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. Author manuscript; available in PMC: 2009 Nov 12.
Published in final edited form as: Eur J Neurosci. 2009 Apr 27;29(9):1761–1770. doi: 10.1111/j.1460-9568.2009.06720.x

Figure 4.

Figure 4

TMS during sleep triggers slow waves that resemble spontaneously occurring ones. (A, Upper) The signal recorded from a channel (Cz) located under the stimulator during two TMS-ON blocks over a background of spontaneous NREM sleep (single-subject data). Each TMS-ON block consisted of 40 stimuli at 0.8 Hz. The stimulation site (hot spot) is marked by a yellow cross on the cortical surface (the colored area represent the overall electric field induced by TMS). The red boxes (expanded below) include the slow waves triggered at the beginning and at the end of one block. Spontaneously occurring slow waves recorded from the same subject a few minutes later are depicted underneath. (B) TMS-evoked and spontaneous slow waves, recorded from all channels, were detected based on period-amplitude criteria and averaged on the negative peak. TMS-evoked and spontaneous slow waves had similar shape. (C) The average signal recorded from Cz was bandpass filtered (0.25–4 Hz) in the top trace. In the middle and bottom traces the corresponding single trials were filtered in the spindles frequency range (12–15 Hz) and rectified (rms). The positive wave of the TMS-evoked slow wave was associated with an increase in spindle amplitude.