Tonotopic organization and parcellation of auditory cortex in the FM-bat Carollia perspicillata
Tonotopic organization and parcellation of auditory cortex in the FM-bat Carollia perspicillata
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DOI：
10.1046/j.1460-9568.1999.00789.x
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发表时间：
1999-10-01
影响因子：
3.4
通讯作者：
Eiermann, A
中科院分区：
文献类型：
--
作者：
Esser, KH;Eiermann, A
在短尾果蝠的听觉皮层定位放射自显影和电生理的详细研究，通过使用金属微电极和10毫秒的音调刺激。因为，在弱麻醉的制备中，神经元对纯音的反应甚至在整个非初级听觉皮层中被发现，所以神经元簇（多单元）的特征频率和最小阈值可以被一致地映射，并用于传统地定义听觉皮层场（即：如在非回声定位哺乳动物的听觉皮层的研究中）。因此，在电生理学划分的听觉皮层内，六个听觉场由标准定义，例如特征频率的梯度初级听皮层;前听野;次级听觉皮层，AII），跨场边界的梯度反转（AI，AAF），有限频带的统一表示（即>60 kHz高频场I和II，HFI和HFII），以及从低到高的最小阈值过渡，反之亦然[背后场（DP），AII，HFI HFII]。作为这些听觉皮层领域的区别的支持性证据，神经元反应特性的差异也被使用。与其他哺乳动物（如猫和小鼠）相比，听觉场（主要是Al，AAF，DP和AII）的相对位置和这些前脑区域内的声音参数的代表原则似乎反映了哺乳动物听觉皮层组织的“基本计划”（下面讨论）。两个连贯的背位移高频表示（HFI，HFII）覆盖类似的40%的总听觉皮层表面似乎特别适合于处理占主导地位的生物声纳的第二和第三谐波的这个物种，因此可以被视为适应回声定位。
In the short-tailed fruit bat (Carollia perspicillata), the auditory cortex was localized autoradiographically and studied electrophysiologically in detail by using metal microelectrodes and 10-ms tone stimuli. Because, in the weakly-anaesthetized preparation, neuronal responses to pure-tones were even found throughout the non-primary auditory cortex, characteristic frequencies and minimum thresholds of neuron clusters (multiunits) could be mapped consistently and used to define auditory cortical fields conventionally (ie. as in studies of auditory cortex of non-echolocating mammals). Thus, within th electrophysiologically demarcated auditory cortex, six auditor fields were defined by criteria, as for example a gradient of characteristic frequencies (primary auditory cortex, Al; anterior auditory field; AAF; secondary auditory cortex, AII), reversal of the gradient across the field border (AI, AAF), uniform representation of a restricted band of frequencies (i.e. >60 kHz high-frequency fields I and II, HFI and HFII), and transition from low to high minimum threshold or vice versa [dorsoposterior field (DP), AII, HFI HFII]. As supportive evidence for the distinction of these auditory cortical fields, differences in neuronal response properties were also used. In comparison with other mammals (e.g. cat and mouse), both the relative position of the auditory fields (mainly Al, AAF, DP and AII) and the representational principles for sound parameters within these forebrain areas seem to reflect a 'fundamental plan' (discussion below) of mammalian auditory cortical organization. Two coherent dorsally displaced high-frequency representations (HFI, HFII) covering similar to 40% of the total auditory cortical surface seem particularly suited for the processing of the dominant biosonar second and third harmonic of this species, and hence can be regarded as an adaptation for echolocation.