Appraisal Model of Psychologic Stress

The appraisal model of psychologic stress6 is illustrated in Figure 2-2. When people encounter an environmental stressor such as competition in sports, or illness or injury, they first test the situation for threat: Is the stressor a threat or a challenge, or is it irrelevant? This evaluation is based on beliefs, past experience, and commitment. Events are appraised as threatening if they violate beliefs, contradict experience, or reduce the ability to carry out a commitment. An ankle sprain is a minor inconvenience to a vacationer and may be ignored, but it can be a severe stressor to an Olympic athlete because of the athlete's commitment to the competition. To reduce or remove the threat, the athlete must adapt with new behavior and evaluate what resources are available to cope with it. An optimistic person interprets such an event as a challenge and will try his or her best to recover from the injury.

Such positive emotions, combined with problem-focused strategy, will occupy the athlete and produce a commitment to therapy and training. The athlete's life may be more stressful because of the need for therapeutic activity and behavioral adaptation, but he or she feels hopeful and in control of the situation. A pessimistic person

Secondary resources Opinions and effectiveness

Secondary resources Opinions and effectiveness

Biologic responses: Autonomic, endocrine and immune system

Figure 2-2 Appraisal model of psychologic stress. This model suggests that the primary appraisals of the threat value of an event and secondary appraisals of the effectiveness of available coping strategies have an effect on physiologic response to the event.

may see the stressor as a huge threat and may have no confidence in being able to manage the situation. Negative emotion makes life stressful, with uncertainty and anxiety. Both positive and negative responses to the event are stressful but generate different kinds of physiologic adjustment and different outcomes in reality. The athlete with positive emotion will benefit by reducing the stress and by feeling more energetic, whereas the one with negative emotion will feel more stressed and exhausted.

The example of the injured athlete shows that problem-focused strategies may be costly in terms of energy and time during the period of the stressful event, but they can lessen the intensity of the stress. Pessimistic strategies initially consume fewer resources but can be more costly in the long term because of a continuing drain of coping resources.

When people encounter any change in their environment, they compare it with memories of previous experiences to evaluate whether the change is a

Primary

beliefs and

commitments

Benign or irrelevant

Benign or irrelevant

Psychologic Behavioral responses: responses: Alter defenses, Alter cognitions, etc. environment, ---etc.

stressor (see Fig. 2-2). If it is a stressor, they appraise its threat value and evaluate the options that are available to reduce or eliminate the stress. To eliminate the stress, they use problem-focused strategies that invest more resources to find solutions. Sometimes people may resort to emotion-focused strategies. For example, if an athlete has an ankle sprain, he or she may decide to take a break from training and competition for a few months to minimize the negative effect of the event.

Psychologic responses to stress begin with sensory intake of environmental information and are followed by cognitive interpretation of the information (Fig. 2-3). Sensory information is relayed to the thalamus, the central way station for most incoming information. The information then is sent for prefrontal-limbic interaction. The limbic system regulates memories, emotions, drives, homeostasis, and olfaction (smell). The limbic system includes

Environmental input

Sensory pathways and association areas

Limbic cortex: Anterior cingulate gyrus and prefrontal cortex

Hippocampus declarative memories

Amygdala emotional memories

Hypothalamus diverse cortical and subcortical structures located mainly in the medial and ventral region of the cerebral hemispheres (Box 2-1 and Fig. 2-4).

The prefrontal-limbic interaction after information intake enables people to understand the nature, meaning, and importance of the event and to evaluate the available coping resources and the emotional characteristics of coping strategies. The thalamus also receives visceral signals and relays them to the amygdala. Furthermore, the prefron-tal-limbic interaction provides the hypothalamus with the results of the appraisals and their associated emotion, which leads to changes in peripheral physiologic status. The hypothalamus combines input from the amygdala and the prefrontal cortex. The output of the hypothalamus and its engagement with the brainstem account for autonomic, endocrine, and musculoskeletal reactions to the challenge of stress.

The amygdala is responsible for forming memories of the emotional connotations of these events. The outputs of the hypothalamus activate physiologic responses to the appraised stress.

Two functional subsystems are incorporated in the brainstem pons and medulla (Fig. 2-5). The first is the central feedback loop subsystem, which serves to regulate the functional state of the entire central nervous system, causing it to switch focus to meet behavioral emergencies or to become quiescent when appropriate. This subsystem, consisting of

Skeletal

Endocrine

Brainstem

motor

outputs

and

autonomic

outputs

Bodily expression of emotions and stress reactions

Figure 2-3 A simplified neurophysiologically based model of the primary process that activates autonomic, endocrine, and motor responses to psychologic stress. The hippocampus is essential for recognizing familiar events and facts (declarative memories). The amygdala is responsible for forming memories of these emotional connotations of these events. The outputs of the hypothalamus activate physiologic responses to the appraised stress.

BOX 2-1

Some Components of the Limbic System

Limbic cortex Parahippocampal gyrus Cingulate gyrus Medial orbitofrontal cortex Temporal pole Anterior insula Hippocampal formation Dental gyrus Hippocampus Amygdala Hypothalamus Thalamus Basal ganglia

Cingulate gyrus

Isthmus of the cingulate gyrus

Cingulate gyrus

Isthmus of the cingulate gyrus

Amygdala Hippocampus

Figure 2-4 The limbic system forms a functional bridge between the cerebral cortex and the input and output structures of the nervous system. It is the basis of autonomic, endocrine, and behavioral responses to homeostatic challenges and events, with implications for survival and reproduction. It also helps that the memories of these events are stored and retrieved.

Amygdala Hippocampus

Parahippocampal gyrus

Figure 2-4 The limbic system forms a functional bridge between the cerebral cortex and the input and output structures of the nervous system. It is the basis of autonomic, endocrine, and behavioral responses to homeostatic challenges and events, with implications for survival and reproduction. It also helps that the memories of these events are stored and retrieved.

Superior frontal Cingulate gyrus gyrus

Cingulate sulcus

Corpus callosum

Septum sulcus Cingulate sulcus pellucidum (marginal branch)

Corpus callosum: Rostrum Genu

Anterior cerebral artery

Hypothalamus Uncus

Occipitotemporal gyrus temporal gyrus

Subparietal sulcus

Corpus callosum (splenium)

Parieto-occipital sulcus

Calcarine sulcus

Cingulate sulcus

Subparietal sulcus

Corpus callosum (splenium)

Corpus callosum: Rostrum Genu

Anterior cerebral artery

Calcarine sulcus

Cerebellum: Primary fissure Vermis Hemisphere

Hypothalamus Uncus

Occipitotemporal gyrus temporal gyrus

Figure 2-5 Sagittal hemisection of a brain, showing subsystems.

Cerebellum: Primary fissure Vermis Hemisphere

Figure 2-5 Sagittal hemisection of a brain, showing subsystems.

the pontine reticular formation and its aminergic nuclei and both ascending and descending pathways, determines the global behavioral state of the person: the long-term sense of well-being or dysphoria. The second subsystem, the brainstem response subsystem, contains the descending pathways that reach muscles and viscera. This subsystem also has feedback loops to and from the viscera and muscles, enabling reflex control over autonomic responses. This is a very important mechanism in dry needling stimulation.

Cortisol and epinephrine are the two primary stress hormones, as mentioned earlier. They act in concert with the peripheral components of acute response to stress and influence the entire central nervous system, eventually determining long-term responsiveness to stress. Figure 2-3 shows three sets of outputs from the hypothalamus that adjust bodily stress responses. The output to the endocrine system engages control over peripheral gland secretions that participate in stress reaction. Cortisol and epinephrine act in concert upon different organs and systems to coordinate widespread peripheral stress response. During stress, the endocrine system uses feedback to regulate the following:

• The short-term secretion of stress hormones themselves

• Gene expression in frontal-limbic areas that modulate long-term stress responsiveness

• The shaping of memories for emotionally significant events, which will then affect the appraisal process in the future5

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