Hans Flohr (doctor)

Hans Werner Flohr (born February 22, 1936 in Bonn ) is a German neurobiologist who is best known for his theory of consciousness and a theory of anesthesia based on it.

biography

Flohr studied medicine and psychology , passed his state examination in 1962 and received his doctorate in 1964 (on lipid-containing proteins of the cerebrospinal fluid). In 1969 he completed his habilitation in physiology . In 1971 Flohr became Professor of Physiology at the University of Bonn, and since 1975 he has been Professor of Neurobiology at the University of Bremen . In 1989/90 he was a fellow at the Center for Interdisciplinary Research , Bielefeld and a member of the “Mind and Brain” research group.

Research priorities

1. Neurobiological foundations of learning and memory ; especially compensation processes after lesions of the nervous system.
2. Neuropharmacology of plastic processes.
3. Physiological conditions of consciousness. Anesthesia. How hallucinogenic substances work.
4. Philosophy of mind .

Theory of Consciousness

In his 1989 essay “ Brain processes and phenomenal consciousness. A new and specific hypothesis ”, Flohr takes the view that states of consciousness can be traced back to specific brain states. The main assumptions of this theory are:

1. States of consciousness are identical to higher-order self-referential representations ( meta-representations ), through which the brain represents its own current state. The phenomenal content of states of consciousness corresponds to the content of these meta-representations.
2. Meta-representations are realized in the brain through the spatiotemporal activity pattern of large, complexly structured neural assemblies.
3. The NMDA synapses of the cerebral cortex are of decisive importance for the formation of such assemblies . Due to their special plastic properties, these synapses implement the binding mechanism that leads to the formation of those assemblies that embody meta-representations.
4. The formation of such assemblies depends on the degree of activation of the cortical NMDA synapses. This determines the speed with which representational structures are built. Meta-representations arise automatically when the cortical NMDA synapses are ubiquitously activated. If the critical degree of activation of the cortical NMDA synapses is not reached, focal disturbances of consciousness or a global loss of consciousness result.

Anesthesia. Hallucinogenic substances

Flohr's theory can be tested empirically. A large number of experimental findings are now known that confirm the predictions that can be derived from them. The theory has great problem-solving potential, ie it provides explanations for facts that have not yet been understood (such as the disturbances of consciousness observed in the autoimmune disease anti-NMDA receptor encephalitis, which was discovered in 2007). In 1995, Flohr developed a theory of anesthesia based on these approaches. This comprises two hypotheses

1. The loss of consciousness characteristic of the anesthetic state is based on a ubiquitous disconnection of the cortical NMDA synapses.
2. All NMDA antagonists (such as ketamine ) are anesthetically effective. Anesthetically active substances that primarily do not attack the NMDA synapse but rather other components of the nervous system (such as GABA _A agonists) lead to a loss of consciousness because they have an indirect inhibitory effect on the NMDA synapse.

For such indirect effects it is essential that the degree of activation of the NMDA synapse depends on two factors: first, the depolarization of the postsynaptic membrane in which the receptor is embedded and, second, the phosphorylation of the receptor protein, which can be influenced by numerous intracellular signal transduction pathways. The effect of hallucinogenic substances (such as LSD , mescaline , amphetamine , scopolamine ) is based - according to Flohr - on a partial inhibition of the cortical NMDA synapses. This results in abnormally structured assemblies and corresponding meta representations with abnormal content. All substances that have a direct inhibitory effect on the NMDA synapse (such as phencyclidine) have a hallucinogenic effect. Substances that primarily attack other central nervous synapses of the central nervous system have this effect because they have an indirect inhibitory effect on the NMDA synapse.

Philosophically speaking, Flohr advocates a representationalist theory of consciousness. His hypotheses correspond to a physicalistic (“mental entities are physical entities”) and reductionistic (“mental states can be traced back to brain processes”).

Publications

Books

1. Flohr, H., Precht, W. (eds.) Lesion-induced plasticity in sensorimotor systems. Springer, Berlin 1981
2. Flohr, H. (ed.) Post-lesion neural plasticity. Springer, Berlin 1988
3. Basar, E., Flohr, H., Haken, H. , Mandell, AJ (eds.) Synergetics of the brain. Springer, Berlin 1983
4. Beckermann, A. , Flohr, H., Kim, J. (eds.) Emergence or Reduction. Essays on the prospects of non-reductive physicalism. De Gruyter, Berlin 1992

Essays

1. Flohr, H., Lüneburg, U. Influence of melanocortin fragments on vestibular compensation. In: Lacour, M., Toupet, M., Denise, P., Christen, Y. Vestibular compensation. Elsevier, Amsterdam 1989
2. Flohr, H., Lüneburg, U. Role of NMDA-receptors in lesion-induced plasticity. Arch.Ital.Biol. 131: 173-190 (1993)
3. Flohr, H. Brain processes and phenomenal consciousness: a new and specific hypothesis. Theory and Psychology 1, 245-262 (1991)
4. Flohr, H. An information processing theory of anesthesia. Neuropsychologia 33, 1169-1180 (1995)
5. Flohr, H. The Physiological Foundations of Consciousness. In: Elbert, T., Birbaumer, N. (eds.) Encyclopedia of Psychology. Biological Foundations of Psychology Vol. 6, Hogrefe, Göttingen 2002
6. Flohr, H. The room of reasons. Double room Phil 53, 5, 1-12 (2005)
7. Flohr, H. Unconsciousness. Best Pract. Res. Clin. Anaesth. 20, 11-22 (2006)

literature

• Otto J. Groeg: Who's who in Germany, Volume 1, Issue 7, Who's who, 1980 ISBN 3921220289

Web links

• Literature by and about Hans Flohr in the catalog of the German National Library
• Hans Flohr's website

Individual evidence

1. ↑ Archived copy ( memento of the original from January 31, 2016 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.