Arousal
Arousal is a term from psychology and physiology . It denotes the general degree of activation of the central nervous system in humans and vertebrates . Characteristic features include a. Alertness , alertness and responsiveness.
You have a very low arousal level during sleep, a very high level in pain and similar states of excitement. A high level of arousal can also be found in people who are aroused by anger, fear or sexual desire. However, arousal itself has no emotional component and must therefore be differentiated from “arousal”.
Arousal can be recognized in the laboratory, for example, in the EEG , which is desynchronized , i.e. That is, different frequencies with small excursions occur. Arousal can be measured, one speaks of the level or level of arousal. The electrical voltage measured in the EEG and its frequency serve as a measure.
Neurobiology
"Arousal is a general activation of the cortex, triggered by incoming sensory impulses and mediated on the pathways of the reticular formation of the brain stem, with the effect of increased alertness or alertness."
Arousal is triggered by sensory impulses on a certain part of the brain stem ( Formatio reticularis ), by stimulation from the cerebral cortex and by the level of the hormone adrenaline . Arousal influences the entire organism via the reticular formation, i. H. the brain, vegetative nervous system and thus the metabolism .
Arousal and performance
In a state of strong arousals, we are very alert and ready to react and particularly receptive to external stimuli. However, the mental and physical performance is no longer optimal. That is why we cannot absorb knowledge content so well when we are angry, for example. Even athletes do not perform well when they are overly nervous. We know this heightened arousal even when, for example, we give a speech and fall into a state of objective self- awareness - we are excited.
The Yerkes-Dodson law of 1908 shows the relationship between performance and arousal. According to this, difficult tasks can be mastered up to a certain level of arousal. However, as the arousal increases, the performance capacity decreases. However, light tasks can still be mastered well beyond this point. However, there are also limits to this performance. If the state of excitement increases further, even easy tasks can no longer be mastered. Yerkes and Dodson showed
- that there is an optimal level of arousal in which both difficult and easy tasks can still be managed well,
- that a certain level of arousal is necessary to perform at all.
Basically, the highest performance is achieved with a medium arousal level ( Eu stress ). Then there is a drop in performance from fatigue to exhaustion and illness to collapse (so-called distress ).
Medical importance
Sleep apnea syndrome
Sleep apnea syndrome is also referred to as an arousal . Respiratory arrests during sleep, known as apneas, result in an insufficient oxygen content in the blood , known as hypoxemia , while at the same time an increased carbon dioxide content in the blood, known as hypercapnia . The oxygen exchange in the organs, which is no longer possible, is recognized by chemoreceptors and overcome by a wake-up reaction, the arousal. This wake-up reaction does not lead to full consciousness, but it does resume ventilation and thus normalize the blood gases.
In the EEG a sudden frequency change can be seen for several seconds. There is a temporary activation of the organism, increased activity of the autonomic nervous system, increased muscle tone and a lowering of the stimulus threshold.
The high number of arousals typical of this disease impairs sleep, which is no longer restful as a result. This has an even more serious effect on the cardiovascular system ; obstructive sleep apnea syndrome is causal for cardiovascular diseases.
In sleep medicine
In addition to the arousals described in sleep apnea syndrome, a distinction is made between other types of arousals in connection with sleep and its disorders in the sense of wake-up reactions. "External arousals", which are triggered by physical stimuli such as light, vibrations and noise, and "intrinsic arousals", which are triggered by periodic leg movements or gastroesophageal reflux during sleep, affect the restfulness of sleep . In addition, “physiological arousals” occur, which are spontaneous central nervous activations in the physiological process of sleep, which usually do not impair the restfulness of sleep.
In sleep medicine, certain sleep disorders from the group of parasomnias are referred to as "arousal disorders" : sleep intoxication , sleepwalking (somnambulism) and pavor nocturnus (night terror).
See also
literature
- E. Grandjean: Physiological work design . Ott Verlag Thun, 1991, ISBN 3-7225-6651-7 .
- L. Deckers: Motivation - Biological, Psychological, and Environmental . Pearson Boston, 2nd 2005, ISBN 0-205-40455-3 .
Individual evidence
- ↑ American Academy of Sleep Medicine (Ed.): The AASM Manual for Scoring Sleep and Associated Events. Rules, technology and technical specifications . 1st edition. Steinkopff-Verlag, Heidelberg 2008, ISBN 978-3-7985-1851-3 .
- ↑ Boris A. Stuck, Joachim T. Maurer, Michael Schredl , Hans-Günter Weeß: Practice of sleep medicine: sleep disorders in adults and children . Springer, Heidelberg 2009, ISBN 978-3-540-88699-0 , pp. 45 .
- ↑ S3 guideline for non-restful sleep / sleep disorders of the German Society for Sleep Research and Sleep Medicine (DGSM). In: AWMF online (as of 2009).