Passive Behavioral Strategies Research Articles

Pre-operative environmental enrichment does not yield a prophylactic effect against traumatic brain injury-induced neurobehavioral deficits

The robustness of environmental enrichment (EE) in ameliorating neurobehavioral and cognitive deficits after experimental traumatic brain injury (TBI) is unequivocal. What is equivocal is whether EE can function as a prophylactic to afford resiliency and neuroprotection against TBI. We hypothesized that pre-operative EE would yield a protective effect against TBI-induced motor, cognitive, and coping deficits, and that further improvements would be conferred when EE is provided before and after TBI. To test the hypotheses, adult male rats received either 4 weeks of EE or standard (STD) housing prior to undergoing a controlled cortical impact of moderate severity (2.8 mm deformation at 4 m/s) or sham injury while under anesthesia. After injury, the rats were randomly assigned to post-operative EE or STD housing. Motor ability, spatial learning, and memory retention were assessed by beam-walk and water maze tests, respectively. Active and passive behavioral coping strategies were evaluated with the shock probe defensive burying (SPDB) test. c-Fos and cortical lesion volume were also quantified. The post-TBI enrichment groups (EE + TBI + EE and STD + TBI + EE) did not differ (p > 0.05) and performed better than the post-TBI STD-housed groups (EE + TBI + STD and STD + TBI + STD) on motor and cognition (p < 0.05). The post-TBI STD groups did not differ, regardless of whether in EE or STD living conditions before injury (p > 0.05). Moreover, both post-TBI enrichment groups performed better in the SPDB test relative to the STD + TBI + STD group (p < 0.05). c-Fos + cells were upregulated in the ipsilateral CA1 in both pre-injury EE groups relative to the pre-injury STD groups (p < 0.05). No statistical differences were observed in cortical lesion volume among the groups. Overall, these data do not support the hypothesis as no neuroprotective effect was observed with 4 weeks of pre-operative EE and no additional benefit was achieved in the TBI group receiving both pre-and-post EE relative to the TBI group receiving only post-EE. However, the data do reinforce the consistency of post-TBI EE in producing robust neurobehavioral benefits, which further supports this paradigm as a relevant preclinical model of neurorehabilitation.

FEATURES OF COPING STRATEGIES IN MEN AND WOMEN DURING THE MARTIAL LAW

The article discusses the issue of coping behavior as a form of behavior that reflects an individual's readiness to solve life problems. What is especially relevant in times of trials from military threats in the country. This behavior is aimed at adapting to circumstances and involves the developed ability to use certain means to overcome emotional stress. When choosing active actions, the probability of eliminating the effect of stressors on a person increases. The theoretical analysis showed that coping strategies are necessary when a person gets into a crisis situation. Any crisis situation presupposes the presence of some objective circumstances and a certain attitude of a person to them, depending on the degree of their significance, which is accompanied by emotional and behavioral reactions of various nature and degree of intensity. The leading characteristics of a crisis situation are mental tension, significant experiences as a special internal work to overcome life events or traumas, a change in self-esteem and motivation, as well as a pronounced need for their correction and psychological support from the outside.&#x0D; It was found that the motivational orientation of the individual determines the features of coping strategies in crisis situations. Thus, subjects with a pronounced motivation to avoid failure are more likely to use passive behavioral strategies in stressful situations - social support and avoidance, which reflects their weak efforts in solving any problem situation. And the subjects with a high level of motivation for success mainly use the strategy of finding a solution in stressful situations, aimed at solving the problem and adequately responding to the stressful situation. It was established that almost half of the researched use the strategy of finding a solution in stressful situations. That is, they have the highest level of development of adaptive coping mechanisms, tend to analyze stressful situations and find ways to solve them, have high confidence in their own resources to overcome stressful situations. The application of practical steps aimed at solving the situation significantly increases the constructiveness and effectiveness of overcoming it.

A Moderate Duration of Stress Promotes Behavioral Adaptation and Spatial Memory in Young C57BL/6J Mice.

Stress may serve multiple roles in cerebral functioning, ranging from a highly appropriate behavioral adaptation to a critical risk factor for susceptibility to mood disorder and cognitive impairment. It is well known that E/I (excitation/inhibition) balance is essential for maintaining brain homeostasis. However, it remains largely unknown how GABAergic and Glutamatergic neurons respond to different stressful stimuli and whether the GABAergic-Glutamatergic neuron balance is related to the transition between adaptive and maladaptive behaviors. Here, we subjected 3-month-old mice to chronic mild stress (CMS) for a period of one, two, and four weeks, respectively. The results showed that the two-week CMS procedure produced adaptive effects on behaviors and cognitive performance, with a higher number of GABAergic neuron and VGluT1-positive neurons, increasing the expressions of p-GluN2B, Reelin, and syn-PSD-95 protein in the hippocampus. In contrast, the prolonged behavioral challenge (4 week) imposes a passive coping behavioral strategy and cognitive impairment, decreased the number of GABAergic neuron, hyperactivity of VGluT1-positive neuron, increased the ratio of p-GluN2B, and decreased the expression of Reelin, syn-PSD-95 in the hippocampus. These findings suggest that a moderate duration of stress probably promotes behavioral adaptation and spatial memory by maintaining a GABAergic-Glutamatergic neuron balance and promoting the expression of synaptic plasticity-related proteins in the brain.

Adaptation to Other Agent’s Behavior Using Meta-Strategy Learning by Collision Avoidance Simulation

In human’s cooperative behavior, there are two strategies: a passive behavioral strategy based on others’ behaviors and an active behavioral strategy based on the objective-first. However, it is not clear how to acquire a meta-strategy to switch those strategies. The purpose of the proposed study is to create agents with the meta-strategy and to enable complex behavioral choices with a high degree of coordination. In this study, we have experimented by using multi-agent collision avoidance simulations as an example of cooperative tasks. In the experiments, we have used reinforcement learning to obtain an active strategy and a passive strategy by rewarding the interaction with agents facing each other. Furthermore, we have examined and verified the meta-strategy in situations with opponent’s strategy switched.

Anxiety-like behavior in acute and protracted withdrawal after morphine-induced locomotor sensitization in C57BL/6 male mice: The role of context

Contextual memory plays an important role in development and maintenance of drug addiction. However, little is known about of the role contextual memory in the emergence of a negative emotional state in the withdrawal period. Therefore, this study investigated anxiety-like behavior in acute and protracted morphine withdrawal of mice submitted to a locomotor sensitization protocol and the influence of contextual memory on this behavior. Male adult C57Bl6 mice were subjected to morphine locomotor sensitization and anxiety-like behavior was assessed by using the elevated plus maze test (EPM). To evaluate associative memory, the mice were re-exposed to the context of locomotor sensitization immediately before EPM. As expected, repeated morphine administrations promoted locomotor sensitization, seen as a gradual increase in the distance traveled during the acquisition phase. There was an increase in anxiety-like behavior upon acute withdrawal, as indicated by a decrease in open arms activity (OAA), but this effect dissipated over time. However, when the context was presented, mice in protracted withdrawal showed enhanced anxiety-like behavior, indicated by an increase in closed arms activity (CAA). This effect was context specific since re-exposure in an alternative context did not change the anxiety-like behavior. Treatment with diazepam counteracted the decrease in OAA in acute withdrawal and the increase in CAA induced by context re- exposure during protracted abstinence. Thus, repeated morphine administration induced a negative emotional state when the drug was discontinued. The context associated with drug exposure played a pivotal role in the appearance of anxiety-like behavior, even long after drug discontinuation. There were differences in the patterns of anxiety behaviors in acute (unconditioned anxiety-like behavior) and protracted (conditioned anxiety-like behavior) withdrawal since the former was characterized by a passive behavioral strategy and the latter by an active behavioral strategy.

Behavior of Rats with High and Low Levels of Freezing in Defensive Situations and on Selection of Food Reinforcement

Behavior in rats with different levels of freezing in a classical defensive conditioned reflex was compared on acquisition of conditioned passive and active avoidance reflexes and on selection of food reinforcement of different values. Rats with prolonged freezing acquired the passive avoidance reflex better and retained it longer during extinction than animals with shorter freezing. At the same time, the active avoidance reflex in the shuttle box was acquired more easily by animals with short periods of freezing. Rats with prolonged freezing preferred a delayed and more valuable reinforcement in the model of choosing food reinforcements of different values (low level of impulsivity), while animals with short freezing preferred the low-value reinforcement without a delay (high level of impulsivity). The thresholds of pain sensitivity were no different in rats of the different groups. Thus, rats with prolonged freezing demonstrated a passive behavioral strategy in defensive situations and a low level of impulsivity, while rats with short freezing used an active behavioral strategy and showed a high level of impulsivity.

Anxiety and neurometabolite levels in the hippocampus and amygdala after prolonged exposure to predator-scent stress

Here, to study the relationship between anxiety levels with changes in the neurometabolic profile in the hippocampus and amygdala, an experimental predator stress model was reproduced in which Sprague-Dawley rats were exposed to cat urine for 10 minutes on a daily basis for 10 days. At the time of presentation of the stimulus, an online survey of behavioral reactions was conducted. Fear, aggressiveness, avoidance of stimulus and grooming were recorded. Fourteen days after the completion of the last stress exposure, the total level of anxiety was determined in the test of the“cross maze”. Using the method of in vivo NMR spectroscopy, the content of neurometabolites was determined in the hippocampus and in the amygdala. According to the peculiarities of behavioral reactions to a stressor, animals were retrospectively divided into two phenotypes. The first phenotype used a passive behavioral strategy, and the second phenotype was active. In animals of the first phenotype, the indicators of anxiety behavior remained at the control level. In animals of the second phenotype, a decrease in anxiety was observed. Animals of the second phenotype showed elevated levels of lactate in the hippocampus compared to animals of the first phenotype, and the lowest N-acetylaspartate levels significantly differed from those in the control and the first phenotype animals. In the amygdala, in animals of the second phenotype, the content of taurine is sharply reduced in comparison with those in the control and the animals of the first phenotype. Thus, the results obtained indicate a relationship of post-stress changes in anxiety, with the peculiarities of the behavioral reactions presented at the moment of the immediate action of the stressor. Among the hippocampal and amygdala neurometabolites, the most informative for the characterization of the anxiolytic action of the predator stress are identified.

Neuronal Dynamics Regulating Brain and Behavioral State Transitions

Prolonged behavioral challenges can cause animals to switch from active to passive coping strategies to manage effort-expenditure during stress; such normally adaptive behavioral state transitions can become maladaptive in psychiatric disorders such as depression. The underlying neuronal dynamics and brainwide interactions important for passive coping have remained unclear. Here, we develop a paradigm to study these behavioral state transitions at cellular-resolution across the entire vertebrate brain. Using brainwide imaging in zebrafish, we observed that the transition to passive coping is manifested by progressive activation of neurons in the ventral (lateral) habenula. Activation of these ventral-habenula neurons suppressed downstream neurons in the serotonergic raphe nucleus and caused behavioral passivity, whereas inhibition ofthese neurons prevented passivity. Data-driven recurrent neural network modeling pointed to altered intra-habenula interactions as a contributory mechanism. These results demonstrate ongoing encoding of experience features in the habenula, which guides recruitment of downstream networks and imposes a passive coping behavioral strategy.

The Effects of Intranasal Administration of Oxytocin on the Behavior of Rats with Different Behavioral Strategies Subjected to Chronic Mild Stress

Two groups of Wistar rats with opposite behavioral strategies – active and passive – were subjected to chronic mild stress. Half of the group of poststress animals received intranasal oxytocin (at a dose of 0.25 IU); their behavior was tested in the Porsolt test and their consumption of a sweet solution was evaluated. Stressed animals with the active behavioral strategy did not respond to oxytocin. Oxytocin partially restored behavior to prestress levels only in animals starting with the passive behavioral strategy.

Multichannel cochlear implant for selective neuronal activation and chronic use in the free-moving Mongolian gerbil

BackgroundAnimal models for chronic multichannel cochlear implant stimulation and selective neuronal activation contribute to a better understanding of auditory signal processing and central neural plasticity. New methodThis paper describes the design and surgical implantation of a multichannel cochlear implant (CI) system for chronic use in the free-moving gerbil. For chronic stimulation, adult-deafened gerbils were connected to a multichannel commutator that allowed low resistance cable rotation and stable electric connectivity to the current source. ResultsDespite the small scale of the gerbil cochlea and auditory brain regions, final electrophysiological mapping experiments revealed selective and tonotopically organized neuronal activation in the auditory cortex. Contact impedances and electrically evoked auditory brainstem responses were stable over several weeks demonstrating the long-term integrity of the implant and the efficacy of the stimulation. Comparison with existing methodsMost animal models on multichannel signal processing and stimulation-induced plasticity are limited to larger animals such as ferrets, cats and primates. Multichannel CI stimulation in the free-moving rodent and evidence for selective neuronal activation in gerbil auditory cortex have not been previously reported. ConclusionsOverall, our results show that the gerbil is a robust rodent model for selective and tonotopically organized multichannel CI stimulation. We anticipate that this model provides a useful tool to develop and test both passive stimulation and behavioral training strategies for plastic reorganization and restoration of degraded unilateral and bilateral central auditory signal processing in the hearing impaired and deaf central auditory system.

The association between sensory processing styles and mindfulness

IntroductionMindfulness is associated with psychological wellbeing and quality of life. The focus on body awareness in definitions of mindfulness suggests that an individual’s sensory processing pattern may influence mindfulness abilities. Therefore, this study seeks to examine the relationship between sensory processing styles and multiple aspects of mindfulness including components of attention, awareness, and acceptance in healthy adults.Method151 participants, aged 18 to 60 (mean 25.24 ± 8.8), completed the Adolescent/Adult Sensory Profile, mindful attention and awareness scale, and cognitive and affective mindfulness scale.FindingsAspects of mindfulness associated with attention and awareness were significantly negatively related to sensory processing patterns associated with passive behavioral strategies (low registration and sensory sensitivity).ConclusionIndividuals whose sensory processing patterns are characterized by poor awareness experience more mind wandering and distraction in daily life. Occupational therapists should consider mindfulness techniques when treating individuals with sensory processing disorders. In addition, information about sensory processing styles should be incorporated into relaxation and mindfulness-based interventions.

Features of Conditioned Reflex Fear in Active and Passive Rabbits

The individual typological features of conditioned reflex fear were studied in groups of active and passive rabbits selected on the basis of analysis of their behavior in the open field and dark-light boxes by developing a classical conditioned reflex using a combination of a light (4 sec) and electrocutaneous stimulation of the hindpaws (10 Hz, 0.5 sec). Changes in respiratory and heart rates in the animals in response to stimulus combinations during training were analyzed. Conditioned defensive responses to light (freezing) were associated with reductions in respiratory and heart rates occurring in response to the light, i.e., before electrocutaneous stimulation. Active rabbits contrasted with passive rabbits in showing greater motor reactions, higher heart rates, delayed onset of conditioned reflex respiratory slowing to a later stage of training, and the absence of persistent bradycardia. Thus, judging from the these few autonomic measures, active animals experienced lower levels of fear than passive animals. The active and passive behavioral strategies persisted after training.

Effects of Administration of an Agonist and an Antagonist of GABAA Receptors into the Amygdala in Rabbits on the Respiratory and Cardiac Components of Conditioned Reflex Fear

The role of the GABAergic system of the amygdala in the autonomic and behavioral manifestations of conditioned reflex fear was studied in groups of “active” and “passive” rabbits selected on the basis of testing in an open field and a dark-light chamber. The animals were trained to a conditioned reflex by combining light (4 sec) and electrocutaneous stimulation of the hindlimbs (1 sec, 10 Hz). The extent of conditioned reflex fear was assessed in terms of changes in heart rate and respiratory movements in response to the conditioned and unconditioned stimuli as compared with rates prior to training. After training, a GABA receptor agonist (muscimol, 0.1 μg/1 μl) or antagonist bicuculline metabromide, 0.5 μg/1 μl) was applied locally into the right or left basal nucleus of the amygdala via a cannula. Administration of muscimol into the amygdala induced more extensive autonomic changes in passive rabbits than in active, eliminating the reduction in the rate of respiratory movements in response to the conditioned stimulus typical of freezing, as well as weakening or altering responses to electrocutaneous stimulation, as judged by heart and respiratory rates. Activation of the left amygdala with bicuculline increased the probability of active motor reactions in active rabbits, while activation of the right amygdala, conversely, increased the probability of freezing. These results provide evidence of the nonequivalence of the GABAergic system of the amygdala in animals with active and passive behavioral strategies.

Effects of Intra-Amygdalar Administration of GABAA Receptor Agonists and Antagonists on the Behavior of Active and Passive Rabbits in Emotionally Negative Situations

The effects of local administration of an agonist (muscimol hydrobromide, 0.1 μg in 1 μl) and antagonist (bicuculline methiodide, 0.05, 0.1, 0.5 μg in 1 μl) of GABAA receptors on the behavior of active and passive rabbits were studied in an open field test, dark–light box, and on exposure to emotionally significant stimuli. Treatment effects differed in animals with active and passive behavioral strategies: active rabbits were more sensitive to bicuculline, while passive animals were more sensitive to muscimol. In active animals, bicuculline had anxiolytic actions in the open field and dark–light box and motor-activating influences in response to emotionally significant stimuli. Muscimol had anxiolytic effects in passive rabbits and sedative actions in animals of both groups. Differences in the efficacies of right- and left-sided dosage sites were seen: more effective changes in behavior were produced when bicuculline was given into the left amygdala, while muscimol was more effective when given in the right amygdala. The anxiolytic effect appeared when bicuculline was given into the left amygdala in active rabbits and when muscimol was given into the right amygdala in passive animals. These results provide evidence of the existence of individual-typological and interhemisphere differences in the functioning of the GABAergic system of the amygdala.

Network Activity of “Interneurons” and Large Cells in the Amygdala in Active and Passive Rabbits

Cross-correlation histogram studies demonstrated differences in the interactions of presumptive small “interneurons” and large principal cells in the central and basal nuclei of the amygdala in rabbits in emotionally negative situations. “Interneurons” displayed greater network activity than principal cells. “Interneurons” more frequently had input and output excitatory and inhibitory connections with neighboring neurons, and the latencies of their connections with other cells were shorter, than in the case of principal cells. Interactions between “interneurons” and principal cells in emotionally negative situations differed in animals with active and passive behavioral strategies. In passive rabbits, there were more inhibitory connections with “interneurons” from any other cells than in active animals, while passive animals showed fewer excitatory and inhibitory connections from “interneurons” to principal cells.

Interaction of Neurons in the Basal and Central Nuclei of the Amygdala in Rabbits with Active and Passive Behavioral Strategies in Emotionally Negative Situations

Cross-correlation histograms were used to study the interaction between neurons in the central and basal nuclei of the amygdala in groups of passive and active rabbits in emotionally negative situations. The animals’ behavior was tested in an open field, a dark-light box, and on exposure to emotionally significant stimuli. Rabbits of the different groups retained a particular behavioral strategy in different tests. Intergroup differences were seen in the interaction of close-lying amygdalar neurons. Passive animals showed more excitatory and fewer inhibitory interneuronal connections with latent periods from 50 to 150 msec than active animals; interactions between neurons were rarer at the delta1 and theta2 frequencies. Asymmetry in interhemisphere interactions of neurons with right-sided dominance was seen in passive animals but was absent in active animals. These data provide evidence that the amygdala is involved in selecting the passive or active behavioral strategy, passive animals showing higher levels of activation of the amygdala than active rabbits.

Interhemisphere Asymmetry of the Hippocampus and Neocortex as a Correlate of the Active and Passive Behavioral Strategies in Emotionally Negative Situations

Cross-correlation histograms were used to study the interhemisphere interactions of cells in bilateral leads from the parietal and sensorimotor areas of the neocortex and hippocampal field CA1 in groups of rabbits with active and passive behavioral strategies in an open field test. Passive rabbits showed asymmetry in the bilateral interaction: with right-sided dominance in the neocortex and left-sided dominance in the hippocampus. Active animals, conversely, showed left-hemisphere dominance in the neocortex, with no asymmetry in the hippocampus. Brain lateralization was apparent as motor asymmetry in relation to preference for right or left turns in the open field: passive rabbits showed a relative preference for left turns and active animals for right turns. In all animals, systemic administration of the GABAB receptor agonist phenibut, which decreases behavioral reactivity to emotionally significant stimuli, eliminated the interhemisphere asymmetry seen in normal conditions in emotionally negative situations. These results provide evidence that interhemisphere asymmetry at the levels of the neocortex and hippocampus is linked with the individual-typological characteristics of the animals and reflects readiness for the most typical types of behavioral responding in active and passive animals.

Effects of Corticoliberin on Synaptic Transmission in Rat Olfactory Cortex Slices in a Water Immersion Model of Depression

Corticoliberin (corticotrophin-releasing factor, CRF, CRH) is an active regulator of endocrine, autonomic, and immune functions in stress, as well as a mediator of anxiety, determining the behavioral stress response. The present report describes studies of its action on neuron activity evoked by microstimulation of olfactory cortex slices. Behavioral testing in a T maze was used to select individuals with a passive behavioral strategy from a population of Wistar rats, and the animals were subjected to water immersion. Olfactory cortex slices were prepared 10 days later and evoked focal potentials were recorded on perfusion with medium containing corticoliberin (0.1 microM). Among active rats, 60% of slices retained high excitability after stress, and corticoliberin produced only insignificant reductions in the amplitudes of excitatory potentials in these slices, simultaneously increasing the amplitudes of inhibitory potentials. Low excitability was found in 40% of slices from active stressed rats, and corticoliberin had a significant inhibitory effect in these slices. Addition of corticoliberin to the incubation medium used for slices from passive rats with initially low excitability led to complete blockade of synaptic transmission. These data support the involvement of corticoliberin in the development of depression.

Increased CRF2 expression in the dorsal raphe is associated with passive behavioral responses to stress

The dorsal raphe (DR)‐serotonin (5‐HT) system is implicated in stress‐related psychiatric disorders, like depression. Corticotropin‐releasing factor (CRF) modulates activity of this system during stress via activation of two receptors: CRF1 and CRF2. CRF1 mediated inhibition of the DR‐5‐HT system facilitates active behavioral responses to stress. In contrast, CRF2 can excite the DR‐5‐HT system, an effect that may mediate passive responses to stress. Here we used genetic, behavioral, and pharmacological models to determine whether changes in CRF2 expression in the DR are associated with passive behavior. Western Blots were first used to demonstrate that rats of the behaviorally passive Wistar Kyoto strain express more CRF2 protein in the DR than Sprague‐Dawley (SD) rats. In the second experiment, SD rats exposed to chronic social defeat, which results in passive behavior on the forced swim test (FST), expressed more CRF2 in the DR than their unstressed counterparts. Finally, chronic antidepressant treatment that decreases passive responses on the FST resulted in fewer CRF2 in the DR. None of these models altered DR expression of CRF1. These studies suggest that greater CRF2 expression in the DR correlates with a passive behavioral strategy. Because passive responses to stress are associated with increased vulnerability to depression in humans, CRF2 may be a novel target for treating stress‐related disorders.

Electrophysiological characteristics of depressive states in rats with passive strategies of adaptive behavior

The behavior of rats in a T-maze was used to select individuals with a passive strategy of adaptive behavior from a population of Wistar rats. These animals were subjected to water immersion and olfactory cortex slices were prepared from the brain 10 days later and used for recording of evoked focal potentials and the effects of tetanic stimulation. Postsynaptic potentials, of both the AMPA and NMDA types, were initially of decreased amplitude in passive rats. After unavoidable stress, the suppression of excitatory potentials increased and there was a simultaneous increase in the amplitude of inhibitory GABAB-ergic mechanisms. Addition of corticoliberin (10(-10) M) to the incubation medium led to reversible blockade of synaptic transmission. Tetanic stimulation of slices from stressed rats led to the development of posttetanic depression in 84% of cases and to post-tetanic potentiation in 12%; this is evidence for profound changes in synaptic transmission. Thus, activation of corticoliberinergic mechanisms in cortical structures does not promote recovery from depressive states in rats with the passive behavioral strategy induced by unavoidable stress.