illness duration. Our findings suggest the need for additional clinical attention to these specific sub-groups of OCD patients in case of particularly distressing circumstances while pointing to a possible adaptive role of their OCD symptoms when the environment requires a higher care of hygiene and an extraordinary supply of essential resources.

Rhesus monkeys exhibiting spontaneous ritualistic behaviors resembling obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD) is a chronic and debilitating psychiatric disorder that affects ∼2%-3% of the population globally. Studying spontaneous OCD-like behaviors in non-human primates may improve our understanding of the disorder. In large rhesus monkey colonies, we found 10 monkeys spontaneously exhibiting persistent sequential motor behaviors (SMBs) in individual-specific sequences that were repetitive, time-consuming and stable over prolonged periods. Genetic analysis revealed severely damaging mutations in genes associated with OCD risk in humans. Brain imaging showed that monkeys with SMBs had larger gray matter (GM) volumes in the left caudate nucleus and lower fractional anisotropy of the corpus callosum. The GM volume of the left caudate nucleus correlated positively with the daily duration of SMBs. Notably, exposure to a stressor (human presence) significantly increased SMBs. In addition, fluoxetine, a serotonergic medication commonly used for OCD, decreased SMBs in these monkeys. These findings provide a novel foundation for developing better understanding and treatment of OCD.

A Longitudinal Study of Parenting Conditions on Two Adult, North American River Otters' (Lontra Canadensis) Repetitive Behavior

Captive animal welfare research focuses on husbandry, enrichment, enclosure space, visitor effects, and opportunities for species-typical behavior (e.g., foraging, territoriality, and social interaction). And yet, one of the most biologically relevant opportunities for species-typical behavior, parenting, has received little attention. The goal of this longitudinal investigation was to explore the differential variability of repetitive behavior across three parenting conditions (i.e., No parenting, parenting, and foster parenting) among captive, wild-rescued, North American river otters. This study represents anatural ABAC design, the conditions reflect differential parenting phases: No parenting (A), Parenting biological pups (B), and Alloparenting nonbiological pups (C). The behavior of two adult North American river otters at the Oregon Zoo were observed from April2016 through March2020 during the different parenting contexts. The frequency of repetitive behaviors was lowest during parenting and highest during the non-parenting conditions. Although data for season, weather, and visitor variables were also collected throughout this study; parenting condition was the only consistent moderator of abnormal repetitive behavior observed.

Behavioral restriction, lorazepam, and escitalopram uniquely influence the expression of naturalistic stereotypy in deer mice: perspectives on anxiety- and compulsive-like behavior

Introduction: Stereotypical expression in laboratory-housed rodents can be explained by different motivational, coping, and motor dysfunction theories. Here, we aimed to explore the neurocognitive underpinnings of high stereotypical (HS) expression in deer mice (Peromyscus maniculatus bairdii), previously proposed as a model system of compulsive-like behavioral persistence. Specifically, we aimed to establish whether HS behavior is related to an underlying escape-related trigger. Methods: One-hundred and sixteen deer mice were classified as either non-stereotypical (NS) or HS. Mice of each cohort were further subdivided and exposed to either sub-acute (3-day) or chronic (25-day) behavioral restriction (R), and high-dose escitalopram (ESC), lorazepam (LOR), alone and in combination with R (ESC+R and LOR+R, respectively). Mice were reassessed for stereotypical behavior at both time points. Results: Our results indicate that HS behavior is likely not temporally and functionally related to an anxiogenic trigger, i.e., R, but rather that HS is associated with parallel changes in anxiogenic feedback processing. We also show that chronic R alone significantly decreased the time spent in expressing HS behavior in animals of the HS, but not NS phenotype. Discussion: This points to the possibility that HS-expressing mice represent a subgroup of P. maniculatus bairdii in which unique interactions between neurobiology and processes of gradual behavioral organization, may contribute to the expression of the typical behaviors observed in this cohort. Collectively, our findings highlight the value of the deer mouse model system to investigate the potential neurocognitive mechanisms that may underlie the development of persistent phenotypes that can likely not be explained entirely by current theories.

The motor profile of obsessive-compulsive rituals: psychopathological and evolutionary implications

BACKGROUND

Studies investigating obsessive-compulsive disorder from an ethological approach have highlighted a specific motor pattern of compulsive rituals with respect to corresponding ordinary behaviors. Particularly, compulsive motor profile is built through the repetition of acts, with prevalence of nonfunctional ones and redirection of attention to its basic structural units. These formal features would characterize ritual behavior throughout evolution, from nonhuman animals to human cultures. However, no study to date has investigated a possible relationship between such motor profile and underlying psychopathology. Therefore, the first objective of the study was to confirm previous findings on a larger sample size of obsessive patients; the second objective was to elucidate whether motor profile might be associated with obsessive-compulsive psychopathology and/or prepsychotic symptoms of schizophrenia.

METHODS

Twenty-one obsessive-compulsive outpatients provided a videotape of their rituals. An equal number of healthy controls, matched for sex and age, were registered for corresponding ordinary acts. Obsessive patients were administered the Yale-Brown Obsessive-Compulsive Scale, the Brown Assessment of Beliefs Scale, the Hamilton Rating Scale for Depression, and the Frankfurt Complaint Questionnaire.

RESULTS

The results of the present study confirm that ritual compulsions present a specific motor structure characterized by repetition of both functional and nonfunctional acts and their longer duration. Such a motor pattern is independent from obsessive-compulsive psychopathology, whereas it results specifically associated with prepsychotic symptoms of schizophrenia.

CONCLUSIONS

We argue that this association may reflect the adaptive significance of ritual behavior across evolution, that is, its homeostatic function in conditions of unpredictability.

Functional Constructivism Approach to Multilevel Nature of Bio-Behavioral Diversity

Attempts to revise the existing classifications of psychiatric disorders (DSM and ICD) continue and highlight a crucial need for the identification of biomarkers underlying symptoms of psychopathology. The present review highlights the benefits of using a Functional Constructivism approach in the analysis of the functionality of the main neurotransmitters. This approach explores the idea that behavior is neither reactive nor pro-active, but constructive and generative, being a transient selection of multiple degrees of freedom in perception and actions. This review briefly describes main consensus points in neuroscience related to the functionality of eight neurochemical ensembles, summarized as a part of the neurochemical model Functional Ensemble of Temperament (FET). None of the FET components is represented by a single neurotransmitter; all neurochemical teams have specific functionality in selection of behavioral degrees of freedom and stages of action construction. The review demonstrates the possibility of unifying taxonomies of temperament and classifications of psychiatric disorders and presenting these taxonomies formally and systematically. The paper also highlights the multi-level nature of regulation of consistent bio-behavioral individual differences, in line with the concepts of diagonal evolution (proposed earlier) and Specialized Extended Phenotype.

Effort-motivated behavior resolves paradoxes in appetitive conditioning

Motivated behavior has long been studied by psychologists, ethologists, and neuroscientists. To date, many scientists agree with the view that cue and reward attraction is the product of a dopamine-dependent unconscious process called incentive salience or "wanting". This process allows the influence of multiple factors such as hunger and odors on motivational attraction. In some cases, however, the resulting motivated behavior differs from what the incentive salience hypothesis would predict. I argue that seeking behavior under reward uncertainty illustrates this situation: Organisms do not just "want" (appetite-based attraction) cues that are inconsistent or associated with reward occasionally, they "hope" that those cues will consistently predict reward procurement in the ongoing trial. Said otherwise, they become motivated to invest time and energy to find consistent cue-reward associations despite no guarantee of success (effort-based attraction). A multi-test comparison of performance between individuals trained under uncertainty and certainty reveals behavioral paradoxes suggesting that the concept of incentive salience cannot fully account for responding to inconsistent cues. A mathematical model explains how appetite-based and effort-based attractions might combine their effects.

A Neural Network Reveals Motoric Effects of Maternal Preconception Exposure to Nicotine on Rat Pup Behavior: A New Approach for Movement Disorders Diagnosis

Neurodevelopmental disorders can stem from pharmacological, genetic, or environmental causes and early diagnosis is often a key to successful treatment. To improve early detection of neurological motor impairments, we developed a deep neural network for data-driven analyses. The network was applied to study the effect of maternal nicotine exposure prior to conception on 10-day-old rat pup motor behavior in an open field task. Female Long-Evans rats were administered nicotine (15 mg/L) in sweetened drinking water (1% sucralose) for seven consecutive weeks immediately prior to mating. The neural network outperformed human expert designed animal locomotion measures in distinguishing rat pups born to nicotine exposed dams vs. control dams (87 vs. 64% classification accuracy). Notably, the network discovered novel movement alterations in posture, movement initiation and a stereotypy in "warm-up" behavior (repeated movements along specific body dimensions) that were predictive of nicotine exposure. The results suggest novel findings that maternal preconception nicotine exposure delays and alters offspring motor development. Similar behavioral symptoms are associated with drug-related causes of disorders such as autism spectrum disorder and attention-deficit/hyperactivity disorder in human children. Thus, the identification of motor impairments in at-risk offspring here shows how neuronal networks can guide the development of more accurate behavioral tests to earlier diagnose symptoms of neurodevelopmental disorders in infants and children.

Electroencephalographic Correlates of Obsessive-Compulsive Disorder

This chapter reviews EEG research in Obsessive-Compulsive Disorder (OCD), focusing on Event-Related Potentials (ERPs) such as the Contingent Negative Variation, N2, Error-Related Negativity, the feedback Error-Related Negativity and the Readiness Potential and their neural bases. The functional significance, utility and correlation of these ERPs with OCD symptoms will be discussed, alongside novel theories for integrating the research findings. I will consider hypotheses including goal-directed behaviour, overreliance on habits, dissociations between action and knowledge, and excessive intolerance of uncertainty in the context of EEG studies, thus providing a comprehensive framework of the electroencephalographic literature concerning OCD.

Proximate and ultimate causes of ritual behavior

Ritual behaviour, intended as a specific, repetitive and rigid form of action flow, appears both in social and non-social environmental contexts, representing an ubiquitous phenomenon in animal life including human individuals and cultures. The purpose of this contribution is to investigate an evolutionary continuum in proximate and ultimate causes of ritual behavior. A phylogenetic homology in proximal mechanisms can be found, based on the repetition of genetically programmed and/or epigenetically acquired action patterns of behavior. As far as its adaptive significance, ethological comparative studies show that the tendency to ritualization is driven by the unpredictability of social or ecological environmental stimuli. In this perspective, rituals may have a "homeostatic" function over unpredictable environments, as further highlighted by psychopathological compulsions. In humans, a circular loop may have occurred among ritual practices and symbolic activity to deal with a novel culturally-mediated world. However, we suggest that the compulsion to action patterns repetition, typical of all rituals, has a genetically inborn motor foundation, thus precognitive and pre-symbolic. Rooted in such phylogenetically conserved motor structure (proximate causes), the evolution of cognitive and symbolic capacities have generated the complexity of human rituals, though maintaining the original adaptive function (ultimate causes) to cope with unpredictable environments.

Mother Schema, Obstetric Dilemma, and the Origin of Behavioral Modernity

What triggered the emergence of uniquely human behaviors (language, religion, music) some 100,000 years ago? A non-circular, speculative theory based on the mother-infant relationship is presented. Infant "cuteness" evokes the infant schema and motivates nurturing; the analogous mother schema (MS) is a multimodal representation of the carer from the fetal/infant perspective, motivating fearless trust. Prenatal MS organizes auditory, proprioceptive, and biochemical stimuli (voice, heartbeat, footsteps, digestion, body movements, biochemicals) that depend on maternal physical/emotional state. In human evolution, bipedalism and encephalization led to earlier births and more fragile infants. Cognitively more advanced infants survived by better communicating with and motivating (manipulating) mothers and carers. The ability to link arbitrary sound patterns to complex meanings improved (proto-language). Later in life, MS and associated emotions were triggered in ritual settings by repetitive sounds and movements (early song, chant, rhythm, dance), subdued light, dull auditory timbre, psychoactive substances, unusual tastes/smells and postures, and/or a feeling of enclosure. Operant conditioning can explain why such actions were repeated. Reflective consciousness emerged as infant-mother dyads playfully explored intentionality (theory of mind, agent detection) and carers predicted and prevented fatal infant accidents (mental time travel). The theory is consistent with cross-cultural commonalities in altered states (out-of-body, possessing, floating, fusing), spiritual beings (large, moving, powerful, emotional, wise, loving), and reports of strong musical experiences and divine encounters. Evidence is circumstantial and cumulative; falsification is problematic.

A Psycho-Behavioral Perspective on Modelling Obsessive-Compulsive Disorder (OCD) in Animals: The Role of Context

Obsessive-compulsive disorder is a heterogeneous and debilitating condition, characterized by intrusive thoughts and compulsive repetition. Animal models of OCD are important tools that have the potential to contribute significantly to our understanding of the condition. Although there is consensus that pre-clinical models are valuable in elucidating the underlying neurobiology in psychiatric disorders, the current paper attempts to prompt ideas on how interpretation of animal behavior can be expanded upon to more effectively converge with the human disorder. Successful outcomes in psychopharmacology involve rational design and synthesis of novel compounds and their testing in well-designed animal models. As part of a special journal issue on OCD, this paper will 1) review the psychobehavioral aspects of OCD that are of importance on how the above ideas can be articulated, 2) briefly elaborate on general issues that are important for the development of animal models of OCD, with a particular focus on the role and importance of context, 3) propose why translational progress may often be less than ideal, 4) highlight some of the significant contributions afforded by animal models to advance understanding, and 5) conclude by identifying novel behavioral constructs for future investigations that may contribute to the face, predictive and construct validity of OCD animal models. We base these targets on an integrative approach to face and construct validity, and note that the issue of treatment-resistance in the clinical context should receive attention in current animal models of OCD.

Construct Validity and Cross Validity of a Test Battery Modeling Autism Spectrum Disorder (ASD) in Mice

Modeling in other organism species is one of the crucial stages in ascertaining the association between gene and psychiatric disorder. Testing Autism Spectrum Disorder (ASD) in mice is very popular but construct validity of the batteries is not available. We presented here the first factor analysis of a behavioral model of ASD-like in mice coupled with empirical validation. We defined fourteen measures aligning mouse-behavior measures with the criteria defined by DSM-5 for the diagnostic of ASD. Sixty-five mice belonging to a heterogeneous pool of genotypes were tested. Reliability coefficients vary from .68 to .81. The factor analysis resulted in a three- factor solution in line with DSM criteria: social behavior, stereotypy and narrowness of the field of interest. The empirical validation with mice sharing a haplo-insufficiency of the zinc-finger transcription factor TSHZ3/Tshz3 associated with ASD shows the discriminant power of the highly loaded items.

Automated Detection of Repetitive Motor Behaviors as an Outcome Measurement in Intellectual and Developmental Disabilities

Repetitive sensory motor behaviors are a direct target for clinical treatment and a potential treatment endpoint for individuals with intellectual or developmental disabilities. By removing the burden associated with video annotation or direct observation, automated detection of stereotypy would allow for longer term monitoring in ecologic settings. We report automated detection of common stereotypical motor movements using commercially available accelerometers affixed to the body and a generalizable detection algorithm. The method achieved a sensitivity of 80% for body rocking and 93% for hand flapping without individualized algorithm training or foreknowledge of subject's specific movements. This approach is well-suited for implementation in a continuous monitoring system outside of a clinical setting.

Incentive hope: A default psychological response to multiple forms of uncertainty

Our target article proposes that a new concept - incentive hope - is necessary in the behavioral sciences to explain animal foraging under harsh environmental conditions. Incentive hope refers to a specific motivational mechanism in the brain - considered only in mammals and birds. But it can also be understood at a functional level, as an adaptive behavioral strategy that contributes to improve survival. Thus, this concept is an attempt to bridge across different research fields such as behavioral psychology, reward neuroscience, and behavioral ecology. Many commentaries suggest that incentive hope even could help understand phenomena beyond these research fields, including food wasting and food sharing, mental energy conservation, diverse psychopathologies, irrational decisions in invertebrates, and some aspects of evolution by means of sexual selection. We are favorable to such extensions because incentive hope denotes an unconscious process capable of working against many forms of adversity; organisms do not need to hope as a subjective feeling, but to behave as if they had this feeling. In our response, we carefully discuss each suggestion and criticism and reiterate the importance of having a theory accounting for motivation under reward uncertainty.

An experimental examination of object-directed ritualized action in children across two cultures

Ritualized actions are common in daily life, and prevalent across cultures. Adults have been shown, under experimental conditions, to treat objects subjected to ritualized action as special and different relative to objects subjected to non-ritualized action. Similarly, children as young as 4, are sensitive to ritualized actions–frequently reproducing such actions at high fidelity. The current cross-cultural experiment attempts to extend existing findings among two culturally distinct groups of children with regard to object-directed rituals. We predicted that children’s preference for a reward would be influenced by ritualized action (but not non-ritualized action). Over two trials we presented children in Australia (N = 93; mean age = 6.03 years, SD = 2.07 years) and Vanuatu (N = 109; mean age = 6.13 years, SD = 1.96 years) with two identical rewards, which was either subjected to ritualized action or non-ritualized action. Contrary to previous findings among adults, ritualized action did not influence children’s preference for a reward. We frame the current results in the context of socially relevant group rituals, and discuss the implications for both wider theory and methods. We conclude with a call for pre-registered replications.

Behaviour-Based Husbandry-A Holistic Approach to the Management of Abnormal Repetitive Behaviors

The field of zoo animal welfare science has developed significantly over recent years. However despite this progress in terms of scientific research, globally, zoo animals still face many welfare challenges. Recently, animal welfare frameworks such as the five domains or five needs have been developed and suggested to improve the welfare of zoo animals, but without practical guidance, such tools may remain abstract from the daily experience of zoo animals. Similarly specific practical strategies such as those for enrichment development exist, but their lack of holistic integration with other aspects of animal husbandry and behavioral medicine means that overall, good zoo animal welfare may still be lacking. This paper outlines some of the barriers to implementing improved zoo animal welfare in practice, and proposes a new strategy for the development of behavioral husbandry routines focused on the management and mitigation of abnormal repetitive behaviors. Focusing on enhancing zoo animal welfare by integrating aspects of ecology, ethology and clinical animal behavior into a practical and comprehensive approach to behavior-based husbandry.

Peromyscus maniculatus bairdii as a naturalistic mammalian model of obsessive-compulsive disorder: current status and future challenges

Obsessive-compulsive disorder (OCD) is a prevalent and debilitating condition, characterized by intrusive thoughts and repetitive behavior. Animal models of OCD arguably have the potential to contribute to our understanding of the condition. Deer mice (Permomyscus maniculatus bairdii) are characterized by stereotypic behavior which is reminiscent of OCD symptomology, and which may serve as a naturalistic animal model of this disorder. Moreover, a range of deer mouse repetitive behaviors may be representative of different compulsive-like phenotypes. This paper will review work on deer mouse behavior, and evaluate the extent to which this serves as a valid and useful model of OCD. We argue that findings over the past decade indicate that the deer mouse model has face, construct and predictive validity.

Psychotomimetic-like behavioral effects of memantine in the mouse

A single administration of mice with memantine (1-amino-3,5-dimethyladamantane), a glutamatergic N-methyl-d-aspartate (NMDA) receptor antagonist, induced stereotyped behaviors in dose- and time-dependent manners. The predominant behavioral component of the stereotypy was a continuous, exaggerated sniffing which was accompanied by persistent locomotion. In contrast, a psychostimulant methamphetamine (METH) predominantly induced a stereotyped biting and other forms of intense stationary stereotypical behaviors. Memantine-induced stereotyped sniffing was attenuated by pretreatment with haloperidol, a dopamine D₂ receptor antagonist, in a dose-dependent manner. The memantine-induced stereotyped sniffing was also attenuated by pretreatment with betahistine (2-[2-(methylamino)ethyl]pyridine), an agent which increases histamine turnover and releases histamine in the brain. These observations suggest that memantine might induce stereotypies through neuronal mechanisms that are somewhat different from those of METH, but still overlap to a certain extent, since memantine-induced stereotypies can be attenuated by the mechanisms that also suppress METH-induced stereotypy. Importantly, these data suggests that the effects of memantine may be more limited to the ventral striatum including nucleus accumbens than those of METH, which is associated with dorsal striatal stimulation at high doses. In this respect memantine may also have pharmacological properties such as compartmentation (i.e. brain distribution) and neuronal mechanisms different from those of other NMDA receptor antagonists, such as ketamine, which may have important implications for therapeutic uses of these drugs.

Obsessive-compulsive disorder: Insights from animal models

Research with animal models of obsessive-compulsive disorder (OCD) shows the following: (1) Optogenetic studies in mice provide evidence for a plausible cause-effect relation between increased activity in cortico-basal ganglia-thalamo-cortical (CBGTC) circuits and OCD by demonstrating the induction of compulsive behavior with the experimental manipulation of the CBGTC circuit. (2) Parallel use of several animal models is a fruitful paradigm to examine the mechanisms of treatment effects of deep brain stimulation in distinct OCD endophenotypes. (3) Features of spontaneous behavior in deer mice constitute a rich platform to investigate the neurobiology of OCD, social ramifications of a compulsive phenotype, and test novel drugs. (4) Studies in animal models for psychiatric disorders comorbid with OCD suggest comorbidity may involve shared neural circuits controlling expression of compulsive behavior. (5) Analysis of compulsive behavior into its constitutive components provides evidence from an animal model for a motivational perspective on OCD. (6) Methods of behavioral analysis in an animal model translate to dissection of compulsive rituals in OCD patients, leading to diagnostic tests.

Cultural Transmission of Precautionary Ideas: The Weighted Role of Implicit Motivation

Inspired by the idea that cognitive systems evoke cultural phenomena, this study tested a theory suggesting precautionary cognitive mechanisms as both a constraint and an enabler of transmission of cultural concepts such as religious rituals. Using ‘restricted range of themes’ as a link between precautionary cognition and religious rituals, this cross cultural study of Zulu communities in sa tested people’s inferences about implications of failure to perform life-stage rituals in order to identify the nature of the presence of precautionary themes in Zulu rituals and any involvement of environmental factors. The results reflected inferences rather than echoing of formal descriptions of rituals, and revealed a consistent affinity between certain threat-domains and specific Zulu rituals: birth and early age rituals evoked the Contamination/Contagion domain, women’s maturity rituals evoked the Decline in Resources domain, marital rituals evoked a mixture of Decline in Resources and Loss of Status domains, and death rituals evoked the Predation/Assault domain. This suggests that precautionary cognition effect on religious rituals is mediated by life-history strategy rather than by ecology factors, and also, that understanding precautionary cognition is crucial for uncovering the real motivations for religious behaviour, as direct reports cannot be taken at face value.

Validity of Quinpirole Sensitization Rat Model of OCD: Linking Evidence from Animal and Clinical Studies

Obsessive-compulsive disorder (OCD) is a neuropsychiatric disorder with 1–3% prevalence. OCD is characterized by recurrent thoughts (obsessions) and repetitive behaviors (compulsions). The pathophysiology of OCD remains unclear, stressing the importance of pre-clinical studies. The aim of this article is to critically review a proposed animal model of OCD that is characterized by the induction of compulsive checking and behavioral sensitization to the D2/D3 dopamine agonist quinpirole. Changes in this model have been reported at the level of brain structures, neurotransmitter systems and other neurophysiological aspects. In this review, we consider these alterations in relation to the clinical manifestations in OCD, with the aim to discuss and evaluate axes of validity of this model. Our analysis shows that some axes of validity of quinpirole sensitization model (QSM) are strongly supported by clinical findings, such as behavioral phenomenology or roles of brain structures. Evidence on predictive validity is contradictory and ambiguous. It is concluded that this model is useful in the context of searching for the underlying pathophysiological basis of the disorder because of the relatively strong biological similarities with OCD.

A quantitative measure of restricted and repetitive behaviors for early childhood

Background

Restricted and repetitive behaviors are characteristic phenotypic features of many neurodevelopmental, psychiatric, and neurological conditions. During early childhood, such behaviors are considered normative. More research is needed to delineate the dimensions of restricted and repetitive behavior across typical and atypical development during this period.

Methods

We developed the 34-item parent-rated Repetitive Behavior Scale for Early Childhood (RBS-EC) to capture quantitative, dimensional features across a broad range of behaviors contributing to this domain. We evaluated its psychometric properties and factor structure in a community sample of 914 toddlers.

Results

The RBS-EC showed excellent overall internal consistency (α = 0.90), strong test-retest reliability (ICC = 0.87 for topographies and 0.90 for frequency) and evidence of convergent and discriminative validity. Using a split-half approach to factor analysis, we identified that a three- or four-factor structure best fit the data and confirmatory factor analysis indicated acceptable fit for both models. The empirically derived four-factor model was consistent with our conceptual model and included repetitive motor, restricted interests and behavior, ritual and routine, and self-directed behavior.

Conclusions

This initial study indicates that the RBS-EC is a reliable and valid instrument for characterizing quantitative, dimensional aspects of restricted and repetitive behaviors in young children.

Electronic supplementary material

The online version of this article (doi:10.1186/s11689-016-9161-x) contains supplementary material, which is available to authorized users.

Human compulsivity: A perspective from evolutionary medicine

Biological explanations address not only proximal mechanisms (for example, the underlying neurobiology of obsessive-compulsive disorder), but also distal mechanisms (that is, a consideration of how particular neurobiological mechanisms evolved). Evolutionary medicine has emphasized a series of explanations for vulnerability to disease, including constraints, mismatch, and tradeoffs. The current paper will consider compulsive symptoms in obsessive-compulsive and related disorders and behavioral addictions from this evolutionary perspective. It will argue that while obsessive-compulsive disorder (OCD) is typically best conceptualized as a dysfunction, it is theoretically and clinically valuable to understand some symptoms of obsessive-compulsive and related disorders in terms of useful defenses. The symptoms of behavioral addictions can also be conceptualized in evolutionary terms (for example, mismatch), which in turn provides a sound foundation for approaching assessment and intervention.

Activation of D2 autoreceptors alters cocaine-induced locomotion and slows down local field oscillations in the rat ventral tegmental area

Psychoactive substances affecting the dopaminergic system induce locomotor activation and, in high doses, stereotypies. Network mechanisms underlying the shift from an active goal-directed behavior to a "seemingly purposeless" stereotypic locomotion remain unclear. In the present study we sought to determine the relationships between the behavioral effects of dopaminergic drugs and their effects on local field potentials (LFPs), which were telemetrically recorded within the ventral tegmental area (VTA) of freely moving rats. We used the D2/D3 agonist quinpirole in a low, autoreceptor-selective (0.1 mg/kg, i.p.) and in a high (0.5 mg/kg, i.p.) dose, and a moderate dose of cocaine (10 mg/kg, i.p.). In the control group, power spectrum analysis revealed a prominent peak of LFP power in the theta frequency range during active exploration. Cocaine alone stimulated locomotion, but had no significant effect on the peak of the LFP power. In contrast, co-administration of low dose quinpirole with cocaine markedly altered the pattern of locomotion, from goal-directed exploratory behavior to recurrent motion resembling locomotor stereotypy. This behavioral effect was accompanied by a shift of the dominant theta power toward a significantly lower (by ∼15%) frequency. High dose quinpirole also provoked an increased locomotor activity with signs of behavioral stereotypies, and also induced a shift of the dominant oscillation frequency toward the lower range. These results demonstrate a correlation between the LFP oscillation frequency within the VTA and a qualitative aspect of locomotor behavior, perhaps due to a variable level of coherence of this region with its input or output areas.

Chimpanzee accumulative stone throwing

The study of the archaeological remains of fossil hominins must rely on reconstructions to elucidate the behaviour that may have resulted in particular stone tools and their accumulation. Comparatively, stone tool use among living primates has illuminated behaviours that are also amenable to archaeological examination, permitting direct observations of the behaviour leading to artefacts and their assemblages to be incorporated. Here, we describe newly discovered stone tool-use behaviour and stone accumulation sites in wild chimpanzees reminiscent of human cairns. In addition to data from 17 mid- to long-term chimpanzee research sites, we sampled a further 34 Pan troglodytes communities. We found four populations in West Africa where chimpanzees habitually bang and throw rocks against trees, or toss them into tree cavities, resulting in conspicuous stone accumulations at these sites. This represents the first record of repeated observations of individual chimpanzees exhibiting stone tool use for a purpose other than extractive foraging at what appear to be targeted trees. The ritualized behavioural display and collection of artefacts at particular locations observed in chimpanzee accumulative stone throwing may have implications for the inferences that can be drawn from archaeological stone assemblages and the origins of ritual sites.

Effects of Anxiety on Spontaneous Ritualized Behavior

Environmental uncertainty and uncontrollability cause psycho-physiological distress to organisms, often impeding normal functioning. A common response involves ritualization, that is, the limitation of behavioral expressions to predictable stereotypic and repetitive motor patterns. In humans, such behaviors are also symptomatic of psychopathologies like obsessive-compulsive disorder (OCD) and autism spectrum disorders (ASDs). Although these reactions might be mediated by different neural pathways, they serve to regain a sense of control over an uncertain situation by engaging in behavioral patterns characterized by redundancy (superfluous actions that exceed the functional requirements of a goal), repetitiveness (recurrent behaviors or utterances), and rigidity (emphasis on fidelity and invariance). We examined whether ritualized behavior will manifest spontaneously as a dominant behavioral strategy in anxiogenic situations. Manipulating anxiety, we used motion-capture technology to quantify various characteristics of hand movements. We found that induced anxiety led to an increase in repetitiveness and rigidity, but not redundancy. However, examination of both psychological and physiological pathways revealed that repetitiveness and rigidity were predicted by an increase in heart rate, while self-perceived anxiety was a marginally significant predictor of redundancy. We suggest that these findings are in accordance with an entropy model of uncertainty, in which anxiety motivates organisms to return to familiar low-entropy states in order to regain a sense of control. Our results might inform a better understanding of ritual behavior and psychiatric disorders whose symptoms include over-ritualization.

Applications of the Neonatal Quinpirole Model to Psychosis and Convergence upon the Dopamine D2 Receptor

This mini review focuses on the importance of the dopamine D₂-like receptor family and its importance in psychosis. Past findings from this laboratory along with collaborators have been that neonatal quinpirole (a dopamine D₂-like receptor agonist) results in increases in dopamine D₂ receptor sensitivity that persists throughout the animal's lifetime. Findings from this model have been shown to have particular application and validity to schizophrenia, but may have broader implications toward other psychoses, which is reviewed in the present manuscript. In the present review, we also highlight other models of psychoses that have been centered on the subchronic administration of quinpirole to rats in order to model certain psychoses, which has uncovered some interesting and valid behavioral findings. This review highlights the importance of the combination of behavioral findings and neurobiological mechanisms focusing on neural plasticity in discovering underlying pathologies in these disorders that may lead to treatment discoveries, as well as the value of animal models across all psychoses.

Animal models of obsessive-compulsive disorder: utility and limitations

Obsessive-compulsive disorder (OCD) is a disabling and common neuropsychiatric condition of poorly known etiology. Many attempts have been made in the last few years to develop animal models of OCD with the aim of clarifying the genetic, neurochemical, and neuroanatomical basis of the disorder, as well as of developing novel pharmacological and neurosurgical treatments that may help to improve the prognosis of the illness. The latter goal is particularly important given that around 40% of patients with OCD do not respond to currently available therapies. This article summarizes strengths and limitations of the leading animal models of OCD including genetic, pharmacologically induced, behavioral manipulation-based, and neurodevelopmental models according to their face, construct, and predictive validity. On the basis of this evaluation, we discuss that currently labeled "animal models of OCD" should be regarded not as models of OCD but, rather, as animal models of different psychopathological processes, such as compulsivity, stereotypy, or perseverance, that are present not only in OCD but also in other psychiatric or neurological disorders. Animal models might constitute a challenging approach to study the neural and genetic mechanism of these phenomena from a trans-diagnostic perspective. Animal models are also of particular interest as tools for developing new therapeutic options for OCD, with the greatest convergence focusing on the glutamatergic system, the role of ovarian and related hormones, and the exploration of new potential targets for deep brain stimulation. Finally, future research on neurocognitive deficits associated with OCD through the use of analogous animal tasks could also provide a genuine opportunity to disentangle the complex etiology of the disorder.

Anxiety, hyperactivity and stereotypy in a zebrafish model of fragile X syndrome and autism spectrum disorder

Fragile X syndrome (FXS) is the most common form of inherited intellectual disability and is caused by a loss of function of the fragile X mental retardation (fmr1) gene. Animal fmr1-knockout (KO) models are not only of interest for the study of FXS, but have also important implications for our understanding of autism spectrum disorder (ASD). Here we report the behavioral changes in fmr1-knockout zebrafish in an open field with two white and two transparent walls. The neophobic responses that in wild-type (WT) zebrafish normally occur during the first 5-10 min in an unfamiliar environment (such as freezing, hypo-activity and preferences for the bottom and opaque walls of the tank), were weakened in fmr1 mutants, suggesting a reduction of novelty-induced anxiety. The fmr1-KO zebrafish showed somewhat increased vertical activity beyond the 'neophobic phase', but no overall hyperactivity. The mutants demonstrated a clear habituation-independent preference for the transparent walls. Whether this was attributable to altered spatial information processing or to reduced avoidance of open spaces is discussed. Finally, since restrictive repetitive (or stereotypical) behaviors are frequently present in FXS and ASD patients, we analyzed relative turning angles, directional and preferential turning ratios and performed frequency-domain analysis. However, no indications of abnormal movement patterning were detected. The possible reasons for the absence of stereotypical behaviors are discussed in terms of behavioral endpoint selection and of eliciting conditions. Overall, our findings are consistent with those reported in fmr1-KO mice and suggest that further analysis of the fmr1-KO zebrafish model has potential to deepen our understanding of FXS and ASD.

Rapid animal welfare assessment: an archaeological approach

The welfare of an individual depends on its capacity to overcome suboptimal conditions in its environment; otherwise, its physical and psychological health becomes compromised. A situation that clearly indicates lack of control of the environment is the expression of abnormal behaviours, such as stereotypies. This study aimed to verify the well-being of police horses using a new rapid form of welfare assessment: an archaeological approach. To this end, we sampled and quantified marks found on the stables, deposited as a result of abnormal behaviour. We cross-referenced these physical marks with veterinary records of diseases, such as colic, known to be associated with stress. A total of 46 horses were sampled and the results showed a significant medium-strength, positive correlation between bite mark frequency on stable doors and the incidence of colic. A weak significant positive correlation was found between length of scratch marks (from pawing) and the incidence of lameness. We conclude that these marks reflect the accumulated expression of abnormal behaviour and can provide rapid insight into the welfare of individual animals.

Adaptive and maladaptive correlates of repetitive behavior and restricted interests in persons with down syndrome and developmentally-matched typical children: a two-year longitudinal sequential design

We examined the course of repetitive behavior and restricted interests (RBRI) in children with and without Down syndrome (DS) over a two-year time period. Forty-two typically-developing children and 43 persons with DS represented two mental age (MA) levels: "younger" 2-4 years; "older" 5-11 years. For typically developing younger children some aspects of RBRI increased from Time 1 to Time 2. In older children, these aspects remained stable or decreased over the two-year period. For participants with DS, RBRI remained stable or increased over time. Time 1 RBRI predicted Time 2 adaptive behavior (measured by the Vineland Scales) in typically developing children, whereas for participants with DS, Time 1 RBRI predicted poor adaptive outcome (Child Behavior Checklist) at Time 2. The results add to the body of literature examining the adaptive and maladaptive nature of repetitive behavior.

Too good to be true: rhesus monkeys react negatively to better-than-expected offers

To succeed in a dynamically changing world, animals need to predict their environments. Humans, in fact, exhibit such a strong desire for consistency that one of the most well-established findings in social psychology is the effort people make to maintain consistency among their beliefs, attitudes, and behavior. However, displeasure with unpredictability leads to a potential paradox, because a positive outcome that exceeds one's expectations often leads to increased subjective value and positive affect, not the opposite. We tested the hypothesis that two evolutionarily-conserved evaluation processes underlie goal-directed behavior: (1) consistency, concerned with prediction errors, and (2) valuation, concerned with outcome utility. Rhesus monkeys (Macaca mulatta) viewed a food item and then were offered an identical, better, or worse food, which they could accept or reject. The monkeys ultimately accepted all offers, attesting to the influence of the valuation process. However, they were slower to accept the unexpected offers, and they exhibited aversive reactions, especially to the better-than-expected offers, repeatedly turning their heads and looking away before accepting the food item. Our findings (a) provide evidence for two separable evaluation processes in primates, consistency and value assessment, (b) reveal a direct relationship between consistency assessment and emotional processes, and (c) show that our wariness with events that are much better than expected is shared with other social primates.

Outlining new frontiers for the comprehension of obsessive-compulsive disorder: a review of its relationship with fear and anxiety

Anxiety is an important component of the psychopathology of the obsessive-compulsive disorder (OCD). So far, most interventions that have proven to be effective for treating OCD are similar to those developed for other anxiety disorders. However, neurobiological studies of OCD came to conclusions that are not always compatible with those previously associated with other anxiety disorders.

OBJECTIVES

The aim of this study is to review the degree of overlap between OCD and other anxiety disorders phenomenology and pathophysiology to support the rationale that guides research in this field.

RESULTS

Clues about the neurocircuits involved in the manifestation of anxiety disorders have been obtained through the study of animal anxiety models, and structural and functional neuroimaging in humans. These investigations suggest that in OCD, in addition to dysfunction in cortico-striatal pathways, the functioning of an alternative neurocircuitry, which involves amygdalo-cortical interactions and participates in fear conditioning and extinction processes, may be impaired.

CONCLUSION

It is likely that anxiety is a relevant dimension of OCD that impacts on other features of this disorder. Therefore, future studies may benefit from the investigation of the expression of fear and anxiety by OCD patients according to their type of obsessions and compulsions, age of OCD onset, comorbidities, and patterns of treatment response.

Environmentally enriched rearing environments reduce repetitive perseveration in caged mink, but increase spontaneous alternation

Studies spanning 15 species (including American mink, Neovison vison) demonstrate that within similarly-housed populations, individuals displaying high levels of stereotypic behaviour (SB) typically show perseverative responding (e.g. during set-shifting, or reversal/extinction learning). Similar correlations in autism and schizophrenia suggest this indicates captivity-induced cortico-striatal circuit dysfunction. However, this pattern does not prove developmental impairment: SB, perseveration and their inter-correlations also occur in normal humans. We therefore differentially-reared enriched versus non-enriched mink to investigate whether treatments that exacerbate SB correspondingly increase perseveration (Study 1). Enriched-rearing did reduce SB and perseverative response repetition (in two-choice guessing tasks), while increasing spontaneous alternation: a strategy yielding more rewards, and suggesting enhanced hippocampal development. This complements previous research demonstrating cortical/hippocampal impairments and reduced behavioural flexibility in non-enriched animals, with implications for research animals and wild animals captive-raised for reintroduction into nature. Consistent with previous data, highly stereotypic subjects repeated guessing task responses most rapidly, suggesting disinhibition during repetition. However, unexpectedly, SB and perseveration did not co-vary across individuals. We therefore suggest that behavioural changes manifest as increased perseveration are important but do not fully explain captive animals' SBs, possible reasons including the contributory role of differential motivations for underlying source behaviours. Re-analyses of old data (Study 2) confirmed that spontaneous alternation is profitable; and demonstrated that the precise methods used for quantifying perseveration and SB can modify the strength of apparent relationships between them, as can statistically controlling for feeding motivation: as predicted, partialling out motivational effects increased the variance in SB predicted by perseveration.