Focal 2-DG uptake persists following olfactory bulb lesions

Exposure of rats to different odors produces spatially distinct patterns of 14C-2-deoxyglucose uptake (2-DG) in the glomerular layer of the main olfactory bulb. However, lesions of specific regions of the bulb that reliably contain 2-DG foci reportedly do not impair the ability of rats to perform olfactory-guided behaviors, suggesting that the lesioned olfactory bulb retains odor-responsiveness. Because the absence of focal 2-DG incorporation in lesioned olfactory bulbs has not been verified by 2-DG autoradiography, it cannot be concluded that focal responses in the olfactory bulb do not contribute to the encoding of olfactory information. To examine the effects of bulb lesions on 2-DG uptake in the olfactory bulb, we placed lesions in specific regions of the bulb that reliably contain 2-DG foci. We then exposed rats to odors 3 or 6 weeks later to determine if the lesions effectively eliminated focal 2-DG uptake in these bulbs. The results indicate that lesioned olfactory bulbs contain focal regions of 2-DG uptake in response to odor stimulation.