GABA能抑制参与弱噪声对下丘频率调谐的前掩蔽

在自由声场条件下，选用强度相当于纯音阈上5dB SPL、80ms的弱包络白噪声作为前掩蔽声，观察加入掩蔽声后神经元频率调谐的变化．对发生锐化的神经元导入荷包牡丹碱（Bicuculline，BIC），观察去GABA能抑制后前掩蔽效应的变化．结果显示：弱噪声前掩蔽使大部分神经元的频率调谐曲线（frequency tuning curve，FTC）锐化（P〈0．01），导入BIC后，弱噪声的抑制率下降．研究结果证实GABA能抑制参与了弱噪声所致的下丘神经元前掩蔽．

Involvement of GABAergic inhibition in forward masking induced by weak noise on frequency tuning of inferior colliculus

To study the effect of GABAergic inhibition on forward masking of weak noise and the mechanism underlying this temporal integration,this paper use weak white noise which is relative to 5 dB beyond minimum threshold(reMT+5) and 80 ms as forward masker.Under free field stimulation conditions,the changes in neuronal frequency tuning resulted from forward masking sound are examined.In addition, the paper observes the effect of micro-ionophoresis of BIC to the sharpened neurons,and finds that forward masking sharpens frequency tuning curves(FTCs) of most neurons(P<0.01).After micro-ionophoresis of BIC,the inhibitory rate of weak noise decreases.It's believed that the GABAergic inhibition is involved in forward masking induced by weak white noise on the inferior colliculus.