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. 1992 Aug 15;89(16):7320–7324. doi: 10.1073/pnas.89.16.7320

Evolution of consciousness.

J C Eccles 1
PMCID: PMC49701  PMID: 1502142

Abstract

The hypothesis of the origin of consciousness is built upon the unique properties of the mammalian neocortex. The apical dendrites of the pyramidal cells bundle together as they ascend to lamina I to form neural receptor units of approximately 100 apical dendrites plus branches receiving hundreds of thousands of excitatory synapses, the collective assemblage being called a dendron. It is proposed that the whole world of consciousness, the mental world, is microgranular, with mental units called psychons, and that in mind-brain interaction one psychon is linked to one dendron through quantum physics. The hypothesis is that in mammalian evolution dendrons evolved for more effective integration of the increased complexity of sensory inputs. These evolved dendrons had the capacity for interacting with psychons that came to exist, so forming the mental world and giving the mammal conscious experiences. In Darwinian evolution, consciousness would have occurred initially some 200 million years ago in relation to the primitive cerebral cortices of evolving mammals. It would give global experiences of a surrounding world for guiding behavior beyond what is given by the unconscious operation of sensory cortical areas per se. So conscious experiences would give mammals evolutionary advantage over the reptiles, which lack a neocortex giving consciousness. The Wulst of the avian brain needs further investigation to discover how it could give birds the consciousness that they seem to have.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Eccles J. C. Do mental events cause neural events analogously to the probability fields of quantum mechanics? Proc R Soc Lond B Biol Sci. 1986 May 22;227(1249):411–428. doi: 10.1098/rspb.1986.0031. [DOI] [PubMed] [Google Scholar]
  2. Eccles J. A unitary hypothesis of mind-brain interaction in the cerebral cortex. Proc R Soc Lond B Biol Sci. 1990 Jun 22;240(1299):433–451. doi: 10.1098/rspb.1990.0047. [DOI] [PubMed] [Google Scholar]
  3. Jack J. J., Redman S. J., Wong K. The components of synaptic potentials evoked in cat spinal motoneurones by impulses in single group Ia afferents. J Physiol. 1981 Dec;321:65–96. doi: 10.1113/jphysiol.1981.sp013972. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Kelly R. B., Deutsch J. W., Carlson S. S., Wagner J. A. Biochemistry of neurotransmitter release. Annu Rev Neurosci. 1979;2:399–446. doi: 10.1146/annurev.ne.02.030179.002151. [DOI] [PubMed] [Google Scholar]
  5. Korn H., Faber D. S. Transmission at a central inhibitory synapse. IV. Quantal structure of synaptic noise. J Neurophysiol. 1990 Jan;63(1):198–222. doi: 10.1152/jn.1990.63.1.198. [DOI] [PubMed] [Google Scholar]
  6. Peters A., Kara D. A. The neuronal composition of area 17 of rat visual cortex. IV. The organization of pyramidal cells. J Comp Neurol. 1987 Jun 22;260(4):573–590. doi: 10.1002/cne.902600410. [DOI] [PubMed] [Google Scholar]
  7. Posner M. I., Petersen S. E., Fox P. T., Raichle M. E. Localization of cognitive operations in the human brain. Science. 1988 Jun 17;240(4859):1627–1631. doi: 10.1126/science.3289116. [DOI] [PubMed] [Google Scholar]
  8. Redman S. Quantal analysis of synaptic potentials in neurons of the central nervous system. Physiol Rev. 1990 Jan;70(1):165–198. doi: 10.1152/physrev.1990.70.1.165. [DOI] [PubMed] [Google Scholar]
  9. Roland P. E., Larsen B., Lassen N. A., Skinhøj E. Supplementary motor area and other cortical areas in organization of voluntary movements in man. J Neurophysiol. 1980 Jan;43(1):118–136. doi: 10.1152/jn.1980.43.1.118. [DOI] [PubMed] [Google Scholar]
  10. Sayer R. J., Redman S. J., Andersen P. Amplitude fluctuations in small EPSPs recorded from CA1 pyramidal cells in the guinea pig hippocampal slice. J Neurosci. 1989 Mar;9(3):840–850. doi: 10.1523/JNEUROSCI.09-03-00840.1989. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Schmolke C., Fleischhauer K. Morphological characteristics of neocortical laminae when studied in tangential semithin sections through the visual cortex of the rabbit. Anat Embryol (Berl) 1984;169(2):125–132. doi: 10.1007/BF00303141. [DOI] [PubMed] [Google Scholar]
  12. Szentágothai J. The Ferrier Lecture, 1977. The neuron network of the cerebral cortex: a functional interpretation. Proc R Soc Lond B Biol Sci. 1978 May 16;201(1144):219–248. doi: 10.1098/rspb.1978.0043. [DOI] [PubMed] [Google Scholar]
  13. Walmsley B., Edwards F. R., Tracey D. J. The probabilistic nature of synaptic transmission at a mammalian excitatory central synapse. J Neurosci. 1987 Apr;7(4):1037–1046. doi: 10.1523/JNEUROSCI.07-04-01037.1987. [DOI] [PMC free article] [PubMed] [Google Scholar]

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