Scanpath Length Research Articles

Integrating Biomarkers From Virtual Reality and Magnetic Resonance Imaging for the Early Detection of Mild Cognitive Impairment Using a Multimodal Learning Approach: Validation Study.

Early detection of mild cognitive impairment (MCI), a transitional stage between normal aging and Alzheimer disease, is crucial for preventing the progression of dementia. Virtual reality (VR) biomarkers have proven to be effective in capturing behaviors associated with subtle deficits in instrumental activities of daily living, such as challenges in using a food-ordering kiosk, for early detection of MCI. On the other hand, magnetic resonance imaging (MRI) biomarkers have demonstrated their efficacy in quantifying observable structural brain changes that can aid in early MCI detection. Nevertheless, the relationship between VR-derived and MRI biomarkers remains an open question. In this context, we explored the integration of VR-derived and MRI biomarkers to enhance early MCI detection through a multimodal learning approach. We aimed to evaluate and compare the efficacy of VR-derived and MRI biomarkers in the classification of MCI while also examining the strengths and weaknesses of each approach. Furthermore, we focused on improving early MCI detection by leveraging multimodal learning to integrate VR-derived and MRI biomarkers. The study encompassed a total of 54 participants, comprising 22 (41%) healthy controls and 32 (59%) patients with MCI. Participants completed a virtual kiosk test to collect 4 VR-derived biomarkers (hand movement speed, scanpath length, time to completion, and the number of errors), and T1-weighted MRI scans were performed to collect 22 MRI biomarkers from both hemispheres. Analyses of covariance were used to compare these biomarkers between healthy controls and patients with MCI, with age considered as a covariate. Subsequently, the biomarkers that exhibited significant differences between the 2 groups were used to train and validate a multimodal learning model aimed at early screening for patients with MCI among healthy controls. The support vector machine (SVM) using only VR-derived biomarkers achieved a sensitivity of 87.5% and specificity of 90%, whereas the MRI biomarkers showed a sensitivity of 90.9% and specificity of 71.4%. Moreover, a correlation analysis revealed a significant association between MRI-observed brain atrophy and impaired performance in instrumental activities of daily living in the VR environment. Notably, the integration of both VR-derived and MRI biomarkers into a multimodal SVM model yielded superior results compared to unimodal SVM models, achieving higher accuracy (94.4%), sensitivity (100%), specificity (90.9%), precision (87.5%), and F1-score (93.3%). The results indicate that VR-derived biomarkers, characterized by their high specificity, can be valuable as a robust, early screening tool for MCI in a broader older adult population. On the other hand, MRI biomarkers, known for their high sensitivity, excel at confirming the presence of MCI. Moreover, the multimodal learning approach introduced in our study provides valuable insights into the improvement of early MCI detection by integrating a diverse set of biomarkers.

Effect of a calibration aid and the intraoral scanner on the registration of a partially edentulous maxilla: An in vitro study

Precise data are a prerequisite for accurately fitting restorations. Therefore, intraoral scanners have to be reliable. Data on differences between the same model of intraoral scanning systems are lacking. This in vitro study evaluated differences in the scanning accuracy of a partially edentulous maxilla between combinations of new intraoral scanners of a single model from the same manufacturer (Primescan; Dentsply Sirona) and several calibration aids. The in vitro reference model simulated a maxilla with 6 prepared teeth for a complete arch fixed partial denture. Five precision ceramic balls were used to detect dimensional deviation between the reference model and the scan. Distances were divided into 4 categories, from short distances between 2 neighboring precision balls to the cross-arch distance with the scan path comprising all 5 balls. For each combination of 4 new intraoral scanners and their respective calibration aids, 12 model registrations were generated. The data were statistically analyzed using ANOVA (α=.05). Distance deviations increased with increasing scan path length and were significantly affected by the covariates "scanner" (P≤.023) and, for 3 of 4 distance categories, the "calibration aid" (short, medium, and long distances: P≤.013). For short and medium distances, acceptable scanning results were achieved for all test groups. The largest deviation was 539µm for the cross-arch distance. Scanning accuracy depends on the scanner and the calibration aid used, in particular, for spans exceeding a single quadrant.

Visual salience is affected in participants with schizophrenia during free-viewing

Abnormalities in visual exploration affect the daily lives of patients with schizophrenia. For example, scanpath length during free-viewing is shorter in schizophrenia. However, its origin and its relevance to symptoms are unknown. Here we investigate the possibility that abnormalities in eye movements result from abnormalities in visual or visuo-cognitive processing. More specifically, we examined whether such abnormalities reflect visual salience in schizophrenia. Eye movements of 82 patients and 252 healthy individuals viewing natural and/or complex images were examined using saliency maps for static images to determine the contributions of low-level visual features to salience-guided eye movements. The results showed that the mean value for orientation salience at the gazes of the participants with schizophrenia were higher than that of the healthy control subjects. Further analyses revealed that orientation salience defined by the L + M channel of the DKL color space is specifically affected in schizophrenia, suggesting abnormalities in the magnocellular visual pathway. By looking into the computational stages of the visual salience, we found that the difference between schizophrenia and healthy control emerges at the earlier stage, suggesting functional decline in early visual processing. These results suggest that visual salience is affected in schizophrenia, thereby expanding the concept of the aberrant salience hypothesis of psychosis to the visual domain.

Characteristics of visual perception of patients’ faces and the formation of “observation” in the process of training cosmetologists

Professional experience assists specialists in processing information more quickly and effectively making precise decisions. Visual expertise, as a crucial component of experience, refers to the capability to rapidly perceive visual information within a specific professional domain, acquired through systematic education, professional development, and practice. Numerous studies utilize eye-tracking methods to analyze the relationship between professional experience and gaze patterns. For instance, experienced dermatologists have developed optimal scanning patterns, allowing them to efficiently allocate attention and accurately identify key diagnostic features within images amidst numerous secondary details. The purpose of this study is to analyze changes in oculomotor patterns after completing the author’s training program for doctors, aimed at versatile aesthetic analytics of the face, building individual treatment protocols and increasing the patient’s adherence to aesthetic medicine in order to assess the possibility of developing observation in the conditions of short-term training. Thirty cosmetic doctors participated in the study, which utilized eye-tracking methods with the Neuroburo program-hardware complex. The study was conducted in two phases – before and after training – with 15 patient facial images exhibiting various dermatological issues presented on a computer screen to the cosmetic doctors. Participants were tasked with identifying signs of dermatological disorders of the patients. Following training, a decrease in the number of fixations, an increase in saccadic amplitude, and a reduction in the overall scanning path length were observed among the cosmetic doctors. These findings indicate a more optimized perception strategy and suggest a more systematic and directed approach to diagnostic image analysis. The results suggest an enhanced global perception ability among the doctors, which may aid in recognizing broader patterns and structures and understanding the wider context and relationships between details.

The Impact of Reading Modalities and Text Types on Reading in School-Age Children: An Eye-Tracking Study

This study examined the eye movement patterns of 317 elementary students across reading conditions (audio-assisted reading (AR) and reading-only (R)) and text types (fiction and non-fiction) and identified eye movement parameters that predict their literal comprehension (LC) and inferential comprehension (IC). Participants, randomly assigned to either reading condition and either text type, answered questions assessing their LC and IC. Average fixation duration (AFD), total fixation duration (TFD), and scanpath length were used as eye movement parameters. The main effects of age were observed on all parameters, along with interaction effects between age and reading condition on TFD and scanpath length. These results indicate that children employ different reading strategies, depending on reading modalities and text types. When controlling for age, TFD had a positive impact on the LC of both text types in the AR, while in the R, it had a negative effect on the IC of both text types. Longer scanpaths predicted the IC of fiction in the AR; the LC and IC of non-fiction under the AR; and the LC of non-fiction within the R. AFD had a negative influence on the IC of fiction in the AR, as well as on the LC and IC of non-fiction in the AR, and the LC of non-fiction under the R. These findings highlight the importance of selecting appropriate reading strategies, based on reading modality and text type, to enhance reading comprehension. This study offers guidance for educators when providing reading instruction to school-age children.

Investigation of scan path optimization in improving proton pencil beam scanning continuous delivery

Objective. To investigate the impact of scan path optimization on the dose accuracy and beam delivery time (BDT) of proton pencil beam scanning in the dose-driven continuous scanning (DDCS). Approach. A diverse set of six clinical plans, representing various spot patterns and treatment sites, was used to evaluate the effectiveness of scan time optimization and scan length optimization. The DDCS dose discrepancy and BDT with optimized scan paths was compared to the default serpentine scan path. Main results. Both scan time optimization and scan path optimization were able to reduce the DDCS dose discrepancy compared to the default serpentine scan path. All plans, except for the layer repainting lung plan, achieved a 2%/2 mm gamma pass rate of over 99% and less than 1% PTV DVH root mean square error (RMSE) through scan path optimization. In the case of the layer repainting lung plan, when compared to the default serpentine scan path, the 2%/2 mm gamma pass rate showed improvements from 91.3% to 93.1% and 95.8%, while the PTV DVH RMSE decreased from 2.1% to 1.7% and 1.1% for scan time optimization and scan length optimization, respectively. Although scan time optimization resulted in shorter total scan times for all plans compared to the default scan path and scan length optimization tended to have longer total scan times. However, due to the short total scan times and their minimal contribution to the total BDT, the impact of scan path optimization on the total BDT was practically negligible. Significance. Both scan time optimization and scan length optimization proved to be effective in minimizing DDCS dose discrepancy. No definitive winner can be determined between these two optimization approaches. Both scan time and scan length optimization had minimal effect on the total BDT.

An updating-based working memory load alters the dynamics of eye movements but not their spatial extent during free viewing of natural scenes

The relationship between spatial deployments of attention and working memory load is an important topic of study, with clear implications for real-world tasks such as driving. Previous research has generally shown that attentional breadth broadens under higher load, while exploratory eye-movement behaviour also appears to change with increasing load. However, relatively little research has compared the effects of working memory load on different kinds of spatial deployment, especially in conditions that require updating of the contents of working memory rather than simple retrieval. The present study undertook such a comparison by measuring participants’ attentional breadth (via an undirected Navon task) and their exploratory eye-movement behaviour (a free-viewing recall task) under low and high updating working memory loads. While spatial aspects of task performance (attentional breadth, and peripheral extent of image exploration in the free-viewing task) were unaffected by the load manipulation, the exploratory dynamics of the free-viewing task (including fixation durations and scan-path lengths) changed under increasing load. These findings suggest that temporal dynamics, rather than the spatial extent of exploration, are the primary mechanism affected by working memory load during the spatial deployment of attention. Further, individual differences in exploratory behaviour were observed on the free-viewing task: all metrics were highly correlated across working memory load blocks. These findings suggest a need for further investigation of individual differences in eye-movement behaviour; potential factors associated with these individual differences, including working memory capacity and persistence versus flexibility orientations, are discussed.

Using Eye Tracking to Measure Overall Usability of Online Grocery Shopping Websites

This article examines usability evaluation methodologies, then presents a non-conscious behavioral indicator based on user eye movements and pupil dilation. The authors test how gender and online buying history affect the behavioral index's usability scores. This study uses three Iranian online food retailers. Thirty participants were asked to add things from predetermined grocery stores to virtual shopping carts before the experiment took them to the other two websites in a random order to collect eye movement data. Each group's presentation order was randomized. The number of fixations, number of saccades, total duration of fixations, scan-path length, pupil size, and task time were inversely linked with self-report usability measures. This research evaluates groups with different levels of online shopping expertise and gender based on experienced usability. Differences between groups suggest that user demographics affect usability.

Central Visual Attention in Primary Open-angle Glaucoma

SIGNIFICANCE To better understand the implication of a potential cognitive change in glaucoma, patients were stimulated in central visual areas considered functionally normal to discard an effect due to the loss of vision during an attentional task. The outcome might improve the follow-up on the impact of the pathology. PURPOSE This study aimed to evaluate the effect of primary open-angle glaucoma on the visual attention system by recording responses of behavioral and oculomotor strategies. METHODS We included 20 individuals with primary open-angle glaucoma (62.1 ± 7.2 years old), 18 age-matched control subjects (58.4 ± 7.2 years old), and 20 young control subjects (25.7 ± 3.5 years old). The procedure consisted of visual (eye-tracking recordings) and manual detection of a target. All participants had to detect a square with a vertical bar within distractors (squares, triangles, and circles with a horizontal or vertical bar) of identical size of 1.6 × 1.6° visual angle. The shapes were displayed concentrically on a radius of 5° of visual angle. All participants were tested to ensure that their visual field sensitivity was normal within ±5° central vision. RESULTS In responding manually, glaucoma participants were slower than age-matched control subjects (1723 ± 488 vs. 1263 ± 385 milliseconds; P < .01). Eye-tracking recordings showed that glaucoma participants found the target within the same time frame as age-matched control subjects. Compared with the young group, the scanpath length and average fixation duration on distractors were significantly longer for the glaucoma patients (+235 pixels, +104 milliseconds) and the age-matched control participants (+120 pixels, +39 milliseconds). Impaired contrast sensitivity was correlated with longer response time, longer scanpath, and longer fixation on distractors. CONCLUSIONS Glaucoma affects the manual response times in a visual attention task, but patients can visually detect the target as quickly as age-matched control subjects. Different clinical factors predicted the performances. The age of the patients was associated with longer scanpath. The visual field loss (mean deviation) was linked with longer visual response time. The loss of contrast sensitivity predicted the behavioral change on fixation duration to the distractors, global response time, visual response time, and scanpath length.

The effect of ketamine on eye movement characteristics during free-viewing of natural images in common marmosets.

Various eye movement abnormalities and impairments in visual information processing have been reported in patients with schizophrenia. Therefore, dysfunction of saccadic eye movements is a potential biological marker for schizophrenia. In the present study, we used a pharmacological model of schizophrenia symptoms in marmosets and compared the eye movement characteristics of marmosets during free-viewing, using an image set identical to those used for human studies. It contains natural and complex images that were randomly presented for 8 s. As a pharmacological model of schizophrenia symptoms, a subanesthetic dose of ketamine was injected intramuscularly for transient and reversible manipulation. Eye movements were recorded and compared under a ketamine condition and a saline condition as a control. The results showed that ketamine affected eye movement characteristics during free-viewing. Saccades amplitude and scanpath length were significantly reduced in the ketamine condition. In addition, the duration of saccades was longer under the ketamine condition than under the saline condition. A similar tendency was observed for the duration of fixations. The number of saccades and fixations tended to decrease in the ketamine condition. The peak saccades velocity also decreased after ketamine injection whereas there was no difference in the main sequence relationship between saccades amplitude and peak velocity. These results suggest that ketamine affected visual exploration but did not affect the oculomotor aspect of saccades in marmosets, consistent with studies in patients with schizophrenia. Therefore, we conclude that the subanesthetic dose of ketamine is a promising pharmacological model of schizophrenia symptoms in common marmosets and can be used in combination with free-viewing paradigms to establish “translatable markers” for schizophrenia in primates.

Technostress causes cognitive overload in high-stress people: Eye tracking analysis in a virtual kiosk test

In the midst of the COVID-19 pandemic, the use of non-face-to-face information and communication technology (ICT) such as kiosks has increased. While kiosks are useful overall, those who do not adapt well to these technologies experience technostress. The two most serious technostressors are inclusion and overload issues, which indicate a sense of inferiority due to a perceived inability to use ICT well and a sense of being overwhelmed by too much information, respectively. This study investigated the different effects of hybrid technostress—induced by both inclusion and overload issues—on the cognitive load among low-stress and high-stress people when using kiosks to complete daily life tasks. We developed a ‘virtual kiosk test’ to evaluate participants’ cognitive load with eye tracking features and performance features when ordering burgers, sides, and drinks using the kiosk. Twelve low-stress participants and 13 high-stress participants performed the virtual kiosk test. As a result, regarding eye tracking features, high-stress participants generated a larger number of blinks, a longer scanpath length, a more distracted heatmap, and a more complex gaze plot than low-stress participants. Regarding performance features, high-stress participants took significantly longer to order and made more errors than low-stress participants. A support-vector machine (SVM) using both eye tracking features (i.e., number of blinks, scanpath length) and a performance feature (i.e., time to completion) best differentiated between low-stress and high-stress participants (89% accuracy, 100% sensitivity, 83.3% specificity, 75% precision, 85.7% F1 score). Overall, under technostress, high-stress participants experienced cognitive overload and consequently decreased performance; whereas, low-stress participants felt moderate arousal and improved performance. These varying effects of technostress can be interpreted through the Yerkes-Dodson law. Based on our findings, we proposed an adaptive interface, multimodal interaction, and virtual reality training as three implications for technostress relief in non-face-to-face ICT.

Image analysis and error detection in source software code

Subject of study. We study cognitive mechanisms for the analysis of images of source software code and detection of errors in it by a human. Aim. The aim of this study is to determine the influence of the professional skill of visual error detection in a Python source code on the control over oculomotor processes to be used for the subsequent modeling of the identified principles in artificial intelligence systems. Method. The eye movement properties of a human during error detection in the images of software code were investigated using eye movement tracking technology by means of the Russian software–hardware suite “Neurobureau,” which enabled a complete set of psychophysiological studies to be conducted. The test subjects completed two tasks: explaining the software code and finding an error in it. Each task comprised 10 stimuli with software code in Python language normalized to length and complexity and with syntax highlighting. The task completion time was not limited. Eight programmers with different professional experience (from 1 to 13 years) participated in the study. Main results. With increasing professional skill in image analysis, humans develop eye movement strategies enabling more effective performance of tasks with minimum effort. These strategies entail division of an integral software code into individual units relevant for the analysis. We discovered that experienced programmers exhibited fewer fixations, shorter scanpath length, and larger saccade amplitudes than novice programmers. Notably, the speed of saccades, in particular the broad searching eye movements during the task of software code explanation, increases with professional experience. We demonstrated that visual error detection is mainly determined by recognition of the details in a text that can be found exclusively based on the semantics and grammar of the programming language. We established that reading of software code texts is different from both viewing visual scenes and reading texts written in a natural language. Professional experience minimizes the efforts in this work, similar to any other type of professional activity. Eye movement control during code reading is guided by the knowledge of the programming language, understanding of context, and knowledge of the semantics and grammar of the language, as well as the low-spatial-frequency description of the images of strings and words, which is used to develop the skill of reading and recognition of the general configuration of strings and words in a natural language. Practical significance. The conclusions obtained in this study can be used to describe the existing techniques and create new neuromorphic algorithms (based on the strategies developed during human evolution) for the generation and correction of software code.

The impact of COVID-19 pandemic on individuals at clinical high-risk for psychosis: Evidence from eye-tracking measures

Emerging evidence suggested that people with severe mental disorders were more vulnerable to the negative effects of the COVID-19 pandemic. However, few researches investigated the influence of global pandemics on people at clinical high risk (CHR) for psychosis. This study aimed to investigate the impact of the COVID-19 pandemic on clinical symptoms, psychological distress, and eye-tracking characteristics in CHR individuals and healthy participants. Forty-nine CHR individuals and 50 healthy controls (HC) were assessed by PTSD Checklist for DSM-5 (PCL-5), Perceived Stress Scale, 10-item version (PSS-10), and Coronavirus Impact Scale (CIS). Eye movement performances were measured by the tests of fixation stability, free-viewing, and anti-saccade. According to the mean score of CIS, participants were stratified into high-impact (n = 35) and low-impact (n = 64) subgroups. Compared with the HC group, CHR participants reported significantly higher levels of post-traumatic symptoms caused by the COVID-19 pandemic and showed abnormalities in most of the eye movement indexes. Among the altered indexes, the saccade amplitude of fixation stability test (far distractor), the scan path length of free-viewing test, and the accuracy of anti-saccade test were negatively affected by the severity of impact level in the CHR group. Moreover, the altered eye movement indexes were significantly associated with the total scores of CIS, PCL-5, and subscales of the Scale of Prodromal Syndromes (SOPS) among CHR individuals. Overall, our findings suggested the negative impact of the COVID-19 pandemic on the eye movement characteristics of CHR individuals. The present study provides valuable information on physiological distress related to the COVID-19 pandemic and sensitive neuropsychological biomarkers that interacted with social and environment stress in the CHR population.

Effective differentiation between depressed patients and controls using discriminative eye movement features

BackgroundDepression is a common debilitating mental disorder caused by various factors. Identifying and diagnosing depression are challenging because the clinical evaluation of depression is mainly subjective, lacking objective and quantitative indicators. The present study investigated the value and significance of eye movement measurements in distinguishing depressed patients from controls. MethodsNinety-five depressed patients and sixty-nine healthy controls performed three eye movement tests, including fixation stability, free-viewing, and anti-saccade tests, and eleven eye movement indexes were obtained from these tests. The independent t-test was adopted for group comparisons, and multiple logistic regression analysis was employed to identify diagnostic biomarkers. Support vector machine (SVM), quadratic discriminant analysis (QDA), and Bayesian (BYS) algorithms were applied to build the classification models. ResultsDepressed patients exhibited eye movement anomalies, characterized by increased saccade amplitude in the fixation stability test; diminished saccade velocity in the anti-saccade test; and reduced saccade amplitude, shorter scan path length, lower saccade velocity, decreased dynamic range of pupil size, and lower pupil size ratio in the free-viewing test. Four features mentioned above entered the logistic regression equation. The classification accuracies of SVM, QDA, and BYS models reached 86.0%, 81.1%, and 83.5%, respectively. ConclusionsDepressed patients exhibited abnormalities across multiple tests of eye movements, assisting in differentiating depressed patients from healthy controls in a cost-effective and non-invasive manner.

Effect of scan-path length on the scanning accuracy of completely dentate and partially edentulous maxillae

Statement of problemThe accuracy of fit of fixed partial dentures is directly dependent on the accuracy of a digital scan. However, the influence of scan-path length on scanning accuracy is unclear. PurposeThe purpose of this in vitro study was to evaluate how scan-path length influenced the scanning accuracy of a completely dentate or partially edentulous maxilla captured by 3 intraoral scanners: Omnicam AC (OC), TRIOS 4 (TR), and Primescan (PS). Material and methodsEach intraoral scanner was used to make 30 scans each of the 2 clinical scenarios (completely dentate and partially edentulous) simulated with a reference model. The partially edentulous model simulated a maxilla with 6 prepared teeth to support a complete arch fixed partial denture. The missing teeth were then added to create a completely dentate model. The prepared teeth were later used to determine distance, angular, and tooth-axis deviations between the reference model (digitized with high precision before the tests) and the intraoral scans. Data were statistically analyzed by using a linear model or, if not applicable, a type II ANOVA (α=.05). ResultsDistance deviations increased linearly as the scan-path length increased. In contrast, angular and tooth-axis deviations did not increase linearly. All types of deviation differed depending on the scanning system used. Regarding the 90% quantile values, total distance deviations related to scan-path length amounted to 1.31 μm/mm (OC), 1.00 μm/mm (PS), and 1.45 μm/mm (TR) for the completely dentate maxilla and 1.10 μm/mm (OC), 1.46 μm/mm (PS), and 1.40 μm/mm (TR) for the partially edentulous maxilla. ConclusionsDistance deviations became larger as the scan-path length increased.

What Do You Mean When You Say You Like This Painting? Oculomotor Indices of Processes Involved in Aesthetical Appreciation

This study aims to verify the hypotheses concerning emotional and cognitive predictors of aesthetic judgments, operationalized by instructions for viewing paintings from different perspectives (emotions and feelings, empathy, the captured moment, important elements, title, and mystery). Two eye movement parameters: fixation duration average and scan path length, estimated based on data recorded during viewing paintings, were analyzed. The extent to which the parameters of eye movement while performing different instructions predict the same parameters during the aesthetic assessment task was investigated. It was assumed that similar parameters of eye movements are indicators of similar mental processes, activated under different instructions. The viewing time window and expertise of participants were independent variables. Data were analyzed by multilevel modeling. The results showed that at the early stage of viewing a painting, instructions that activate emotional processing (regardless of expertise), better predict the aesthetic evaluation of a painting than instructions activating cognitive processes. At this stage, it was also found that the eye movement parameters, during the performance of instructions that activate cognitive processing, better predict the aesthetic evaluation of paintings only in the group trained in visual arts. At the later stage of viewing paintings, instructions activating cognitive processes turned out to be more reliable predictors of eye movement parameters during the aesthetic evaluation task than instructions activating emotional processes in both groups of participants. The results of the experiment were confronted with the existing models of perception of art and aesthetic experience.

Sadness-associated eating styles and visual food cue reactivity: An eye-tracking investigation

BackgroundEmotional eating has been associated with biases of attention and memory for visual food cues. This eye-tracking study investigated whether the tendency to overeat in response to sadness is associated with the inspection and recall of visual food cues. MethodParticipants (n = 115, mean age = 26 years, 70 females, 45 males) viewed images depicting food and non-food. We compared gaze duration, ‘hyperscanning’ parameters (fixation duration, saccadic angle, scan path length), and recall performance between different image categories (high-calorie, low-calorie food, non-food) and groups with different sadness-associated eating styles (increased, decreased, unchanged food consumption during states of sadness). ResultsThe group with sadness-related overeating reported a higher body mass index than the other groups, but neither displayed a visual attention bias nor memory bias for food cues. We observed a prolonged gaze duration for low-calorie food cues, which were rated as more appetizing than high-calorie cues. All participants recalled more food cues (low- and high-calorie) than non-food cues independent of gaze duration. ConclusionThis study expanded previous research designs by groups that decrease vs. increase the amount eaten when feeling sad, and food/non-food images that were carefully matched for visual properties. Based on this approach, we were not able to show that self-disclosed sadness eating is associated with visual/memory biases for food images.

Development of an Ergonomic User Interface Design of Calcium Imaging Processing System

An optical brain-machine interface (O-BMI) system using calcium imaging has various advantages such as high resolution, a comprehensive view of large neural populations, abilities such as long-term stable recording, and applicability to freely behaving animals in neuroscience research. The present study developed an ergonomic user interface (UI) design, based on a use scenario for an O-BMI system that can be used for the acquisition and processing of calcium imaging in freely behaving rodents. The UI design was developed in three steps: (1) identification of design and function requirements of users, (2) establishment of a use scenario, and (3) development of a UI prototype. The UI design requirements were identified by a literature review, a benchmark of existing systems, and a focus group interview with five neuroscience researchers. Then, the use scenario was developed for tasks of data acquisition, feature extraction, and neural decoding for offline and online processing by considering the sequences of operations and needs of users. Lastly, a digital prototype incorporating an information architecture, graphic user interfaces, and simulated functions was fabricated. A usability test was conducted with five neuroscientists (work experience = 3.4 ± 1.1 years) and five ergonomic experts (work experience = 3.6 ± 2.7 years) to compare the digital prototypes with four existing systems (Miniscope, nVista, Mosaic, and Suite2p). The usability testing results showed that the ergonomic UI design was significantly preferred to the UI designs of the existing systems by reducing the task completion time by 10.1% to 70.2% on average, the scan path length by 14.4% to 88.7%, and perceived workload by 12.2% to 37.9%, increasing satisfaction by 11.3% to 74.3% in data acquisition and signal-extraction tasks. The present study demonstrates the significance of the user-centered design approach in the development of a system for neuroscience research. Further research is needed to validate the usability test results of the UI prototype as a corresponding real system is implemented.

Frozen with Fear? Attentional Mechanisms in Children with Selective Mutism

BackgroundChildren with selective mutism (SM) are consistently unable to speak in certain social situations. Due to an overlap between SM and social anxiety disorder (SAD) in children, similar mechanisms could apply to both disorders. Especially biased attentional processing of threat and fear-induced reduced visual exploration (referred to as attentive freezing) appear promising in SM.MethodsA total of N = 84 children (8–12 years, SM: n = 28, SAD: n = 28, typical development (TD): n = 28) participated in an eye-tracking paradigm with videos of a social counterpart expressing a question, a social evaluation or a neutral statement. We investigated gaze behavior towards the social counterpart’s eye-region and the extent of visual exploration (length of scanpath), across conditions.ResultsThere were no group differences regarding gaze behavior on the eye region. Neither gaze behavior with respect to the eye region nor visual exploration were dependent on the video condition. Compared to children with TD, children with SM generally showed less visual exploration, however children with SAD did not.ConclusionReduced visual exploration might be due to the mechanism of attentive freezing, which could be part of an extensive fear response in SM that might also affect speech-production. Interventions that counteract the state of freezing could be promising for the therapy of SM.

Efficient Adaptive Surface Measurement Based on Multilevel Gaussian Process Modeling and Scanning Path Optimization

Adaptive surface measurement based on Gaussian process (GP) reduces data redundancy while maintaining the same level of surface reconstruction accuracy as compared with conventional raster scanning. However, the relatively long scanning distance and GP computation time may limit its application when scanning also accounts for the time cost. Toward the simultaneous comprehensive optimization of sampling amount, scanning distance and measurement efficiency, a strategy combining two-level GP modeling and ant colony path planning is proposed. Faster local GP guided sampling along the scanning path is nested to reduce global GP modeling iterations. Experimental results validate that the time-consuming global iterations can be reduced to ~10% of the common GP adaptive method. Compared with raster scanning, without sacrificing the accuracy of surface reconstruction, the sampled data amount, total scanning path length and time cost for measuring a free-form surface are reduced to about 9%, 22% and 13%, respectively. Owing to these prominent advantages, the proposed method has potential applications in efficient and accurate surface measurements.