What does it mean to justify your statistical decisions?

Lakens and 87 other researches, including me, recently published a position paper on the p-level controversy. You can find the OSF-repo here: https://osf.io/by2kc/ Part of our argument is that instead of swallowing a specific alpha-threshold (e.g. 0.05 or 0.005) as gospel, every researcher is asked to justify her or his choices (ideally before data collection). What… Read more »

How does it feel to write a second PhD

Public and private Last week i had the viva for my Dr.rer.nat. To be specific, it was a sunny afternoon on a tuesday, the 28th of march 2017. We drew a small crowd. Not only did i defend in front of four professors. It was also a public event, and because my colleague and friend… Read more »

coding screens

Some Thoughts on Code Quality in Academia

I work in a neuroscience lab. Yet, during most day hours (and some night hours), I sit in front of a computer and write code. I guess you could group this code in three domains: Study Preparation This can be workspace definitions, protocols and scripts to run experiments, or low-level code to interface measurement devices…. Read more »

Neurofeedback Difficulty and Mental Effort

In sports training, a good way to set the intensity of a training session is according to your ability. If you train too hard, go softer. If you train too soft, go harder. This approach seems intuitive. Difficulty adaptation based on actual challenge seems sensible. But how can challenge be measured objectively? When is the… Read more »

Boundary element models of several brain areas

Put Shortly: If you want to perform source reconstruction for a region of interest, and therefore ignore some of the grid points of an evenly spaced source grid, these boundary-element models of several brain areas might be useful. In a previous post, i described how to construct a symetric headmodel based on the ICBM152 template… Read more »

Template Headmodel for Fieldtrip EEG Source Reconstruction based on ICBM152

Fieldtrip [1] includes a template headmodel based on the “Colin27” anatomical MRI. While this model is fine the way it is, there are some reasons why i do not like to use it. Colin27 is not symetric and also only based on a single individual. This can cause problems when you visualize your sources on… Read more »

Skin in the Game

There are a couple of tenured, influential professors who do not like data sharing and prefer rackets consentual collaboration. They write editorials in high-impact journals and call researchers who utilize open data „research parasites“. There are a couple of tenured, influential professors, who do like data sharing. They post blogs and rant on twitter and… Read more »

The first shadowrunner

As a teenager, i was hooked on cyberpunk. One of the core aspects of the cyberpunk genre is to live outside of government and corporate control as some kind of shadow-running outlaw, and using custom-made electronics and self-written software to jack into cyberspace, hack into secure systems and fight powerful AIs. Many, including me, consider… Read more »

Is the p-value a good measure for the weight of statistical evidence?

Many researchers naively follow the concept that a p-value below a certain threshold (traditionally .05)  is to be considered significant, and can therefore be considered as evidence that H1 is true, while a p-value above that level is considered not significant and therefore evidence that H0 is true. This Neyman-Pearson approach to statistical testing is… Read more »

Interpretation of statistical evidence and the naturalistic fallacy

Richard Royall starts his discussion about the interpretation of some data in regard to hypothesis A versus B as asking one of three questions: What does this observation tell me about A versus B? What do i believe, now that i have this observation? What should i do, now that i have this observation?1 He… Read more »

  • A couple of lectures i enjoyed

    There is nothing that compares to watching middle-aged men talking nerdy to an invisible audience and scribbling math on a chalkboard! I collected a list of free lectures which i enjoyed. The collection has a focus on STEM, and includes math, probability, information theory and electronics.  I will probably add lectures to the collection when… Read more »

  • Cheap probe for the magnetic field induced by your TMS

    I wanted to check the timing of a TMS-protocol using an external trigger, and sometimes i want to demonstrate the current induction in class. MagVenture sells the MagProbe, to be plugged into BNC or DIN. This would allow you to measure the magnetic field induced by the TMS. They also offer a 3-D version, and… Read more »

  • On being challenged adequately by a restorative BCI

    The utility of a restorative BCI depends not only on machine learning measures like classification accuracy, but also on how the subject experiences the intervention. Roughly a quarter of subjects appear to suffer from BCI-illiteracy, i.e. they have difficulty when trying to control a BCI. An interesting question is whether they differ in their experience… Read more »

  • The difficulty of restorative BCIs, considering Linear Discrimant Analysis

    Linear Discriminant Analysis (LDA) is characterized by means (µ1,µ2) for each class and the feature covariance matrix Σ, which is considered to be equal in both classes. Mean and covariance are usually estimated during a calibration session and transformed into feature weights ω and bias b, resulting in a discriminative function D(x). Given a feature… Read more »

  • On exploiting the cue from cue-paced, synchronous BCIs

    Many BCIs are cue-paced, i.e. they signal the start and end of the control phase to the user. Because this gives the BCI a task-like structure, such a synchronous approach is not very useful for assistive applications. Yet, there are several benefits of such a task-structure, which makes this approach very applicable for restorative BCIs… Read more »

  • Connecting BVR, Magventure and Localite – Solder the Circuit

    In two earlier posts, i described the general idea on how to connect Brain Vision Recorder, a Magventure TMS and Localite Software, and how to make the box. In this post, i will follow up, and describe how to design, solder and test the circuit. What you need: What you will need is the box… Read more »

  • Connecting BVR, Magventure and Localite – Make the Box

    In an earlier post, i described how to connect Brain Vision Recorder, a Magventure TMS and Localite Software. In a later post, i describe how to solder the circuit. This would allow more flexible recordings  according to your uniqe needs, e.g. multi-channel MEP mapping. As i am currently constructing another box for our second TMS-device,… Read more »

  • Anodal stimulation over M1 might actually have effects on alpha power

    Horvath and colleagues published recently two large meta-analysis of effects of tDCS on cognitive measures and neurophysiological measures [1,2]. Essentially, they claim that tDCS has no reliable effects besides MEP modulation. And the effect size of this modulation appears to be decreasing since the first studies on tDCS fifteen years ago. This sounds like very… Read more »

  • Connecting BVR, Magventure and Localite – Discussing the Idea

    Recently, our lab purchased two MagVenture TMS devices together with the Localite setup for navigation. Both companies are independent, but collaborating strongly. Magventure offers the stimulator, Localite the hardware and software for navigation. The Magventure GUI is very easy to handle and i like how the Localite software allows to use template MRIs. It gives… Read more »

  • Neurosensory Effects of Transcranial Alternating Current Stimulation

    Probably everyone using transcranial current stimulation has made the experience that stimulation can cause neurosensory effects. This makes blinding the stimulation difficult, or even impossible. Usually, flickering phosphenes and skin sensations are perceived, but we also had subjects reporting feelings of dizziness and pressure. There is evidence that sensations elicited by tDCS fade with stimulation… Read more »