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STRUCTURE and FUNCTION OF NEURONES IN RELATION TO MENTAL ACTIVITY
Author(s) -
MONNÉ LUDWIK
Publication year - 1949
Publication title -
biological reviews
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.993
H-Index - 165
eISSN - 1469-185X
pISSN - 1464-7931
DOI - 10.1111/j.1469-185x.1949.tb00578.x
Subject(s) - cytoplasm , fibril , stimulation , biology , biophysics , cytoplasmic streaming , microbiology and biotechnology , chemistry , biochemistry , endocrinology
Summary 1. The properties, structural, physiological and colloidal, of the cytoplasm of resting and stimulated neurones differ greatly. Jin this respect resting neurones are similar to mature unfertilized sea‐urchin eggs, which are in a depressed condition, and strongly stimulated neurones resemble fertilized sea‐urchin eggs, which are in a highly stimulated condition. The importance of this comparison for understanding the functioning of neurones is stressed. 2. The ground substance of cytoplasm is a texture of fibrils. These fibrils consist of ribonucleic‐acid‐containing chromidia and ribonucleic‐acid‐free interchromidia, which regularly alternate with one another. The structure of cytoplasm is coarse when the fibrils are agglutinated together. The chromidia, which are intensely stainable with basic dyes, aggregate with each other simultaneously with the agglutination of the cytoplasmic fibrils. The structure of cytoplasm is fine when the fibrils are separated from each other and the chromidia are consequently dispersed. 3. The structure of the cytoplasm coarsens rapidly when resting neurones of warm‐blooded animals are excised. This change does not occur when strongly stimulated neurones are excised. Coarse cytoplasmic structure and the aggregated condition of chromidia are correlated with decrease in the rate of respiration, narcosis, hibernation, sleep, and in general with inhibition of cellular activities. Fine cytoplasmic structure and the dispersed condition of chromidia are the characteristic features of chromatolysis, which occurs upon stimulation. 4. Solidifying (clotting) and liquefying enzyme systems control the properties of cytoplasm. The former enzyme system is responsible for the coarsening of cytoplasmic structure and may be activated by narcotics. Stimulation and chromatolysis are brought about when the latter enzyme system is activated. It is probable that clotting enzymes are activated in case of concussion of the brain, and liquefying enzymes upon recovery. 5. It is suggested that mental activities are depressed when the structure of the cytoplasm of neurones is coarse and that these activities are increased when this structure becomes fine. 6. Synthesis of new specific proteins may be the mechanism underlying memory. The structural changes in cytoplasm associated with thinking are probably due to protein synthesis.