Higher-order projection interneurons that function in more than one behavior have been identified in a number of preparations. In this study, we document that stimulation of cell Tr1, a previously identified trigger interneuron for swimming in the medicinal leech, can also elicit the motor program for crawling in isolated nerve cords. We also show that motor choice is independent of the firing frequency of Tr1 and amount of spiking activity recorded extracellularly at three locations along the ventral nerve cord prior to Tr1 stimulation. On the other hand, during Tr1 stimulation there is a significant difference in the amount of activity elicited in the ventral nerve cord that correlates with the motor program activated. On average, Tr1 stimulation trials that lead to crawling elicit greater amounts of activity than in trials that lead to swimming.

中文翻译：

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通过先前确定的触发中间神经元激活两种形式的运动，用于在药用水蛭中游泳。

在许多准备工作中已经确定了在不止一种行为中起作用的高阶投射中间神经元。在这项研究中，我们记录了刺激细胞 Tr1（一种先前确定的用于在药用水蛭中游泳的触发中间神经元）也可以引发在孤立的神经索中爬行的运动程序。我们还表明，运动选择与 Tr1 的发射频率和在 Tr1 刺激之前沿腹神经索的三个位置在细胞外记录的刺激活动量无关。另一方面，在 Tr1 刺激期间，与激活的运动程序相关的腹神经索中引起的活动量存在显着差异。平均而言，导致爬行的 Tr1 刺激试验比导致游泳的试验引起更多的活动。