Synaptic mechanisms for motor variability in a feedforward network
Guo Zhang, Ke Yu, Tao Wang, Tingting Chen, Wang-Ding Yuan, Fan Yang, Ziwei Le, Shi‐Qi Guo, Ying-Yu Xue, Songan Chen, Zhe Yang, Feng Liu, Elizabeth C. Cropper, Klaudiusz R. Weiss, Jian Jing
Abstract
feeding system. A command-like neuron (CBI-10) triggers rhythmic motor programs more variable than programs triggered by CBI-2. CBI-10 weakly excites a pivotal pattern-generating interneuron (B34) strongly activated by CBI-2. The activation properties of B34 substantially account for the degree of program variability. CBI-10- and CBI-2-induced EPSPs in B34 vary in amplitude across trials, suggesting that there is synaptic noise. Computational studies show that synaptic noise is required for program variability. Further, at network state transition points when synaptic conductance is low, maximum program variability is promoted by moderate noise levels. Thus, synaptic strength and noise act together in a nonlinear manner to determine the degree of variability within a feedforward network.