A new paper led by Marinho Lopes is published on Clinical Neurophysiology. The study applied the brain network ictogenicity framework to quantify the inherent propensity to generate seizures from resting-state MEG recordings. We found that resting-state MEG functional networks from people with epilepsy are characterized by a higher propensity to generate seizures than those from healthy volunteers, with a classification accuracy of 73%. This sensitive computational modelling approach could in future aid diagnosis.
We carry on our research while everyone has adapted to work from home. Dominik has passed his PhD viva, a big achievement in a challenging year. Big congratulations Dr Krzeminski! Luke has started his new job at the University of Birmingham while maintains our close collaborations on several ongoing projects. We really appreciate their important contributions in the last few years and wish them all the best in their future careers.
A new paper led by Wojciech Zajkowski and Dominik Krezeminski is published on Computational Brain & Behavior. This study examined the neurocognitive processes underlying such voluntary decisions by integrating cognitive modelling of behavioral responses and EEG recordings in a probabilistic reward task. Human participants performed binary choices between pairs of unambiguous cues associated with identical reward probabilities at different levels. Higher reward probability accelerated RT, and participants chose one cue faster and more frequent over the other at each probability level. The behavioral effects on RT persisted in simple reactions to single cues. By using hierarchical Bayesian parameter estimation for an accumulator model, we showed that the probability and preference effects were independently associated with changes in the speed of evidence accumulation, but not with visual encoding or motor execution latencies. Time-resolved MVPA of EEG-evoked responses identified significant representations of reward certainty and preference as early as 120 ms after stimulus onset, with spatial relevance patterns maximal in middle central and parietal electrodes. Furthermore, EEG-informed computational modelling showed that the rate of change between N100 and P300 event-related potentials modulated accumulation rates on a trial-by-trial basis. Our findings suggest that reward probability and spontaneous preference collectively shape voluntary decisions between equal options, providing a mechanism to prevent indecision or random behavior.
The COVID‐19 pandemic has impacted almost every aspect of our lives, including the way how we conduct research. This article shares our experience of running behavioural experiments online, with some hints on how to make this process smoother.
There are commercial products available for online testing (Testable, Inquisit, or Gorilla). However, if you opt for open-source solutions, there is no single tool to solve the whole problem. Thus, right after you come up with a design of an experiment you need to make a few choices:
1. Programming toolkit for your experiment
Lab.js - probably the easiest to use for people not too experienced with web development. It has a nice web interface but still requires some programming.
PsychoJS – recommended for those already familiar with psychopy, as PsychoPy Builder can automatically convert an exising experiment into JS, albeit with limited functionalities.
jsPsych – our current choice, as it is easier to use if you need to design an experiment from scratch. Its website provides some good tutorials with many predefined plugins to use, eg. random dot motion (RDK) task. Also, the community is quite active on the discussion forum.
2. Hosting platform for the experiment
You can host the experiment wherever you want: on your university server, github pages, some other hosting provider, but our choice is Pavlovia as it provides nice ecosystem for the experiment code hosting and data saving that relies on git. After you share your experiment publicly, Pavlovia helps you saving the data on the server, such that you can download it with just one command line: git pull.
Pavlovia requires a paid license or buying storage credits.
3. Recruitment platform
Finally, it comes the time to recruit your participants. For pilots, you may recruit from local participant panels in a normal way (e.g., SONA as used in many UK universities). One advantage of online experiments is that you can use existing services to reach a large participant portal. We evalauted two solutions: Amazon Mechanical Turk and Prolific. We eventually decided to use Prolific because of their easy-to-use prescreening procedure.
From Prolific you will get a unique code at the end of the experiment, which indicates that your participants successfully finished the task. It can look like this in jsPsych (at the end of your experiment):
With all this you are basically ready to go! But there are some important details you need to be careful with.