Recent brain connectome studies have evidenced distinct and overlapping brain regions involved in processing olfactory perception. However, neural correlates of hypo- or anosmia in olfactory disorder patients are poorly known. Furthermore, the bottom-up and top-down processing of olfactory perception have not been well-documented, resulting in difficulty in locating the disease foci of olfactory disorder patients. The primary aim of this study is to characterize the bottom-up process of the neural dynamics across peripheral and central brain regions in anesthetized mice. We particularly focused on the neural oscillations of local field potential (LFP) in olfactory epithelium (OE), olfactory blub (OB), prefrontal cortex (PFC), and hippocampus (HC) during an olfactory oddball paradigm in urethane anesthetized mice. Odorant presentations evoked neural oscillations across slow and fast frequency bands including delta (1–4 Hz), theta (6–10 Hz), beta (15–30 Hz), low gamma (30–50 Hz), and high gamma (70–100 Hz) in both peripheral and central nervous systems, and the increases were more prominent in the infrequently presented odorant. During 5 s odorant exposures, the oscillatory responses in power were persistent in OE, OB, and PFC, whereas neural oscillations of HC increased only for short time at stimulus onset. These oscillatory responses in power were insignificant in both peripheral and central regions of the ZnSO 4 -treated anosmia model. These results suggest that olfactory stimulation induce LFP oscillations both in the peripheral and central nervous systems and suggest the possibility of linkage of LFP oscillations in the brain to the oscillations in the peripheral olfactory system.

A key question within systems neuroscience is to understand how the brain encodes spatially and temporally distributed local features and binds these together into one perceptual representation. Previous works in animal and human have shown that changes in neural synchrony occur during the perceptual processing and these changes are distinguished by the emergence of gamma-band oscillations (GBO, 30–80 Hz, centered at 40 Hz). Here, we used the mouse electroencephalogram to investigate how different cortical areas play roles in perceptual processing by assessing their GBO patterns during the visual presentation of coherently/incoherently moving random-dot kinematogram and static dots display. Our results revealed that GBO in the visual cortex were strongly modulated by the moving dots regardless of the existence of a global dot coherence, whereas GBO in frontal cortex were modulated by coherence of the motion. Moreover, concurrent GBO across the multiple cortical area occur more frequently for coherently moving dots. Taken together, these findings of GBO in the mouse frontal and visual cortex are related to the perceptual binding of local features into a globally-coherent representation, suggesting the dynamic interplay across the local/distributed networks of GBO in the global processing of optic flow.