{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,26]],"date-time":"2026-03-26T15:41:26Z","timestamp":1774539686701,"version":"3.50.1"},"reference-count":41,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2016,3,5]],"date-time":"2016-03-05T00:00:00Z","timestamp":1457136000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Quaternions can be used as an alternative to model the fundamental patterns of electroencephalographic (EEG) signals in the time domain. Thus, this article presents a new quaternion-based technique known as quaternion-based signal analysis (QSA) to represent EEG signals obtained using a brain-computer interface (BCI) device to detect and interpret cognitive activity. This quaternion-based signal analysis technique can extract features to represent brain activity related to motor imagery accurately in various mental states. Experimental tests in which users where shown visual graphical cues related to left and right movements were used to collect BCI-recorded signals. These signals were then classified using decision trees (DT), support vector machine (SVM) and k-nearest neighbor (KNN) techniques. The quantitative analysis of the classifiers demonstrates that this technique can be used as an alternative in the EEG-signal modeling phase to identify mental states.<\/jats:p>","DOI":"10.3390\/s16030336","type":"journal-article","created":{"date-parts":[[2016,3,7]],"date-time":"2016-03-07T10:25:00Z","timestamp":1457346300000},"page":"336","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":23,"title":["Quaternion-Based Signal Analysis for Motor Imagery Classification from Electroencephalographic Signals"],"prefix":"10.3390","volume":"16","author":[{"given":"Patricia","family":"Batres-Mendoza","sequence":"first","affiliation":[{"name":"Laboratorio de Sistemas Bioinspirados, Departamento de Ingenier\u00eda Electr\u00f3nica, DICIS, Universidad de Guanajuato, Carr. Salamanca-Valle de Santiago KM. 3.5 + 1.8 Km., Salamanca 36885, Mexico"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Carlos","family":"Montoro-Sanjose","sequence":"additional","affiliation":[{"name":"Departamento de Arte y Empresa, DICIS, Universidad de Guanajuato, Carr. Salamanca-Valle de Santiago KM. 3.5 + 1.8 Km., Salamanca 36885, Mexico"},{"name":"Cuerpo Acad\u00e9mico de Telem\u00e1tica, DICIS, Universidad de Guanajuato, Carr. Salamanca-Valle de Santiago KM. 3.5 + 1.8 Km., Salamanca 36885, Mexico"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Erick","family":"Guerra-Hernandez","sequence":"additional","affiliation":[{"name":"Laboratorio de Sistemas Bioinspirados, Departamento de Ingenier\u00eda Electr\u00f3nica, DICIS, Universidad de Guanajuato, Carr. Salamanca-Valle de Santiago KM. 3.5 + 1.8 Km., Salamanca 36885, Mexico"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3373-0929","authenticated-orcid":false,"given":"Dora","family":"Almanza-Ojeda","sequence":"additional","affiliation":[{"name":"Laboratorio de Procesamiento Digital de Se\u00f1ales, Departamento de Ingenier\u00eda Electr\u00f3nica, DICIS, Universidad de Guanajuato, Carr. Salamanca-Valle de Santiago KM. 3.5 + 1.8 Km., Salamanca 36885, Mexico"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7530-9027","authenticated-orcid":false,"given":"Horacio","family":"Rostro-Gonzalez","sequence":"additional","affiliation":[{"name":"Laboratorio de Sistemas Bioinspirados, Departamento de Ingenier\u00eda Electr\u00f3nica, DICIS, Universidad de Guanajuato, Carr. 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