RESUMO
We addressed how rhythm complexity influences auditory-motor synchronization in musically trained individuals who perceived and produced complex rhythms while EEG was recorded. Participants first listened to two-part auditory sequences (Listen condition). Each part featured a single pitch presented at a fixed rate; the integer ratio formed between the two rates varied in rhythmic complexity from low (1:1) to moderate (1:2) to high (3:2). One of the two parts occurred at a constant rate across conditions. Then, participants heard the same rhythms as they synchronized their tapping at a fixed rate (Synchronize condition). Finally, they tapped at the same fixed rate (Motor condition). Auditory feedback from their taps was present in all conditions. Behavioral effects of rhythmic complexity were evidenced in all tasks; detection of missing beats (Listen) worsened in the most complex (3:2) rhythm condition, and tap durations (Synchronize) were most variable and least synchronous with stimulus onsets in the 3:2 condition. EEG power spectral density was lowest at the fixed rate during the 3:2 rhythm and greatest during the 1:1 rhythm (Listen and Synchronize). ERP amplitudes corresponding to an N1 time window were smallest for the 3:2 rhythm and greatest for the 1:1 rhythm (Listen). Finally, synchronization accuracy (Synchronize) decreased as amplitudes in the N1 time window became more positive during the high rhythmic complexity condition (3:2). Thus, measures of neural entrainment corresponded to synchronization accuracy, and rhythmic complexity modulated the behavioral and neural measures similarly.
Assuntos
Percepção Auditiva , Percepção do Tempo , Estimulação Acústica , Retroalimentação Sensorial , HumanosRESUMO
To coordinate their actions successfully with auditory events, individuals must be able to adapt their behaviour flexibly to environmental changes. Previous work has shown that musical training enhances the flexibility to synchronize behaviour with a wide range of stimulus periods. The current experiment investigated whether musical training enhances temporal adaptation to period perturbations as listeners tapped with a metronome, and whether this enhancement is specific to individuals' Spontaneous Production Rates (SPRs; individuals' natural uncued rates). Both musicians and nonmusicians adapted more quickly to period perturbations that slowed down than to those that sped up. Importantly, musicians adapted more quickly to all period perturbations than nonmusicians. Fits of a damped harmonic oscillator model to the tapping measures confirmed musicians' faster adaptation and greater responsiveness to period perturbations. These results suggest that, even when the task is tailored to individual SPRs, musical training increases the flexibility with which individuals can adapt to changes in their environment during auditory-motor tasks.
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Adaptação Psicológica/fisiologia , Percepção Auditiva/fisiologia , Atividade Motora/fisiologia , Música , Desempenho Psicomotor/fisiologia , Percepção do Tempo/fisiologia , Adulto , Feminino , Humanos , Masculino , Adulto JovemRESUMO
OBJECTIVE: To assess the association of very preterm infants' brain size at term-equivalent age with physical growth from birth to term and body composition at term. STUDY DESIGN: We studied 62 infants born at <33 weeks of gestation. At birth and term, we measured weight and length and calculated body mass index. At term, infants underwent air displacement plethysmography to determine body composition (fat and fat-free mass) and magnetic resonance imaging to quantify brain size (bifrontal diameter, biparietal diameter, transverse cerebellar distance). We estimated associations of physical growth (Z-score change from birth to term) and body composition with brain size, adjusting for potential confounders using generalized estimating equations. RESULTS: The median gestational age was 29 weeks (range, 24.0-32.9 weeks). Positive gains in weight and body mass index Z-score were associated with increased brain size. Each additional 100 g of fat-free mass at term was associated with larger bifrontal diameter (0.6 mm; 95% CI, 0.2-1.0 mm), biparietal diameter (0.7 mm; 95% CI, 0.3-1.1 mm), and transverse cerebellar distance (0.3 mm; 95% CI, 0.003-0.5 mm). Associations between fat mass and brain metrics were not statistically significant. CONCLUSIONS: Weight and body mass index gain from birth to term, and lean mass-but not fat-at term, were associated with larger brain size. Factors that promote lean mass accrual among preterm infants may also promote brain growth.
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Composição Corporal , Encéfalo/crescimento & desenvolvimento , Desenvolvimento Infantil , Recém-Nascido Prematuro/crescimento & desenvolvimento , Feminino , Humanos , Recém-Nascido , Estudos Longitudinais , Imageamento por Ressonância Magnética , Masculino , Pletismografia , Estudos ProspectivosRESUMO
Objectives. To determine what role the 88 000 Housing and Urban Development-Veterans Affairs Supportive Housing (HUD-VASH) vouchers for permanent supportive housing among US veterans distributed between 2008 and 2017 played in the significant fall in veterans' homelessness over the same time period.Methods. Using a panel data set at the Continuum of Care level over the 2007 to 2017 period, we correlated changes in vouchers with permanent supportive housing units and measures of homelessness. To reduce concerns about omitted variables bias, we used a 2-stage least-squares procedure. The instrument is a Bartik-type shift-share variable. Specifically, for the cumulative vouchers received at the local level, we used the share of the nation's homeless veterans from the local level in the year before the HUD-VASH program multiplied by the cumulative number of vouchers distributed at the national level up to that point.Results. For each additional voucher, permanent supportive housing units increased by 0.9 and the number of homeless veterans decreased by 1.Conclusions. Our results indicate the HUD-VASH program worked as intended and veterans' homelessness would have risen substantially over the past decade without the program.
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Pessoas Mal Alojadas/estatística & dados numéricos , Assistência Pública/estatística & dados numéricos , Veteranos/estatística & dados numéricos , Humanos , Estados Unidos , United States Department of Veterans AffairsRESUMO
Auditory feedback of actions provides additional information about the timing of one's own actions and those of others. However, little is known about how musicians and nonmusicians integrate auditory feedback from multiple sources to regulate their own timing or to (intentionally or unintentionally) coordinate with a partner. We examined how musical expertise modulates the role of auditory feedback in a two-person synchronization-continuation tapping task. Pairs of individuals were instructed to tap at a rate indicated by an initial metronome cue in all four auditory feedback conditions: no feedback, self-feedback (cannot hear their partner), other feedback (cannot hear themselves), or full feedback (both self and other). Participants within a pair were either both musically trained (musicians), both untrained (nonmusicians), or one musically trained and one untrained (mixed). Results demonstrated that all three pair types spontaneously synchronized with their partner when receiving other or full feedback. Moreover, all pair types were better at maintaining the metronome rate with self-feedback than with no feedback. Musician pairs better maintained the metronome rate when receiving other feedback than when receiving no feedback; in contrast, nonmusician pairs were worse when receiving other or full feedback compared to no feedback. Both members of mixed pairs maintained the metronome rate better in the other and full feedback conditions than in the no feedback condition, similar to musician pairs. Overall, nonmusicians benefited from musicians' expertise without negatively influencing musicians' ability to maintain the tapping rate. One implication is that nonmusicians may improve their beat-keeping abilities by performing tasks with musically skilled individuals.
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Estimulação Acústica , Percepção Auditiva/fisiologia , Retroalimentação Sensorial/fisiologia , Articulações/fisiologia , Destreza Motora/fisiologia , Música , Adolescente , Adulto , Feminino , Humanos , Masculino , Adulto JovemRESUMO
Coral growth anomalies (GAs) are chronic diseases that adversely affect organism health and fitness. We investigated immunity and fecundity within and among GA-affected and visually healthy control colonies of the reef-building coral Acropora hyacinthus. Compared to controls, GAs had higher activity of the key immunity enzyme phenoloxidase (PO), suggesting a localised immune response within the GA. Both GAs and healthy tissue of GA-affected colonies had significantly greater total potential PO (tpPO)-PO activity inclusive of the activated latent PO, prophenoloxidase-than control colonies. Higher tpPO activity in GA-affected corals suggests elevated constitutive immunity compared to visually healthy controls. Additionally, fewer GA-affected colonies produced gametes, fewer polyps had oocytes (p < 0.001) and the number of oocytes per polyp was lower. Therefore, GAs in A. hyacinthus might induce, or represent a shift in resource investment towards immunity and away from reproduction. While the effect on population growth is likely to be small, reduced fecundity in GA-affected colonies does suggest a selective pressure against GAs.
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Antozoários , Animais , Antozoários/crescimento & desenvolvimento , Recifes de Corais , FertilidadeRESUMO
Recent research suggests that perception and action are strongly interrelated and that motor experience may aid memory recognition. We investigated the role of motor experience in auditory memory recognition processes by musicians using behavioral, ERP, and neural source current density measures. Skilled pianists learned one set of novel melodies by producing them and another set by perception only. Pianists then completed an auditory memory recognition test during which the previously learned melodies were presented with or without an out-of-key pitch alteration while the EEG was recorded. Pianists indicated whether each melody was altered from or identical to one of the original melodies. Altered pitches elicited a larger N2 ERP component than original pitches, and pitches within previously produced melodies elicited a larger N2 than pitches in previously perceived melodies. Cortical motor planning regions were more strongly activated within the time frame of the N2 following altered pitches in previously produced melodies compared with previously perceived melodies, and larger N2 amplitudes were associated with greater detection accuracy following production learning than perception learning. Early sensory (N1) and later cognitive (P3a) components elicited by pitch alterations correlated with predictions of sensory echoic and schematic tonality models, respectively, but only for the perception learning condition, suggesting that production experience alters the extent to which performers rely on sensory and tonal recognition cues. These findings provide evidence for distinct time courses of sensory, schematic, and motoric influences within the same recognition task and suggest that learned auditory-motor associations influence responses to out-of-key pitches.
Assuntos
Percepção Auditiva/fisiologia , Encéfalo/fisiologia , Aprendizagem/fisiologia , Música , Reconhecimento Fisiológico de Modelo/fisiologia , Reconhecimento Psicológico/fisiologia , Eletroencefalografia , Potenciais Evocados , Feminino , Humanos , Masculino , Testes Neuropsicológicos , Competência Profissional , Adulto JovemRESUMO
Sounds that have been produced with one's own motor system tend to be remembered better than sounds that have only been perceived, suggesting a role of motor information in memory for auditory stimuli. To address potential contributions of the motor network to the recognition of previously produced sounds, we used event-related potential, electric current density, and behavioral measures to investigate memory for produced and perceived melodies. Musicians performed or listened to novel melodies, and then heard the melodies either in their original version or with single pitch alterations. Production learning enhanced subsequent recognition accuracy and increased amplitudes of N200, P300, and N400 responses to pitch alterations. Premotor and supplementary motor regions showed greater current density during the initial detection of alterations in previously produced melodies than in previously perceived melodies, associated with the N200. Primary motor cortex was more strongly engaged by alterations in previously produced melodies within the P300 and N400 timeframes. Motor memory traces may therefore interface with auditory pitch percepts in premotor regions as early as 200 ms following perceived pitch onsets. Outcomes suggest that auditory-motor interactions contribute to memory benefits conferred by production experience, and support a role of motor prediction mechanisms in the production effect.
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Encéfalo/fisiologia , Aprendizagem/fisiologia , Atividade Motora/fisiologia , Reconhecimento Fisiológico de Modelo/fisiologia , Percepção da Altura Sonora/fisiologia , Estimulação Acústica , Mapeamento Encefálico , Eletroencefalografia , Potenciais Evocados , Feminino , Humanos , Masculino , Música , Testes Neuropsicológicos , Competência Profissional , Adulto JovemRESUMO
Music performance requires precise control of limb movements in order to achieve temporal precision of performed tone onsets. Previous findings suggest that processes recruited for the temporal control of rhythmic body movements, such as those required in music performance, depend on the movement type (discrete vs. continuous) and the rate of the produced interonset intervals (sub-second vs. supra-second). Using a dual-task paradigm, the current study addressed these factors in the temporal control of cellists' bowing movements. Cellists performed melodies in a synchronization-continuation timing task at a specified fast (intertone interval = 700 ms) or slow (intertone interval = 1,100 ms) tempo with either discrete (staccato) or continuous (legato) bowing movements. A secondary working memory task involved a concurrent digit-switch counting task. Analyses of the produced tone durations showed that the working memory load significantly impaired temporal regularity when the melodies were performed with discrete bowing movements at the slower tempo. In addition, discrete movements led to more errors on the working memory task. These findings suggest that continuous body movements provide temporal control information to performers under high cognitive load conditions.
Assuntos
Memória de Curto Prazo/fisiologia , Movimento/fisiologia , Desempenho Psicomotor/fisiologia , Adulto , Feminino , Humanos , Masculino , Música , Adulto JovemRESUMO
Many behaviors require that individuals coordinate the timing of their actions with others. The current study investigated the role of two factors in temporal coordination of joint music performance: differences in partners' spontaneous (uncued) rate and auditory feedback generated by oneself and one's partner. Pianists performed melodies independently (in a Solo condition), and with a partner (in a duet condition), either at the same time as a partner (Unison), or at a temporal offset (Round), such that pianists heard their partner produce a serially shifted copy of their own sequence. Access to self-produced auditory information during duet performance was manipulated as well: Performers heard either full auditory feedback (Full), or only feedback from their partner (Other). Larger differences in partners' spontaneous rates of Solo performances were associated with larger asynchronies (less effective synchronization) during duet performance. Auditory feedback also influenced temporal coordination of duet performance: Pianists were more coordinated (smaller tone onset asynchronies and more mutual adaptation) during duet performances when self-generated auditory feedback aligned with partner-generated feedback (Unison) than when it did not (Round). Removal of self-feedback disrupted coordination (larger tone onset asynchronies) during Round performances only. Together, findings suggest that differences in partners' spontaneous rates of Solo performances, as well as differences in self- and partner-generated auditory feedback, influence temporal coordination of joint sensorimotor behaviors.
Assuntos
Retroalimentação Sensorial/fisiologia , Música , Periodicidade , Percepção da Altura Sonora/fisiologia , Desempenho Psicomotor/fisiologia , Percepção do Tempo/fisiologia , Estimulação Acústica , Adaptação Fisiológica , Adolescente , Adulto , Feminino , Humanos , Masculino , Estatística como Assunto , Adulto JovemRESUMO
In recent years, the Minnesota Attorney General's Office and the Minnesota Department of Health have cultivated a productive partnership to strengthen the state's multidisciplinary response to overlapping health equity and social justice issues. This article describes shared efforts in three areas: post-conviction justice, drug overdose, and human trafficking/exploitation.
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Overdose de Drogas , Minnesota , Humanos , Overdose de Drogas/prevenção & controle , Governo Estadual , Advogados , Justiça Social , Equidade em SaúdeRESUMO
Successful music-making requires precise sensorimotor synchronization, both in individual (solo) and joint (ensemble) social settings. We investigated how individual practice synchronizing with a temporally regular melody (Solo conditions) influences subsequent synchronization between two partners (Joint conditions). Musically trained adults practiced producing a melody by tapping on a keypad; each tap generated the next tone in the melody. First, the pairs synchronized their melody productions with their partner in a baseline Joint synchronization task. Then each partner separately synchronized their melody with a computer-generated recording of the partner's melody in a Solo intervention condition that presented either Normal (temporally regular) auditory feedback or delayed feedback (by 30-70 ms) in occasional (25%) randomly placed tone positions. Then the pairs synchronized again with their partner in a Joint condition. Next, they performed the second Solo condition (normal or delayed auditory feedback) followed again by the Joint condition. Joint synchronization performance was modeled with a delay-coupled oscillator model to assess the coupling strength between partners. Absolute asynchronies in the Solo Intervention tasks were greater in the Delayed feedback condition than in the Normal feedback condition. Model estimates yielded larger coupling values between partners in Joint conditions that followed the Solo Normal feedback than the Solo Delayed feedback. Notably, the asynchronies were smaller in the Joint conditions than in the Solo conditions. These findings indicate that coupled interactions in settings of two or more performers can be improved by individual synchronization practice.
RESUMO
Humans' complex behavior, such as speech, music, or dance, requires us to coordinate our actions with external sounds as well as with social partners. The presence of a partner can influence individuals' synchronization, and, in turn, social connection with the partner may depend on the degree of synchronization. We manipulated the synchronization quality in intervention conditions to address the causal relationship between observed temporal synchrony and perceived social interaction. Pairs of musician and nonmusician participants first performed a turn-taking task consisting of alternating which partner tapped their melody in synchrony with a metronome (each tap generated the next tone in the melody). In two intervention conditions, participants attempted to synchronize their melodies simultaneously with their partner, either with normal auditory feedback (normal feedback) or randomly placed delayed feedback on 25% of melodic tones (delayed feedback). After each intervention, the turn-taking condition was repeated, and participants completed a questionnaire about connectedness, relationship, and feeling of synchronization with their partner. Results showed that partners' mean asynchronies were more negative following the delayed feedback intervention. In addition, nonmusician partners' tapping variability was larger following the delayed feedback intervention when they had the delayed feedback intervention first. Ratings of connectedness, relationship, and feeling of synchronization with their partner were reduced for all participants after the delayed feedback Intervention. We modeled participants' synchronization performance in the post-intervention turn-taking conditions using delay-coupling oscillator models. Reductions in synchronization performance after delayed feedback intervention were reflected in reduced coupling strength. These findings suggest that turn-taking synchronization performance and social connectedness are altered following short interventions that disrupt synchronization with a partner.
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Música , Interação Social , Humanos , Masculino , Feminino , Música/psicologia , Adulto , Adulto Jovem , Percepção Auditiva/fisiologia , Relações InterpessoaisRESUMO
Socio-demographic inequities in health treatment and outcomes are not new. However, the COVID-19 pandemic presented new opportunities to examine and address biases. This article describes a scoping review of 170 papers published prior to the onset of global vaccinations and treatment (December 2021). We report differentiated COVID-19-related patient outcomes for people with various socio-demographic characteristics, including the need for intubation and ventilation, intensive care unit admission, discharge to hospice care, and mortality. Using the PROGRESS-Plus framework, we determined that the most researched socio-demographic factor was race/ethnicity/culture/language. Members of minoritized racial and ethnic groups tended to have worse COVID-19-related patient outcomes; more research is needed about other categories of social disadvantage, given the scarcity of literature on these factors at the time of the review. It is only by researching and addressing the causes of social disadvantage that we can avoid such injustice in future public health crises.
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COVID-19 , Humanos , COVID-19/epidemiologia , COVID-19/etnologia , Fatores Sociodemográficos , Fatores Socioeconômicos , Desigualdades de SaúdeRESUMO
BACKGROUND: Extracorporeal membrane oxygenation (ECMO) represents an important but limited treatment for patients with severe COVID-19. We assessed the effects of an educational intervention on a person's ECMO care preference and examined whether patients and providers had similar ECMO preferences. METHODS: In the Video+Survey group, patients watched an educational video about ECMO's purpose, benefits, and risks followed by an assessment of ECMO knowledge and care preferences in seven scenarios varying by hypothetical patient age, function, and comorbidities. Patients in the Survey Only group and providers didn't watch the video. Logistic regression was used to estimate the probability of agreement for each ECMO scenario between the two patient groups and then between all patients and providers. RESULTS: Video+Survey patients were more likely (64% vs. 17%; p = 0.02) to correctly answer all ECMO knowledge questions than Survey Only patients. Patients in both groups agreed that ECMO should be considered across all hypothetical scenarios, with predicted agreement above 65%. In adjusted analyses, patients and providers had similar predicted agreement for ECMO consideration across six of the seven scenarios, but patients showed greater preference (84% vs. 41%, p = 0.003) for the scenario of a functionally dependent 65-year-old with comorbidities than providers. DISCUSSION AND CONCLUSIONS: An educational video increased a person's ECMO knowledge but did not change their ECMO preferences. Clinicians were less likely than patients to recommend ECMO for older adults, so advanced care planning discussion between patients and providers about treatment options in critically ill patients with COVID-19 is critical.
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COVID-19 , Oxigenação por Membrana Extracorpórea , Educação de Pacientes como Assunto , Preferência do Paciente , Humanos , COVID-19/terapia , COVID-19/epidemiologia , Masculino , Feminino , Pessoa de Meia-Idade , Adulto , Educação de Pacientes como Assunto/métodos , Idoso , Inquéritos e Questionários , SARS-CoV-2 , Pessoal de Saúde/psicologia , Conhecimentos, Atitudes e Prática em SaúdeRESUMO
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.
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Córtex Auditivo/fisiologia , Música , Inibição Neural/fisiologia , Percepção da Altura Sonora/fisiologia , Percepção do Tempo/fisiologia , Estimulação Acústica/métodos , Adolescente , Adulto , Mapeamento Encefálico/métodos , Feminino , Lobo Frontal/fisiologia , Humanos , Imageamento por Ressonância Magnética , Masculino , Córtex Motor/fisiologia , Lobo Parietal/fisiologia , Desempenho Psicomotor/fisiologia , Adulto JovemRESUMO
Glyphosate-based herbicides are among the leading products used in South Africa to control weeds and invading alien plant species. Although these herbicides ultimately find their way into aquatic ecosystems, South Africa has no water quality guideline based on indigenous species to protect the country's aquatic biota against these biocides. In this study, South African water quality guidelines (SAWQGs) for Roundup(®) based on species sensitivity distribution (SSD) using indigenous aquatic biota were developed. Short-term and long-term toxicity tests were conducted with eight different aquatic species belonging to five different taxonomic groups. Static non-renewal experimental methods were employed for short-term lethal tests (≤4 days), and static renewal for long-term sublethal tests (≥4 days ≤21 days). LC50 values for animal exposure and EC50 values for algae were calculated using probit analysis and linear regression of transformed herbicide concentration as natural logarithm data against percentage growth inhibition, respectively. No effect concentration (NEC) was determined based on the dynamic energy budget model, using survival data. The LC50, EC50 and NEC values were used to develop species sensitivity distribution (SSD) concentrations for Roundup(®). Based on the SSD concentrations, the short-term and long-term SAWQGs for Roundup(®) were derived as 0.250 (0.106-0.589) mg/L, and 0.002 (0.000-0.021) mg/L, respectively. These WQGs may be useful in protecting South African aquatic life against transient or long-term exposure to glyphosate-based chemicals as part of integrated water resources management.
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Peixes/fisiologia , Glicina/análogos & derivados , Invertebrados/efeitos dos fármacos , Plantas/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Qualidade da Água , Animais , Água Doce , Glicina/toxicidade , Guias como Assunto , Dose Letal Mediana , África do Sul , Testes de Toxicidade , GlifosatoRESUMO
Accurate perception and production of auditory rhythms are key for human behaviors such as speech and music. Auditory rhythms in music range in their complexity: complex rhythms (based on non-integer ratios between successive tone durations) are more difficult to perceive and produce than simple rhythms (based on integer ratios). The physiological activity supporting this behavioral difference is not well understood. In a within-subjects design, we addressed how rhythm complexity affects cardiac dynamics during auditory perception and production. Musically trained adults listened to and synchronized with simple and complex auditory rhythms while their cardiac activity was recorded. Participants identified missing tones in the rhythms during the Perception condition and tapped on a keyboard to synchronize with the rhythms in the Synchronization condition. Participants were equally accurate at identifying missing tones in simple and complex rhythms during the Perception condition. Tapping synchronization was less accurate and less precise with complex rhythms than with simple rhythms. Linear cardiac analyses showed a slower mean heart rate and greater heart rate variability during perception than synchronization for both simple and complex rhythms; only nonlinear recurrence quantification analyses reflected cardiac differences between simple and complex auditory rhythms. Nonlinear cardiac dynamics were also more deterministic (predictable) during rhythm perception than synchronization. Individual differences during tapping showed that greater heart rate variability was correlated with poorer synchronization. Overall, these findings suggest that linear measures of musicians' cardiac activity reflect global task variability while nonlinear measures additionally reflect stimulus rhythm complexity.
Assuntos
Música , Transtornos da Percepção , Adulto , Humanos , Percepção Auditiva/fisiologia , Desempenho Psicomotor/fisiologia , Estimulação AcústicaRESUMO
Synchronization, the human tendency to align behaviors in time with others, is necessary for many survival skills. The ability to synchronize actions with rhythmic (predictable) sound patterns is especially well developed in music making. Recent models of synchrony in musical ensembles rely on pairwise comparisons between group members. This pairwise approach to synchrony has hampered theory development, given current findings from social dynamics indicating shifts in members' influence within larger groups. We draw on social theory and nonlinear dynamics to argue that emergent properties and novel roles arise in musical group synchrony that differ from individual or pairwise behaviors. This transformational shift in defining synchrony sheds light on successful outcomes as well as on disruptions that cause negative behavioral outcomes.
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Amphibians are the most threatened species-rich vertebrate group, with species extinctions and population declines occurring globally, even in protected and seemingly pristine habitats. These 'enigmatic declines' are generated by climate change and infectious diseases. However, the consequences of these declines are undocumented as no baseline ecological data exists for most affected areas. Like other neotropical countries, Costa Rica, including Área de Conservación Guanacaste (ACG) in north-western Costa Rica, experienced rapid amphibian population declines and apparent extinctions during the past three decades. To delineate amphibian diversity patterns within ACG, a large-scale comparison of multiple sites and habitats was conducted. Distance and time constrained visual encounter surveys characterised species richness at five sites-Murciélago (dry forest), Santa Rosa (dry forest), Maritza (mid-elevation dry-rain forest intersect), San Gerardo (rainforest) and Cacao (cloud forest). Furthermore, species-richness patterns for Cacao were compared with historic data from 1987-8, before amphibians declined in the area. Rainforests had the highest species richness, with triple the species of their dry forest counterparts. A decline of 45% (20 to 11 species) in amphibian species richness was encountered when comparing historic and contemporary data for Cacao. Conservation efforts sometimes focus on increasing the resilience of protected areas, by increasing their range of ecosystems. In this sense ACG is unique containing many tropical ecosystems compressed in a small geographic space, all protected and recognised as a UNESCO world heritage site. It thus provides an extraordinary platform to understand changes, past and present, and the resilience of tropical ecosystems and assemblages, or lack thereof, to climate change.