结合磁共振成像和脑机接口的新型在体生物电子鼻的研究

摘要

By using mammal's own olfactory system,sensitivity and specificity of the in vivo bioelectronic nose is substantially enhanced.However,the specific region in the olfactory bulb where to implant the electrode has been based on the researcher's experiences,which often results in unsatisfied success rate.This study takes advantage of the paramagnetism and calcium ion similarity of the manganese ion.A small dose of manganese ion was delivered into the right naris of l0 rats,an odor was delivered to the nose of the rat,and a series of magnetic resonance images (MRI) were taken.With the MRI data,a region in the olfactory bulb activated by the specific odor was identified.Micro-wire electrode was implanted into the region and olfactory signals were recorded.When the rat was stimulated by the specific odor,the β wave of the LFP was found to increase and the spike signals also had responses.Linearity was observed between the difference of the spike-firing rate caused by the odor stimulation and the concentration of the odor.The limits of detection to isoamyl acetate and n-butyric acid were determined to be 0.033μM and 0.0072μM,respectively.As the first bioelectronic nose assisted by manganese-enhanced MRI,it has a promising future in explosives searching or food safety.%在体生物电子鼻利用了哺乳动物的嗅觉系统,因此具有很高的灵敏度和特异性,但在嗅球中植入电极的过程中其位置主要根据经验确定,因此成功率并不理想.利用锰离子的钙离子相似性和强顺磁性,在10只大鼠单侧鼻腔中滴入锰离子并给予气味刺激,进行磁共振扫描并标记出大鼠嗅球中的对特定气味的响应区域.在该区域中植入微丝阵列电极,记录电生理信号并就行神经信号解码,实验结果表明,受到该特异性气体刺激后,嗅球神经元的电生理信号中LFP信号β波能量增强,spike信号对该气体刺激也会有响应,并且有些通道的spike发放频率变化与刺激气体的浓度有较好的线性关系.此方法对乙酸异戊酯和正丁酸的检测下限分别为0.033和0.007 2μM.第一次利用锰离子增强磁共振辅助定位的生物电子鼻,未来在爆炸物搜索、食品安全等方面都有广阔的前景.