Page 20 - JSOM Summer 2025

TABLE 2 Interaction and Main Effect Results Based on the Mixed Effects Model Performed on fNIRS-derived Hemodynamic Responses
During the Dynamic Shoot/No-Shoot Marksmanship Task
fNIRS-derived Hemodynamic Responses of the Prefrontal Cortex
HbO 2 , µM Deoxygenated Hb, µM Total Hb, µM
Effect F P value F P value F P value
Group F =5.88 0.017 F =2.97 0.089 F =7.38 0.008
1,87.47 1,88 1,88
Time F =2.67 0.052 F =0.33 0.806 F =1.23 0.305
3,87.01 3,88 3,88
Group x time F 3,87.01 =0.34 0.992 F 3,88 =0.05 0.983 F 3,88 =.03 0.992
fNIRS = functional near-infrared spectroscopy.

FIGURE 2 Functional near-infrared
spectroscopy (fNIRS)-derived
relative concentration values
(mean ± SD) for oxyhemoglobin
(HbO ) [A.], deoxyhemoglobin
2
(deoxygenated Hb) [B.], and total
hemoglobin (total Hb) [C.] captured
from the prefrontal cortex (PFC)
and averaged across five time points
(Q , Q , Q , and Q ).
1 2 3 4
• represents the proficient marksmanship group, and represents the non-proficient marksmanship group.
*Significant main effect for group in which non-proficient > proficient (p<.05).

There was, however, a significant difference in group which HbO ) than moderate and good performers. Likewise, Leff et
22
2
indicated that on average, the non-proficient marksmen had al. and Nemani et al. reported greater HbO responses in the
2
a 42.1% greater total Hb response than the proficient marks- PFC of novice medical students during fine motor skill tasks
men throughout the dynamic marksmanship COF (Figure 2C). (knot tying and pattern cutting) 38,39 than expert practitioners.
Additionally, Mark et al. demonstrated that individuals who
underwent neuroadaptive flight training exhibited reduced
Discussion
cognitive workload (i.e., reduced HbO ) during a dynamic
2
This study investigated the feasibility of using fNIRS to as- flight task relative to novice individuals. Collectively, these
43
sess cognitive load differences between proficient and non- findings reinforce the notion that greater PFC activation in less
proficient marksmen during a dynamic shoot/no-shoot pistol proficient individuals reflects an increased reliance on cognitive
marksmanship task. The results indicated that non-proficient resources, which may contribute to reduced neural flexibility
marksmen exhibited significantly higher levels of PFC ac- and constrained task performance in high-stakes environments
tivation (as indicated by a 26.3% greater HbO and 42.1% or occupational settings. 22,36,38,39,43 In marksmanship, where
2
greater total Hb relative to proficient marksmen), while de- rapid threat discrimination and precision are critical, reduced
oxygenated Hb remained unchanged (Figure 2A–C). Despite PFC activation in more proficient marksmen may indicate a
no significant differences in completion time during the shoot/ greater ability to streamline cognitive processes, thereby miti-
no-shoot pistol marksmanship task (p=.34), the increased PFC gating performance decrements.
activation in the non-proficient group suggests a greater ox-
ygenated blood flow requirement to support neural activity This feasibility study quantified hemodynamic differences in
in the PFC, which may be indicative of heightened cognitive individuals stratified by performance during a marksmanship
effort. 34,35 task and used the outcomes as a physiological indication of
cognitive load. Despite the prominence of HbO being reported
2
These findings align with those of Ortiz and colleagues who in cognitive workload studies, the optimal fNIRS-derived
reported elevated total Hb in the PFC of non-proficient drone marker to represent neural activity between HbO , deoxygen-
2
pilots, linking greater PFC activation to increased cognitive de- ated Hb, or total Hb remains unclear, according to Luke and
mands relative to proficient pilots. Additionally, Ortiz et al. colleagues (preprint). However, HbO has been suggested to
45
36
2
also found that as proficiency increased, there was an inverse be more sensitive to task-related changes than deoxygenated
45
relationship between PFC total Hb and self-confidence in the Hb and shows greater test-retest reliability. Moreover, total
task supporting the neural efficiency hypothesis, where more Hb, which represents the sum of HbO and deoxygenated Hb,
2
proficient individuals optimize cognitive resources more effi- is less susceptible to extracerebral contamination and serves
ciently. Similarly, comparative fNIRS studies across various as a useful proxy measure of cerebral blood flow. 45,46 Given
34
domains including medical simulations, 37–41 aviation, 42,43 and that this is one of the first studies to apply fNIRS to quantify
laboratory-based cognitive tasks 22,44 consistently show that nov- cognitive load during a marksmanship task, we propose that
ices and low performers routinely exhibit greater PFC activation HbO and total Hb are the most sensitive indicators of in-
2
due to increased cognitive load and reduced task automation creased cognitive load during dynamic pistol marksmanship,
in both males and females. 22,23,43 Zohdi and colleagues (2023) with differences in cortical activity based on proficiency lev-
found that individuals classified as low performers during a els aligning with the neural efficiency hypothesis (i.e., reduced
verbal fluency task had greater PFC activation (i.e., elevated PFC activity in more skilled marksmen). 34
18 | JSOM Volume 25, Edition 2 / Summer 2025