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Cochlear implants (CIs) are biomedical devices that provide sound to people with severe-to-profound hearing loss by direct electrical stimulation of auditory neurons in the cochlea. Despite the remarkable achievements with respect to speech perception in quiet environments, music perception with CIs remains generally poor due to the degradation of auditory input. Prior studies have shown that both pitch perception and timbre discrimination are poor in CI users, whereas the performance on rhythmic tasks is nearly equivalent to normal hearing participants. There are several caveats, however, to this generalization regarding rhythm processing for CI users. The purpose of this article is to summarize the literature on rhythmic perception for CI users while highlighting important limitations within these studies. We will also identify areas for future research and development of CI-mediated music processing. It is likely that rhythm processing will continue to advance as our understanding of electrical current delivery to the auditory nerve improves., (© 2019 New York Academy of Sciences.)

Many domains of human behavior are based on multisensory representations. Knowledge about the principles of multisensory integration is useful to configure real-time movement information for the online support of perceptuomotor processes (motor perception, control, and learning). A powerful method for generating real-time information is movement sonification. Remarkable evidence exists on movement-acoustic real-time information being effective in behavioral domains (music training, motor rehabilitation, sports). Here, we investigate whether and how biological motion perception can be enhanced, substituted, or modulated by kinematic sonification, with a focus on pitch coding. We work with gross motor cyclic movements and investigate the effectiveness of pitch scaling and consistent transposition on audiovisual motor perception accuracy (Experiment A). Beyond that, a new kind of audiovisual stimulus with inconsistent pitch transposition is used to produce a directed modulation of the integrated audiovisual percept (Experiment B). Results from Experiment A indicate pitch being powerful for mediating kinematic information to enhance motor perception and substituting information between perceptual modalities, even exceeding visual performance. Beyond these findings, results from Experiment B indicate that visual estimations of movement velocity can be enhanced or reduced auditorily. Movement sonification used for reshaping intermodal adjustments should be a powerful new tool for subconsciously shaping human movement patterns in the future., (© 2018 New York Academy of Sciences.)

The study of musical ability has gained considerable traction across disciplines in recent years. In comparison, less effort has been invested in the development of sound measures of musical ability. To redress this gap, we conducted four studies to empirically validate two brief measures derived from the Profile of Music Perception Skills (PROMS)-an exceptionally inclusive battery of musical abilities that takes about 1 h to complete. In the Short-PROMS, test duration was reduced to less than half an hour by substantially reducing the number of trials per subtest. In the Mini-PROMS, the number of subtests was reduced to four, resulting in a battery that takes 15 min to complete. Both measures exhibited good internal consistency and retest reliability. Support for convergent, discriminant, and criterion validity was found across the studies. Additional strengths of the new instruments include their suitability for online administration and a feature called Modular PROMS, which offers researchers the possibility to request customized batteries that may include any combination of the subtests. The role of refining objective assessment instruments in research on music and the mind is discussed., (© 2017 The Authors. Annals of the New York Academy of Sciences published by Wiley Periodicals Inc. on behalf of The New York Academy of Sciences.)

Whereas much of research in music and neuroscience is aimed at understanding the mechanisms by which the human brain facilitates music, emerging interest in the neuromusic community aims to translate basic music research into clinical and educational applications. In the present paper, we explore the problems of poor pitch perception and production from both neurological and developmental/educational perspectives. We begin by reviewing previous and novel findings on the neural regulation of pitch perception and production. We then discuss issues in measuring singing accuracy consistently between the laboratory and educational settings. We review the Seattle Singing Accuracy Protocol--a new assessment tool that we hope can be adopted by cognitive psychologists as well as music educators-and we conclude with some suggestions that the present interdisciplinary approach might offer for future research., (© 2014 New York Academy of Sciences.)

Singing in one's mind or forming expectations about upcoming notes both require that mental images of one or more pitches will be generated. As with other musical abilities, the acuity with which such images are formed might be expected to vary across individuals and may depend on musical training. Results from several behavioral tasks involving intonation judgments indicate that multiple memory systems contribute to the formation of accurate mental images for pitch, and that the functionality of each is affected by musical training. Electrophysiological measures indicate that the ability to form accurate mental images is associated with greater engagement of auditory areas and associated error-detection circuitry when listeners imagine ascending scales and make intonation judgments about target notes. A view of auditory mental images is espoused in which unified mental image representations are distributed across multiple brain areas. Each brain area helps shape the acuity of the unified representation based on current behavioral demands and past experience., (© 2012 New York Academy of Sciences.)

Even expert musicians make errors occasionally, and overt responses that are correct may be accompanied by partial-error behavior that can be indicative of online error detection processes. We compare pianists' production of correct pitches, pitch errors, and partial errors (correct pitches with incorrect force or duration) by examining events prior to errors. Errors tended to be produced with slower durations and softer intensities (associated with force reduction) than correct events. In addition, pre-error events tended to have durations and intensities that fell between those of errors and correct responses, presumably due to response competition with upcoming errors that resulted in partial-error outcomes. These findings support the inference that partial information about upcoming (planned) sequence events is used to guide current responses, consistent with cascade models of activation during sequence production., (© 2012 New York Academy of Sciences.)

Recent research suggests that musical training enhances the neural encoding of speech. Why would musical training have this effect? The OPERA hypothesis proposes an answer on the basis of the idea that musical training demands greater precision in certain aspects of auditory processing than does ordinary speech perception. This paper presents two assumptions underlying this idea, as well as two clarifications, and suggests directions for future research., (© 2012 New York Academy of Sciences.)

This study examines the additivity of the Mismatch Negativity (MMN) as an index of the early interactions between vowels and pitch when sung. Event-related potentials (ERPs) were recorded while participants were presented with sung vowels. Sixteen percent of stimuli deviated in pitch only, in vowel only, or in both pitch and vowel. All three kinds of deviants elicited an MMN of similar amplitude. The MMNs to vowel and pitch deviants did not show significant additivity. This suggests that vowel and pitch are processed by shared neural substrates at the preattentive level.

In the neuroscience of music, musicians have traditionally been treated as a unified group, as if the demands set by their musical activities would be more or less equal in terms of perceptual, cognitive, and motor functions. However, obviously, their musical preferences differentiate them to a higher degree, for instance, in terms of the instrument they choose and the music genre they are mostly engaged with as well as their practicing style. This diversity in musicians' profiles has been recently taken into account in several empirical endeavors. The present contribution will review the evidence available about the various neurocognitive profiles these different kinds of musicians display.

Twenty amusic and 20 control speakers of French were presented with pairs of Mandarin lexical tones to discriminate as same or different. Results revealed that even if the amusic group performed significantly below the control group, the scores of the two groups largely overlapped, with only 15% of the amusic group performing outside the normal variations. Thus, the findings suggest a modest transfer of deficit between music and speech, which in turn calls for further work in order to identify the nature of the mediating factors.

Research and outcomes with cochlear implants (CIs) have revealed a dichotomy in the cues necessary for speech and music recognition. CI devices typically transmit 16-22 spectral channels, each modulated slowly in time. This coarse representation provides enough information to support speech understanding in quiet and rhythmic perception in music, but not enough to support speech understanding in noise or melody recognition. Melody recognition requires some capacity for complex pitch perception, which in turn depends strongly on access to spectral fine structure cues. Thus, temporal envelope cues are adequate for speech perception under optimal listening conditions, while spectral fine structure cues are needed for music perception. In this paper, we present recent experiments that directly measure CI users' melodic pitch perception using a melodic contour identification (MCI) task. While normal-hearing (NH) listeners' performance was consistently high across experiments, MCI performance was highly variable across CI users. CI users' MCI performance was significantly affected by instrument timbre, as well as by the presence of a competing instrument. In general, CI users had great difficulty extracting melodic pitch from complex stimuli. However, musically experienced CI users often performed as well as NH listeners, and MCI training in less-experienced subjects greatly improved performance. With fixed constraints on spectral resolution, such as occurs with hearing loss or an auditory prosthesis, training and experience can provide considerable improvements in music perception and appreciation.

Speech and music are highly complex signals that have many shared acoustic features. Pitch, Timbre, and Timing can be used as overarching perceptual categories for describing these shared properties. The acoustic cues contributing to these percepts also have distinct subcortical representations which can be selectively enhanced or degraded in different populations. Musically trained subjects are found to have enhanced subcortical representations of pitch, timbre, and timing. The effects of musical experience on subcortical auditory processing are pervasive and extend beyond music to the domains of language and emotion. The sensory malleability of the neural encoding of pitch, timbre, and timing can be affected by lifelong experience and short-term training. This conceptual framework and supporting data can be applied to consider sensory learning of speech and music through a hearing aid or cochlear implant.

In this study we examined the effect of reducing linguistic information on singing proficiency in occasional singers. Thirty-nine occasional singers were asked to sing from memory and to imitate three familiar melodies with lyrics and on the syllable /la/. Performances were analyzed with an acoustically based method yielding objective measures of pitch and temporal accuracy. Results obtained in production and imitation tasks revealed increased accuracy (e.g., fewer pitch interval errors and contour errors) when occasional singers produced melodies on a syllable as compared to singing with lyrics. This effect may be the result of reduced memory load and/or motor entrainment.

Musical ensemble performance requires precise coordination of action. To play in synchrony, ensemble musicians presumably anticipate the sounds that will be produced by their co-performers. These predictions may be based on auditory images in working memory. This study examined the contribution of auditory imagery abilities to sensorimotor synchronization (SMS) in 20 musicians. The acuity of single-tone pitch images was measured by an adjustment method and by adaptive threshold estimation. Different types of finger tapping tasks were administered to assess SMS. Auditory imagery and SMS abilities were found to be positively correlated with one another and with musical experience.

Absolute pitch (AP) is a rare skill, historically defined as the ability to name notes. Until now, methodologic limitations made it impossible to directly test the extent to which the development of AP depends on musical training. Using a new paradigm, we tested children with minimal musical experience. Although most children performed poorly, two performed comparably to adult possessors of AP. Follow-up testing showed that the performance of both children progressed to that of "classic" AP. These data support the theory that AP can result from differences in the encoding of stimulus frequency that are independent of musical experience.

We examined adults' and 6-month-old infants' event-related potentials in response to occasional changes (deviants) in a 4-note melody presented at different pitch levels from trial to trial. In both groups, responses to standard and deviant stimuli differed significantly; however, adults produced a typical mismatch negativity (MMN), whereas 6-month-old infants exhibited a slow positive wave. We conclude that 6-month-old infants, like adults, encode melodic information in terms of relative pitch distances, but that the underlying cortical activity differs significantly from that of adults.

We examined memory for pitch in congenital amusia in two tasks. In one task, we varied the pitch distance between the target and comparison tone from 4 to 9 semitones and inserted either a silence or 6 interpolated tones between the tones to be compared. In a second task, we manipulated the number of pitches to be retained in sequences of length 1, 3, or 5. Amusics' sensitivity to pitch distance was exacerbated by the presence of interpolated tones, and amusics' performance was more strongly affected by the number of pitches to maintain in memory than controls. A pitch perception deficit could not account for the pitch memory deficit of amusics.

The arcuate fasciculus (AF) is a bundle of white matter traditionally thought to be responsible for language function. However, its role in music is not known. Here we investigate the connectivity of the AF using diffusion tensor imaging (DTI) and show that musically tone-deaf individuals, who show impairments in pitch discrimination, have reduced connectivity in the AF relative to musically normal-functioning control subjects. Results were robust to variations in imaging parameters and emphasize the importance of brain connectivity in para-linguistic processes, such as music.

One of the most studied effects of verbal working memory (WM) is the influence of the length of the words that compose the list to be remembered. This work aims to investigate the nature of musical WM by replicating the word length effect in the musical domain. Length and rate of presentation were manipulated in a recognition task of tone sequences. Results showed significant effects for both factors (length and presentation rate) as well as their interaction, suggesting the existence of different strategies (e.g., chunking and rehearsal) for the immediate memory of musical information, depending upon the length of the sequences.

We study vibrato as the more ubiquitous manifestation of a nonstationary tone that can evoke a single overall pitch. Some recent results using nonsymmetrical vibrato tones suggest that the perceived pitch could be governed by some stability-sensitive mechanism. For nonstationary sounds the adequate tools are time-frequency representations (TFRs). We show that a recently proposed TFR could be the simplest framework to explain this hypothetical stability-sensitive mechanism. We propose a one-parameter model within this framework that is able to predict previously reported results and we present new results obtained from psychophysical experiments performed in our laboratory.

Acoustic short-term memory (ASTM) refers to the temporary retention of acoustic information. In the present study, we investigated the neural correlates of ASTM for pitch using magnetoencephalography (MEG) and functional magnetic resonance imaging (fMRI). Both MEG and fMRI analyses revealed brain activations that varied with memory load in the vicinity of secondary auditory cortex (Brodmann's area, BA22) and superior parietal cortex (BA5/7), while analyses specific to MEG data revealed load-related activations in the frontal cortex (BA9/10).

Cochlear implants (CIs) provide impressive speech perception for persons with severe hearing loss, but many CI recipients fail in perceiving speech prosody and music. Successful rehabilitation depends on cortical plasticity in the brain and postoperative measures. The present study evaluates the behavioral and neurologic effects of musical ear training on CI users' speech and music perception. The goal is to find and work out musical methods to improve CI users' auditory capabilities and, in a longer perspective, provide an efficient strategy for improving speech understanding for both adults and children with CIs.

We present three experiments that show a clear influence of pitch on reaching movements. The first experiment shows that when there are incompatibilities between the spatial representations of target coordinates and perceived pitches, response times are longer than when spatial representations are congruous. The second experiment shows that pitch can influence motor responses, biasing their direction. The third experiment shows that in the absence of any other spatial cues, tones are assigned spatial coordinates based on frequency. Our results suggest that pitch may indeed have inherent spatial properties, and that these properties may affect movement planning and execution.

Morphologic measures have long been used to determine the patho-anatomical signature of different neurologic disorders. However, these measures can also be used to determine effects of specific learning tasks and quantifiable human abilities on cerebral structure. Musicians provide interesting opportunities for this type of analysis as their various skills, such as rhythmic ability and pitch and harmony discrimination (acquired through years of practicing and playing) can be quantified and compared using distinct morphologic analyses. Here, we review magnetic resonance imaging-based morphologic analyses in the music and neuroscience literature and provide some results from our own analysis of rhythmic ability in a cohort of musicians.

Congenital amusia is a lifelong disorder affecting the processing of pitch. This pitch deficit can be traced down to abnormal brain responses elicited by pitch changes smaller than a semitone in conditions requiring attention. Here, we use the mismatch negativity (MMN) to investigate pre-attentive pitch change detection in 10 amusics and eight matched controls. Results indicate similar MMN in amusics and controls, even for an eighth of a tone change, revealing that the amusic brain can process small pitch changes at a pre-attentive level. Thus, the pitch deficit in congenital amusia may be related to a problem of perceptual awareness.

Infants are often presented with input in which there are multiple related regularities, as is the case in musical input with both melodic and lyrical structure. Adult learners often learn more easily from complex input containing multiple correlated regularities than from simplified input. Do infants also capitalize on complexity, or instead do they benefit from simplified input? In this series of experiments, infants were presented with music in which melodic and lyrical structure predicted each other, or in which only one type of regularity was presented in isolation (melodies alone, or lyrics presented with no melody). Infants learned lyrics more easily when they were paired with a melody than when they were presented alone; similarly, they learned melodies more easily when they were paired with lyrics than when they were presented alone. There are several potential mechanisms that could explain how infants' learning is facilitated by complex input, suggesting important implications for learning in infants' natural environments.

The ability to perceive sounds and correctly categorize them within a scale is the result of the interaction between inherited capabilities and acquired rules. If a subject listens to a melody, occasional and unexpected endings of the melody typically evoke characteristic auditory evoked responses in the latency range of 300-400 ms (P300). Also, earlier stages of auditory information processing have been exhaustively investigated by means of mismatch negativity (MMN), a deflection that occurs in the auditory evoked response at a latency of about 200 ms, whenever a deviance is randomly inserted in a series of otherwise equal stimuli. Conceivably, perceptual deviations could also be detected against expectancies that are based on abstract rules; introspective experience suggests that such deviations may also elicit fast intuitive responses that typically initiate processes of analytical reasoning for confirmation. In music, the physical features of the stimulus are, in fact, always changing, because the melodic contour consists of a series of notes with different pitch characteristics. In such a condition, a typical mismatch negativity would not be evoked on the basis of physical deviance, but rather of criteria involving the musical contour of the stimulus. In this study, 20 healthy subjects (10 nonmusicians and 10 musicians) underwent auditory stimulation (tone, chord, chord sequence, Mozart and Bach melodies) and both electrical and magnetic recordings. Clear N1 was recorded for all paradigms, in all subjects; MMN and P300 were also recorded, and their amplitudes and latencies were significantly correlated with the musicality score and with the paradigm's difficulty.

Harmony and tonality are two of the most difficult elements for young children to perceive and manipulate and are seldom taught in the schools until the end of early childhood. Children's gradual harmonic and tonal development has been attributed to their cumulative exposure to Western tonal music and their increasing experiential knowledge of its rules and principles. Two questions that are relevant to this problem are: (1) Can focused and systematic teaching accelerate the learning of the harmonic/tonal principles that seem to occur in an implicit way throughout childhood? (2) Are there cognitive constraints that make it difficult for young children to perceive and/or manipulate certain harmonic and tonal principles? A series of studies specifically addressed the first question and suggested some possible answers to the second one. Results showed that harmonic instruction has limited effects on children's perception of harmony and indicated that the drastic improvement in the perception of implied harmony noted approximately at age 9 is due to development rather than instruction. I propose that young children's difficulty in perceiving implied harmony stems from their attention behaviors. Older children have less memory constraints and more strategies to direct their attention to the relevant cues of the stimulus. Younger children focus their attention on the melody, if present in the stimulus, and specifically on its concrete elements such as rhythm, pitch, and contour rather than its abstract elements such as harmony and key. The inference of the abstract harmonic organization of a melody required in the perception of implied harmony is thus an elusive task for the young child.

This work addresses the brain basis for the analysis of pitch and pitch patterns required for normal musical perception. Recent functional imaging experiments are consistent with a hierarchical scheme for the analysis of pitch. Mechanisms in the ascending auditory pathway to the primary auditory cortex allow the representation of the spectral and temporal features of individual notes required for the perception of their pitch. Converging experiments where pitch strength is manipulated in different ways suggest that there may be a "pitch center" in the lateral part of Heschl's gyrus, adjacent to the primary auditory area. The suggestion is that there is a representation in this area that correlates with the perception of pitch rather than a simple mapping of physical stimulus characteristics. The analysis of patterns of pitch such as melodies, as opposed to the pitch of individual notes, involves much more distributed processing in the superior temporal lobes and frontal lobes. Involvement of the frontal lobe in pitch pattern analysis may in part reflect whether subjects analyze the pitch patterns in order to carry out an output task.

Brain activation patterns in a group of musicians and a group of nonmusicians (matched in performance score to the musician group) were compared during a pitch memory task using a sparse-temporal sampling functional magnetic resonance imaging experiment. Both groups showed bilateral activaton (left more than right) of the superior temporal gyrus, supramarginal gyrus, posterior middle and inferior frontal gyrus, and superior parietal lobe. Musicians showed greater right posterior temporal and supramarginal activation, whereas nonmusicians had greater activation of the left secondary auditory cortex.

In two experiments, musically trained and untrained adults were tested on their ability to match spoken utterances with their tonal analogues (tone sequences that retained the pitch and temporal patterns of the utterances). In both cases, musical training was associated with superior performance, indicating an enhanced ability to extract prosodic information from spoken phrases.

The perceptual pitch dimensions of chroma and height have distinct representations in the human brain: chroma is represented in cortical areas anterior to primary auditory cortex, whereas height is represented posterior to primary auditory cortex.

Research on music perception has revealed numerous parallels between infants and adults, but these findings have had little influence on adult research. Studies of pitch memory in infants, children, and adults are presented to illustrate potential gains from a developmental approach. Although the prevailing wisdom is that absolute pitch processing dominates in early life until it is supplanted by relative pitch processing, recent research offers no support for that view. After a week of exposure to English folk melodies, infants remember the melodies, but they do not distinguish the original versions from transposed versions. Relative pitch processing dominates later on, but it does not occur at the expense of absolute pitch processing. For example, adults can identify the pitch level of familiar musical recordings in the context of foils that are pitch shifted by one or two semitones. Children 5-9 years of age can identify the pitch level of familiar recordings when the foils are pitch shifted by two semitones but not by one semitone. By contrast, Japanese children are successful in the context of one-semitone shifts. In short, a developmental approach can provide insights of comparable importance on many issues in music cognition.

In this study, event-related brain potentials (ERPs) are used to investigate the processing of musical scale structures from a cross-cultural perspective. ERP reactions reveal that universal listening strategies per se are modified by culture.

We examined 6-month-old infants' long-term memory representations for the pitch of familiar melodies. Infants remembered the relative pitch of the melodies, but the absolute pitch was either not remembered or not a particularly salient attribute.

The etiology and defining characteristics of absolute pitch (AP) have been controversial. To test the importance of musical training in the development of this skill, we developed a new paradigm for identifying AP that is independent of a subject's musical experience. We confirm the efficacy of the paradigm using classically defined AP and non-AP musicians. We then present data from a nonmusician who nevertheless appears to possess AP. We conclude that musical training is not necessary for the development of AP.

Even when simultaneously performing a task unrelated to sounds, the human auditory cortex can precisely model the invariances of the acoustic environment. Data acquired in a mismatch negativity (MMN) paradigm have shown that temporally and spectrally complex sounds as well as their relations are automatically represented in the human auditory cortex. Furthermore, MMN data indicate that these neural sound representations are spatially distinct from phonetic and musical sounds within and between the cerebral hemispheres. Most MMN studies were conducted in pitch dimension, but temporal aspects of sound processing are also under increasing experimentation. To some extent, musical expertise is also reflected in sound representation accuracy as indexed by the MMN paradigm.

Congenital amusia is a lifelong disability, commonly known as tone deafness, that prevents afflicted individuals from developing basic musical skills despite normal audiometry and above-average intellectual, memory, and language skills. Although it is estimated that 4% of the general population would be born with such a musical handicap, the underlying cause is presently unknown. Recently, we proposed that this disorder could be traced to a deficit in pitch perception on the basis of a single case. Here we provide psychophysical evidence for the existence of a generalized defect that is both fine grained and specific to pitch because time is unaffected.

Cortically generated auditory evoked potentials (N1 and P2) were recorded to frequency changes of harmonic and inharmonic complex tones comprising four sinusoidal components. The responses obtained when the frequencies suddenly became stationary after a period of 16/s changes were significantly shorter in latency when the frequencies were harmonically related, possibly implying a process of periodicity detection.

The processing of pitch, a central aspect of music perception, is neurally dissociable from other perceptual functions. Studies using behavioral-lesion techniques as well as brain imaging methods demonstrate that tonal processing recruits mechanisms in areas of the right auditory cortex. Specifically, the right primary auditory area appears to be crucial for fine-grained representation of pitch information. Processing of pitch patterns, such as occurs in melodies, requires higher-order cortical areas, and interactions with the frontal cortex. The latter are likely related to tonal working memory functions that are necessary for the on-line maintenance and encoding of tonal patterns. One hypothesis that may explain why right-hemisphere auditory cortices seem to be so important to tonal processing is that left auditory regions are better suited for rapidly changing broad-band stimuli, such as speech, whereas the right auditory cortex may be specialized for slower narrow-band stimuli, such as tonal patterns. Evidence favoring this hypothesis was obtained in a functional imaging study in which spectral and temporal parameters were varied independently. The hypothesis also receives support from structural studies of the auditory cortex, which indicate that spectral and temporal processing may depend on interhemispheric differences in grey/white matter distribution and other anatomical features.

This paper considers the temporal processing of complex sounds relevant to musical analysis. Functional imaging studies, using positron emission tomography (PET), functional magnetic resonance imaging (fMRI), and magnetoencephalography (MEG), and the psychophysical assessment of patients with lesions allow two different approaches to this. Functional imaging allows the determination of structures normally involved in temporal analysis, while patient studies allow inference about the necessary structures for temporal analysis. Both approaches suggest a hierarchal organization in the brain corresponding to the processing of music. The features of individual notes are analyzed in the pathway up to and including the auditory cortices, while higher-order patterns formed by those features are analyzed by distributed networks in the temporal lobe and frontal lobes distinct from the auditory cortices.

One acoustic feature that plays an important role in pitch perception is frequency. Studies on the processing of frequency in the human and animal brain have shown that the auditory cortex is tonotopically organized: low frequencies are represented laterally whereas high frequencies are represented medially. To date, the study of the functional organization of the human auditory cortex in the processing of frequency has been limited to the use of either scalp-recorded auditory evoked potentials (AEPs), which have relatively poor spatial resolving power, or functional imagery techniques, which have poor temporal resolving power. The present study uses intracerebrally recorded AEPs to explore this topic in the primary and secondary auditory cortices of both hemispheres of the human brain. Recordings were carried out in 45 adult patients with drug-resistant partial seizures. In the right hemisphere, clear spectrally organized tonotopic maps were observed with distinct separations between different frequency-processing regions. AEPs for high frequencies were recorded medially, whereas AEPs for low frequencies were recorded laterally. In the left hemisphere, however, this tonotopic organization was less evident, with different regions involved in the processing of a range of frequencies. The hemisphere-related difference in the processing of tonal frequency is discussed in relation to pitch perception.

The results of the study show that AP possessors performed better in the Hidden Figure Test than did NMs and musicians with RP and that age at which music instruction is initiated affects performance in specific spatial tasks. Individuals who begin extensive musical instruction at a very early age may have an advantage when completing selected spatial tests over those with no formal musical training. However, characteristics other than starting age of musical instruction are associated with AP and seem to affect musicians' performance in the Hidden Figure Test. The differences found between the performance of AP possessors and RP possessors in this nonmusical task suggest further research.

Basic principles of the theory of harmony reflect physiological and anatomical properties of the auditory nervous system and related cognitive systems. This hypothesis is motivated by observations from several different disciplines, including ethnomusicology, developmental psychology, and animal behavior. Over the past several years, we and our colleagues have been investigating the vertical dimension of harmony from the perspective of neurobiology using physiological, psychoacoustic, and neurological methods. Properties of the auditory system that govern harmony perception include (1) the capacity of peripheral auditory neurons to encode temporal regularities in acoustic fine structure and (2) the differential tuning of many neurons throughout the auditory system to a narrow range of frequencies in the audible spectrum. Biologically determined limits on these properties constrain the range of notes used in music throughout the world and the way notes are combined to form intervals and chords in popular Western music. When a harmonic interval is played, neurons throughout the auditory system that are sensitive to one or more frequencies (partials) contained in the interval respond by firing action potentials. For consonant intervals, the fine timing of auditory nerve fiber responses contains strong representations of harmonically related pitches implied by the interval (e.g., Rameau's fundamental bass) in addition to the pitches of notes actually present in the interval. Moreover, all or most of the partials can be resolved by finely tuned neurons throughout the auditory system. By contrast, dissonant intervals evoke auditory nerve fiber activity that does not contain strong representations of constituent notes or related bass notes. Furthermore, many partials are too close together to be resolved. Consequently, they interfere with one another, cause coarse fluctuations in the firing of peripheral and central auditory neurons, and give rise to perception of roughness and dissonance. The effects of auditory cortex lesions on the perception of consonance, pitch, and roughness, combined with a critical reappraisal of published psychoacoustic data on the relationship between consonance and roughness, lead us to conclude that consonance is first and foremost a function of the pitch relationships among notes. Harmony in the vertical dimension is a positive phenomenon, not just a negative phenomenon that depends on the absence of roughness--a view currently held by many psychologists, musicologists, and physiologists.