Emotional, physiological, biochemical, and behavioral responses to acute stress and uncertainty in military personnel.

Stress carries diverse implications for perceptual, cognitive, and affective functions. One population particularly susceptible to acute stress-induced cognitive changes are individuals with high-stress jobs (e.g.

Trait-level predictors of human performance outcomes in personnel engaged in stressful laboratory and field tasks.

Introduction: Personnel performance under stress hinges on various factors, including individual traits, training, context, mental and physiological states, and task demands. This study explored the link between the traits of military personnel and their performance outcomes in five domains: move, shoot, communicate, navigate, and sustain.

Methods: A total of 387 U.

Characterizing Relationships Among the Cognitive, Physical, Social-emotional, and Health-related Traits of Military Personnel.

Introduction: Personnel engaged in high-stakes occupations, such as military personnel, law enforcement, and emergency first responders, must sustain performance through a range of environmental stressors. To maximize the effectiveness of military personnel, an a priori understanding of traits can help predict their physical and cognitive performance under stress and adversity. This work developed and assessed a suite of measures that have the potential to predict performance during operational scenarios.

Electrophysiological correlates of perceptual prediction error are attenuated in dyslexia.

A perceptual adaptation deficit often accompanies reading difficulty in dyslexia, manifesting in poor perceptual learning of consistent stimuli and reduced neurophysiological adaptation to stimulus repetition. However, it is not known how adaptation deficits relate to differences in feedforward or feedback processes in the brain. Here we used electroencephalography (EEG) to interrogate the feedforward and feedback contributions to neural adaptation as adults with and without dyslexia viewed pairs of faces and words in a paradigm that manipulated whether there was a high probability of stimulus repetition versus a high probability of stimulus change.

ERP Mismatch Negativity Amplitude and Asymmetry Reflect Phonological and Rapid Automatized Naming Skills in English-Speaking Kindergartners.

The mismatch negativity (MMN), an electrophysiological response to an oddball auditory stimulus, is related to reading ability in many studies. There are conflicting findings regarding exactly how the MMN relates to risk or actual diagnosis of dyslexia/reading impairment, perhaps due to the heterogeneity of abilities in children with reading impairment. In this study, 166 English-speaking kindergarten children oversampled for dyslexia risk completed behavioral assessments and a speech-syllable MMN paradigm.

Load Carriage and Physical Exertion Influence Cognitive Control in Military Scenarios.

Introduction: Physical exertion has both beneficial and detrimental effects on cognitive performance, particularly cognitive control. Research into physical exertion under conditions of load carriage is particularly important given that military personnel and first responders must perform optimally under such combinatorial physical stressors. The present work sought to characterize cognitive control as a function of physical exertion and load carriage in a military operational scenario.

Endurance Exercise Enhances Emotional Valence and Emotion Regulation.

Acute exercise consistently benefits both emotion and cognition, particularly cognitive control. We evaluated acute endurance exercise influences on emotion, domain-general cognitive control and the cognitive control of emotion, specifically cognitive reappraisal. Thirty-six endurance runners, defined as running at least 30 miles per week with one weekly run of at least 9 miles (21 female, age 18-30 years) participated.

Exerting cognitive control under threat: Interactive effects of physical and emotional stress.

Individuals with stressful occupations, such as law enforcement and military personnel, are required to operate in high stakes environments that can be simultaneously physically and emotionally demanding. These individuals are tasked with maintaining peak performance under stressful and often unpredictable conditions, exerting high levels of cognitive control to sustain attention and suppress task-irrelevant actions. Previous research has shown that physical and emotional stressors differentially influence such cognitive control processes.

Different profiles of decision making and physiology under varying levels of stress in trained military personnel.

Decision making is one of the most vital processes we use every day, ranging from mundane decisions about what to eat to life-threatening choices such as how to avoid a car collision. Thus, the context in which our decisions are made is critical, and our physiology enables adaptive responses that account for how environmental stress influences our performance. The relationship between stress and decision making can additionally be affected by one's expertise in making decisions in high-threat environments, where experts can develop an adaptive response that mitigates the negative impacts of stress.

Habitual exercise is associated with cognitive control and cognitive reappraisal success.

Habitual exercise is associated with enhanced domain-general cognitive control, such as inhibitory control, selective attention, and working memory, all of which rely on the frontal cortex. However, whether regular exercise is associated with more specific aspects of cognitive control, such as the cognitive control of emotion, remains relatively unexplored. The present study employed a correlational design to determine whether level of habitual exercise was related to performance on the Stroop test measuring selective attention and response inhibition, the cognitive reappraisal task measuring cognitive reappraisal success, and associated changes in prefrontal cortex (PFC) oxygenation using functional near-infrared spectroscopy.

Cognitive strategies in the mental rotation task revealed by EEG spectral power.

The classic mental rotation task (MRT; Shepard & Metzler, 1971) is commonly thought to measure mental rotation, a cognitive process involving covert simulation of motor rotation. Yet much research suggests that the MRT recruits both motor simulation and other analytic cognitive strategies that depend on visuospatial representation and visual working memory (WM). In the present study, we investigated cognitive strategies in the MRT using time-frequency analysis of EEG and independent component analysis.

Masked priming for the comparative evaluation of camouflage conspicuity.

Human observer test and evaluation of camouflage patterns is critical for understanding relative pattern conspicuity against a range of background scenes. However, very few validated methodologies exist for this purpose, and those that do carry several limitations. Five experiments examined whether masked priming with a dot probe could be used to reliably differentiate camouflage patterns.

Development of sensitivity versus specificity for print in the visual word form area.

An area near the left lateral occipito-temporal sulcus that responds preferentially to print has been designated as the visual word form area (VWFA). Research suggests that specialization in this brain region increases as reading expertise is achieved. Here we aimed to characterize that development in terms of sensitivity (response to printed words relative to non-linguistic faces) versus specificity (response to printed words versus line drawings of nameable objects) in typically reading children ages 7-14 versus young adults as measured by functional magnetic resonance imaging (fMRI).

Orthographic and phonological processing in developing readers revealed by ERPs.

The development of neurocognitive mechanisms in single word reading was studied in children ages 8-10 years using ERPs combined with priming manipulations aimed at dissociating orthographic and phonological processes. Transposed-letter (TL) priming (barin-BRAIN vs. bosin-BRAIN) was used to assess orthographic processing, and pseudohomophone (PH) priming (brane-BRAIN vs.

Pupil diameter changes reflect difficulty and diagnostic accuracy during medical image interpretation.

Background: No automated methods exist to objectively monitor and evaluate the diagnostic process while physicians review computerized medical images. The present study tested whether using eye tracking to monitor tonic and phasic pupil dynamics may prove valuable in tracking interpretive difficulty and predicting diagnostic accuracy.

Methods: Pathologists interpreted digitized breast biopsies varying in diagnosis and rated difficulty, while pupil diameter was monitored.

The effect of a brief mindfulness induction on processing of emotional images: an ERP study.

The ability to effectively direct one's attention is an important aspect of regulating emotions and a component of mindfulness. Mindfulness practices have been established as effective interventions for mental and physical illness; however, the underlying neural mechanisms of mindfulness and how they relate to emotional processing have not been explored in depth. The current study used a within-subjects repeated measures design to examine if focused breathing, a brief mindfulness induction, could modulate event-related potentials (ERPs) during emotional image processing relative to a control condition.

The Effects of Load Carriage and Physical Fatigue on Cognitive Performance.

In the current study, ten participants walked for two hours while carrying no load or a 40 kg load. During the second hour, treadmill grade was manipulated between a constant downhill or changing between flat, uphill, and downhill grades. Throughout the prolonged walk, participants performed two cognitive tasks, an auditory go no/go task and a visual target detection task.

Increasing breadth of semantic associations with left frontopolar direct current brain stimulation: a role for individual differences.

The aim of this study was to evaluate the influence of left frontopolar versus auditory (control) cortex transcranial direct current stimulation (tDCS) on the breadth of semantic associations produced in a cued free association task. A within-participants design administered anodal tDCS over the left frontopolar or auditory cortex, centered at electrode site AFZ or T7 using a 4×1 targeted stimulation montage. During stimulation, participants produced free associates in response to cues designed to promote narrow, moderate, or broad semantic associations.

Acute exercise increases oxygenated and deoxygenated hemoglobin in the prefrontal cortex.

Both acute and chronic exercise is consistently associated with a number of benefits to physical and mental health, including cardiovascular function, body weight, mood, and cognition. Near-infrared spectroscopy is an ideal method to measure changes in oxygenated and deoxygenated hemoglobin (O2Hb and dHb) levels in the prefrontal cortex (PFC) during exercise, to better understand the locus of such changes in affective and cognitive processes. The present study tracked time-dependent changes in O2Hb and dHb levels in the PFC as a function of parametrically manipulated target exercise intensity.

Direct current brain stimulation enhances navigation efficiency in individuals with low spatial sense of direction.

The aim of this study was to evaluate the influence of right versus left temporal transcranial direct current stimulation (tDCS) on navigation efficiency and spatial memory in individuals with low versus high spatial skills. A mixed design administered low (0.5 mA) versus high (2.

Neural correlates of letter reversal in children and adults.

Children often make letter reversal errors when first learning to read and write, even for letters whose reversed forms do not appear in normal print. However, the brain basis of such letter reversal in children learning to read is unknown. The present study compared the neuroanatomical correlates (via functional magnetic resonance imaging) and the electrophysiological correlates (via event-related potentials or ERPs) of this phenomenon in children, ages 5-12, relative to young adults.

Masked priming and ERPs dissociate maturation of orthographic and semantic components of visual word recognition in children.

This study examined the time-course of reading single words in children and adults using masked repetition priming and the recording of event-related potentials. The N250 and N400 repetition priming effects were used to characterize form- and meaning-level processing, respectively. Children had larger amplitude N250 effects than adults for both shorter and longer duration primes.

Variable transmission lens influences on the dynamics of pupillary light reflexes.

This study examined the influence of liquid crystal variable transmission lenses on pupillary light reflexes in response to sudden bright light onset. Participants were exposed to bright light while pupil size was monitored using an eye tracker; eyewear was configured across four transition conditions: constant low-light filtering, constant high-light filtering, variable-light filtering in response to light detection and a control condition without eyewear. Before light onset, pupil diameter was largest in the high-filter condition, medium in the variable- and low-light filtering conditions and smallest in the control condition.

Invariance to rotation in depth measured by masked repetition priming is dependent on prime duration.

The current experiment examined invariance to pictures of objects rotated in depth using event-related potentials (ERPs) and masked repetition priming. Specifically we rotated objects 30°, 60° or 150° from their canonical view and, across two experiments, varied the prime duration (50 or 90 ms). We examined three ERP components, the P/N190, N300 and N400.