ABSTRACT
Objective To study whether mechanical noise acting on the sacculus could enhance the SNR of the 8th nerve’s response.Methods Driving PZT by adding white noise of various level to periodic signals(f=100 Hz),the directly mechanical stimuli was give to the five sacculus submerged in a solution containing perilymph-like, and the afferent activity the 8th nerve was recorded.Results The SNR of the nerve signal was improved by addition nanometer-level noise to the periodic stimuli in all responsive animal(4.1 dB, on average).It was found that 2.3 nm of mechanical noise enhanced the response of the saccular nerve.Conclusion The addition of a few nanometers of noise to a periodic stimuli leads to a substantial improvement in the SNR of the nerve’s response.
ABSTRACT
Objective To explore the differences of cultivation and differentiation between cortical neural stem cells(C-NSCs) and mesencephalic neural stem cells(M-NSCs). Methods We dissociated embryonic cortex and ventral mesencephalon respectively,and single cell suspensions were achieved by trypsin digestion and mechanical dissociation in sterile condition.These cells were planted into DMEM/F12 culture medium with B27,bFCF,and then were passaged by mechanical methods and induced to differentiation in DMEM/F12 medium with 10%FBS(without growth factors).For examining the features of C-NSCs and M-NSCs,reverse phasecontrast microscopy,immunocytochemical techniques were applied to detect nestin,NSE,GFAP antigens and the specific antigen(TH) of neurons differentiated from the two kinds of NSCs.We observed and compared the difference of the two kinds of NSCs. Results The NSCs existed both in cortex and ventral mesencephalon of embryonic mice,which expressed nestin and possessed the ability of self-renewing and multipotent, but the density of NSCs in cortex was higher than that in ventral mesencephalon.There were some TH positive cells differentiated from M-NSCs but none came from C-NSCs.Conclusion The proliferative activity of C-NSCs is higher than that of M-NSCs,but more number M-NSCs differentiated into dopaminergic neurons in serum medium.