Search results for "void"

Dopamine neurons drive fear extinction learning by signaling the omission of expected aversive outcomes

2018

Extinction of fear responses is critical for adaptive behavior and deficits in this form of safety learning are hallmark of anxiety disorders. However, the neuronal mechanisms that initiate extinction learning are largely unknown. Here we show, using single-unit electrophysiology and cell-type specific fiber photometry, that dopamine neurons in the ventral tegmental area (VTA) are activated by the omission of the aversive unconditioned stimulus (US) during fear extinction. This dopamine signal occurred specifically during the beginning of extinction when the US omission is unexpected, and correlated strongly with extinction learning. Furthermore, temporally-specific optogenetic inhibition o…

Effects of social stress and clomipramine on emotional memory in mice.

2017

We have previously observed impairing effects of social defeat stress (CSDS) on inhibitory avoidance (IA) in mice. Given the similarity between changes produced by social stress in animals and symptoms of certain human psychopathologies such as depression and anxiety, the effects of the antidepressant clomipramine on IA impairment produced by CSDS were evaluated in the present study. Male CD1 mice were randomly assigned to the groups: non-stressed+saline, non-stressed+clomipramine, stressed+saline and stressed+clomipramine. Stressed animals were subjected to daily agonistic encounters (10 min) in the home cage of the aggressor over a 20-day period. Just before each encounter, non-stressed a…

Indomethacin counteracts the effects of chronic social defeat stress on emotional but not recognition memory in mice

2017

We have previously observed the impairing effects of chronic social defeat stress (CSDS) on emotional memory in mice. Given the relation between stress and inflammatory processes, we sought to study the effectiveness of the anti-inflammatory indomethacin in reversing the detrimental effects of CSDS on emotional memory in mice. The effects of CSDS and indomethacin on recognition memory were also evaluated. Male CD1 mice were randomly divided into four groups: non-stressed + saline (NS+SAL); non-stressed + indomethacin (NS+IND); stressed + saline (S+SAL); and stressed + indomethacin (S+IND). Stressed animals were exposed to a daily 10 min agonistic confrontation (CSDS) for 20 days. All subjec…

A new “sudden fright paradigm” to explore the role of (epi)genetic modulations of the DAT gene in fear-induced avoidance behavior

2020

Alterations in dopamine (DA) reuptake are involved in several psychiatric disorders whose symptoms can be investigated in knock out rats for the DA transporter (DAT-KO). Recent studies evidenced the role of epigenetic DAT modulation in depressive-like behavior. Accordingly, we used heterozygous (HET) rats born from both HET parents (termed MIX-HET), compared to HET rats born from WT-mother and KO-father (MAT-HET), implementing the role of maternal care on DAT modulation. We developed a "sudden fright" paradigm (based on dark-light test) to study reaction to fearful inputs in the DAT-KO, MAT-HET, MIX-HET, and WT groups. Rats could freely explore the whole 3-chambers apparatus; then, they wer…

The Severity of Acute Stress Is Represented by Increased Synchronous Activity and Recruitment of Hypothalamic CRH Neurons

2016

The hypothalamo-pituitary-adrenocortical (HPA) axis regulates stress physiology and behavior. To achieve an optimally tuned adaptive response, it is critical that the magnitude of the stress response matches the severity of the threat. Corticotropin-releasing hormone (CRH) released from the paraventricular nucleus of the hypothalamus is a major regulator of the HPA axis. However, how CRH-producing neurons in an intact animal respond to different stressor intensities is currently not known. Using two-photon calcium imaging on intact larval zebrafish, we recorded the activity of CRH cells, while the larvae were exposed to stressors of varying intensity. By combining behavioral and physiologic…

Optogenetically enhanced pituitary corticotroph cell activity post-stress onset causes rapid organizing effects on behaviour

2016

The anterior pituitary is the major link between nervous and hormonal systems, which allow the brain to generate adequate and flexible behaviour. Here, we address its role in mediating behavioural adjustments that aid in coping with acutely threatening environments. For this we combine optogenetic manipulation of pituitary corticotroph cells in larval zebrafish with newly developed assays for measuring goal-directed actions in very short timescales. Our results reveal modulatory actions of corticotroph cell activity on locomotion, avoidance behaviours and stimulus responsiveness directly after the onset of stress. Altogether, the findings uncover the significance of endocrine pituitary cell…

2018

Experiential avoidance, cognitive defusion, and mindfulness have all been associated with psychological disorders and well-being. This study investigates whether they predict psychological distress, i.e., symptoms of burnout, depression, stress and anxiety, in parents of children with chronic conditions. We hypothesized that these factors would exhibit a large degree of common variance, and that when compared to mindfulness and defusion, experiential avoidance on its own would predict a larger proportion of unique variance. 75 parents of children with chronic conditions having burnout symptoms who participated in an intervention study completed measures of burnout, stress, anxiety, depressi…

Developmental trajectories of experiential avoidance and depressive symptoms and association to health behaviors among adolescents during brief guide…

2021

Abstract While many children and adolescents experience psychological problems with up to 20 percent estimated to develop a mental health problem, only few receive treatment. Online interventions can help respond to the need of support among young people without requiring considerable resources. However, relatively few studies have examined the efficacy of online interventions for youth and more research is needed to understand individual differences in benefiting from these interventions. The current study sought to examine different developmental trajectories of experiential avoidance and depressive symptoms and their association to health behaviors measured at baseline during a brief gui…

Autonomous vehicle with communicative driving for pedestrian crossing: Trajectory optimization

2020

Connected and autonomous vehicles (CAV) is a key technology for this century. One of the main challenges is to define a smart interaction behavior of CAV with the other road users. The challenge is mainly raised at conflicting points where path of CAV intersects with the other users. Recent studies show interaction with humans is a big challenge. It not only requires a collision avoidance system but also more communicative behaviors of the CAV. More precisely, pedestrian needs to understand the intention of the incoming CAV whether it will cross first or not according to its speed profile. One way to overcome this issue is to design optimal trajectory control of the CAV that matches with th…

Personal variables, motivation and avoidance learning strategies in undergraduate students

2014

Abstract This study examines the relationships among students' personal variables, their initial motivation and the avoidance learning strategies they used during the teaching/learning process followed in the Educational Psychology subject matter. The sample comprised 195 Spanish undergraduate students who studied Educational Psychology. A questionnaire was administered at the beginning of the academic year to measure students' personal variables and their initial motivation, while another was administered at the end of the academic year to measure students' involvement in their learning process through the avoidance strategies they used. The data analysis was done by using structural equat…