News from the Lab
2024
02 April: We welcomed Sara Ershadmanesh as a postdoctoral fellow to our team in Bonn. She will be working on our ActionContraThreat project.
29 February: Fear conditioning is a commonly used learning model with clinical relevance. Quantification of threat conditioning in humans often relies on conditioned autonomic responses, such as skin conductance responses (SCR), pupil size responses (PSR), heart period responses (HPR), or respiration amplitude responses (RAR), which are usually analyzed separately. In a mega-analytic approach, we re-analyze nine data sets, including more than 250 individuals, using standard routines in the framework of psychophysiological modeling (PsPM). We derive and provide the statistically optimal weights for combining the four measures and subsets thereof, and further provide out-of-sample performance metrics for these weights, accompanied by bias-corrected confidence intervals. We show that combining measures allows for a relevant reduction in sample size, averaging at circa 24%. We also demonstrate a one-dimensional structure of threat conditioning measures and systematic differences in effect size between measures. Read the open-access article here.
15 Febuary: Today, we welcomed Moumita Das as a guest researcher to our team in Bonn.
09 February: New article published in Psychopharmacology. We studied the effect of doxycycline on configural fear conditioning in a double-blind placebo-controlled randomised trial with healthy human participants. Our results suggest that doxycycline does not substantially attenuate contextual fear memory. This might limit its potential for clinical application. However, in a different study we showed that the chemically related substance minocycline attenuates contextual fear memory in the same paradigm (in fact, doxycycline was significantly directly inferior to minocycline in a direct comparison, unpublished data). More details in the open-access article: Xia, Wehrli, et al. (2024b) [Open Data]
01 February: We welcomed Jonas Zimmer as a postdoctoral fellow to our team in Bonn. He will be working on the development of digital twins for virtual reality environments, part of the "InVirtuo 4.0" project.
17 January 2024: New article published in Nature Translational Psychiatry on "single-dose minocycline-induced attenuation of fear memory retention". In this pre-registered, randomised, double-blind, placebo-controlled trial with N = 105 healthy participants (N = 70 female), we used a configural fear conditioning paradigm and investigated the effect of the tetracycline antibiotic minocycline, an inhibitor of matrix metalloproteinase 9 (MMP-9), on fear memory retention. We administered a single dose of 200-mg minocycline before configural fear memory acquisition and assessed fear memory retention seven days later in a recall test. Our pre-registered primary outcome, fear-potentiated startle (FPS), revealed attenuated retention of configural fear memory in individuals treated with minocycline compared to placebo. In contrast, minocycline did not affect fear memory acquisition, as measured by skin conductance responses and pupil dilation, or declarative contingency memory. More details in the open-access article: Xia, Wehrli, et al. (2024a) [Open Data] [Open Code]
2023
26 December 2023: Measurement methods ought to be validated, but in experimental research this is far from trivial. This is because all quantitative validity or reliability coefficients require stable between-person variance, whereas in experimental research, between-person variance is regarded as noise and researchers strive to minimise it as much as possible. This can lead to the paradoxical situation depicted in the figure: one measurement method clearly separates experimental conditions but has zero reliability, whereas another method with high reliability does not separate experimental conditions very well. In this new theoretical note, we discuss these and other issues in simulated examples, and show how experiment-based calibration can solve them. Read the open-access article here.
08 November 2023: New paper published in Journal of Mathematical Psychology. Experiment-based calibration is a novel method for evaluating and comparing the accuracy of measurement methods in psychological, cognitive, and behavioural sciences. This new article analyzes how to best design calibration experiments in order to maximise the information gain. Through mathematical analysis and numerical simulations, several recommendations are derived for the design of calibration experiments. In a nutshell, this calls for equiprobable standard values, many participants, and good theories to start with.
Read the open-access article here. Open code available on OSF: https://osf.io/dfg9e/
08 November 2023: New published paper on “the functional sophistication of human escape”. We investigated naturalistic escape decisions in fully-immersive VR with 13 bio-realistic threats. While escape from immediate attack is often seen as a “fight or flight response”, we showed that escape decisions can adapt dynamically. Goals can integrate factors like time-to-impact with threat characteristics such as attack probability (feral vs. domestic) and expected trajectory (pursuit vs. ballistic interception). The way participants executed their escape varied depending on the threat's speed, time-to impact, and other factors. It was an energy-efficient and goal-oriented process, showing adaptability. Regarding the computational characteristics of escape decisions, perturbance experiments showed that the underlying decision algorithm exhibits planning properties and can integrate novel actions. In contrast, rapid information-seeking and foraging-suppression are only partly devaluation-sensitive. Additionally, the study revealed that stable personal traits like fearfulness, fear of spider, and gender influenced escape initiation time, as well as distance from the threat. Individual differences played a significant role in escape decisions, as it explained around 30% of the between-person variance. To ensure replicability, our results are based on exploration-confirmation approach and all data, code, and the VR games are available on OSF here. Read the full article here: Sporrer S, Brookes J, Hall S et al. (2023).
01 November 2023: We welcomed Patrick Harder as the new lab manager, and Yaxin Liu as a postdoctoral fellow to our team in Bonn.
15 October 2023: Today, we welcome Olivier de Vries as a postdoctoral fellow to our team in Bonn.
04 October 2023: In this new article, we present the conceptual design of a novel immersive VR toolkit for the Unity engine that allows assessing threat-related behaviour in single, semi-interactive, and semi-realistic threat encounters. The toolkit contains a suite of fully modelled naturalistic environments, interactive objects, animated threats, and scripted systems. With this software, we aim to facilitate the use of immersive VR in human threat avoidance research and thus to close a gap in the understanding of human behaviour under threat. Access more details in the open-access article and check out our VRthreat Toolkit for Unity to build your own serious games to probe human escape & avoidance behaviour: Brookes J, Hall S, Frühholz S. et al. (2023).
Figure: Game design by Jack Brookes with beautiful graphics by Samson Hall.
01 October 2023: Today, we welcome Sourav Kulkarni as a research assistant to our team in Bonn.
27-29 September 2023: We had a great time at our first lab retreat in Ostend last week. Three days on the Belgian seaside, full of team-building activities and workshopping with both teams - UCL and Uni Bonn together. Thanks to everybody, who joined!
04 September 2023: New study published - Deviant sounds are a signal of potential threat in natural environments, activating the locus coeruleus (LC)-mediated attention system. While amygdala is known to modulate attention to salient stimuli and exhibits dense connections with LC, studies on LC-amygdala interaction during anomalous sound detection have been sparse. In this new study, we measured pupillary dilation, a proxy of LC activity, and used PsPM to infer the shape of neural responses during auditory oddball detection. We investigate a rare human case of bilateral amygdala lesion (due to Urbach-Wiethe syndrome) and 23 matched controls. Strikingly, we found that estimated LC activity during oddball detection was compacted to an impulse shape in the patient only, suggesting that sustained activity in LC might be contingent upon its communication with amygdala. For an in-depth exploration, access our full article here.
Figure caption (right): Estimated neural responses (red), inferred via PsPM from pupil recordings, exhibited a distinct impulse-like form in the patient with bilateral amygdala lesion (BG) and an earlier mean than in all matched controls.
30 August 2023: Team dinner at UCL, where we had to say goodbye to our research assistant Marina Rodrigues Lopez after almost two years. We took the opportunity to wish her all the best for her PhD in Cambridge, and to welcome her successor Josie Linnell in the ERSC-funded CogLearn project.
24 August 2023: PsPM version 6.1.0 released. Thanks to everybody involved! Get the software here.
08 August 2023: New article published - Fear conditioning is a laboratory paradigm commonly used to investigate aversive learning and memory. In context fear conditioning, a configuration of elemental cues (conditioned stimulus, CTX) predicts an aversive event (unconditioned stimulus, US). In the current work, we wanted to find out how to best elicit and measure context conditioning, and its retention over 7 days. In four experiments, we tested a semi-immersive virtual reality paradigm, and a configural fear conditioning paradigm with static room images. Declarative memory was established in all experiments. Surprisingly, there were no detectable and consistent conditioned responses in the two VR experiments. In contrast, we found medium effect sizes to distinguish CTX+ from CTX- in the configural paradigm: larger SCR and pupil dilation to CTX+ onset during acquisition training, and larger SEBR and pupil dilation to CTX+ during the recall test. More details in the open-access article: Xia et al. (2023). [Open Data 1] [Open Data 2] [Open Data 3] [Open Data 4] [Open Code]
09 July 2023: Two members of our lab participated in the science slam segment at University of Bonn's science fair. You could find us at the booth of the Transdisciplinary Research Area "Life and Health". Visitors could also gain insight in our current work at the VR lab through a short video clip that premiered that day. Find it on YouTube here.
24 May 2023: We participated in Uni Bonn’s dies academicus and opened our lab to the public. We had a fun day showing our brand new VR lab - thanks to all visitors for your interest and enthusiasm!
22 May 2023: The homepage of the Hertz Chair for Artificial Intelligence and Neuroscience at the University of Bonn (this website) went live.
04 May 2023: The Wellcome Centre for Human Neuroimaging at UCL has been awarded substantial funding from Wellcome to establish a Discovery Research Platform for Naturalistic Neuroimaging. This platform will create a unique facility with transformative imaging technology, novel experimental designs and innovative analytics, all dedicated to studying how the human brain engages with the real world. It aims to provide new perspectives on the diagnosis and treatment of neurological and mental health conditions. We are thrilled to be involved and to contribute to this project.
17 April 2023: Today, we welcome Uzay Gökay as a doctoral fellow to our team in Bonn.
27 March 2023: New article published - Fear conditioning is a widely used laboratory model to investigate learning, memory, and psychopathology across species. The quantification of learning in this paradigm is heterogeneous in humans and psychometric properties of different quantification methods can be difficult to establish. To overcome this obstacle, calibration is a standard metrological procedure. In this article, we develop a calibration protocol for human fear conditioning, based on literature review, a series of workshops, and a survey of 96 experts. More details in the article (open access!). Bach et al. (2023).
2022
09 December 2022: Congratulations to Yanfang Xia who successfully defended her PhD thesis at UZH today!
01 October 2022: We welcome Yanfang Xia, who moved from Zurich to Bonn, and Huaiyu Liu as a postdoctoral researcher to our team at UCL, who will work in the ESRC-funded project “A cognitive-computational model of avoidance learning”. After wrapping up the initial phase of the CRPP “Synapse & Trauma” , our affiliation with University of Zurich has now ended.
25 September 2022: Today was the day of Professor Dominik Bach’s Inaugural Symposium “Circuits for Survival”. If you took the opportunity to attend the lectures, we hope you enjoyed the program. The report is now available online on the website of the Transdisciplinary Research Area “Life and Health”. Read more about the symposium here.
Pictured on the left: Speakers at the symposium. From left to right: Jason Kerr (Max Planck Institute for Neurobiology of Behavior), Peter Dayan (Max Planck Institute for Biological Cybernetics), Dominik Bach (University of Bonn), Benjamin Grewe (ETH Zurich), Vanessa Stempel (Max Planck Institute for Brain Research), and Bianca A. Silva (Consiglio Nazionale di Ricerche).
24 September 2022: Team members of all three research locations – Bonn, London, and Zurich – got together in Bonn. In anticipation of the symposium, and a workshop on the following day, the teams met for the first time for dinner on Sunday night.
15 September 2022: Today, we welcome Lukas Kornemann as a doctoral fellow to our team in Bonn. He will work on human escape response in the context of the ERC project “ActionContraThreat”.
06 September 2022: We are delighted to announce, the inaugural lecture of Prof. Dr. Dr. Dominik Bach as the Hertz Chair for Artificial Intelligence and Neuroscience at University of Bonn on 26 September 2022. The lecture will be part of “Circuits for Survival”, a symposium with renowned speakers organized by the Transdisciplinary Research Area “Life and Health” of Bonn University.
20 August 2022: New article published – Survival in biological environments requires learning associations between predictive sensory cues and threatening outcomes. Such aversive learning may be implemented through reinforcement learning algorithms that are driven by the signed difference between expected and encountered outcomes, termed prediction errors (PEs). While PE-based learning is well established for reward learning, the role of putative PE signals in aversive learning is less clear. Here, we used functional magnetic resonance imaging in humans to investigate the neural representation of PEs during maintenance of learned aversive associations. Surprisingly, we find clear PE representations for US omission but not for US presence.
More details in the article (open access!). Ojala et al. (2022).
15 August 2022: Today, we welcome Yonatan Hutabarat as postdoctoral fellow to our team in Bonn. He will work on the structure of threat-related movements in the context of the ERC project “ActionContraThreat”.
01 August 2022: Today Federico Mancinelli joined us at University of Bonn as postdoctoral fellow, where he will work on cognitive-computational models of threat avoidance in the context of the CogLearn project. We also welcomed Merle Ingenfeld as research coordinator to the team.
17 July 2022: We welcome Sascha Bonneschranz as lab manager to our team in Bonn.
16 July 2022: PsPM 6.0.0 released – including developer mode, gaze signal post processing, specific lateral or combined pupil data processing, improved file overwriting behaviour, supporting PPG data loading, various bug fixes and improvements for functions, and more. Thanks to everybody involved! Get the software here.
04 March 2022: New article by our collaborators in Oslo - Trends and opportunities for measurement of electrodermal activity. A review on the history and basic physiology of EDA, novel technologies such as wearables, and novel analysis strategies such as psychophysiological modelling, machine learning and sensor fusion. More details in the article here.