Global versus local processing of frequency-modulated tones in gerbils: An animal model of lateralized auditory cortex functions
Global versus local processing of frequency-modulated tones in gerbils: An animal model of lateralized auditory cortex functions
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DOI：
10.1073/pnas.0707844105
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发表时间：
2008-05-06
影响因子：
11.1
通讯作者：
Scheich, Henning
中科院分区：
文献类型：
--
作者：
Wetzel, Wolfram;Ohl, Frank W.;Scheich, Henning
语音和音乐处理的半球不对称性可能源于左右听觉皮层（AC）的更基本的专门化。然而，尚不清楚这种不对称是否是人类独有的，即，语音和音乐的后果，或类似的侧AC功能是否存在于非人类动物，作为进化的前体。在这里，我们研究了在沙鼠，啮齿类动物与人类一样的低频听觉的线性调频（FM）音的感知皮层偏侧化。在178只沙鼠中使用了一个加强了足震的梭箱回避去/不去程序，我们发现：（i）连续FM的方向辨别（上升扫描与下降扫描，持续时间250 ms）受到右侧而非左侧AC病变的损害;（ii）分段调频的方向判别（50 ms节段，50 ms无声间隙，总持续时间250 ms）受到双侧而非单侧AC病变的损害;（拟合）节段性FM的间隙持续时间（10-30 ms）的辨别力被左侧而非右侧AC病变损害。训练前后的AC损伤产生了类似的效果。总之，这些实验表明，右和左AC，即使在啮齿动物中，使用不同的策略来分析FM刺激。因此，正确的AC，通过使用全局线索，确定连续和分段FM的方向，但不能区分间隙持续时间。左AC，通过使用本地线索，辨别间隙持续时间，并确定FM方向时，只有额外的分段信息是可用的。
Hemispheric asymmetries of speech and music processing might arise from more basic specializations of left and right auditory cortex (AC). It is not clear, however, whether such asymmetries are unique to humans, i.e., consequences of speech and music, or whether comparable lateralized AC functions exist in nonhuman animals, as evolutionary precursors. Here, we investigated the cortical lateralization of perception of linearly frequency-modulated (FM) tones in gerbils, a rodent species with human-like low-frequency hearing. Using a footshock-reinforced shuttle-box avoidance go/no-go procedure in a total of 178 gerbils, we found that (i) the discrimination of direction of continuous FM (rising versus falling sweeps, 250-ms duration) was impaired by right but not left AC lesions; (ii) the discrimination of direction of segmented FM (50-ms segments, 50-ms silent gaps, total duration 250 ms) was impaired by bilateral but not unilateral AC lesions; (fit) the discrimination of gap durations (10-30 ms) in segmented FM was impaired by left but not right AC lesions. AC lesions before and after training resulted in similar effects. Together, these experiments suggest that right and left AC, even in rodents, use different strategies in analyzing FM stimuli. Thus, the right AC, by using global cues, determines the direction of continuous and segmented FM but cannot discriminate gap durations. The left AC, by using local cues, discriminates gap durations and determines FM direction only when additional segmental information is available.