Research Article

A Computationally Efficient, Exploratory Approach to Brain Connectivity Incorporating False Discovery Rate Control, A Priori Knowledge, and Group Inference

Algorithm 1

The algorithm.
Input:  the data , the undirected edges that are assumed to exist in the true undirected graph
according to prior knowledge, the undirected edges ( ) to be tested from the data ,
and the FDR level for making inference about .
Output: an undirected graph , that is, the value of when the algorithm stops, or equivalently, ,
the edges in .
Notations:   denotes the multivariate input data. , denote the vertices. , denote the vertex sets.
denotes an undirected edge. denotes vertices adjacent to in graph . denotes the
conditional independence between and given .
(1) Form an undirected graph from .
(2) Initialize the maximum values associated with the edges in as .
(3) Let depth = 0.
(4) repeat
(5) for  each ordered pair of vertices and that and   do
(6)  for  each subset and   do
(7)   Test hypothesis and calculate the value .
(8)   if   ,  then
(9)    Let .
(10)    if  every element of has been assigned a valid value by step 9, then
(11)     Run the FDR procedure, Algorithm 2, with and as the input.
(12)     if  the non-existence of certain edges are accepted, then
(13)      Remove these edges from .
(14)      Update and .
(15)       if   is removed, then
(16)        break the for loop at line 6.
(17)      end if
(18)     end if
(19)     end if
(20)    end if
(21)  end for
(22) end for
(23) Let .
(24) until   for every ordered pair of vertices and that is in .  
A heuristic modification, named the algorithm, at step 14 removes from as well once
is removed from .