**2. Stress**

#### **2.1. Neuroendocrine response**

The term "stress" was coined by Hans Selye in 1936 and is defined as a non-specific response of the organism in the presence of any demand imposed. It is produced by the alteration of the cellular homeostasis, with physiological and psychological consequences in the body [1]. At molecular level, stressors can generate the activation of oxidative stress, which is explained by the imbalance of reactive oxygen species such as O2, O2 − , OH<sup>−</sup> , H2 O2 , and the antioxidant molecules (vitamin C, E, flavonoids) [4]. Stress at cellular level is always present to facilitate the processes of cell proliferation, maintenance, and death [5].

At behavioral level, it is recognized that stressors are a threat to which the body requires adaptive adjustments that will allow it to maintain homeostasis and ensure the survival based on experience, biological predisposition, and the status of the organism [6]. During stress, three phases have been distinguished: (1) alarm, (2) resistance, and (3) exhaustion phase. In the alarm phase, the initial reaction of the body to a stimulus generating stress, which restores homeostasis; in this phase, the stressor promotes the stimulation of hypothalamus to secrete ACTH-releasing hormone (CRH). In the resistance phase, prolonged exposure to the stressor leads the exit of the stressful condition or adaptation. During the exhaustion phase, the gradual reduction of the stress response leads to the gradual loss of adaptive capacities [7].

The physical and psychological stressors can trigger the activation of neuronal circuits and peripheral process, for example the inflammation. Cytokines produced by the cells of the immune system can exercise their anti- or pro-inflammatory effect on the cells of the CNS and peripheral organs [8]. The IL-1, IL-6, and IL-17 act on the HPA axis by increasing the secretion of ACTH and cortisol [9]. The TNF-alpha has the ability to destroy certain cell lines and initiates the cascade of proinflammatory cytokines [10]. The regulatory suppressive function of the immune response will depend on the balance of the synthesis of cytokines. If the inflammation is prolonged, other systems will also be activated such as the endocrine system and neurotransmission systems (e.g. noradrenergic, serotonergic, and dopaminergic) [11] (**Figure 1**).

the design of plans and programs, the initiation of the activities and the mental operations, self-regulation, and task monitoring. The prefrontal cortex acts as a controller of executive functions. The executive functions, which help us to organize thoughts, tend to be interrupted

The study of the determinants of academic performance has attracted a remarkable interest in the last few years, given the need to investigate new variables that explain frequent school failure and discouragement in students. Predicting the effect of executive functions on academic performance is important for adequate adaptation of the individual to the specific requirements of the school context. The association between chronic or acute stress and academic performance might be mediated by the effects of cortisol in the prefrontal cortex, which promotes impairment in cognitive functions. Prolonged exposure to stress during different stages of development interferes with both academic achievement and executive functions

Several studies conducted both in animal and human models indicate that factors, such as physical activity, sleep, and a healthy diet, promote optimal cognitive functioning and better academic performance. In this chapter, we discuss both the impact of psychosocial and physiological stressors on executive functions associated with academic performance and some strategies that reduce the impact of stressors. This manuscript compiles a comprehensive review of articles and books indexed in PubMed, SciELO, Scopus, and Google

The term "stress" was coined by Hans Selye in 1936 and is defined as a non-specific response of the organism in the presence of any demand imposed. It is produced by the alteration of the cellular homeostasis, with physiological and psychological consequences in the body [1]. At molecular level, stressors can generate the activation of oxidative stress, which is explained

molecules (vitamin C, E, flavonoids) [4]. Stress at cellular level is always present to facilitate

At behavioral level, it is recognized that stressors are a threat to which the body requires adaptive adjustments that will allow it to maintain homeostasis and ensure the survival based on experience, biological predisposition, and the status of the organism [6]. During stress, three phases have been distinguished: (1) alarm, (2) resistance, and (3) exhaustion phase. In the alarm phase, the initial reaction of the body to a stimulus generating stress, which restores homeostasis; in this phase, the stressor promotes the stimulation of hypothalamus to secrete ACTH-releasing hormone (CRH). In the resistance phase, prolonged exposure to the stressor leads the exit of the stressful condition or adaptation. During the exhaustion phase, the gradual reduction of the stress response leads to the gradual loss of adaptive capacities [7].

− , OH<sup>−</sup> , H2 O2

, and the antioxidant

when the stressors load is too high [1].

12 Health and Academic Achievement

that provide a basis for learning [2, 3].

Advanced Scholar.

**2.1. Neuroendocrine response**

by the imbalance of reactive oxygen species such as O2, O2

the processes of cell proliferation, maintenance, and death [5].

**2. Stress**

**Figure 1.** Neuroendocrine response to stressors. Stressors (physical, chemical, or psychological) lead to the activation of components of the endocrine system, brain, and systemic inflammatory processes. (1) Neural activation and neuroinflammation, (2) peripheral release of modulators of stress, and (3) inflammatory peripheral process. (a) ACTH release, (b) ACTH inhibitory pathway, (c) production of cortisol, and (d) cortisol inhibitory pathway.

amygdala provides an important point of regulation. In the presence of stressful conditions, the prefrontal cortex becomes highly sensitive to damage due to the catecholaminergic nature of its innervating afferents. (2) The critical point of regulation of the amygdala to the prefrontal cortex is characterized by the promotion of the release of noradrenaline and dopamine, which will act at the level of different receptors (D1, D2, A1, β1), activation of hydrogen, calcium, and nitrogen bombs (HCN channels), and even as triggers of the release of neurotrophic factors such as BDNF and GDNF (**Figure 2**). In addition, the endocannabinoid-mediated pathway

Stress and Cognition: Psychological Basis and Support Resources

http://dx.doi.org/10.5772/intechopen.72566

15

Human studies have revealed that the "self-control of stress" can promote reduction of the action of the amygdala, and the subject can solve the stressful situation. An opposite situation will lead deleterious effect on mental and physical health. It has been determined that the absence of control of stress can promote the acquisition of addictive behaviors. During adolescence, addiction to nicotine [16], or even to the internet [17], causes cortical alterations due to decreased mesolimbic dopaminergic function [18]. Limited studies that have focused on this topic have opened a new line of study. Interestingly, the incidence of stressors can promote the establishment of three levels of response to stress in humans: (1) mesencephalic nuclei, (2) cellular response, and (3) systemic (immune-endocrine) [19]. This leads us to infer that: a lack of control strategies can promote alterations at these three levels, increasing the levels of cortisol in the blood, which has an impact on the psychomotor integrity of the individual. At present, diverse activities are being suggested to manage the impact of academic stressors,

Executive functions are a set of cognitive skills that allow for anticipation and establishment of goals, the design of plans and programs, the initiation of activities and mental operations, self-regulation, task monitoring, the precise selection of behavioral, flexibility for cognitive tasks, and organization in time and space. On the other hand, various authors have defined cognitive control as an "executive control" which refers to a set of higher order processes that modulate the interactions of the environmental context of the subject [22, 23]. These functions aim to optimize the selection, management, and coordination that underlie aspects such as

According to Diamond [25], the key executive functions are inhibitory control, working memory, and cognitive flexibility. Other functions, such as reasoning, planning, and organization, would be built from the three main functions. Other authors have defined the executive functions using warm and cold. Warm executive functions are cognitive/emotional processes related to decision-making, motivation, and social cognition. Cold executive functions are related to the rational/cognitive process of high order skills that are used when emotions are

Executive functions can be assessed using neuropsychological tests and are dependent on the prefrontal cortex. The frontal lobes plan, regulate, and control human behavior. This control

also acts as a regulator of stress and emotions [15].

**3. Executive functions**

not an important factor [26].

perception, memory, and execution [24].

such as arts-based activities [20] or controlled physical activities [21].

**Figure 2.** Overview of cellular process associated with executive functions.

Studies in humans and in experimental animals have shown that psychological stressor can suppress or increase the immune response, depending on the length of the stress (acute or chronic). Both in acute and chronic stress, physical exercise induces increase in the production of IL6, IL-4, IL-10, IL-13, IL-17, and TNFα [12]. However, few studies have explored the variation of cytokines in individuals with physical activity; in the case of the IL-17, it has been determined that their serum levels are not altered by the effect of practicing vigorous physical activity (chronic stress) [13]. The real impact of stressor is associated with intensity and frequency.

#### **2.2. Stress and cerebral cortex**

The prefrontal cortex allows efficient connectivity between the circuits associated with emotions, memory, and planning. An example of this is the intricate relationship with neurons of the *locus coeruleus*, *substantia nigra pars compacta,* and ventral tegmental area, by neuromodulators such as norepinephrine and dopamine. Despite to neuroanatomical location and catecholaminergic nature of its afferents, the prefrontal cortex is highly sensitive to damage; for example, during acute stress in rats, the neurites change shape and length over several weeks post damage [7, 14]. In preclinical studies in rats, two sensors and/or regulators of stress associated with the prefrontal cortex have been identified. (1) The direct connection with the amygdala provides an important point of regulation. In the presence of stressful conditions, the prefrontal cortex becomes highly sensitive to damage due to the catecholaminergic nature of its innervating afferents. (2) The critical point of regulation of the amygdala to the prefrontal cortex is characterized by the promotion of the release of noradrenaline and dopamine, which will act at the level of different receptors (D1, D2, A1, β1), activation of hydrogen, calcium, and nitrogen bombs (HCN channels), and even as triggers of the release of neurotrophic factors such as BDNF and GDNF (**Figure 2**). In addition, the endocannabinoid-mediated pathway also acts as a regulator of stress and emotions [15].

Human studies have revealed that the "self-control of stress" can promote reduction of the action of the amygdala, and the subject can solve the stressful situation. An opposite situation will lead deleterious effect on mental and physical health. It has been determined that the absence of control of stress can promote the acquisition of addictive behaviors. During adolescence, addiction to nicotine [16], or even to the internet [17], causes cortical alterations due to decreased mesolimbic dopaminergic function [18]. Limited studies that have focused on this topic have opened a new line of study. Interestingly, the incidence of stressors can promote the establishment of three levels of response to stress in humans: (1) mesencephalic nuclei, (2) cellular response, and (3) systemic (immune-endocrine) [19]. This leads us to infer that: a lack of control strategies can promote alterations at these three levels, increasing the levels of cortisol in the blood, which has an impact on the psychomotor integrity of the individual. At present, diverse activities are being suggested to manage the impact of academic stressors, such as arts-based activities [20] or controlled physical activities [21].
