The complexity-aesthetics relationship for musical rhythm is more fixed than flexible: Evidence from children and expert dancers.

The urge to move to music (groove) depends in part on rhythmic syncopation in the music. For adults, the syncopation-groove relationship has an inverted-U shape: listeners want to move most to rhythms that have some, but not too much, syncopation. However, we do not know whether the syncopation-groove relationship is relatively sensitive to, or resistant to, a listener's experience. In two sets of experiments, we tested whether the syncopation-groove relationship is affected by dance experience or changes through development in childhood. Dancers and nondancers rated groove for 50 rhythmic patterns varying in syncopation. Dancers' and nondancers' ratings did not differ (and Bayesian tests provided substantial evidence that they were equivalent) in terms of mean groove and the optimal level of syncopation. Similarly, ballet and hip-hop dancers' syncopation-groove relationships did not differ. However, dancers had more robust syncopation-groove relationships (higher goodness-of-fit) than nondancers. Children (3-6 years old) completed two tasks to assess their syncopation-groove relationships: In a 2-alternative-forced choice task, children compared rhythms from 2 of 3 possible levels of syncopation (low, medium, and high) and chose which rhythm in a pair was better for dancing. In a dance task, children danced to the same rhythms. Results from both tasks indicated that for children, as for adults, medium syncopation rhythms elicit more groove than low syncopation rhythms. A follow-up experiment replicated the 2-alternative-forced choice task results. Taken together, the results suggest the optimal level of syncopation for groove is resistant to experience, although experience may affect the robustness of the inverted-U relationship. RESEARCH HIGHLIGHTS: In Experiment 1, dancers and nondancers rated groove (the urge to move) for musical rhythms, demonstrating the same inverted-U relationships between syncopation and groove. In Experiment 2, children and adults both chose rhythms with moderate syncopation more than low syncopation as more groove-inducing or better for dancing. Children also danced more for moderate than low syncopation, showing a close perception-behavior relationship across tasks. Similarities in the syncopation-groove relationship regardless of dance training and age suggest that this perceptual and behavioral groove response to rhythmic complexity may be quite resistant to experience.

Neural entrainment is associated with subjective groove and complexity for performed but not mechanical musical rhythms.

Both movement and neural activity in humans can be entrained by the regularities of an external stimulus, such as the beat of musical rhythms. Neural entrainment to auditory rhythms supports temporal perception, and is enhanced by selective attention and by hierarchical temporal structure imposed on rhythms. However, it is not known how neural entrainment to rhythms is related to the subjective experience of groove (the desire to move along with music or rhythm), the perception of a regular beat, the perception of complexity, and the experience of pleasure. In two experiments, we used musical rhythms (from Steve Reich's Clapping Music) to investigate whether rhythms that are performed by humans (with naturally variable timing) and rhythms that are mechanical (with precise timing), elicit differences in (1) neural entrainment, as measured by inter-trial phase coherence, and (2) subjective ratings of the complexity, preference, groove, and beat strength of rhythms. We also combined results from the two experiments to investigate relationships between neural entrainment and subjective perception of musical rhythms. We found that mechanical rhythms elicited a greater degree of neural entrainment than performed rhythms, likely due to the greater temporal precision in the stimulus, and the two types only elicited different ratings for some individual rhythms. Neural entrainment to performed rhythms, but not to mechanical ones, correlated with subjective desire to move and subjective complexity. These data, therefore, suggest multiple interacting influences on neural entrainment to rhythms, from low-level stimulus properties to high-level cognition and perception.

Commonality and variation in mental representations of music revealed by a cross-cultural comparison of rhythm priors in 15 countries.

Music is present in every known society but varies from place to place. What, if anything, is universal to music cognition? We measured a signature of mental representations of rhythm in 39 participant groups in 15 countries, spanning urban societies and Indigenous populations. Listeners reproduced random 'seed' rhythms; their reproductions were fed back as the stimulus (as in the game of 'telephone'), such that their biases (the prior) could be estimated from the distribution of reproductions. Every tested group showed a sparse prior with peaks at integer-ratio rhythms. However, the importance of different integer ratios varied across groups, often reflecting local musical practices. Our results suggest a common feature of music cognition: discrete rhythm 'categories' at small-integer ratios. These discrete representations plausibly stabilize musical systems in the face of cultural transmission but interact with culture-specific traditions to yield the diversity that is evident when mental representations are probed across many cultures.

Consequences of Contracting COVID-19 or Taking the COVID-19 Vaccine for Individuals with a History of Lyme Disease.

Individuals with Lyme disease can be very symptomatic. This survey compares the burden of illness for individuals with a history of Lyme disease (HLD) with individuals with a HLD who have either contracted COVID-19 or who have taken the COVID-19 vaccine. The findings describe the relative symptom burden among these three groups using a cross-sectional descriptive survey investigating the burden of Lyme disease in a pandemic. The survey includes the General Symptom Questionnaire-30 (GSQ-30), a brief self-report scale designed to assess the symptom burden in Lyme disease (LD). The results of this survey show that the overall burden of illness among individuals with HLD is not significantly different after contracting COVID-19 or after COVID-19 vaccination. A new survey will be needed to better understand why one in five individuals with a HLD reported long COVID after contracting COVID-19. These results should help clinicians and their patients to discuss the consequences of contracting a COVID-19 infection or being vaccinated against COVID-19.

Undetectable very-low frequency sound increases dancing at a live concert.

Does low frequency sound (bass) make people dance more? Music that makes people want to move tends to have more low frequency sound, and bass instruments typically provide the musical pulse that people dance to1. Low pitches confer advantages in perception and movement timing, and elicit stronger neural responses for timing compared to high pitches2, suggesting superior sensorimotor communication. Low frequency sound is processed via vibrotactile3 and vestibular4 (in addition to auditory) pathways, and stimulation of these non-auditory modalities in the context of music can increase ratings of groove (the pleasurable urge to move to music)3, and modulate musical rhythm perception4. Anecdotal accounts describe intense physical and psychological effects of low frequencies, especially in electronic dance music5, possibly reflecting effects on physiological arousal. We do not, however, know if these associations extend to direct causal effects of low frequencies in complex, real-world, social contexts like dancing at concerts, or if low frequencies that are not consciously detectable can affect behaviour. We tested whether non-auditory low-frequency stimulation would increase audience dancing by turning very-low frequency (VLF) speakers on and off during a live electronic music concert and measuring audience members' movements using motion-capture. Movement increased when VLFs were present, and because the VLFs were below or near auditory thresholds (and a subsequent experiment suggested they were undetectable), we believe this represents an unconscious effect on behaviour, possibly via vestibular and/or tactile processing.

Collective dynamics support group drumming, reduce variability, and stabilize tempo drift.

Humans are social animals who engage in a variety of collective activities requiring coordinated action. Among these, music is a defining and ancient aspect of human sociality. Human social interaction has largely been addressed in dyadic paradigms, and it is yet to be determined whether the ensuing conclusions generalize to larger groups. Studied more extensively in non-human animal behavior, the presence of multiple agents engaged in the same task space creates different constraints and possibilities than in simpler dyadic interactions. We addressed whether collective dynamics play a role in human circle drumming. The task was to synchronize in a group with an initial reference pattern and then maintain synchronization after it was muted. We varied the number of drummers from solo to dyad, quartet, and octet. The observed lower variability, lack of speeding up, smoother individual dynamics, and leader-less inter-personal coordination indicated that stability increased as group size increased, a sort of temporal wisdom of crowds. We propose a hybrid continuous-discrete Kuramoto model for emergent group synchronization with a pulse-based coupling that exhibits a mean field positive feedback loop. This research suggests that collective phenomena are among the factors that play a role in social cognition.

Comparison of Spontaneous Motor Tempo during Finger Tapping, Toe Tapping and Stepping on the Spot in People with and without Parkinson's Disease.

OBJECTIVE: Spontaneous motor tempo (SMT), observed in walking, tapping and clapping, tends to occur around 2 Hz. Initiating and controlling movement can be difficult for people with Parkinson's (PWP), but studies have not identified whether PWP differ from controls in SMT. For community-based interventions, e.g. dancing, it would be helpful to know a baseline SMT to optimize the tempi of cued activities. Therefore, this study compared finger tapping (FT), toe tapping (TT) and stepping 'on the spot' (SS) in PWP and two groups of healthy controls [age-matched controls (AMC) and young healthy controls (YHC)], as SMT is known to change with age. METHODS: Participants (PWP; n = 30, AMC; n = 23, YHC; n = 35) were asked to tap or step on the spot at a natural pace for two trials lasting 40 seconds. The central 30 seconds were averaged for analyses using mean inter-onset intervals (IOI) and coefficient of variation (CoV) to measure rate and variability respectively. RESULTS: PWP had faster SMT than both control groups, depending on the movement modality: FT, F(2, 87) = 7.92, p < 0.01 (PWP faster than YHC); TT, F(2, 87) = 4.89, p = 0.01 (PWP faster than AMC); and SS, F(2, 77) = 3.26, p = 0.04 (PWP faster than AMC). PWP had higher CoV (more variable tapping) than AMC in FT only, F(2, 87) = 4.10, p = 0.02. CONCLUSION: This study provides the first direct comparison of SMT between PWP and two control groups for different types of movements. RESULTS: suggest SMT is generally faster in PWP than control groups, and more variable when measured with finger tapping compared to stepping on the spot.

Clinical trials validate the severity of persistent Lyme disease symptoms.

BACKGROUND: Persistent Lyme Disease Symptoms (PLDS) have included fatigue, headaches, poor concentration and memory, lightheadedness, joint pain, and mood disturbances. Evidence-based guidelines committees disagree over the severity of PLDS. The 2004 International Lyme and Associated Diseases Society (ILADS) concluded that PLDS are severe. The 2006 Infectious Disease Society of America (IDSA) guidelines committee concluded that PLDS are nothing more than the "aches and pains of daily living" and an ad hoc International Lyme group concluded that PLDS are "symptoms common in persons who have never had Lyme disease." HYPOTHESIS: Clinical trials validate the severity of persistent Lyme disease symptoms. EVALUATION OF THE HYPOTHESIS: There are 22 standardized instruments used to measure the severity of PLDS among the four published National Institutes of Health (NIH) sponsored double-blind randomized placebo-controlled trials (RCTs). VALIDATING THE HYPOTHESIS: All four NIH sponsored RCTs validate the severity of PLDS. PLDS are as severe as symptoms seen in other serious chronic illnesses, and result in a quality of life lower than for the general population as determined by 22 standardized measures of QOL, including fatigue, pain, role function, psychopathology, and cognition. None of the four RCTs support the IDSA hypothesis that PLDS are nothing more than "the aches and pains of daily living" nor the ad hoc International Lyme group conclusion that PLDS are "symptoms common in persons who have never had Lyme disease." IMPLICATIONS OF THE HYPOTHESIS: If the QOL of life for these patients is as poor as for patients with other serious chronic diseases, their symptoms need to be addressed by their doctors. Studies differ as to the precise cause of PLDS, the most effective treatments, and whether a cure is possible. But the fact that there is disagreement is not a license for physicians to ignore or turn away patients complaining of PLDS, or to dismiss their symptoms as purely psychosomatic. For physicians, the goal or purpose of treating PLDS should be the same as their purpose in treating other chronic illnesses that result in a poor QOL: vigorous pursuit of a cure, and where a cure proves impossible, amelioration of patients' symptoms and suffering. Even if this hypothesis fails to be apply to more than a fraction of the total Lyme disease population, this still represents a significant number of patients, and these findings could address a neglected aspect of caring for patients with Lyme disease.

Evaluating Affordable Cranial Ultrasonography in East African Neonatal Intensive Care Units.

Neuroimaging is a valuable diagnostic tool for the early detection of neonatal brain injury, but equipment and radiologic staff are expensive and unavailable to most hospitals in developing countries. We evaluated an affordable, portable ultrasound machine as a quantitative and qualitative diagnostic tool and to establish whether a novice sonographer could effectively operate the equipment and obtain clinically important information. Cranial ultrasonography was performed on term healthy, pre-term and term asphyxiated neonates in Rwandan and Kenyan hospitals. To evaluate the detection of ventriculomegaly and compression injuries, we measured the size of the lateral ventricles and corpus callosum. The images were also assessed for the presence of other cerebral abnormalities. Measurements were reliable across images, and cases of clinically relevant ventriculomegaly were detected. A novice sonographer had good-to-excellent agreement with an expert. This study demonstrates that affordable equipment and cranial ultrasound protocols can be used in low-resource settings to assess the newborn brain.