Figure 2.

Coordinate system and recording chamber orientation. (A) Stereotactic coordinate system: the X axis extends from left to right, the Y axis from posterior to anterior, and the Z axis from ventral to dorsal. The axes intersect at the origin of the coordinate system. (B) Recording chamber with a positive elevation angle. The orientation of the central axis of the recording chamber is indicated by the yellow vector. Note that the axes represent a translated coordinate system. The Y and Z axes and the central axis of the recording chamber intersect at the location of the target node. (C) Recording chamber with a negative elevation angle. (D) Recording chamber with a positive tilt angle. (E) Recording chamber with a negative tilt angle.