Roni Y. Granot

Molecular genetic studies of the arginine vasopressin 1a receptor (AVPR1a) and the oxytocin receptor (OXTR) in human behaviour: from autism to altruism with some notes in between

Converging evidence from both human and animal studies has highlighted the pervasive role of two neuropeptides, oxytocin (OXT) and arginine vasopressin (AVP), in mammalian social behaviours. Recent molecular genetic studies of the human arginine vasopressin 1a (AVPR1a) and oxytocin (OXTR) receptors have strengthened the evidence regarding the role of these two neuropeptides in a range of normal and pathological behaviours. Significant association between both AVPR1a repeat regions and OXTR single nucleotide polymorphisms (SNPs) with risk for autism has been provisionally shown which was mediated by socialization skills in our study. AVPR1a has also been linked to eating behaviour in both clinical and non-clinical groups, perhaps reflecting the social and ritualistic side of eating behaviour. Evidence also suggests that repeat variations in AVPR1a are associated with two other social domains in Homo sapiens: music and altruism. AVPR1a was associated with dance and musical cognition which we theorize as reflecting the ancient role of this hormone in social interactions executed by vocalization, ritual movement and dyadic (mother-offspring) and group communication. Finally, we have shown that individual differences in allocation of funds in the dictator game, a laboratory game of pure altruism, is predicted by length of the AVPR1a RS3 promoter-region repeat echoing the mechanism of this hormones action in the vole model of affiliative behaviours and facilitation of positive group interactions. While still in its infancy, the current outlook for molecular genetic investigations of AVP-OXT continues to be fascinating. Future studies should profitably focus on pharmacogenomic and genomic imaging strategies facilitated by the ease and efficacy of manipulating AVP-OXT neurotransmission by intranasal administration. Importantly, physiological measures, behavioural paradigms and brain activation can be informed by considering between-group and also within-group individual differences defined by common polymorphisms. Ultimately, investigators should strive to develop a cohesive model explaining how genomic variations are translated into individual and group differences in higher-order social behaviours.

Processing specificity for human voice stimuli: electrophysiological evidence.

Recent neuroimaging studies have provided evidence for localized perceptual specificity in the processing of human voice stimuli, paralleling the specificity for human faces. This study attempted to delineate the perceptual features of human voices yielding selective processing, and to characterize its time-course. Electrophysiological recordings revealed a positive potential peaking at 320 ms post-stimulus onset, in response to sung tones compared with fundamental-frequency-matched instrumental tones, when both categories were distracters in an oddball task. This voice-specific response (VSR) evoked under conditions different from those yielding positivity at that latency in other contexts, indicates the overriding salience of voice stimuli, possibly reflecting the operation of a gating system directing voice stimuli to be processed differently from other acoustic stimuli.

Neural sensitivity to human voices: ERP evidence of task and attentional influences

In an earlier study, we found that human voices evoked a positive event-related potential (ERP) peaking at approximately 320 ms after stimulus onset, distinctive from those elicited by instrumental tones. Here we show that though similar in latency to the Novelty P3, this Voice-Sensitive Response (VSR) differs in antecedent conditions and scalp distribution. Furthermore, when participants were not attending to stimuli, the response to voices was undistinguished from other harmonic stimuli (strings, winds, and brass). During a task requiring attending to a feature other than timbre, voices were not distinguished from voicelike stimuli (strings), but were distinguished from other harmonic stimuli. We suggest that the component elicited by voices and similar sounds reflects the allocation of attention on the basis of stimulus significance (as opposed to novelty), and propose an explanation of the task and attentional factors that contribute to the effect.

Absolute pitch-electrophysiological evidence

People who have the ability to label or to produce notes without any reference are considered to possess Absolute Pitch (AP). Others, who need a reference in order to identify the notes, possess Relative Pitch (RP). The AP ability is assumed to reflect a unique, language-like representation of non-lexical musical notes in memory. The purpose of this study was to examine this assumption by comparing Event Related Potentials (ERP) of musicians with and without AP, to lexical and non-lexical representation of musical material. Subjects were eighteen young adult musicians. Seven were AP and eleven RP. Auditory stimuli, presented through earphones, were piano notes (non-lexical) or a voice saying the notes name (lexical). Visual stimuli, presented on a computer display were note symbols (non-lexical) or letters (lexical). Subjects performed a number of tasks, combining the two modalities (visual and auditory) and stimulus types (lexical and non-lexical), and reaction times (RT), performance accuracy and evoked potentials were recorded. The tasks forced the subjects to transfer mental representations of musical material from one mode to another. Our most important findings were the differences, between groups, in the scalp distribution of P300 amplitudes. We conclude that absolute pitch possessors use the same internal language as relative pitch possessors, when possible, but the distribution of the underlying brain activity is different between AP and RP subjects.

The enigma of dyslexic musicians

Musicians are known to have exceptional sensitivity to sounds, whereas poor phonological representations (or access to these representations) are considered a main characteristic of dyslexic individuals. Though these two characteristics refer to different abilities that are related to non-verbal and verbal skills respectively, the recent literature suggests that they are tightly related. However, there are informal reports of dyslexic musicians. To better understand this enigma, two groups of musicians were recruited, with and without a history of reading difficulties. The pattern of reading difficulties found among musicians was similar to that reported for non-musician dyslexics, though its magnitude was less severe. In contrast to non-musician dyslexics, their performance in pitch and interval discrimination, synchronous tapping and speech perception tasks, did not differ from the performance of their musician peers, and was superior to that of the general population. However, the auditory working memory scores of dyslexic musicians were consistently poor, including memory for rhythm, melody and speech sounds. Moreover, these abilities were inter-correlated, and highly correlated with their reading accuracy. These results point to a discrepancy between their perceptual and working memory skills rather than between sensitivity to speech and non-speech sounds. The results further suggest that in spite of intensive musical training, auditory working memory remains a bottleneck to the reading accuracy of dyslexic musicians.

Memory for Tonal Pitches: A Music-Length Effect Hypothesis

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.

Musically puzzling I: Sensitivity to overall structure in the sonata form?

Previous studies have suggested that listeners are not sensitive to the overall tonal structure of musical pieces. This assumption is reexamined in the current study in an active musical puzzle task, with no time constraints, focusing on the presumably most directional musical form – the sonata form. In our first study (reported here, and referred to as “the Mozart study”), participants with varying levels of musical training were presented with disordered sections of Mozart’s piano sonata K. 570/I in B flat major and asked to rearrange the ten sections into a musically logical coherent whole. A second study (to be reported in Musicae Scientiae issue 16[1]) replicated the task in a different group of participants who listened to Haydn’s piano sonata, Hob: XVI-34/I in E minor. In contrast with previous studies, we do not focus on listeners’ ability to recover the original sonatas. Rather, we explore emergent patterns in their responses using new types of analysis. Our results indicate that listeners show: (1) Some sensitivity to the overall structure of A-B-A’ around the non-stable B section; (2) Non- trivial sensitivity to overall “directionality” through a new type of analysis (“distance score”); (3) Correct grouping and placement of developmental sections possibly related to listener’s sensitivity to musical tension; (4) Sensitivity to opening and closing gestures, thematic similarity and surface cues and; (5) No sensitivity to global harmonic structure.

Intensity changes and perceived similarity: Inter-parametric analogies

Music theorists and psychologists have described diverse musical processes in terms of changes (increase or decrease) in “intensity”. This paper examines the hypothesis that analogous intensity changes in different musical parameters can be perceived as similar, and discusses implications of such perception for music analysis. In the experiment reported, participants rated the degree to which members of pairs of musical stimuli were similar in character to a “standard” — a crescendo on a repeated tone. One member of each pair presented an “increase” in a specific musical parameter, while the other presented a “decrease” (e.g., pitch ascent vs. descent). Parameters investigated included melodic direction and attack rate and their combinations, pitch interval size, motivic pace, and harmonic tension. For most parameters, the intensifying figure was rated as closer to the standard (itself intensifying) than its abating counterpart. Perceived similarity was strongest between figures presenting intensification in dynamics (crescendo) and pitch direction (ascent), while similarity between intensification in dynamics and tempo (accelerando) was weaker, and perceived mainly by musically-trained subjects. Similarity between dynamic change and harmonic progression was perceived only when the latter involved manipulation of dissonance, and dynamic intensification and increase in pitch interval size were perceived as similar only for ascending intervals. Importantly, the combined effect of melodic direction and attack rate on similarity perception was additive, rather than interactive, though the effect of melodic direction was significantly stronger. This result supports models of “integrated intensity contours” (Berry, 1976; Todd, 1994), but suggests different weighting for different musical parameters. In sum, results indicate that listeners can perceive intensity contours in different parameters as analogous, and thus suggest that intensity contours may serve as musical “gestures”, regardless of the specific parameters depicting them. The implications of these results to music analysis are discussed with regard to motivic structure, thematic prototypicality, and structural functions of intensity contours.

Primary versus secondary musical parameters and the classification of melodic motives

Music theorists often maintain that motivic categorization in music is determined by “primary” musical parameters — music-specific aspects of pitch and temporal structure, like pitch intervals or metric hierarchies, serving as bases for musical syntax. In contrast, “secondary” parameters, including important aspects of extra-musical auditory perception like loudness, pitch register and timbre, do not establish motivic categories. We examined systematically the effects of contrasts in primary vis-à-vis secondary musical parameters on listeners’ melodic classification. Matrices of melodic patterns, each presenting 8 motives, were created by all interactions of two contrasting conditions in three musical features. In Experiment 1, four matrices manipulated pitch contour, pitch-interval class, and a compound feature involving the secondary parameters of dynamics, pitch register and articulation. In Experiment 2, four different matrices manipulated rhythmic structure (metrical and durational accent), pitch intervals, and the compound feature used in Exp1. Participants (95 participants, 27 musically trained, in Exp. 1; 88 participants, 23 musically trained, in Exp. 2) classified stimuli in each matrix into two equal-numbered (4–4) groups of motives “belonging together.” In both experiments, most participants used contrast in secondary parameters as a basis for classification, while few classifications relied on differences in pitch interval (Exp. 2) or interval class (Exp. 1). Classifications by musically trained participants also applied melodic contour and rhythm. Results suggest a hierarchy of musical parameters that challenges those suggested by most music theorists. We discuss the ramifications of the results for notions of perceived thematic-motivic structure in music, and consequentially for cognitively-informed music analysis.

Effects of arginine vasopressin on musical working memory

Previous genetic studies showed an association between variations in the gene coding for the 1a receptor of the neuro-hormone arginine vasopressin (AVP) and musical working memory (WM). The current study set out to test the influence of intranasal administration (INA) of AVP on musical as compared to verbal WM using a double blind crossover (AVP—placebo) design. Two groups of 25 males were exposed to 20 IU of AVP in one session, and 20 IU of saline water (placebo) in a second session, 1 week apart. In each session subjects completed the tonal subtest from Gordons “Musical Aptitude Profile,” the interval subtest from the “Montreal Battery for Evaluation of Amusias (MBEA),” and the forward and backward digit span tests. Scores in the digit span tests were not influenced by AVP. In contrast, in the music tests there was an AVP effect. In the MBEA test, scores for the group receiving placebo in the first session (PV) were higher than for the group receiving vasopressin in the first session (VP) (p < 0.05) with no main Session effect nor Group × Session interaction. In the Gordon test there was a main Session effect (p < 0.05) with scores higher in the second as compared to the first session, a marginal main Group effect (p = 0.093) and a marginal Group × Session interaction (p = 0.88). In addition we found that the group that received AVP in the first session scored higher on scales indicative of happiness, and alertness on the positive and negative affect scale, (PANAS). Only in this group and only in the music test these scores were significantly correlated with memory scores. Together the results reflect a complex interaction between AVP, musical memory, arousal, and contextual effects such as session, and base levels of memory. The results are interpreted in light of musics universal use as a means to modulate arousal on the one hand, and AVPs influence on mood, arousal, and social interactions on the other.