The

subjects were seated in a chair in a magnetically shielded room and listened to the group sequence and the random sequence in separate sessions by using a magnetoencephalography (MEG)-compatible earphone connected with silicon air tubes. Before the experiment, we asked the subjects whether the tones could be heard from both ears with the same loudness and all of them reported that they could be heard correctly. The group sequence was always presented in a session after the random sequence in order to avoid the interference of grouping effect on the random sequence. While the subjects were listening, they were instructed to press a button by their right index finger if they noticed the omission of a tone. Because the total length of the group sequence was long (over 20 min), we divided this into two sessions. Thus, the experiment consisted of one session of random see more sequence (8 min) and two sessions of group sequence (12 min × 2). After each session, in order to check the subjects’ arousal level and fatigue, we asked the subjects whether they felt sleepy or wanted to have

a short break. If the subjects felt tired, Oligomycin A cost they were allowed to have a short break. Including the short breaks, the total time of the measurement was about 35–40 min. The experimental design was a two-way mixed design with musical experience (musicians or non-musicians) and omission (random, within-group or between-group). At the end of the experiment, we asked the subjects whether the stimuli in the group sequence had been recognised as the LLS pattern and all subjects reported noticing this pattern. The auditory evoked magnetic fields were recorded with a 306-channel whole-head MEG system (Vectorview, Elekta Neuromag Oy, Finland), which contained 102 sensor triplets consisting of two planar gradiometers and one magnetometer each. The exact head position with respect to the sensors was determined by measuring signals from four indicator coils attached

to the scalp. In addition, three head landmarks (the nasion and bilateral pre-auricular points) and the subject’s head shape were recorded with a spatial digitiser (Polhemus Inc., Colchester, USA) before Cyclin-dependent kinase 3 the experiment. These data were used for co-registration with the individual structural magnetic resonance imaging data obtained using a 0.2 T magnetic resonance scanner (Signa profile, GE Health Care, Waukesha, USA). The MEG data were recorded with a bandpass filter of 0.1–200.0 Hz and a sampling rate of 600.0 Hz. To reduce external noise, we used spatio-temporal signal space separation methods (MaxFilter, Elekta Neuromag Oy) with a correlation window of 900 s, which covered the whole length of each session, and a correlation limit of 0.980. The acquired data were low-pass filtered using a fifth-order Butterworth zero-phase filter with a cut-off frequency of 40 Hz.