Sensitivity to combinations of musical parameters: pitch with duration, and pitch pattern with durational pattern

Feature binding in auditory modality requires attention as indexed by mismatch negativity and N2b in an active discrimination task

Currently, there are two opposing views on feature binding in the auditory modality: according to behavioral studies, this process requires focused attention, whereas electrophysiological studies suggest that feature binding may be fully automatic and independent of attention. Here, we examined whether feature binding depends on higher-level attentional processes by manipulating the attentional focus. We used four auditory stimuli that differed in two features: pitch and location. Two rare deviants could be detected within a sequence of two frequent standards exclusively by feature conjunctions rather than by any single feature alone. Event-related potentials to auditory stimuli were analyzed for four conditions: selective attention to target auditory deviants, selective ignoring of nontarget auditory deviants, nonselective distributed attention to all stimuli within auditory modality, and selective attention diverted from auditory to visual modality. The negative difference (Nd) between event-related potentials to deviants and standards was measured within two time intervals, corresponding to mismatch negativity (100-200 ms) and N2b (200-300 ms). Only under the condition of selective attention to specific feature conjunctions, prominent Nd was observed in mismatch negativity as well in N2b time ranges, whereas no significant Nd was observed in other conditions. As Nd is considered a marker of deviance processing, our results support the view that deviance was not detected unless attention was focused on the stimuli, thus supporting the view that feature binding requires attention.

Distributed feature binding in the auditory modality: experimental evidence toward reconciliation of opposing views on the basis of mismatch negativity and behavioral measures

Current understanding of feature binding remains controversial. Studies involving mismatch negativity (MMN) measurement show a low level of binding, whereas behavioral experiments suggest a higher level. We examined the possibility that the two levels of feature binding coexist and may be shown within one experiment. The electroencephalogram was recorded while participants were engaged in an auditory two-alternative choice task, which was a combination of the oddball and the condensation tasks. Two types of deviant target stimuli were used - complex stimuli, which required feature conjunction to be identified, and simple stimuli, which differed from standard stimuli in a single feature. Two behavioral outcomes - correct responses and errors - were analyzed separately. Responses to complex stimuli were slower and less accurate than responses to simple stimuli. MMN was prominent and its amplitude was similar for both simple and complex stimuli, whereas the respective stimuli differed from standards in a single feature or two features respectively. Errors in response only to complex stimuli were associated with decreased MMN amplitude. P300 amplitude was greater for complex stimuli than for simple stimuli. Our data are compatible with the explanation that feature binding in auditory modality depends on two concurrent levels of processing. We speculate that the earlier level related to MMN generation is an essential and critical stage. Yet, a later analysis is also carried out, affecting P300 amplitude and response time. The current findings provide resolution to conflicting views on the nature of feature binding and show that feature binding is a distributed multilevel process.

Repetition suppression in auditory-motor regions to pitch and temporal structure in music

Music performance requires control of two sequential structures: the ordering of pitches and the temporal intervals between successive pitches. Whether pitch and temporal structures are processed as separate or integrated features remains unclear. A repetition suppression paradigm compared neural and behavioral correlates of mapping pitch sequences and temporal sequences to motor movements in music performance. Fourteen pianists listened to and performed novel melodies on an MR-compatible piano keyboard during fMRI scanning. The pitch or temporal patterns in the melodies either changed or repeated (remained the same) across consecutive trials. We expected decreased neural response to the patterns (pitch or temporal) that repeated across trials relative to patterns that changed. Pitch and temporal accuracy were high, and pitch accuracy improved when either pitch or temporal sequences repeated over trials. Repetition of either pitch or temporal sequences was associated with linear BOLD decrease in frontal-parietal brain regions including dorsal and ventral premotor cortex, pre-SMA, and superior parietal cortex. Pitch sequence repetition (in contrast to temporal sequence repetition) was associated with linear BOLD decrease in the intraparietal sulcus (IPS) while pianists listened to melodies they were about to perform. Decreased BOLD response in IPS also predicted increase in pitch accuracy only when pitch sequences repeated. Thus, behavioral performance and neural response in sensorimotor mapping networks were sensitive to both pitch and temporal structure, suggesting that pitch and temporal structure are largely integrated in auditory-motor transformations. IPS may be involved in transforming pitch sequences into spatial coordinates for accurate piano performance.

The effects of duration and frequency of occurrence of voiceless fricatives on listeners' perceptions of sound prolongations

The present study examined listeners' identification and rating of words in passages as stuttered when the duration and frequency of occurrence of sound prolongations were manipulated. Thirty-six participants listened to a 219-word passage containing voiceless fricatives digitally increased from their normal durations to 200, 300, and 420ms. Listeners heard one of three passages that contained 5%, 10% or 15% altered stimuli within the passage. In Condition 1, listeners identified words considered stuttered. In Condition 2, listeners rated specifically selected words in the passage relative to the extent they considered the words stuttered. The results showed that (1) both the duration and the frequency of occurrence of the altered phonemes within the paragraph length material had an impact on listeners' perception of words identified as a sound prolongation; (2) listeners gave significantly higher ratings in Condition 2 than Condition 1 when determining if a word was stuttered or produced fluently. The implications of these results are discussed.

LEARNING OUTCOMES

After reading this article, the reader will be able to: (1) Describe the past literature on listener perceptions of stuttering. (2) Differentiate between listener's perceptions of sound prolongations that are altered in duration and frequency of occurrence. (3) Describe how paragraph-length speech material compares to past research that has used isolated utterances.

Preattentive representation of feature conjunctions for concurrent spatially distributed auditory objects

The role of attention in conjoining features of an object has been a topic of much debate. Studies using the mismatch negativity (MMN), an index of detecting acoustic deviance, suggested that the conjunctions of auditory features are preattentively represented in the brain. These studies, however, used sequentially presented sounds and thus are not directly comparable with visual studies of feature integration. Therefore, the current study presented an array of spatially distributed sounds to determine whether the auditory features of concurrent sounds are correctly conjoined without focal attention directed to the sounds. Two types of sounds differing from each other in timbre and pitch were repeatedly presented together while subjects were engaged in a visual n-back working-memory task and ignored the sounds. Occasional reversals of the frequent pitch-timbre combinations elicited MMNs of a very similar amplitude and latency irrespective of the task load. This result suggested preattentive integration of auditory features. However, performance in a subsequent target-search task with the same stimuli indicated the occurrence of illusory conjunctions. The discrepancy between the results obtained with and without focal attention suggests that illusory conjunctions may occur during voluntary access to the preattentively encoded object representations.

The octave illusion revisited again

The octave illusion (D. Deutsch, 1974) occurs when 2 tones separated by an octave are alternated repeatedly, such that when the right ear receives the high tone, the left ear receives the low tone, and vice versa. Most subjects in the original study reported hearing a single tone that alternated from ear to ear, whose pitch also alternated from octave to octave, and D. Deutsch (1975a) proposed an explanation in terms of separate what and where auditory pathways. C. D. Chambers, J. B. Mattingley, and S. A. Moss (2002) argued that the perceived pitch difference generally corresponds more to a semitone and proposed an alternative explanation in terms of diplacusis. This article argues that Chambers et al. used problematic procedures and reports a new experiment on the octave illusion. The findings confirm that an octave difference is generally perceived, and they agree with the model of Deutsch (1975a) but are at variance with the diplacusis hypothesis.

Exploring the functional neuroanatomy of music performance, perception, and comprehension

This chapter highlights findings by my colleagues and me in four neuroimaging and neurological studies of music performance, perception, and comprehension. These investigations elucidate the neural subsystems supporting musical pitch, melody, harmony, rhythm, tempo, meter, and duration. In a positron emission tomography (PET) study of pianists, a memorized performance of a musical piece was contrasted with that of scales to localize brain areas specifically supporting music. A second PET study assayed brain areas subserving selectively the comprehension of harmony, melody, and rhythm. Musicians sight-read a score while detecting specific melodic, harmonic, or rhythmic errors in its heard performance. In a third PET study, musicians and nonmusicians discriminated pairs of rhythms with respect to pattern, tempo, meter, or duration. Data in these studies implicated the cerebellum in nonmotor, nonsomatic, sensory, or cognitive processing. In a fourth study, neurological patients with degeneration of the cerebellum were found to be impaired in fine discrimination of pitch. Overall, these data suggest that the neural systems underlying music are distributed throughout the left and right cerebral and cerebellar hemispheres, with different aspects of music processed by distinct neural circuits. Also discussed are key issues for interpreting the role in music of brain areas implicated in neuroimaging studies.

Illusory conjunctions of pitch and duration in unfamiliar tone sequences

In 3 experiments, the authors examined short-term memory for pitch and duration in unfamiliar tone sequences. Participants were presented a target sequence consisting of 2 tones (Experiment 1) or 7 tones (Experiments 2 and 3) and then a probe tone. Participants indicated whether the probe tone matched 1 of the target tones in both pitch and duration. Error rates were relatively low if the probe tone matched 1 of the target tones or if it differed from target tones in pitch, duration, or both. Error rates were remarkably high, however, if the probe tone combined the pitch of 1 target tone with the duration of a different target tone. The results suggest that illusory conjunctions of these dimensions frequently occur. A mathematical model is presented that accounts for the relative contribution of pitch errors, duration errors, and illusory conjunctions of pitch and duration.

Evidence for auditory feature integration with spatially distributed items

Recent auditory research using sequentially presented, spatially fixed tones has found evidence that, as in vision for simultaneous, spatially distributed objects, attention appears to be important for the integration of perceptual features that enable the identification of auditory events. The present investigation extended these findings to arrays of simultaneously presented, spatially distributed musical tones. In the primary tasks, listeners were required to search for specific cued conjunctions of values for the features of pitch and instrument timbre. In secondary tasks, listeners were required to search for a single cued value of either the pitch or the timbre feature. In the primary tasks, listeners made frequent errors in reporting the presence or absence of target conjunctions. Probability modeling, derived from the visual search literature, revealed that the error rates in the primary tasks reflected the relatively infrequent failure to correctly identify pitch or timbre features, plus the far more frequent illusory conjunction of separately presented pitch and timbre features. Estimates of illusory conjunction rate ranged from 23% to 40%. Thus, a process must exist in audition that integrates separately registered features. The implications of the results for the processing of isolated auditory features, as well as auditory events defined by conjunctions of features, are discussed.

Recognition of music in long-term memory: are melodic and temporal patterns equal partners?

The notion that the melody (i.e., pitch structure) of familiar music is more recognizable than its accompanying rhythm (i.e., temporal structure) was examined with the same set of nameable musical excerpts in three experiments. In Experiment 1, the excerpts were modified so as to keep either their original pitch variations, whereas durations were set to isochrony (melodic condition) or their original temporal pattern while played on a single constant pitch (rhythmic condition). The subjects, who were selected without regard to musical training, were found to name more tunes and to rate their feeling of knowing the musical excerpts far higher in the melodic condition than in the rhythmic condition. These results were replicated in Experiment 2, wherein the melodic and rhythmic patterns of the musical excerpts were interchanged to create chimeric mismatched tunes. The difference in saliency of the melodic pattern and the rhythmic pattern also emerged with a music-title-verification task in Experiment 3, hence discarding response selection as the main source of the discrepancy. The lesser effectiveness of rhythmic structure appears to be related to its lesser encoding distinctiveness relative to melodic structure. In general, rhythm was found to be a poor cue for the musical representations that are stored in long-term memory. Nevertheless, in all three experiments, the most effective cue for music identification involved the proper combination of pitches and durations. Therefore, the optimal code of access to long-term memory for music resides in a combination of rhythm and melody, of which the latter would be the most informative.