Fredman S M, Jahan-Parwar B
Brain Res Bull. 1979 May-Jun;4(3):393-406. doi: 10.1016/s0361-9230(79)80017-9.
Synaptic connections were found between two groups of neurons in the CNS of Aplysia, the cerebral ganglion A and B cluster neurons which are involved in the control of pedal and parapodial movements and neurons in the pleural ganglion which has been shown to modulate locomotion. The A and B neurons made synaptic connections in both the cerebral and pleural ganglia. Pleural neurons had synaptic connections among themselves and with A and B neurons. The A neurons made excitatory monosynaptic connections with the B neurons and a minimum of 6 pleural neurons including the left giant cell (LGC). All of the A neuron synapses found were excitatory. The B neurons received excitatory synaptic input from two other groups of neurons in the cerebral ganglion and both excitatory and inhibitory input from pleural neurons. The latter were identified on the basis of their synaptic connections with the LGC and A neurons. The B neurons and LGC had several common synaptic inputs. The A neurons received monosynaptic input from only 2 pleural neurons. Complex synaptic circuits between A and B neurons and pleural neurons were found. These included recurrent inhibition of B neurons by A neurons via a pleural interneuron, feedforward summation of A neuron synaptic input to the LGC, and reciprocal excitatory synaptic connections between B and the pleural neurons. The activity of the B neurons was modulated by direct inhibitory and excitatory synaptic connections from pleural neurons. The A neurons were modulated primarily by a polysynaptic pathway through the B neurons. The modulation of cerebral A and B neurons by pleural neurons is consistent with behavioral results obtained studying locomotion.
在海兔的中枢神经系统中，发现两组神经元之间存在突触连接，即参与控制足和副足运动的脑神经节A簇和B簇神经元，以及已被证明可调节运动的胸膜神经节中的神经元。A神经元和B神经元在脑和胸膜神经节中均形成了突触连接。胸膜神经元之间以及与A神经元和B神经元之间都有突触连接。A神经元与B神经元以及至少6个胸膜神经元（包括左巨细胞，LGC）形成兴奋性单突触连接。所有发现的A神经元突触都是兴奋性的。B神经元从脑神经节中的另外两组神经元接收兴奋性突触输入，并从胸膜神经元接收兴奋性和抑制性输入。后者是根据它们与LGC和A神经元的突触连接来确定的。B神经元和LGC有几个共同的突触输入。A神经元仅从2个胸膜神经元接收单突触输入。发现了A神经元和B神经元以及胸膜神经元之间的复杂突触回路。这些包括A神经元通过一个胸膜中间神经元对B神经元的反馈抑制、A神经元对LGC的突触输入的前馈总和，以及B神经元和胸膜神经元之间的相互兴奋性突触连接。B神经元的活动受到胸膜神经元直接的抑制性和兴奋性突触连接的调节。A神经元主要通过一条经过B神经元的多突触途径进行调节。胸膜神经元对脑A神经元和B神经元的调节与研究运动所获得的行为结果一致。
