Arch-Tirado Emilio, Collado-Corona Miguel Angel, Morales-Martínez José de Jesús
Instituto de la Comunicación Humana, Area de Gobierno Cuerpo 8, Segundo piso, Centro Nacional de Rehavilitación, Calz. México-Xochimilco 289, Col. Arenal de Guadalupe, 14389 México DF.
Cir Cir. 2004 Jul-Aug;72(4):309-15.
amphibians, Frog catesbiana (frog bull, 30 animals); reptiles, Sceloporus torcuatus (common small lizard, 22 animals); birds: Columba livia (common dove, 20 animals), and mammals, Cavia porcellus, (guinea pig, 20 animals). With regard to lodging, all animals were maintained at the Institute of Human Communication Disorders, were fed with special food for each species, and had water available ad libitum. Regarding procedure, for carrying out analysis of auditory evoked potentials of brain stem SPL amphibians, birds, and mammals were anesthetized with ketamine 20, 25, and 50 mg/kg, by injection. Reptiles were anesthetized by freezing (6 degrees C). Study subjects had needle electrodes placed in an imaginary line on the half sagittal line between both ears and eyes, behind right ear, and behind left ear. Stimulation was carried out inside a no noise site by means of a horn in free field. The sign was filtered at between 100 and 3,000 Hz and analyzed in a computer for provoked potentials (Racia APE 78).
In data shown by amphibians, wave-evoked responses showed greater latency than those of the other species. In reptiles, latency was observed as reduced in comparison with amphibians. In the case of birds, lesser latency values were observed, while in the case of guinea pigs latencies were greater than those of doves but they were stimulated by 10 dB, which demonstrated best auditory threshold in the four studied species. Last, it was corroborated that as the auditory threshold of each species it descends conforms to it advances in the phylogenetic scale.
Beginning with these registrations, we care able to say that response for evoked brain stem potential showed to be more complex and lesser values of absolute latency as we advance along the phylogenetic scale; thus, the opposing auditory threshold is better agreement with regard to the phylogenetic scale among studied species. These data indicated to us that seeking of auditory information is more complex in more evolved species.
两栖动物，牛蛙（牛蛙，30只）；爬行动物，细纹强棱蜥（普通小蜥蜴，22只）；鸟类：家鸽（家鸽，20只），以及哺乳动物，豚鼠（豚鼠，20只）。关于饲养，所有动物均饲养于人类交流障碍研究所，用适合每个物种的特殊食物喂养，并随时提供饮水。关于实验步骤，为了进行脑干听觉诱发电位分析，两栖动物、鸟类和哺乳动物通过注射氯胺酮，分别以20、25和50mg/kg的剂量麻醉。爬行动物通过冷冻（6摄氏度）麻醉。研究对象在双耳与双眼之间的半矢状线上、右耳后方和左耳后方的假想线上放置针电极。在无噪音环境中通过自由场中的喇叭进行刺激。信号在100至3000Hz之间滤波，并在计算机上分析诱发电位（Racia APE 78）。
在两栖动物的数据中，波诱发反应的潜伏期比其他物种更长。在爬行动物中，与两栖动物相比，潜伏期缩短。在鸟类中，观察到潜伏期值较小，而在豚鼠中，潜伏期比鸽子长，但它们受到10dB的刺激，这表明在四个研究物种中豚鼠的听觉阈值最佳。最后，证实了随着每个物种听觉阈值的下降，其在系统发育尺度上的进化程度也随之提高。
从这些记录开始，我们可以说，随着我们在系统发育尺度上的推进，脑干诱发电位的反应变得更加复杂，绝对潜伏期的值更小；因此，在所研究的物种中，相对听觉阈值与系统发育尺度的一致性更好。这些数据向我们表明，在进化程度更高的物种中，对听觉信息的寻求更为复杂。
