Vigilance and Automation Dependence in Operation of Multiple Unmanned Aerial Systems (UAS): A Simulation Study.

OBJECTIVE: This simulation study investigated factors influencing sustained performance and fatigue during operation of multiple Unmanned Aerial Systems (UAS). The study tested effects of time-on-task and automation reliability on accuracy in surveillance tasks and dependence on automation. It also investigated the role of trait and state individual difference factors. BACKGROUND: Warm's resource model of vigilance has been highly influential in human factors, but further tests of its applicability to complex, real-world tasks requiring sustained attention are necessary. Multi-UAS operation differs from standard vigilance paradigms in that the operator must switch attention between multiple subtasks, with support from automation. METHOD: 131 participants performed surveillance tasks requiring signal discrimination and symbol counting with a multi-UAS simulation configured to impose low cognitive demands, for 2 hr. Automation reliability was manipulated between-groups. Five Factor Model personality traits were measured prior to performance. Subjective states were assessed with the Dundee Stress State Questionnaire. RESULTS: Performance accuracy on the more demanding surveillance task showed a vigilance decrement, especially when automation reliability was low. Dependence on automation on this task declined over time. State but not trait factors predicted performance. High distress was associated with poorer performance in more demanding task conditions. CONCLUSIONS: Vigilance decrement may be an operational issue for multi-UAS surveillance missions. Warm's resource theory may require modification to incorporate changes in information processing and task strategy associated with multitasking in low-workload, fatiguing environments. APPLICATION: Interface design and operator evaluation for multi-UAS operations should address issues including motivation, stress, and sustaining attention to automation.

Emotion labeling and socio-emotional outcomes 18 months after early childhood traumatic brain injury.

A growing body of literature has documented evidence for emotion labeling (EL) deficits after traumatic brain injury (TBI); however, long-term effects of TBI on EL abilities, particularly among young children, are unclear. We investigated EL abilities and socio-emotional outcomes in 32 children with moderate-severe TBI, 23 with complicated-mild TBI, and 82 children with orthopedic injuries (OI), shortly after injury and at 18 months post-injury. All children were between 3:0 and 6:11 years of age at the time of injury. Repeated measures analyses indicated that all groups showed improved EL performance between acute and 18-month assessments, but that the moderate-severe TBI group improved at a slower rate than the OI group, so that the two groups showed significantly different performance at 18 months. Emotion labeling ability did not significantly contribute to the prediction of socio-emotional outcomes after controlling for pre-injury functioning. These results provide preliminary evidence of emerging EL deficits after early childhood TBI that are related to injury severity but that do not predict social and behavioral outcomes.

Neural correlates of interference control in adolescents with traumatic brain injury: functional magnetic resonance imaging study of the counting stroop task.

Difficulty in inhibition or cognitive control is a common and significant sequela of pediatric traumatic brain injury (TBI). The present study used functional MRI to examine one specific inhibitory function, interference control, in 11 adolescents, aged 12-16 years, (mean age, 15.7 years) with TBI who were at least 1 year postinjury and 11 age-matched typically developing control participants (TC) (mean age, 15.2 years). Participants completed a Counting Stroop task with 2 main conditions: (1) a neutral condition requiring the counting of animal words and (2) an interference condition in which mismatched number words were counted. Both TBI and TC adolescents activated similar networks of brain regions relevant to interference control, but the TBI group showed higher levels of activation relative to the TC group in multiple brain areas within this network, including predominantly right frontal and parietal regions. Findings of greater activation of the relevant neural network in the TBI group are consistent with recent fMRI findings using other interference control paradigms with individuals with a history of TBI.

The effect of temperament and neuropsychological functioning on behavior problems in children with new-onset seizures.

The present study is part of a larger project that seeks to identify factors that predict children's behavioral, social, and cognitive adaptation to epilepsy. Children with seizures are more likely to have internalizing and externalizing behavior problems than either healthy children or children with other chronic illnesses. The present research examines risk factors for behavior problems. Early temperament and neuropsychological functioning, specifically executive function and language abilities, are evaluated as unique and moderating predictors of adverse behavioral outcomes in 229 children with a first recognized seizure. Parents assessed temperament, children were administered neuropsychological tests, and teachers evaluated behavior 36 months after seizure onset. Results revealed that early temperament and neuropsychological functioning, specifically executive function, predicted behavioral outcomes 3 years after seizure onset.

Long-term neural processing of attention following early childhood traumatic brain injury: fMRI and neurobehavioral outcomes.

Attentional deficits are common and significant sequelae of pediatric traumatic brain injury (TBI). However, little is known about how the underlying neural processes that support different components of attention are affected. The present study examined brain activation patterns using fMRI in a group of young children who sustained a TBI in early childhood (n = 5; mean age = 9.4), and a group of age-matched control children with orthopedic injuries (OI) (n = 8) during a continuous performance task (CPT). Four children in the TBI group had moderate injuries, and one had a severe injury. Performance on the CPT task did not differ between groups. Both TBI and OI children activated similar networks of brain regions relevant to sustained attention processing, but the TBI group demonstrated several areas of significantly greater activation relative to controls, including frontal and parietal regions. These findings of over-activation of the relevant attention network in the TBI group contrast with those obtained in imaging studies of Attention-Deficit/Hyperactivity Disorder where under-activation of the attention network has been documented. This study provides evidence that young children's brains function differently following a traumatic brain injury, and that these differences persist for years after the injury.

Postural responses to specific types of working memory tasks.

Standing participants performed working memory tasks that varied along three dimensions: (1) type of information presented (verbal or visual); (2) the primary cognitive process engaged (encoding or rehearsal); and (3) interference that targeted the working memory components (phonological loop and visual sketchpad) believed primarily active during rehearsal. Postural sway variability decreased during rehearsal and increased during encoding. The effects during encoding, but not during rehearsal, differed for verbal versus visual material. Changes in cognitive activity were also associated with changes in the temporal patterns of postural sway. The results suggest postural control is sensitive to the type of cognitive task performed.

Neural correlates of memory development and learning: combining neuroimaging and behavioral measures to understand cognitive and developmental processes.

This special issue includes 4 articles addressing the general theme of neural correlates of memory development and learning. Taken together, the articles represent a broad range of development, including infants, children, adolescents, and adults as participants. Each line of research examines relations between brain activity and cognitive functions using both physiological measures, event-related potentials or functional magnetic resonance imaging, and behavioral measures of memory and learning. This introduction sets the stage by briefly reviewing historical trends in memory development research, discussing major issues associated with neuroimaging research, and providing an integrated perspective of some specific contributions of the investigations included in this special issue, arguing that combining neuroimaging and behavioral measures advances research on memory development and learning in terms of understanding cognitive and developmental processes. The article concludes with a brief discussion of potential future directions for this type of research.

Making memories: a cross-sectional investigation of episodic memory encoding in childhood using FMRI.

In adults, the neural substrate associated with encoding memories connected to a specific time and place include the prefrontal cortex and medial temporal lobe (MTL). Using functional magnetic resonance imaging, this research studied the developmental trajectory of this frontal-MTL system by comparing 7- and 8-year-old children to those who were 10 or older in conditions that promoted episodic encoding. In 1 condition, participants generated verbs from nouns heard; in another, they listened to short stories for comprehension. Regions in which brain activation predicted subsequent recognition memory performance were identified. These included the left prefrontal cortex, but not MTL, in the verb generation condition for both age groups. In the story comprehension condition, activation in left posterior MTL predicted subsequent memory performance in both age groups, and activation in left anterior MTL (including the hippocampus proper) and left prefrontal cortex predicted subsequent memory only for the older children. These results illustrate both similarities and differences in how brain systems interact in development to mediate the formation of episodic memories.

Sound blending in the brain: a functional magnetic resonance imaging investigation.

The presence of high levels of background noise is a serious concern for functional magnetic resonance imaging studies of phonological processing using conventional methods. As a result, many such studies have focused on phonological units larger than phonemes (e.g. syllables) or used stimuli presented in the visual (e.g. printed letters) rather than the auditory domain. We used a recently developed functional magnetic resonance imaging method to present spoken stimuli without the scanner's background noise. Young adult participants mentally blended phonemes in a series (e.g. /b/, /ae/, /t/), counted the number of discrete tones, or rested. Relative to tone counting, sound blending elicited activation in bilateral temporal and prefrontal cortices with left asymmetry. Activation within the dorsoposterior inferior frontal gyrus, a subregion of Broca's area, was negatively correlated with sound-blending accuracy. Our findings are consistent with prior studies ascribing a role of general sequencing, motor and articulatory programming, and vocal or subvocal articulatory rehearsal to this brain region.

Neural correlates of risky decision making in adolescents with and without traumatic brain injury using the balloon analog risk task.

We studied risky decision making (RDM) in 8 healthy adolescents (TC) and 11 adolescents with mild to moderate traumatic brain injuries (TBI) using the Balloon Analog Risk Task (BART) and functional magnetic resonance imaging (fMRI). Participants inflated simulated balloons (with more points awarded to bigger balloons), which might burst at any time. Increasing brain activation levels were associated with increasing balloon size in a largely bilateral network, including cerebellar, inferior parietal, limbic, and frontal areas. Both groups performed similarly and activated similar networks.

Neural correlates of verbal associative memory and mnemonic strategy use following childhood traumatic brain injury.

Children with traumatic brain injury (TBI) often experience memory deficits, although the nature, functional implication, and recovery trajectory of such difficulties are poorly understood. The present fMRI study examined the neural activation patterns in a group of young children who sustained moderate TBI in early childhood (n = 7), and a group of healthy control children (n = 13) during a verbal paired associate learning (PAL) task that promoted the use of two mnemonic strategies differing in efficacy. The children with TBI demonstrated intact memory performance and were able to successfully utilize the mnemonic strategies. However, the TBI group also demonstrated altered brain activation patterns during the task compared to the control children. These findings suggest early childhood TBI may alter activation within the network of brain regions supporting associative memory even in children who show good behavioral performance.