Behavioral training promotes multiple adaptive processes following acute hearing loss.
Behavioral training promotes multiple adaptive processes following acute hearing loss.
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DOI：
10.7554/elife.12264
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发表时间：
2016-03-23
期刊：
影响因子：
7.7
通讯作者：
King AJ
中科院分区：
文献类型：
--
作者：
Keating P;Rosenior-Patten O;Dahmen JC;Bell O;King AJ
大脑拥有一种非凡的能力来补偿由一系列感官损伤引起的输入变化。声音定位的发展研究表明，对非对称性听力损失的适应可以通过重新解释改变的空间线索或更多地依赖于那些保持完整的线索来实现。成年后对单耳剥夺的适应也是可能的，但似乎缺乏这种灵活性。然而，在这里，我们表明，适当的行为训练，使monaurally-deprived成年人利用这两个适应过程。此外，不对称听力损失的雪貂的皮层记录表明，这些形式的可塑性有不同的神经基板。因此，不同的物种都有使用多种适应过程来适应非对称性听力损失的能力，并且可能在整个生命周期中持续存在。这突出了神经系统的基本灵活性，也可能指向治疗感觉障碍的新治疗策略。http://dx.doi.org/10.7554/eLife.12264.001大脑通常会比较到达每只耳朵的声音的时间和强度，以确定声音的来源。一只耳朵的听力损失会破坏这些耳朵之间的比较，这会导致听者在这个过程中犯错误。然而，随着时间的推移，大脑会适应这种听力损失，并再次学会准确定位声音。先前的研究表明，年轻的雪貂可以通过两种不同的方式适应一只耳朵的听力损失。雪貂要么学会将一只耳朵失去听力造成的耳间比较改变重新映射到新的位置。或者，雪貂学会只用它们的好耳朵定位声音。每种策略都适合定位不同类型的声音，但不知道这种适应性灵活性如何随着时间的推移而展开，它是否在整个生命周期中持续存在，或者它是否被其他物种共享。现在，基廷等人表明，经过一些训练，成年人也会使用同样的两种策略来适应一只耳朵的暂时性听力损失。在实验中，成年人被训练在一只耳朵戴着耳塞的情况下定位不同类型的声音。这些声音是由12个扬声器呈现的，这些扬声器围绕被测试的人水平地布置在一个圆圈中。实验表明，短期的行为训练可以使成年人适应一只耳朵的听力损失，并恢复他们定位声音的能力。就像雪貂一样，成年人学会了正确地将耳间比较的变化与他们的新位置联系起来，并更多地依赖于拔掉耳朵的线索来定位声音。参与者使用哪种适应策略取决于声音中存在的频率。耳朵和大脑中检测和感知声音的细胞通常对有限的频率范围做出最佳反应，因此这表明每种策略都依赖于一组不同的细胞。Keating等人在雪貂身上证实，不同的脑细胞确实被用来适应使用每种策略的一只耳朵的听力损失。这些见解可能有助于开发治疗听力损失的新疗法。DOI：http://dx.doi.org/10.7554/eLife.12264.002网站
The brain possesses a remarkable capacity to compensate for changes in inputs resulting from a range of sensory impairments. Developmental studies of sound localization have shown that adaptation to asymmetric hearing loss can be achieved either by reinterpreting altered spatial cues or by relying more on those cues that remain intact. Adaptation to monaural deprivation in adulthood is also possible, but appears to lack such flexibility. Here we show, however, that appropriate behavioral training enables monaurally-deprived adult humans to exploit both of these adaptive processes. Moreover, cortical recordings in ferrets reared with asymmetric hearing loss suggest that these forms of plasticity have distinct neural substrates. An ability to adapt to asymmetric hearing loss using multiple adaptive processes is therefore shared by different species and may persist throughout the lifespan. This highlights the fundamental flexibility of neural systems, and may also point toward novel therapeutic strategies for treating sensory disorders. DOI: http://dx.doi.org/10.7554/eLife.12264.001 The brain normally compares the timing and intensity of the sounds that reach each ear to work out a sound’s origin. Hearing loss in one ear disrupts these between-ear comparisons, which causes listeners to make errors in this process. With time, however, the brain adapts to this hearing loss and once again learns to localize sounds accurately. Previous research has shown that young ferrets can adapt to hearing loss in one ear in two distinct ways. The ferrets either learn to remap the altered between-ear comparisons, caused by losing hearing in one ear, onto their new locations. Alternatively, the ferrets learn to locate sounds using only their good ear. Each strategy is suited to localizing different types of sound, but it was not known how this adaptive flexibility unfolds over time, whether it persists throughout the lifespan, or whether it is shared by other species. Now, Keating et al. show that, with some coaching, adult humans also adapt to temporary loss of hearing in one ear using the same two strategies. In the experiments, adult humans were trained to localize different kinds of sounds while wearing an earplug in one ear. These sounds were presented from 12 loudspeakers arranged in a horizontal circle around the person being tested. The experiments showed that short periods of behavioral training enable adult humans to adapt to a hearing loss in one ear and recover their ability to localize sounds. Just like the ferrets, adult humans learned to correctly associate altered between-ear comparisons with their new locations and to rely more on the cues from the unplugged ear to locate sound. Which of these adaptive strategies the participants used depended on the frequencies present in the sounds. The cells in the ear and brain that detect and make sense of sound typically respond best to a limited range of frequencies, and so this suggests that each strategy relies on a distinct set of cells. Keating et al. confirmed in ferrets that different brain cells are indeed used to bring about adaptation to hearing loss in one ear using each strategy. These insights may aid the development of new therapies to treat hearing loss. DOI: http://dx.doi.org/10.7554/eLife.12264.002