Processing of Complex Auditory Patterns in Musicians and Nonmusicians

Bastiaan Boh,Claudia Lappe,Christo Pantev,Sibylle C Herholz,Jeffrey Krichmar

doi:10.1371/journal.pone.0021458

Abstract

In the present study we investigated the capacity of the memory store underlying the mismatch negativity (MMN) response in musicians and nonmusicians for complex tone patterns. While previous studies have focused either on the kind of information that can be encoded or on the decay of the memory trace over time, we studied capacity in terms of the length of tone sequences, i.e., the number of individual tones that can be fully encoded and maintained. By means of magnetoencephalography (MEG) we recorded MMN responses to deviant tones that could occur at any position of standard tone patterns composed of four, six or eight tones during passive, distracted listening. Whereas there was a reliable MMN response to deviant tones in the four-tone pattern in both musicians and nonmusicians, only some individuals showed MMN responses to the longer patterns. This finding of a reliable capacity of the short-term auditory store underlying the MMN response is in line with estimates of a three to five item capacity of the short-term memory trace from behavioural studies, although pitch and contour complexity covaried with sequence length, which might have led to an understatement of the reported capacity. Whereas there was a tendency for an enhancement of the pattern MMN in musicians compared to nonmusicians, a strong advantage for musicians could be shown in an accompanying behavioural task of detecting the deviants while attending to the stimuli for all pattern lengths, indicating that long-term musical training differentially affects the memory capacity of auditory short-term memory for complex tone patterns with and without attention. Also, a left-hemispheric lateralization of MMN responses in the six-tone pattern suggests that additional networks that help structuring the patterns in the temporal domain might be recruited for demanding auditory processing in the pitch domain.

Highlights

Listening or performing music engages the brain in many different ways involving learning, memory and emotions such as pleasure, causing music as a phenomenon to be a popular pastime
Please note that the values of average mismatch negativity (MMN) peak amplitudes do not match exactly in the source waveforms and in the bar plot, because individual peak values are represented in figure 4, and because both groups have been averaged for this figure, as justified by an absence of an interaction of group, hemisphere and condition
Capacity of the memory store Using a stimulation of repeated complex tone patterns of four, six or eight tones of unique frequencies, we investigated the capacity of the memory trace underlying the MMN response

Summary

Introduction

Listening or performing music engages the brain in many different ways involving learning, memory and emotions such as pleasure, causing music as a phenomenon to be a popular pastime. One important aspect of music processing is the ability to represent and categorize tone strings and recognize reoccurring patterns in the incoming information. This applies to music, but to auditory scene analysis in general, where pattern detection is an efficient way of reducing computation costs. Any competing sound streams with similar content will be attenuated during this process [6]. In this respect, it is important to realize that with each new incoming tone, the existing representation of regularity or of a pattern can either be expanded, or altered by discarding its first tone. Representations of regularities can be formed and maintained on different hierarchical levels of complexity simultaneously [7]

Methods

Results

Discussion

Conclusion