We have recently published a new paper in PNAS, which investigates how the brains learns about different choice-relevant features, such as effort and reward. We found that learning about both, effort and reward arises from the dopamine-rich midbrain and propagates to different cortical and striatal brain regions.
Hauser TU, Eldar E & Dolan RJ (2017). Separate mesocortical and mesolimbic pathways encode effort and reward learning signals. Proc Natl Acad Sci USA.
In a recent study published in eLife, we show that metacognition (the ability to consciously judge one’s performance) can be enhanced using a drug called propranolol. Propranolol blocks beta-adrenoceptors and thus impairs the effect of noradrenaline. Using a double-blind, placebo controlled drug study, we show that propranolol specifically enhances metacognition, but not perceptual decision making performance. A dopamine blockade (using amisulpride) did not affect either process.
Our paper also received some media coverage: The New Scientist just published a nice article about the study. Please note that the title of the article is misleading and was not approved by us. This study investigates the effect of drugs on metacognition and has nothing to do with OCD or OCD treatment.
Hauser TU*, Allen M*, Purg N, Moutoussis M, Rees G & Dolan R (2017). Noradrenaline blockade specifically enhances metacognitive performance. eLife 6: e24901
Can features of a psychiatric disorder actually have beneficial effects under certain conditions? This is the question that we asked in our new paper that just came out in PLOS Computational Biology. We were particularly interested in an indecisiveness that is often reported in patients with OCD.
Using an information gathering task, in which one is able to collect additional information before committing to a decision, we showed that juvenile OCD patients indeed won more points. Using computational modelling, we were then able to pin down the computational mechanism to a delayed emergence of a subjective feeling of urgency to respond. Our finding thus shows that under certain circumstance, an indecisiveness can actually have beneficial consequences.
Hauser TU, Moutoussis M, Iannaccone R, Brem S, Walitza S, Drechsler R*, Dayan P* & Dolan RJ* (2017). Increased decision thresholds enhance information gathering performance in juvenile obsessive-compulsive disorder (OCD). PLoS Comput Biol 13(4): e1005440
I am really proud to announce that I have just preprinted my first ever paper on BioRxiv. In this paper, we investigate the link between metacognition and compulsivity.
Metacognition is the ability – or insight – to monitor your performance. So if you have good metacognitive abilities, you can reliably judge how well you perform on a given task. If not, you have difficulty to say how well you did. Obviously this is critical for our decision making, because you have to know how good you do in your tasks.
Interestingly, it has been suggested that many people with mental health problems have difficulties with such metacognitive decisions. Here we examined how healthy people with higher compulsivity scores perform on such a task. We find that high compulsive participants have a lower metacognitive ability. This difficulty extends a perceptual decision making weakness in our task.
Our findings support an idea of lower metacognitive abilities in a compulsivity spectrum, and thus suggest that metacognitive intervention may help people with higher obsessive-compulsive traits.
The link to our paper is here: http://biorxiv.org/content/early/2017/01/05/098277
In our most recent paper, we investigate how brain stimulation (transcranial Direct Current Stimulation, tDCS) can alter neural activity, and how this is specific to a particular arithmetic operation. We used simultaneous tDCS-fMRI to probe the brain regions that are affected by tDCS. We find that activity in the inferior prefrontal cortex is altered during stimulation, but only so when subjects use arithmetic procedures (compared to fact retrieval). These findings are important because they adress two issues: first, it is largely unknown where tDCS really affects the brain – using simulations, we show that these models provide a useful approximation for where the effect really takes place. Second, we illustrate why there is not one single stimulation protocol that enhances all arithmetic/cognitive functions: the brain uses different networks for different functions. So it only works if we stimulate a network that is actually involved. This is also why we need stimulation protocols that are tailored to a specific function, rather than a general “cognition booster”.
Hauser TU, Rütsche B, Wurmitzer K, Brem S, Ruff CC, Grabner RH. (2016). Neurocognitive effects of transcranial Direct Current Stimulation in arithmetic learning and performance: A simultaneous tDCS-fMRI study. Brain Stim
I have been fortunate to coauthor two recent papers, both published in PNAS.
In the first one (Eldar et al., 2016), we investigated how humans develop avoidance habits and how their learning strategies are related to functional activation and gray matter structure in the striatum.
The second publication (Whitaker et al., 2016) is the first paper from our big NSPN study that investigates how the brain and cognitive functions mature over adolescence.
Eldar E, Hauser TU, Dayan P*, Dolan RJ*. (2016). Striatal structure and function predict individual biases in learning to avoid pain. Proc Natl Acad Sci USA 113(17):4812-4817
Whitaker KJ*, Vertes PE*, Romero-Garcia R, Vasa F, Moutoussis M, Prabhu G, Weiskopf N, Callaghan MF, Wagstyl K, Rittman T, Tait R, Ooi C, Suckling J, Inkster B, Fonagy P, Dolan RJ, Jones PE, Goodyer IM, NSPN Consortium, Bullmore ET. (2016). Adolescence is associated with genomically patterned consolidation of the hubs of the human brain connectome. Proc Natl Acad Sci USA
Our new paper in Trends in Neurosciences, we explain how computational psychiatry tries to understand the mechanisms in psychiatric disorders like attention deficit hyperactivity disorder (ADHD). We demonstrate how important it is to have an understanding of several levels of description (Marr’s levels of analysis), and to combine these levels to develop biologically driven, mechanistic new hypotheses about pathomechanisms. In this paper we further suggest that ADHD is mainly a disorder of aberrant neural gain modulation and we show how converging evidence on different levels of description support our notion.
Hauser TU, Fiore V, Moutoussis M & Dolan RJ (2016). Computational Psychiatry of ADHD: Neural Gain Impairments across Marrian Levels of Analysis. Trends Neurosci.
Our new paper in the Journal of Neuroscience suggest a new way of analyzing simultaneous EEG-fMRI data. Using this approach, one is able to obtain the timing of multiple fMRI-defined brain regions. We show this in two medial prefrontal areas (vmPFC, dmPFC) in the context of reward learning. In principle, this method is applicable to all simultaneous EEG-fMRI data.
We are thus thinking about implementing the protocol as an SPM toolbox. If you are interested in this, please let us know…
The slides from the UCL computational psychiatry course are now online. There, you can find all slides as well as the audio-files from all the speakers. The talks were all excellent and are worth listening to. My slides, etc, are – of course – also available there. You can find everything here: https://sites.google.com/site/comppsychcourse/2015schedule.
We also just published a new paper on arithmetic learning and tDCS in the European Journal of Neuroscience. More details are available in my post here: http://v1.tobiashauser.ch/papers/arithmetic-learning-modulated-by-tdcs/.
I will be talking at the UCL Computational Psychiatry Course 29th & 30th April at Queen Square London, together with Karl Friston, Peter Dayan, Michael Moutoussis, Rick Adams, and many other excellent speakers. The course will cover computational modelling, neurotransmitter systems, and also various psychiatric disorders.
I will be speaking about attention deficit/hyperactivity disorder (ADHD) and obsessive-compulsive disorder (OCD).
Have a look at the website of this great course: Computational Psychiatry Website
The organizers also plan to make the talks and slides downloadable on the website for those who cannot attend.