Balance control and posture differences in the anxious BALB/cByJ mice compared to the non anxious C57BL/6J mice

Combination of UPLC-Q-TOF/MS and network pharmacology to reveal the mechanism of Chaihu-jia-Longgu-Muli decoction for treating vertigo with anxiety disorder

Chaihu-jia-Longgu-Muli decoction (CLMD) has been proven clinically effective in treating vertigo with anxiety disorder. However, the mechanism is not clear. This study aimed to explore the mechanism of CLMD in treating vertigo with anxiety disorder based on ultra-performance liquid chromatography-quadrupole time-of-flight/mass spectrometry (UPLC-Q-TOF/MS) and network pharmacology. UPLC-Q-TOF/MS was performed to identify the compounds in blood and the targets of compounds of CLMD in vertigo and anxiety were searched using databases. A protein-protein interaction network was built to screen the core targets. The core targets were analyzed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses. In addition, the vertigo with anxiety rat model was used to verify the results. A total of 22 compounds were absorbed into the blood. Eighty-one potential targets associated with CLMD for vertigo with anxiety disorder were identified through network pharmacological analysis. Subsequently, GO and KEGG analysis showed that CLMD treatment for vertigo with anxiety disorder is associated with neurotransmitter levels and other pertinent physiological processes. The results of the animal experiments showed that CLMD decreased the levels of serotonin, norepinephrine and dopamine, alleviating the symptoms of vertigo and anxiety disorder in model rats. The study revealed CLMD could alleviate vertigo and anxiety symptoms through reducing the levels of neurotransmitters.

Eugenol and its liposome-based nano carrier reduce anxiety by inhibiting glyoxylase-1 expression in mice

The most common form of psycho-social dysfunction is anxiety with depression being related closely without any age bar. They are present with combined state of sadness, confusion, stress, fear etc. Glyoxalase system contains enzyme named glyoxalase 1 (GLO1).It is a metabolic pathway which detoxifies alpha-oxo-aldehydes, particularly methylglyoxal (MG). Methylglyoxal is mainly made by the breakdown of the glycolytic intermediates, glyceraldehyde-3-phosphates and dihydroxyacetone phosphate. Glyoxylase-1 expression is also related with anxiety behavior. A casual role or GLO-1 in anxiety behavior by using viral vectors for over expression in the anterior cingulate cortex was found and it was found that local GLO-1 over expression increased anxiety behavior. The present study deals with the molecular mechanism of protective activity of eugenol against anxiolytic disorder. A pre-clinical animal study was performed on 42 BALB/c mice. Animals were given stress through conventional restrain model. The mRNA expression of GLO-1 was analyzed by real time RT-PCR. Moreover, the GLO-1 protein expression was also examined by immunohistochemistry in whole brain and mean density was calculated. The mRNA and protein expressions were found to be increased in animals given anxiety as compared to the normal control. Whereas, the expressions were decreased in the animals treated with eugenol and its liposome-based nanocarriers in a dose dependent manner. However, the results were better in animals treated with nanocarriers as compared to the compound alone. It is concluded that the eugenol and its liposome-based nanocarriers exert anxiolytic activity by down-regulating GLO-1 protein expression in mice.

The Impact of Acute Stress Physiology on Skilled Motor Performance: Implications for Policing

Investigations of police performance during acutely stressful situations have primarily focused on higher-order cognitive processes like attention, affect or emotion and decision-making, and the behavioral outcomes of these processes, such as errors in lethal force. However, behavioral outcomes in policing must be understood as a combination of both higher-order processes and the physical execution of motor skills. What is missing from extant police literature is an understanding of how physiological responses to acute stress contribute to observed decrements in skilled motor performance at the neuromuscular level. The purpose of the current paper is to fill this knowledge gap in the following ways: (1) review scientific evidence for the physiological (i.e., autonomic, endocrine, and musculoskeletal) responses to acutely stressful exposures and their influence on skilled motor performance in both human and animal models, (2) review applied evidence on occupationally relevant stress physiology and observed motor decrements in performance among police, and (3) discuss the implications of stress physiology for police training and identify future directions for applied researchers. Evidence is compelling that skill decay is inevitable under high levels of acute stress; however, robust evidence-informed training practices can help mitigate this decay and contribute to officer safety.

Preliminary study on the mechanism underlying the interaction of balance dysfunction and anxiety disorder

This study aims to explore the anxiety-related behavioral changes and the concentration alterations of monoamine neurotransmitters in balance/anxiety-related nuclei of intratympanic gentamicin (GT)-induced balance disorder models. GT was administrated intratympanically in the adult male Sprague-Dawley rats to establish the vestibular impaired animal model. Rotarod was applied to test the vestibular function, and elevated plus maze and open field test were harnessed to evaluate the anxiety level. Monoamines and their metabolites were assayed by high-performance liquid chromatography. Rotarod test revealed that 6 days after GT administration, the average latency decreased significantly compared with the control group. Three days after GT administration, the travel distance and the central zone time obtained from open field and the duration of open arm stay and the times of open arm entries from elevated plus maze were apparently lower than those of the control group, whereas no significant differences were noted between 2-week group and the control group. Three days after GT administration, the concentration of norepinephrine (NE) and 5-hydroxyindoleacetic acid (5-HIAA) within medial vestibular nucleus (MVN); the concentration of NE, serotonin (5-HT), and 5-HIAA within locus coeruleus (LC); and the concentration of NE, 5-HT, 5-HIAA, and 3,4-dihydroxyphenylacetic acid within dorsal raphe nucleus (DRN) increased significantly compared with the control group. Two weeks after the administration, the concentrations of part of the neurotransmitters were lower than those of the 3-day group, indicating the rapid activation and slow deactivation of MVN-LC and MVN-DRN pathways. Vestibular impairment could lead to elevated anxiety level. The elevated anxiety levels might be attributed to increased monoamine concentrations within MVN, LC, and DRN.

New Insights on Emotional Contributions to Human Postural Control

It has been just over 20 years since the effects of height-induced threat on human postural control were first investigated. Raising the height of the support surface on which individuals stood increased the perceived consequences of instability and generated postural control changes. Since this initial work, converging evidence has accumulated supporting the efficacy of using height-induced threat to study the effects of emotions on postural control and confirming a direct influence of threat-related changes in arousal, anxiety, and fear of falling on all aspects of postural control, including standing, anticipatory, and reactive balance. In general, threat-related postural changes promote a greater physical safety margin while maintaining upright stance. We use the static balance literature to critically examine the current state of knowledge regarding: (1) the extent to which threat-related changes in postural control are sensitive to threat-related changes in emotions; (2) the underlying neurophysiological and cognitive mechanisms that may contribute to explaining the relationship between emotions and postural control; and (3) the generalizability of threat-related changes across different populations and types of threat. These findings have important implications for understanding the neuromechanisms that control healthy balance, and highlight the need to recognize the potential contributions of psychological and physiological factors to balance deficits associated with age or pathology. We conclude with a discussion of the practical significance of this research, its impact on improving diagnosis and treatment of postural control deficits, and potential directions for future research.

Protective immunity induced by an intranasal multivalent vaccine comprising 10 Lactococcus lactis strains expressing highly prevalent M-protein antigens derived from Group A Streptococcus

Streptococcus pyogenes (group A Streptococcus) causes diseases ranging from mild pharyngitis to severe invasive infections. The N-terminal fragment of streptococcal M protein elicits protective antibodies and is an attractive vaccine target. However, this N- terminal fragment is hypervariable: there are more than 200 different M types. In this study, an intranasal live bacterial vaccine comprising 10 strains of Lactococcus lactis, each expressing one N-terminal fragment of M protein, has been developed. Live bacterial-vectored vaccines cost less to manufacture because the processes involved are less complex than those required for production of protein subunit vaccines. Moreover, intranasal administration does not require syringes or specialized personnel. Evaluation of individual vaccine types (M1, M2, M3, M4, M6, M9, M12, M22, M28 and M77) showed that most of them protected mice against challenge with virulent S. pyogenes. All 10 strains combined in a 10-valent vaccine (M×10) induced serum and bronchoalveolar lavage IgG titers that ranged from three- to 10-fold those of unimmunized mice. After intranasal challenge with M28 streptococci, survival of M×10-immunized mice was significantly higher than that of unimmunized mice. In contrast, when mice were challenged with M75 streptococci, survival of M×10-immunized mice did not differ significantly from that of unimmunized mice. Mx-10 immunized mice had significantly less S. pyogenes in oropharyngeal washes and developed less severe disease symptoms after challenge than did unimmunized mice. Our L. lactis-based vaccine may provide an alternative solution to development of broadly protective group A streptococcal vaccines.

Behavioural characterization of C57BL/6N and BALB/c female mice in social home cage - Effect of mixed housing in complex environment

Developing reliable mouse models for social behaviour is challenging. Different tests have been proposed, but most of them consist of rather artificial confrontations of unfamiliar mice in novel arenas or are relying on social stress induced by aggressive conspecifics. Natural social interaction in home cage in laboratory has not been investigated well. IntelliCage is a fully automated home-cage system, where activity of the group-housed mice can be monitored along with various cognitive tasks. Here we report the behavioural profile of C57BL/6N (B6) and BALB/c (BALB) female mice in IntelliCage when separated by strain, followed by monitoring of activity and formation of 'home-base' after mixing two strains. For that purpose, 3 cages were connected. Significant differences between the strains were established in baseline behaviour in conventional tests and in IntelliCage. The B6 mice showed reduced anxiety-like behaviour in open field and light-dark box, slightly enhanced exploratory activity in IntelliCage during initial adaptation and clearly distinct circadian activity. Mixing of two strains resulted in reduction of body weight and anhedonia in B6 mice. In addition, the B6 mice showed clear preference to previous home-cage, and formed a new home-base faster than BALB mice. In contrast, BALB mice showed enhanced activity and moving between the cages without showing any preference to previous home-cage. It could be argued that social challenge caused changes in both strains and different coping styles are responsible for behavioural manifestations. Altogether, this approach could be useful in modelling and validating mouse models for disorders with disturbed social behaviour.

Neuroticism modulates brain visuo-vestibular and anxiety systems during a virtual rollercoaster task

Different lines of research suggest that anxiety‐related personality traits may influence the visual and vestibular control of balance, although the brain mechanisms underlying this effect remain unclear. To our knowledge, this is the first functional magnetic resonance imaging (fMRI) study that investigates how individual differences in neuroticism and introversion, two key personality traits linked to anxiety, modulate brain regional responses and functional connectivity patterns during a fMRI task simulating self‐motion. Twenty‐four healthy individuals with variable levels of neuroticism and introversion underwent fMRI while performing a virtual reality rollercoaster task that included two main types of trials: (1) trials simulating downward or upward self‐motion (vertical motion), and (2) trials simulating self‐motion in horizontal planes (horizontal motion). Regional brain activity and functional connectivity patterns when comparing vertical versus horizontal motion trials were correlated with personality traits of the Five Factor Model (i.e., neuroticism, extraversion‐introversion, openness, agreeableness, and conscientiousness). When comparing vertical to horizontal motion trials, we found a positive correlation between neuroticism scores and regional activity in the left parieto‐insular vestibular cortex (PIVC). For the same contrast, increased functional connectivity between the left PIVC and right amygdala was also detected as a function of higher neuroticism scores. Together, these findings provide new evidence that individual differences in personality traits linked to anxiety are significantly associated with changes in the activity and functional connectivity patterns within visuo‐vestibular and anxiety‐related systems during simulated vertical self‐motion. Hum Brain Mapp 38:715–726, 2017. © 2016 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc.

Functional and psychiatric vestibular disorders

Behavioral factors have long been recognized as affecting spatial orientation and balance function. Neuroanatomic and neurophysiologic studies conducted worldwide over the last 30 years have substantially advanced our knowledge about the inherently strong connectivity among threat/anxiety, vestibular, visual, and somatosensory systems in the brain. Clinical investigations have shed greater light on the nature of functional and psychiatric disorders that manifest or magnify vestibular morbidity. Concepts of these syndromes have changed over 150 years. Even their nomenclature has had different meanings in different eras. This chapter will review functional and psychiatric vestibular disorders. Terminology will follow the International Classification of Diseases, 11th edition, beta draft and the International Classification of Vestibular Disorders. Anxiety plays a central role in behavioral vestibular morbidity. Anxiety, traumatic stress, obsessive, and depressive disorders may be primary causes of episodic and chronic vestibular symptoms or secondary complications of other vestibular disorders. These psychiatric illnesses affect 30-50% of patients who consult neurologists or otologists for vestibular symptoms. Coexisting psychiatric disorders adversely affect treatment for patients with structural vestibular diseases, especially when unrecognized. Persistent postural-perceptual dizziness is the leading cause of long-term vestibular disability. Fortunately, pharmacologic, psychotherapeutic, and rehabilitative treatments of these illnesses have improved in recent years.

Modulation of human vestibular reflexes with increased postural threat

Anxiety and arousal have been shown to facilitate human vestibulo-ocular reflexes, presumably through direct neural connections between the vestibular nuclei and emotional processing areas of the brain. However, the effects of anxiety, fear and arousal on balance-relevant vestibular reflexes are currently unknown. The purpose of this study was to manipulate standing height to determine whether anxiety and fear can modulate the direct relationship between vestibular signals and balance reflexes during stance. Stochastic vestibular stimulation (SVS; 2-25 Hz) was used to evoke ground reaction forces (GRF) while subjects stood in both LOW and HIGH surface height conditions. Two separate experiments were conducted to investigate the SVS-GRF relationship, in terms of coupling (coherence and cumulant density) and gain, in the medio-lateral (ML) and antero-posterior (AP) directions. The short- and medium-latency cumulant density peaks were both significantly increased in the ML and AP directions when standing in HIGH, compared to LOW, conditions. Likewise, coherence was statistically greater between 4.3 Hz and 6.7 Hz in the ML, and between 5.5 and 17.7 Hz in the AP direction. When standing in the HIGH condition, the gain of the SVS-GRF relationship was increased 81% in the ML direction, and 231% in the AP direction. The significant increases in coupling and gain observed in both experiments demonstrate that vestibular-evoked balance responses are augmented in states of height-induced postural threat. These data support the possibility that fear or anxiety-mediated changes to balance control are affected by altered central processing of vestibular information.

Towards a postural indicator of back pain in horses (Equus caballus)

Postures have long been used and proved useful to describe animals' behaviours and emotional states, but remains difficult to assess objectively in field conditions. A recent study performed on horses using geometric morphometrics revealed important postural differences between 2 horse populations differing in management conditions (leisure horses living in social groups used for occasional "relaxed" riding/riding school horses living in individual boxes used in daily riding lessons with more constraining techniques). It was suggested that these postural differences may reflect chronic effects of riding techniques on the horses' kinematics and muscular development. In the present study, we tried to evaluate the interest of postural measures to assess welfare in horses. This study was separated into 2 parts. First, 18 horses coming from these 2 types of populations (leisure/riding school horses) were submitted to 2 back evaluations by 1) manual examination (experienced practitioner) and 2) sEMG measures along the spine. We then measured neck roundness on 16 of these 18 horses. The results highlighted high correlations between manual and sEMG examinations over the spine. sEMG measures at the different locations were strongly correlated all over the spine. Moreover, neck postures and muscular activities were strongly correlated, horses with concave necks having higher sEMG measures both at precise locations (i.e. cervical sites) but also when comparing neck postures to the whole spine muscular activity highlighting the functioning of horses' back as a whole. Lastly, strong differences appeared between the populations, leisure horses being evaluated as having sounder spines, exhibiting lower sEMG measures and rounder neck than the riding school horses. sEMG measures and neck "roundness" seemed therefore to be reliable indicators of back disorders, easy to evaluate in field conditions. This highlights the accuracy of using postural elements to evaluate the animals' general state and has important implications for animals' welfare evaluations.

Performance in anxiety and spatial memory tests following bilateral vestibular loss in the rat and effects of anxiolytic and anxiogenic drugs

Vestibular dysfunction in humans is associated with anxiety and cognitive disorders. However, various animal studies of the effects of vestibular loss have yielded conflicting results, from reduced anxiety to increased anxiety, depending on the particular model of vestibular dysfunction and the anxiety test used. In this study we revisited the question of whether rats with surgical bilateral vestibular deafferentation (BVD) exhibit changes in anxiety-related behaviour by testing them in the open field maze (OFM), elevated plus maze (EPM) and elevated T maze (ETM) in the presence of a non-sedating anxiolytic drug, buspirone, or an anxiogenic drug, FG-7142. We also tested the animals in a spatial T maze (STM) in order to evaluate their cognitive function under the same set of conditions. We found that BVD animals exhibited increased locomotor activity (P≤0.003), reduced supported and unsupported rearing (P≤0.02 and P≤0.000, respectively) and reduced thigmotaxis (P≤0.000) in the OFM, which for the most part the drugs did not modify. By contrast, there were no significant differences between BVD and sham control animals in the EPM and the BVD animals exhibited a marginally longer escape latency in the ETM (P≤0.03), with no change in avoidance latency. In the STM, the BVD animals demonstrated a large and significant decrease in accuracy compared to the sham control animals (P≤0.000), which was not affected by drug treatment. These results have replicated previous findings regarding increased locomotor activity, reduced rearing and thigmotaxis in the OFM, and impaired performance in the STM. However, they failed to replicate some previous results obtained using the EPM and ETM. Overall, they do not support the hypothesis that BVD animals exhibit increased anxiety-like behaviour and suggest that the cognitive deficits may be independent of the emotional effects of vestibular loss.

Behavioral models for anxiety and multisensory integration in animals and humans

Complaints related to dizziness, balance problems and spatial disorientation in psychiatry have seldom been considered as a possible manifestation of a distorted multisensory integrative ability. Several kinds of mismatches among simultaneous sensory information are encountered in everyday life but despite these, the central nervous system usually manages to update the internal representation of the body in the surrounding space. In some cases, a sensory mismatch may elicit an erroneous perception of the body in space, resulting in anxiety, dizziness and balance problems. As vestibular system dysfunction leads to dizziness and disorientation, it has been hypothesized that a peripheral vestibular abnormality could explain the presence of certain symptoms related to sensory mismatches in anxiety disorders. Several studies tried to find a link between panic disorder with or without agoraphobia and vestibular system dysfunction. Yet, even though some vestibular abnormalities have been demonstrated in these patients, it is difficult to demonstrate a cause-and-effect relationship between panic disorder and vestibular dysfunction. However, this does not rule out a possible influence of anxiety on normal vestibular function. The study of the relation between vestibular system and anxiety has to take into account that the vestibular system has three main functions: to maintain equilibrium through the vestibular spinal reflexes; to stabilize the visualization of the world through the vestibular-ocular reflex; to contribute to perception and orientation in space. We will review different studies in humans, which have particularly paid attention to the third function and its relation to anxiety. Animal experiments offer possibilities to more precisely analyze the different parameters underlying the behavioral results, as well as possible pharmacological actions on them. Two attempts have been made by our group to model, in mice, the preceding human data on integrated functional sensory relations of the body to space in anxiety disorders: the rotating beam and the rotating tunnel. We summarize here the main results obtained.

The effect of three different items of cage furniture on the behaviour of male C57BL/6J mice in the plus-maze test

The aim of this study was to assess the effects of specific regimens of enrichment on the behaviour of C57BL/6J mice in the elevated plus-maze test (EPM). A total of 192 male C57BL/6J mice were allocated randomly to 32 cages. Three different items of cage furniture (CF) made of aspen — a mouse corner, nestbox and stairs — were added stepwise to different cages at intervals of one week so that the mice were exposed to an item of CF for one, two, three or four weeks. On the fifth week, all the mice were subjected to the EPM test. Overall, the presence of the nestbox or stairs for the three weeks appeared to have an anxiolytic effect on the behaviour of the mice, as evidenced by an increase in the number of entries made into the open arms and the time spent in the open arms of the EPM. The effects of these items of CF on the behaviour of the mice depended on the item used and on the duration of exposure. The items of CF that were used in this study appeared to improve the quality of life of C57BL/6J mice, as assessed using the EPM.

Pharmacological, neurochemical, and behavioral profile of JB-788, a new 5-HT1A agonist

A novel pyridine derivative, 8-{4-[(6-methoxy-2,3-dihydro-[1,4]dioxino[2,3-b]pyridine-3-ylmethyl)-amino]-butyl}-8-aza-spiro[4.5]decane-7,9-dione hydrochloride, termed JB-788, was designed to selectively target 5-HT(1A) receptors. In the present study, the pharmacological profile of JB-788 was characterized in vitro using radioligands binding tests and in vivo using neurochemical and behavioural experiments. JB-788 bound tightly to human 5-HT(1A) receptor expressed in human embryonic kidney 293 (HEK-293) cells with a K(i) value of 0.8 nM. Its binding affinity is in the same range as that observed for the (+/-)8-OH-DPAT, a reference 5HT(1A) agonist compound. Notably, JB-788 only bound weakly to 5-HT(1B) or 5-HT(2A) receptors and moreover the drug displayed only weak or indetectable binding to muscarinic, alpha(2), beta(1) and beta(2) adrenergic receptors, or dopaminergic D(1) receptors. JB-788 was found to display substantial binding affinity for dopaminergic D(2) receptors and, to a lesser extend to alpha(1) adrenoreceptors. JB-788 dose-dependently decreased forskolin-induced cAMP accumulation in HEK cells expressing human 5-HT(1A), thus acting as a potent 5-HT(1A) receptor agonist (E(max.) 75%, EC(50) 3.5 nM). JB-788 did not exhibit any D(2) receptor agonism but progressively inhibited the effects of quinpirole, a D(2) receptor agonist, in the cAMP accumulation test with a K(i) value of 250 nM. JB-788 induced a weak change in cAMP levels in mouse brain but, like some antipsychotics, transiently increased glycogen contents in various brain regions. Behavioral effects were investigated in mice using the elevated plus-maze. JB-788 was found to increase the time duration spent by animals in anxiogenic situations. Locomotor hyperactivity induced by methamphetamine in mouse, a model of antipsychotic activity, was dose-dependently inhibited by JB-788. Altogether, these results suggest that JB-788 displays pharmacological properties, which could be of interest in the area of anxiolytic and antipsychotic drugs.

Effects of bilateral vestibular deafferentation on anxiety-related behaviours in Wistar rats

Despite frequent reports that patients with vestibular dysfunction exhibit an unusually high incidence of anxiety disorders, few studies have investigated the emotional effects of vestibular damage in animals. In this study we investigated the effects of a permanent surgical bilateral vestibular deafferentation (BVD) on the performance of rats in a series of anxiety tests at 3 weeks (3-W), 3 months (3-M) and 5 months (5-M) following the lesion. We used the elevated plus maze (EPM), elevated T maze (ETM), hyponeophagia and social interaction tests. Contrary to expectation, we found that, at 3 and 5M post-op, BVD rats spent more rather than less time on the open arms of the EPM compared to sham controls, and they displayed a lack of learned inhibitory avoidance in the ETM. Compared to sham controls, BVD rats showed no significant difference over the 3 time points in their latencies to eat in a novel situation; however, they did engage in social interaction to a significantly lesser extent. Finally, blood corticosterone levels were not significantly different between BVD and sham rats at 6 months post-op. These results suggest that BVD causes changes in the performance of rats in the EPM and ETM that might reflect emotional changes, or could be due to the cognitive impairment and hyperactivity caused by BVD.

Exaggerated emotional behavior in mice heterozygous null for the sodium channel Scn8a (Nav1.6)

The Scn8a gene encodes the alpha-subunit of Na(v)1.6, a neuronal voltage-gated sodium channel. Mice homozygous for mutations in the Scn8a gene exhibit motor impairments. Recently, we described a human family with a heterozygous protein truncation mutation in SCN8A. Rather than motor impairment, neuropsychological abnormalities were more common, suggesting a role for Scn8a in a more diverse range of behaviors. Here, we characterize mice heterozygous for a null mutation of Scn8a (Scn8a(+/-)mice) in a number of behavioral paradigms. We show that Scn8a(+/-)mice exhibit greater conditioned freezing in the Pavlovian fear conditioning paradigm but no apparent abnormalities in other learning and memory paradigms including the Morris water maze and conditioned taste avoidance paradigm. Furthermore, we find that Scn8a(+/-)mice exhibit more pronounced avoidance of well-lit, open environments as well as more stress-induced coping behavior. Together, these data suggest that Scn8a plays a critical role in emotional behavior in mice. Although the behavioral phenotype observed in the Scn8a(+/-)mice only partially models the abnormalities in the human family, we anticipate that the Scn8a(+/-)mice will serve as a valuable tool for understanding the biological basis of emotion and the human diseases in which abnormal emotional behavior is a primary component.

The regular and light-dark Suok tests of anxiety and sensorimotor integration: utility for behavioral characterization in laboratory rodents

Animal behavioral models are crucial for neurobiological research, allowing for the thorough investigation of brain pathogenesis to be performed. In both animals and humans, anxiety has long been linked to vestibular disorders. However, although there are many tests of anxiety and vestibular deficits, there are few protocols that address the interplay between these two domains. The Suok test and its light-dark modification presented here appear to be suitable for testing this pathogenetic link in laboratory rodents. This protocol adds a new dimension to previously used tests by assessing animal anxiety and balancing simultaneously, resulting in efficient, high-throughput screens for testing psychotropic drugs, phenotyping genetically modified animals, and modeling clusters of human disorders related to stress/anxiety and balancing.

Anxiety and otovestibular disorders: linking behavioral phenotypes in men and mice

Human anxiety and vestibular disorders have long been known to co-occur. Paralleling human clinical and non-clinical data, mounting genetic, pharmacological and behavioral evidence confirms that animal anxiety interplays and co-exists with vestibular/balance deficits. However, relatively few animal models have addressed the nature of this relationship. This paper examines side-by-side human psychiatric and otovestibular phenotypes with animal experimentation data, and outlines future directions of translational research in this field. Discussed here are recently developed specific animal models targeting this interplay, other traditional animal tests sensitive to altered anxiety and vestibular domains, and the existing problems with translation of animal data into human phenotypes. The role of hearing deficits and their contribution to anxiety and vestibular phenotypes are also outlined. Overall, the overlap between anxiety and balance disorders emerges as an important phenomenon in both animal and clinical studies, and may contribute markedly to the complexity of behavioral and physiological phenotypes. Animal experimental models that focus on the interplay between anxiety and vestibular disorders are needed to improve our understanding of this important biomedical problem.

Pharmacological modulation of anxiety-related behaviors in the murine Suok test

We have recently introduced a new model of anxiety--the Suok test and its light-dark modification--for behavioral characterization in mice and rats, including simultaneous assessment of their anxiety, activity, and neurological phenotypes. In the present study, testing different inbred (129S1, BALB/c) and hybrid (C57-129S1) mouse strains in both Suok test modifications, we examined the effects on anxiety-related behaviours produced by traditional anxiogenic and anxiolytic drugs. Here we show dose-dependent increases in anxiety-related behaviors produced by anxiogenic drug pentylenetetrazole (10 and 20 mg/kg). In contrast, anxiolytic drugs ethanol (0.75 and 1.5 g/kg) and diazepam (0.5 mg/kg) reduced anxiety and increased mouse exploration in this test. Hyperemotional anxious BALB/c mice were particularly sensitive to pharmacogenic anxiety in Suok test, also showing robust light-dark shifts in the light-dark version of this test. Overall, the results of this study confirm the potential utility of both murine Suok tests, especially when used in selected "sensitive" mouse strains, for high-throughput screening of potential anxiotropic drugs.

What's wrong with my mouse model?

Stress plays a key role in pathogenesis of anxiety and depression. Animal models of these disorders are widely used in behavioral neuroscience to explore stress-evoked brain abnormalities, screen anxiolytic/antidepressant drugs and establish behavioral phenotypes of gene-targeted or transgenic animals. Here we discuss the current situation with these experimental models, and critically evaluate the state of the art in this field. Noting a deficit of fresh ideas and especially new paradigms for animal anxiety and depression models, we review existing challenges and outline important directions for further research in this field.

Modulation of motor function by stress: a novel concept of the effects of stress and corticosterone on behavior

Stress and stress hormones affect a variety of behaviors and cognitive abilities. The influences of stress and glucocorticoids on motor function, however, have not been characterized although the presence of glucocorticoid receptors in the motor system has been documented. Here we demonstrate that stress and the stress hormone corticosterone influence motor system function in rats. Groups of adult female Long-Evans rats underwent either a daily stress-inducing procedure (immobilization or swimming in cold water) or oral corticosterone treatment. While these treatments continued, animals were tested in skilled reaching and skilled walking tasks for a period of 2 weeks. Both acute (day 1) and chronic (day 14) stress and corticosterone treatment reduced skilled movement accuracy in reaching and walking and increased performance speed. Furthermore, both chronic stress and chronic corticosterone treatment altered skilled movement patterns in the reaching task. These findings indicate that stress modulates motor system function and that these effects are partially mediated by glucocorticoids. To examine whether stress-induced changes might also derive from enhanced emotionality, rats were treated with the benzodiazepine diazepam. Based on an inverted U-shaped dose-response relationship, a moderate dose of diazepam significantly improved reaching success while at the same time reducing corticosterone levels. Thus, stress-associated emotional responses such as anxiety might account for diminished movement accuracy. These results suggest that stress affects the motor system both directly via hormonal changes and indirectly via changes in emotionality. These findings are discussed with respect to the role of stress in motor system function and movement disorders.

Age-related changes in postural responses to externally- and self-triggered continuous perturbations

This is a cross sectional study of eight healthy young (age 22+/-2 years) and eight healthy older (age 70+/-5 years) adults who participated in an experiment in which they had to keep their balance while standing on a platform moving in the anterior/posterior direction. The 20 cm peak-to-peak platform movements were sinusoidal at increasing frequencies up to 0.61 Hz. The frequency increases were either sudden and unpredictable (externally-triggered perturbations) or controlled by the subjects themselves (self-triggered perturbations). To maintain balance, all subjects used anticipatory adjustments such as early postural muscle activation, leading to fewer steps being taken, tighter coupling of the center of pressure (COP) and the platform movements, and small COP excursions. These adjustments were found to be lacking for externally-triggered perturbations in older subjects; in these subjects the COP range was larger and more often in less safe regions at the boundaries of the base of support.

The Suok ("ropewalking") murine test of anxiety

In the present study, we suggest that long elevated horizontal rod (Suok test, ST) and its light-dark modification (LDST) may be used for behavioral characterization in mice, including simultaneous assessment of their anxiety, activity, and neurological phenotypes. To establish the ST and the LDST as murine models of anxiety, we used several different mouse strains which differ markedly in their anxiety and activity (C57BL/6, 129S1/SvImJ, NMRI, and BALB/c). Here we show that our tests are able to ethologically discriminate between high and low anxiety mouse strains, as assessed by horizontal and directed exploration, stops, and defecation boli. The spatial distribution of the LDST behaviors is also sensitive to these strain-specific anxiety phenotypes, showing clear avoidance of the brightly lit part of the test in stressed (rat exposed) vs. control NMRI mice. In addition, we validated the ST in 129S1/SvImJ and BALB/c mice by assessing the behavioral consequences of acute stress such as rat exposure. Finally, we showed that our test is able to detect high anxiety and poorer motor coordination in 129S1/SvImJ (vs. C57BL/6) mice. The results of our study show that the ST emerges as an experimental tool to analyze anxiety, motor-vestibular anomalies, as well as anxiety-induced motor impairments in mice. Overall, we suggest that the ST can be a useful protocol in neurobehavioral stress research including modeling stress-evoked states, pharmacological screening of potential anti-stress drugs, or behavioral phenotyping of genetically modified animals.

Chronic ultra-mild stress improves locomotor performance of B6D2F1 mice in a motor risk situation

Chronic low grade stress predispose to psychopathological disorders. We consistently showed that chronic ultra-mild stress (CUMS) applied to B6D2F1 female mice induced behavioral disinhibition in several conflict exploration models. Insufficient reactivity to conflicts may be maladaptive and lead to inappropriate appreciation of potential risks and impaired ability to cope with those. Therefore, the purpose of the study was to assess the effect of a CUMS procedure on the behavior of mice in a motor risk situation based on multisensory conflict. Following three weeks exposure to various mild stressors, stressed and control B6D2F1 mice were tested on the rotating beam to determine how CUMS exposure affected balance control, posture stability and locomotor performance in response to a sensory-motor challenge. Detailed behavioral analysis included several parameters, both postural (height of the trunk, tail angle, number of imbalances, falls and head movements) and kinetic (mean velocity on the beam, distance covered with large and small movements, plus time spent in no-motion episodes). Comparisons between control and stressed mice showed that CUMS exposure increased mean velocity and improved locomotor performance in the learning task. In addition, sensitivity to sensory conflict seemed to be reduced in stressed mice, which displayed fewer behavioral adjustments to the increasing difficulty of the test compared to control mice. The results are discussed in terms of the possible influence of disturbances in behavioral and attentional inhibitory processes following CUMS exposure. Whether longer periods of CUMS exposure would shift the performance on the RTB from improvement to deterioration remain to be established.

A new method for the assessment of spatial orientation and spatial anxiety in mice

The implication of integrated functional sensory relations of the body to space in anxiety disorders is a very important issue which encourages the development of animal models, in particular, for pharmacological perspectives and for the functional assessment of the deficits induced by genetic manipulation in the mouse or the rat. A new experimental device is presented here: It is comprised of a rotating tunnel and a rotating-beam controlled by computer which can be used for multiple visuo-idiothetic and kinesthetic sensory conflict situations during active locomotor behaviour by mice. The system is linked to a digital video system, Video-Track trade mark, designed to track and record the movements of the animals. Anxious BALB/cByJ mice were compared to non-anxious C57BL/6J mice and were seen to display highly disturbed locomotor behaviour in a sensory conflict situation. The model highlights the advantages of video-digital analysis for animal behavioural sciences.

Paroxetine, a Selective Serotonin Reuptake Inhibitor, Reduces Depressive Symptoms and Subjective Handicaps in Patients with Dizziness

OBJECTIVE AND STUDY DESIGN

When treating dizzy patients, the psychiatric aspect should be carefully addressed regardless of whether a well-defined organic disease is present. In this prospective study, we aimed to elucidate the role of paroxetine, a selective serotonin reuptake inhibitor, in the treatment of dizziness.

SETTING AND PATIENTS

Forty-seven patients who complained of dizziness were treated with 20 mg of paroxetine per day. The depressive state of the patient was evaluated by the Zung Self-Rating Depression Scale (SDS). Treatment outcomes were measured with self-assessment of subjective handicaps in daily life using a dizziness and unsteadiness questionnaire. The questionnaire consisted of five factors related to emotional or bodily dysfunction that could be affected by dizziness. Changes in Self-Rating Depression Scale scores and subjective handicaps were assessed at 4 and 8 weeks after the start of paroxetine.

RESULTS

In patients having well-defined organic diseases with high Self-Rating Depression Scale scores, paroxetine improved all five subjective handicap factors as well as Self-Rating Depression Scale scores. The decline in Self-Rating Depression Scale scores showed a significant correlation with improvement of subjective handicaps, which was related to emotional problems but not factors related to bodily dysfunction. Paroxetine was also effective for an improvement of factors related to emotional problems and Self-Rating Depression Scale scores in patients not having organic diseases but with high Self-Rating Depression Scale scores. In patients either with or without organic diseases with low Self-Rating Depression Scale scores, paroxetine had no effect on any subjective handicap factors and Self-Rating Depression Scale scores.

CONCLUSION

In the treatment of dizzy patients, paroxetine was effective at relieving subjective handicaps caused by dizziness, specifically, in patients with high Self-Rating Depression Scale scores.

Swim posture of mice does not affect performance in the water maze

We quantified swim postures of mice in relation to their cognitive performance. After training in a water maze, young (5-6 months) and aged (14-16 months) female apolipoprotein E-knockout (apoE0/0) mice and wild type controls were video taped while swimming. Subsequently, angles of body points with the water surface were calculated. Mice with a more horizontal swim posture (young and aged apoE0/0, aged wild type mice) also showed an increased body weight. However, swim posture was not related to cognitive performance.

Darting behavior: a quantitative movement pattern designed for discrimination and replicability in mouse locomotor behavior

In the open-field behavior of rodents, Software for Exploring Exploration (SEE) can be used for an explicit design of behavioral endpoints with high genotype discrimination and replicability across laboratories. This ability is demonstrated here in the development of a measure for darting behavior. The behavior of two common mouse inbred strains, C57BL/6J (B6) and DBA/2J (D2), was analyzed across three different laboratories, and under the effect of cocaine or amphetamine. "Darting" was defined as having higher acceleration during progression segments while moving less during stops. D2 mice darted significantly more than B6 mice in each laboratory, despite being significantly less active. These differences were maintained following cocaine administration (up to 20mg/kg) and only slightly altered by amphetamine (up to 5mg/kg) despite a several fold increase in activity. The replicability of darting behavior was confirmed in additional experiments distinct from those used for its design. The strategy leading to the darting measure may be used to develop additional discriminative and replicable endpoints of open-field behavior.

Fear of falling and postural control in Parkinson's disease

This study investigated the relationship between fear of falling (FOF) and qualitative and quantitative postural control in Parkinson's disease (PD). Fifty-eight nondemented PD patients were studied along with age-matched healthy controls. The degree of FOF was estimated using the Activities-specific Balance Confidence scale. Qualitative postural control was evaluated using a component of the Unified Parkinson Disease Rating Scale. Postural control was quantified, using centre of pressure measures obtained from a force plate, for eight standing balance tests of different challenges. The results showed that FOF was more evident for PD patients when compared with healthy individuals of similar age. Furthermore, FOF was significantly associated with a qualitative estimate of postural control in PD; individuals with PD who had a greater degree of posture impairment reported greater FOF. The results also showed that an estimate of FOF may help to explain quantitative postural instability in PD. FOF, when coupled with a qualitative estimate of postural control, was able to explain a greater amount of variation in quantitative balance performance for five of the eight balance tests. When considered independently, the qualitative measure of postural control, in general, could not well predict quantitative balance performance. The greater degree of FOF and its possible association with altered postural control suggests that FOF should be considered as an important, independent risk factor in the assessment and treatment of postural instability in patients with PD.

Wheel running behavior is impaired by both surgical section and genetic absence of the mouse corpus callosum

Mice lacking a corpus callosum (CC) often show little or no deficit on tests of behavior. This paper reports that on highly complex bimanual motor tasks, deficits can be found. The speed of running on a wheel with irregularly spaced rungs is reduced by both hereditary absence of the CC in 129 x BALB/c recombinant mice and surgical section of the CC in genetically normal B6D2F(2) mice. The effect of CC absence appears on measures most closely related to speed, no influence exists on the amount of running over a period of 5 days. Motor behavior on a notched balance beam, on the other hand, shows clear superiority of the hybrid mice but no relation with reduced size of the CC, whether it was produced by genotype or surgery. The effect of absent CC is task dependent, but it is not obscured by developmental compensation in the recombinant mice.

Balance control and posture in anxious mice improved by SSRI treatment

A task requiring dynamic postural stabilisation during locomotion in a conflicting visual vestibular environment (rotating beam), has been devised to assess anxiety-related balance impairments and postural changes in mice. The model, already validated with acutely administered diazepam, was used to assess the action of two chronically administered selective serotonin reuptake inhibitors (SSRIs), fluoxetine and paroxetine. On three behavioural measures (imbalance, elevation of trunk and angle of tail), observed in anxious BALB/cByJ mice, both compounds had the same diazepam-like effects: reduction in number of imbalances, higher elevation of trunk and increase in tail angle. These data suggest, for the first time, that SSRIs should be useful in the treatment of anxiety-induced balance impairments.

SEE: a tool for the visualization and analysis of rodent exploratory behavior

The complexity of exploratory behavior creates a need for a visualization and analysis tool that will highlight regularities and help generating new hypotheses about the structure of this behavior. The hypotheses can then be formulated as algorithms that capture the patterns and quantify them. SEE is a Mathematica based software developed by us for the exploration of exploratory behavior. The raw data for SEE are a time series of the animal 's coordinates in space sampled at a rate that allows a meaningful computation of speeds. SEE permits: (i) a visualization of the path of the animal and a computation of the dynamics of activity; (ii) a decomposition of the path into several modes of motion (1st gear, 2nd gear, etc.) and a computation of the typical maximal speeds, the spatial spread, and the proportion of each of these modes; and(iii) a visualization of the location in the environment of stopping episodes, along with their dwell time. These visualizations highlight the presence of preferred places, including the animal's so-called home base, and permits a computation of the spatio-temporal diversity in the location of stopping episodes. The software also: (i) decomposes the animal's path into round trips from the home base, called 'excursions', and computes the number of stops per excursion; (ii) generates a visualization of the phase space (path+speed, traced in a three-dimensional graph) of any progression segment or list of such segments; and (iii) produces a visualization of the way places in the animal's operational world are connected to each other. SEE also permits the definition and computation of behavioral endpoints across any section of any database of raw data. The range of applicability of SEE to various experimental set ups, tracking procedures, species, and preparations is addressed in the discussion.