<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE article PUBLIC "-//NLM//DTD Journal Publishing DTD v2.0 20040830//EN" "journalpublishing.dtd"><article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" dtd-version="2.0" xml:lang="en" article-type="letter"><front><journal-meta><journal-id journal-id-type="nlm-ta">JMIR Res Protoc</journal-id><journal-id journal-id-type="publisher-id">ResProt</journal-id><journal-id journal-id-type="index">5</journal-id><journal-title>JMIR Research Protocols</journal-title><abbrev-journal-title>JMIR Res Protoc</abbrev-journal-title><issn pub-type="epub">1929-0748</issn><publisher><publisher-name>JMIR Publications</publisher-name><publisher-loc>Toronto, Canada</publisher-loc></publisher></journal-meta><article-meta><article-id pub-id-type="publisher-id">v15i1e87420</article-id><article-id pub-id-type="doi">10.2196/87420</article-id><article-categories><subj-group subj-group-type="heading"><subject>Letter to the Editor</subject></subj-group></article-categories><title-group><article-title>Bridging Neurofeedback and Structural Connectivity in Chronic Pain</article-title></title-group><contrib-group><contrib contrib-type="author" corresp="yes"><name name-style="western"><surname>Acar</surname><given-names>Alaeddin</given-names></name><degrees>MD</degrees><xref ref-type="aff" rid="aff1">1</xref></contrib><contrib contrib-type="author"><name name-style="western"><surname>Yahya</surname><given-names>Diaa</given-names></name><degrees>MD</degrees><xref ref-type="aff" rid="aff2">2</xref></contrib><contrib contrib-type="author"><name name-style="western"><surname>Tekirda&#x015F;</surname><given-names>Eray</given-names></name><degrees>MD</degrees><xref ref-type="aff" rid="aff3">3</xref></contrib></contrib-group><aff id="aff1"><institution>Department of Neurosurgery, Kulu State Hospital</institution><addr-line>No 4, 139518 Street, Dinek, Kulu</addr-line><addr-line>Konya</addr-line><country>Turkey</country></aff><aff id="aff2"><institution>Department of Neurosurgery, Bucak State Hospital</institution><addr-line>Burdur</addr-line><country>Turkey</country></aff><aff id="aff3"><institution>Department of Neurosurgery, Malatya Training and Research Hospital</institution><addr-line>Malatya</addr-line><country>Turkey</country></aff><contrib-group><contrib contrib-type="editor"><name name-style="western"><surname>Schwartz</surname><given-names>Amy</given-names></name></contrib></contrib-group><author-notes><corresp>Correspondence to Alaeddin Acar, MD, Department of Neurosurgery, Kulu State Hospital, No 4, 139518 Street, Dinek, Kulu, Konya, 42770, Turkey, 90 5424723723; <email>alaeacar@gmail.com</email></corresp></author-notes><pub-date pub-type="collection"><year>2026</year></pub-date><pub-date pub-type="epub"><day>28</day><month>1</month><year>2026</year></pub-date><volume>15</volume><elocation-id>e87420</elocation-id><history><date date-type="received"><day>08</day><month>11</month><year>2025</year></date><date date-type="accepted"><day>08</day><month>12</month><year>2025</year></date></history><copyright-statement>&#x00A9; Alaeddin Acar, Diaa Yahya, Eray Tekirda&#x015F;. Originally published in JMIR Research Protocols (<ext-link ext-link-type="uri" xlink:href="https://www.researchprotocols.org">https://www.researchprotocols.org</ext-link>), 28.1.2026. </copyright-statement><copyright-year>2026</copyright-year><license license-type="open-access" xlink:href="https://creativecommons.org/licenses/by/4.0/"><p>This is an open-access article distributed under the terms of the Creative Commons Attribution License (<ext-link ext-link-type="uri" xlink:href="https://creativecommons.org/licenses/by/4.0/">https://creativecommons.org/licenses/by/4.0/</ext-link>), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work, first published in JMIR Research Protocols, is properly cited. The complete bibliographic information, a link to the original publication on <ext-link ext-link-type="uri" xlink:href="https://www.researchprotocols.org">https://www.researchprotocols.org</ext-link>, as well as this copyright and license information must be included.</p></license><self-uri xlink:type="simple" xlink:href="https://www.researchprotocols.org/2026/1/e87420"/><related-article related-article-type="commentary article" ext-link-type="doi" xlink:href="10.2196/78806" xlink:title="Comment on" xlink:type="simple">https://www.researchprotocols.org/2025/1/e78806</related-article><related-article related-article-type="commentary" ext-link-type="doi" xlink:href="10.2196/89007" xlink:title="Comment in" xlink:type="simple">https://www.researchprotocols.org/2026/1/e89007</related-article><kwd-group><kwd>brain-computer interface</kwd><kwd>brain oscillations</kwd><kwd>chronic pain</kwd><kwd>electroencephalography</kwd><kwd>musculoskeletal</kwd><kwd>neuromodulation</kwd></kwd-group></article-meta></front><body><p>We read with great interest and appreciation the article by Bialostocki et al [<xref ref-type="bibr" rid="ref1">1</xref>] published in <italic>JMIR Research Protocols</italic>. The authors present an innovative electroencephalography-based neurofeedback (EEG-NF) protocol targeting abnormal activity in the right insula (RIns) and dorsal anterior cingulate cortex (dACC) [<xref ref-type="bibr" rid="ref1">1</xref>].</p><p>The authors&#x2019; goal of exploring the functional connectivity between these two key regions is particularly noteworthy. This approach aims to modulate the &#x201C;salience network,&#x201D; which is involved in processing the emotional-motivational aspects of pain and includes the RIns and dACC as key nodes [<xref ref-type="bibr" rid="ref2">2</xref>].</p><p>At this point, we would like to offer a constructive contribution by approaching the protocol&#x2019;s underlying mechanism from a neurosurgical perspective. This functional circuit involving the RIns and dACC is thought to operate, at least in part, on a structural foundation provided by the cingulum bundle [<xref ref-type="bibr" rid="ref2">2</xref>].</p><p>This connection is important because invasive modulation of this circuit is a long-established neurosurgical procedure. Anterior cingulotomy is used as a &#x201C;last resort&#x201D; option for treatment-resistant, intractable chronic pain syndromes, especially when the affective component of pain is dominant [<xref ref-type="bibr" rid="ref3">3</xref>]. This procedure creates ablative lesions in the cingulum bundle, permanently interrupting the circuit that Bialostocki et al [<xref ref-type="bibr" rid="ref1">1</xref>] aim to noninvasively &#x201C;downtrain.&#x201D; It is well documented that anterior cingulotomy reduces the emotional response to pain and the component of suffering, rather than the pain intensity itself [<xref ref-type="bibr" rid="ref3">3</xref>], which is a close parallel to the known functions of the RIns and dACC.</p><p>The EEG-NF protocol presented by Bialostocki et al [<xref ref-type="bibr" rid="ref1">1</xref>] may therefore be viewed, at least conceptually, as a noninvasive counterpart to this invasive surgical approach. Given this parallel, the inclusion of structural imaging methods, such as diffusion tensor imaging (DTI), could add great value to the protocol. The literature, including a systematic review of DTI in migraine, a chronic pain disorder, has shown that the microstructural integrity of key white matter tracts (eg, reduced fractional anisotropy in thalamic radiations, corpus callosum, cingulum, and association fibers) is frequently altered [<xref ref-type="bibr" rid="ref4">4</xref>].</p><p>This raises two important questions for future studies:</p><list list-type="order"><list-item><p>Could the pretreatment structural integrity of the cingulum bundle, as measured by DTI, be used as a biomarker to predict a patient&#x2019;s response to this EEG-NF therapy?</p></list-item><list-item><p>Can a successful neurofeedback intervention lead to measurable neuroplastic changes in the cingulum bundle, as measured by DTI? Indeed, a strong relationship between functional and structural connectivity has been reported [<xref ref-type="bibr" rid="ref5">5</xref>].</p></list-item></list><p>In conclusion, we believe that adding structural DTI analysis to the innovative protocol by Bialostocki et al [<xref ref-type="bibr" rid="ref1">1</xref>] may deepen the understanding of the targeted mechanisms, help bridge the gap between noninvasive neuromodulation and invasive neurosurgery, and aid in optimizing patient selection for larger clinical trials in the future.</p></body><back><ack><p>Google Gemini was used for language editing.</p></ack><fn-group><fn fn-type="conflict"><p>None declared.</p></fn></fn-group><glossary><title>Abbreviations </title><def-list><def-item><term id="abb1">dACC</term><def><p>dorsal anterior cingulate cortex</p></def></def-item><def-item><term id="abb2">DTI</term><def><p>diffusion tensor imaging</p></def></def-item><def-item><term id="abb3">EEG-NF</term><def><p>electroencephalography 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