Farmed Salmon Show No Pathological Alterations When Exposed to Acoustic Treatment for Sea Lice Infestation

The use of bioacoustic methods to address sea lice infestation in salmonid farming is a promising innovative method but implies an exposure to sound that could affect the fish. An assessment of the effects of these techniques related to the salmon’s welfare is presented here. The fish were repeatedly exposed to 350 Hz and 500 Hz tones in three- to four-hour exposure sessions, reaching received sound pressure levels of 140 to 150 dB re 1 µPa2, with the goal of reaching total sound exposure levels above 190 dB re 1 µPa2 s. Gross pathology and histopathological analysis performed on exposed salmons’ organs did not reveal any lesions that could be associated to sound exposure. The analysis of their otoliths through electron microscopy imaging confirmed that the sound dose that was used to impair the lice had no effects on the fish auditory organs.

Efficacy of exposure in group settings for youth with posttraumatic stress symptoms

Background Exposure to traumatic experiences is a fundamental part of evidence-based trauma-focused cognitive behavioral treatment (CBT) but in group settings it is discussed controversially among researchers and practitioners. This study aims to examine the individual participants’ stress level during group sessions with exposure and disclosure of traumatic events. Method N = 47 traumatized youth (Mage = 17.00, 94% male) participated in a group intervention comprising six 90-min group sessions (exposure in sessions 2–5). It is based on trauma-focused CBT principles. The individual stress level was assessed by the participants and group facilitators at the beginning, during, and at the end of every session. Results During the sessions including exposure, the stress level of the participants was higher than during sessions without exposure (Z = − 3.79; p ≤ .001). During the exposure sessions, the participants showed significant changes in stress level (d = 0.34–0.87) following an inverse U-shaped trend. Conclusion The results show that exposure is feasible within the scope of a trauma-focused group intervention for youth. The further dissemination of trauma-focused group treatments is an important component in the mental health care of children and youth who are traumatized.

Assessing the performance of Sub-Saharan African (SSA) railways based on an integrated Entropy-MARCOS approach

In this study, the performance of Sub-Saharan African railways systems (SSA) is assessed by using an integrated Entropy-MARCOS (Measurement Alternatives and Ranking according to COmpromise Solution) - based methodology. In the first phase, the Entropy method is employed to determine the weights of each sub-criterion of the decision model. This process identifies six main criteria, i.e., safety, security, internal business aspect, intermodal aspect, innovation, and learning aspect, and customer satisfaction which are further supplemented by 13 sub-criteria. In the second phase, the MARCOS method is used to rank the countries based on their railway performance assessment. Based on the results from the proposed method, a sensitivity analysis was carried out through a comparative analysis with seven other multi-criteria decision-making (MCDM) methods. The results of the study indicate that the most weighted sub-criterion is the labor productivity (internal business perspective criteria) followed by the terrorist incidence (security criteria) and the number of employees going through training/exposure sessions (innovation and learning perspective criteria). Moreover, it was revealed that Kenya is the best alternative in terms of its railway performance followed by Ethiopia, Cameroon, Nigeria, and Ghana. Based on the findings from this study, decision-makers can be assisted during the operative, designing, and planning investigations of the railway system through the consideration of these parameters as insert indicators. Also, the findings can help as a benchmark for the performance analysis of other railway systems in other African countries.

The Role of Context Conditioning in the Reinstatement of Responding to an Alcohol-Predictive Conditioned Stimulus

Re-exposure to an unconditioned stimulus (US) can reinstate extinguished conditioned responding elicited by a conditioned stimulus (CS). We tested the hypothesis that the reinstatement of responding to an appetitive CS is driven by an excitatory association formed between the US and the context that the US was ingested in during US re-exposure. Male, Long-Evans rats were acclimated to drinking alcohol (15%, v/v) in the home-cage, then trained to associate an auditory CS with an alcohol-US that was delivered into a fluid port for oral intake. During subsequent extinction sessions, the CS was presented as before, but without alcohol. After extinction, rats were re-exposed to alcohol as in training, but without the CS (US re-exposure). 24 h later at test, the CS was presented as in training, but without alcohol. First, we tested the effect of extinguishing the context-alcohol association, formed during alcohol re-exposure, on reinstatement. Conducting four context extinction sessions across four days (spaced extinction) after the US re-exposure session did not impact reinstatement. However, four context extinction sessions conducted across two days (massed extinction) prevented reinstatement. Next, we conducted alcohol re-exposure in a context that either differed from, or was the same as, the test context. One alcohol re-exposure session in a different context did not affect reinstatement, however, three alcohol re-exposure sessions in a different context significantly reduced reinstatement during the first CS trial. These results partially support the view that a context-US association formed during US re-exposure drives the reinstatement of responding to an appetitive, alcohol-predictive CS.

Efficacy of Exposure in Group Settings for Youth With Posttraumatic Stress Symptoms

Background: Exposure to traumatic experiences is a fundamental part of evidence-based trauma-focused cognitive behavioral treatment (CBT) but in group settings it is discussed controversially among researchers and practitioners. This study aims to examine the individual participants’ stress level during group sessions with exposure and disclosure of traumatic events.Method: N = 47 traumatized youth (Mage = 17.00, 94% male) participated in a group intervention comprising six 90-minute group sessions (exposure in sessions 2-5). It is based on trauma-focused CBT principles. The individual stress level was assessed by the participants and group facilitators at the beginning, during, and at the end of every session. Results: During the sessions including exposure, the stress level of the participants was higher than during sessions without exposure (Z = -3.79; p ≤ .001). During the exposure sessions, the participants showed significant changes in stress level (d = 0.34 - 0.87) following an inverse U-shaped trend.Conclusion: The results show that exposure is feasible within the scope of a trauma-focused group intervention for youth. The further dissemination of trauma-focused group treatments is an important component in the mental health care of traumatized children and youth.

Dopaminergic signaling supports auditory social learning

Explicit rewards are commonly used to reinforce a behavior, a form of learning that engages the dopaminergic neuromodulatory system. In contrast, skill acquisition can display dramatic improvements from a social learning experience, even though the observer receives no explicit reward. Here, we test whether a dopaminergic signal contributes to social learning in naïve gerbils that are exposed to, and learn from, a skilled demonstrator performing an auditory discrimination task. Following five exposure sessions, naïve observer gerbils were allowed to practice the auditory task and their performance was assessed across days. We first tested the effect of an explicit food reward in the observer’s compartment that was yoked to the demonstrator’s performance during exposure sessions. Naïve observer gerbils with the yoked reward learned the discrimination task significantly faster, as compared to unrewarded observers. The effect of this explicit reward was abolished by administration of a D1/D5 dopamine receptor antagonist during the exposure sessions. Similarly, the D1/D5 antagonist reduced the rate of learning in unrewarded observers. To test whether a dopaminergic signal was sufficient to enhance social learning, we administered a D1/D5 receptor agonist during the exposure sessions in which no reward was present and found that the rate of learning occurred significantly faster. Finally, a quantitative analysis of vocalizations during the exposure sessions suggests one behavioral strategy that contributes to social learning. Together, these results are consistent with a dopamine-dependent reward signal during social learning.

Dopaminergic signaling supports auditory social learning

Explicit rewards are commonly used to reinforce a behavior, a form of learning that engages the dopaminergic neuromodulatory system. In contrast, skill acquisition can display dramatic improvements from a social learning experience, even though the observer receives no explicit reward. Here, we test whether a dopaminergic signal contributes to social learning in naïve gerbils that are exposed to, and learn from, a skilled demonstrator performing an auditory discrimination task. Following five exposure sessions, naïve observer gerbils were allowed to practice the auditory task, and their performance was assessed across days. We first tested the effect of an explicit food reward in the observer’s compartment that was yoked to the demonstrator’s performance during exposure sessions. Naïve observer gerbils with the yoked reward learned the discrimination task significantly faster, as compared to unrewarded observers. The effect of this explicit reward was abolished by administration of a D1/D5 dopamine receptor antagonist during the exposure sessions. Similarly, the D1/D5 antagonist reduced the rate of learning in unrewarded observers. To test whether a dopaminergic signal was sufficient to enhance social learning, we administered a D1/D5 receptor agonist during the exposure sessions in which no reward was present, and found that the rate of learning occurred significantly faster. Finally, a quantitative analysis of observer vocalizations and movements during the exposure sessions suggest behavioral strategies that contribute to social learning. Together, these results are consistent with a dopamine-dependent reward signal during social learning.

Effects of cortisol administration on craving during in vivo exposure in patients with alcohol use disorder

Alcohol-associated memories and craving play a crucial role in the development and maintenance of alcohol use disorder (AUD). As treatment options are limited in AUD, novel treatment strategies focus on the manipulation of alcohol-associated memories. The stress hormone cortisol affects various memory processes, and first clinical studies have shown that it inhibits the retrieval of disorder-specific memories and enhances extinction memory. This study aimed to investigate the effects of a single oral administration of cortisol on craving in patients with AUD during repeated in vivo exposure to alcohol pictures and the preferred alcoholic drink. In a double-blind, block-randomized, placebo-controlled cross-over design, 46 patients with AUD were treated with two sessions of in vivo exposure to alcohol. Cortisol (20 mg) or placebo was orally administered 1 h before each test day. Craving, stress, and cortisol were repeatedly measured during exposure sessions. Results show, that cortisol administration had distinct effects on craving depending on the severity of AUD and test day. While cortisol administration significantly enhanced craving during exposure on the first test day in patients with less severe AUD, it reduced craving in patients with more severe AUD. Independent of the cortisol administration, repeated in vivo exposure reduced craving from test day 1 to test day 2. In conclusion, adding cortisol to in vivo exposure might be a promising approach for reducing the strength of alcohol-associated memories and might promote the consolidation of extinction memory in patients with severe AUD. However, the differential effect of cortisol on craving depending on AUD severity cannot be conclusively explained and highlights the need for future studies elucidating the underlying mechanism.

A new model for recovery-from-extinction effects in Pavlovian conditioning and exposure therapy

Exposure therapy is an effective intervention for anxiety-related problems. A mechanism of this intervention has been the extinction procedure in Pavlovian conditioning, and their findings have provided many effective intervention strategies that can promote the effect of and prevent relapse following exposure sessions. However, traditional associative theories that have explained Pavlovian conditioning cannot comprehensively explain their findings. In particular, it was difficult to explain the recovery-from-extinction effects, which is the reappearance of conditioned response following extinction. In this study, we propose a new associative model that can deal with procedures that promote an effect of extinction and many recovery-from-extinction effects. The cores of this model are that the asymptotic strength of the inhibitory association depends on the degree of excitatory association retrieved in a context in which CS is presented and that the retrieval is determined by the similarity between contexts during reinforcement and non-reinforcement and the present context. Moreover, this model assumes that these similarities change under specific conditions. By adding these assumptions to the traditional framework, many difficulties in explaining these phenomena can be resolved. Our model can provide not only a new perspective in associative learning, but also many implications for exposure therapy.