TY - GEN
T1 - Putting the tritone paradox into context
T2 - Insights from neural population decoding and human psychophysics
AU - Englitz, Bernhard
AU - Akram, S.
AU - David, S. V.
AU - Chambers, C.
AU - Pressnitzer, Daniel
AU - Depireux, D.
AU - Fritz, J. B.
AU - Shamma, Shihab A.
PY - 2013
Y1 - 2013
N2 - The context in which a stimulus occurs can influence its perception. We study contextual effects in audition using the tritone paradox, where a pair of complex (Shepard) tones separated by half an octave can be perceived as ascending or descending. While ambiguous in isolation, they are heard with a clear upward or downward change in pitch, when preceded by spectrally matched biasing sequences. We presented these biased Shepard pairs to awake ferrets and obtained neuronal responses from primary auditory cortex. Using dimensionality reduction from the neural population response, we decode the perceived pitch for each tone. The bias sequence is found to reliably shift the perceived pitch of the tones away from its central frequency. Using human psychophysics, we provide evidence that this shift in pitch is present in active human perception as well. These results are incompatible with the standard absolute distance decoder for Shepard tones, which would have predicted the bias to attract the tones. We propose a relative decoder that takes the stimulus history into account and is consistent with the present and other data sets.
AB - The context in which a stimulus occurs can influence its perception. We study contextual effects in audition using the tritone paradox, where a pair of complex (Shepard) tones separated by half an octave can be perceived as ascending or descending. While ambiguous in isolation, they are heard with a clear upward or downward change in pitch, when preceded by spectrally matched biasing sequences. We presented these biased Shepard pairs to awake ferrets and obtained neuronal responses from primary auditory cortex. Using dimensionality reduction from the neural population response, we decode the perceived pitch for each tone. The bias sequence is found to reliably shift the perceived pitch of the tones away from its central frequency. Using human psychophysics, we provide evidence that this shift in pitch is present in active human perception as well. These results are incompatible with the standard absolute distance decoder for Shepard tones, which would have predicted the bias to attract the tones. We propose a relative decoder that takes the stimulus history into account and is consistent with the present and other data sets.
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U2 - 10.1007/978-1-4614-1590-9_18
DO - 10.1007/978-1-4614-1590-9_18
M3 - Conference contribution
C2 - 23716220
AN - SCOPUS:84884691197
SN - 9781461415893
T3 - Advances in Experimental Medicine and Biology
SP - 157
EP - 164
BT - Basic Aspects of Hearing
PB - Springer Science and Business Media, LLC
ER -