What happens in the body when the senses suddenly fade, the ground gives way under the feet and the mind is fogged? Is fainting always dangerous or are there also situations in which unconsciousness protects the brain?
What is consciousness, what is unconsciousness?
If you take all thoughts, feelings, memories and perceptions – that is, the totality of experience – together and combine these mental processes with the knowledge of one’s own “I” (the self-awareness), you get a rough idea of the complex concept of “consciousness”, which seems to distinguish us humans from animals.
However, especially in the last years it is increasingly examined to what extent a consciousness and especially a self-consciousness exists in animals; however, the research on animals, which have a communication system that is very different from ours, turns out to be difficult. For example, they cannot tell us what feelings pain triggers in them and to what extent their self-awareness influences their actions.
States of consciousness: consciousness off?
In medicine, consciousness is tested by using various methods to examine attention, orientation, memory, thought, and action. Thus, different states of consciousness (such as tenacity, vigilance, scanning, relaxation, somnolence, REM sleep, coma) are distinguished, of which tenacity is the state of consciousness with the largest attention span and strongest tension, while coma is an extremely reduced state of consciousness in which only a few defense mechanisms are still functioning.
In unconsciousness, consciousness is switched off – this disturbance can be short- or long-term in nature, it depends on the cause. A short-term unconsciousness is also called fainting – because in this situation we are “without power” over our mental and consequently physical processes. Disturbances of consciousness can be of quantitative or qualitative character. In quantitative disorders of consciousness, consciousness is increasingly reduced – in drowsiness and somnolence, the affected person is increasingly sleepy, but not yet unconscious.
In sopor, precoma, and coma, however, unconsciousness is increasingly so profound that the affected person cannot be awakened even by the strongest pain stimuli. Qualitative disorders of consciousness are delirium and twilight state, in which hallucinations, anxiety, or irritability may occur.
How does unconsciousness develop?
The brain, with its complex neural connections, tolerates little deviation from its normal metabolic state. To keep it more or less constant, cerebral blood flow, cerebral metabolism, and the pressure that exists within our bony skull are embedded in a delicate control system that immediately detects and responds to changes.
When a disturbance occurs in this system, all higher brain functions – which include consciousness with all its facets – are scaled back in favor of vital protective functions and reflexes such as regulation of breathing, heartbeat or ensuring a certain blood sugar level: In this way, the brain delays the time when survival can no longer be ensured and irreparable brain and body damage occurs.
