Carlson S, Willott J F
Department of Psychology, Northern Illinois University, DeKalb 60115, USA.
Hear Res. 1996 Sep 15;99(1-2):168-75. doi: 10.1016/s0378-5955(96)00098-6.
Adult C57BL/6J mice exhibit high-frequency, sensorineural hearing loss accompanied by physiological changes in the upper auditory brainstem and cortex, referred to as hearing-loss induced (HLI) plasticity: as high-frequency sensitivity declines, many neurons come to respond better to still-audible, middle-frequency tones (especially 12-16 kHz). We used prepulse inhibition (PPI) to assess the relationship between the behavioral salience of tones and HLI plasticity. The ability of a tone 'prepulse' (S1), presented 100 ms before a startle-eliciting tone (S2), to 'inhibit' startle responses was measured in normal-hearing 1-month-olds and 5-month-olds with high-frequency hearing loss. Tone bursts of 4, 8, 12, 16, and 24 kHz were used as S1s and S2s in all possible combinations. PPI was significantly improved (more inhibition) in 5-month-olds with 12 or 16 kHz S1s. This effect was not influenced by S2 frequency or the size of the startle evoked by S2-only stimuli (smaller for high-frequency S2s in older mice). The increased salience of 12-16 kHz S1s in 5-month-old C57 mice parallels changes in the central representation of tone frequency and implies a behavioral effect of HLI plasticity.
成年C57BL/6J小鼠表现出高频感音神经性听力损失，并伴有听觉脑干上部和皮层的生理变化，这被称为听力损失诱导（HLI）可塑性：随着高频敏感性下降，许多神经元对仍能听到的中频音调（尤其是12 - 16千赫）反应更好。我们使用预脉冲抑制（PPI）来评估音调的行为显著性与HLI可塑性之间的关系。在听力正常的1月龄和高频听力损失的5月龄小鼠中，测量在引发惊吓的音调（S2）之前100毫秒呈现的音调“预脉冲”（S1）“抑制”惊吓反应的能力。4、8、12、16和24千赫的音爆被用作S1和S2的所有可能组合。在使用12千赫或16千赫S1的5月龄小鼠中，PPI显著改善（抑制作用更强）。这种效应不受S2频率或仅由S2刺激引发的惊吓大小的影响（老年小鼠中高频S2引发的惊吓较小）。5月龄C57小鼠中12 - 16千赫S1显著性的增加与音调频率的中枢表征变化相似，并暗示了HLI可塑性的行为效应。
