Supporting Information for PNAS paper:

Clusters of interacting receptors can stabilize
synaptic efficacies

Files in this Data Supplement:

Fig. 7. Parameter dependence of cluster model as a function of the repulsion constant L₁ and the slope of the stochastic insertion function b. The metastable region is indicated by green dots, the decay region is indicated by black dots, and the expansion region is indicated by red dots. Each dot represents the result of a single simulation.

Fig. 8. Cluster lifetimes and receptor dwell times as a function of b. The black error bars show the mean and standard deviation of the cluster’s lifetime. These were estimated from 10 runs per condition. The red and blue lines show the dwell times of receptors with two and three neighbors, respectively. In these simulations, L₁ = 1.5, m_off = 1, m_on = 0.01, and the initial size was 8 ´ 8 receptors. Lifetimes are defined as the time at which the cluster size goes below 1/e of the initial size.

Movie 1. Metastability of a cluster of receptors. Initial cluster size is 7 × 7 receptors. (Left) Images of the cluster. Gray squares indicate occupied grid location; black indicates unoccupied location. (Right) Blue line indicates instantaneous number of receptors as a function of time.

Movie 2. Stability in a triangular cluster. (Left) Blue circles indicate location of site occupied with receptor. (Right) Blue line indicates number of receptors as a function of time.

Movie 3. LTP induction. (Left) White squares indicate second population of receptors. (Right) Red line indicates number of inserted receptors of the second type. Time in which the second type of receptors are available for insertion is indicated by gray background.

Movie 4. LTP induced by an alternative mechanism in which L₁ is transiently reduced for all receptors. (Right) As in Movie 3. (Left) Gray background indicates time during which L₁ is reduced.

Movie 5. LTD induction. (Left) As in Movie 3. (Right) Endocytosis rate is increased, as indicated by gray background.

Movie 6. LTD induction by alternative mechanism in which L₁ is transiently increased. (Left) As in Movie 3. (Right) Gray background indicates time in which L₁ is increased.

Movie 7. Cluster dynamics in an off-rate model. Conventions are as in Movie 1.