2008 MMFT Pilot Study with U.S. Marine Reservists
In 2008, we conducted a pilot study of MMFT with a detachment of 37 U.S. Marine reservists who received MMFT training before they deployed to Iraq. Before and after MMFT, the Marines participated in a battery of behavioral tasks to measure their cognitive capabilities. We measured aspects of attention and working memory capacity, the capacity to maintain attentional control over time. We also measured their perceived stress levels and emotional experience using self-report questionnaires. In addition, we gathered control group data from civilians and from another pre-deployment Marine reservist detachment that did not receive MMFT.
The pilot study results suggest that MMFT may protect against the cognitive declines that often accompany pre-deployment training. The more time Marines engaged in MMFT exercises outside of class, the greater the improvement in their cognitive functioning, the greater the decrease in their levels of perceived stress, the greater the decrease in their negative emotions, and the greater the increase in their positive emotions – despite an objective increase in stressors during the pre-deployment period.
2011 Study with U.S. Marines of the 1st Marine Expeditionary Force
In 2011, we conducted a randomized control trial study with 320 U.S. Marines preparing for deployment to Afghanistan. During their pre-deployment preparations, half of these Marines received MMFT and half did not. Marines were assessed at baseline, 8 weeks later, and then again approximately one week later, during and after a stressful combat training session at the Infantry Immersive Trainer (IIT). The IIT is a training facility at Camp Pendleton, CA, designed to expose infantry units to the sights, sounds, smells, and feeling of combat in a mountain village.
The study measured MMFT’s effects with brain imaging (fMRI), blood and saliva biomarkers, cognitive tests, self-report measures, and heart-rate and breathing-rate during the combat training drills at the IIT.
The results suggest that the mechanisms related to stress recovery can be modified in healthy individuals prior to stress exposure, leading to more effective performance during and after stressful events. In addition, the results reinforced the pilot study finding that MMFT may protect against the cognitive declines associated with pre-deployment training.
In this study, compared to the control group, the Marines who received MMFT showed a more potent response to stress during combat drills (measured by heart-rate) followed by a quicker and enhanced recovery (measured by heart- and breathing-rate) after combat drills at the IIT. The MMFT Marines also showed lower blood-plasma neuropeptide Y concentrations after the combat drills. Neuropeptide Y is a key biomarker of resilience in the scientific literature. Lower neuropeptide Y levels suggest the MMFT Marines were more efficient at self-regulation, with a quicker return to baseline following stress.
In the fMRI findings, MMFT Marines showed an attenuated blood-oxygen-level-dependent signal in the right insula and anterior cingulate. These are brain regions implicated in self-regulation, emotion regulation, and impulse control. These results suggest MMFT may directly modulate interoceptive function towards more efficient processing of cues signaling perturbation of homeostasis, which facilitates more effective self-regulation and recovery from stress. These results also suggest that after receiving MMFT, Marines did not need to expend as much cognitive effort to down-regulate negative emotions and control impulsive actions. These shifts in MMFT Marines’ brain activation patterns are similar to those observed in “elite performers” (in both military and civilian samples) relative to healthy adults, in previous studies by this research team. For more information about the results of our research, please see our publications which explain the empirical findings in more detail.