Figure 5.

Conceptual model of dynamics switching. Place cells A–D are sequentially connected by asymmetric synaptic connections. (A) Place cell firing in slow-wave-sleep and quiet waking with low acetylcholine. In this mode, strong synaptic transmission enables neural activity to propagate fast and activate all place cells sequentially within a few hundred milliseconds. (B) Place cell firing in active waking with high acetylcholine. In this mode, synaptic transmission is suppressed. However, a few spikes in each neuron activate the CAN current and drive persistent firing. Persistent firing will eventually cause enough temporal summation of EPSP in the cell downstream in the sequence. Sequential firing will occur at a much slower time scale compared to (A) because each neuron needs to activate the CAN current and drive persistent firing. Thick and thin arrows show strong and weak synaptic transmissions, respectively. Lightning signs in (B) show cholinergic receptor activation.