The aim of the present study was to investigate the electrophysiological characteristics of the different layers of the olfactory bulb (OB). We used an in vitro OB slice coupled onto a microelectrode array (MEA) for simultaneous detection of spontaneous activities of OB neurons at different sites. Different frequency oscillations dominated the different layers of the OB slice, and the gamma frequency oscillations mainly appeared in the glomerular layer. The waves consisted of negative, positive, and bidirectional spikes, and were distributed at the different layers of the OB slice. Thus, combination of the OB slice with MEA is a useful technique for identifying signal oscillations by multi-site synchronous measurement, and will allow further studies on olfactory information coding and processing function.
Mammalian olfactory systems have extraordinary ability to sense and identify various trace odorants.Taking advantages of cell culture and micro-fabrication technologies,olfactory cell-or tissue-based biosensor represent a promising platform for in vitro odorant detection.However,in vitro conditions lead to shortened cell/tissue survivals,and the working life of neuron chips is short.The purpose of this study is to develop an in vivo recording and analyzing method for long-term and repeatable detection of odor stimulation.In this study,we implanted penetrating micro-wire array electrode into the olfactory bulb of conscious rats to obtain odor-evoked electrophysiological activities.Then,we investigated the response of ensembles of mitral/tufted cells to stimulation with carvone at a number of concentrations in time and frequency domains.The stable,repeatable odorant responses from up to 16 neural regions could be obtained for at least 3 weeks.Further,we explored the concentration detection sensitivity limitation of developed method,and found the detection low limit of carvone was below10-10mol/L.The result demonstrates that the concentration range of in vivo odorant detection method is much wider than in vitro method.
Liujing ZhuangNing HuFeng TianQi DongLiang HuRong LiPing Wang
