Recanzone Gregg H, Beckerman Nathan S
Center for Neuroscience and Section of Neurobiology, Physiology and Behavior, University of California at Davis, Davis, CA 95616, USA.
Hear Res. 2004 Dec;198(1-2):116-24. doi: 10.1016/j.heares.2004.07.017.
Sound localization performance is degraded at low stimulus intensities in humans, and while the sound localization ability of humans and macaque monkeys appears similar, the effects of intensity have yet to be described in the macaque. We therefore defined the ability of four macaque monkeys to localize broadband noise stimuli at four different absolute intensities and six different starting locations in azimuth. Results indicate that performance was poorest at the lowest intensity tested (25 dB SPL), intermediate at 35 dB SPL, and equivalent at 55 and 75 dB SPL. Localization performance was best at 0 degree (directly in front of the animal) and was systematically degraded at more peripheral locations (+/-30 degrees and 90 degrees) and worst at a location directly behind the animal. Reaction times showed the same trends, with reaction times increasing with decreasing stimulus intensity, even under conditions where the monkey discriminated the location change with the same performance. These results indicate that sound level as well as position profoundly influences sound localization ability.
在人类中，声音定位能力在低刺激强度下会下降，虽然人类和猕猴的声音定位能力看起来相似，但强度对猕猴声音定位能力的影响尚未有描述。因此，我们确定了四只猕猴在四个不同绝对强度以及在方位角上六个不同起始位置定位宽带噪声刺激的能力。结果表明，在测试的最低强度（25 dB SPL）下表现最差，在35 dB SPL时处于中等水平，在55和75 dB SPL时相当。定位性能在0度（动物正前方）时最佳，在更外围的位置（±30度和90度）会系统性下降，在动物正后方的位置最差。反应时间呈现相同趋势，即使在猴子以相同表现辨别位置变化的条件下，反应时间也会随着刺激强度的降低而增加。这些结果表明，声级以及位置会深刻影响声音定位能力。
