MECHANICAL, THERMAL, AND OPTICAL SIGNS OF EXCITATION IN THE NERVOUS SYSTEM

在本财政年度，我们进一步证明， 神经纤维和细胞的结构变化位于基底部， 神经兴奋的过程。 为此，我们研究了可兴奋的 由均匀的细胞成分组成的组织， 高度同步的方式，即鱼的电器官。 通过刺激 神经纤维进入电鳗，鲶鱼， 和射线，我们能够记录到不同的机械和热 表现在兴奋元素的结构变化， 机关 事实上，膨胀和温度上升的幅度， 在这些器官的兴奋过程中观察到的是10到100倍， 与以前记录的来自各种神经纤维和细胞的那些大。 特别重要的是我们发现了巨大的机械变化 与这些器官中的突触活动有关。 我们发现 众所周知的突触激活的电信号（即突触电位） 伴随着相对较大的膨胀和温度上升的 组织. 这些突触活动的早期迹象之后是一个缓慢， 但更大的膨胀（即表面的向外移动）， 器官. 这些发现有力地支持了我们的观点， 可兴奋组织的结构变化与 神经纤维和细胞表层的水分子。 此外，这些结果强烈表明，机械和 两栖动物脊髓和大脑的温度变化 先前描述的来自突触而不是来自神经 纤维

We have furnished, during this fiscal year, further proofs that rapid structural changes in the nerve fibers and cells lie at the base of the process of nerve excitation. To this end we have examined excitable tissues consisting of uniform cellular elements that can be excited in a highly synchronous manner, namely fish electric organs. By stimulating the nerve fibers entering the electric organs of electric eels, catfish and rays, we were able to record distinct mechanical and thermal manifestations of structural changes in the excitable elements in the organs. In fact, the magnitude of swelling and temperature rise which we have observed during excitation of these organs are 10 to 100 times as large as those recorded previously from various nerve fibers and cells. Particularly significant is our discovery of large mechanical changes associated with synaptic activity in these organs. We found that the well-known electric sign of synaptic activation (i.e. synaptic potential) is accompanied by relatively large swelling and temperature rise of the tissue. These early signs of synaptic activity are followed by a slow, but much larger swelling (i.e. an outward movement of the surface) of the organ. These findings offer a strong support to our view that the structural changes in excitable tissues are associated with movements of water molecules in the superficial layer of the nerve fibers and cells. Furthermore, these results strongly suggest that the mechanical and thermal changes in the amphibian spinal cord and brain which we have described previously arise from the synapses rather than from the nerve fibers.