Figure 2.

Surgical procedure for the animal study. (A) Two craniotomies were performed. (B), (C) Two probes from each of the five groups were implanted simultaneously via a custom designed surgical holder. (D) Dental cement was used to fix the surgical holder, and the wound was sutured. The animal was placed on a heating pad until recovery from anesthesia. (E) Location and dimension of the two craniotomies and the ten probes (table 1 for number reference) with different dimensions. Black circle display the location of the four skull screws. A = 4 mm; b = 4 mm; c = 6 mm; d = 3 mm.