Related Experiment Video
Updated: Aug 18, 2026

Quantifying Infra-slow Dynamics of Spectral Power and Heart Rate in Sleeping Mice
Published on: August 2, 2017
The vanishing point of the mismatch negativity at sleep onset
1Faculty of Integrated Arts and Sciences, Hiroshima University, 1-7-1 Kagamiyama, 739-8521, Higashi-Hiroshima, Japan.
Objective:
To determine when the mismatch negativity (MMN) disappears at sleep onset, event-related potentials (ERPs) were recorded continuously from wakefulness to sleep.
Methods:
Ten healthy young students were told to fall asleep ignoring the tones presented through a loudspeaker above their head. Standard (1000 Hz, P=0.90), high deviant (1200 Hz, P=0.05), and low deviant (1050 Hz, P=0.05) tones were presented in a quasirandom order with a fixed stimulus onset asynchrony of 500 ms. ERP waveforms were obtained separately for 5 successive stages characterized by typical electroencephalographic (EEG) patterns of the sleep onset period. The EEG staging was made manually with very short (5 s) scoring epochs.
Results:
The MMN appeared in wakefulness and in the early phase of stage 1 sleep (EEG stage II) but disappeared when low-voltage theta waves emerged after alpha flattening (EEG stage III). Instead, P240 and N360 developed particularly for high deviant tones.
Conclusions:
Concurrently with the disappearance of alpha waves, the automatic change detection system in wakefulness seems to stop operating and a different sleep-specific system becomes dominant.

