A review of machine learning in scanpath analysis for passive gaze-based interaction.

The scanpath is an important concept in eye tracking. It refers to a person's eye movements over a period of time, commonly represented as a series of alternating fixations and saccades. Machine learning has been increasingly used for the automatic interpretation of scanpaths over the past few years, particularly in research on passive gaze-based interaction, i.e., interfaces that implicitly observe and interpret human eye movements, with the goal of improving the interaction. This literature review investigates research on machine learning applications in scanpath analysis for passive gaze-based interaction between 2012 and 2022, starting from 2,425 publications and focussing on 77 publications. We provide insights on research domains and common learning tasks in passive gaze-based interaction and present common machine learning practices from data collection and preparation to model selection and evaluation. We discuss commonly followed practices and identify gaps and challenges, especially concerning emerging machine learning topics, to guide future research in the field.

Digital ink and differentiated subjective ratings for cognitive load measurement in middle childhood.

BACKGROUND: New methods are constantly being developed to adapt cognitive load measurement to different contexts. However, research on middle childhood students' cognitive load measurement is rare. Research indicates that the three cognitive load dimensions (intrinsic, extraneous, and germane) can be measured well in adults and teenagers using differentiated subjective rating instruments. Moreover, digital ink recorded by smartpens could serve as an indicator for cognitive load in adults. AIMS: With the present research, we aimed at investigating the relation between subjective cognitive load ratings, velocity and pressure measures recorded with a smartpen, and performance in standardized sketching tasks in middle childhood students. SAMPLE: Thirty-six children (age 7-12) participated at the university's laboratory. METHODS: The children performed two standardized sketching tasks, each in two versions. The induced intrinsic cognitive load or the extraneous cognitive load was varied between the versions. Digital ink was recorded while the children drew with a smartpen on real paper and after each task, they were asked to report their perceived intrinsic and extraneous cognitive load using a newly developed 5-item scale. RESULTS: Results indicated that cognitive load ratings as well as velocity and pressure measures were substantially related to the induced cognitive load and to performance in both sketching tasks. However, cognitive load ratings and smartpen measures were not substantially related. CONCLUSIONS: Both subjective rating and digital ink hold potential for cognitive load and performance measurement. However, it is questionable whether they measure the exact same constructs.

Investigating the Usability of a Head-Mounted Display Augmented Reality Device in Elementary School Children.

Augmenting reality via head-mounted displays (HMD-AR) is an emerging technology in education. The interactivity provided by HMD-AR devices is particularly promising for learning, but presents a challenge to human activity recognition, especially with children. Recent technological advances regarding speech and gesture recognition concerning Microsoft's HoloLens 2 may address this prevailing issue. In a within-subjects study with 47 elementary school children (2nd to 6th grade), we examined the usability of the HoloLens 2 using a standardized tutorial on multimodal interaction in AR. The overall system usability was rated "good". However, several behavioral metrics indicated that specific interaction modes differed in their efficiency. The results are of major importance for the development of learning applications in HMD-AR as they partially deviate from previous findings. In particular, the well-functioning recognition of children's voice commands that we observed represents a novelty. Furthermore, we found different interaction preferences in HMD-AR among the children. We also found the use of HMD-AR to have a positive effect on children's activity-related achievement emotions. Overall, our findings can serve as a basis for determining general requirements, possibilities, and limitations of the implementation of educational HMD-AR environments in elementary school classrooms.

Automatic Visual Attention Detection for Mobile Eye Tracking Using Pre-Trained Computer Vision Models and Human Gaze.

Processing visual stimuli in a scene is essential for the human brain to make situation-aware decisions. These stimuli, which are prevalent subjects of diagnostic eye tracking studies, are commonly encoded as rectangular areas of interest (AOIs) per frame. Because it is a tedious manual annotation task, the automatic detection and annotation of visual attention to AOIs can accelerate and objectify eye tracking research, in particular for mobile eye tracking with egocentric video feeds. In this work, we implement two methods to automatically detect visual attention to AOIs using pre-trained deep learning models for image classification and object detection. Furthermore, we develop an evaluation framework based on the VISUS dataset and well-known performance metrics from the field of activity recognition. We systematically evaluate our methods within this framework, discuss potentials and limitations, and propose ways to improve the performance of future automatic visual attention detection methods.

ARETT: Augmented Reality Eye Tracking Toolkit for Head Mounted Displays.

Currently an increasing number of head mounted displays (HMD) for virtual and augmented reality (VR/AR) are equipped with integrated eye trackers. Use cases of these integrated eye trackers include rendering optimization and gaze-based user interaction. In addition, visual attention in VR and AR is interesting for applied research based on eye tracking in cognitive or educational sciences for example. While some research toolkits for VR already exist, only a few target AR scenarios. In this work, we present an open-source eye tracking toolkit for reliable gaze data acquisition in AR based on Unity 3D and the Microsoft HoloLens 2, as well as an R package for seamless data analysis. Furthermore, we evaluate the spatial accuracy and precision of the integrated eye tracker for fixation targets with different distances and angles to the user (n=21). On average, we found that gaze estimates are reported with an angular accuracy of 0.83 degrees and a precision of 0.27 degrees while the user is resting, which is on par with state-of-the-art mobile eye trackers.

GABA suppresses neurogenesis in the adult hippocampus through GABAB receptors.

Adult neurogenesis is tightly regulated through the interaction of neural stem/progenitor cells (NSCs) with their niche. Neurotransmitters, including GABA activation of GABAA receptor ion channels, are important niche signals. We show that adult mouse hippocampal NSCs and their progeny express metabotropic GABAB receptors. Pharmacological inhibition of GABAB receptors stimulated NSC proliferation and genetic deletion of GABAB1 receptor subunits increased NSC proliferation and differentiation of neuroblasts in vivo. Cell-specific conditional deletion of GABAB receptors supports a cell-autonomous role in newly generated cells. Our data indicate that signaling through GABAB receptors is an inhibitor of adult neurogenesis.

[A standardised German translation of the STAndards for Reporting of Diagnostic accuracy studies (STARD statement)*: Methodological aspects]. / Eine standardisierte Übersetzung der STAndards for Reporting of Diagnostic accuracy studies (STARD Statement) in Deutsch: Methodische Aspekte.

BACKGROUND: In order to be comprehensible and comparable scientific data should be reported according to a certain standard. One example is the 'STAndards for Reporting of Diagnostic Accuracy (STARD) Statement', a 25-item checklist for the appropriate conduct and reporting of diagnostic studies. Usually such scientific standards are published in English. The International Society for Pharmacoeconomics and Outcome Research (ISPOR) has developed guidelines for the translation and cultural adaptation of written medical instruments. The aim was to apply these ISPOR criteria to the German translation of the STARD Statement in order to allow for authorisation to be conferred by the original authors. METHODS: In cooperation with the original authors the STARD statement was translated according to the ISPOR steps: (1) Preparation, (2) Forward Translation, (3) Reconciliation, (4) Back Translation, (5) Back Translation Review, (6) Harmonisation, (7) Cognitive Debriefing, which evaluated comprehensiveness and linguistic style with marks from 1 (very good) to 6 (insufficient), and (8) Review of Cognitive Debriefing Results and Finalisation. RESULTS: Die ISPOR criteria applied reasonably to the translation process, which required the work input and energy of four scientists and one professional translator and 177 accumulated working hours. The cognitive debriefing resulted in average grades 1.62±0.33 and 1.72±0.39 for comprehensiveness and linguistic style, respectively. Finally, the German STARD version was authorised by the original authors. CONCLUSION: Die ISPOR guidelines seem to be a suitable means to facilitate the structured adaptation of defined criteria for the reporting of studies, such as the STARD statement, to other languages.

Transition Metal Complexes with Organoazide Ligands: Synthesis, Structural Chemistry, and Reactivity.

A drastically enhanced stability is observed for organoazides (RN3 ) in the presence of Cu2+ or Pd2+ when the azido group is included in a ligand system chelating the transition metal ions. X-ray structure analysis of such complexes (the structure of a cyclohexaneazide palladium complex is depicted) confirms that the alkylated nitrogen atom of the N3 moiety is coordinated to the transition metal center.