RESUMEN
INTRODUCTION: Cortical dynamics of soldiers were examined during a reactive shooting task under varied task demands to investigate the effects of cognitive load on functional states of soldiers in real-time. METHODS: Task demand factors consisted of task load (single, dual), decision load (no-decision, choice-decision), and target-exposure time (short, long). The Dismounted Infantryman Survivability and Lethality Testbed (DISALT) shooting simulator was programmed to generate the eight shooting scenarios and record weapon aim-point data while EEG was acquired continuously during each scenario. Event-related spectral perturbation (ERSP) was derived from single-trial data time-locked to the onsets of targets and peak amplitude and latency measures were analyzed in theta (4-7 Hz) and upper alpha (11-13 Hz) frequency bands. RESULTS: The results are as follows: 1) a stimulus-evoked ERSP theta peak exhibited higher amplitude in the parietal region for choice- vs. no-decision scenarios and longer latency in the right central and temporal regions for dual- vs. single-task scenarios; and 2) ERSP alpha exhibited a progressive increase following the onset of targets with less of an increase in the left central region for dual- vs. single-task scenarios. DISCUSSION: ERSP theta synchronization reflects stimulus encoding and exhibits increased peak power with more complex decision demands and longer latency with secondary task demands, whereas ERSP alpha synchronization reflects motor preparation and exhibits less of an increase with secondary task demands during reactive target shooting tasks. This research contributes the first study of cortical dynamics of soldiers performing a reactive shooting task and has implications for theories of attention and cognitive workload, human factors engineering, and soldier performance.