In physics, there is a group of theories called string theories. Those are theoretical frameworks in which the point-like particles of particle physics are replaced by one-dimensional objects called strings. One notable feature of string theories is that these theories require extra dimensions of spacetime for their mathematical consistency. In bosonic string theory, spacetime is 26-dimensional, while in superstring theory it is 10-dimensional, and in M-theory it is 11-dimensional. [This passage is based on the Wikipedia page of "String Theory" (https://en.wikipedia.org/wiki/String_theory)]
The similarity of the neuroscientists' finding of the eleven-dimensional geometrical structure of the human brain to M-theory is interesting. However, string theories are presently running into difficulty, and any relationship between this finding and the theory in physics is not certain.