Bereitschaftspotential
[1] In the spring of 1964 Hans Helmut Kornhuber (then docent and chief physician at the department of neurology, head Professor Richard Jung, university hospital Freiburg im Breisgau) and Lüder Deecke (his doctoral student) went for lunch to the 'Gasthaus zum Schwanen' at the foot of the Schlossberg hill in Freiburg.
Consequently, they decided to look for cerebral potentials in man related to volitional acts and to take voluntary movement as their research paradigm.
[2] The possibility to do research on electrical brain potentials preceding voluntary movements came with the advent of the 'computer of average transients' (CAT computer), invented by Manfred Clynes, the first still simple instrument available at that time in the Freiburg laboratory.
[3] After detailed investigation and control experiments such as passive finger movements the Citation Classic with the term Bereitschaftspotential was published.
[2] The BP is ten to hundred times smaller than the α-rhythm of the EEG; only by averaging, relating the electrical potentials to the onset of the movement it becomes apparent.
Figure shows the typical slow shifts of the cortical DC potential, called Bereitschaftspotential, preceding volitional, rapid flexions of the right index finger.
A very similar event-related potential (ERP) component had earlier been discovered by the British neurophysiologist William Grey Walter in 1962 and published in 1964.
[11] The Bereitschaftspotential was received with great interest by the scientific community, as reflected by Sir John Eccles's comment: "There is a delightful parallel between these impressively simple experiments and the experiments of Galileo Galilei who investigated the laws of motion of the universe with metal balls on an inclined plane".
Recently it has been shown by integrating simultaneously acquired EEG and fMRI that SMA and aMCC have strong reciprocal connections that act to sustain each other’s activity, and that this interaction is mediated during movement preparation according to the Bereitschaftspotential amplitude.
[further explanation needed] In a series of neuroscience of free will experiments in the 1980s, Benjamin Libet studied the relationship between conscious experience of volition and the BP e.g.[20] and found that the BP started about 0.35 sec earlier than the subject's reported conscious awareness that "now he or she feels the desire to make a movement."
[21][22] In 2016, a group around John-Dylan Haynes in Berlin (Germany) determined the time window after the BP in which an intended motion could possibly be cancelled upon command.
[23] The authors tested whether human volunteers could win a "duel" against a BCI (brain–computer interface) designed to predict their movements in real-time from observations of their EEG activity (the BP).
They aimed to determine the exact time at which cancellation (veto) of movements was not possible anymore (the point of no return).
