Medical & Biological Engineering & Computing

, Volume 48, Issue 4, pp 343–350 | Cite as

Discrimination of left and right leg motor imagery for brain–computer interfaces

  • Peter BoordEmail author
  • Ashley Craig
  • Yvonne Tran
  • Hung Nguyen
Original Article


This article reports on a study to identify electroencephalography (EEG) signals with potential to provide new BCI channels through mental motor imagery (MMI). Leg motion was assessed to see if left and right leg MMI could be discriminated in the EEG. The study also explored simultaneous observation of leg movement as a means to enhance MMI evoked EEG signals. The results demonstrate that MMI of the left and right leg produce a contralateral preponderance of EEG alpha band desynchronization, which can be spatially discriminated. This suggests that lower extremity MMI could provide signals for additional BCI channels. The study also shows that movement imitation enhances alpha band desynchronization during MMI, and might provide a useful aid in the identification and training of BCI signals.


Mental motor imagery Brain–computer interfaces EEG Leg Movement imitation 


  1. 1.
    Allison T, McCarthy G, Luby M, Puce A, Spencer DD (1996) Localization of functional regions of human mesial cortex by somatosensory evoked potential recording and by cortical stimulation. Electroenceph Clin Neurophysiol 100:126–140CrossRefGoogle Scholar
  2. 2.
    Barlow JS (1993) The electroencephalogram: its patterns and origins. MIT Press, Cambridge, MAGoogle Scholar
  3. 3.
    Bear M, Bear MF, Connors BW, Paradiso MA (2005) Neuroscience: exploring the brain, 2nd edn. Williams and Wilkins, Baltimore, MDGoogle Scholar
  4. 4.
    Boord P, Barriskill A, Craig A, Nguyen H (2004) Brain computer interface-FES integration: towards a hands-free neuroprosthesis command system. Neuromodulation 7:267–276CrossRefGoogle Scholar
  5. 5.
    Decety J, Perani D, Jeannerod M, Bettinardi V, Tadary B, Woods R, Mazziotta JC, Fazio F (2002) Mapping motor representations with positron emission tomography. Nature 371:600–602CrossRefGoogle Scholar
  6. 6.
    Delorme A, Makeig S (2004) EEGLAB: an open source toolbox for analysis of single-trial EEG dynamics including independent component analysis. J Neurosci Methods 134:9–21CrossRefGoogle Scholar
  7. 7.
    Fadiga L, Fogassi L, Pavesi G, Rizzolatti G (1995) Motor facilitation during action observation: a magnetic stimulation study. J Neurophysiol 73:2608–2611Google Scholar
  8. 8.
    Grafton ST, Fadiga L, Arbib MA, Rizzolatti G (1997) Premotor cortex activation during observation and naming of familiar tools. Neuroimage 6:231–236CrossRefGoogle Scholar
  9. 9.
    Hari R, Salmelin R, Makela JP, Salenius S, Helle M (1997) Magnetoencephalographic cortical rhythms. Int J Psychophysiol 26:51–62CrossRefGoogle Scholar
  10. 10.
    Hari R, Forss N, Avikainen S, Kirveskari E, Salenius S, Rizzolatti G (1998) Activation of human primary motor cortex during action observation: a neuromagnetic study. Proc Natl Acad Sci USA 95:15061–15065CrossRefGoogle Scholar
  11. 11.
    Hjorth B (1975) An on-line transformation of EEG scalp potentials into orthogonal source derivations. Electroencephal Clin Neurophysiol 39:526–530CrossRefGoogle Scholar
  12. 12.
    Hwang HJ, Kwon K, Im CH (2009) Neurofeedback-based motor imagery training for brain–computer interface (BCI). J Neuroscience Methods 179:150–156CrossRefGoogle Scholar
  13. 13.
    Iacoboni M, Woods RP, Brass M, Bekkering H, Mazziotta JC, Rizzolatti G (1999) Cortical mechanisms of human imitation. Science 286:2526–2528CrossRefGoogle Scholar
  14. 14.
    Jung TP, Makeig S, Humphries C, Lee TW, McKeown MJ, Iragui V, Sejnowski TJ (2000) Removing electroencephalographic artifacts by blind source separation. Psychophysiol 37:163–178CrossRefGoogle Scholar
  15. 15.
    Klem GH, Luders HO, Jasper HH, Elger C (1999) The ten–twenty electrode system of the International Federation. Electroenceph Clin Neurophysiol S52:3–6Google Scholar
  16. 16.
    Krausz G, Scherer R, Korisek G, Pfurtscheller G (2003) Critical decision-speed and information transfer in the “Graz Brain–Computer Interface”. Appl Psychophysiol Biofeed 28:233–240CrossRefGoogle Scholar
  17. 17.
    Lauer RT, Peckham PH, Kilgore KL (1999) EEG-based control of a hand grasp neuroprosthesis. Neuroreport 10:1767–1771CrossRefGoogle Scholar
  18. 18.
    Müller-Putz GR, Scherer R, Pfurtscheller G, Rupp R (2005) EEG-based neuroprosthesis control: a step towards clinical practice. Neurosci Lett 382:169–174CrossRefGoogle Scholar
  19. 19.
    Neuper C, Pfurtscheller G (1996) Post-movement synchronization of beta rhythms in the EEG over the cortical foot area in man. Neurosci Lett 216:17–20CrossRefGoogle Scholar
  20. 20.
    Neuper C, Pfurtscheller G (1999) Motor imagery and ERD. In G. Pfurtscheller & F. H. Lopes da Silva (Eds.), Event-Related Desynchronization, Handbook of Electroenceph. and Clin. Neurophysiol., rev. ed., vol. 6: 303-325. Amsterdam, The Netherlands: ElsevierGoogle Scholar
  21. 21.
    Neuper C, Scherer R, Wriessnegger S, Pfurtscheller G (2009) Motor imagery and action observation: modulation of sensorimotor brain rhythms during mental control of a brain–computer interface. Clin Neurophysiol 120:239–247CrossRefGoogle Scholar
  22. 22.
    Nishitani N, Hari R (2000) Temporal dynamics of cortical representation for action. Proc Natl Acad Sci USA 97:913–918CrossRefGoogle Scholar
  23. 23.
    Obermaier B, Neuper C, Guger C, Pfurtscheller G (2001) Information transfer rate in a five-classes brain–computer interface. IEEE Trans Neural Sys Rehab Eng 9:283–288CrossRefGoogle Scholar
  24. 24.
    Obermaier B, Muller GR, Pfurtscheller G (2003) “Virtual keyboard” controlled by spontaneous EEG activity. IEEE Trans Neural Sys Rehab Eng 11:422–426CrossRefGoogle Scholar
  25. 25.
    Pfurtscheller G, Lopes da Silva FH (2004) Event-related desynchronization. Elsevier, AmsterdamGoogle Scholar
  26. 26.
    Pfurtscheller G, Neuper C, Andrew C, Edlinger G (1997) Foot and hand area mu rhythms. Int J Psychophysiol 26:121–135CrossRefGoogle Scholar
  27. 27.
    Pfurtscheller G, Neuper C, Flotzinger D, Pregenzer M (1997) EEG-based discrimination between imagination of right and left hand movement. Electroenceph Clin Neurophysiol 103:642–651CrossRefGoogle Scholar
  28. 28.
    Pfurtscheller G, Pichler-Zalaudek K, Neuper C (1999) ERD and ERS in voluntary movement of different limbs. In G. Pfurtscheller & F. H. Lopes da Silva (Eds.), Event-Related Desynchronization, Handbook of Electroenceph. and Clin. Neurophysiol., rev. ed., vol. 6: 245-268. Amsterdam, The Netherlands: ElsevierGoogle Scholar
  29. 29.
    Pfurtscheller G, Neuper C, Krausz G (2000) Functional dissociation of lower and upper frequency mu rhythms in relation to voluntary limb movement. Clin Neurophysiol 111:1873–1879CrossRefGoogle Scholar
  30. 30.
    Pfurtscheller G, Guger C, Müller G, Krausz G, Neuper C (2000) Brain oscillations control hand orthosis in a tetraplegic. Neurosci Lett 292:211–214CrossRefGoogle Scholar
  31. 31.
    Rizzolatti G, Fadiga L, Gallese V, Fogassi L (1996) Premotor cortex and the recognition of motor actions. Brain Res Cogn Brain Res 3:131–141CrossRefGoogle Scholar
  32. 32.
    Scherer R, Muller GR, Neuper C, Graimann B, Pfurtscheller G (2004) An asynchronously controlled EEG-based virtual keyboard: improvement of the spelling rate. IEEE Trans Bio-Med Eng 51:979–984CrossRefGoogle Scholar
  33. 33.
    Siddall PJ, Taylor DA, McClelland JM, Rutkowski SB, Cousins MJ (1999) Pain report and the relationship of pain to physical factors in the first 6 months following spinal cord injury. Pain 81:187–197CrossRefGoogle Scholar
  34. 34.
    Tran Y, Craig A, Boord P, Craig D (2004) Using independent component analysis to remove artifact from electroencephalographic measured during stuttered speech. Med Biol Eng Comput 42:627–633CrossRefGoogle Scholar
  35. 35.
    van Burik M, Edlinger G, Pfurtscheller G (1999) Spatial mapping of ERD/ERS. In G. Pfurtscheller & F. H. Lopes da Silva (Eds.), Event-Related Desynchronization, in Handbook of Electroencephalography and Clinical Neurophysiology; rev. ser. v.6: 107-118. Elsevier ScienceGoogle Scholar
  36. 36.
    Wolpaw JR, McFarland DJ (1994) Multichannel EEG-based brain–computer communication. Electroenceph Clin Neurophysiol 90:444–449CrossRefGoogle Scholar

Copyright information

© International Federation for Medical and Biological Engineering 2010

Authors and Affiliations

  • Peter Boord
    • 1
    Email author
  • Ashley Craig
    • 2
  • Yvonne Tran
    • 2
  • Hung Nguyen
    • 3
  1. 1.Brain Resource Ltd.UltimoAustralia
  2. 2.Rehabilitation Studies UnitUniversity of SydneyRydeAustralia
  3. 3.Faculty of Engineering and Information TechnologyUniversity of Technology SydneyUltimoAustralia

Personalised recommendations