Schriever V A, Frenzel C, Wernecke S, Croy I, Valder C, Hummel T
Smell & Taste Clinic, Department of Otorhinolaryngology, University of Dresden Medical School, Dresden, Germany; Department of Neuropediatrics, University of Dresden Medical School, Dresden, Germany.
Smell & Taste Clinic, Department of Otorhinolaryngology, University of Dresden Medical School, Dresden, Germany.
Neuroscience. 2015 Jun 4;295:72-9. doi: 10.1016/j.neuroscience.2015.03.029. Epub 2015 Mar 23.
Compared to other senses, temporal perception of odors seems fairly slow. In addition it has been shown in previous studies that even not consciously perceived odors could influence our behavior. Aim of the current study therefore was to study the interstimulus interval (ISI) length, which is necessary between two repetitive stimuli to be able to perceive them separately. The additional aim focused on observing central odor processing of not perceived odorous stimuli.
The study was divided into three parts. In each part healthy, normosmic volunteers were included. In part I and II stimulus pairs (CO2, H2S, orange and phenyl ethyl alcohol (PEA)) were presented to the subjects via a computer-controlled olfactometer with short ISI of 0.6-9s. The decision whether one or two stimuli were perceived was recorded. In addition the influence of odor valence, trigeminallity and concentrations was observed. In part III olfactory event-related potentials (OERPs) to perceived and not-perceived odors were recorded.
The two stimuli of a stimulus pair were perceived separately more often with increasing ISI length. This increase was significant until an ISI between the stimuli of 4s. Odor intensity, pleasantness, trigeminallity and sex had no major influence on this. In addition we were able to observe that OERPs are less often detected in response to not perceived olfactory stimuli. However, the presence of OERP in response to not perceived stimuli in more than half of the cases indicated that even not perceived stimuli are centrally processed.
与其他感官相比，对气味的时间感知似乎相当缓慢。此外，先前的研究表明，即使是未被有意识感知到的气味也会影响我们的行为。因此，本研究的目的是研究两个重复刺激之间能够被分别感知所需的刺激间隔（ISI）长度。另一个目的是观察未被感知到的气味刺激的中枢气味处理过程。
本研究分为三个部分。每个部分都纳入了健康的、嗅觉正常的志愿者。在第一部分和第二部分中，通过计算机控制的嗅觉计向受试者呈现刺激对（二氧化碳、硫化氢、橙子和苯乙醇（PEA）），刺激间隔短，为0.6 - 9秒。记录受试者感知到一个还是两个刺激的判断结果。此外，还观察了气味效价、三叉神经刺激性和浓度的影响。在第三部分中，记录了对已感知和未感知气味的嗅觉事件相关电位（OERP）。
随着ISI长度增加，刺激对中的两个刺激更常被分别感知。在刺激间ISI达到4秒之前，这种增加是显著的。气味强度、愉悦度、三叉神经刺激性和性别对此没有重大影响。此外，我们观察到对未被感知的嗅觉刺激产生的OERP较少被检测到。然而，在超过一半的情况下，对未被感知刺激有OERP反应，这表明即使是未被感知的刺激也会在中枢进行处理。
