Figure 4.

Temporal development of recording quality. Left column: time (in days) after implantation. Symbols: Dot: technically defect electrode or amplification channel. Blank: technically intact, but no spike recorded. Rectangles of different height: 1, 2, or 3 spike trains recorded, respectively, by each one electrode. On electrode no 2 on days 263 and 275 we could properly discriminate four different spike trains. This is rendered by higher rectangles but the category “four spike separable trains” was not considered henceforth.