Trauma film viewing and intrusive memories: Relationship between salivary alpha amylase, endocannabinoids, and cortisol.

The endogenous cannabinoid (ECB) system is a small molecule lipid signalling system that is involved in stress response activation and is associated with PTSD, but it is unclear whether salivary ECBs are part of the sympathetic nervous system response to stress. We conducted an adapted trauma film paradigm, where participants completed a cold pressor test (or control) while watching a 10-minute trauma film. We also collected saliva and hair samples and tested them for ECBs, cortisol, and salivary alpha amylase (sAA). As hypothesised, there were significant positive correlations between sAA activity and salivary ECB levels, particularly 2-arachidonoyl glycerol (2-AG), though ECBs were not correlated with sAA stress reactivity. Participants who had a significant cortisol response to the trauma film/stressor reported less intrusive memories, which were also less distressing and less vivid. This effect was moderated by arachidonoyl ethanolamide (AEA), where decreases in AEA post-stress were associated with more intrusive memories in cortisol non-responders only. This study provides new evidence for the role of ECBs in the sympathetic nervous system.

Real-time monitoring of Ti(IV) metal ion binding of transferrin using a solid-state nanopore.

Transferrin, a central player in iron transport, has been recognized not only for its role in binding iron but also for its interaction with other metals, including titanium. This study employs solid-state nanopores to investigate the binding of titanium ions [Ti(IV)] to transferrin in a single-molecule and label-free manner. We demonstrate the novel application of solid-state nanopores for single-molecule discrimination between apo-transferrin (metal-free) and Ti(IV)-transferrin. Despite their similar sizes, Ti(IV)-transferrin exhibits a reduced current drop, attributed to differences in translocation times and filter characteristics. Single-molecule analysis reveals Ti(IV)-transferrin's enhanced stability and faster translocations due to its distinct conformational flexibility compared to apo-transferrin. Furthermore, our study showcases solid-state nanopores as real-time monitors of biochemical reactions, tracking the gradual conversion of apo-transferrin to Ti(IV)-transferrin upon the addition of titanium citrate. This work offers insights into Ti(IV) binding to transferrin, promising applications for single-molecule analysis and expanding our comprehension of metal-protein interactions at the molecular level.

Audiovisual spatial ventriloquism is reduced in musicians.

There is great scientific and public interest in claims that musical training improves general cognitive and perceptual abilities. While this is controversial, recent and rather convincing evidence suggests that musical training refines the temporal integration of auditory and visual stimuli at a general level. We investigated whether musical training also affects integration in the spatial domain, via an auditory localisation experiment that measured ventriloquism (where localisation is biased towards visual stimuli on audiovisual trials) and recalibration (a unimodal localisation aftereffect). While musicians (n = 22) and non-musicians (n = 22) did not have significantly different unimodal precision or accuracy, musicians were significantly less susceptible than non-musicians to ventriloquism, with large effect sizes. We replicated these results in another experiment with an independent sample of 24 musicians and 21 non-musicians. Across both experiments, spatial recalibration did not significantly differ between the groups even though musicians resisted ventriloquism. Our results suggest that the multisensory expertise afforded by musical training refines spatial integration, a process that underpins multisensory perception.

The next frontier: Moving human fear conditioning research online.

Fear conditioning is a significant area of research that has featured prominently among the topics published in Biological Psychology over the last 50 years. This work has greatly contributed to our understanding of human anxiety and stressor-related disorders. While mainly conducted in the laboratory, recently, there have been initial attempts to conduct fear conditioning experiments online, with around 10 studies published on the subject, primarily in the last two years. These studies have demonstrated the potential of online fear conditioning research, although challenges to ensure that this research meets the same methodological standards as in-person experimentation remain, despite recent progress. We expect that in the coming years new outcome measures will become available online including the measurement of eye-tracking, pupillometry and probe reaction time and that compliance monitoring will be improved. This exciting new approach opens new possibilities for large-scale data collection among hard-to-reach populations and has the potential to transform the future of fear conditioning research.

Use of a solid-state nanopore for profiling the transferrin receptor protein and distinguishing between transferrin receptor and its ligand protein.

A nanopore device is capable of providing single-molecule level information of an analyte as they translocate through the sensing aperture-a nanometer-sized through-hole-under the influence of an applied electric field. In this study, a silicon nitride (Six Ny )-based nanopore was used to characterize the human serum transferrin receptor protein (TfR) under various applied voltages. The presence of dimeric forms of TfR was found to decrease exponentially as the applied electric field increased. Further analysis of monomeric TfR also revealed that its unfolding behaviors were positively dependent on the applied voltage. Furthermore, a comparison between the data of monomeric TfR and its ligand protein, human serum transferrin (hSTf), showed that these two protein populations, despite their nearly identical molecular weights, could be distinguished from each other by means of a solid-state nanopore (SSN). Lastly, the excluded volumes of TfR were experimentally determined at each voltage and were found to be within error of their theoretical values. The results herein demonstrate the successful application of an SSN for accurately classifying monomeric and dimeric molecules while the two populations coexist in a heterogeneous mixture.

Musical training refines audiovisual integration but does not influence temporal recalibration.

When the brain is exposed to a temporal asynchrony between the senses, it will shift its perception of simultaneity towards the previously experienced asynchrony (temporal recalibration). It is unknown whether recalibration depends on how accurately an individual integrates multisensory cues or on experiences they have had over their lifespan. Hence, we assessed whether musical training modulated audiovisual temporal recalibration. Musicians (n = 20) and non-musicians (n = 18) made simultaneity judgements to flash-tone stimuli before and after adaptation to asynchronous (± 200 ms) flash-tone stimuli. We analysed these judgements via an observer model that described the left and right boundaries of the temporal integration window (decisional criteria) and the amount of sensory noise that affected these judgements. Musicians' boundaries were narrower (closer to true simultaneity) than non-musicians', indicating stricter criteria for temporal integration, and they also exhibited enhanced sensory precision. However, while both musicians and non-musicians experienced cumulative and rapid recalibration, these recalibration effects did not differ between the groups. Unexpectedly, cumulative recalibration was caused by auditory-leading but not visual-leading adaptation. Overall, these findings suggest that the precision with which observers perceptually integrate audiovisual temporal cues does not predict their susceptibility to recalibration.

Angry and fearful compared to happy or neutral faces as conditional stimuli in human fear conditioning: A systematic review and meta-analysis.

Some previous research has shown stronger acquisition and impaired extinction of fear conditioned to angry or fearful compared to happy or neutral face conditional stimuli (CS) - a difference attributed to biological 'preparedness'. A systematic review and meta-analysis of fear conditioning studies comparing face CSs of differing expressions identified thirty studies, eighteen of which were eligible for meta-analysis. Skin conductance responses were larger to angry or fearful faces compared to happy or neutral faces during habituation, acquisition and extinction. Significant differences in differential conditioning between angry, fearful, neutral, and happy face CSs were also found, but differences were more prominent between angry and neutral faces compared to angry/fearful and happy faces. This is likely due to lower arousal elicited by neutral compared to happy faces, which may be more salient as CSs. The findings suggest there are small to moderate differences in differential conditioning when angry or fearful compared to happy or neutral faces are used as CSs. These findings have implications for fear conditioning study design and the preparedness theory.