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Communications Biology May 2024Avoidance, a hallmark of anxiety-related psychopathology, often comes at a cost; avoiding threat may forgo the possibility of a reward. Theories predict that optimal...
Avoidance, a hallmark of anxiety-related psychopathology, often comes at a cost; avoiding threat may forgo the possibility of a reward. Theories predict that optimal approach-avoidance arbitration depends on threat-induced psychophysiological states, like freezing-related bradycardia. Here we used model-based fMRI analyses to investigate whether and how bradycardia states are linked to the neurocomputational underpinnings of approach-avoidance arbitration under varying reward and threat magnitudes. We show that bradycardia states are associated with increased threat-induced avoidance and more pronounced reward-threat value comparison (i.e., a stronger tendency to approach vs. avoid when expected reward outweighs threat). An amygdala-striatal-prefrontal circuit supports approach-avoidance arbitration under threat, with specific involvement of the amygdala and dorsal anterior cingulate (dACC) in integrating reward-threat value and bradycardia states. These findings highlight the role of human freezing states in value-based decision making, relevant for optimal threat coping. They point to a specific role for amygdala/dACC in state-value integration under threat.
Topics: Humans; Male; Magnetic Resonance Imaging; Adult; Female; Young Adult; Bradycardia; Avoidance Learning; Amygdala; Reward; Gyrus Cinguli; Fear; Anxiety; Heart Rate; Decision Making
PubMed: 38755409
DOI: 10.1038/s42003-024-06267-6 -
Chemosphere Jul 2024Bioplastics are considered sustainable alternatives to conventional microplastics which are recognized as a threat to terrestrial ecosystems. However, little is known...
Ecotoxicity evaluation using the avoidance response of the oribatid mite Oppia nitens (Acari: Oribatida) in bioplastics, microplastics, and contaminated Superfund field sites.
Bioplastics are considered sustainable alternatives to conventional microplastics which are recognized as a threat to terrestrial ecosystems. However, little is known about the potential ecotoxicological effects of bioplastics on soil fauna and ecosystems. The present study assessed the toxicity of microplastics [Polystyrene (PS), Polyethylene (PE)] and bioplastics [Polyvinyl alcohol (PVA), Sodium polyacrylate (NaPa) on a key soil fauna Oppia nitens, a soil oribatid mite, and investigated the ecological relevance of O. nitens avoidance response as a valuable tool for the risk assessment of contaminated soils such as the Superfund sites. Findings showed that the mites' net response indicated avoidance behavior such that in most cases as concentrations of micro- and bioplastics increased, so did the avoidance responses. The avoidance EC endpoints showed PS < PE < PVA < NaPa, indicating higher deleterious effects of microplastics. High toxicity of PS in soils to O. nitens at EC of 165 (±25) mg/kg compared to bioplastics and other known contaminants poses an enormous threat to soil. For bioplastics in this study, there were no significant avoidances at concentrations up to 16,200 mg/kg compared to PS and PE which showed avoidance responses at 300 and 9000 mg/kg respectively, implying that bioplastics might be relatively safer to soil mites compared to conventional microplastics. Also, results indicated that long-term heavy metal pollution such as in contaminated Superfund sites decreased microbial biomass; a useful bioindicator of soil pollution. Furthermore, O. nitens avoidance of heavy metals contaminated sites demonstrated the ecological relevance of avoidance response test when assessing the habitat integrity of contaminated soil. The present study further supports the inclusion of the oribatid mite, O. nitens in the ecological risk assessment of contaminants in soil.
Topics: Animals; Microplastics; Soil Pollutants; Mites; Ecotoxicology; Soil; Environmental Monitoring; Polyethylene; Ecosystem; Risk Assessment; Plastics; Avoidance Learning
PubMed: 38740337
DOI: 10.1016/j.chemosphere.2024.142301 -
Journal of Neuroimmune Pharmacology :... May 2024Suppression of immune functions can be elicited by behavioural conditioning using drugs such as cyclosporin A or rapamycin. Nevertheless, little is known about the...
Suppression of immune functions can be elicited by behavioural conditioning using drugs such as cyclosporin A or rapamycin. Nevertheless, little is known about the underlying mechanisms and generalisability of this phenomenon. Against this background, the present study investigated whether the pharmacological properties of fingolimod (FTY720), an immunosuppressive drug widely applied to treat multiple sclerosis, can be conditioned in rats by means of taste-immune associative learning. For this purpose, a conditioned taste avoidance paradigm was used, pairing the presentation of a novel sweet drinking solution (saccharin or sucrose) as conditioned stimulus (CS) with therapeutically effective doses of FTY720 as unconditioned stimulus (US). Subsequent re-exposure to the CS at a later time point revealed that conditioning with FTY720 induced a mild conditioned taste avoidance only when saccharin was employed as CS. However, on an immunological level, neither re-exposure with saccharin nor sucrose altered blood immune cell subsets or splenic cytokine production. Despite the fact that intraperitonally administered FTY720 could be detected in brain regions known to mediate neuro-immune interactions, the present findings show that the physiological action of FTY720 is not inducible by mere taste-immune associative learning. Whether conditioning generalises across all small-molecule drugs with immunosuppressive properties still needs to be investigated with modified paradigms probably using distinct sensory CS. Moreover, these findings emphasize the need to further investigate the underlying mechanisms of conditioned immunomodulation to assess the generalisability and usability of associative learning protocols as supportive therapies in clinical contexts.
Topics: Animals; Fingolimod Hydrochloride; Rats; Immunosuppressive Agents; Male; Rats, Wistar; Leukocytes; Avoidance Learning; Conditioning, Classical; Propylene Glycols; Taste; Saccharin
PubMed: 38733535
DOI: 10.1007/s11481-024-10122-0 -
Human Movement Science Jun 2024Individuals rely on visual information to determine when to adapt their behaviours (i.e., by changing path and/or speed) to avoid an approaching object or person. After...
Individuals rely on visual information to determine when to adapt their behaviours (i.e., by changing path and/or speed) to avoid an approaching object or person. After initiating an avoidance behaviour, individuals may control the space (i.e., minimum clearance distance) between themselves and another person or object. The current study aimed to determine the action strategies of young adults while avoiding a virtual pedestrian approaching along a 45° angle in an attentionally demanding task. Twenty-one young adults (22.9 ± 1.9 yrs., 11 males) were immersed in a virtual environment and were instructed to walk along a 7.5 m path towards a goal located along the midline. Two virtual pedestrians (VP) positioned 2.83 m to the left and right of the midline approached participants on a 45° angle. To manipulate the point at which the participants and the VP would intersect during different trials, the VP approached at one of three speeds: 0.8×, 1.0×, or 1.2× each participants' average walking speed. Participants were instructed to walk to a goal without colliding with the VP while performing the attention task; reporting whether a shape changed above the VPs' heads. Results revealed that young adults did not modulate their timing of avoidance to the approach characteristics of the VP, as they consistently avoided the collision 1.67 s after the VP began moving. However, young adults seem to control how they avoid an oncoming collision by maintaining a consistent safety margin after an avoidance behaviour was initiated.
Topics: Humans; Male; Young Adult; Attention; Female; Pedestrians; Virtual Reality; Walking; Adult; Avoidance Learning; Accidents, Traffic; Psychomotor Performance; Walking Speed; Orientation; User-Computer Interface
PubMed: 38728852
DOI: 10.1016/j.humov.2024.103226 -
Science Advances May 2024Corticotropin releasing factor (CRF) network in the oval nucleus of bed nuclei of the stria terminalis (ovBNST) is generally indicated in stress, but its role in...
Corticotropin releasing factor (CRF) network in the oval nucleus of bed nuclei of the stria terminalis (ovBNST) is generally indicated in stress, but its role in female-biased susceptibility to anxiety is unknown. Here, we established a female-biased stress paradigm. We found that the CRF release in ovBNST during stress showed female-biased pattern, and ovBNST CRF neurons were more prone to be hyperexcited in female mice during stress in both in vitro and in vivo studies. Moreover, optogenetic modulation to exchange the activation pattern of ovBNST CRF neurons during stress between female and male mice could reverse their susceptibility to anxiety. Last, CRF receptor type 1 (CRFR1) mediated the CRF-induced excitation of ovBNST CRF neurons and showed female-biased expression. Specific knockdown of the CRFR1 level in ovBNST CRF neurons in female or overexpression that in male could reverse their susceptibility to anxiety. Therefore, we identify that CRFR1-mediated hyperexcitation of ovBNST CRF neurons in female mice encode the female-biased susceptibility to anxiety.
Topics: Animals; Female; Male; Mice; Anxiety; Avoidance Learning; Behavior, Animal; Corticotropin-Releasing Hormone; Neurons; Receptors, Corticotropin-Releasing Hormone; Septal Nuclei; Stress, Psychological
PubMed: 38728397
DOI: 10.1126/sciadv.adk7636 -
Neuroscience Jun 2024The brown rat (Rattus norvegicus) is known to show three types of behavioral responses to novel objects. Whereas some rats are indifferent to novel objects, neophobic...
The brown rat (Rattus norvegicus) is known to show three types of behavioral responses to novel objects. Whereas some rats are indifferent to novel objects, neophobic and neophilic rats show avoidance and approach behavior, respectively. Here, we compared the dopaminergic, serotonergic, and noradrenergic systems immunohistochemically among these rats. Trapped wild rats and laboratory rats were first individually exposed to the novel objects in their home cage. Wild rats were divided into neophobic and indifferent rats depending on their behavioral responses. Similarly, laboratory rats were divided into neophilic and indifferent rats. Consistent with the behavioral differences, in the paraventricular nucleus of the hypothalamus, Fos expression in corticotropin-releasing hormone-containing neurons was higher in the neophobic rats than in the indifferent rats. In the anterior basal amygdala, the neophobic rats showed higher Fos expression than the indifferent rats. In the posterior basal amygdala, the neophobic and neophilic rats showed lower and higher Fos expressions than the indifferent rats, respectively. When we compared the neuromodulatory systems, in the dorsal raphe, the number of serotonergic neurons and Fos expression in serotonergic neurons increased linearly from neophobic to indifferent to neophilic rats. In the ventral tegmental area, Fos expression in dopaminergic neurons was higher in the neophilic rats than in the indifferent rats. These results demonstrate that approach/avoidance behavior to novel objects is correlated with the serotonergic and dopaminergic systems in the brown rat. We propose that the serotonergic system suppresses avoidance behavior while the dopaminergic system enhances approach behavior to novel objects.
Topics: Animals; Male; Rats; Avoidance Learning; Serotonergic Neurons; Dopaminergic Neurons; Dopamine; Serotonin; Proto-Oncogene Proteins c-fos; Brain; Exploratory Behavior; Behavior, Animal; Corticotropin-Releasing Hormone
PubMed: 38723837
DOI: 10.1016/j.neuroscience.2024.05.003 -
Neuroscience and Biobehavioral Reviews Jul 2024The mesopontine tegmentum, comprising the pedunculopontine tegmentum (PPN) and the laterodorsal tegmentum (LDT), is intricately connected to various regions of the basal... (Review)
Review
The mesopontine tegmentum, comprising the pedunculopontine tegmentum (PPN) and the laterodorsal tegmentum (LDT), is intricately connected to various regions of the basal ganglia, motor systems, and limbic systems. The PPN and LDT can regulate the activity of different brain regions of these target systems, and in this way are in a privileged position to modulate motivated behaviours. Despite recent findings, the PPN and LDT have been largely overlooked in discussions about the neural circuits associated with reward and aversion. This review aims to provide a timely and comprehensive resource on past and current research, highlighting the PPN and LDT's connectivity and influence on basal ganglia and limbic, and motor systems. Seminal studies, including lesion, pharmacological, and optogenetic/chemogenetic approaches, demonstrate their critical roles in modulating reward/aversive behaviours. The review emphasizes the need for further investigation into the associated cellular mechanisms, in order to clarify their role in behaviour and contribution for different neuropsychiatric disorders.
Topics: Reward; Humans; Animals; Tegmentum Mesencephali; Basal Ganglia; Avoidance Learning; Neural Pathways
PubMed: 38718986
DOI: 10.1016/j.neubiorev.2024.105702 -
Neuroscience Jun 2024The present research study aimed to investigate the role of Ascorbic acid (AA) on synaptic plasticity, learning, and memory impairment induced by unpredicted chronic...
Ascorbic Acid Supplementation Improves Adolescent Stress-induced Cognitive Impairment Through Restoration of Behavioral, Biochemical and Electrophysiological Alterations in Male Rats.
The present research study aimed to investigate the role of Ascorbic acid (AA) on synaptic plasticity, learning, and memory impairment induced by unpredicted chronic mild stress (CUMS) in adolescent male rats. Adolescent male rats were divided into: 1) vehicle, 2) CUMS, 3-5) CUMS plus various doses of AA by oral gavage (CUMS-10/100/400 mg/kg), and 6) AA400 mg/kg by oral gavage. In Morris Water Maze, the time latency decreased, while the time spent in the target quadrant increased in CUMS group treated with AA at the dose of 400 mg/kg. In passive avoidance, the latency of entering into the dark chamber decreased in CUMS group treated with AA (400 mg/kg). In biochemical test results, nitrite and MDA significantly decreased, while thiol content, SOD, and catalase activity in CUMS group that received AA400mg/kg was increased. IL-10, BDNF and Ki67 increased, while TNF-a and AChE activity were decreased in CUMS group treated with AA simultaneously. The results of our study showed that chronic stress during adolescence could cause learning and memory disorders as well as synaptic plasticity. In addition, we showed that AA can prevent this problem by reducing oxidative stress, inflammation, increasing the amount of BDNF, and neurogenesis.
Topics: Animals; Male; Ascorbic Acid; Stress, Psychological; Rats; Cognitive Dysfunction; Oxidative Stress; Neuronal Plasticity; Antioxidants; Hippocampus; Rats, Wistar; Dietary Supplements; Brain-Derived Neurotrophic Factor; Maze Learning; Avoidance Learning
PubMed: 38718917
DOI: 10.1016/j.neuroscience.2024.04.012 -
Behavioural Brain Research Jun 2024Prenatal stress (PS), in both humans and animals, presents a potential risk to the mother and her fetus throughout gestation. PS is always associated with physiological...
Prenatal stress (PS), in both humans and animals, presents a potential risk to the mother and her fetus throughout gestation. PS is always associated with physiological changes that alter embryonic development and predispose the individual to lifelong health problems, including susceptibility to mental illness. This study aims to identify the harmful effects of prenatal restraint stress (PRS), commonly employed to induce stress painlessly and without any lasting debilitation during gestation. This stress is applied to pregnant Swiss albino mice from E7.5 to delivery for three hours daily. Our results show that PS affects dams' weight gain during the gestational period; moreover, the PS dams prefer passive nursing, exhibit a lower percentage of licking and grooming, and impair other maternal behaviors, including nesting and pup retrieval. Concerning the offspring, this stress induces neurobehavioral impairments, including a significant increase in the time of recovery of the young stressed pups in the surface righting reflex, the latency to avoid the cliff in the cliff avoidance test, longer latencies to accomplish the task in negative geotaxis, and a lower score in swimming development. These alterations were accompanied by increased Malondialdehyde activity (MDA) at PND17 and 21 and downregulation of AchE activity in the whole brain of pups on postnatal days 7 and 9. These findings demonstrated that PS causes deleterious neurodevelopmental impairments that can alter various behaviors later in life.
Topics: Animals; Pregnancy; Female; Prenatal Exposure Delayed Effects; Mice; Restraint, Physical; Stress, Psychological; Oxidative Stress; Maternal Behavior; Malondialdehyde; Animals, Newborn; Brain; Male; Acetylcholinesterase; Behavior, Animal; Reflex, Righting; Avoidance Learning
PubMed: 38710451
DOI: 10.1016/j.bbr.2024.115025 -
Addiction Biology May 2024Opioid addiction is a relapsing disorder marked by uncontrolled drug use and reduced interest in normally rewarding activities. The current study investigated the impact...
Opioid addiction is a relapsing disorder marked by uncontrolled drug use and reduced interest in normally rewarding activities. The current study investigated the impact of spontaneous withdrawal from chronic morphine exposure on emotional, motivational and cognitive processes involved in regulating the pursuit and consumption of food rewards in male rats. In Experiment 1, rats experiencing acute morphine withdrawal lost weight and displayed somatic signs of drug dependence. However, hedonically driven sucrose consumption was significantly elevated, suggesting intact and potentially heightened reward processing. In Experiment 2, rats undergoing acute morphine withdrawal displayed reduced motivation when performing an effortful response for palatable food reward. Subsequent reward devaluation testing revealed that acute withdrawal disrupted their ability to exert flexible goal-directed control over reward seeking. Specifically, morphine-withdrawn rats were impaired in using current reward value to select actions both when relying on prior action-outcome learning and when given direct feedback about the consequences of their actions. In Experiment 3, rats tested after prolonged morphine withdrawal displayed heightened rather than diminished motivation for food rewards and retained their ability to engage in flexible goal-directed action selection. However, brief re-exposure to morphine was sufficient to impair motivation and disrupt goal-directed action selection, though in this case, rats were only impaired in using reward value to select actions in the presence of morphine-paired context cues and in the absence of response-contingent feedback. We suggest that these opioid-withdrawal induced deficits in motivation and goal-directed control may contribute to addiction by interfering with the pursuit of adaptive alternatives to drug use.
Topics: Animals; Substance Withdrawal Syndrome; Reward; Motivation; Male; Goals; Morphine; Rats; Morphine Dependence; Narcotics; Conditioning, Operant
PubMed: 38706098
DOI: 10.1111/adb.13393