NITRC: Generalized PPI Toolbox: PPI analysis, nothing works :)

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PPI analysis, nothing works :)

Dear all, could you please tell me what am I doing wrong?

clear all

clc

skipNum = [14,26,29,37,40,41,55,56]; %array of the participants, which are not existing or problematic

subjects = [10:10];

rois = {'lOFC'}; %one ROI for now; , 'rTPJ'

% choose correct basepath

basepath = fullfile[BLINDED];

addpath(fullfile(basepath, fullfile('04_PPI', 'PPI', 'PPPIv13')));

subjpath = fullfile(basepath,fullfile('07_MRI_DATA'));

for r = 1:length(rois)

clear roi; roi = char(rois(r));

for i = 1:length(subjects)

A = subjects(i);

if ~ismember(A, skipNum) %if NOT a member

P = [];

id = "MP_0" + subjects(i);

clear P

P.subject = char(id);

% directory of first level spm.mat file

% create a copy just in case

firstlevel_dir = fullfile(subjpath, P.subject, 'first_level');

ppi_firstlevel_dir = fullfile(subjpath, P.subject, 'first_level_PPI');

% copy everything ONLY if the PPI copy does not exist yet

if ~isfolder(ppi_firstlevel_dir)

mkdir(ppi_firstlevel_dir); % create empty folder

fprintf('Created empty first_level_PPI for %s\n', P.subject);

else

fprintf('Using existing first_level_PPI for %s\n', P.subject);

end

P.directory = firstlevel_dir;

P.outdir = ppi_firstlevel_dir; %output directory if you want to store the PPI analysis in a different location than the first-level SPM.mat file.

cd(P.directory);

% --- PPPI PARAMETERS ---

% path to VOI (roi.nii) + roiname

P.VOI = fullfile(basepath,'04_PPI','ROIs', [roi,'.nii']);

P.Region = roi; % roi name without '.nii'

% F-contrast to remove noise from the data before deconvolution

% (will be created)

% preprocessing

P.contrast = 'Omnibus F-test for PPI Analyses';

P.analysis = 'psy'; %stands for psychophysiological interaction

P.extract = 'eig'; % method of roi extraction: default = eigenvariate

% Specifies traditional SPM PPI ('trad') or generalized condition-specific PPI ('cond')

P.method = 'cond';

P.equalroi = 0; % specifies that ROIs must be same size in all subjects, 0 allows roi to be trimmed by first level mask

P.FLmask = 1; % 0 - no mask (no such image), default. 1 = specifies that the ROI should be restricted using the mask.img from the first-level statistics.

% Tasks = name of regressors (= the name you put in first-level

% specification. you only need to specify the conditions that you are interested

% in for your PPI analysis. These conditions should match the names of

% the regressors (or conditions) that you used in your first-level analysis.

% regressors / tasks /

P.Tasks = {'1' 'IMM' 'MOR' 'NEU'}; %1 = tasks in all (this case 2) sessions.

% specify contrasts

P.CompContrasts = 1;

P.Contrasts(1).left = {'IMM'};

P.Contrasts(1).right = {'MOR'};

P.Contrasts(1).STAT = 'T';

P.Contrasts(1).name = 'IMM > MOR';

P.Contrasts(2).left = {'MOR'};

P.Contrasts(2).right = {'IMM'};

P.Contrasts(2).STAT = 'T';

P.Contrasts(2).name = 'IMM < MOR';

% if 'cond' as method:

P.Weights = []; % would have to be entered if traditional SPM PPI (n*3 matrix; n = number of conditions)

P.SPMver = 12;

% --- RUN PPPI ---

try

fprintf('Running full estimation for %s\n', P.subject);

P.Estimate = 1;

PPPI(P);

catch ME

warning('Full estimation failed for %s: %s', P.subject, ME.message);

% continue anyway

end

end

My problem:
The analysis runs but gives me an error

Created empty first_level_PPI for MP_010

Running full estimation for MP_010

Log File: MP_010_PPPI_8_26_2025.log

PPPI Version: 13.1.4-17-2014

Parameters used:

Processing subject: MP_010

VOI file : X:\userdata\ekaterinap85\data\Publikation\Moral_Pletti\Pletti_code\04_PPI\ROIs\lOFC.nii

Output file will be: MP_010_lOFC_session#_cond_PPI_regressors.txt

Valid Contrast