Neurophysiological Metrics Research Articles

EFFECTIVE USE OF PHYSIOLOGICAL METRICS TO ASSESS USER EMOTION AND BEHAVIOR INTENTION BASED ON AN EYE TRACKER AND NEUROPHYSIOLOGICAL APPROACH

Products are successfully designed only when they are in accord with the users’ emotional needs. A systematic research approach is aimed to propose that physiological metrics can be effectively used to assess user emotion and behavior intention based on an eye tracker and neurophysiological approach. Forty participants (20 males and 20 females, mean age=35.6, SD=6.38, range 21-48 years), were recruited from college campuses and communities to conduct an eye tracker and electroencephalography (EEG) experiment with the presented stimuli (images of SUVs). The study uses partial least squares structural equation modeling (PLS-SEM) to test the model hypotheses. The results show a strong and significant relationship between eye tracker metrics, neurophysiological metrics, user affective responses, and behavior intention. These findings could enable industrial counselors, professional product designers, and academics to categorize users’ emotional needs that can be subsequently incorporated into final product design.

Your Brain on the Movies: A Computational Approach for Predicting Box-office Performance from Viewer's Brain Responses to Movie Trailers.

The ability to anticipate the population-wide response of a target audience to a new movie or TV series, before its release, is critical to the film industry. Equally important is the ability to understand the underlying factors that drive or characterize viewer’s decision to watch a movie. Traditional approaches (which involve pilot test-screenings, questionnaires, and focus groups) have reached a plateau in their ability to predict the population-wide responses to new movies. In this study, we develop a novel computational approach for extracting neurophysiological electroencephalography (EEG) and eye-gaze based metrics to predict the population-wide behavior of movie goers. We further, explore the connection of the derived metrics to the underlying cognitive processes that might drive moviegoers’ decision to watch a movie. Towards that, we recorded neural activity—through the use of EEG—and eye-gaze activity from a group of naive individuals while watching movie trailers of pre-selected movies for which the population-wide preference is captured by the movie’s market performance (i.e., box-office ticket sales in the US). Our findings show that the neural based metrics, derived using the proposed methodology, carry predictive information about the broader audience decisions to watch a movie, above and beyond traditional methods. In particular, neural metrics are shown to predict up to 72% of the variance of the films’ performance at their premiere and up to 67% of the variance at following weekends; which corresponds to a 23-fold increase in prediction accuracy compared to current neurophysiological or traditional methods. We discuss our findings in the context of existing literature and hypothesize on the possible connection of the derived neurophysiological metrics to cognitive states of focused attention, the encoding of long-term memory, and the synchronization of different components of the brain’s rewards network. Beyond the practical implication in predicting and understanding the behavior of moviegoers, the proposed approach can facilitate the use of video stimuli in neuroscience research; such as the study of individual differences in attention-deficit disorders, and the study of desensitization to media violence.

Evaluation of Functional Correlation of Task-Specific Muscle Synergies with Motor Performance in Patients Poststroke.

The central nervous system produces movements by activating specifically programmed muscle synergies that are also altered with injuries in the brain, such as stroke. In this study, we hypothesize that there exists a positive correlation between task-specific muscle synergy and motor functions at joint and task levels in patients following stroke. The purpose here is to define and evaluate neurophysiological metrics based on task-specific muscle synergy for assessing motor functions in patients. A patient group of 10 subjects suffering from stroke and a control group of nine age-matched healthy subjects were recruited to participate in this study. Electromyography (EMG) signals and movement kinematics were recorded in patients and control subjects while performing arm reaching tasks. Muscle synergies of individual patients were extracted off-line from EMG records of each patient, and a baseline pattern of muscle synergy was obtained from the pooled EMG data of all nine control subjects. Peak velocities and movement durations of each reaching movement were computed from measured kinematics. Similarity indices of matching components to those of the baseline synergy were defined by synergy vectors and time profiles, respectively, as well as by a combined similarity of vector and time profile. Results showed that pathological synergies of patients were altered from the characteristics of baseline synergy with missing components, or varied vector patterns and time profiles. The kinematic performance measured by peak velocities and movement durations was significantly poorer for the patient group than the control group. In patients, all three similarity indices were found to correlate significantly to the kinematics of movements for the reaching tasks. The correlation to the Fugl-Meyer score of arm was the highest with the vector index, the lowest with the time profile index, and in between with the combined index. These findings illustrate that the analysis of task-specific muscle synergy can provide valuable insights into motor deficits for patients following stroke, and the task-specific similarity indices are useful neurophysiological metrics to predict the function of neuromuscular control at the joint and task levels for patients.

Behavioral and Neural Correlates of Executive Function: Interplay between Inhibition and Updating Processes.

This study investigated the interaction between two executive function processes, inhibition and updating, through analyses of behavioral, neurophysiological, and effective connectivity metrics. Although, many studies have focused on behavioral effects of executive function processes individually, few studies have examined the dynamic causal interactions between these two functions. A total of twenty participants from a local university performed a dual task combing flanker and n-back experimental paradigms, and completed the Operation Span Task designed to measure working memory capacity. We found that both behavioral (accuracy and reaction time) and neurophysiological (P300 amplitude and alpha band power) metrics on the inhibition task (i.e., flanker task) were influenced by the updating load (n-back level) and modulated by working memory capacity. Using independent component analysis, source localization (DIPFIT), and Granger Causality analysis of the EEG time-series data, the present study demonstrated that manipulation of cognitive demand in a dual executive function task influenced the causal neural network. We compared connectivity across three updating loads (n-back levels) and found that experimental manipulation of working memory load enhanced causal connectivity of a large-scale neurocognitive network. This network contains the prefrontal and parietal cortices, which are associated with inhibition and updating executive function processes. This study has potential applications in human performance modeling and assessment of mental workload, such as the design of training materials and interfaces for those performing complex multitasking under stress.

Human Factors and Neurophysiological Metrics in Air Traffic Control: A Critical Review.

This paper provides a focused and organized review of the research progress on neurophysiological indicators, also called "neurometrics," to show how they can effectively address some of the most important human factors (HFs) needs in the air traffic management (ATM) field. In order to better understand and highlight available opportunities of such neuroscientific applications, state of the art on the most involved HFs and related cognitive processes (e.g., mental workload and cognitive training) are presented together with examples of possible applications in current and future ATM scenarios. Furthermore, this paper will discuss the potential enhancements that further research and development activities could bring to the efficiency and safety of the ATM service.

Reliability of TMS metrics in patients with chronic incomplete spinal cord injury.

Test-retest reliability analysis in individuals with chronic incomplete spinal cord injury (iSCI). The purpose of this study was to examine the reliability of neurophysiological metrics acquired with transcranial magnetic stimulation (TMS) in individuals with chronic incomplete tetraplegia. Cleveland Clinic Foundation, Cleveland, Ohio, USA. TMS metrics of corticospinal excitability, output, inhibition and motor map distribution were collected in muscles with a higher MRC grade and muscles with a lower MRC grade on the more affected side of the body. Metrics denoting upper limb function were also collected. All metrics were collected at two sessions separated by a minimum of two weeks. Reliability between sessions was determined using Spearman's correlation coefficients and concordance correlation coefficients (CCCs). We found that TMS metrics that were acquired in higher MRC grade muscles were approximately two times more reliable than those collected in lower MRC grade muscles. TMS metrics of motor map output, however, demonstrated poor reliability regardless of muscle choice (P=0.34; CCC=0.51). Correlation analysis indicated that patients with more baseline impairment and/or those in a more chronic phase of iSCI demonstrated greater variability of metrics. In iSCI, reliability of TMS metrics varies depending on the muscle grade of the tested muscle. Variability is also influenced by factors such as baseline motor function and time post SCI. Future studies that use TMS metrics in longitudinal study designs to understand functional recovery should be cautious as choice of muscle and clinical characteristics can influence reliability.

Suboptimal Use of Neural Information in a Mammalian Auditory System

Establishing neural determinants of psychophysical performance requires both behavioral and neurophysiological metrics amenable to correlative analyses. It is often assumed that organisms use neural information optimally, such that any information available in a neural code that could improve behavioral performance is used. Studies have shown that detection of amplitude-modulated (AM) auditory tones by humans is correlated to neural synchrony thresholds, as recorded in rabbit at the level of the inferior colliculus, the first level of the ascending auditory pathway where neurons are tuned to AM stimuli. Behavioral thresholds in rabbit, however, are ∼10 dB higher (i.e., 3 times less sensitive) than in humans, and are better correlated to rate-based than temporal coding schemes in the auditory midbrain. The behavioral and physiological results shown here illustrate an unexpected, suboptimal utilization of available neural information that could provide new insights into the mechanisms that link neuronal function to behavior.

Use of Neurophysiological Metrics Within a Real and Virtual Perceptual Skills Task to Assess Virtual Training Environment Fidelity Requirements

Both military and civilian virtual environment (VE) developers are increasingly looking to cognitive scientists to provide virtual training platforms to support optimal training effectiveness within significant time and cost constraints. A need exists for objective and efficient methods of identifying optimal fidelity characteristics to support transfer of training. Previous research has demonstrated that brain eventrelated potentials (ERP’s) are sensitive to slight variations in virtual task environment fidelity, even in cases in which task performance does not significantly differ. The current experiment compared physiological and performance data for subjects completing a real-world perceptual discrimination task, as well as a similarly-structured VE training task under systematically varied fidelity conditions, in an effort to characterize the impact ofthe various conditions. Significant differences were found for task condition (real world versus virtual, as well as visual stimulus parameters within each condition), within both the performance and physiological data.

A neurophysiological and behavioral investigation of tactile spatial exploration for sighted and non-sighted adults

In this work we report on preliminary results about a new method to evaluate the cues used for constructing mental maps of virtual objects, presented through interaction with a tactile device. Both behavioral and neurophysiological metrics are considered to evaluate the process of identifying virtual structures, in both sighted and non-sighted adults. The possible dependency on the kind of virtual object or on the sensory impairment is investigated. Results also show similarities between sighted and non-sighted subjects in the identification process. Our method may facilitate researchers in understanding and assessing human-system integration in the context of touch-based interfaces for non-sighted people. Language: en

The Physiological Assessment of VE Training System Fidelity

This paper describes the Training Effectiveness Evaluation with neurophysiological metrics: Fidelity Assessment of VE Training Systems (TEE-FAST) framework, which offers a comprehensive assessment of physical, functional and psychological fidelity of VE training systems. TEE-FAST evaluates at the cue level how information is presented to users and how users respond, both behaviorally and physiologically, in both a VE training environment and the related operational (or live training) environment. The differences in cue presentation and user responses across VE and live tasks are evaluated to determine how effective a VE training system is at targeting specified training goals. Evaluation outcomes provide targeted design guidance regarding training utility related to each specified training goal, as well as redesign recommendations to enhance VE system fidelity and training utility.