Takamura, Y., Tamura, R., Zhou, T.L., Kobayashi, T., Tran, A.H., Eifuku, S., Ono, T. Spatial firing properties of lateral septal neurons. Hippocampus 16: 635-644 2006. mǗLn


The present study describes the spatial firing properties of neurons in the lateral septum (LS). LS neuronal activity was recorded in rats as they performed a spatial navigation task in an open field. In this task, the rat acquired an intracranial self-stimulation (ICSS) reward when it entered a certain place, the location that varied randomly from trial to trial. Of 193 neurons recorded in the LS, 81 showed place-related activity. The majority of the tested neurons changed place-related activity when spatial relations between environmental cues were altered by rotating intra-field (proximal) cues. The comparison of place activities between LS place-related neurons recorded in the present study and hippocampal place cells recorded in our previous study, using identical behavioral and recording procedures, revealed that spatial parameters (spatial information content, coherence, and cluster size) were smaller in the LS than in the hippocampus. Of 193 LS neurons, 86 were influenced by ICSS rewards; 31 of these 86 were also place-related. These results, together with previous anatomical and behavioral observations, suggested that the spatial information sent from the hippocampus to the LS is modulated and interacted with signals related to reward in the LS.


Key words: spatial information; intracranial self-stimulation; lateral septal nuclei; hippocampus; place cells.