It has been repeatedly shown that specific brain activity related to planning movement develops before the conscious intention to act. This empirical finding strongly challenges the notion of free will. Here, we demonstrate that in the Libet experiment, spontaneous fluctuations of the slow electro-cortical potentials (SCPs) account for a significant fraction of the readiness potential (RP). The individual potential shifts preceding self-initiated movements were classified as showing a negative or positive shift. The negative and positive potential shifts were analyzed in a self-initiated movement condition and in a no-movement condition. Comparing the potential shifts between both conditions, we observed no differences in the early part of the potential. This reveals that the apparently negative RP emerges through an unequal ratio of negative and positive potential shifts. These results suggest that ongoing negative shifts of the SCPs facilitate self-initiated movement but are not related to processes underlying preparation or decision to act.
This is a preview of subscription content, access via your institution.
Buy single article
Instant access to the full article PDF.
Tax calculation will be finalised during checkout.
Subscribe to journal
Immediate online access to all issues from 2019. Subscription will auto renew annually.
Tax calculation will be finalised during checkout.
Bennett MR, Hacker PMS (2003) Philosophical foundations of neuroscience. Wiley-Blackwell, Oxford
Birbaumer N, Elbert T, Canavan AGM, Rockstroh B (1990) Slow potential of the cerebral cortex and behavior. Physiol Rev 70(1):1–41
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(1):9–21
Guggisberg AG, Mottat AM (2013) Timing and awareness of movement decisions: does consciousness really come too late? Front Hum Neurosci 7:385. doi:10.3389/fnhum.2013.00385
Haggard P (2008) Human volition: towards a neuroscience of will. Nat Rev Neurosci 9(12):934–946
Haggard P, Eimer M (1999) On the relation between brain potentials and the awareness of voluntary movements. Exp Brain Res 126(1):128–133
Herrmann CS, Pauen M, Min BK, Busch NA, Rieger JW (2008) Analysis of a choice-reaction task yields a new interpretation of Libet’s experiment. Int J Psychophysiol 67:151–157
Keller I, Heckhausen H (1990) Readiness potentials preceding spontaneous motor acts: voluntary vs. involuntary control. Electroencephalogr Clin Neurophysiol 76:351–361
Kornhuber HH, Deecke L (1965) Hirnpotentialänderungen bei Willkürbewegungen und passiven Bewegungen des Menschen: bereitschaftspotential und reafferente Potentiale. Pflügers Archive 284(1):1–17
Kotchoubey B (2012) Why are you free? Neurobiology and psychology of voluntary action. Nova Sci Pub, New York
Libet B (1985) Unconscious cerebral initiative and the role of conscious will in voluntary action. Behav Brain Sci 8(4):529–566
Libet B, Gleason CA, Wright EW, Pearl DK (1983) Time of conscious intention to act in relation to onset of cerebral activity (readiness-potential). The unconscious initiation of a freely voluntary act. Brain 106(3):623–642
McCallum WC, Curry SH (1993) Slow potential changes in the human brain. Springer, Berlin
Miller J, Shepherdson P, Trevena J (2011) Effects of clock monitoring on electroencephalographic activity: is unconscious movement intention an artifact of the clock? Psychol Sci 22(1):103–109
Mitzdorf U (1985) Current source-density method and application in cat cerebral cortex: investigation of evoked potentials and EEG phenomena. Physiol Rev 65(1):37–100
Rigoni D, Kühn S, Sartori G, Brass M (2011) Inducing disbelief in free will alters brain correlates of preconscious motor preparation: the brain minds whether we believe in free will or not. Psychol Sci 22(5):613–618
Schlegel A, Alexander P, Sinnott-Armstrong W, Roskies A, Tse PT, Wheatley T (2013) Braking up the wrong free: readiness potentials reflect processes independent of conscious will. Exp Brain Res 229(3):329–335
Schurger A, Sitt JD, Dehaene S (2012) An accumulator model for spontaneous neural activity prior to self-initiated movement. Proc Natl Acad Sci 109(42):E2904–E2913
Shibasaki H, Hallet M (2006) What is the bereitschaftspotential? Clin Neurophysiol 117(11):2341–2356
Sirigui A, Daprati E, Ciancia S, Giraux P, Nighoghossian N, Posada A, Haggard P (2004) Altered awareness of voluntary action after damage to the parietal cortex. Nat Neurosci 7(1):80–84
Trevena J, Miller J (2010) Brain preparation before a voluntary action: evidence against unconscious movement initiation. Conscious Cogn 19:447–456
VaezMousavi SM, Barry RJ (1993) Positive and negative shifts of the readiness potential: preparatory effects. Int J Psychophysiol 15(2):105–113
Electronic supplementary material
Below is the link to the electronic supplementary material.
About this article
Cite this article
Jo, HG., Hinterberger, T., Wittmann, M. et al. Spontaneous EEG fluctuations determine the readiness potential: is preconscious brain activation a preparation process to move?. Exp Brain Res 231, 495–500 (2013). https://doi.org/10.1007/s00221-013-3713-z
- Free will
- Intention to move
- Libet experiment
- Slow cortical potential
- Readiness potential