State Based Model of Long-Term Potentiation and Synaptic Tagging and Capture
Figure 2
The effects of tetanisation on the state transitions.
(A,B) Each diagram represents the state diagram for the model, and the super-imposed arrows indicate the transition rates that are significant in the given scenario, at the given time. To indicate how STC is incorporated into the model, we show a tetanised synapse and an unstimulated synapse. (A) Weak HFS only affects the synapse to which it is applied, and transition into the e-LTP state occurs over a period of a few minutes. (B) Strong HFS initially has the same effect as a weak tetanus. However, protein synthesis and diffusion are triggered by this stimulus: at 20 minutes after stimulus onset, both synapses are affected by rapid transition rates from their e-LTP to states, and also from their e-LTD to
states. Thus if weak HFS or LFS were given to the unstimulated synapse in this scenario, then the STC process would occur. (In the latter case one has “cross-capture”.) (C) The time course of the transition rate
from the strong basal state to the e-LTP state following weak HFS at time
. (D) The time course of the transition rate
from the e-LTP state to the
state following strong HFS starting at time
.