Frequency-dependent regulation of afferent transmission in the feeding circuitry of Aplysia.
Frequency-dependent regulation of afferent transmission in the feeding circuitry of Aplysia.
复制标题
海兔喂养电路中传入传输的频率依赖性调节。
DOI：
10.1152/jn.00786.2003
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发表时间：
2003
期刊：
影响因子：
--
通讯作者：
Cropper,ElizabethC
中科院分区：
文献类型：
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作者：
Evans,ColinG;Jing,Jian;Proekt,Alex;Rosen,StevenC;Cropper,ElizabethC
During rhythmic behaviors, sensori-motor transmission is often regulated so that there are phasic changes in afferent input to follower neurons. We study this type of regulation in the feeding circuit ofAplysia. We characterize effects of the B4/5 interneurons on transmission from the mechanoafferent B21 to the radula closer motor neuron B8. In quiescent preparations, B4/5-induced postsynaptic potentials (PSPs) can block spike propagation in the lateral process of B21 and inhibit afferent transmission. B4/5 are, however, active during the retraction phase of motor programs, i.e., when mechanoafferent transmission to B8 presumably occurs. To determine whether mechanoafferent transmission is necessarily inhibited when B4/5 are active, we characterize the B4/5 firing frequency during retraction and show that, for the most part, it is low (below 15 Hz). There is, therefore, a low probability that spike propagation will be inhibited. The relative ineffectiveness of low frequency activity is not simply a consequence of insufficient PSP magnitude, because a single PSP can block spike propagation. Instead, it is related to the fact that PSPs have a short duration. When B4/5 fire at a low frequency, there is therefore a low probability that afferent transmission in the lateral process of B21 can be inhibited. In conclusion, we demonstrate that afferent transmission will not always be affected when a neuron that exerts inhibitory effects is active. Although a cell may be ineffective when it fires at a low frequency, ineffectiveness is not necessarily a consequence of spike frequency per se. Instead it may be due to spike timing.
