Target-specific modulation of the descending prefrontal cortex inputs to the dorsal raphe nucleus by cannabinoids

Serotonin (5-HT) neurons located in the raphe nuclei modulate a wide range of behaviors by means of an expansive innervation pattern. In turn, the raphe receives a vast array of synaptic inputs, and a remaining challenge lies in understanding how these individual inputs are organized, processed, and modulated in this nucleus to contribute ultimately to the core coding features of 5-HT neurons. The details of the long-range, top-down control exerted by the medial prefrontal cortex (mPFC) in the dorsal raphe nucleus (DRN) are of particular interest, in part, because of its purported role in stress processing and mood regulation. Here, we found that the mPFC provides a direct monosynaptic, glutamatergic drive to both DRN 5-HT and GABA neurons and that this architecture was conducive to a robust feed-forward inhibition. Remarkably, activation of cannabinoid (CB) receptors differentially modulated the mPFC inputs onto these cell types in the DRN, in effect regulating the synaptic excitatory/inhibitory balance governing the excitability of 5-HT neurons. Thus, the CB system dynamically reconfigures the processing features of the DRN, a mood-related circuit believed to provide a concerted and distributed regulation of the excitability of large ensembles of brain networks.

Numerical Simulation of Hydro-Forming Process of Shaped Tube

in the forming process of section tube using hydro forming, distributed regulation of the strain, loading rate and destabilization have a large influence to forming. The forming process is simulated by means of FEM in this paper. Simulation results shows that strain are maximal at the convexity and concave of die. And with pressure increasing, the phenomenon of destabilization would occur on some side of its convexity randomly, the forming process of section tub can be divided into two obvious stages. Besides, critical pressure of two stages is pointed out. The simulation results are compared with the experiment results, and the correctness of the simulation is verified.