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Postdoctoral position in body representations and multisensory integration – University of Delaware

A postdoctoral research position is now available in our lab. The postdoctoral researcher will take a lead role in designing and implementing cognitive neuroscience studies using the following techniques: functional neuroimaging, transcranial magnetic stimulation, research with brain-damaged individuals, and psychophysical/behavioral methods. Research topics include multisensory integration, action, touch, proprioception, plasticity, and body representations.

Our newly constructed Center for Biomedical and Brain Imaging houses a Siemens Prisma 3T MRI suite, TMS, EEG, fNIRS, eye trackers, and equipment for tactile and multisensory testing.  We also have access to a large database of brain-damaged individuals who are active in research. Furthermore, the University of Delaware is located on the Northeast Corridor, within two hours of New York City, Philadelphia, Baltimore, and Washington, DC.

This position is fully funded by a multi-institutional grant from the National Science Foundation awarded to Dr. Jared Medina. The initial appointment is for one year, with potential for two additional years based on progress. The position is available now.

Applicants should have a Ph.D. in cognitive neuroscience or a related field. Applicants with expertise in fMRI, TMS, or cognitive neuropsychology are encouraged to apply. We also encourage individuals with a background in studying tactile perception, multisensory processing, plasticity, and/or body representations to apply as well. Review of applications will begin on Monday, February 12, and will continue until filled.

We strongly encourage potential applicants to contact Jared Medina (jmedina@psych.udel.edu) before applying. Candidates should submit a CV, research statement, and the names of three references through the University of Delaware Jobs website (click “Staff”, job #105227).

No evidential value in samples of cognitive tDCS studies

Our new paper in Cortex with Sam Cason, “No Evidential Value in Samples of tDCS Studies of Cognition and Working Memory in Healthy Populations“, uses a p-curve analysis to examine the strength of evidence in the tDCS literature. Briefly, a p-curve analysis is used to examine the distribution of significant p-values (p < .05) in a literature.  If there is a real effect in the literature, the p-value distribution should be right-skewed, such that there are more p-values ranging from .00 to .01 compared to a bin ranging from .04 to .05.  Interestingly, if there is no real underlying effect, the p-curve should be flat (i.e. an equal distribution of p-values in these bins).  Furthermore, if someone is engaging in “questionable research practices”, this distribution may be left-skewed (more p-values from .04 to .05 vs. .00 to .01).

We used the p-curve analysis for two sets of studies in the tDCS literature.  One was a random selection of tDCS studies on cognition, and the second was a set of tDCS studies on working memory taken from a recent meta-analysis.  The p-value distribution from our sample of cognitive studies was not right-skewed, and our best estimate is that 8-16% of the studies from this sample would replicate.  For the sample of working memory papers, our estimate is that 5% of the studies would replicate.  We note that, given an α of .05, this is the same number of studies that would be expected to replicate if the data were randomly generated.

In the discussion, we note that these results do not mean that tDCS does not, or can not, influence cognitive processes. However, we are concerned that current practices in the general psychological literature (including small sample sizes, hypothesizing after the results are known, and multiple data analyses (the “garden of forking paths“) may lead to a literature with a low signal-to-noise ratio. Therefore, we strongly support preregistration of future tDCS studies, and replication of past tDCS studies, to better understand the relationship between brain stimulation and cognitive processing.

New papers!

We’ve had several papers published from the lab over the last few months – what follows is a quick review.

First, we published a paper co-authored with former graduate student Catie Duckett in the Journal of Experimental Psychology: Human Perception & Performance titled “Domain-general biases in spatial localization: Evidence against a distorted body model hypothesis“.  In it, we use evidence from a number of experiments to challenge the current hypothesis that our representation of the size and shape of our body is distorted.  Instead, we demonstrate that these distortion effects are more likely due to domain-general biases in spatial memory.

Second, I contributed to a Scholarpedia entry on perceived location of touch with Jack Brooks, a graduate student at the University of New South Wales.

Finally, Simon Fischer-Baum (Rice University) and I wrote a paper for an upcoming Special Issue of Cognitive Neuropsychology on “Theoretical and Methodological Issues for Twenty-First Century Cognitive Neuropsychology.”  In our article, “Single case cognitive neuropsychology in the age of big data“, we discuss reasons for the perceived decline in cognitive neuropsychological research in the last twenty years, some perils in “big data” approaches that are being proposed for understanding cognitive processes, and then note how combining neural data and behavioral data from single case studies in brain-damaged individuals can further develop theories of mind and brain.

New research on the mirror box illusion

Our paper with Yuqi Liu (graduate student) is out in Scientific Reports.  In it, we report a new version of the mirror box illusion.  In it, participants place their hands in opposing postures (i.e. one hand palm down, the other hand palm up) in the mirror box and synchronously (or asynchronously) opened/closed their hands.  In this condition, participants may see the reflection of their hand as palm up, while their actual hand (behind the mirror) is positioned palm down.

Interestingly, we found that for synchronous movements (when both hands opened/closed at the same time), participants reported feeling that the hand behind the mirror rotated, or “flipped” to match the position of their viewed hand.  Importantly, the hand behind the mirror didn’t move – the perceived sensation was illusory.

We then examined whether biomechanical constraints of the “body schema” (i.e. how can the arm realistically rotate) influenced the strength of the illusion.  For example, place your hands as in Figure d. below.  Rotating your left hand to match the position of the right hand is relatively easy.  Now do the same movement using the starting position in Figure e.  Note how the movement is more constrained at the end – this is due to biomechanical constraints that limit our movement.  We found that participants showed a stronger illusion for less constrained movements vs. more constrained movements – a surprising result given that there was no actual movement involved in the task.

In this illusion, we propose that its effectiveness is dictated, not only by well-known principles of multisensory integration, but also by knowledge about the configuration of our bodies.  This illusion is quite easy to do, and we suggest trying it at home – it’s quite compelling.

If you want to learn more about the mirror box illusion, see the video below and the related article in UDaily.

Summer Undergraduate Workshop in Cognitive and Brain Sciences

Thanks to generous funding from the National Science Foundation, we held our first Summer Undergraduate Workshop in Cognitive and Brain Sciences at the University of Delaware. We had a diverse, talented group of twenty undergraduates from around the nation here to learn about topics including vision, infant cognition, social neuroscience, language, replicability, neuropsychology, and more.  More information about the workshop can be found here, and we are looking forward to holding our next undergraduate workshop in Summer 2018.

Fall conference tour

The lab has just returned from the Society for Neuroscience annual meeting in San Diego, where we presented a poster on changes in tactile processing after numbing the lips – part of a collaboration with Elisabetta Ambron and H. Branch Coslett at the University of Pennsylvania.

After that, it was straight to Boston for the annual meeting of the Psychonomic Society.  Both Yuqi and I gave talks at the Tactile Research Group satellite meeting.  Her talk was on frames of reference in multisensory integration, while mine was on error patterns in tactile localization after stroke.  Then, Yuqi had a talk on multisensory integration and the mirror box illusion.  Feel free to e-mail me if you want to learn more about these projects.