Hans H. Kornhuber

Hirnpotentialänderungen bei Willkürbewegungen und passiven Bewegungen des Menschen: Bereitschaftspotential und reafferente Potentiale

SummaryA method of chronological data storage and reverse computation is described by which bio-electrical phenomena preceding “spontaneous” events within the nervous system can be analysed if these events appear repeatedly and are capable of triggering a computer.Slow brain potentials accompanying voluntary and passive movements of the limbs were analysed by this method. These potentials were recorded from different points of the scalp from 12 healthy subjects in 94 experiments with more than 100 movements in each record. At times artifacts were superimposed upon cerebral potentials. The former were identified, and, as far as was possible, eliminated.Voluntary hand or foot movements are preceded by a slowly increasing surfacenegative cortical potential of 10–15 μV, called readiness potential. This potential is maximal over the contralateral precentral region, but shows bilateral spread and is larger over the frontal than over the occipital areas. The readiness potential increases with intentional engagement and is reduced by mental indifference of the subject.Voluntary movements are followed by a complex potential with an early positive phase that begins 30–90 msec after the onset of movement. The late potentials following voluntary movements are similar to those after passive movements. Both resemble the late bilateral components of the evoked potentials after electrical stimulation of peripheral nerves. Some variable differences between the early components of the potentials after the onset of active and passive movements require further investigation.No relation between the onset of voluntary movements and the phase of the alpha rhythm could be detected.ZusammenfassungEine Methode zur chronologischen Datenspeicherung und Rückwärtsanalyse hirnelektrischer Begleitvorgänge wiederholter Willkürbewegungen beim Menschen wird beschrieben.Mit dieser Methode wurden langsame Hirnpotentiale 1. bei Willkürbewegungen von Hand und Fuß und 2. bei ähnlichen passiven Handbewegungen bei 12 gesunden Menschen in 94 Versuchen mit je über 100 Bewegungen in 3 Kanälen untersucht. Vor Willkürbewegungen der Hand und des Fußes entsteht ein langsam ansteigendes oberflächen-negatives Hirnpotential von 10–15 μV, das Bereitschaftspotential genannt wird. Sein Maximum liegt über der kontralateralen Präcentralregion bei bilateraler Verteilung über der Schädelkonvexität, frontal größer als occipital. Es wächst mit Aufmerksamkeit und intentionaler Beteiligung der Versuchsperson und nimmt bei Gleichgültigkeit ab. Eine Korrelation des Beginns der Willkürbewegungen zur Phase des Alpharhythmus war nicht nachweisbar. Nach der Willkürbewegung entsteht ein mehrphasisches Potential mit früher Positivierung, die 30–90 msec nach der Bewegung beginnt. Die Hirnpotentiale nach Willkürbewegung ähneln denen nach passiver Bewegung und den späten Komponenten des „evoked potential“ auf elektrischen Medianusreiz. Variable Unterschiede der frühen Potentialänderungen nach aktiven und passiven Bewegungen bedürfen weiterer Untersuchung.Weitergehende Anwendungen der Rückwärtsanalyse werden besprochen. Ähnlichkeiten des Bereitschaftspotentials zur Erwartungswelle G. Walters bei bedingten Reflexen und Quellen von Artefakten durch Augenbewegungen usw. werden diskutiert.

Voluntary finger movement in man: Cerebral potentials and theory

AbstractThree different brain potentials preceeding voluntary rapid finger flexion can be recorded from the skull surface by time reversed averaging. The early cortical activity preceding unilateral movement is bilateral and widespread (Bereitschaftspotential, BP). The same applies for the second potential (pre-motion positivity, PMP). Only the third potential (motor potential, MP) is unilateral and restricted to the contralateral motor cortex. In a total of 87 experiments with 39 subjects, the BP started on the average 750 ms (SD 360, SE 38.5) prior to rapid finger flexion. Its largest amplitude was found mid-parietally and averaged-5.3 μV (SD 2.32, SE 0.4). Such amplitudes were found with averages of 800 and more movements per experiment. However, at the beginning of an experiment the BP is larger. Preceding finger movement, the BP was found bilaterally over the parietal and precentral cortex and over the midline. Over the frontal cortex, either no potential or positivity was recorded. In normal subjects, the BP always begins bilaterally and symmetrically. At parietal leads, it remains bilaterally-symmetrical. A slight contralateral preponderance begins about 400 ms prior to movement only over motor cortex, which becomes statistically significant at 150 ms. When comparing the parietal BP amplitude with the precentral amplitude on the ipsilateral side, where no superposition of the MP occurs, there is more negativity parietally than precentrally, although the parietal skull is about 11% thicker than the precentral. The BP is a negative shift of the cortical DC potential probably representing a preparatory process in the dendritic network of those cortical areas that are involved in the intended movement.The PMP is the next potential occurring 90–80 ms (

Grosshirnläsionen Und Vestibulärer Nystagmus: Vergleichende elektronystagmographische Untersuchungen bei geschlossenen Augen and mit visueller Fixation

\bar x = {\text{87}}

Nystagmographie, Diagnose und Verlauf bei Brückenwinkeltumoren

, SD 34.2, SE 2.95) prior to the first action potential in the contracting muscle (EMG). It was found in 85% of our subjects. The PMP has at its maximum, mid-parietally, a mean amplitude of +1.7 μV (SD 1.6, SE 0.28). Like the BP, the PMP is bilateral and widespread in parietal and precentral leads of both sides and in the midline with a maximum at the anterior parietal region, despite the parietal skull being thicker than precentral. The short and the relatively constant onset time suggests that the PMP might reflect cortical activity (motor command) related to initiation of the tactually guided rapid finger movement under study.The MP starting 60–50 ms (

Nichtwahrnehmung Der Augenbewegungen und Corneo-Conjunctivale Entstehung Des Subjektiven Augenzuges Beim Vestibulären Nystagmus

\bar x = {\text{54}}

Psychologie und Psychiatrie der Kriegsgefangenschaft

, SD 19.4, SE 3.1) prior to first activity in the agonist EMG is the last potential to occur and is the only unilateral potential: its localisation is limited to the hand area of the motor cortex contralateral to the moving finger. In bipolar recordings, contralateral versus ipsilateral precentral or contralateral precentral versus vertex, it appears as a sharp additional negativity. This additional negativity averaged-1.3 μV (SD 0.64, SE 0.08). The MP reflects the motor cortical activity immediately preceding the movement.After movement onset, a complex potential is recorded, that is also seen with passive finger movement, largely representing a somatosensory (proprioceptive) evoked response. The possible meaning of the movement-related potentials is discussed in relation to a theory of central motor function.