A Recurrent Connectionist Model of Melody Perception: An Exploration Using TRACX2.

Are similar, or even identical, mechanisms used in the computational modeling of speech segmentation, serial image processing, and music processing? We address this question by exploring how TRACX2, a recognition-based, recursive connectionist autoencoder model of chunking and sequence segmentation, which has successfully simulated speech and serial-image processing, might be applied to elementary melody perception. The model, a three-layer autoencoder that recognizes "chunks" of short sequences of intervals that have been frequently encountered on input, is trained on the tone intervals of melodically simple French children's songs. It dynamically incorporates the internal representations of these chunks into new input.

[Very early deflections of the visual evoked response (author's transl)].

The authors confirm the presence of very early deflection (before the 20th msec. after the flash). They probably have their origin under the cortex.

[Intensity of spontaneous activity and mean visual evoked response during calculation of variable mean. New technique for measuring retinocortical time (author's transl)].

Various statistical discrimination indices reveal deflections regarded as significant before the 20th ms after stimulation (probably equivalent to Bickford responses or subcortical activity) and between the 20th and 23rd ms (early fractions of MVER). The independence of signal and noise is discussed. Considerations concerning the calculation of retinocortical time are developed.

[Contribution towards the study of the average visual-evoked response; non-gaussian character of spontaneous electroencephalographic activity; non-independence of noise and signal; possible non-stationary character of evoked response (author's transl)].

The succession of amplitudes constituting spontaneous electroencephalographic activity cannot be regarded as a strictly normal distribution. Spontaneous activity and the evoked response are not independent. The signal (evoked response)is, in some cases, non-stationary.