Evoked magnetoencephalographic responses to omission of a tone in a musical scale
Excerpts from Beethoven’s piano concerto No. 5 and Bernstein’s “Somewhere.”
Examples of scales used in the experiments. (a) complete C-major scale, (b) Prolong-Before-Skip-E: E is skipped and the preceding D is prolonged, (c) Repeat-BS-E: the preceding D is repeated, (d) Repeat-After-Skip-E: F which follows the omitted E is repeated, (e) Rhythm pattern 1, (f) Rhythm pattern 2. The capital letters on the top are the tone names of the notes in (a) and (b).
Modified RMS traces for mismatch fields of the participants S7 (left) and S11 (right) in response to omission of 6 tones (designated by 6 types of lines) in Prolong-Before-Skip experiments. The time window of 0.4 s corresponds to the periods for the target and the next tones; the first 0.2 s period actually corresponds to the second half of the prolonged tone.
, the magnitudes of mismatch responses in the Prolong-Before-Skip experiments for the 6 target tones and all participants. Each bar shows the magnitude for each subject and tone designated by the letter in each vertical section. The magnitude is the peak RMS amplitude of the difference between the standard and deviant responses and is defined by Eq. (1).
The grand averages of the 13 participants for all the omitted tones shown by the modified RMS waveforms in Prolong-BS experiments. In (a) the horizontal axis is the time after the onset of the scales and in (b) only the periods corresponding to the target tone and the tone following it are extracted as in Fig. 3.
Modified RMS traces for mismatch fields of the participants S12 (left) and S20 (right) in response to omission of 6 tones in Repeat-Before-Skip experiments.
, the magnitude of mismatch response in the Repeat-Before-Skip experiments for each target tone in each subject. The asterisk shows a significant () and the cross a moderate () differences.
The grand averages of 12 participants in Repeat-Before-Skip experiments.
Modified RMS traces for mismatch fields of the participants S4 (left) and S15 (right) in response to omission of 6 tones in RAS experiments.
, the magnitude of mismatch response for each target tone and participant in the Repeat-After-Skip experiments. The crosses show moderate differences ().
Grand averages of the mismatch fields of the all participating in Repeat-After-Skip experiments.
RMS waveforms of standard (solid lines) and deviant (dotted lines) responses in various situations. (a) S15, Repeat-Before-Skip B (RBS-B); (b) S15, Reverse-RBS-A; (c) S4, RRBS-E.
The results of S15 (left) and S22 (right) in Reverse-RBS (reverse oddball) experiments shown by the modified RMS [Eq. (2)] with replaced with its negative. See text.
Left panel shows the activity difference (Eq. (1)) for each target tone and subject in the Reverse-RBS experiments. The negative values indicate larger responses to the standard stimuli which were incomplete scales in these experiments. Right panel shows the mismatch magnitude [Eq. (1)]. There was a significant () difference between the means of for D and B omissions.
Grand averages of all participating in Reverse-RBS experiments. (a) The difference ; (b) the RMS of the difference ; and (c) the average as in Fig. 13.
The results of S34 (left) and S36 (right) in RTM experiments.
, the magnitude of the mismatch field defined by Eq. (1) for each rhythm pattern and subject in the Rhythm experiment. The left panel shows the results for the period 0.08–0.28 s and the right for the period: 0.28–0.48 s.
Grand averages of all participating in RTM experiments.
(Left) The significance probability (p-value) for [Eq. (1)], the difference between the RMS peaks of the deviant and standard responses. (Right) The average mismatch magnitude for each tone omission in each experiment.
Examples illustrating the concluding points 2 – 5. The arrows indicate where the cortex responds vividly. The thinner arrows in (d) and (f) indicate somewhat smaller or ambiguous responses compared to (c) and (e), respectively. In (e) and (f), the scale has been changed to even shorter phrases.
Averages and SDs of the latencies [ms] of the peaks of RMS of mismatch responses for all the omission tones in Prolong-Before-Skip and Repeat-BS experiments. p-values from the t-tests for PBS and RBS pairs for all the omitted tones are also shown.
Averages and SDs of the latencies [ms] of the peaks of the modified RMS for all the omission tones in Prolong-Before-Skip and Repeat-BS experiments. p-values from the t-tests for PBS and RBS pairs for all the omitted tones are also shown.
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