Gottfried Jay A
Cognitive Neurology & Alzheimer's Disease Center, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA.
Ann N Y Acad Sci. 2007 Dec;1121:102-20. doi: 10.1196/annals.1401.018. Epub 2007 Sep 10.
It is widely presumed that odor quality is a direct outcome of odorant molecular structure, but increasing evidence suggests that learning, experience, and context play important roles in human olfactory perception. Such data suggest that a given set of olfactory receptors activated by an odorant does not map directly onto a given odor percept. Rather, odor perception may rely on more synthetic, or integrative, mechanisms subserved by higher-order brain regions. Results presented here explore the specific role of human orbitofrontal cortex (OFC) in the formation and modulation of odor quality coding. Combining olfactory psychophysical techniques and functional imaging approaches, we have found that sensory-specific information about an odorant is not static or fixed within human olfactory OFC, but is highly malleable and can be rapidly updated by perceptual experience. Critically, the magnitude of OFC activation predicts subsequent behavioral improvement in olfactory perception. Our findings highlight the pivotal role of OFC in linking olfactory sensation, perception, and experience. It is worth considering that many of the current proposed functions attributed to the (distinctively mammalian) OFC are an extension of mechanisms that originally evolved to mediate response flexibility between chemosensory signals and appropriate behavioral actions.
人们普遍认为气味品质是气味分子结构的直接结果，但越来越多的证据表明，学习、经验和情境在人类嗅觉感知中起着重要作用。这些数据表明，由一种气味激活的一组特定嗅觉受体并不直接对应于一种特定的气味感知。相反，气味感知可能依赖于由高阶脑区支持的更综合或整合的机制。此处呈现的结果探讨了人类眶额皮质（OFC）在气味品质编码的形成和调节中的特定作用。结合嗅觉心理物理学技术和功能成像方法，我们发现关于一种气味的感觉特异性信息在人类嗅觉OFC内并非静态或固定不变的，而是具有高度可塑性，并且可以通过感知经验迅速更新。至关重要的是，OFC激活的程度可预测随后嗅觉感知方面的行为改善。我们的发现凸显了OFC在连接嗅觉感觉、感知和经验方面的关键作用。值得考虑的是，当前许多归因于（独特的哺乳动物）OFC的拟议功能是最初进化来介导化学感觉信号与适当行为动作之间反应灵活性的机制的延伸。
