Abstract
We explored the aftereffects of two premotor 1 Hz rTMS sessions on motor cortex excitability in healthy humans. In experiment 1, 11 healthy right-handed volunteers received 20-min submotor threshold 1 Hz rTMS trains over the left premotor cortex on 2 consecutive days. Left motor cortex excitability was determined at baseline, immediately after, 30, 60, 120 min, and 24 h after each rTMS session. We measured motor thresholds, amplitudes of motor-evoked potentials, silent periods, and paired-pulse excitability at interstimulus intervals (ISI) of 3-7, 10, and 15 ms. In experiment 2, 5 volunteers received two identical rTMS trains on Days 1 and 7. Measurements were carried out on Day 1 (first rTMS train), Day 2, and Day 7 (second rTMS train). In experiment 1 there was a selective increase of paired pulse facilitation at an ISI of 7 ms after rTMS lasting for less than 30 min on Day 1. This effect was also present after rTMS on Day 2. However, it persisted for at least 2 h. In experiment 2 the same extra facilitation was induced by rTMS on Days 1 and 7 but not on Day 2. It lasted for less than 30 min on both Day 1 and Day 7. We conclude that 1 Hz premotor rTMS leads to cumulative plastic changes of intrinsic motor cortex excitability when repeated within 24 h but not after 1 week, implying the formation of memory after the first rTMS train lasting more than a day but less than a week.
| Original language | English |
|---|---|
| Journal | NeuroImage |
| Volume | 20 |
| Issue number | 1 |
| Pages (from-to) | 550-560 |
| Number of pages | 11 |
| ISSN | 1053-8119 |
| DOIs | |
| Publication status | Published - 01.09.2003 |
Funding
Statistical advice by Michael Bubenheim, Department for Mathematics, Hamburg University Hospital, is gratefully acknowledged. A. Münchau was supported by the Volkswagenstiftung. The study was also supported by the Deutsche Forschungsgemeinschaft (WE 1352/13-1), the Bundesministerium für Bildung und Forschung (GFGO 0 123 7301 - 01GO 0105), and the European Union (QLK6 CT 1999 02140). We wish to thank the reviewers of this paper for their thoughtful and constructive criticism. Experiment 2 was designed on the basis of their suggestions.
