Brain network representations of placebo analgesia.
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- [1] § Materials and methods › Functional connectivity network mapping ↔ Code/FCNM.m, lines 43–168 · score 0.58 · FC maps, correlation, spheres, mask, radius, thresholded
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The authors' code
MATLAB · 221 lines · 9.4 KB · no license · 1 match
- %%% ---------------------------------------------------------------------------------------------------
- %%% Functional Connectivity Network Mapping (FCNM)
- %%% ---------------------------------------------------------------------------------------------------
- %%% This script manages data from Excel to combined masks, individual-level zFC,
- %%% group-level T-maps, and final group probability maps.
- %%% Developed by ChatGPT and Mofan, Anhui Medical University, December 28, 2022.
- %%% ---------------------------------------------------------------------------------------------------
- %%% Steps:
- %%% 1. Load and set paths.
- %%% 2. Establish directory structure and capture PDF file names for studies.
- %%% 3. Prepare Excel spreadsheets for later ROI generation.
- %%% 4. Generate ROI spheres, process BOLD files, and perform statistical analyses.
- %%% 5. Create and refine group probability maps.
- %%% ---------------------------------------------------------------------------------------------------
- %% Step 1: Add spm12 and ROI_ball_gen_combined.m to the path and clear all variables
- clear, clc
- support_path = 'F:\test\extra'; % Path for support files
- addpath(support_path);
- %% Step 2: Read the basic information and title of each independent study
- % Typically, we have downloaded all the PDFs of included studies, recommended to be named as "P + Number + Author + Year of Publication", e.g., P01Li2017
- % If not all PDFs are downloaded, create a placeholder PDF for missing studies as we only need to read each document's basic information and title
- path = 'F:\test';
- mkdir([path,'\Articles_Included']); % Create a new folder 'Articles_Included' to store all included PDF files of the studies
- Articles_path = [path, '\Articles_Included'];
- File = dir(fullfile(Articles_path, '*.pdf')); % Read all PDF files in 'Articles_Included', representing all studies. The file name without '.pdf' is obtained by (end-4)
- Filename = {File.name};
- %% Step 3: After reading the information, create an Excel spreadsheet for all articles' coordinates, which will be manually filled in later
- mkdir([path, filesep, 'Articles_Included_Excel']); % Create a new folder 'Articles_Included_Excel'
- cd([path, filesep, 'Articles_Included_Excel']); % Enter this folder
- for i = 1:length(Filename) % Create an Excel spreadsheet for each study, where coordinates will be manually entered into the spreadsheet later and saved. If there are multiple ROI results, the spreadsheet can be autofilled downwards
- filename = char(Filename(i));
- xlswrite([filename(1:end-4), '.xlsx'], cellstr([filename(1:end-4), '_ROI01']), 'sheet1', 'D1')
- end
- %% Step 4: Generate spheres for each study's ROI and merge spheres from the same study
- radius_Seeds_results = [path, '\4mm_Seeds_Results\']; % Note to adjust the radius size when generating spheres with different radii, here it is 4mm
- parfor i = 1:length(Filename)
- filename = char(Filename(i));
- article_folder = fullfile(radius_Seeds_results, filename(1:end-4));
- mkdir(article_folder)
- ROI_Seeds_path = fullfile(article_folder, 'ROI_Seeds');
- if ~exist(ROI_Seeds_path, 'dir')
- mkdir(ROI_Seeds_path)
- end
- onesample_path = fullfile(article_folder, ['onesample_', filename(1:end-4)]);
- if ~exist(onesample_path, 'dir')
- mkdir(onesample_path)
- end
- zFC_path = fullfile(article_folder, ['zFC_', filename(1:end-4)]);
- if ~exist(zFC_path, 'dir')
- mkdir(zFC_path)
- end
- % Proceed to generate and combine ROI spheres
- [coord, ROIs] = xlsread([path, filesep, 'Articles_Included_Excel', filesep, filename(1:end-4), '.xlsx']);
- output_path = ROI_Seeds_path;
- combined_mask = ROI_ball_gen_combined(coord, ROIs, [support_path, filesep, 'BNA_mask_3m.nii'], 4, output_path);
- % Loop through each participant's directory to process BOLD files
- Data_dir = 'F:\test\data\AMUD'; % Specify the path where the 4D NIfTI time series data are stored
- participant_folders = dir(fullfile(Data_dir, '*'));
- participant_folders = participant_folders(~ismember({participant_folders.name}, {'.', '..'}));
- Mask_BNA = spm_read_vols(spm_vol(fullfile(support_path, 'BNA_mask_3m.nii')));
- Mask_Brain = spm_read_vols(spm_vol(fullfile(support_path, 'BrainMask_05_61x73x61.img')));
- for p = 1:length(participant_folders)
- boldFiles = dir(fullfile(Data_dir, participant_folders(p).name, '*.nii'));
- boldFile = fullfile(boldFiles.folder, boldFiles.name);
- bold_vol = spm_vol(boldFile);
- boldData = spm_read_vols(bold_vol);
- boldData = boldData .* Mask_Brain;
- boldData2D = reshape(boldData, [], size(boldData, 4));
- roiTimeSeries = mean(boldData2D(combined_mask > 0, :), 1);
- maskIndex = Mask_Brain > 0;
- boldDataMasked = boldData2D(maskIndex(:), :);
- fcMap = corr(roiTimeSeries', boldDataMasked');
- zfcMap = zeros(size(boldData, 1), size(boldData, 2), size(boldData, 3));
- zfcMap(maskIndex) = atanh(fcMap);
- zFC_filename = fullfile(zFC_path, ['zFC_', participant_folders(p).name, '.nii']);
- zFC_vol = bold_vol(1);
- zFC_vol.fname = zFC_filename;
- spm_write_vol(zFC_vol, zfcMap);
- end
- zFC_files = spm_select('FPList', zFC_path, '^zFC_.*\.nii$');
- if isempty(zFC_files)
- warning('No zFC files found in %s.', zFC_path);
- continue;
- end
- % Setup the statistical design for one-sample t-tests in SPM
- matlabbatch = [];
- matlabbatch{1}.spm.stats.factorial_design.dir = {onesample_path};
- matlabbatch{1}.spm.stats.factorial_design.des.t1.scans = cellstr(zFC_files);
- matlabbatch{1}.spm.stats.factorial_design.cov = struct('c', {}, 'cname', {}, 'iCFI', {}, 'iCC', {});
- matlabbatch{1}.spm.stats.factorial_design.masking.tm.tm_none = 1;
- matlabbatch{1}.spm.stats.factorial_design.masking.im = 1;
- matlabbatch{1}.spm.stats.factorial_design.masking.em = {fullfile(support_path, 'BNA_mask_3m.nii,1')};
- matlabbatch{1}.spm.stats.factorial_design.globalc.g_omit = 1;
- matlabbatch{1}.spm.stats.factorial_design.globalm.gmsca.gmsca_no = 1;
- matlabbatch{1}.spm.stats.factorial_design.globalm.glonorm = 1;
- % Model estimation
- matlabbatch{2}.spm.stats.fmri_est.spmmat = {fullfile(onesample_path, 'SPM.mat')};
- % Contrast specification
- matlabbatch{3}.spm.stats.con.spmmat = {fullfile(onesample_path, 'SPM.mat')};
- matlabbatch{3}.spm.stats.con.consess{1}.tcon.name = 'One Sample T-test';
- matlabbatch{3}.spm.stats.con.consess{1}.tcon.weights = 1;
- matlabbatch{3}.spm.stats.con.consess{1}.tcon.sessrep = 'none';
- matlabbatch{3}.spm.stats.con.delete = 0;
- % Run the batch job
- spm_jobman('run', matlabbatch);
- % Load SPM T-map file
- V = spm_vol(fullfile(onesample_path, 'spmT_0001.nii'));
- [X, XYZ] = spm_read_vols(V);
- % Compute p-values for positive T statistics
- P_uncorrected = 1 - spm_Tcdf(X(X > 0), 655); % Adjust the second parameter based on your sample size
- P_sorted = sort(P_uncorrected);
- P_corrected = spm_P_FDR(P_sorted);
- % Reorder corrected P-values
- [~, sort_idx] = sort(P_uncorrected, 'ascend');
- [~, unsort_idx] = sort(sort_idx, 'ascend');
- P_corrected = P_corrected(unsort_idx);
- % Apply FDR threshold
- thresholded_map = zeros(size(X));
- positive_voxel_indices = find(X > 0);
- thresholded_map(positive_voxel_indices(P_corrected < 0.05)) = X(positive_voxel_indices(P_corrected < 0.05));
- % Save the corrected T-map
- V.fname = fullfile(onesample_path, 'spmT_0001_positive_FDR.nii');
- spm_write_vol(V, thresholded_map);
- % Create a new mask image for voxels above threshold
- mask = thresholded_map > 0;
- V.fname = fullfile(onesample_path, 'spmT_0001_positive_FDR_mask.nii');
- spm_write_vol(V, mask);
- end
- %% Step 5: Create and refine group probability maps.
- output_folder_avg = fullfile(radius_Seeds_results, 'Average_probability_map');
- mkdir(output_folder_avg);
- % Initialize the accumulation matrix
- sum_matrix = [];
- % Retrieve paths to all 'onesample_*' subfolders
- onesample_folders = dir(fullfile(radius_Seeds_results, '*', 'onesample_*'));
- num_folders = length(onesample_folders);
- % Iterate through each 'onesample_*' folder and accumulate the contents of each mask file
- for i = 1:num_folders
- parent_folder_name = onesample_folders(i).folder;
- onesample_folder_name = onesample_folders(i).name;
- mask_file = dir(fullfile(parent_folder_name, onesample_folder_name, '*_positive_FDR_mask.nii'));
- if ~isempty(mask_file)
- file_path = fullfile(parent_folder_name, onesample_folder_name, mask_file.name);
- finalVol = spm_vol(file_path);
- [Y, ~] = spm_read_vols(finalVol);
- if isempty(sum_matrix)
- sum_matrix = zeros(size(Y));
- end
- sum_matrix = sum_matrix + Y;
- end
- end
- % Calculate the average
- avg_matrix = sum_matrix / num_folders;
- % Retain values greater than or equal to 0.6
- avg_matrix(avg_matrix < 0.6) = 0;
- % Remove clusters smaller than 30 voxels
- % Use the bwlabeln function to label connected regions
- [L, num] = bwlabeln(avg_matrix, 6);
- % Iterate through each connected region and remove those smaller than 30 voxels
- for j = 1:num
- if sum(L(:) == j) < 30
- avg_matrix(L == j) = 0;
- end
- end
- % Save the final averaged matrix to a new nii file
- final_mask_filename = fullfile(output_folder_avg, 'average_mask_50_30.nii');
- finalVol.fname = final_mask_filename;
- spm_write_vol(finalVol, avg_matrix);
FCNM.m, no license · at the source
Overview
- Department of Radiology, The First Affiliated Hospital of Anhui Medical University, Hefei, China
- Research Center of Clinical Medical Imaging, Anhui Province, Hefei, China
- Anhui Provincial Key Laboratory for Brain Bank Construction and Resource Utilization, Hefei, China
Abstract
Background: Prior neuroimaging studies and meta-analyses investigating brain correlates of placebo analgesia (PA) have yielded neuroanatomically heterogeneous findings, which may be reconciled from a connectomics perspective. The objective of this study was to examine network localization of brain functional alterations related to PA.
Methods: We initially identified PA-induced brain activation alterations (hyper-activation and hypo-activation separately) during experimental pain from 29 published studies with 674 individuals. By combining these implicated dysfunctional brain regions with large-scale discovery (N = 1113) and validation (N = 1093) resting-state functional magnetic resonance imaging datasets, we then employed a novel functional connectivity network mapping approach to construct PA hyper-activation and hypo-activation networks, respectively.
Results: The PA hyper-activation network manifested as a pattern of circumscribed brain regions mainly involving the limbic, default, and frontoparietal networks. By contrast, the PA hypo-activation network comprised a broadly distributed set of brain regions primarily implicating the ventral attention, somatomotor, and subcortical networks.
Conclusions: Our findings regarding the brain network representations of PA may contribute to a deeper understanding of its action mechanisms and provide a neural framework that may inform future clinical translation.
Reproduced under the paper's license (CC BY), from the paper cited above.
Repository
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Availability: 1 check, the latest on 28 September 2026: the link answers (HTTP 200)
- 28 September 2026: the link answers (HTTP 200)
1 file
- Code/
FCNM.m , MATLAB, 221 lines, 1 match
The paper's code and data availability statement is in the Data section.
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Data
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Data availability statement
The data and analysis codes used in the preparation of this article are publicly available at https://
Reproduced under the paper's license (CC BY), from the paper cited above.
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Version 1, 28 September 2026: the first record
Recorded: type, language, journal, volume, pages, dates, 10 authors, 5 keywords, 12 MeSH terms, 4 funders, 99 references.
Cite
This paper
Zhang, X., Sun, X., Huang, W., An, K., Zhao, X., Zhang, D., Zhang, W., Yu, Y., Qian, Y., & Zhu, J. (2026). Brain network representations of placebo analgesia. Psychological medicine, 56, e131. https://
BibTeX
@article{zhang2026brain,
author = {Zhang, Xiaohan and Sun, Xuetian and Huang, Weisheng and An, Kaijie and Zhao, Xufeng and Zhang, Dan and Zhang, Wenwei and Yu, Yongqiang and Qian, Yinfeng and Zhu, Jiajia},
title = {{Brain network representations of placebo analgesia}},
journal = {Psychological medicine},
year = {2026},
month = may,
volume = {56},
pages = {e131},
publisher = {Cambridge University Press},
issn = {0033-2917},
doi = {10.1017/
url = {https://
pmid = {42083871},
pmcid = {PMC13161808}
}
RIS
TY - JOUR
AU - Zhang, Xiaohan
AU - Sun, Xuetian
AU - Huang, Weisheng
AU - An, Kaijie
AU - Zhao, Xufeng
AU - Zhang, Dan
AU - Zhang, Wenwei
AU - Yu, Yongqiang
AU - Qian, Yinfeng
AU - Zhu, Jiajia
TI - Brain network representations of placebo analgesia
T2 - Psychological medicine
J2 - Psychol Med
PY - 2026
DA - 2026/
VL - 56
SP - e131
SN - 0033-2917
PB - Cambridge University Press
DO - 10.1017/
UR - https://
LA - en
ER -
CSL-JSON
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"container-title": "Psychological medicine",
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"family": "Zhang",
"given": "Xiaohan"
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"publisher": "Cambridge University Press",
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"language": "en",
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