Neural Mechanisms as Putative Targets for Warfighter Resilience and Optimal Performance - Neurotechnology in National Security and Defense - page 57

The prevalent model of performance in sports physiology is the central governor
model, which centers on perceived exertion (Borg and Dahlstrom 1962) (the sub-
jective perception of exercise intensity) and has been used to explain performance
differences in athletes (St. Clair and Noakes 2004). Recently, this model has been
extended by Tucker and colleagues (2009) based on prior formulations by Hampson
et al. (2001). Specifically, a system of simultaneous efferent feedforward and afferent
feedback signals is thought to optimize performance by overcoming fatigue through
permitting continuous compensation for unexpected peripheral events (Hampson
et al. 2001). Afferent information from various physiological systems and external
or environmental cues at the onset of exercise can be used to forecast the duration
of exercise within homeostatic regulatory limits. This enables individuals to termi-
nate the exercise when the maximum tolerable perceived exertion is attained. In this
model, the brain creates a dynamic representation of an expected exertion against
which the experienced exertion can be continuously compared (Tucker 2009) to pre-
vent exertion from exceeding acceptable levels. The notion of a differential between
expected and experienced exertion parallels our model of the body prediction error
(Paulus et al. 2009). However, the degree to which peripheral input is necessary is
still under debate. For example, Marcora and colleagues (2009) have developed a
psychobiological model which proposes that perceived exertion is generated by a
top-down or feedforward signal (Marcora 2008), that is, the brain—not the body—
generates the sense of exertion. These investigators have argued that a centrally gen-
erated corollary discharge of the brain is critical for optimal effort (Marcora 2010)
and that mental fatigue affects performance via altered perception of effort rather
than afferent and body originating cardiorespiratory and musculoenergetic mecha-
nisms (Marcora et al. 2009). Nevertheless, whether it is a purely central process, as
suggested by Marcora (2008), or an interaction between afferent peripheral feedback
and efferent central feedforward systems, the differential between the expected and
observed, that is, the body prediction error, is the critical variable that moderates
performance. The implementation of this process in the brain and its modulation by
nature or nurture will be central to understand optimal performance.
REFRAMING RESILIENCE
Resilient individuals are able to generate positive emotions to help them cope with
extreme situations (Tugade et al. 2004). According to Tugade and Fredrickson's
(2004) broaden-and-build theory, positive emotions facilitate enduring personal
resources and broaden one's momentary thought of action repertoire. That is, posi-
tive emotions broaden one's awareness and encourage novel, varied, and exploratory
thoughts and actions, which, in turn, build skills and resources. For example, expe-
riencing a pleasant interaction with a person you asked for directions turns, over
time, into a supportive friendship. Furthermore, positive emotions help resilient indi-
viduals to achieve effective coping, serving to moderate stress reactivity and medi-
ate stress recovery (Southwick et al. 2005). We suggest individuals that score high
on self-reported resilience may be more likely to engage the insular cortex when
processing salient information and are able to generate a body prediction error that
enables them to adjust more quickly to different external demand characteristics.