Chabaud P, Ravel N, Wilson D A, Mouly A M, Vigouroux M, Farget V, Gervais R
Institut des Sciences Cognitives, CNRS-UPR 9075, 67 Boulevard Pinel, F-69675 Bron, France.
Chem Senses. 2000 Oct;25(5):561-73. doi: 10.1093/chemse/25.5.561.
This study investigated how changes in nutritional motivation modulate odour-related oscillatory activities at several levels of the olfactory pathway in non-trained rats. Local field potential recordings were obtained in freely moving animals in the olfactory bulb (OB), anterior and posterior parts of the piriform cortex (APC and PPC respectively) and lateral entorhinal cortex (EC). Dynamic signal analysis detected changes in power during odour presentation for several frequency bands The results showed that in most cases odour presentation was associated with changes in a wide 15-90 Hz frequency band of activity in each olfactory structure. However, nutritional state modulated initial responses to food odour (FO) in the OB and EC selectively in the 15-30 Hz frequency band. Changes in nutritional state also modulated responses to repeated FO stimuli. Habituation was expressed differentially across structures with a clear dissociation between the two parts of the piriform cortex. Finally, systemic injections of scopolamine (0.125 mg/kg) selectively blocked expression of the nutritional modulation in the OB found in the beta band. These results suggest that internal state can differentially modulate odour processing among different olfactory areas and point to a cholinergic-sensitive beta band oscillation during presentation of a behaviourally meaningful odorant.
本研究调查了营养动机的变化如何调节未受过训练的大鼠嗅觉通路多个水平上与气味相关的振荡活动。在自由活动的动物的嗅球（OB）、梨状皮质的前部和后部（分别为APC和PPC）以及外侧内嗅皮质（EC）中获取局部场电位记录。动态信号分析检测了气味呈现期间几个频段的功率变化。结果表明，在大多数情况下，气味呈现与每个嗅觉结构中15 - 90 Hz宽频段活动的变化相关。然而，营养状态选择性地在15 - 30 Hz频段调节OB和EC中对食物气味（FO）的初始反应。营养状态的变化也调节了对重复FO刺激的反应。不同结构之间的习惯化表现不同，梨状皮质的两个部分之间有明显的分离。最后，全身注射东莨菪碱（0.125 mg/kg）选择性地阻断了在β频段中发现的OB中营养调节的表达。这些结果表明，内部状态可以不同地调节不同嗅觉区域的气味处理，并指出在行为上有意义的气味剂呈现期间存在胆碱能敏感的β频段振荡。
