Patel, A.D. & Balaban, E. "Temporal patterns of human cortical activity reflect tone sequence structure"
Nature 404:80-84 (2000).
(paper - Adobe Acrobat pdf file)
(news & views article - Adobe Acrobat pdf file)
(supplementary information - MS Word 97 document)

These examples represent a complete set of stimuli heard by one subject. Each subject heard a unique set of stimuli (with the exception of the scale patterns, which were identical across subjects).

All tone sequences are in the key of A (central tone is A4 = 440 Hz), and are bounded by A3 (220 Hz) and A5 (880 Hz). Seven Western European diatonic modes are represented in each condition: ionian ("major scale"), dorian, phrygian, lydian, mixolydian, aeolian ("minor scale") and locrian.

Random tone sequences have unpredictable variation from one pitch to the next. Scales have deterministic stepwise pitch patterns. The "one over f" and "one over f squared" sequences are intermediate. "One over f" patterns have a fair degree of unpredictable variation with some long-term pitch trends. "One over f squared" patterns are much stronger in long-term pitch trends, but still retain some unpredictable smaller variations. Statistically, the "one over f squared" patterns more closely resemble musical melody (they lack the liveliness of actual melodies, but share the sense of simultaneous large-scale pattern and small scale variation).

Each .wav file is approximately 1 minute long (1.3 MB).

We suggest listening to the sequences with good-quality headphones or speakers, as they can sound distorted when played over built-in computer speakers.

random_ionian.wav
random_dorian.wav
random_phrygian.wav
random_lydian.wav
random_mixolydian.wav
random_aeolian.wav
random_locrian.wav

one_over_f_ionian.wav
one_over_f_dorian.wav
one_over_f_phrygian.wav
one_over_f_lydian.wav
one_over_f_mixolydian.wav
one_over_f_aeolian.wav
one_over_f_locrian.wav

one_over_f_squared_ionian.wav
one_over_f_squared_dorian.wav
one_over_f_squared_phrygian.wav
one_over_f_squared_lydian.wav
one_over_f_squared_mixolydian.wav
one_over_f_squared_aeolian.wav
one_over_f_squared_locrian.wav

scales_ionian.wav
scales_dorian.wav
scales_phrygian.wav
scales_lydian.wav
scales_mixolydian.wav
scales_aeolian.wav
scales_locrian.wav

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