Higher landing accuracy in expert pilots is associated with lower activity in the caudate nucleus

Effects of age and flight experience on prefrontal cortex activity in airline pilots: An fNIRS study

It is essential for airlines to have a deep understanding of the cognitive impact of aging among pilots. The current literature on executive function indicates that compensatory mechanisms in the brain may counteract age-related cognitive decline, at least up to certain task load levels. However, few studies have been administered to evaluate changes in aircrew competence as they age. The present study focuses on dorsolateral prefrontal cortex (DLPFC) activity as it is implicated in cognitive performance and working memory, which are associated with skill proficiency. We measured the DLPFC activity for airline pilots, including trainees, during maneuvering using a flight simulator. Our preliminary results indicated that only expert (aged) pilots demonstrated higher activity of the left DLPFC than the right one. However, for youth trainees, not only was the error rate high while using the flight simulator, but the activity of the DLFPC was also lower than that of the expert pilots, and there was no statistically significant difference between the left and right DLPFC. Although these findings partially differ from those reported in previous studies on age-related changes, it is evident that training as an airline pilot for over 20 years may affect such results. We believe that this noninvasive approach to objective quantification of skill will facilitate the development of effective assessment competence in aging.

Research on brain functions related to visual information processing and body coordination function of pilots based on the low-frequency amplitude method

Objective

Research on the differences in physiological and psychological mechanisms of practitioners in different occupations is a current hot spot, such as pilots. This study explores the frequency-dependent changes of pilots' low-frequency amplitudes in the classical frequency band and sub-frequency band between pilots and general occupations. The goal of the current work is to provide objective brain images for the selection and evaluation of outstanding pilots.

Methods

Twenty-six pilots and 23 age-, sex-, and education-matched healthy controls were included in this study. Then the mean low-frequency amplitude (mALFF) of the classical frequency band and sub-frequency band was calculated. The two-sample t-test was performed on SPM12 to analyze the differences between the flight group and control group in the classic frequency band. To explore the main effects and the inter-band effects of the mean low-frequency amplitude (mALFF), the mixed design analysis of variance was applied in the sub-frequency bands.

Results

Compared with the control group, left cuneiform lobe and the right cerebellum six area of pilots show significant difference in the classic frequency band. And the main effect results in the sub-frequency bands show that the area with higher mALFF in the flight group is located on the left middle occipital gyrus, the left cuneiform lobe, the right superior occipital gyrus, the right superior gyrus, and the left lateral central lobule. However, the area where the value of mALFF decreased is mainly located on the left rectangular cleft with surrounding cortex and the right dorsolateral superior frontal gyrus. Besides, compared with the slow-4 frequency band, the mALFF of the left middle orbital middle frontal gyrus of the slow-5 frequency band was increased, while the mALFF value of the left putamen, left fusiform gyrus, and right thalamus was decreased. The sensitivity of the slow-5 frequency band and the slow-4 frequency band to the pilots' different brain areas was also different. Also, the different brain areas in the classic frequency band and the sub-frequency band were significantly correlated with pilots' flight hours.

Conclusion

Our findings showed that the left cuneiform brain area and the right cerebellum of pilots changed significantly during resting state. And there was a positive correlation between the mALFF value of those brain area and flight hours. The comparative analysis of sub-frequency bands found that the slow-5 band could elucidate a wider range of different brain regions, providing new ideas for exploring the brain mechanisms of pilots.

Intraocular pressure responses to a virtual reality shooting simulation in active-duty members of the Spanish Army: The influence of task complexity

Ocular physiology is sensitive to cognitively demanding tasks. However, it is unknown whether the intraocular pressure is also affected by the cognitive demands of military operations. The main objective was to determine the impact of a virtual reality shooting simulation with two levels of complexity on intraocular pressure levels in military personnel. Eighteen active-duty members of the Spanish Army and eighteen civilians performed two 4 min simulated shooting tasks with two levels of complexity using a virtual reality. In the "easy" task participants performed a simulated shoot when the stimulus (military with a rifle) appeared, while in the "difficult" task the stimulus randomly was a military with a rifle or with his hands on the air and participants were instructed to respond only when the military with a rifle appeared. Intraocular pressure was measured with a rebound tonometer before and immediately after each task. Complementarily, perceived levels of mental load and shooting performance (reaction time) were assessed. Intraocular pressure was greater after completing the more complex task in both military personnel (p-value < 0.01, Cohen´s d = 1.19) and civilians (p-value < 0.01, Cohen´s d = 1.16). Also, perceived levels of task load and reaction time were higher in the difficult compared to the easy shooting tasks (both p < 0.001). The rise in intraocular pressure is positively associated with the cognitive demands of simulated military operations. The potential application of this finding is the development of objective tools based on intraocular pressure for the evaluation of the mental state in real-world contexts, permitting to improve soldiers´ safety and performance.

Exploring Neurocognitive Performance Differences in Military Aviation Personnel

INTRODUCTION: Military aeromedical evaluations are common, but specialized neuropsychological norms for aviation personnel are sparse, resulting in a need to rely on norms from the general population. Little has been published regarding aviation subpopulations and how their neuropsychological profiles may differ from general population normative data. This study investigated neuropsychological test results of aeromedical service members to evaluate consistency with general population norms, and to delineate differences between aviation subpopulations.METHODS: Analyses were conducted on demographic variables and test scores of military aviators (N 26) and nonaviator crewmembers (N 36) referred for evaluation due to a clinical problem requiring a waiver for flight status. Performance differences between subsamples were investigated with general linear modeling. Base rates for low scores were described.RESULTS: Mean test scores in both subsamples were 0 to 1 standard deviation (SD) above the general populations means, with the largest discrepancies being found on measures of visuospatial ability (crewmembers) and verbal learning (aviators). Modeling revealed a significant difference between aviators and crewmembers on Trail Making Test Part B, after accounting for education. Aviators produced fewer low scores than crewmembers, even when using education adjusted normative data.DISCUSSION: Results suggest the cognitive profile of aviators is uniquely strong in specific domains, with fewer low scores. The development of aviator-specific norms may enhance sensitivity to cognitive decrements in this population. Future studies might separately assess crewmember roles to further assess cognitive performance standards across specialties.Maltez-Laurienti A, Minniear A, Moore R, McGovern T, Newman P, Brearly T. Exploring neurocognitive performance differences in military aviation personnel. Aerosp Med Hum Perform. 2021; 92(9):702709.

Abnormal interhemispheric functional connectivity in patients with strabismic amblyopia: a resting-state fMRI study using voxel-mirrored homotopic connectivity

Background

Previous studies have demonstrated that strabismus amblyopia can result in markedly brain function alterations. However, the differences in spontaneous brain activities of strabismus amblyopia (SA) patients still remain unclear. Therefore, the current study intended to employthe voxel-mirrored homotopic connectivity (VMHC) method to investigate the intrinsic brain activity changes in SA patients.

Purpose

To investigate the changes in cerebral hemispheric functional connections in patients with SA and their relationship with clinical manifestations using the VMHC method.

Material and methods

In the present study, a total of 17 patients with SA (eight males and nine females) and 17 age- and weight-matched healthy control (HC) groups were enrolled. Based on the VMHC method, all subjects were examined by functional magnetic resonance imaging. The functional interaction between cerebral hemispheres was directly evaluated. The Pearson’s correlation test was used to analyze the clinical features of patients with SA. In addition, their mean VMHC signal values and the receiver operating characteristic curve were used to distinguish patients with SA and HC groups.

Results

Compared with HC group, patients with SA had higher VMHC values in bilateral cingulum ant, caudate, hippocampus, and cerebellum crus 1. Moreover, the VMHC values of some regions were positively correlated with some clinical manifestations. In addition, receiver operating characteristic curves presented higher diagnostic value in these areas.

Conclusion

SA subjects showed abnormal brain interhemispheric functional connectivity in visual pathways, which might give some instructive information for understanding the neurological mechanisms of SA patients.

Brain structural plasticity in visual and sensorimotor areas of airline pilots: A voxel-based morphometric study

BACKGROUND AND PURPOSE

Airline pilot is a highly specialized profession that requires to response quickly and accurately in the presence of a wide variety of visual information. Although functional imaging studies have employed virtual simulation to identify brain areas that underlie various flying-related tasks, little is known about the specific patterns of structural plasticity in the airline pilot's brain.

MATERIALS AND METHODS

In this study, we examined differences of gray matter and white matter volumes between 42 airline pilots and 39 non-pilots by using voxel-based morphometry, and further assessed the association between magnitude of structural alterations and flight time in the pilots.

RESULTS

We found significantly increased white matter volume in the cuneus area in the pilot group compared to the non-pilot group (p <  0.05, FWE corrected). Using a relaxed threshold, it was also observed that the pilots had increased gray matter volume in the lingual gyrus, inferior frontal gyrus, supramarginal gyrus, cuneus, and postcentral gyrus, and increased white matter volume in the postcentral area (p <  0.001, uncorrected). Moreover, the pilots' flight time was positively correlated with gray matter volume in the postcentral gyrus and white matter volume in the cuneus area (p <  0.001, uncorrected).

CONCLUSIONS

The morphological changes in specific visual and sensorimotor areas may provide airline pilots with neural efficiency in the visuo-motor processing related to flight.

Resting-State Functional Connectivity in Mathematical Expertise

To what extent are different levels of expertise reflected in the functional connectivity of the brain? We addressed this question by using resting-state functional magnetic resonance imaging (fMRI) in mathematicians versus non-mathematicians. To this end, we investigated how the two groups of participants differ in the correlation of their spontaneous blood oxygen level-dependent fluctuations across the whole brain regions during resting state. Moreover, by using the classification algorithm in machine learning, we investigated whether the resting-state fMRI networks between mathematicians and non-mathematicians were distinguished depending on features of functional connectivity. We showed diverging involvement of the frontal-thalamic-temporal connections for mathematicians and the medial-frontal areas to precuneus and the lateral orbital gyrus to thalamus connections for non-mathematicians. Moreover, mathematicians who had higher scores in mathematical knowledge showed a weaker connection strength between the left and right caudate nucleus, demonstrating the connections' characteristics related to mathematical expertise. Separate functional networks between the two groups were validated with a maximum classification accuracy of 91.19% using the distinct resting-state fMRI-based functional connectivity features. We suggest the advantageous role of preconfigured resting-state functional connectivity, as well as the neural efficiency for experts' successful performance.

Altered Default Mode Network Dynamics in Civil Aviation Pilots

Background

Airlines occupy an increasingly important place in the economy of many countries. Because air disasters may cause substantial losses, comprehensive surveys of the psychophysiological mechanism of flying are needed; however, relatively few studies have focused on pilots. The default mode network (DMN) is an important intrinsic connectivity network involved in a range of functions related to flying. This study aimed to examine functional properties of the DMN in pilots.

Method

Resting-state functional magnetic resonance imaging data from 26 pilots and 24 controls were collected. Independent component analysis, a data-driven approach, was combined with functional connectivity analysis to investigate functional properties of the DMN in pilots.

Results

The pilot group exhibited increased functional integration in the precuneus/posterior cingulate cortex (PCC) and left middle occipital gyrus. Subsequent functional connectivity analysis identified enhanced functional connection between the precuneus/PCC and medial superior frontal gyrus.

Conclusion

The pilot group exhibited increased functional connections within the DMN. These findings highlight the importance of the DMN in the neurophysiological mechanism of flying.

Maintenance, reserve and compensation: the cognitive neuroscience of healthy ageing

Cognitive ageing research examines the cognitive abilities that are preserved and/or those that decline with advanced age. There is great individual variability in cognitive ageing trajectories. Some older adults show little decline in cognitive ability compared with young adults and are thus termed 'optimally ageing'. By contrast, others exhibit substantial cognitive decline and may develop dementia. Human neuroimaging research has led to a number of important advances in our understanding of the neural mechanisms underlying these two outcomes. However, interpreting the age-related changes and differences in brain structure, activation and functional connectivity that this research reveals is an ongoing challenge. Ambiguous terminology is a major source of difficulty in this venture. Three terms in particular - compensation, maintenance and reserve - have been used in a number of different ways, and researchers continue to disagree about the kinds of evidence or patterns of results that are required to interpret findings related to these concepts. As such inconsistencies can impede progress in both theoretical and empirical research, here, we aim to clarify and propose consensual definitions of these terms.

Disruption in neural phase synchrony is related to identification of inattentional deafness in real-world setting

Individuals often have reduced ability to hear alarms in real world situations (e.g., anesthesia monitoring, flying airplanes) when attention is focused on another task, sometimes with devastating consequences. This phenomenon is called inattentional deafness and usually occurs under critical high workload conditions. It is difficult to simulate the critical nature of these tasks in the laboratory. In this study, dry electroencephalography is used to investigate inattentional deafness in real flight while piloting an airplane. The pilots participating in the experiment responded to audio alarms while experiencing critical high workload situations. It was found that missed relative to detected alarms were marked by reduced stimulus evoked phase synchrony in theta and alpha frequencies (6-14 Hz) from 120 to 230 ms poststimulus onset. Correlation of alarm detection performance with intertrial coherence measures of neural phase synchrony showed different frequency and time ranges for detected and missed alarms. These results are consistent with selective attentional processes actively disrupting oscillatory coherence in sensory networks not involved with the primary task (piloting in this case) under critical high load conditions. This hypothesis is corroborated by analyses of flight parameters showing greater maneuvering associated with difficult phases of flight occurring during missed alarms. Our results suggest modulation of neural oscillation is a general mechanism of attention utilizing enhancement of phase synchrony to sharpen alarm perception during successful divided attention, and disruption of phase synchrony in brain networks when attentional demands of the primary task are great, such as in the case of inattentional deafness.

Neural signature of inattentional deafness

Inattentional deafness is the failure to hear otherwise audible sounds (usually alarms) that may occur under high workload conditions. One potential cause for its occurrence could be an attentional bottleneck that occurs when task demands are high, resulting in lack of resources for processing of additional tasks. In this fMRI experiment, we explore the brain regions active during the occurrence of inattentional deafness using a difficult perceptual-motor task in which the participants fly through a simulated Red Bull air race course and at the same time push a button on the joystick to the presence of audio alarms. Participants were instructed to focus on the difficult piloting task and to press the button on the joystick quickly when they noticed an audio alarm. The fMRI results revealed that audio misses relative to hits had significantly greater activity in the right inferior frontal gyrus IFG and the superior medial frontal cortex. Consistent with an attentional bottleneck, activity in these regions was also present for poor flying performance (contrast of gates missed versus gates passed for the flying task). A psychophysiological interaction analysis from the IFG identified reduced effective connectivity to auditory processing regions in the right superior temporal gyrus for missed audio alarms relative to audio alarms that were heard. This study identifies a neural signature of inattentional deafness in an ecologically valid situation by directly measuring differences in brain activity and effective connectivity between audio alarms that were not heard compared to those that were heard. Hum Brain Mapp 38:5440-5455, 2017. © 2017 Wiley Periodicals, Inc.