Olfactory associative conditioning in infant rats with brain stimulation as reward: II. Norepinephrine mediates a specific component of the bulb response to reward.

Publisher Website
Google Scholar
Abstract
One of the circuits modified by early olfactory learning is in the olfactory bulb. Specifically, response patterns of mitral-tufted cells are modified by associative conditioning during the early postnatal period. In addition, previous work has demonstrated that mitral-tufted cell single units respond to both olfactory conditioned stimuli and rewarding stimulation of the medial forebrain bundle-lateral hypothalamus (MFB-LH). The present study suggests that norepinephrine beta-receptor activation is required for early olfactory learning using MFB-LH stimulation as reward. Propranolol injected before odor-MFB-LH pairings blocks the acquisition of conditioned behavioral responses and their neural correlates to the conditioned odor. Furthermore, propranolol blocks a specific class of the mitral-tufted cell responses to MFB-LH reward stimulation. The relationship of this response to reward and early learning is discussed.