What is the purpose of consciousness


Functional context of states of consciousness

Ideally, a distinction is made between two types of information processing in humans, a conscious and an unconscious system. The first system, too explicit or declarativesystem called, works predominantly serially, slowly (ie in the range of seconds and minutes) and "laborious", is limited in its capacity and prone to errors, its information processing is "deep", ie it is geared towards the processing of complex and meaningful content, it is flexible and can accordingly accomplish new or novel achievements. In humans, it is closely tied to the ability to report verbally. The second, unconsciously running system, too implicit, procedural or non-declarativesystem, called, is almost unlimited in its capacity, works mostly in parallel, quickly and largely error-free. It is "flat" in its information processing, i.e. it processes information on the basis of simple features or meanings and is relatively inflexible or varies within given alternatives. Furthermore, it is not bound to language or is not accessible to a linguistically conscious description. This includes everything that has to do with "implicit learning", with object identification based on external characteristics, training through lengthy practice, unconscious imitation, grouping according to similarities, grasping simple rules. This happens after "flat" information processing below the threshold of meaning acquisition. There are arbitrarily fine transitions between the two systems. The performances and skills from the explicit system usually “sink” with increasing familiarity and practice in the implicit system, but can at least partially be made explicit again with a corresponding effort.

Brain correlates of consciousness

Neurobiology and brain research are able to assign the various states of consciousness and conscious mental performance to the activity of different brain centers. It turns out that there are always many centers involved in the emergence of consciousness, which are distributed over the whole brain. There is no "supreme center of consciousness". We can only become aware of events if they are affected by the activity of the so-called associative cerebral cortex are accompanied, i.e. the posterior and lower parietal lobes (parietal cortex), the middle and lower temporal lobes (temporal cortex) and the frontal lobe (frontal lobe). All that Not takes place in the associative cerebral cortex, we are not aware of it. The sensation of pain ("thalamic pain") may be an exception. The rear and lower Parietal lobes has to do on the left with symbolic-analytical information processing, with mathematics, language and the meaning of drawings and symbols; the right-sided parietal lobe is concerned with real and imagined spatial orientation, with spatial attention and the change of perspective. Our body scheme and the location of our body in space are also localized in the parietal lobe; he also contributes to the planning and preparation of movements. The top and middle Temporal lobe comprises complex auditory perception (auditory system) including the (mostly left-wing) Wernicke language center (language centers), which is important for grasping the meaning of words and languages ​​and for producing meaningful written or spoken language. The lower temporal lobe (IT) is important for complex visual information processing of a non-spatial nature, the grasping of the meaning and correct interpretation of objects, faces etc. as well as of entire scenes. The upper, dorsolateral part of the prefrontal cortex (PFC) is primarily geared towards events in the outside world, especially with regard to their chronological order and their relevance. The working memory is also located there (see above). The lower, orbitofrontal PFC, on the other hand, has to do with social behavior, ethical considerations, divergent thinking, risk assessment, assessment of the consequences of one's own behavior, emotional life and emotional control of behavior.
The cingulate gyrus on the inside of the cerebral cortex plays an important role in attention and other cognitive states accompanied by consciousness such as error correction and decision-making, but also in the sensation of pain (pain). It is a link between the rest of the cerebral cortex and the subcortical centers involved in the development of consciousness in the endbrain itself (especially the hippocampus and amygdala), in the diencephalon (diencephalon; intralaminar nuclei, nucleus reticularis thalami) and in the brain stem (formatio reticularis, ventral tegmental area Area). Although essential for the emergence of consciousness, the activities of these centers are fundamentally incapable of consciousness (with the possible exception of thalamic nuclei for pain sensations).
Those that extend from the extended marrow over the bridge to the anterior midbrain (mesencephalon) Formatio reticularis controls breathing and blood circulation, sleeping and waking, as well as awareness and attention. Even small injuries lead to deep unconsciousness. It is divided into three longitudinal rows of compact cell groups (nuclei). Cores of the medial core group form the ascending activating system. Via switching points in the thalamus (intralaminar nuclei), they increase the general state of excitement of the cerebral cortex and thus our state of wakefulness. The median core group contains the serotonergic dorsal raphe nucleus with connections to the amygdala, the hippocampus and the associative areas of the cerebral cortex. The noradrenergic is located in the lateral core group Locus coeruleus. It has the same connections with areas of the diencephalon and the endbrain as the dorsal raphe nucleus. It is assumed that the dorsal raphe nucleus and the locus coeruleus control the general activation activity of the medial nucleus group. This plays an important role in the control of attention awareness, short-term memory and the understanding of meaningful events basalForebrain (especially the nucleus basalis Meynert). With its cholinergic projection fibers, it is able to specifically strengthen or weaken the activity of delimited regions of the cerebral cortex. The basal forebrain is closely related to the reticular formation and to limbic centers such as the hippocampus and amygdala. Some writers write that Reticular thalami nucleus also plays an important role in controlling attention.
The Hippocampal formation (Ammon's horn, subiculum, dentate gyrus, entorhinal cortex) lies on the inside of the temporal lobe and is used as the organizer of the knowledge memory (declarative memory) viewed, the contents of which are stored in the cerebral cortex, in different places depending on the type and content of memory. Apparently the hippocampal formation determines Where in the cerebral cortex What in which context is saved during learning. However, it is not itself the place of memory and is also not required when "calling up" knowledge that is well memorized. Skills, i.e. the content of the procedural memoryOnce mastered, they are not affected by destruction of the hippocampus. Apparently these are located in the motor cortex or subcortical in the basal nuclei (corpus striatum, pallidum), the bridge (pons) and in the cerebellum.
The storage and conscious retrieval of memory contents depend essentially on accompanying emotional circumstances. Everything we experience and do is assessed in terms of "positive" and "negative". The amygdala on the inner side of the temporal lobe is the organizer or the location of primarily negative evaluations, the nucleus accumbens as part of the basal nuclei and the ventral tegmental area of ​​the midbrain are the organizers of the positive evaluations; both form essential parts of the "emotional memory". When events are made conscious, the contents of this emotional memory are also called up and we experience them as feelings (emotions).
Consciousness is linked on the one hand to an adequate supply of the cerebral cortex with oxygen and sugar (glucose) and on the other hand to a sufficiently strong activation of neurons in the associative cortex. During the states of consciousness restructuring of already existing cortical neural networks apparently takes place - probably through anatomical or functional changes in the synaptic connection structure, or networks are temporarily connected in a new way (possibly under the control of working memory) or permanently. Such processes are very metabolically intensive and lead to an above-average consumption of glucose and oxygen, which in turn increases the local cortical blood flow. This is used in imaging procedures such as positron emission tomography (PET) or functional nuclear magnetic resonance tomography (fMRI). It is still unclear whether certain types of synapses (e.g. NMDA synapses) play a decisive role in the formation of cortical networks.