Open field activity and human interaction as a function of age and breed in dogs

Age and Physical Activity Levels in Companion Dogs: Results From the Dog Aging Project

While there has been an abundance of studies on the important relationship between physical activity and age in both dogs and humans, studies on dogs have primarily focused on how a dog's biological characteristics, such as their weight, affect the age-activity relationship. To date, there is little knowledge about how this relationship may be associated with contextual- and owner-level characteristics. We leveraged a large and novel data set from the Dog Aging Project (DAP) to investigate the extent to which the age-activity relationship is associated with certain dog and owner characteristics, namely dog size, owner age, and the environment in which they live. Dogs are a unique model for aging research as they are exposed to similar social and environmental elements as humans but have a shorter life span, allowing researchers to observe their entire life course. We find that older dogs are less active than younger dogs; rural dogs are more active than suburban and urban dogs, especially at younger ages; and larger dogs are more active than smaller dogs. These findings are generally consistent with previous studies. However, a surprising finding is that older owners have more active dogs than younger owners. As one of the first studies to utilize the large survey data from the DAP, this study lays the foundation for future investigations to further understand and identify the biological, social, and environmental causes, as well as consequences, of aging.

Dog cognitive development: a longitudinal study across the first 2 years of life

While our understanding of adult dog cognition has grown considerably over the past 20 years, relatively little is known about the ontogeny of dog cognition. To assess the development and longitudinal stability of cognitive traits in dogs, we administered a battery of tasks to 160 candidate assistance dogs at 2 timepoints. The tasks were designed to measure diverse aspects of cognition, ranging from executive function (e.g., inhibitory control, reversal learning, memory) to sensory discrimination (e.g., vision, audition, olfaction) to social interaction with humans. Subjects first participated as 8-10-week-old puppies, and then were retested on the same tasks at ~ 21 months of age. With few exceptions, task performance improved with age, with the largest effects observed for measures of executive function and social gaze. Results also indicated that individual differences were both early emerging and enduring; for example, social attention to humans, use of human communicative signals, independent persistence at a problem, odor discrimination, and inhibitory control all exhibited moderate levels of rank-order stability between the two timepoints. Using multiple regression, we found that young adult performance on many cognitive tasks could be predicted from a set of cognitive measures collected in early development. Our findings contribute to knowledge about changes in dog cognition across early development as well as the origins and developmental stability of individual differences.

Individual and group level personality change across the lifespan in dogs

In humans, age-related changes in personality occur in a non-random fashion with respect to their direction, timing, and magnitude. In dogs, there are still gaps in our knowledge about the detailed dynamics of age-related personality changes. We analysed the personality of 217 Border collies aged from 0.5 to 15 years both cross-sectionally and longitudinally using a test battery, to specify age periods when changes most prominently occur, assess the magnitude of changes, and analyse individual differences in personality change. We found that similar to humans, changes in personality occur unevenly during the dogs’ life course, however, their dynamics seems to be specific for each trait. Activity-independence decreased mostly from puppyhood (0.5–1 years) to adolescence (> 1–2 years), then continued to decrease in a slowing rate. Novelty seeking did not change markedly until middle age (> 3–6 years), then showed a steady linear decrease. Problem orientation increased strongly until middle age then showed no marked changes in later age periods. We also revealed individual differences in personality change over time, and showed that a few individuals with potential age-related impairments significantly affected the general age trajectory of some traits. These results raise caution against the over-generalisation of global age trends in dogs.

Effects of Olfactory and Auditory Enrichment on the Behaviour of Shelter Dogs

Shelter environments are stressful for dogs, as they must cope with many stimuli over which they have little control. This can lead to behavioural changes, negatively affect their welfare and downgrade the human-animal bond, affecting re-homing success. Arousal is evident in their behaviour, particularly increased activity and frequent vocalisation. Environmental enrichment plays an important role in reducing arousal behaviour, either through direct physiological effects or by masking stressful stimuli. The present study focused on sensory environmental enrichment, using olfactory and auditory stimuli under shelter conditions. Sixty dogs were allocated to one of four treatments: three types of enrichment, Lavender, Dog appeasing pheromone (DAP) and Music, and a Control group. Stimuli were applied for 3 h/d on five consecutive days. Dogs exposed to DAP lay down more, and those exposed to Music lay down more with their head down, compared to the Control. Those in the Control stood more on their hind legs with their front legs on the exit door, compared to those exposed to Music and DAP, particularly if they had only been in the shelter for a short time. They also panted and vocalised much more than dogs in the three enrichment treatments, which tended to persist during the 4 h period post treatment, and in the case of vocalisation into the subsequent night. The study suggests that all three enrichments had some positive benefits for dogs in shelters, as well as being non-invasive and easy to apply in the shelter environment.

Personality traits in companion dogs-Results from the VIDOPET

Individual behavioural differences in pet dogs are of great interest from a basic and applied research perspective. Most existing dog personality tests have specific (practical) goals in mind and so focused only on a limited aspect of dogs' personality, such as identifying problematic (aggressive or fearful) behaviours, assessing suitability as working dogs, or improving the results of adoption. Here we aimed to create a comprehensive test of personality in pet dogs that goes beyond traditional practical evaluations by exposing pet dogs to a range of situations they might encounter in everyday life. The Vienna Dog Personality Test (VIDOPET) consists of 15 subtests and was performed on 217 pet dogs. A two-step data reduction procedure (principal component analysis on each subtest followed by an exploratory factor analysis on the subtest components) yielded five factors: Sociability-obedience, Activity-independence, Novelty seeking, Problem orientation, and Frustration tolerance. A comprehensive evaluation of reliability and validity measures demonstrated excellent inter- and intra-observer reliability and adequate internal consistency of all factors. Moreover the test showed good temporal consistency when re-testing a subsample of dogs after an average of 3.8 years-a considerably longer test-retest interval than assessed for any other dog personality test, to our knowledge. The construct validity of the test was investigated by analysing the correlations between the results of video coding and video rating methods and the owners' assessment via a dog personality questionnaire. The results demonstrated good convergent as well as discriminant validity. To conclude, the VIDOPET is not only a highly reliable and valid tool for measuring dog personality, but also the first test to show consistent behavioural traits related to problem solving ability and frustration tolerance in pet dogs.

Learning, memory and exploratory similarities in genetically identical cloned dogs

Somatic cell nuclear transfer allows generation of genetically identical animals using donor cells derived from animals with particular traits. To date, few studies have investigated whether or not these cloned dogs will show identical behavior patterns. To address this question, learning, memory and exploratory patterns were examined using six cloned dogs with identical nuclear genomes. The variance of total incorrect choice number in the Y-maze test among cloned dogs was significantly lower than that of the control dogs. There was also a significant decrease in variance in the level of exploratory activity in the open fields test compared to age-matched control dogs. These results indicate that cloned dogs show similar cognitive and exploratory patterns, suggesting that these behavioral phenotypes are related to the genotypes of the individuals.

Pathology of the Aging Brain in Domestic and Laboratory Animals, and Animal Models of Human Neurodegenerative Diseases

According to the WHO, the proportion of people over 60 years is increasing and expected to reach 22% of total world’s population in 2050. In parallel, recent animal demographic studies have shown that the life expectancy of pet dogs and cats is increasing. Brain aging is associated not only with molecular and morphological changes but also leads to different degrees of behavioral and cognitive dysfunction. Common age-related brain lesions in humans include brain atrophy, neuronal loss, amyloid plaques, cerebrovascular amyloid angiopathy, vascular mineralization, neurofibrillary tangles, meningeal osseous metaplasia, and accumulation of lipofuscin. In aging humans, the most common neurodegenerative disorder is Alzheimer’s disease (AD), which progressively impairs cognition, behavior, and quality of life. Pathologic changes comparable to the lesions of AD are described in several other animal species, although their clinical significance and effect on cognitive function are poorly documented. This review describes the commonly reported age-associated neurologic lesions in domestic and laboratory animals and the relationship of these lesions to cognitive dysfunction. Also described are the comparative interspecies similarities and differences to AD and other human neurodegenerative diseases including Parkinson’s disease and progressive supranuclear palsy, and the spontaneous and transgenic animal models of these diseases.

The Use of an Open Field Model to Assess Sound-Induced Fear and Anxiety Associated Behaviors in Labrador Retrievers

Previous studies have shown that the playing of thunderstorm recordings during an open-field task elicits fearful or anxious responses in adult beagles. The goal of our study was to apply this open field test to assess sound-induced behaviors in Labrador retrievers drawn from a pool of candidate improvised explosive devices (IED)-detection dogs. Being robust to fear-inducing sounds and recovering quickly is a critical requirement of these military working dogs. This study presented male and female dogs, with 3 minutes of either ambient noise (Days 1, 3 and 5), recorded thunderstorm (Day 2), or gunfire (Day 4) sounds in an open field arena. Behavioral and physiological responses were assessed and compared to control (ambient noise) periods. An observer blinded to sound treatment analyzed video records of the 9-minute daily test sessions. Additional assessments included measurement of distance traveled (activity), heart rate, body temperature, and salivary cortisol concentrations. Overall, there was a decline in distance traveled and heart rate within each day and over the five-day test period, suggesting that dogs habituated to the open field arena. Behavioral postures and expressions were assessed using a standardized rubric to score behaviors linked to canine fear and anxiety. These fear/anxiety scores were used to evaluate changes in behaviors following exposure to a sound stressor. Compared to control periods, there was an overall increase in fear/anxiety scores during thunderstorm and gunfire sound stimuli treatment periods. Fear/anxiety scores were correlated with distance traveled, and heart rate. Fear/anxiety scores in response to thunderstorm and gunfire were correlated. Dogs showed higher fear/anxiety scores during periods after the sound stimuli compared to control periods. In general, candidate IED-detection Labrador retrievers responded to sound stimuli and recovered quickly, although dogs stratified in their response to sound stimuli. Some dogs were robust to fear/anxiety responses. The results suggest that the open field sound test may be a useful method to evaluate the suitability of dogs for IED-detection training.

Prevention approaches in a preclinical canine model of Alzheimer's disease: benefits and challenges

Aged dogs spontaneously develop many features of human aging and Alzheimer's disease (AD) including cognitive decline and neuropathology. In this review, we discuss age-dependent learning tasks, memory tasks, and functional measures that can be used in aged dogs for sensitive treatment outcome measures. Neuropathology that is linked to cognitive decline is described along with examples of treatment studies that show reduced neuropathology in aging dogs (dietary manipulations, behavioral enrichment, immunotherapy, and statins). Studies in canine show that multi-targeted approaches may be more beneficial than single pathway manipulations (e.g., antioxidants combined with behavioral enrichment). Aging canine studies show good predictive validity for human clinical trials outcomes (e.g., immunotherapy) and several interventions tested in dogs strongly support a prevention approach (e.g., immunotherapy and statins). Further, dogs are ideally suited for prevention studies as they the age because onset of cognitive decline and neuropathology strongly support longitudinal interventions that can be completed within a 3-5 year period. Disadvantages to using the canine model are that they lengthy, use labor-intensive comprehensive cognitive testing, and involve costly housing (almost as high as that of non-human primates). However, overall, using the dog as a preclinical model for testing preventive approaches for AD may complement work in rodents and non-human primates.

A canine model of human aging and Alzheimer's disease

The aged dog naturally develops cognitive decline in many different domains (including learning and memory) but also exhibits human-like individual variability in the aging process. The neurobiological basis for cognitive dysfunction may be related to structural changes that reflect neurodegeneration. Molecular cascades that contribute to degeneration in the aging dog brain include the progressive accumulation of beta-amyloid (Aβ) in diffuse plaques and in the cerebral vasculature. In addition, neuronal dysfunction occurs as a consequence of mitochondrial dysfunction and cumulative oxidative damage. In combination, the aged dog captures key features of human aging, making them particularly useful for the development of preventive or therapeutic interventions to improve aged brain function. These interventions can then be translated into human clinical trials. This article is part of a Special Issue entitled: Animal Models of Disease.

Relevance of animal models of subarachnoid hemorrhage for examining neurobehavioral changes

BACKGROUND AND PURPOSE

For many years survival and neurological functionality of patients were the main outcome measures after treatment of intracranial aneurysms. But, the variable outcomes of patients operated on in a delayed fashion or before the aneurysm rupture indicate that more precise measures are needed for assessment of not only the neurological but also the neuropsychological outcome. However, development and testing of such new tools requires better understanding of pathomechanisms of neurobehavioral changes evoked by aneurysmal subarachnoid hemorrhage (aSAH), which can be achieved using animal models.

METHODS

We reviewed and selected (1) animal models developed to investigate delayed cerebral vasospasm that could be useful for examining effects of brain injury evoked by aSAH and (2) a battery of neurobehavioral animal testing that can be used for assessment of patients after aSAH.

RESULTS

For every species used as an aSAH model, a battery of neurobehavioral test exists.

CONCLUSION

Albeit some limitations must be recognized, research using animal models of SAH should continue to play a critical role in assessment of cognitive and behavioral functions after aSAH.

Human interaction moderates plasma cortisol and behavioral responses of dogs to shelter housing

Housing in an animal shelter is a stressful experience for dogs. This study examined the effects of different forms of human interaction on concentrations of circulating cortisol and stress-related behaviors of dogs within 40 h of admittance to a county animal shelter. Blood samples were collected before and after 30-min sessions in a secluded area in which dogs received one of three forms of human interaction: exposure to a passive human, petting, or play. Controls were either exposed to the secluded area alone, or remained in the general housing area. There was a substantial and near uniform reduction in plasma cortisol concentrations from pretest to post-test in all three conditions receiving human interaction, but not in control conditions. Human interaction also reduced behavioral signs of excitation/social solicitation (vocalizing) and fear (panting). Finally, pretest cortisol levels were found to predict levels of panting and another fear-related behavior (tongue protrusions) that dogs exhibited during subsequent testing. The findings suggest practical means of reducing stress, and potentially of improving the welfare, of dogs in shelters.

Effect of age and severity of cognitive dysfunction on spontaneous activity in pet dogs - part 1: locomotor and exploratory behaviour

Age-related cognitive dysfunction syndrome (CDS) has been reported in dogs and it is considered a natural model for Alzheimer's disease in humans. Changes in spontaneous activity (including locomotor and exploratory behaviour) and social responsiveness have been related to the age and cognitive status of kennel-reared Beagle dogs. The aim of this study was to assess the influence of age and severity of CDS on locomotor and exploratory behaviour of privately owned dogs. This is the first part of a two-part report on spontaneous activity in pet dogs. An open-field (OF) test and a curiosity test were administered at baseline and 6 months later to young (1-4 years, n=9), middle-aged (5-8 years, n=9), cognitively unimpaired aged (≥ 9 years, n=31), and cognitively impaired aged ( ≥ 9 years, n=36) animals. Classification of cognitive status was carried out using an owner-based observational questionnaire, and in the cognitively impaired group, the dogs were categorised as having either mild or severe cognitive impairment. Dogs were recorded during sessions in the testing room and the video-recordings were subsequently analysed. The severity of CDS (but not age) influenced locomotion and exploratory behaviour so that the more severe the impairment, the higher the locomotor activity and frequency of corner-directed (aimless) behaviours, and the lower the frequency of door-aimed activities. Curiosity directed toward novel stimuli exhibited an age-dependent decline although severely affected animals displayed more sniffing episodes directed towards the objects. OF activity did not change after 6 months. Testing aged pet dogs for spontaneous behaviour might help to better characterise cognitively affected individuals.

Effect of age and severity of cognitive dysfunction on spontaneous activity in pet dogs - part 2: social responsiveness

Changes in social interactions with owners and other dogs are frequently observed in dogs with cognitive dysfunction syndrome (CDS). The aim of this work was to assess the effect of age and severity of CDS on social responsiveness. This is the second part of a 2-part report on spontaneous activity in pet dogs. A human interaction test and a mirror test were administered at baseline and 6 months later to assess social responses to humans and conspecifics, respectively, to four groups of privately-owned dogs: young (n=9), middle-aged (n=9), cognitively unimpaired aged (n=31), and cognitively impaired aged (n=36). The severity of cognitive impairment was considered in the last group and dogs were categorised as having either mild or severe CDS. The influence of the person and the mirror on locomotion and exploratory behaviour was also studied. Dogs were recorded in a testing room and the video recordings were subsequently analysed. Young dogs displayed more interactions involving physical contact with a person. Young and middle-aged dogs showed more vocalisations in response to social isolation. In contrast, aged animals spent more time in front of the mirror. Changes in social responsiveness associated with severe CDS included decreased response to social isolation and human interaction and increased time in front of the mirror, suggesting a deficit in habituation. Testing of spontaneous activity might help to characterise CDS in aged dogs, a condition increasingly diagnosed in veterinary clinics and a potentially useful natural model of Alzheimer's disease in humans.

Cortisol and behavioral responses of working dogs to environmental challenges

This paper's primary objective is to analyse the physiological (cortisol) and behavioral responses of military working dogs (MWD). Dogs (N=27) were submitted twice to environmental challenges (challenge 1 and 2, 20 days in-between) composed of social (training), visual (mobile toy car) and auditory (air blast) stimuli. Cortisol levels decreased back to the baseline after the second challenge. The behavioral observations showed that these MWD were more active, and presented less stereotypic behaviors (pacing, manipulation of the environment) during both visual challenges, whereas half low posture was observed during the first but not during the second visual challenge. The present study shows that this group of MWD still has an adaptation capacity to an environmental challenge (return to baseline of the cortisol levels, a higher posture during the second than at the first challenge). These results are encouraging and indicate that the dogs might have a diminished welfare (i.e. stereotypic behaviors), but are not chronically stressed.

Behavioural and glucocorticoid responses of dogs (Canis familiaris) to kennelling: Investigating mitigation of stress by prior habituation

We have explored the validity of urinary cortisol/creatinine ratios (C/C) and behavioural measures as indicators of acute psychological stress in the domestic dog, by monitoring 1 year old male Labrador Retrievers (N=31) prior to and following their introduction to novel kennels in a training establishment. Baseline early morning urine samples were taken in the dogs' original homes and then urine samples and remote recordings of behaviour were taken for ten consecutive days after transfer to the kennels. The impact of this potential stressor was manipulated by previously habituating half of the subjects to confinement in a kennel. We hypothesised that stress levels would increase upon introduction to the training establishment, but that the response would be mitigated by kennel habituation. C/C increased in all dogs when they entered the training establishment, this increase was significantly higher in the non-habituated group, and in this group C/C remained above baseline even 12 weeks after transfer. Despite the homogeneity of the subjects, the behaviour measured showed very little correlation to the C/C ratios, and the changes in behaviour that were observed, such as decreases in whining and time spent at the front of the kennel, could equally be attributed to dogs learning the most effective strategies for gaining human attention in the kennels as to attenuation of stress. We conclude that urinary C/C is a valuable indicator of acute stress and hence welfare status in dogs, but that behavioural measures need to be interpreted with caution due to individuality in coping strategies.

Neurobehavioral functional deficits following closed head injury in the neonatal pig

Neurobehavioral deficits in higher cortical systems have not been described previously in a large animal model of diffuse brain injury. Anesthetized 3-5 day old piglets were subjected to either mild (142 rad/s) or moderate (188 rad/s) rapid non-impact axial rotations of the head. Multiple domains of cortical function were evaluated 5 times during the 12 day post-injury period using tests of neurobehavioral function devised for piglets. There were no observed differences in neurobehavioral outcomes between mild injury pigs (N=8) and instrumented shams (N=4). Moderately injured piglets (N=7) had significantly lower interest in exploring their environment and had higher failure rates in visual-based problem solving compared to instrumented shams (N=5) on days 1 and 4 after injury. Neurobehavioral functional deficits correlated with neuropathologic damage in the neonatal pigs after inertial head injury. Injured axons detected by immunohistochemistry (beta-APP) were absent in mild injury and sham piglets, but were observed in moderately injured piglet brains. In summary, we have developed a quantitative battery of neurobehavioral functional assessments for large animals that correlate with neuropathologic axonal damage and may have wide applications in the fields of cardiac resuscitation, stroke, and hypoxic-ischemic brain injury.

Region specific neuron loss in the aged canine hippocampus is reduced by enrichment

Neuron loss within the hippocampus and entorhinal cortex occurs as a function of age in humans. We first tested the hypothesis that neuron loss occurs in the aged dog. The total unilateral number of neurons in the canine entorhinal cortex and subdivisions of the hippocampus from the left hemisphere were estimated using the optical fractionator. The brains from 5 old (13.0-15.0 years old) and 5 young (3.4-4.5 years old) beagle dogs were analyzed. The hilus of the hippocampus showed a significant loss of neurons (approximately 30%) in the aged dog brain compared to young. Differences were not detected in the remaining hippocampal subfields and entorhinal cortex. We further tested the hypothesis that an antioxidant fortified food or behavioral enrichment would reduce the age-related loss of hilar neurons. Behaviorally enriched aged dogs had more neurons in the hilus (approximately 18%) compared to aged controls. These results suggest that the aged canine hippocampus in the left hemisphere shows selective neuron loss and that behavioral enrichment may reduce this loss.

Therapeutic agents for the treatment of cognitive dysfunction syndrome in senior dogs

With increasing age, dogs develop a form of neurodegenerative disease which has many similarities to age related cognitive impairment and Alzheimer's disease in humans. A decline in learning and memory can be demonstrated in dogs beginning as young as 7 years of age using a variety of neuropsychological tests. However, clinical cases of cognitive dysfunction syndrome are seldom identified until the age of 11 years or older. This is likely due to the fact that the owners are relying on clinical observations such as house-soiling, sleep-wake cycles and disorientation, rather than tests of learning and memory. On the other hand, dogs that are trained to more exacting tasks such as guide dogs for the visually impaired, or bomb detection and agility trained dogs might be noticed to have a decline in performance at a much earlier age. Through the use of standardized neuropsychological testing protocols, a number of drugs, natural products and supplement formulations have been developed for use in dogs with cognitive dysfunction and, in some cases clinical trials have validated their efficacy. Furthermore, the testing of products currently licensed and in the pipeline for the treatment of cognitive decline and Alzheimer's in humans, may provide additional therapeutic agents for the treatment of senior dogs, as well as provide insight as to the potential for the efficacy of these compounds in humans. This review will examine those products that are now marketed along with some that might be considered for use in senior dogs with cognitive dysfunction as well as the research that has been used to validate the efficacy (or lack thereof) of these compounds.

Preference formation and working memory in Parkinson's disease and normal ageing

Recent studies in rats have suggested that the amygdala and the dorsal striatum may be differentially involved in the formation of stimulus-reward associations and stimulus-response associations, respectively. In a recent study in humans, conditioned preference learning deficits were observed in a group of patients with damage to the amygdala formation. In this study, patients with Parkinson's disease, which is known to involve pathology of the dorsal striatum, were tested on the same conditioned preference task, together with a group of patients with circumscribed lesions of the frontal lobe. Unlike patients with frontal lobe damage, patients with Parkinson's disease did not exhibit conditioned preferences. However, in this respect their behaviour was indistinguishable from that of age-matched (older) control subjects. In keeping with previous literature, working memory deficits were observed in both patients with Parkinson's disease and patients with frontal-lobe lesions. Compared to young control subjects, a strong increase in preference for familiar, versus novel, items was observed in both patients with Parkinson's disease and in older control subjects. Such a familiarity effect appears to overshadow the conditioning manipulation employed in this task and, therefore, preclude the expression of conditioned preferences in older subjects. These results suggest that there is a developmental progression in the degree to which different mechanisms of 'learning to like' are important over the life span.

Age-dependent decline in locomotor activity in dogs is environment specific

A decrease in motor activity is an expected concomitant of normal aging and has been reported in humans and nonhuman mammals. We have previously failed to find age differences in open-field locomotor activity in beagle dogs. We now report an age-associated decline when activity measures are taken in the home cage. Locomotor activity of young and aged dogs was examined in both open-field and home-cage environments. Dogs were given six activity tests (two open field, two morning and two afternoon home-cage tests) every second day. Aged dogs were less active than young dogs in the home cage but not in the open field. Activity also varied as a function of sex and housing condition. Behavioral activity is a complex manifestation of many underlying factors.

Effect of age and level of cognitive function on spontaneous and exploratory behaviors in the beagle dog

Cognitively characterized young and aged beagle dogs were administered six different spontaneous behavior tests, which provided measures of locomotion, exploration, and social interaction. Consistent with our previous findings, we obtained no overall effect of age on locomotion. We did find, however, that for the aged dogs locomotion correlated with level of cognitive function, being lowest in age-unimpaired dogs and highest in impaired dogs. Exploratory behavior, as measured by response to novelty, varied with age, with young dogs scoring the highest. Young dogs spent more time with novel toys and a person, responded more to a silhouette of a dog, and interacted more with a model dog compared to aged dogs. Among the aged dogs, age-unimpaired dogs spent the greatest amount of time sitting or standing beside a person whereas age-impaired dogs spent the most time reacting to a reflection in a mirror. The age-impaired dogs show undirected, stereotypical types of behavioral patterns. These differences in activity patterns may be linked to underlying age-associated neuropathology.

Adrafinil: effects on behavior and cognition in aged canines

1. Adrafmil is a novel vigilance promoting agent developed in France by Louis Lafon Laboratories. 2. Adrafinil causes increased locomotion without producing stereotypical activity in canines tested in an open field. 3. The effectiveness of a single treatment is long-lasting, and the effectiveness persists over repeated treatments. 4. Acquisition of a size discrimination problem is enhanced by adrafinil. This may be linked to performance motivation. 5. Adrafinil causes a long-lasting increase in high frequency electroencephalographic activity recorded from cortical electrodes. 6. These results indicate that adrafinil is novel behavioral stimulant with cognitive enhancing potential. The underlying mechanisms of action are still unknown.

Behavioral activating effects of adrafinil in aged canines

Adrafinil, a vigilance enhancing pharmaceutical, was administered to aged dogs for 14 consecutive days at doses of 10, 20, 30, or 40 mg/kg using a crossover design. The effects on spontaneous behavior in a 10-min canine open-field test were systematically recorded every fourth day, starting with day 1 of treatment. The open field tests were given 2 or 10 h following oral administration of capsules containing either adrafinil or lactose, the placebo control. Adrafinil caused an increase in locomotor activity at the three highest doses at both the 2- and 10-h intervals and during both the first (days 1 and 5) and second treatment week (days 9 and 13). Adrafinil also caused a transient increase in directed sniffing. At the highest dose level, adrafinil caused a decrease in urination frequency. The increased locomotion was generally unaccompanied by stereotypical behavior in the test session. There was some variability; a subpopulation of animals showed either no effect, or decreased locomotion. The individual differences were correlated with changes in serum levels of adrafinil 10 h following treatment.