Subjecting Elite Athletes to Inspiratory Breathing Load Reveals Behavioral and Neural Signatures of Optimal Performers in Extreme Environments

Background: It is unclear whether and how elite athletes process physiological or psychological challenges differently than healthy comparison subjects. In general, individuals optimize exercise level as it relates to differences between expected and experienced exertion, which can be conceptualized as a body prediction error. The process of computing a body prediction error involves the insular cortex, which is important for interoception, i.e. the sense of the physiological condition of the body. Thus, optimal performance may be related to efficient minimization of the body prediction error. We examined the hypothesis that elite athletes, compared to control subjects, show attenuated insular cortex activation during an aversive interoceptive challenge. Methodology/Principal Findings: Elite adventure racers (n = 10) and healthy volunteers (n = 11) performed a continuous performance task with varying degrees of a non-hypercapnic breathing load while undergoing functional magnetic resonance imaging. The results indicate that (1) non-hypercapnic inspiratory breathing load is an aversive experience associated with a profound activation of a distributed set of brain areas including bilateral insula, dorsolateral prefrontal cortex and anterior cingulated; (2) adventure racers relative to comparison subjects show greater accuracy on the continuous performance task during the aversive interoceptive condition; and (3) adventure racers show an attenuated right insula cortex response during and following the aversive interoceptive condition of non-hypercapnic inspirator

The effect of oxidation on the mineralogy and magnetic properties of olivine

Although nucleation of magnetite and/or hematite along dislocations upon oxidation of olivine has been observed by many workers, the effect of oxidation on the magnetic properties of the sample with specific mineralogical alterations has not been studied. Therefore, we investigate this problem using a set of time series 1 bar oxidation experiments at 600 and 900 °C. Results show rapid olivine oxidation and alteration at both 600 and 900 °C, forming magnetite and hematite associated with a change from paramagnetic to ferromagnetic behavior after oxidation. Magnetite and hematite nucleate along dislocations and impurities in the crystal structure, along with surface coatings and within cracks in the crystals. Fresh, unaltered mantle xenoliths containing magnetite have been interpreted as having formed in cold tectonic regimes in the mantle, rather than through oxidation during or after ascent. Mantle xenoliths rapidly ascend through the mantle with estimates of the ascent of up to 90 km/h (3 GPa/h) based on the diffusion profile of water in mantle olivine. The rates correspond to xenoliths ascending through the mantle over hours and not days or weeks. Our results show that olivine oxidation and alteration can occur in days to weeks at 600 °C and within minutes at 900 °C. Therefore, if the xenolithic material is transported to the surface in a cold magma (at temperatures ≤600 °C), then the timescale of ascent is likely not long enough for oxidation to cause magnetite formation or a ferromagnetic signature to occur. However, if the material is transported in a hot oxidized basaltic magma (with temperatures ≥900 °C), then oxidation can cause magnetite formation and a ferromagnetic signature

Combining functional scales and cognitive tests in screening for mild cognitive impairment at a university-based memory clinic in Brazil Combinação de escalas funcionais e testes cognitivos para rastreio de comprometimento cognitivo leve em ambulatório universitário de memória no Brasil

OBJECTIVE: To determine the diagnostic accuracy of the Mini-Mental State Examination combined to the Informant Questionnaire on Cognitive Decline in the Elderly for the identification of mild cognitive impairment. METHOD: 191 elderly subjects were assessed with the Mini-Mental State Examination, and their informants were assessed with the Informant Questionnaire on Cognitive Decline in the Elderly. Subjects were divided into three groups according to their cognitive state (controls: n = 67, mild cognitive impairment: n = 65 and dementia: n = 59), which was ascertained by clinical and neuropsychological evaluation. The diagnostic accuracy of each test in the discrimination of diagnostic groups (mild cognitive impairment vs. controls, mild cognitive impairment vs. dementia and dementia vs. controls) was examined with the aid of ROC curves. We additionally verified if the combination of both tests would increase diagnostic accuracy for mild cognitive impairment and control identification. RESULTS: The combination of the Mini-Mental State Examination and the Informant Questionnaire on Cognitive Decline in the Elderly scores did not increase the Mini-Mental State Examination diagnostic accuracy in the identification of patients with mild cognitive impairment. CONCLUSIONS: The present data do not warrant the combination of the Mini-Mental State Examination and the Informant Questionnaire on Cognitive Decline in the Elderly as a sufficient diagnostic tool in the diagnostic screening for mild cognitive impairment.<br>OBJETIVO: Avaliar a acurácia diagnóstica do Mini-Exame do Estado Mental combinado ao Questionário do Informante sobre Declínio Cognitivo na identificação de casos de comprometimento cognitivo leve. MÉTODO: 191 indivíduos idosos foram avaliados com o Mini-Exame do Estado Mental e seus informantes com o Questionário do Informante sobre Declínio Cognitivo. Os indivíduos foram divididos em três grupos de acordo com o estado cognitivo (controles: n = 67; comprometimento cognitivo leve: n = 65; demência: n = 59), segundo avaliação clínica e neuropsicológica. Pela análise de curvas ROC, avaliamos a acurácia diagnóstica de cada teste para diferenciar os grupos diagnósticos (comprometimento cognitivo leve vs. controles; comprometimento cognitivo leve vs. demência; demência vs. controles). Adicionalmente, verificamos se a combinação dos dois testes fortalece a acurácia diagnóstica para a separação dos casos de comprometimento cognitivo leve dos controles normais. RESULTADOS: A análise combinada do Questionário do Informante sobre Declínio Cognitivo e Mini-Exame do Estado Mental não aumentou a acurácia diagnóstica do Mini-Exame do Estado Mental em predizer a ocorrência de comprometimento cognitivo leve. CONCLUSÕES: Os dados deste estudo não sustentam a utilidade clínica da combinação dos escores do Mini-Exame do Estado Mental e do Questionário do Informante sobre Declínio Cognitivo no rastreio diagnóstico do comprometimento cognitivo leve

Combined instruments for the screening of dementia in older people with low Education Instrumentos combinados para o rastreio de demência em idosos com baixo nível educacional

OBJECTIVE: To determine which combination of cognitive tests and informant reports can improve the diagnostic accuracy of dementia screening in low educated older people. METHOD: Patients with mild to moderate dementia (n=34) according to ICD-10 and DSM-III-R criteria and 59 older controls were assessed with the Mini-Mental State Examination (MMSE) and the Fuld Object Memory Evaluation (FOME). Informants were assessed using the Informant Questionnaire on Cognitive Decline in the Elderly and the Bayer-Activities of Daily Living Scale. RESULTS: The 4 instruments combined with the mixed rule correctly classified 100% and the logistic regression (weighted sum) classified 95.7% of subjects. The weighted sum had a significantly larger ROC area compared to MMSE (p=0.008) and FOME (p=0.023). The specificity of the tested combinations was superior to the MMSE alone (p=0.002). CONCLUSIONS: Cognitive tests combined with informant reports can improve the screening of mild to moderate dementia in low educated older people.<br>OBJETIVO: Determinar qual combinação de testes cognitivos e avaliações do informante pode melhorar o rastreio de demência em idosos com baixo nível educacional. MÉTODO: Pacientes com demência leve a moderada (n=34) de acordo com critérios da CID-10 e DSM-III-R, e 59 controles idosos foram avaliados com o Mini-Exame do Estado Mental (MEEM) e com o "Fuld Object Memory Evaluation" (FOME). Informantes foram avaliados com o "Informant Questionnaire on Cognitive Decline in the Elderly" e a escala Bayer-Atividades da Vida Diária. RESULTADOS: Os quatro instrumentos combinados com a regra mista classificaram 100% e a regressão logística (soma ponderada) classificou 95,7% dos sujeitos. A soma ponderada teve uma área da curva ROC significativamente maior comparada ao MEEM (p=0,008) e FOME (p=0,023). A especificidade das combinações testadas foi superior ao MEEM isolado (p=0,002). CONCLUSÕES: Testes cognitivos combinados com relatos dos informantes podem melhorar o rastreio de demência leve a moderada em idosos com baixo nível educacional