# Connectivity analyzing with Correlation

Hi every body
In analyzing of functional connectivity with correlation method, I saved the output in Excel format.
as we can see the matrix of coefficients is symmetric, what is the difference between positive and negative coefficients in coefficients?
For example, node (1, b) and node (A, 2) in the second image have the value -0.9. node (1 , c) and node (a , 3) have the value +0.89.

Can you give additional information about the type of connectivity (directional or nondirectional) in the correlation method ??

best regards

Indeed correlation is a non-directed connectivity metric, thus the connectivity matrix is symmetric.

Correlation measures the linear relationship between two random variables, and the sign indicates the direction of this linear relationship, not to be confused with directionality.

For further information in connectivity methods, their definition and application you can check:
"A Tutorial Review of Functional Connectivity Analysis Methods and Their Interpretational Pitfalls" (Bastos and Schoffelen 2016).