幼年蝙蝠下丘神经元的听空间特性

AUDITORY SPACE REPRESENTATION IN THE INFERIOR COLLICULUS OF JUVENILE BAT,RHINOLOPHUS ROUXI

实验分别在出生后４周龄的幼年和成年鲁氏菊头蝠（Ｒｈｉｎｏｌｏｐｈｕｓｒｏｕｘｉ）上进行。使用移动声刺激装置，高频喇叭可在动物头部前方水平方向１８０度、垂直方向６０度的范围内移动。玻璃微电极记录单个神经元的听反应。实验考察了幼年和成年动物下丘神经元的听空间特性，共观察了３０１个神经元，其中幼年动物１４８个，成年动物１５３个。结果表明，４周龄的幼年动物下丘听神经元已表现出方向敏感性，即每个听神经元均有一个特定的最佳反应中心和反应域。但神经元听反应中心在听空间的分布相当弥散，大多数位于对侧水平方向２０—８０度、垂直方向上下１５度范围内。而成年动物听神经元反应中心的分布则相当集中，局限地分布于对侧水平方向２８－５０度，垂直方向０—１０度范围内，两者构成明显差异。

The auditory space representation of the inferior collicular(IC) neurons on the juvenile(postnatal 4th week)and adult rufors horseshoe bat,Rhinolophus rouxi was studied.148 and 153 IC nearons were isolated from the juvenile and adult bats respectively.The results demonstrate that the IC neurons of the juvenile had directional sensitivity,e.g.,each neuron has one best response center and spatial response area,but the response centers of neurons were rather scattered.The response centers of most IC neurons locate within contralateral 20-80°in azimuth,and 15°up and 15°down in elevation of the frontal auditory space.In contrast,the distribution of response centers of IC neurons in adult bat was more concentrated.The most respouse centers locate within contralateral 28-50°in azimuth,0-10°up in elevation.