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.
27 December 2017: Survival-relevant decisions include avoiding starvation, and this mandates planning to maintain homeostasis across extended time horizons. In a new study in Nature Communications, Christoph Korn shows how such planning in humans combines a normatively optimal strategy with a myopic heuristic, and how discrepancies between these two control strategies are being processed neurally (Korn & Bach, Nature Communications, 2018).
04 December 2017: Matthias Staib successfully defends his PhD thesis. Congratulations!
26 November 2017: PsPM 4.0 released – including startle eye blink EMG modelling and pre-processing, and many improvements for data import and pre-processing. Thanks to everybody involved, and in particular Tobias Moser! Get the software here.
03 November 2017: Learning to predict threat requires amygdala plasticity. Sensory cortices can also be crucially required, but their role in fear acquisition remains unclear. In a recent study in Neuroimage, PhD student Matthias Staib demonstrates that Heschl’s Gyrus, including A1, represents threat predictions during fear conditioning, equally for simple and complex auditory CS. Strikingly, the representations of CS+ and CS-, respectively, are similar for simple and complex sounds, and thus invariant from the actual sound properties, likely ruling out receptive field plasticity as underlying mechanism (Staib & Bach, Neuroimage, 2017).
03 August 2017: Model-based analysis of skin conductance responses (SCR) relies on assumptions on the mapping from sudomotor nerve activity (SNA) to SCR; all existing approaches model this as a linear time-invariant (LTI) system. Together with collaborating physiologists Barbara Namer and Mikael Elam, Samuel Gerster uses intraneural recording and stimulation techniques to investigates under what conditions these assumptions are met. Indeed, when stimulation frequency is below 0.6 Hz, more than 90% of signal variability is explained under an LTI model (Gerster S, Namer B, Elam M, Bach DR, Psychophysiology 2017).
05 May 2017: Hippocampal oscillations are frequently reported in rodent approach-avoidance conflict tests of anxiety, but their expression and function in humans is not understood. In a new paper by PhD student Saurabh Khemka, we use MEG to show that hippocampal gamma power relates to learned threat probabilities under human approach-avoidance conflict. Gamma power is theta-modulated, and the hippocampus synchronises with prefrontal cortex in theta band (Khemka S, Barnes G, Dolan RJ, Bach DR, Journal of Neuroscience 2017).
28 April 2017: Amygdala-thalamus and amygdala-cortex connections are crucial for many cognitive operations, but our knowledge on these often comes from non-human research. In a new paper by Aslan Abivardi & Dominik Bach, we provide detailed quantitative in vivo analyses of white-matter connectivity between amygdala and thalamus subnuclei as well as cortical parcellations (Abivardi A & Bach DR, Human Brain Mapping 2017). A probabilistic atlas of these connections is available online here.
04 April 2017: Extracellular matrix (ECM) proteins may play a fundamental role for memory (LTP) formation, in vitro research suggests. Yet, there is little evidence from living animals, non-human or human. Strikingly, the simple antibiotic doxycycline inhibits matrix metalloproteinase (MMP) 9, which is critical for LTP, and doxycycline has been used to treat ECM disease outside the brain for at least a decade. This made it possible to test in humans to assess the impact of this MMP-9 inhibitor on fear conditioning. In a study published today, we find that a single dose of 200 mg doxycycline, ingested before fear acquisition, reduces fear retention 1 week later by around 60%, as indexed by fear-potentiated startle. This makes the drug potentially interesting for prevention or treatment of posttraumatic stress disorder (PTSD) (Bach DR, Tzovara A, Vunder J, Molecular Psychiatry 2017).
31 March 2017: Emotions have fascinated philosophers and scientists for millennia; yet there is even little consensus on what phenomena they encompass, let alone on their constituent psychological and neural mechanisms. In an opinion article for Nature Reviews Neuroscience, Dominik Bach and Peter Dayan build on decision theory to analyse emotions and reconcile diverging theories (Bach DR & Dayan P, Nature Reviews Neuroscience 2017)
03 February 2017: During anticipation of a probabilistic reward, where and how are statistics of the reward distribution computed? In our latest paper, we use MEG to address the temporal evolution of this encoding, both for expected reward and its variability. Beyond regions previously known to encode such statistics (such as OFC), we find a surprisingly early and robust encoding in visual and polymodal parietal areas, unexplained by visual features of the predictive stimuli (Bach DR, Symmonds M, Barnes G, Dolan RJ, in press, Journal of Neuroscience).
02 February 2017: Approach/avoidance conflict has been proposed as experimental model of human anxiety-like behaviour, and is sensitive to hippocampus lesions as in animals. In a new paper, Christoph Korn and colleagues show that this model is also sensitive to the anxiolytic drug lorazepam, thus highlighting the validity of the set up. Furthermore, by investigating two rare patients with Urbach-Wiethe disease, they find that selective amygdala lesions and hippocampus have a similar impact on the game, acting like a strong anxiolytic (Korn CK, Vunder J, Miro J, Fuentemilla L, Hurlemann R, Bach DR, in press, Biological Psychiatry).
19 January 2017: For us, 2016 was the year of Psychophysiological Modelling – with 7 research papers on methods & models development. In 2017, we will demonstrate how these methods (and our ethobehavioural computer games) can be used to tackle neuroscience questions.