Synaptic tagging

Synaptic tagging, or the synaptic tagging hypothesis, was first proposed in 1997 by Julietta U. Frey (her publishing name was Uwe Frey or J. U. Frey before the year 2000 (https://scholar.google.com/citations?user=sghJBzMAAAAJ&hl=en&citsig=AD-1fHaN4xLB44tNjIiILbQWZcfn)) and Richard G. Morris; it seeks to explain how neural signaling at a particular synapse creates a target for subsequent plasticity-related product (PRP) trafficking essential for sustained LTP and LTD. Although the molecular identity of the tags remains unknown, it has been established that they form as a result of high or low frequency stimulation, interact with incoming PRPs, and have a limited lifespan.

Further investigations have suggested that plasticity-related products include mRNA and proteins from both the soma and dendritic shaft that must be captured by molecules within the dendritic spine to achieve persistent LTP and LTD. This idea was articulated in the synaptic tag-and-capture hypothesis. Overall, synaptic tagging elaborates on the molecular underpinnings of how L-LTP is generated and leads to memory formation.