Functional collumn of taste neurons in gustatory cortex in rats.

在前文中，我们描述了机械感受性神经元排列在大鼠初级味觉皮质(GC)的功能柱中(Wang和Ogawa，2002)，并且柱状直径的大小随接受特征的不同而变化。我们还注意到有证据表明，味觉神经元也可能类似地分布在那里，这取决于四种基本口味中最好的刺激。在本研究中，我们通过在大脑皮层表面插入不同角度的微电极，每隔50-100μm记录神经元的活动。我们还记录了味觉和机械感受性神经元的感受性特征(最佳刺激和感受野)。在组织重建的68个轨迹中，有49个记录到味觉神经元。平均每个成功的轨迹会遇到6.3个(1-16个)味觉神经元。然而，大多数轨迹中相继出现一个或两个味觉神经元，少数轨迹中恰好有5-6个味觉神经元相继出现。当连续记录两个或多个具有最佳刺激和感受场特性的味觉神经元时，通过在皮质表面投影记录位置的宽度来测量柱状尺寸，估计约为30μm，这与通过互相关分析估计的值是一致的(Nakamura and Ogawa，1997)。部分研究结果已提交给2004年7月在日本京都举行的嗅觉与味觉国际研讨会。

In the preceding paper, we described that mechanoreceptive neurons are arranged in a functional column in the primary gustatory cortex(GC) in rats(Wang and Ogawa,2002), and that the size of the columnar diameter varied depending on the receptive features. We also noted the evidence that gustatory neurons may similarly be arranged there, depending on the best stimulus among the four basic tastes. In the present study, we recorded neuronal activities every 50-100 μm by inserting microelectrodes to the cerebral cortex with various angles the cortical surface. We also characterized receptive features(best stimulus and receptive field) of taste and mechanoreceptive neurons recorded. Taste neurons were recorded at 49 of the 68 tracks histologically reconstructed. On average, 6.3(ranging 1-16) taste neurons were encountered every successful track. However, one or two taste neurons were successively encountered in most tracks, but 5-6 taste neurons happened to be encountered succesively in a few track. When two or more taste neurons sharing the best stimulus and receptive field properties in common were successively recorded, the columnar size was measured by projecting the width of the recording places on the cortical surfaces and was estimated about 30 μm. This size was compatible with the value estimated by cross-correlation analysis(Nakamura and Ogawa,1997). Parts of the results were presented to the International Symposium on Olfaction and Taste, held in Kyoto, Japan, in July,2004.