Figure 10. Effect of GABA on the network state transitions.
(A) Both phasic and tonic GABA conductances were fixed for entire simulation. Note the state transitions similar to the baseline model (Figure 2). (B) Tonic GABA conductance (conductance of the miniature IPSPs) was varied based on the measured GABA levels in microdialysis experiments (mIPSPs were modified as 115%, 130% and 75% of awake stage for N2, N3 and REM stages, respectively), while phasic GABA conductance was remained fixed. (C) Assuming co-release of ACh with GABA, tonic GABA conductance was proportionally varied with ACh concentration (mIPSP for GABA conductance was scaled as 85%, 70% and 125% of awake stage for N2, N3 and REM stages respectively). Transition between sleep stages was observed in all these conditions, but spindles were less synchronous in C; in A and B alpha-bursts were less common.