Laminar-Specific fMRI Changes in Rat Olfactory Bulb Following Evoked Odor Stimulation

Alexander John Poplawsky¹, Seong-Gi Kim¹

The olfactory bulb is an excellent model to study laminar-specific activation because each layer has different neurophysiological roles in odorant encoding. Here, we measured signal changes across different layers of the olfactory bulb in response to an evoked odor stimulus using CBV and BOLD fMRI. We found that CBV had increased sensitivity and spatial-specificity compared to BOLD. In addition, CBV images had large activation foci surrounded by diffuse, global activation and laminar profiles that were similar to 2-deoxy-D-glucose autoradiographic studies. We conclude that CBV fMRI measures changes at sites specific to neural activity at all laminar depths.