Slide 14

Figure 14. Activity-dependent, positive feedback electrical field enhances slow oscillation. Negative feedback field decreases rhythmic structure of the slow oscillation.

• (A) Feedback loop is provided by real-time field simulator that provides an EF based on the ongoing multiunit activity. Top: Sample multi-unit trace. Bottom: Simulated EFs.
• (B) Representative positive feedback sample experiment. Slow oscillation is more regular in presence of the feedback loop (bottom) than in absence (control, top).
• (C) Correlogram of multiunit activity shows both an enhanced central peak (CP) and a more pronounced side-band peak (SB) in presence of the positive feedback (red) in comparison to control condition without feedback (black).
• (D) Group data correlograms (n = 7). Activity levels (left) and slow oscillation structure (right) were enhanced in presence of positive feedback field with median relative increase in CP amplitude: 120% (p = 0.016) and SB/CP ratio: 150% (p = 0.031).
• (E) Negative feedback experiments. Left: Endogenous EF in vitro (black) and EF in presence of negative feedback field (red). Right: Positive peak field strength at onset of Up state was reduced to 47% of control (p = 0.0078, n = 8).
• (F) Coefficient of variation of both Up and Down state duration decreased in presence of positive feedback EF (red, Up: 86%, p = 0.016; Down: 83%, p = 0.016) but increased in presence of negative feedback EF (blue, 111% of control for both, n = 8, p = 0.0039 and p = 0.0078, respectively).