SAN2020

The lateral habenula (LHb) is a key structure in neural circuits that encodes motivation. It receives inputs from the basal ganglia and limbic structures and projects to regions such as the ventral tegmental area and the rostromedial tegmental nucleus. Furthermore, the LHb is functionally related to the hippocampus, albeit not directly connected. Accordingly, there is some evidence showing that the LHb is necessary for spatial processing. The main goal of our study is to understand the involvement of the LHb in the processing of spatial information and ultimately to assess how it functionally interacts with the hippocampus for the coding and processing of spatial information. We present herein preliminary data obtained using a novel object location memory paradigm and optogenetics to modulate LHb neuronal activity in long-evans rats. Both channelrhodopsin expressing rats and control rats showed no long term memory when blue light was administered to LHb during training. Considering that in control experiments (no light stimulation) both groups learned equally well, we hypothesize that light itself might be exerting an effect per se, which seems possible according to the literature. It is worth mentioning that optogenetic modulation of LHb neurons does not affect locomotion or anxiety levels, and the same manipulation affects contextual fear conditioning memory. Future experiments will be discussed in order to continue the project.