Figure 2.

Synaptic potentiation in wake and down-selection in sleep. (A) During wake, plasticity is dominated by potentiation. Synapses are potentiated when a neuron receives persistent feedforward activation and longer timescale feedback activations on the same dendritic domain, the neuron itself exhibits strong activation, and global neuromodulators are present. The orange box indicates the dendritic domain which meets these requirements for LTP. Conversely, the gray box indicates a dendritic domain which is missing feedback activity, so either no change happens or LTD is induced. (B) In sleep, global neuromodulators are largely absent. The synapses in a dendritic domain are protected when the neuron is strongly activated by matching feedforward and feedback activations (gray box, left dendritic domain). Conversely, LTD occurs when a neuron fires but its feedforward and feedback are mismatched within a dendritic domain (purple box, right dendritic domain).