Amplitude- and duration-sensitivity of single-on and double-on neurons to CF-FM stimuli in inferior colliculus of Pratt's roundleaf bat (Hipposideros pratti).

During hunting, the duration and amplitude of bat's echolocation sounds co-vary. Our previous studies showed the inferior collicular neurons of constant frequency-frequency modulation (CF-FM) bat discharged as single-on (SO) or double-on (DO) responders when stimulated with behavior related CF-FM sounds. However, how the co-varied sound duration and amplitude modulate the response properties of SO and DO neurons were understudied. Therefore, we investigated amplitude- and duration-sensitivity in 121 neurons isolated in the inferior colliculus of CF-FM bat, Pratt's roundleaf bat (Hipposideros pratti). Responses of SO and DO neurons were obtained by in vivo intracellular recordings and examined for different stimulus amplitudes and durations. Our results revealed that response patterns of SO neurons were unaffected by changes in amplitude and duration of CF-FM stimuli. However, the excitability of DO neurons increased with prolonged CF duration and higher amplitude of CF-FM stimuli. These data suggested that the invariance of SO neurons play a key role in detection of Doppler shift and glint-like changes of frequency and amplitude induced by wingbeats of insects. In contrast, amplitude- and duration-sensitivity of DO neurons to CF-FM stimuli is consistent with the systematic changes in these signal parameters during sequential phases of foraging in CF-FM bats.

Latency modulation of collicular neurons induced by electric stimulation of the auditory cortex in Hipposideros pratti: In vivo intracellular recording.

In the auditory pathway, the inferior colliculus (IC) receives and integrates excitatory and inhibitory inputs from the lower auditory nuclei, contralateral IC, and auditory cortex (AC), and then uploads these inputs to the thalamus and cortex. Meanwhile, the AC modulates the sound signal processing of IC neurons, including their latency (i.e., first-spike latency). Excitatory and inhibitory corticofugal projections to the IC may shorten and prolong the latency of IC neurons, respectively. However, the synaptic mechanisms underlying the corticofugal latency modulation of IC neurons remain unclear. Thus, this study probed these mechanisms via in vivo intracellular recording and acoustic and focal electric stimulation. The AC latency modulation of IC neurons is possibly mediated by pre-spike depolarization duration, pre-spike hyperpolarization duration, and spike onset time. This study suggests an effective strategy for the timing sequence determination of auditory information uploaded to the thalamus and cortex.

Association of the C47T polymorphism in superoxide dismutase gene 2 with noise-induced hearing loss: a meta-analysis / Associação do polimorfismo C47T no gene da superóxido dismutase 2 com perda auditiva induzida pelo ruído: metanálise

Abstract Introduction Currently, there is limited information about the relationship between manganese superoxide dismutase (sod2) c47t polymorphism and susceptibility to noise-induced hearing loss (NIHL). Objective The aim of this meta-analysis was to clarify the association between SOD2 C47T polymorphism and NIHL. Methods A search in PubMed and Web of Science was performed to collect data. All full-text, English-written studies containing sufficient and complete case-and-control data about the relationship between SOD2 C47T polymorphism and NIHL were included. Three eligible studies, comprising 1094 subjects, were identified. pooled odds ratios (ORs) and 95% confidence intervals (CI) were calculated to evaluate the strength of the association between SOD2 C47T polymorphism and NIHL. Results No significant association between C47T polymorphism and risk of NIHL was found with the following combinations: T vs. C (OR = 0.83; 95% CI = 0.63–1.09); TT vs. CC (OR = 0.49; 95% CI = 0.22–1.09); CT vs. CC (OR = 0.54; 95% CI = 0.25–1.17); TT vs. CC + CT (OR = 0.82; 95% CI = 0.50–1.32); CC vs. TT + TC (OR = 0.49; 95% CI = 0.23–1.04). However, in subgroup analysis, a significant association was found for TT vs. CC + CT (OR = 0.77; 95% CI = 0.42–1.41) in the Chinese population. Conclusion The present meta-analysis suggests that SOD2 C47T polymorphism is significantly associated with increased risk of NIHL in the Chinese population. Further large and well-designed studies are needed to confirm this association.

Resumo Introdução Atualmente, são limitadas as informações acerca da relação entre o polimorfismo C47T de superóxido dismutase 2 (SOD2) dependente de manganês e suscetibilidade à perda auditiva induzida pelo ruído (PAIR). Objetivo O objetivo desta metanálise foi esclarecer a associação entre o polimorfismo C47T de SOD2 e PAIR. Método Foram feitas buscas no PubMed e Web of Science para coleta de dados. Foram incluídos todos os estudos no idioma inglês, com dados suficientes e completos de casos e controles sobre a relação entre o polimorfismo C47T de SOD2 e PAIR. Foram identificados três estudos qualificados, que abrangeram 1.094 indivíduos. Foram calculadas as razões das chances (odds ratio, OR) acumuladas e intervalos de confiança (IC) de 95% para que fosse avaliada a potência da associação entre o polimorfismo C47T de SOD2 e PAIR. Resultados Não foi encontrada uma associação significativa entre o polimorfismo C47T de SOD2 e risco de PAIR com as seguintes combinações: T vs. C (OR = 0,83, IC 95% = 0,63-1,09); TT vs. CC (OR = 0,49, IC 95% = 0,22-1,09); CT vs. CC (OR = 0,54, IC 95% = 0,25-1,17); TT vs. CC + CT (OR = 0,82, IC 95% = 0,50-1,32); CC vs. TT + TC (OR = 0,49, IC 95% = 0,23-1,04). Contudo, na análise de subgrupo, foi encontrada uma associação significativa para TT vs. CC + CT (OR = 0,77, 95% CI = 0,42-1.41) na população chinesa. Conclusão A presente metanálise sugere que o polimorfismo C47T de SOD2 demonstra associação significativa com maior risco de PAIR na população chinesa. Há necessidade de novos estudos de grande porte bem concebidos, para confirmação dessa associação.

Association of the C47T polymorphism in superoxide dismutase gene 2 with noise-induced hearing loss: a meta-analysis.

INTRODUCTION: Currently, there is limited information about the relationship between manganese superoxide dismutase (sod2) c47t polymorphism and susceptibility to noise-induced hearing loss (NIHL). OBJECTIVE: The aim of this meta-analysis was to clarify the association between SOD2 C47T polymorphism and NIHL. METHODS: A search in PubMed and Web of Science was performed to collect data. All full-text, English-written studies containing sufficient and complete case-and-control data about the relationship between SOD2 C47T polymorphism and NIHL were included. Three eligible studies, comprising 1094 subjects, were identified. pooled odds ratios (ORs) and 95% confidence intervals (CI) were calculated to evaluate the strength of the association between SOD2 C47T polymorphism and NIHL. RESULTS: No significant association between C47T polymorphism and risk of NIHL was found with the following combinations: T vs. C (OR=0.83; 95% CI=0.63-1.09); TT vs. CC (OR=0.49; 95% CI=0.22-1.09); CT vs. CC (OR=0.54; 95% CI=0.25-1.17); TT vs. CC+CT (OR=0.82; 95% CI=0.50-1.32); CC vs. TT+TC (OR=0.49; 95% CI=0.23-1.04). However, in subgroup analysis, a significant association was found for TT vs. CC+CT (OR=0.77; 95% CI=0.42-1.41) in the Chinese population. CONCLUSION: The present meta-analysis suggests that SOD2 C47T polymorphism is significantly associated with increased risk of NIHL in the Chinese population. Further large and well-designed studies are needed to confirm this association.

Research of the ATPase's rotation catalysis stochastic transition dynamics.

In this paper, based on the structure of the ATPase and the master equation, we put forward a stochastic hopping model which describes the rotary four-state motor's dynamics action. Finally, we obtained the relationship of the angle velocity omega, diffusion coefficient and the ATP's concentration, and got a result which accords with the rotary motor's biological mechanism.