目的 通过观察嗅觉中枢的激活 情况，探讨不同的嗅觉刺激模式是否会影 响嗅觉fMRI结果。方法 分别选择两种不 同的嗅觉刺激模式对同一受试者进行嗅觉 fMRI检查，选择双侧初级嗅觉皮层区为 ROI，观察其在两种模式下的激活情况以 及BOLD信号强度的变化，比较两者之间是 否有所差别。结果 16名正常志愿者两种 嗅觉刺激模式下的ROI区激活体素数无统 计学差异(定时模式为69．00±80.23，触 发模式为102.81±151.44，P值=0.42)， 且平均BOLD时间-信号强度变化曲线也无 统计学差异(P值=0.167)。结论 无论是定 时模式还是触发模式，在刺激持续时间内 均存在至少一次的有效的吸气相，嗅觉中 枢的激活反应也是没有差异的，因此不同 嗅觉刺激模式对嗅觉fMRI结果是没有影响 的。

Objective To study the effects of different odor stimulation paradigms on olfactory fMRI results by observing the activation of olfactory central system. Methods Two different olfactory stimulation paradigms olfactory fMRI were executed on the same subjects,and extracted bilateral primary olfactory cortex area as ROI, observing its activation responding and BOLD signal intensity changes, to see whether there are any differences between the two paradigms. Results The ROI area activation responding of both two odor stimulation paradigms of 16 normal volunteers showed no statistical differences (fixed paradigm were 69.00±80.23, trigger paradigm were 102.81±151.44, P values=0.42), and there was no statistical differences between the two average time of BOLD signal intensity curve (P values=0.167). Conclusion No matter what the paradigm is, there should be at least one effective inspiratory phase in the duration of odor stimulation,it should cause the same activation response in the olfactory center. Therefore, different paradigms of olfactory stimulation do not effect on the result of olfactory fMRI.