How effortful is cognitive control? Insights from a novel method measuring single-trial evoked beta-adrenergic cardiac reactivity

The ability to adjust attentional focus to varying levels of task demands depends on the adaptive recruitment of cognitive control processes. The present study investigated for the first time whether the mobilization of cognitive control during response-conflict trials in a flanker task is associated with effort-related sympathetic activity as measured by changes in the RZinterval at a single-trial level, thus providing an alternative to the pre-ejection period (PEP) which can only be reliably measured in ensemble-averaged data. We predicted that response conflict leads to a physiological orienting response (i.e. heart rate slowing) and increases in effort as reflected by changes in myocardial beta-adrenergic activity (i.e. decreased RZ interval). Our results indeed showed that response conflict led to cardiac deceleration and decreased RZ interval. However, the temporal overlap of the observed heart rate and RZ interval changes suggests that the effect on the latter reflects a change in cardiac pre-load (Frank-Starling mechanism). Our study was thus unable to provide evidence for the expected link between cognitive control and cardiovascular effort. However, it demonstrated that our single-trial analysis enables the assessment of transient changes in cardiac sympathetic activity, thus providing a promising tool for future studies that aim to investigate effort at a single-trial level

Physiological synchrony is associated with attraction in a blind date setting

Action Contro

Depth Control for Blind Water Jet Drilling in Bone

Abstract - When surgically drilling blind holes in bone using a Water Jet (WJ), control over the resulting depth is a challenging issue of paramount concern. This thesis was part of a project aimed at replacing the awl and mallet technique used in traditional microfracture procedures with an arthroscopic high-pressure WJ instrument is capable of accurately drilling 2–4 mm deep holes in subchondral bone. The focus of this paper was to develop, analyze and evaluate concepts for ensuring the depthwise accuracy of a microfracturing WJ. Research was performed on both WJ systems and the microfracture procedure, and a thorough problem analysis detailing all concerning requirements and parameters was set up. It was determined that due to the strong non-uniformity of human bone, both spatially and between subjects, a WJ capable of monitoring the depth and implementing a closed-loop control system was needed to ensure safe and accurate drilling. To measure the depth of the hole and allow for feedback control, a flexible Nickel Titanium probe concept was devised and tested. The concept featured a 3D printed nozzle with built-in WJ orifice and depth probe, which could be extended down the hole made by the WJ by an ex-vivo actuator featurimg load and displacement sensors. When the load sensor detected a sudden rise in extension resistance, bottom contact was assumed and the hole depth was calculated based on the displacement of the probe. A proof-of-concept experiment showed the viability of using a flexible probe to measure the depth. Additionally, the algorithm produced for calculating the depth was shown to be robust against the hysteresis and backlash exhibited by the setup. When probing holes with depths of 0, 1, 2, 3, 4 and 5 mm and bore diameters of 1, 1.5, and 2 mm drilled in solid PMMA, the prototype managed an error mean of 0.00 mm with a SD of 0.19 mm. To test the probe in holes shaped as expected during microfracture surgery, a virtual interference experiment was carried out using mCT scans of WJ-drilled bones and simulated probes of varying diameters. Seven scans were probed from 4 different angles each; the results suggested that a probe with a 0.2–0.3 mm diameter was optimal in terms of traversing the hole without blockages and without risking over-penetration. Moreover, this thesis produced recommendations on carrying the project further, towards a fully integrated system capable of drilling accurate blind holes in human bone, in a closed-loop depth-controlled manner.BMEBioMechanical EngineeringMechanical, Maritime and Materials Engineerin

Prepocesssing pupil size data: Guidelines and code

Pupillometry has been one of the most widely used response systems in psychophysiology. Changes in pupil size can reflect diverse cognitive and emotional states, ranging from arousal, interest and effort to social decisions, but they are also widely used in clinical practice to assess patients’ brain functioning. As a result, research involving pupil size measurements has been reported in practically all psychology, psychiatry, and psychophysiological research journals, and now it has found its way into the primatology literature as well as into more practical applications, such as using pupil size as a measure of fatigue or a safety index during driving. The different systems used for recording pupil size are almost as variable as its applications, and all yield, as with many measurement techniques, a substantial amount of noise in addition to the real pupillometry data. Before analyzing pupil size, it is therefore of crucial importance first to detect this noise and deal with it appropriately, even prior to (if need be) resampling and baseline-correcting the data. In this article we first provide a short review of the literature on pupil size measurements, then we highlight the most important sources of noise and show how these can be detected. Finally, we provide step-by-step guidelines that will help those interested in pupil size to preprocess their data correctly. These guidelines are accompanied by an open source MATLAB script (available at https://github.com/ElioS-S/pupil-size). Given that pupil diameter is easily measured by standard eyetracking technologies and can provide fundamental insights into cognitive and emotional processes, it is hoped that this article will further motivate scholars from different disciplines to study pupil size.Action Contro

Physiological synchrony is associated with cooperative success in real-life interactions

Cooperation is pivotal for society to flourish. To foster cooperation, humans express and read intentions via explicit signals and subtle reflections of arousal visible in the face. Evidence is accumulating that humans synchronize these nonverbal expressions and the physiological mechanisms underlying them, potentially influencing cooperation. The current study is designed to verify this putative linkage between synchrony and cooperation. To that end, 152 participants played the Prisoner’s Dilemma game in a dyadic interaction setting, sometimes facing each other and sometimes not. Results showed that synchrony in both heart rate and skin conductance level emerged during face-to-face contact. However, only synchrony in skin conductance levels predicted cooperative success of dyads. Crucially, this positive linkage was strengthened when participants could see each other. These findings show the strong relationship between our bodily responses and social behavior, and emphasize the importance of studying social processes between rather than within individuals in real-life interactions.Action Contro