Biology subjects

Olsson, A.

Publications and source records attributed to Olsson, A..

24 records · Page 2Linked to original sources

bioRxiv2020

Causes of death in newborn C57BL/6J mice

Neonatal mortality in wild-type laboratory mice is an overlooked welfare and financial problem in animal facilities around the world. Causes of death are often not reported and its causes remain unknown. In this study, 324 newborn pups from two breeding colonies of healthy wildtype C57BL/6 mice underwent post-mortem analysis with special focus on obtaining proof of life after birth, evaluation of stomach contents and observation of congenital abnormalities that could compromise survival. Based on a combination of lung morphology findings, outcome of lung float test, stomach contents and brown adipose tissue colouration, 21.6% of the pups found dead were considered stillbirths. Of the livebirths, only 3.2% were observed to have milk inside the stomach, indicating successful suckling. Congenital abnormalities were diagnosed only in a small fraction of the pups analysed. These results suggest that starvation was the most common cause of death, followed by stillbirth.

pathology↗

bioRxiv2020

Observed but Never Experienced - Vicarious Learning of Fear Under Ecological Conditions

Learning to avoid threats often occurs by observing the behavior of others. Most previous research on observational fear learning in humans has used pre-recorded stimuli as social cues. Here, we aimed to enhance the ecological validity of the learning situation: the observer watched their friend ( demonstrator) performing a differential fear-conditioning task in real time. During the task, one conditioned stimulus (CS+) was repeatedly linked with electric stimulation (US) while another one (CS-) was always safe. Subsequently, the observer was presented with the CS+ and CS- directly but without receiving any shocks. Skin conductance (SCR) and fear-potentiated startle (FPS) responses were measured in observers throughout the whole experiment. While the US applied to the demonstrator elicited strong SCR in the observers, subsequent differential SCR to CSs (CS+ vs. CS-) presented directly were dependent on declarative knowledge of the CS+/US contingency. Contingency-aware observers also showed elevated FPS during both CS+ and CS- compared to intertrial intervals. We conclude that observational fear learning involves two components: an automatic emotional reaction to the response of the demonstrator and learning to predict stimulus contingency (CS+/US pairing). Ecological modifications proposed offer new perspectives on studying social learning of emotions.

neuroscience↗

bioRxiv2019

Does training method matter?: Evidence for the negative impact of aversive-based methods on companion dog welfare

There is a growing number of dogs kept as companion animals, and the methods by which they are trained range broadly from those using mostly positive punishment and negative reinforcement (aversive-based methods) to those using primarily positive reinforcement (reward-based methods). Although the use of aversive-based methods has been strongly criticized for negatively affecting dog welfare, these claims do not find support in solid scientific evidence. Previous research on the subject lacks companion dog-focused research, investigation of the entire range of aversive-based techniques (beyond shock-collars), objective measures of welfare, and long-term welfare studies. The aim of the present study was to perform a comprehensive evaluation of the short- and long-term effects of aversive- and reward-based training methods on companion dog welfare. Ninety-two companion dogs were recruited from three reward-based (Group Reward, n=42) and four aversive-based (Group Aversive, n=50) dog training schools. For the short-term welfare assessment, dogs were video recorded for three training sessions and six saliva samples were collected, three at home (baseline levels) and three after the training sessions (post-training levels). Video recordings were then used to examine the frequency of stress-related behaviors (e.g., lip lick, yawn) and the overall behavioral state of the dog (e.g., tense, relaxed), and saliva samples were analyzed for cortisol concentration. For the long-term welfare assessment, dogs performed a cognitive bias task. Dogs from Group Aversive displayed more stress-related behaviors, spent more time in tense and low behavioral states and more time panting during the training sessions, showed higher elevations in cortisol levels after training and were more pessimistic in the cognitive bias task than dogs from Group Reward. These findings indicate that the use of aversive-based methods compromises the welfare of companion dogs in both the short- and the long-term.

animal behavior and cognition↗

bioRxiv2019

Oxazepam and cognitive reappraisal: a randomised experiment

BackgroundCognitive reappraisal is a strategy for emotional regulation, important in the context of anxiety disorders. It is not known whether anxiolytic effects of benzodiazepines affect cognitive reappraisal. AimsWe aimed to investigate the effect of 25 mg oxazepam on cognitive reappraisal. MethodsIn a preliminary investigation, 33 healthy male volunteers were randomised to oxazepam or placebo, and then underwent an experiment where they were asked to use cognitive reappraisal to upregulate or downregulate their emotional response to images with negative or neutral emotional valence. We recorded unpleasantness ratings, skin conductance, superciliary corrugator muscle activity, and heart rate. Participants completed rating scales measuring empathy (Interpersonal Reactivity Index, IRI), anxiety (State-Trait Anxiety Inventory, STAI), alexithymia (Toronto Alexithymia Scale-20, TAS-20), and psychopathy (Psychopathy Personality Inventory-Revised, PPI-R). ResultsUpregulation to negative-valence images in the cognitive reappraisal task caused increased unpleasantness ratings, corrugator activity, and heart rate compared to downregulation. Upregulation to both negative- and neutral-valence images caused increased skin conductance responses. Oxazepam caused lower unpleasantness ratings to negative-valence stimuli, but did not interact with reappraisal instruction on any outcome. Self-rated trait empathy was associated with stronger responses to negative-valence stimuli, whereas self-rated psychopathic traits were associated with weaker responses to negative-valence stimuli. ConclusionsWhile 25 mg oxazepam caused lower unpleasantness ratings in response to negative-valence images, we did not observe an effect of 25 mg oxazepam on cognitive reappraisal.

neuroscience↗

bioRxiv2018

Physiological Synchrony Predicts Observational Threat Learning in Humans

Understanding how information about threats in the environment is shared and transmitted between individuals is crucial for explaining adaptive, survival-related behavior in humans and other animals, and for developing treatments for phobias and other anxiety disorders. Research across species has shown that observing a conspecifics, a "demonstrators", threat responses causes strong and persistent threat memories in the "observer". Here, we examined if physiological synchrony between demonstrator and observer can serve to predict the strength of observationally acquired conditioned responses. We measured synchrony between demonstrators and observers phasic electrodermal signals during learning, which directly reflects autonomic nervous system activity. Prior interpersonal synchrony predicted the strength of the observers later skin conductance responses to threat predicting stimuli, in the absence of the demonstrator. Dynamic coupling between an observers and a demonstrators autonomic nervous system activity may reflect experience sharing processes facilitating the formation of observational threat associations.

neuroscience↗

bioRxiv2018

Enhanced instructed fear learning in delusion-proneness

Psychosis is characterized by distorted perceptions and deficient low-level learning, including reward learning and fear conditioning. This has been interpreted as reflecting imprecise priors in a predictive coding system. However, this idea is not compatible with formation of overly strong beliefs and delusions in psychosis-associated states. A reconciliation of these paradoxical observations is that these individuals actively develop and use higher-order beliefs in order to interpret a chaotic environment. In the present behavioural and fMRI study, we compared delusion-prone individuals (n=20), a trait related to psychotic disorders, with controls (n=23; n=20 in fMRI-part) to study the effect of beliefs on fear learning. We show that instructed fear learning, involving explicit change of beliefs and an associated activation of lateral orbitofrontal cortex, is expressed to a higher degree in delusion-prone subjects. Our results suggest that strong high-level top-down learning co-exists with previously reported weak low-level bottom-up learning in psychosis-associated states.

physiology↗