17 January 2020: Using intuition to design informative experiments, which allow accurate statistical inferences, is challenging. This is especially true in fields where there has been a proliferation of increasingly complex theoretical models. The study of associative learning provides an example of such a field (e.g., see Tzovara et al. 2018). In a new paper, we propose for associative learning experiments to be algorithmically optimized. Through simulations we show that optimized experiments may provide substantially improved statistical inferences. Due to the generality of the simulation-based experimental design framework, the proposed approach may also be useful in other learning and decision making experimental domains (Melinscak & Bach 2020, PLOS Computational Biology).
12 December 2019: Christmas dinner in Zurich – this year enjoying Chinese food while commencing to wind down after a year’s hard work. We also welcomed our new study coordinator Aneta and administrative assistant Ilona who started with us in November.
4 November 2019: We migrated PsPM to GitHub and released version 4.2.1 – including various changes to increase ease of use, several bugfixes and new tests . Thanks to everybody involved, in particular Eshref Yozdemir! Get the software here.
09 October 2017: Classically, amygdala and thalamus are required to learn threat predictions, without a necessary role for cortex. However, some rodent research suggests that to discriminate threat-predicting cues from cues predicting safety, sensory cortex is required. We have recently shown that Heschl’s gyrus in human auditory cortex represents threat associations, over and above the physical difference between threat- and safety-predicting cues, both for physically simple (monophone) and complex (spatiotemporal patterns) sounds. Here, we replicate this finding for a different class of sounds without temporal discriminative features, and confirm it is restricted to primary auditory cortex within Heschl’s gyrus (Staib et al. 2019, Human Brain Mapping, in press). In ongoing work, we seek to establish whether these representations are causally required for threat learning.
17 September 2019: Last Wednesday, September 11th, our traditional Summer BBQ took place – this time together with our three partner labs (CRPP Synapse & Trauma). We spent a cheerful evening with colleagues and friends at the nearby Quartierhof Wynegg. Ahead of the official part of the evening we said goodbye to our PhD Student, Karita Ojala, who sadly leaves us after three years’ time as well as to Lena Rhonheimer, our Student Research Assistant for the past year. Thank you both for your commitment – it was a pleasure having you in our team! We wish you all the best for the future and a lot of success with your endeavours!
16 September 2019: PsPM 4.2.0 released – including new pupil preprocessing, pupil foreshortening error correction and QRS detection algorithms; performance optimizations to pupil data import functions; new tests, bugfixes and changes to the behaviour of some functions to make PsPM more uniform and easier to use. Thanks to everybody involved! Get the software here.
12 September 2019: MMP-9 inhibition appears to attenuate memory consolidation (see our previous paper: (Bach et al 2018, Molecular Psychiatry). It could also be a target for blocking reconsolidation. In a new paper, we tested this hypothesis in human threat conditioning. We find that doxycycline has no specific impact on a reminded cue, but confers a global reduction in extinction learning and threat learning beyond the clearance of the drug. This may point towards a more long-lasting impact of doxycycline treatment on memory plasticity (Bach et al. 2019b, Journal of Neuroscience).
02 September 2019: Approach-avoidance conflict behaviour requires anterior hippocampus, and in a range of tests also amygdala. Most of these tests require a number of individual actions, and which of these rely on hippocampus or amygdala is unclear. In a clinical lesion study together with our colleagues at the Charité Department of Neurology in Berlin, we show that human hippocampus lesions impair the decision to stay away from reward when danger is high, but leave swift escape from threat intact. Amygdala lesions, in contrast, do not impair the decision to stay away from report but markedly increase the vigour of escape from threat (Bach et al. 2019a, Journal of Neuroscience).
14 August 2019: Dominik Bach has accepted an appointment as Principal Research Fellow at the UCL Queen Square Institute of Neurology, University College London. He will be joining the Max-Planck/UCL Centre for Computational Psychiatry and Ageing Research, and the Wellcome Centre for Human Neuroimaging, as a Principal Investigator later in the year, while research activities continue in Zurich.
11 July 2019: Many ethological approach-avoidance conflict tests do not allow separating different action components. This impedes investigation whether they are under the same or dissociable neural control. We have previously developed a human computer game to separate action components (Bach 2015 PLOS CB). Here, our collaborators at Platrad build on this idea and present a novel 2-lever approach-avoidance conflict test for mice that separates decision to approach, approach latency, and approach vigour (Oberrauch et al., 2019, Psychopharmacology).
04 July 2019: Magnetoencephalography (MEG) measures the magnetic field emitted by the brain and allows reconstructing the underlying neural activity. For deep sources such as the amygdala, it has been unclear whether what appears as source activity is really coming from this source, or from nearby areas. In this new paper, Athina Tzovara and colleagues at UZH and UCL record high-precision MEG. They then show that the measured data can be better explained with reconstruction models that allow for sources in the amygdala than for models that do not. Furthermore, just moving this anatomical location by 3 mm made the explained variance drop decisively. This demonstrates the spatial precision of the method. They then analyse amygdala source data during threat conditioning and find a pattern that is rather different from what is commonly observed in short rodent experiments (Tzovara et al., 2019 Human Brain Mapping).
17 June 2019: PsPM 4.1.1 released – including new models and data processing methods, support for two new eye tracker formats, various improvements and bugfixes. Thanks to everybody involved! Get the software here.
4 June 2019: In this new article, the CRPP PIs Dominik Bach, Steven Brown, Birgit Kleim and Shiva Tyagarajan, review evidence for roles of the extracellular matrix in learning and memory, and in experience-dependent psychiatric conditions. They then suggest how control of the extracellular matrix could be leveraged for innovative treatments and discuss possible aetiological mechanisms of extracellular matrix alterations in psychiatric disorders. Swiss Medical Weekly, 149:w20060.
2 May 2019: In a new paper, Christoph Korn investigates how humans decide to forage under combined risk of starvation and predation in an virtual approach-avoidance conflict task (Korn & Bach, 2019, Nature Human Behaviour). He shows that participants rely both on predator probability, and on the normatively optimal policy. Predator probability was related to BOLD signals in hippocampus and amygdala. The optimal policy was related to medial prefrontal cortex.
23 April 2019: Human threat learning measures mostly rely on psychophysiological responses (e.g. SCR, respiration responses, ECG, pupillary responses…). In a newly published article, Yanfang Xia, Angelina Gurkina and Dominik Bach adapt an existing Pavlovian-to-Instrumental transfer (PIT) paradigm with modifications in reinforcers to demonstrate conditioned facilitation of formally unrelated instrumental avoidance behavior in humans. They also apply this PIT measure as an additional novel behavioral human threat learning measure (Xia, Gurkina & Bach, Learning & Memory, 2019).
27 March 2019: Launch of the CRPP Synapse & Trauma Website https://www.synapsetrauma.uzh.ch/en.html
26 March 2019: Professor Raffael Kalisch gives talk on the exciting topic of resilience at the Psychiatric Hospital Zurich: Resilience – it’s not what you think it is.
29 November 2018: ERC Consolidator Grant for Dominik Bach. The European Research Council (ERC) funds the project “Action Selection under Threat – the Complex Control of Human Defence (ActionContraThreat)” with 2 Million Euro. With this grant, Dominik Bach will study how humans coordinate a rich and sophisticated behavioural repertoire when in acute danger, such as from other humans, predating animals, or natural disaster. He will use virtual reality, motion capture, and magnetoencephalography to expose the mechanisms by which motor behaviour is computed and controlled.
04 July 2018: Dominik Bach is laureate of this year’s Robert Bing Prize from the Swiss Academy of Medical Sciences. More information here. Thanks to the great team who made this possible!
16 June 2018: Several non-benzodiazepine anxiolytics have been developed and tested and rodents, and not made it to clinical application. Here, we use our lorazepam-validated approach-avoidance computer game to elicit anxiety-like behaviour and test the impact of a potential anxiolytic, the antiepileptic drug valproate, against an established anxiolytic, pregabalin. The two drugs have very similar effects, which could potentially motivate clinical trials (Bach et al., Translational Psychiatry, 2018).
15 June 2018: Human fear conditioning has been described to follow classical reinforcement learning rules. In a new article, Athina Tzovara uses PsPM to recover ANS input into sweat-gland (SCR) and pupil system during fear conditioning. Rather than by classic RL models, ANS activity is best explained by a probabilistic learning model that accounts for uncertainty in the threat (US) estimation. Furthermore, SCR and pupil map onto different learning quantities: pupil size reflects estimate US probability, but SCR reflects a combination of this and the uncertainty of the estimate (Tzovara, Korn & Bach, PLOS Computational Biology, 2018).
14 June 2018: University of Zurich funds a 3-year Clinical Research Priority Program (CRPP) “Synapse & Trauma” with 1.75 MCHF to look into synaptic plasticity interventions for treatment of trauma memory. PIs are Dominik Bach, Steven Brown, Shiva Tyagarajan, Birgit Kleim. We will be hiring 6 PhD and MD/PhD students – more information here.
16 May 2018: Psychophysiological modelling is an emerging technique to analyse peripheral physiology in behavioural research (SCR, ECG, respiration, pupil, breathing, EMG, …). A new review now summarises the theoretical and statistical background, as well as all methods that have been developed by ourselves and other groups (Bach et al., Psychophysiology, 2018).
06 April 2018: PsPM 4.0.2 is released with further minor bug fixes.
09 March 2018: Giuseppe Castegnetti successfully defends his PhD thesis. Congratulations!
07 March 2018: We are running a PsPM workshop a the Meeting of the German Psychological Society/Section Biological Psychology (Psychologie & Gehirn). Information and registration can be found here.
23 February 2018: PsPM 4.0.1 is released with minor bug fixes.