Familiarity overrides complexity in rhythm perception: a cross-cultural comparison of American and Turkish listeners.

Despite the ubiquity of dancing and synchronized movement to music, relatively few studies have examined cognitive representations of musical rhythm and meter among listeners from contrasting cultures. We aimed to disentangle the contributions of culture-general and culture-specific influences by examining American and Turkish listeners' detection of temporal disruptions (varying in size from 50-250 ms in duration) to three types of stimuli: simple rhythms found in both American and Turkish music, complex rhythms found only in Turkish music, and highly complex rhythms that are rare in all cultures. Americans were most accurate when detecting disruptions to the simple rhythm. However, they performed less accurately but comparably in both the complex and highly complex conditions. By contrast, Turkish participants performed accurately and indistinguishably in both simple and complex conditions. However, they performed less accurately in the unfamiliar, highly complex condition. Together, these experiments implicate a crucial role of culture-specific listening experience and acquired musical knowledge in rhythmic pattern perception.

Time course and nature of brain atrophy in the MRL mouse model of central nervous system lupus.

OBJECTIVE: Similar to patients with systemic lupus erythematosus, autoimmune MRL/lpr mice spontaneously develop behavioral deficits and pathologic changes in the brain. Given that the disease-associated brain atrophy in this model is not well understood, the present study was undertaken to determine the time course of morphometric changes in major brain structures of autoimmune MRL/lpr mice. METHODS: Computerized planimetry and high-resolution magnetic resonance imaging (MRI) were used to compare the areas and volumes of brain structures in cohorts of mice that differ in severity of lupus-like disease. RESULTS: A thinner cerebral cortex and smaller cerebellum were observed in the MRL/lpr substrain, even before severe autoimmunity developed. With progression of the disease, the brain area of coronal sections became smaller and the growth of the hippocampus was retarded, which likely contributed to the increase in the ventricle area:brain area ratio. MRI revealed reduced volume across different brain regions, with the structures in the vicinity of the ventricular system particularly affected. The superior colliculus, periaqueductal gray matter, pons, and midbrain were among the regions most affected, whereas the volumes of the parietal-temporal lobe, parts of the cerebellum, and lateral ventricles in autoimmune MRL/lpr mice were comparable with values in congenic controls. CONCLUSION: These results suggest that morphologic alterations in the brains of MRL/lpr mice are a consequence of several factors, including spontaneous development of lupus-like disease. A periventricular pattern of parenchymal damage is consistent with the cerebrospinal fluid neurotoxicity, limbic system pathologic features, and deficits in emotional reactivity previously documented in this model.