Burrows M
J Neurosci. 1987 Apr;7(4):1064-80. doi: 10.1523/JNEUROSCI.07-04-01064.1987.
The connections made by afferents from a proprioceptor at the femorotibial joint in a hind leg of a locust, the femoral chordotonal organ (FCO), were determined by making intracellular recordings from motor neurons and spiking local interneurons in the central nervous system and from afferent cell bodies in the periphery. Staining the central projections of the afferent neurons with dye introduced into their axons at the receptor, and the intracellular injection of dye into motor neurons and interneurons, shows that the branches of all 3 types of neuron overlap in specific regions of neuropile. Afferents excited by a movement of the receptor apodeme that is equivalent to an imposed extension of the femorotibial joint excite flexor tibiae motor neurons and some spiking local interneurons with cell bodies at the ventral midline of the metathoracic ganglion. The opposite movement excites extensor tibiae motor neurons and a different set of spiking local interneurons. Spikes in afferents that excite flexor motor neurons evoke depolarizing potentials that follow each spike with a consistent central latency of approximately 1.5 msec. The amplitude of the depolarizing potentials is dependent upon the membrane potential of the motor neuron. This evidence points to the connection being direct and to the potentials' being EPSPs. Simultaneous recordings from certain spiking local interneurons and certain flexor motor neurons show that they receive many synaptic potentials in common and are driven in a parallel fashion by movements of the receptor apodeme. Spikes of some afferents evoke EPSPs in both neurons with the same consistency and latency. An afferent can therefore synapse directly upon a motor neuron and a spiking local interneuron. Each afferent synapses on several motor neurons and possibly upon several interneurons. In turn, each motor neuron and each interneuron receives inputs from several afferents.
通过对蝗虫后肢股胫关节处本体感受器——股弦音器（FCO）的传入纤维所形成的连接进行了测定，具体方法是在中枢神经系统中对运动神经元和发放冲动的局部中间神经元以及外周传入细胞体进行细胞内记录。将染料注入受体处传入神经元的轴突以标记其在中枢的投射，同时将染料细胞内注入运动神经元和中间神经元，结果显示这三种神经元的分支在神经纤维网的特定区域重叠。当受体腱膜的运动相当于股胫关节的被动伸展时，传入纤维兴奋，会激发胫节屈肌运动神经元以及一些细胞体位于后胸神经节腹中线的发放冲动的局部中间神经元。相反的运动则会激发胫节伸肌运动神经元和另一组发放冲动的局部中间神经元。兴奋屈肌运动神经元的传入纤维发放的冲动会引发去极化电位，每个冲动之后都有大约1.5毫秒的恒定中枢潜伏期。去极化电位的幅度取决于运动神经元的膜电位。这一证据表明这种连接是直接的，且这些电位是兴奋性突触后电位（EPSP）。对某些发放冲动的局部中间神经元和某些屈肌运动神经元进行同步记录表明，它们共同接收许多突触电位，并由受体腱膜的运动以平行方式驱动。一些传入纤维的冲动在这两种神经元中都能引发具有相同一致性和潜伏期的兴奋性突触后电位。因此，一条传入纤维可以直接与一个运动神经元和一个发放冲动的局部中间神经元形成突触。每条传入纤维会与多个运动神经元以及可能与多个中间神经元形成突触。反过来，每个运动神经元和每个中间神经元都接收来自多条传入纤维的输入。
