Owner reports of attention, activity, and impulsivity in dogs: a replication study

New Advances in Attention-Deficit/Hyperactivity Disorder-like Dogs

Similar to humans, dogs could suffer an Attention-Deficit/Hyperactivity Disorder-like syndrome (ADHD-like). In fact, several studies highlight the use of dogs as a model for studying ADHD. This condition entails behavioral problems expressed through impulsivity, attention issues, hyperactivity, and/or aggression, compromising the quality of life for both the caregiver and the dog. The pathophysiology of ADHD-like is complex and is associated with dysregulation of various neurotransmitters such as serotonin and dopamine. The expression of ADHD-like behavior in dogs would appear to depend on a classical gene-environment interaction as is the case with many neurological disorders in humans. In addition to the described symptomatology, ADHD-like dogs can exhibit strong comorbidities with compulsive behaviors, aggressiveness, inappropriate elimination and fearfulness, in addition to epilepsy, foreign body ingestion, and pruritus. In spite of the fact that there is no veterinary consensus about the diagnosis of ADHD-like, some validated questionnaires could be helpful, but these cannot be used as a unique diagnostic tool. The use of drugs, such as fluoxetine, in addition to an adequate environmental enrichment, relaxation protocols, and behavior modification can achieve an adequate quality of life for both the dog and caregivers.

Towards an Objective Measurement Tool for ADHD-like Traits in Family Dogs: A Comprehensive Test Battery

Family dogs exhibit neuropsychological deficits similar to attention-deficit/hyperactivity disorder (ADHD) symptoms in humans. Questionnaire methods have mostly been used to assess ADHD-like behaviours in dogs. In addition to our validated questionnaire (Dog ADHD and Functionality Rating Scale-DAFRS; 2024), we developed a simple behavioural test battery covering the ADHD symptom domains (i.e., inattention, hyperactivity, and impulsivity) in dogs. Our main aim was (i) to provide a final external validation step to the DAFRS by examining its associations with the test variables (N = 59); and (ii) to compare owner- and trainer-rated factor scores' associations with the test variables (n = 38). We developed four tests covering the ADHD symptom domains: the attention test (inattention), the plush dog test (impulsivity), the leash test, and the sit test (hyperactivity). All four behavioural variables correlated with their respective questionnaire scores, i.e., the strongest for hyperactivity, and the least strong for inattention. Both owner- and trainer-rated scores (n = 38) correlated with the relevant test variables in an expected direction. Dogs' training status was linked only to the sit test results. Test-retest analyses (n = 34) indicated moderate-to-excellent agreement across all behavioural variables. Our findings support the validity of our novel human-analogue questionnaire for dogs as the behavioural tests strongly correlate with the relevant questionnaire scores, indicating that the two constructs together can effectively assess inattention, hyperactivity, and impulsivity in dogs.

EEG decoding for effects of visual joint attention training on ASD patients with interpretable and lightweight convolutional neural network

Visual joint attention, the ability to track gaze and recognize intent, plays a key role in the development of social and language skills in health humans, which is performed abnormally hard in autism spectrum disorder (ASD). The traditional convolutional neural network, EEGnet, is an effective model for decoding technology, but few studies have utilized this model to address attentional training in ASD patients. In this study, EEGNet was used to decode the P300 signal elicited by training and the saliency map method was used to visualize the cognitive properties of ASD patients during visual attention. The results showed that in the spatial distribution, the parietal lobe was the main region of classification contribution, especially for Pz electrode. In the temporal information, the time period from 300 to 500 ms produced the greatest contribution to the electroencephalogram (EEG) classification, especially around 300 ms. After training for ASD patients, the gradient contribution was significantly enhanced at 300 ms, which was effective only in social scenarios. Meanwhile, with the increase of joint attention training, the P300 latency of ASD patients gradually shifted forward in social scenarios, but this phenomenon was not obvious in non-social scenarios. Our results indicated that joint attention training could improve the cognitive ability and responsiveness of social characteristics in ASD patients.

Improving the performance of P300-based BCIs by mitigating the effects of stimuli-related evoked potentials through regularized spatial filtering

Objective.the P300-based brain-computer interface (BCI) establishes a communication channel between the mind and a computer by translating brain signals into commands. These systems typically employ a visual oddball paradigm, where different objects (linked to specific commands) are randomly and frequently intensified. Upon observing the target object, users experience an elicitation of a P300 event-related potential in their electroencephalography (EEG). However, detecting the P300 signal can be challenging due to its very low signal-to-noise ratio (SNR), often compromised by the sequence of visual evoked potentials (VEPs) generated in the occipital regions of the brain in response to periodic visual stimuli. While various approaches have been explored to enhance the SNR of P300 signals, the impact of VEPs has been largely overlooked. The main objective of this study is to investigate how VEPs impact P300-based BCIs. Subsequently, the study aims to propose a method for EEG spatial filtering to alleviate the effect of VEPs and enhance the overall performance of these BCIs.Approach.our approach entails analyzing recorded EEG signals from visual P300-based BCIs through temporal, spectral, and spatial analysis techniques to identify the impact of VEPs. Subsequently, we introduce a regularized version of the xDAWN algorithm, a well-established spatial filter known for enhancing single-trial P300s. This aims to simultaneously enhance P300 signals and suppress VEPs, contributing to an improved overall signal quality.Main results.analyzing EEG signals shows that VEPs can significantly contaminate P300 signals, resulting in a decrease in the overall performance of P300-based BCIs. However, our proposed method for simultaneous enhancement of P300 and suppression of VEPs demonstrates improved performance in P300-based BCIs. This improvement is verified through several experiments conducted with real P300 data.Significance.this study focuses on the effects of VEPs on the performance of P300-based BCIs, a problem that has not been adequately addressed in previous studies. It opens up a new path for investigating these BCIs. Moreover, the proposed spatial filtering technique has the potential to further enhance the performance of these systems.

Epilepsy is more than a simple seizure disorder: Parallels between human and canine cognitive and behavioural comorbidities

Psychiatric and cognitive comorbidities have been known to play a major role in human epilepsy for a long time. People with epilepsy (PWE) frequently express signs of varying psychiatric and cognitive disorders affecting their quality and quantity of life (QoL/QaoL). Over the last few years, research on behavioural comorbidities and their effect on the underlying disease have been performed in canine epilepsy. The following article reviews manifestations of comorbidities in canine epilepsy with an emphasis on patterns of clinical signs and their effects on QoL and QaoL. Cognitive and behavioural alterations in epileptic dogs are mainly represented by fear-/anxiety related behaviour and cognitive impairment (CI). Reduced trainability and altered reactions to daily situations are common results of comorbid changes posing obstacles in everyday life of owners and their dog. In addition, clinical signs similar to attention deficit hyperactivity disorder (ADHD) in humans have been reported. Canine attention-deficit-hyperactivity-disorder-like (c-ADHD-like) behaviour should, however, be evaluated critically, as there are no official criteria for diagnosis of ADHD or ADHD-like behaviour in dogs, and some of the reported signs of c-ADHD-like behaviour could be confused with anxiety-associated behaviour. Many intrinsic and extrinsic factors could potentially influence the development of behavioural and cognitive comorbidities in canine epilepsy. In particular, seizure frequency/severity, signalment and factors concerning disease management, such as pharmacotherapy and nutrition, are closely linked with the presence of the aforementioned comorbid disorders. Further studies of behavioural alterations in epileptic dogs are needed to comprehend the complexity of clinical signs and their multifactorial origin.

Development of a human-analogue, 3-symptom domain Dog ADHD and Functionality Rating Scale (DAFRS)

The family dog, in its natural environment, exhibits neuropsychological deficits redolent of human psychiatric disorders, including behaviours that are similar to human attention-deficit/hyperactivity disorder (ADHD) symptoms. Based on standard questionnaire methods in humans, we aimed to develop and validate a detailed, psychometrically improved tool to assess owner views on relevant dog behaviours. We modified available questionnaires by adding items that allow for separate analysis of impulsivity, and items on functional impairment. We collected data from 1168 owners for different validation steps of the new questionnaire and, similarly to assessment of humans where teachers also evaluate as an expert control, we collected data from dog trainers. Exploratory and confirmatory factor analysis revealed 3 factors: inattention (IA), hyperactivity (H) and impulsivity (I), corresponding to all three human symptom dimensions in dogs. Test-retest analyses showed excellent agreement between measurements for all factors. Similarly to findings with humans, trainer-owner rating comparisons showed fair (IA) to moderate (H, I) agreement. As in humans, greater ADHD scores were associated with greater functional impairment scores. We suggest that in dogs, similarly to humans, parallel examination of (extreme) ADHD and functional impairment scores could help distinguish diagnosable individuals, after further validation of the questionnaire using a relevant behaviour test.

Imperceptible body transformation in virtual reality: Saliency of self representation

Change blindness (CB) is the perceptual phenomenon whereby people are blind to dramatic changes in their visual environment. In virtual reality (VR) a person's body can be substituted by a life-sized virtual one that moves synchronously with their real body movements as their self-representation. We consider whether CB occurs in VR, and whether there are differences in the case of changes to their own virtual body compared with the body of another. Forty people took part in a Qi Gong lesson in VR led by a virtual instructor. During the lesson both their own and the instructor's face dramatically changed in appearance. Overall, 73% and 85% did not notice the changes to their own and instructor's face respectively. People make iconic inferences about their visual surroundings without sampling detail, and reduced CB in the case of their own body may be a marker for self-representation.

Auditory white noise exposure results in intrinsic cortical excitability changes

Cortical excitability is commonly measured by applying magnetic stimulation in combination with measuring behavioral response. This measure has, however, some shortcomings including spatial limitation to the primary motor cortex and not accounting for intrinsic excitability fluctuations. Here, we use a measure for intrinsic excitability based on phase synchronization previously validated for epilepsy. We apply this measure in 30 healthy participants' magnetoencephalography (MEG) recordings during the exposure of auditory white noise, a stimulus that has been suggested to modify cortical excitability. Using cortical parcellation of the MEG source data, we could find a specific pattern of increased and decreased excitability while participants are exposed to white noise vs. silence. Specifically, excitability during white noise exposure decreases in the frontal lobe and increases in the temporal lobe. This study thus adds to the understanding of cortical excitability changes due to specific environmental stimuli as well as the spatial extent of these effects.

Breed, age, and social environment are associated with personality traits in dogs

Personality in pets and other domesticated animals is important for their well-being and it can also influence human-animal relationships. Genetic and environmental factors influencing unwanted behavior in dogs are somewhat well known, but the factors influencing dog personality remain understudied. Here we examined environmental and demographic factors associated with seven broad personality traits in a survey of over 11,000 dogs. We utilized linear models and extensive model validation to examine the factors that have the most significant influences on personality and calculated effect sizes to assess the importance of these variables. Breed and age had the strongest associations with dog personality traits. Some environmental factors, especially puppyhood socialization, were also associated with personality. All factors had small effect sizes, highlighting that a lot of variation in personality remains unexplained. Our results indicate that personality traits are complex and strikingly similar in dogs, humans, and other nonhuman animals.

Serotonin and Dopamine Blood Levels in ADHD-Like Dogs

As with humans, dogs can suffer from attention deficit hyperactivity disorder-like (ADHD-like) behaviors naturally and exhibit high levels of hyperactivity/impulsivity and attention deficit problems, making the domestic dog a potential animal model for ADHD. ADHD has a very complex pathophysiology in which many neurotransmitters are involved, such as serotonin and dopamine. The aim of the study was to evaluate serum serotonin and dopamine levels in dogs with ADHD-like symptomatology. Fifty-eight dogs were studied, of which, thirty-six were classified as ADHD-like after physical and behavioral assessments. Additionally, the dogs’ owners performed a series of scientifically validated questionnaires which included C-BARQ, the Dog Impulsivity Assessment Scale, and the Dog-ADHD rating scale. Serum from every animal was collected after the behavioral assessments and analyzed with commercial ELISA tests for serotonin and dopamine determination. Kruskal–Wallis tests and Lasso regressions were applied to assess the relationships between both neurotransmitters and the ADHD-like behaviors (as assessed by clinical evaluation and through the different questionnaires). The dogs clinically classified as ADHD-like showed lower serotonin and dopamine concentrations. Further, serotonin and dopamine levels were also linked to aggression, hyperactivity, and impulsivity. Decreased serotonin concentrations were also related to fear, attachment, and touch sensitivity. Finally, it must be noted that our data suggested a strong relationship between serotonin and dopamine and ADHD-like behaviors.

To what extent is dot comparison an appropriate measure of approximate number system?

Introduction

Number sense has been systematically measured using dot comparison tasks. However, recent studies have reported that performance on dot comparison might be influenced inhibitory control and visual properties of dot arrays. In the present study, we analysed the influence of continuous magnitude, inhibitory control, and numerical ratio on the dot comparison performance of preschool children.

Methods

Participants were 517 preschool children from 13 different schools in Chile. Children completed a dot comparison and two inhibitory control tasks. Gebuis and Reynvoet method was used to create well-controlled dot arrays for use in the dot comparison task. A logistic mixed effects model was conducted to predict participants' dot comparison accuracy. Continuous magnitude and ratio were entered as level-1 predictors and inhibitory control as level-2 predictors.

Results

The results showed that all predictors made a significant contribution to dot comparison accuracy. Furthermore, a significant double interaction (inhibitory control x continuous magnitude) and a triple interaction (inhibitory control x continuous magnitude x ratio) showed that the contribution of inhibitory control skills in dot comparison accuracy depends on the continuous properties of dot arrays and ratio.

Discussion

These findings suggest that preschool children rely more on continuous magnitudes than numerosity in dot comparison tasks. They also indicate that the greater children's inhibitory control, the more able they are to respond based on numerosity in fully incongruent trials, particularly when ratio is low (easiest items). Taken together, the above findings support the competing processes account provided that both ANS and inhibitory control skills influence performance on dot comparison tasks.

The Variation of Serotonin Values in Dogs in Different Environmental Conditions

Simple Summary

The multiple implications of serotonin in behavior manifestations have shaped the goal of the present study, which was to evaluate the variation of serum serotonin levels in different experimental groups of dogs to establish whether serum serotonin levels could serve as indicators of aggressive behavior, especially when adoption is considered. The experimental groups were divided into three variants: Variant 1—two groups of medium (n = 6) and small (n = 4) breed shelter dogs; Variant 2—dogs with owners (n = 15) and dogs without owners but in foster care (n = 10), after administration of pre-spaying/neutering anesthesia; and Variant 3—dogs in different behavioral states (n = 8), classified as follows: M1—happy, M2—aggressive, M3—calmed status, post-exposure to a stressful situation, compared to the reference time referred to as M0. Significant results were found between M1 and M2 (p ≤ 0.05, decrease of serotonin by 89.61 ng/mL), as well as between M2 and M3 (p ≤ 0.008, increase by 112.78 ng/mL). Following anesthesia, the average mean serotonin values were significantly lower (p ≤ 0.003), by 63.85 ng/mL, in stray dogs compared to dogs with owners, leading to a presumptive conclusion that serotonin levels could serve as indicators for potentially aggressive behaviors.

Abstract

Serotonin is considered to be the neurotransmitter that controls several types of behavior: aggressiveness, impulsivity, food selection, stimulation, sexual behavior, reaction to pain, and emotional manifestations. The aim of this study was to determine the serotonin values in 43 dogs, divided into three different experimental variants: (1) between two groups of medium (n = 6) and small (n = 4) breed shelter dogs; (2) in dogs with (n = 15) and without (n = 10) owners after administration of pre-spaying/neutering anesthesia; (3) in different behavioral states (n = 8) classified as follows: M1—happy, M2—aggressive, M3—calmed status, post-exposure to a stressful situation, compared to the reference time referred to as M0. There were no significant differences (p ≥ 0.05) regarding the serotonin values between the two groups of medium and small breed shelter dogs. Following anesthesia, the average mean serotonin values were significantly lower (p ≤ 0.003), by 63.85 ng/mL, in stray dogs compared to dogs with owners. No significant differences (p ≥ 0.05) were found when comparing the reference time M0 to M1, M2, and M3. The differences decreased significantly (p ≤ 0.05), by 89.61 ng/mL, between M1 and M2 and increased significantly (p ≤ 0.008), by 112.78 ng/mL, between M2 and M3.

Impact of Different Genres of Background Music on a Memory Test

Abstract. Many studies have examined the effects of different types of background music on cognitive abilities. However, the results of these studies range from finding music to be a significant distraction to finding it to be beneficial. This study examined the effects of different music genres and silence on a memory test. One hundred participants were randomly assigned to four different groups: silence (no music), classical music, rock, and the final group could choose any genre they liked. The California Verbal Learning Test – Second Edition (CVLT-II) was administered to assess participant’s memory. Anxiety was also assessed before and after the memory test to see whether the music had any effect. Generally, results suggested that music presence or genre had little tangible effect on memory or anxiety.

Evaluating ADHD Assessment for Dogs: A Replication Study

The family dog, in its natural environment, exhibits neuropsychological deficits redolent of human psychiatric disorders, including behaviours similar to human Attention-Deficit/Hyperactivity Disorder (ADHD) symptoms. For dogs, Vas and colleagues developed a 13-item questionnaire to measure inattention and hyperactivity/impulsivity (Dog ARS; 2007). We re-assessed, in a large sample of dogs (N = 319), psychometric properties of the Dog ARS, to identify possible limitations as a basis for further development. We examined the cross-study stability of factor structure and 40-day temporal stability of item and subscale scores and compared owner-report with expert (dog trainer)-report (n = 86), paralleling human parent/teacher assessments. To identify ambiguous items, we administered a modified version (including “I don’t know” options, N = 520) to a different sample. We could replicate the factor structure with evidence of good internal consistency and test–retest reliability of both subscales. Agreement between owner and trainer ratings was fair (inattention) and moderate (hyperactivity/impulsivity). Three ambiguous items were identified. Overall, we claim that the Dog ARS is a reliable tool to assess ADHD-like behaviour in dogs, but in its current form, it is not suitable to detect diagnosable individuals, as it does not comprise items assessing functional impairment, and also, the inclusion of owner-expert ratings in the evaluation process would be necessary.

Personality traits associate with behavioral problems in pet dogs

Personality traits, especially neuroticism, strongly predict psychopathology. The domestic dog (Canis lupus familiaris Linnaeus, 1758) is used as a natural model for psychiatric disorders, but the similarity between dog and human personality and the association between dog personality and unwanted behavioral traits, such as fearfulness, aggressiveness, and impulsivity/inattention, remain unknown. This study utilized structural equation modeling (SEM) with survey data of 11,360 dogs to examine the associations and correlations between seven personality and ten unwanted behavioral traits. Personality traits included insecurity, energy, training focus, aggressiveness/dominance, human sociability, dog sociability, and perseverance. Unwanted behavioral traits included fearfulness, noise sensitivity, fear of surfaces/heights, separation anxiety, barking, stranger-directed aggression, owner-directed aggression, dog-directed aggression, hyperactivity/impulsivity, and inattention. We first fitted confirmatory factor models for the unwanted behavioral traits and the best model grouped unwanted behaviors into four latent traits: fear-related behavior, fear-aggression, aggression, and impulsivity/inattention and used this structure in the subsequent SEM model. Especially, insecurity, which resembles the human neuroticism trait, was strongly associated with unwanted behavior, paralleling the association between neuroticism and psychopathology. Similarly, training focus, resembling conscientiousness, was negatively related to impulsivity/inattention, and aggressiveness/dominance was associated with aggressive behaviors, resembling associations of conscientiousness and agreeableness with attention deficit hyperactivity disorder and aggression-related psychopathology, respectively. These results indicate that dog personality traits resemble human personality traits, suggesting that their neurological and genetic basis may also be similar and making the dog a suitable animal model for human behavior and psychiatric disorders.

Canine hyperactivity, impulsivity, and inattention share similar demographic risk factors and behavioural comorbidities with human ADHD

Attention-deficit hyperactivity disorder (ADHD) is a prevalent neurodevelopmental disorder impairing the quality of life of the affected individuals. The domestic dog can spontaneously manifest high hyperactivity/impulsivity and inattention which are components of human ADHD. Therefore, a better understanding of demographic, environmental and behavioural factors influencing canine hyperactivity/impulsivity and inattention could benefit both humans and dogs. We collected comprehensive behavioural survey data from over 11,000 Finnish pet dogs and quantified their level of hyperactivity/impulsivity and inattention. We performed generalised linear model analyses to identify factors associated with these behavioural traits. Our results indicated that high levels of hyperactivity/impulsivity and inattention were more common in dogs that are young, male and spend more time alone at home. Additionally, we showed several breed differences suggesting a substantial genetic basis for these traits. Furthermore, hyperactivity/impulsivity and inattention had strong comorbidities with compulsive behaviour, aggressiveness and fearfulness. Multiple of these associations have also been identified in humans, strengthening the role of the dog as an animal model for ADHD.

Objective Video-Based Assessment of ADHD-Like Canine Behavior Using Machine Learning

Simple Summary

This paper applies machine learning techniques to propose an objective video-based method for assessing the degree of canine ADHD-like behavior in veterinary consultation room. The method is evaluated using clinical data of dog patients in a veterinary clinic, as well as in a focus group of experts.

Abstract

Canine ADHD-like behavior is a behavioral problem that often compromises dogs’ well-being, as well as the quality of life of their owners; early diagnosis and clinical intervention are often critical for successful treatment, which usually involves medication and/or behavioral modification. Diagnosis mainly relies on owner reports and some assessment scales, which are subject to subjectivity. This study is the first to propose an objective method for automated assessment of ADHD-like behavior based on video taken in a consultation room. We trained a machine learning classifier to differentiate between dogs clinically treated in the context of ADHD-like behavior and health control group with 81% accuracy; we then used its output to score the degree of exhibited ADHD-like behavior. In a preliminary evaluation in clinical context, in 8 out of 11 patients receiving medical treatment to treat excessive ADHD-like behavior, H-score was reduced. We further discuss the potential applications of the provided artifacts in clinical settings, based on feedback on H-score received from a focus group of four behavior experts.

Prevalence, comorbidity, and breed differences in canine anxiety in 13,700 Finnish pet dogs

Behaviour problems and anxieties in dogs decrease their quality of life and may lead to relinquishment or euthanasia. Considering the large number of pet dogs and the commonness of these problematic behaviours, a better understanding of the epidemiology and related molecular and environmental factors is needed. We have here studied the prevalence, comorbidity, and breed specificity of seven canine anxiety-like traits: noise sensitivity, fearfulness, fear of surfaces and heights, inattention/impulsivity, compulsion, separation related behaviour and aggression with an online behaviour questionnaire answered by dog owners. Our results show that noise sensitivity is the most common anxiety-related trait with a prevalence of 32% in 13,700 Finnish pet dogs. Due to the high prevalence of noise sensitivity and fear, they were the most common comorbidities. However, when comparing the relative risk, the largest risk ratios were seen between hyperactivity/inattention, separation related behaviour and compulsion, and between fear and aggression. Furthermore, dog breeds showed large differences in prevalence of all anxiety-related traits, suggesting a strong genetic contribution. As a result, selective breeding focusing on behaviour may reduce the prevalence of canine anxieties. Anxious animals may suffer from chronic stress and thus, modified breeding policies could improve the welfare of our companion dogs.

Computational Analysis of Movement Patterns of Dogs with ADHD-Like Behavior

Simple Summary

ADHD-like (attention deficit hyperactivity disorder) behavior in dogs may be expressed as impulsivity, inattentiveness, or aggression, compromising both dog and owner quality of life. Its treatment in a clinical setting requires behavioral modification and sometimes a medical treatment is added. There is a lack of objective tools for assessment and diagnosis of the problem, and behavioral experts mostly rely on owner reports. To address this gap, in this paper we use a self-developed computational tool which automatically analyzes movement of a dog from video footage collected during behavioral consultation. Based on a computational analysis of behavioral consultations of 12 dogs medically treated due to ADHD-like behavior and of a control group of 12 dogs with no reported behavioral problems, we identify three dimensions of characteristic movement patterns of dogs with ADHD-like behaviors, which are detectable during consultation. These include (i) high speed of movement, (ii) large coverage of room space, and (iii) frequent re-orientation in room space. These patterns can form the basis for computational methods for objective assessment of dogs with ADHD-like behavior that could help for diagnosis and clinical treatment of the disorder.

Abstract

Computational approaches were called for to address the challenges of more objective behavior assessment which would be less reliant on owner reports. This study aims to use computational analysis for investigating a hypothesis that dogs with ADHD-like (attention deficit hyperactivity disorder) behavior exhibit characteristic movement patterns directly observable during veterinary consultation. Behavioral consultations of 12 dogs medically treated due to ADHD-like behavior were recorded, as well as of a control group of 12 dogs with no reported behavioral problems. Computational analysis with a self-developed tool based on computer vision and machine learning was performed, analyzing 12 movement parameters that can be extracted from automatic dog tracking data. Significant differences in seven movement parameters were found, which led to the identification of three dimensions of movement patterns which may be instrumental for more objective assessment of ADHD-like behavior by clinicians, while being directly observable during consultation. These include (i) high speed, (ii) large coverage of space, and (iii) constant re-orientation in space. Computational tools used on video data collected during consultation have the potential to support quantifiable assessment of ADHD-like behavior informed by the identified dimensions.

Convolutional neural networks for decoding of covert attention focus and saliency maps for EEG feature visualization

OBJECTIVE

Convolutional neural networks (CNNs) have proven successful as function approximators and have therefore been used for classification problems including electroencephalography (EEG) signal decoding for brain-computer interfaces (BCI). Artificial neural networks, however, are considered black boxes, because they usually have thousands of parameters, making interpretation of their internal processes challenging. Here we systematically evaluate the use of CNNs for EEG signal decoding and investigate a method for visualizing the CNN model decision process.

APPROACH

We developed a CNN model to decode the covert focus of attention from EEG event-related potentials during object selection. We compared the CNN and the commonly used linear discriminant analysis (LDA) classifier performance, applied to datasets with different dimensionality, and analyzed transfer learning capacity. Moreover, we validated the impact of single model components by systematically altering the model. Furthermore, we investigated the use of saliency maps as a tool for visualizing the spatial and temporal features driving the model output.

MAIN RESULTS

The CNN model and the LDA classifier achieved comparable accuracy on the lower-dimensional dataset, but CNN exceeded LDA performance significantly on the higher-dimensional dataset (without hypothesis-driven preprocessing), achieving an average decoding accuracy of 90.7% (chance level  =  8.3%). Parallel convolutions, tanh or ELU activation functions, and dropout regularization proved valuable for model performance, whereas the sequential convolutions, ReLU activation function, and batch normalization components reduced accuracy or yielded no significant difference. Saliency maps revealed meaningful features, displaying the typical spatial distribution and latency of the P300 component expected during this task.

SIGNIFICANCE

Following systematic evaluation, we provide recommendations for when and how to use CNN models in EEG decoding. Moreover, we propose a new approach for investigating the neural correlates of a cognitive task by training CNN models on raw high-dimensional EEG data and utilizing saliency maps for relevant feature extraction.

Ethical and Scientific Pitfalls Concerning Laboratory Research with Non-Human Primates, and Possible Solutions

Basic and applied laboratory research, whenever intrusive or invasive, presents substantial ethical challenges for ethical committees, be it with human beings or with non-human animals. In this paper we discuss the use of non-human primates (NHPs), mostly as animal models, in laboratory based research. We examine the two ethical frameworks that support current legislation and guidelines: deontology and utilitarianism. While human based research is regulated under deontological principles, guidelines for laboratory animal research rely on utilitarianism. We argue that the utilitarian framework is inadequate for this purpose: on the one hand, it is almost impossible to accurately predict the benefits of a study for all potential stakeholders; and on the other hand, harm inflicted on NHPs (and other animals) used in laboratory research is extensive despite the increasing efforts of ethics committees and the research community to address this. Although deontology and utilitarianism are both valid ethical frameworks, we advocate that a deontological approach is more suitable, since we arguably have moral duties to NHPs. We provide suggestions on how to ensure that research currently conducted in laboratory settings shifts towards approaches that abide by deontological principles. We assert that this would not impede reasonable scientific research.

Development and validation of the Canine Reward Responsiveness Scale -Examining individual differences in reward responsiveness of the domestic dog

Although there is ample data indicating that reward processing plays an important role in human psychopathologies and pharmaco- and psychotherapy treatment response, the corresponding animal-model research needs to be extended to models whose motivational and social dispositions are better generalizable than those of the traditional models. Accordingly, our aim was to develop and assess the reliability and validity of an owner-report rating scale of reward responsiveness in domestic dogs (N = 2149) and then to examine individual differences in reward responsiveness. Responsiveness was categorisable by reward type (ball/toy and food) and exhibited individual variability manifesting in age- and breed-related differences. Rating scale scores were associated with behavioural observation of reward processing, indicating evidence of convergent validity. Ball/toy and food reward responsiveness were associated with owner-rated hyperactivity-impulsivity‚ inattention and with differences in training, indicating evidence of concurrent validity. Extreme (vs. average) reward responsiveness was also predicted by dogs’ hyperactivity-impulsivity and inattention‚ and extreme responsiveness was associated with increased likelihood of physical health and/or social problems. These findings are informative with regard to the dog as an animal model for various human behavioural and cognitive functions‚ and also for the dog in its own right as they are relevant to training and welfare.

Cognitive Aging in Dogs

A decline in the physical or mental health of older dogs can be a challenge for the owners, whose relationship with their dog is compromised by the cognitive and behavioral changes in their dogs. Although dog owners tend to consider many physiological and behavioral changes in old dogs as part of the normal aging process, it is important to differentiate between normal aging and pathologic aging, since behavioral changes may be the first indication of declining health and welfare in old dogs. Most reviews on cognitive aging in dogs have focused on translational approaches to human Alzheimer's disease; from a practical perspective, however, understanding normal cognitive aging in pet dogs and screening cognitively affected dogs are important in their own right. Here we review the literature on different cognitive functions that decline during aging, signs of cognitive dysfunction, screening methods, and preventive measures for age-related cognitive decline. Moreover, we discuss the drawbacks of using questionnaires as subjective measures of aging and propose the development of objective methods to distinguish normal cognitive aging from severe cognitive dysfunction. We suggest that multi-targeted approaches that combine owner-evaluated questionnaires with neuropsychological tests can be most effective in screening cognitively affected dogs from normally aging dogs. Regarding preventive measures, we conclude that combinations of dietary intervention and behavioral enrichment may be more beneficial than single-pathway manipulations in delaying cognitive aging or retaining various cognitive functions during aging.

Emergence of chimeras through induced multistability

Chimeras, namely coexisting desynchronous and synchronized dynamics, are formed in an ensemble of identically coupled identical chaotic oscillators when the coupling induces multiple stable attractors, and further when the basins of the different attractors are intertwined in a complex manner. When there is coupling-induced multistability, an ensemble of identical chaotic oscillators-with global coupling, or also under the influence of common noise or an external drive (chaotic, periodic, or quasiperiodic)-inevitably exhibits chimeric behavior. Induced multistability in the system leads to the formation of distinct subpopulations, one or more of which support synchronized dynamics, while in others the motion is asynchronous or incoherent. We study the mechanism for the emergence of such chimeric states, and we discuss the generality of our results.

A non-targeted metabolite profiling pilot study suggests that tryptophan and lipid metabolisms are linked with ADHD-like behaviours in dogs

BACKGROUND

Attention deficit hyperactivity disorder (ADHD) is a prevalent and multifactorial neuropsychiatric disorder in the human population worldwide. Complex etiology and clinical heterogeneity have challenged the research, diagnostics and treatment of the disease. Hyperactive and impulsive behaviour has also been observed in dogs, and they could offer a physiologically relevant model for human ADHD. As a part of our ongoing study to understand the molecular etiology of canine anxiety traits, this study was aimed to pilot an approach to identify metabolic biomarkers in canine ADHD-like behaviours for research, diagnostics and treatment purposes.

METHODS

We collected fresh plasma samples from 22 German Shepherds with varying ADHD-like behaviours. All dogs were on the same controlled diet for 2 weeks prior to sampling. A liquid chromatography combined with mass spectrometry (LC-MS)-based non-targeted metabolite profiling was performed to identify plasma metabolites correlating with the ADHD-like behaviour of the dogs.

RESULTS

649 molecular features correlated with ADHD-like behavioural scores (p_raw < 0.05), and three of them [sn-1 LysoPC(18:3), PC(18:3/18:2) and sn-1 LysoPE(18:2)] had significant correlations also after FDR correction (pFDR < 0.05). Phospholipids were found to negatively correlate with ADHD-like behavioural scores, whereas tryptophan metabolites 3-indolepropionic acid (IPA) and kynurenic acid (KYNA) had negative and positive correlations with ADHD-like behavioural scores, respectively.

CONCLUSIONS

Our study identified associations between canine ADHD-like behaviours and metabolites that are involved in lipid and tryptophan metabolisms. The identified metabolites share similarity with earlier findings in human and rodent ADHD models. However, a larger replication study is warranted to validate the discoveries prior to further studies to understand the biological role of the identified metabolites in canine ADHD-like behaviours.

Anti-inflammation Effects of Oxysophoridine on Cerebral Ischemia-Reperfusion Injury in Mice

Oxysophoridine (OSR) is a bioactive alkaloid extracted from the Sophora alopecuroides Linn. Our aim is to explore the potential anti-inflammation mechanism of OSR in cerebral ischemic injury. Mice were intraperitoneally pretreated with OSR (62.5, 125, and 250 mg/kg) or nimodipine (Nim) (6 mg/kg) for 7 days followed by cerebral ischemia. The inflammatory-related cytokines in cerebral ischemic hemisphere tissue were determined by immunohistochemistry staining, Western blot and enzyme-like immunosorbent assay (ELISA). OSR-treated groups observably suppressed the nuclear factor kappa B (NF-κB), intercellular adhesion molecule-1 (ICAM-1), inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2). OSR-treated group (250 mg/kg) markedly reduced the inflammatory-related protein prostaglandin E2 (PGE2), tumor necrosis factor alpha (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6), and interleukin-8 (IL-8). Meanwhile, it dramatically increased the interleukin-10 (IL-10). Our study revealed that OSR protected neurons from ischemia-induced injury in mice by downregulating the proinflammatory cytokines and blocking the NF-κB pathway.

A comparison of rating and coding behavioural traits in dogs

The aim of the present study was to examine the links between independent rating and coding approaches to assessing activity-impulsivity and inattention in dogs. Fifty-six adult Belgian shepherd dogs were videotaped performing in behavioural tests. Seventeen behavioural variables were measured by coders (video coding). Raters watched the same videotapes and then rated the activity-impulsivity and inattention of each dog (video rating). Owners filled out the Dog ADHS-RS questionnaire measuring activity-impulsivity and inattention. Video rating of activity-impulsivity correlated with the scale scores of the owner, but video codings did not. The results suggest that the owner ratings and video ratings are tapping the same constructs, but behavioural variables assessed in the present study were not appropriate for mirroring the owners' assessments. The findings suggest that if consistent individual differences in broad behavioural traits are the primary focus of analyses, then ratings seem to capture information not easily captured in coding approaches designed to assess the same constructs.

Lifespan development of attentiveness in domestic dogs: drawing parallels with humans

Attention is pivotal to consciousness, perception, cognition, and working memory in all mammals, and therefore changes in attention over the lifespan are likely to influence development and aging of all of these functions. Due to their evolutionary and developmental history, the dog is being recognized as an important species for modeling human healthspan, aging and associated diseases. In this study, we investigated the normal lifespan development of attentiveness of pet dogs in naturalistic situations, and compared the resulting cross-sectional developmental trajectories with data from previous studies in humans. We tested a sample of 145 Border collies (6 months to 14 years) with humans and objects or food as attention attractors, in order to assess their attentional capture, sustained and selective attention, and sensorimotor abilities. Our results reveal differences in task relevance in sustained attentional performance when watching a human or a moving object, which may be explained by life-long learning processes involving such stimuli. During task switching we found that dogs' selective attention and sensorimotor abilities showed differences between age groups, with performance peaking at middle age. Dogs' sensorimotor abilities showed a quadratic distribution with age and were correlated with selective attention performance. Our results support the hypothesis that the development and senescence of sensorimotor and attentional control may be fundamentally interrelated. Additionally, attentional capture, sustained attention, and sensorimotor control developmental trajectories paralleled those found in humans. Given that the development of attention is similar across humans and dogs, we propose that the same regulatory mechanisms are likely to be present in both species. Finally, this cross-sectional study provides the first description of age group changes in attention over the lifespan of pet dogs.

Characterization of a dopamine transporter polymorphism and behavior in Belgian Malinois

BACKGROUND

The Belgian Malinois dog breed (MAL) is frequently used in law enforcement and military environments. Owners have reported seizures and unpredictable behavioral changes including dogs' eyes "glazing over," dogs' lack of response to environmental stimuli, and loss of behavioral inhibition including owner-directed biting behavior. Dogs with severe behavioral changes may be euthanized as they can represent a danger to humans and other dogs. In the dog, the dopamine transporter gene (DAT) contains a 38-base pair variable number tandem repeat (DAT-VNTR); alleles have either one or two copies of the 38-base pair sequence. The objective of this study was to assess frequency of DAT-VNTR alleles, and characterize the association between DAT-VNTR alleles and behavior in MAL and other breeds.

RESULTS

In an American sample of 280 dogs comprising 26 breeds, most breeds are predominantly homozygous for the DAT-VNTR two-tandem-repeat allele (2/2). The one-tandem-repeat allele is over-represented in American MAL (AM-MAL) (n = 144), both as heterozygotes (1/2) and homozygotes (1/1). All AM-MAL with reported seizures (n = 5) were 1/1 genotype. For AM-MAL with at least one "1" allele (1/1 or 1/2 genotype, n = 121), owners reported higher levels of attention, increased frequency of episodic aggression, and increased frequency of loss of responsiveness to environmental stimuli. In behavior observations, Belgian Military Working Dogs (MWD) with 1/1 or 1/2 genotypes displayed fewer distracted behaviors and more stress-related behaviors such as lower posture and increased yawning. Handlers' treatment of MWD varied with DAT-VNTR genotype as did dogs' responses to handlers' behavior. For 1/1 or 1/2 genotype MWD, 1) lower posture after the first aversive stimulus given by handlers was associated with poorer obedience performance; 2) increased aversive stimuli during protection exercises were associated with decreased performance; 3) more aversive stimuli during obedience were associated with more aversive stimuli during protection; and 4) handlers used more aversive stimuli in protection compared with obedience exercises.

CONCLUSIONS

The single copy allele of DAT-VNTR is associated with owner-reported seizures, loss of responsiveness to environmental stimuli, episodic aggression, and hyper-vigilance in MAL. Behavioral changes are associated with differential treatment by handlers. Findings should be considered preliminary until replicated in a larger sample.

DRD4 and TH gene polymorphisms are associated with activity, impulsivity and inattention in Siberian Husky dogs

Both dopamine receptor D4 (DRD4) exon 3 and tyrosine hydroxylase (TH) intron 4 repeat polymorphisms have been linked to activity and impulsivity in German Shepherd dogs (GSDs). However, the results in GSDs may not be generalisable to other breeds, as allelic frequencies vary markedly among breeds. We selected the Siberian Husky for further study, because it is highly divergent from most dog breeds, including the GSD. The study sample consisted of 145 racing Siberian Huskies from Europe and North America. We found that this breed possesses seven DRD4 length variants, two to five more variants than found in other breeds. Among them was the longest known allele, previously described only in wolves. Short alleles of the DRD4 and TH repeat polymorphisms were associated with higher levels of activity, impulsivity and inattention. Siberian Huskies possessing at least one short allele of the DRD4 polymorphism displayed greater activity in a behavioural test battery than did those with two long alleles. However, the behavioural test was brief and may not have registered variation in behaviour across time and situations. Owners also completed the Dog-Attention Deficit Hyperactivity Disorder Rating Scale (Dog-ADHD RS), a more general measure of activity and attention. Siberian Huskies from Europe with two short alleles of the TH polymorphism received higher ratings of inattention on the Dog-ADHD RS than did those with the long allele. Investigation of the joint effect of DRD4 and TH showed that dogs possessing long alleles at both sites were scored as less active-impulsive than were others. Our results are aligned with previous studies showing that DRD4 and TH polymorphisms are associated with activity-impulsivity related traits in dogs. However, the prevalence of variants of these genes differs across breeds, and the functional role of specific variants is unclear.