The team led by the research director Kaoru Inokuchi, Professor at University of Toyama, reports neural circuit mechanism underlying behavioral tagging, in which petty daily experiences are sometimes consolidated into long-lasting memories when surprising events happen within a short time interval.
Behavioral tagging is the transformation of a short-term memory, induced by a weak experience, into a long-term memory (LTM) due to the temporal association with a novel experience. The mechanism by which neuronal ensembles, each carrying a memory engram of one of the experiences, interact to achieve behavioral tagging is unknown. Here, they show that retrieval of a LTM formed by behavioral tagging of a weak experience depends on the degree of overlap with the neuronal ensemble corresponding to a novel experience. The numbers of neurons activated by weak training in a novel object recognition (NOR) task and by a novel context exploration (NCE) task, denoted as overlapping neurons, increases in the hippocampal CA1 when behavioral tagging is successfully achieved. Optical silencing of an NCE-related ensemble suppresses NOR–LTM retrieval. Thus, a population of cells recruited by NOR is tagged and then preferentially incorporated into the memory trace for NCE to achieve behavioral tagging.
Research Area “BIODYNAMICS”project
Research Theme “Memory integration process based on cell assembly and neural circuit model”
Research Director: Kaoru Inokuchi (Professor, University of Toyama)
Masanori Nomoto, Noriaki Ohkawa, Hirofumi Nishizono, Jun Yokose, Akinobu Suzuki, Mina Matsuo, Shuhei Tsujimura, Yukari Takahashi, Masashi Nagase, Ayako M. Watabe, Fusao Kato, and Kaoru Inokuchi. “Cellular tagging as a neural network mechanism for behavioural tagging”. Nature Communications, 7:12319, Published online 01 August 2016, doi: 10.1038/ncomms12319.
Kaoru Inokuchi, Ph.D.
Professor, Department of Biochemistry, Faculty of Medicine, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama
Life Innovation Group, Department of Innovation Research, JST