[Viscoelastic property of human brain -for the analysis of impact injury (author's transl)].

1. Viscoelasticity of the human brain was investigated in order to understand the physical properties of the brain and to apply it to the analysis of the head injury mechanisms. 2. Static shear modulus (G) of the human white matter was 2.4 X 10(3) dyne/cm2. 3. Complex Young's modulus (E*(omega) = E' + iE") of the white matter, the gray matter, and the brain stem was measured in the range of 3-36 degrees C and 3-35 Hz using the dynamic viscoelastometer. Storage Young's modulus (E') of both white and gray matters of human brain was in the figures of 10(5) dyne/cm2 and loss Young's modulus (E") of those showed 10(4)-15(5) dyne/cm2. 4. The viscoelasticity of human brain is illustrated in Fig. 4 on the assumption of the equivalence of time and temperature. In case of head injury with impact duration of 5 msec it is proper to use the following value : E' = 4 X 10(5) dyne/cm2, E" = 2 X 10(5) dyne/cm2 in the white matter and E' = 3 X 10(5) dyne/cm 2, in the gray matter. 5. The visoelasticity of gelatin and bean curds were also examined to know whether or not simulation of the brain was possible. The viscoelasticity of 5-15% gelatin with an addition of 5% formalin was decreased 1-2 figures compared with that of the brain. The viscoelasticity of bean curds was about the same as that of the brain.