{"doi":"10.1016/j.brs.2020.06.003","title":"Localizing central swallowing functions by combining non-invasive brain stimulation with neuroimaging","abstract":"Swallowing is a complex sensorimotor process, which involves precise temporal coordination of the upper and lower lips, tongue, and pharyngeal and esophageal musculatures. This integrated process is controlled by neural interplay across cortical and subcortical networks. Although numerous functional brain imaging studies have suggested means to measure post-stroke pathological changes in the cortical control region of swallowing [[1]de Lima M.S. Mangilli L.D. Sassi F.C. de Andrade C.R.F. Functional magnetic resonance and swallowing: critical literature review.Braz J Otorhinolaryngol. 2015 Dec; 81: 671-680Crossref PubMed Scopus (3) Google Scholar], identifying the precise functional localization of the motor area for swallowing has been challenging. This complexity is partly due to the extensive cortical network that executes the swallowing function [[2]Kern M.K. Birn R. Jaradeh S. Jesmanowicz A. Cox R. Hyde J. et al.Swallow-related cerebral cortical activity maps are not specific to deglutition.Am J Physiol Gastrointest Liver Physiol. 2001 Apr; 280: G531-G538Crossref PubMed Google Scholar]. Transcranial magnetic stimulation (TMS) has been proposed and used as a powerful tool for functional localization of swallowing function [[3]Macrae P.R. Jones R.D. Huckabee M.-L. The effect of swallowing treatments on corticobulbar excitability: a review of transcranial magnetic stimulation induced motor evoked potentials.J Neurosci Methods. 2014 Aug; 233: 89-98Crossref PubMed Scopus (12) Google Scholar]. However, because pharyngeal motor cortex (M1) representation of the intrinsic swallowing muscles is overlaid by those of the tongue and jaw in the somatotopic organization of the motor cortex, localization of swallowing area is substantially more challenging than the standard motor mapping of the hand area. This makes the administering of the non-invasive stimulation to relevant swallowing areas as well as the recording of the elicited muscle responses particularly challenging. As a solution, we propose that surface electromyography (sEMG) recordings of lip orbicularis oris (OO) muscle activities elicited by a functional MRI (fMRI)-guided neuronavigated TMS (nTMS) technique would aid in the detection of the submental complex (SMC) muscles’ motor evoked potentials (MEPs) for localization of the SMC target in pharyngeal M1. We hypothesized that the lip OO target as a control target, could readily assist us in determining the SMC target (the candidate target). This hypothesis was made based on the previous studies in which the OO muscle was localized in the motor cortex during lip-pursing tasks using the rTMS procedure [[4]Möttönen R. Rogers J. Watkins K.E. Stimulating the lip motor cortex with transcranial magnetic stimulation.JoVE. 2014 Jun 14; Crossref Scopus (20) Google Scholar]. The OO muscle is an important orofacial muscle for initiating the swallowing function by creating and maintaining an adequate labial seal that prevents foods or liquids from leaking out of the mouth during mastication and the swallowing reflex. In addition, it plays critical roles in speech articulation and facial expressions. Therefore, mapping the lip motor area would not only provide an efficient means to precisely determine the SMC targeting intervention for rehabilitation of dysphagia, but also gives insight into therapeutic techniques for restoring lip functions in speech articulation and other lip muscle activities. Three healthy adult volunteer subjects (age = 32.0 years; 1 female and 2 males) participated in this pilot study. Each subject participated in three study visits including the fMIR scan session, the TMS MEPs session, and the continuous theta burst transcranial magnetic stimulation (cTBS) session (please see Supplemental Materials for details) at the Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital (MGH). For the validation of the central swallowing control, fMRI scans were obtained from each subject during a l","journal":"Brain stimulation","year":2020,"id":112815,"datarank":0.23489424494087657,"base_score":1.0986122886681096,"endowment":1.0986122886681096,"self_citation_contribution":0.16479184330021646,"citation_network_contribution":0.0701024016406601,"self_endowment_contribution":0.16479184330021646,"citer_contribution":0.0701024016406601,"corpus_percentile":null,"corpus_rank":null,"citation_count":2,"citer_count":2,"citers_with_citation_signal":2,"citers_with_endowment":2,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9574,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2020-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":533272,"name":"Marziye Eshghi","orcid":"0000-0003-1270-6521","position":1,"is_corresponding":false},{"id":308515,"name":"Sheraz Khan","orcid":"0000-0002-6792-3577","position":2,"is_corresponding":false},{"id":251970,"name":"Qiyuan Tian","orcid":"0000-0002-8350-5295","position":3,"is_corresponding":false},{"id":473704,"name":"Juho Joutsa","orcid":"0000-0002-3457-9415","position":4,"is_corresponding":false},{"id":244776,"name":"Yangming Ou","orcid":"0000-0002-7726-6208","position":5,"is_corresponding":false},{"id":364860,"name":"Qing Mei Wang","orcid":"0000-0003-4655-4917","position":6,"is_corresponding":false},{"id":289036,"name":"Jian Kong","orcid":"0000-0002-2744-6067","position":7,"is_corresponding":false},{"id":63233,"name":"Bruce R. Rosen","orcid":"0000-0002-8576-0839","position":8,"is_corresponding":false},{"id":250071,"name":"Jyrki Ahveninen","orcid":"0000-0001-9058-8669","position":9,"is_corresponding":false},{"id":297460,"name":"Aapo Nummenmaa","orcid":"0000-0002-6452-7958","position":10,"is_corresponding":false},{"id":533271,"name":"Shasha Li","orcid":"0000-0002-2498-6893","position":0,"is_corresponding":true}],"reference_count":10,"raw_metadata":{"citation_network_status":"fetched"},"created_at":"2026-07-18T23:13:17.845093Z","pmid":"32504829","pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}