BRMP-02. Feasibility and evaluation of a novel language paradigm for intraoperative language testing

INTRODUCTION Mapping language during direct cortical stimulation (DCS) in the stetting of awake craniotomy might be challenging without using more than one language paradigm. Applying several language tasks leads to increasing surgery times and to patient’s exhaustion. Additionally, a single language trial must be performed in less than 4 seconds to avoid DCS-induced seizures. Therefore, we aimed to design a single language paradigm which pictures highly relevant language functions and simultaneously restrains the assessment time of single language trials up to 4 seconds. METHOD The intraoperative language task comprised a combination of picture naming and verb generation. During DCS patients should generate correct sentences according to the language stimulus by not exceeding 4 seconds. To assess the intraoperative feasibility of the language task we included 30 healthy subjects in a pilot study to measure subjects’ speed of performing a single language task trial and to evaluate the language paradigm according to its language sensitivity by using the paradigm as a task for functional MRI. Intraoperatively, 21 patients with brain tumors in language associated brain areas were included. Patients received neuropsychological testing before and after surgery. RESULTS The pilot study showed in healthy subjects that by applying the novel paradigm during fMRI there is activation in a left accentuated network of inferior frontal and parietal regions and the superior and middle temporal gyrus (p<.05, FEW). It was feasible to conduct a single language trial of the novel paradigm in a time frame of 4s (performance speed 2.53 s; SD=.32s). Intraoperatively, tumor patients showed DCS-associated language errors while conducting the language task. Postoperatively, mild language but no other neuropsychological deteriorations compared to presurgical assessment were observed (p<.05). CONCLUSION We present a novel language paradigm which safely pictures and monitors highly relevant language functions and consequently can minimize postoperative language deficits.

Rostral Anterior Cingulate Activations Inversely Relate To Reward Payoff Maximation & Predict Depressed Mood

Choice selection strategies and decision making are typically investigated using multiple-choice gambling paradigms that require participants to maximize reward payoff. However, research shows that performance in such paradigms suffers from individual biases towards the frequency of gains to choose smaller local gains over larger longer term gain, also referred to as melioration. Here, we developed a simple two-choice reward task, implemented in 186 healthy human adult subjects across the adult lifespan to understand the behavioral, computational, and neural bases of payoff maximization versus melioration. The observed reward choice behavior on this task was best explained by a reinforcement learning model of differential future reward prediction. Simultaneously recorded and source-localized electroencephalography (EEG) showed that diminished theta-band activations in the right rostral anterior cingulate cortex (rACC) correspond to greater reward payoff maximization, specifically during the presentation of cumulative reward information at the end of each task trial. Notably, these activations (greater rACC theta) predicted self-reported depressed mood symptoms, thereby showcasing a reward processing marker of potential clinical utility.

Clinical feasibility and utility of a dual-task tandem gait protocol for pediatric concussion management

Context: Clinical management of sport-related concussion requires the assessment of various factors, including motor performance. The tandem gait test, a measure of post-injury motor performance, has demonstrated clinical utility, but is limited by time availability and test uniformity. Objective: To assess intrasession reliability between tandem gait test trials and determine the number trials necessary for optimal utility and feasibility in clinical decision-making following concussion. Design: Cross-Sectional Study Setting: Pediatric Sport Medicine Clinic Participants: Adolescent athletes who recently sustained a concussion (n=44; age=15.4±1.8 years; 39% female) and were seen for care within 14 days (7.3±3.2 days) of their injury, as well as uninjured control participants (n=73; age=15.8±1.3 years; 41% female). All participants completed three single-task and three dual-task tandem gait trials. Outcome Measures: We collected test completion time and cognitive performance for each trial and calculated Pearson correlation coefficients between trials and Intraclass Correlation Coefficients to determine intrasession reliability. We also compared performance between groups, and calculated area under the curve (AUC) values to identify the ability of each trial to distinguish between groups. Results: Both the concussion and control group demonstrated high intrasession reliability between tandem gait trials under single (R ≥ 0.82; ICC≥ 0.93) and dual-task conditions (R ≥ 0.79; ICC≥ 0.92). The greatest group classification values were obtained from the second single-task trial (AUC = 0.89) and first dual-task trial (AUC = 0.83). Test completion time provided excellent between-group discrimination in single-task and dual-task conditions. However, cognitive performance during dual-task trials demonstrated only marginally significant clinical utility (AUC ≤ 0.67). Conclusion: Tandem gait assessments may only require two trials under single-task and one trial under dual-task conditions to effectively discriminate between concussion and control groups. This approach may improve the feasibility (time requirement) of the test, while maintaining excellent discriminatory ability.

Exploring the Utility of Subjective Workload Measures for Capturing Dual Task Resource Loading

Our goal was to investigate the impact of dual-tasking on perceived workload, and to study the sensitivity of existing workload measures to components of primary and secondary tasks. Past research has investigated the impact of dual-tasking but has rarely compared the NASA-TLX and the Multiple Resources Questionnaire (MRQ). We made comparisons between workload measures completed after execution of a single-task trial (signal detection task) as compared to a dual-task trial (signal detection accompanied by a secondary auditory task). Special attention was given to comparing the results from the NASA-TLX and the MRQ, along with investigating the sensitivity of the MRQ to specific task components. Facets of the MRQ were analyzed to explore their sensitivity to specific task loading. Results indicate that while both measures reliably registered a change in workload, the MRQ was more sensitive to the source of the change and presented a more holistic picture of cognitive demands.

Simulated Casualty Evacuation Performance Is Augmented by Deadlift Peak Force

Introduction The purpose of the current study was to examine if isometric peak force and rate of force development (RFD) were related to the ability to successfully perform a simulated casualty evacuation task in both unweighted and weighted conditions. Methods Eighteen male participants from Army Reserve Officers’ Training Corps (ROTC) completed a maximum isometric deadlift on a force plate (IRB#HE16227). Isometric peak force and RFD were calculated from ground reaction force. Two simulated casualty evacuation performance trials were then completed. The unweighted trial consisted of lifting and carrying a 75 kg dummy as quickly as possible for 50 m. The weighted trial was similar except 9 kg vests were added to both the simulation dummy and the participant to represent 18 kg of duty gear. Independent sample t-tests and Pearson correlations were performed to compare the characteristics of those who passed and failed the weighted trial. Results All of the participants (n = 18) completed the unweighted casualty evacuation trial, while 72% (n = 13) were able to complete the weighted casualty evacuation trial. The participants that successfully completed the weighted evacuation trial had significantly (p < 0.05) greater isometric peak force (1420 ± 165 vs. 1076 ± 256 N) and lean mass (74.18 ± 3.89 vs. 65.34 ± 3.89 kg) when compared to participants (n = 5) that could not complete the weighted evacuating task trial. Additionally, greater Army Physical Fitness Test scores (288 ± 13 vs. 269 ± 16 arbitrary units) and significantly faster (30.34 ± 4.41 vs. 44.92 ± 10.62 seconds) unweighted evacuation trial times were observed in participants that could complete the weighted evacuation task. Peak force was also significantly correlated with lean mass (r = 0.51, p < 0.05). There was no relationship between RFD and performance of the unweighted or weight trial. Conclusion Isometric deadlift peak force represents an important determinant for the success of a simulated casualty evacuation task and may be a useful marker to include in periodic fitness evaluations of military personnel.

Integrating the Behavioral and Neural Dynamics of Response Selection in a Dual-task Paradigm: A Dynamic Neural Field Model of Dux et al. ()

People are typically slower when executing two tasks than when only performing a single task. These dual-task costs are initially robust but are reduced with practice. Dux et al. ( 2009 ) explored the neural basis of dual-task costs and learning using fMRI. Inferior frontal junction (IFJ) showed a larger hemodynamic response on dual-task trials compared with single-task trial early in learning. As dual-task costs were eliminated, dual-task hemodynamics in IFJ reduced to single-task levels. Dux and colleagues concluded that the reduction of dual-task costs is accomplished through increased efficiency of information processing in IFJ. We present a dynamic field theory of response selection that addresses two questions regarding these results. First, what mechanism leads to the reduction of dual-task costs and associated changes in hemodynamics? We show that a simple Hebbian learning mechanism is able to capture the quantitative details of learning at both the behavioral and neural levels. Second, is efficiency isolated to cognitive control areas such as IFJ, or is it also evident in sensory motor areas? To investigate this, we restrict Hebbian learning to different parts of the neural model. None of the restricted learning models showed the same reductions in dual-task costs as the unrestricted learning model, suggesting that efficiency is distributed across cognitive control and sensory motor processing systems.

Coding of the long-term value of multiple future rewards in the primate striatum

Decisions maximizing benefits involve a tradeoff between the quantity of a reward and the cost of elapsed time until an animal receives it. The estimation of long-term reward values is critical to attain the most desirable outcomes over a certain period of time. Reinforcement learning theories have established algorithms to estimate the long-term reward values of multiple future rewards in which the values of future rewards are discounted as a function of how many steps of choices are necessary to achieve them. Here, we report that presumed striatal projection neurons represent the long-term values of multiple future rewards estimated by a standard reinforcement learning model while monkeys are engaged in a series of trial-and-error choices and adaptive decisions for multiple rewards. We found that the magnitude of activity of a subset of neurons was positively correlated with the long-term reward values, and that of another subset of neurons was negatively correlated throughout the entire decision-making process in individual trials: from the start of the task trial, estimation of the values and their comparison among alternatives, choice execution, and evaluation of the received rewards. An idiosyncratic finding was that neurons showing negative correlations represented reward values in the near future (high discounting), while neurons showing positive correlations represented reward values not only in the near future, but also in the far future (low discounting). These findings provide a new insight that long-term value signals are embedded in two subsets of striatal neurons as high and low discounting of multiple future rewards.

Preschoolers' Responses to Social Comparisons Involving Relative Failure

Prior work indicates that preschoolers (ages 4–5) maintain high self-appraisals and behavioral engagement after performing less well than their peers. This study tested the hypothesis that relative failure has more negative consequences for preschoolers when they interpret achievement differences as being tied to membership in social categories (e.g., when members of different categories have different achievement levels), as opposed to variations in individual effort. Preschoolers ( N = 58) were randomly assigned to receive feedback that a same-gender, other-gender, or gender-unidentified peer performed better than they did on a novel task. Experiences of failure relative to other-gender peers resulted in impaired performance on a subsequent task trial, as well as lack of improvement in self-evaluations after children received more positive feedback. These findings have implications for the origins of social comparisons, category-based reasoning, and the development of gender stereotypes and achievement motivation.

Changes in EEG Rhythms during Television Viewing: Preliminary Comparisons with Reading and other Tasks

The purpose of this study was to provide preliminary data for comparing EEG activity during television viewing with EEG during reading and other tasks commonly used in psychophysiological research. EEG was recorded from left and right occipital locations in 18 subjects and a 2 × 2 × 6 × 5 (sex × site × task × trial) mixed factorial design was used in the analysis of alpha and beta EEG. Significant task effects were obtained for both alpha and beta scores and internal analyses indicated that the highest levels of beta and the lowest amounts of alpha were associated with the two tasks (reading and TV) which presented participants with specific patterns of sensory stimulation whereas tasks calling for mental relaxation (eyes open and eyes closed) and tasks requiring only mental operations (imagine and counting) were associated with lower beta levels and higher alpha. Although not statistically significant, more beta activity was observed during reading than during TV and more alpha was observed during TV than during reading. No main effects or interaction terms involving sex differences or hemispheric effects were significant.