Pilot expertise and hippocampal size: associations with longitudinal flight simulator performance

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.

Brain structure variability study in pilots based on VBM

The impact of occupations on brain structures has attracted considerable research interests in the last decade. The aim of this research is to find the effect of flight training on brain gray matter volume of pilots. The whole-brain structural magnetic resonance imaging (sMRI) data collected from 26 pilots and 24 controls was analyzed using Voxel-based morphological analysis method (VBM) combined with T1 data to quantitatively detect the local gray matter of brain tissue and calculate the gray matter volume. The result shows that the pilot group has larger gray matter volume in the lingual gyrus and fusiform gyrus compared to the control group (P<0.05). Furthermore, there is a positive correlation between the gray matter volume and the number of flight hours (r = 0.426, P = 0.048) after studying the average gray matter volume value of the agglomerate of participants whose flight hours are between 0 and 1000 hours. The lingual gyrus and fusiform gyrus are involved in high-level visual processing, memory, multisensory integration and perception. The study has indicated the flight training could enlarge gray matter volume in the lingual gyrus and fusiform gyrus. During flying, pilots need to observe the instrumentation in the cockpit and fully interpret the readings, which may lead to the results.

Experticia y cognición. Exploración de funciones cognitivas verbales y visoespaciales en arquitectos y psicólogos

Diversas investigaciones han advertido que el ejercicio de algunas profesiones puede conllevar efectos moduladores en la estructura cerebral y el funcionamiento cognitivo. Se presentan los resultados de un estudio exploratorio transversal referente a las modificaciones que las experticias en arquitectura (N = 41, edad: X = 39, DE = 10) y en psicología (N = 40, edad: X = 35, DE = 7) producen sobre procesos cognitivos específicos. El objetivo general fue contribuir a la determinación de perfiles cognitivos diferenciales. Los arquitectos mostraron un mejor rendimiento en tareas que involucran la retención y manipulación de información visoespacial. No se hallaron diferencias significativas en la resolución de tareas verbales. Estos resultados sugieren que la experiencia en arquitectura podría conducir a un desempeño conductual mejorado en procesos cognitivos correspondientes a la memoria de trabajo visoespacial. Se discuten los alcances de la presente exploración y las instancias necesarias para la validación de estas observaciones. Se sugiere la realización de nuevos estudios que integren seguimiento longitudinal y tecnologías de neuroimagen.

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

The most common lethal accidents in General Aviation are caused by improperly executed landing approaches in which a pilot descends below the minimum safe altitude without proper visual references. To understand how expertise might reduce such erroneous decision-making, we examined relevant neural processes in pilots performing a simulated landing approach inside a functional MRI scanner. Pilots (aged 20-66) were asked to "fly" a series of simulated "cockpit view" instrument landing scenarios in an MRI scanner. The scenarios were either high risk (heavy fog-legally unsafe to land) or low risk (medium fog-legally safe to land). Pilots with one of two levels of expertise participated: Moderate Expertise (Instrument Flight Rules pilots, n = 8) or High Expertise (Certified Instrument Flight Instructors or Air-Transport Pilots, n = 12). High Expertise pilots were more accurate than Moderate Expertise pilots in making a "land" versus "do not land" decision (CFII: d' = 3.62 ± 2.52; IFR: d' = 0.98 ± 1.04; p<.01). Brain activity in bilateral caudate nucleus was examined for main effects of expertise during a "land" versus "do not land" decision with the no-decision control condition modeled as baseline. In making landing decisions, High Expertise pilots showed lower activation in the bilateral caudate nucleus (0.97 ± 0.80) compared to Moderate Expertise pilots (1.91 ± 1.16) (p<.05). These findings provide evidence for increased "neural efficiency" in High Expertise pilots relative to Moderate Expertise pilots. During an instrument approach the pilot is engaged in detailed examination of flight instruments while monitoring certain visual references for making landing decisions. The caudate nucleus regulates saccade eye control of gaze, the brain area where the "expertise" effect was observed. These data provide evidence that performing "real world" aviation tasks in an fMRI provide objective data regarding the relative expertise of pilots and brain regions involved in it.

Effects of body mass index-related disorders on cognition: preliminary results

BACKGROUND

Well-known risk factors for cognitive impairment are also associated with obesity. Research has highlighted genetic risk factors for obesity, yet the relationship of those risk factors with cognitive impairment is unknown. The objective of this study was to determine the associations between cognition, hypertension, diabetes, sleep-disordered breathing, and obesity. Genetic risk factors of obesity were also examined.

METHODS

The sample consisted of 369 nondemented individuals aged 50 years or older from four community cohorts. Primary outcome measures included auditory verbal memory, as measured by the Rey Auditory Verbal Learning Test, and executive functioning, as measured by the Color-Word Interference Test of the Delis-Kaplan Executive Function System battery. Apnea-hypopnea index indicators were determined during standard overnight polysomnography. Statistical analyses included Pearson correlations and linear regressions.

RESULTS

Poor executive function and auditory verbal memory were linked to cardiovascular risk factors, but not directly to obesity. Genetic factors appeared to have a small but measureable association to obesity.

CONCLUSION

A direct linkage between obesity and poor executive function and auditory verbal memory is difficult to discern, possibly because nonobese individuals may show cognitive impairment due to insulin resistance and the "metabolic syndrome".