I have found an interesting article on the subject above. See this page. According to this study, the viscoelasticity of hippocampus, which is the part of brain, correlates with the memory skill of human.
In my lecture course of rheology, viscoelasticity is of course one of the important topics, and an explanation of viscoelasticity is that, the materials property showing relaxation of modulus and retardation of viscosity. For some people, relaxation and retardation are not familiar. In such a case, handy examples are helpful. For instance, when we attempt to commemorate a series of random numbers, the memory eventually goes away (see forgetting curve). This phenomena is actually a kind of relaxation. Indeed, a viscoelastic material has a memory of deformation within a certain characteristic time so-called relaxation time.
Nevertheless, in my rheology course, I just have forgetting phenomena as an analogy of viscoelasticity, and I did not mean any physical correlation between them. On the other hand, very interestingly, the new study above exhibits the real physical correlation. I will add this story to my list of rheological fun stories.