Noninvasive extraction of microsecond-scale dynamics from human motor cortex

Research output: Contribution to journalArticle


Research units

  • University of Helsinki


State-of-the-art noninvasive electromagnetic recording techniques allow observing neuronal dynamics down to the millisecond scale. Direct measurement of faster events has been limited to in vitro or invasive recordings. To overcome this limitation, we introduce a new paradigm for transcranial magnetic stimulation. We adjusted the stimulation waveform on the microsecond scale, by varying the duration between the positive and negative phase of the induced electric field, and studied corresponding changes in the elicited motor responses. The magnitude of the electric field needed for given motor-evoked potential amplitude decreased exponentially as a function of this duration with a time constant of 17 μs. Our indirect noninvasive measurement paradigm allows studying neuronal kinetics on the microsecond scale in vivo.


Original languageEnglish
Pages (from-to)2405-2411
JournalHuman Brain Mapping
Publication statusPublished - 2018
MoE publication typeA1 Journal article-refereed

    Research areas

  • Electromyography, Ion-channel dynamics, Motor-evoked potential, Primary motor cortex, Pulse waveform, Transcranial magnetic stimulation, Voltage-gated sodium channels

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ID: 18203347