spin_permutations

Synopsis

Performs a spin test to generate null data for hypothesis testing (source code).

Usage

null_data = spin_permutations(data,spheres,n_rep,varargin);

• data: An n-by-m matrix of data to be randomised (single sphere) or cell array of n-by-m matrices (two spheres).
• spheres: Cell array containing spheres.
• n_rep: The number of permutation to perform.
• null_data: The randomised data.
• varargin: See name-value pairs below.

Description

Spin test as described by (Alexander-Bloch, 2018). Data is either an n-by-m matrix where n is the number of vertices and/or parcels or, when spinning on two spheres, a two-element cell array each containing an n-by-m matrix. Spheres is either a file in a format readable by read_surface, a sphere loaded into memory, or a two-element cell array containing files/spheres corresponding to the respective elements in the data cell array.

Name-Value pairs

• ‘parcellation’: a n-by-1 vector containing the parcellation scheme. If you are performing vertexwise analysis, do not provide this pair.
• ‘surface_algorithm’: program used to generate the spheres. Either ‘FreeSurfer’ (default), or ‘CIVET’. If Freesurfer, rotations are flipped along the x-axis for the second sphere.