ИСТИНА

Neuronal encoding of experience-dependent perception has long been in the focus of neuroscience of consciousness. The specific neuronal mechanisms for such perception of object and space remains an open question. We test the hypothesis that neurons in hippocampus and retrosplenial cortex (RSC) encode spatial and object information respectively, and that aging impairs two forms of memory differently. We developed an approach combining optical recording of neuronal activity and assessment of animal behavior during exploration episodes for novelty of object type (NOR) and novel place of familiar object (OPR) in young and old mice. We trained young (2-3 mo.) and old (18-21 mo.) mice in NOR and OPR. Young and old mice demonstrate short-term (120 min after) but not long-term memory (24 h after) in both tasks. We recorded object-type and object-place awareness-related neural activity in RSC and CA1 of young mice by calcium fiber-optic photometry. We found an increase in the number of calcium events in RSC when animals explored a new position of familiar object, and a decrease during novel object exploration. Using multiphoton microscopy and minimicroscopy we registered calcium activity of RSC and CA1 neurons during NOR and OPR tasks. Different classes of neurons were identified – demonstrating an increase and decrease of activity during exploration of place and objects, as well as cells that were active during specific behavioral acts. Thus, we showed that both object-type and object-place experience-dependent memory was expressed in the activity of RSC and CA1 neurons. Supported by RSF 20-15-00283, RFBR 17-00-00215, 19-315-80020, 18-32-20212