A Mechanism for Sensorimotor Translation in Singing: the Multi-Modal Imagery Association (MMIA) Model

WE PROPOSE A NEW FRAMEWORK TO UNDERSTAND singing accuracy, based on multi-modal imagery associations: the MMIA model. This model is based on recent data suggesting a link between auditory imagery and singing accuracy, evidence for a link between imagery and the functioning of internal models for sensorimotor associations, and the use of imagery in singing pedagogy. By this account, imagery involves automatic associations between different modalities, which in the present context comprise associations between pitch height and the regulation of vocal fold tension. Importantly, these associations are based on probabilistic relationships that may vary with respect to their precision and accuracy. We further describe how this framework may be extended to multi-modal associations at the sequential level, and how these associations develop. The model we propose here constitutes one part of a larger architecture responsible for singing, but at the same time is cast at a general level that can extend to multi-modal associations outside the domain of singing

Pitch Imitation Ability in Mental Transformations of Melodies

Previous research suggests that individuals with a vocal pitch imitation deficit (VPID, a.k.a. poor-pitch singers ) experience less vivid auditory images than accurate imitators (pfordresher & halpern, 2013), based on self-report. in the present research we sought to test this proposal directly by having accurate and VPID imitators produce or recognize short melodies based on their original form (untransformed), or after mentally transforming the auditory image of the melody. For the production task, group differences were largest during the untransformed imitation task. importantly, producing mental transformations of the auditory image degraded performance for all participants, but were relatively more disruptive to accurate than to VPID imitators. These findings suggest that VPID is due partly to poor initial imagery formation, as manifested by production of untransformed melodies. By contrast, producing a transformed mental image may rely on working memory ability, which is more equally matched across participants. This interpretation was further supported by correlations with self-reports of auditory imagery and measures of working memory

Lamina-specific population encoding of cutaneous signals in the spinal dorsal horn using multi-electrode arrays

The dorsal spinal cord (DH) is a complex laminar structure integrating peripheral signals into the central nervous system. Spinal somatosensory processing is commonly measured electrophysiologically in vivo by recording the activity of individual Wide Dynamic Range neurons in the deep DH and extrapolating their behaviour to all cells in every lamina. This fails to account for the specialised processes that occur in each lamina and the considerable heterogeneity in cellular phenotype within and between laminae. Here we overcome this oversimplification by employing linear multi‐electrode arrays (MEAs) in the DH of anaesthetized rats to simultaneously measure activity across all laminae. The MEAs, comprised of 16‐channels, were inserted into the lumbar dorsal horn and peripheral neurones activated electrically via transcutaneous electrodes and ethologically with von Frey hairs (vFh) or an aluminium heating block. Ascending electrical stimuli showed fibre thresholds with distinct dorso‐ventral innervation profiles. Wind up was observed across the DH during the C‐fibre and post‐discharge latencies following 0.5Hz stimulation. Intrathecal application of morphine (5ng/50ul) significantly reduced Aδ and C‐fibre evoked activity in deep and superficial DH. Light vFhs (≤10g) predominantly activated intermediate and deep laminae whereas noxious vFh (26g) also activated the superficial laminae. Noxious heat (55°C) induced significantly greater activity in the superficial and deep laminae than the innocuous control (30°C). The application of these arrays produced the first description of the processing of innocuous and noxious stimuli throughout the intact DH

Holistic Processing of Words Modulated by Reading Experience

Perceptual expertise has been studied intensively with faces and object categories involving detailed individuation. A common finding is that experience in fulfilling the task demand of fine, subordinate-level discrimination between highly similar instances is associated with the development of holistic processing. This study examines whether holistic processing is also engaged by expert word recognition, which is thought to involve coarser, basic-level processing that is more part-based. We adopted a paradigm widely used for faces – the composite task, and found clear evidence of holistic processing for English words. A second experiment further showed that holistic processing for words was sensitive to the amount of experience with the language concerned (native vs. second-language readers) and with the specific stimuli (words vs. pseudowords). The adoption of a paradigm from the face perception literature to the study of expert word perception is important for further comparison between perceptual expertise with words and face-like expertise

The Role of Long-Term Memory in Mental Transformations of Pitch

Most people can recognize and perform a musical piece under a variety of transformations such as altering the key or varying the tempo. However, we also know that other mental transformations of music can be difficult to generate and to recognize. Two factors that might affect this mental flexibility are the familiarity of the piece and musical ability of the listener, in this case singing accuracy. The current experiment addressed the accuracy and flexibility of representations of novel and traditional melodies among accurate, moderate, and inaccurate singers. Participants sang or recognized melodies in either their original form or as a transformation: a transposition, a shift of serial position, and a reversal of the melody. Participants showed an advantage for traditional melodies, but only when singing or recognizing tunes in their original form. Participants were similarly disrupted by mental transformations of traditional and novel tunes in both production and recognition tasks. Interestingly, we found that the only advantage for traditional melodies when singing repetitions of the melody occurred among the moderate singers, but all three groups showed an advantage for traditional melodies when recognizing exact repetitions

The effect of musical training and language background on vocal imitation of pitch in speech and song

Vocal imitation plays a critical function in the development and use of both language and music. Previous studies have reported more accurate imitation for sung pitch than spoken pitch, which might be attributed to the structural differences in acoustic signals and/or the distinct mental representations of pitch patterns across speech and music. The current study investigates the interaction between bottom-up (i.e., acoustic structure) and top-down (i.e., participants’ language and musical background) factors on pitch imitation by comparing speech and song imitation accuracy across four groups: English and Mandarin speakers with or without musical training. Participants imitated pitch sequences that were characteristic of either song or speech, derived from pitch patterns in English and Mandarin spoken sentences. Overall, song imitation was more accurate than speech imitation, and this advantage was larger for English than Mandarin pitch sequences, regardless of participants’ musical and language experiences. This effect likely reflects the perceptual salience of linguistic tones in Mandarin relative to English speech. Music and language knowledge were associated with optimal imitation of different acoustic features. Musicians were more accurate in matching absolute pitch across syllables and musical notes compared to non-musicians. By contrast, Mandarin speakers were more accurate at imitating fine-grained changes within and across pitch events compared to English speakers. These results suggest that different top-down factors (i.e., language and musical background) influence pitch imitation ability for different dimensions of bottom-up features (i.e., absolute pitch and relative pitch patterns)

Subvocalization During Preparatory and Non-preparatory Auditory Imagery

Given previous results showing that auditory imagery is associated with subvocal muscle movements related to pitch control, the present study addressed whether subvocalization of pitch is differentially involved during imagery that precedes the execution of an imagined action as compared to non-preparatory imagery. We examined subvocal activity using surface electromyography (sEMG) during auditory imagery that preceded sung reproduction of a pitch sequence (preparatory) or recognition of a pitch sequence (non-preparatory). On different trials, participants either imagined the sequence as presented, or imagined a mental transformation of that sequence. Behavioral results replicated previous findings of poorer reproduction and recognition of transformed sequences compared to sequences in their original form. Physiological results indicated that subvocal activity was significantly above baseline for all conditions, greater than activity observed for the bicep control site, and greater for longer sequences, but did not reliably scale with transformation type. Furthermore, greater subvocal activity during preparatory imagery was associated with greater subvocal activity during non-preparatory imagery for muscles involved in pitch control and articulation. Muscle activity involved in pitch control was similarly recruited for both preparatory and non-preparatory auditory imagery. In contrast, muscle activity involved in vocal articulation was most strongly recruited during motor preparation. Our findings suggest that pitch imagery recruits subvocal muscle activity regardless of whether the imagined action is intended to be effecte

Holistic Processing of Chinese Characters

Enhanced holistic processing (obligatory attention to all parts of an object) has been associated with different types of perceptual expertise involving faces, cars, fingerprints, musical notes, English words, etc. Curiously Chinese characters are regarded as an exception, as indicated by the lack of holistic processing found for experts (Hsiao and Cottrell, 2009). The ceiling performance of experts, however, may have caused this null effect. We revisit this issue by adopting the often-used face-composite sequential-matching task to two-part Chinese characters. Participants matched the target halves (left or right) of two characters while ignoring the irrelevant halves. Both Chinese readers (experts) and non-Chinese readers (novices) showed holistic processing. Follow-up experiments suggested different origins of the effects for the two groups. For experts, holistic processing was sensitive to the amount of experience with the characters, as it was larger for words than non-words (formed by swapping the two parts of a valid character). Novices, however, showed similar degree of holistic processing to words and non-words, suggesting that their effects were more related to their inefficient decomposition of a complex, character-like pattern into parts. Overall these findings suggest that holistic processing may be a marker of expertise with Chinese characters, contrary to previous claims