Fig. 3.

Comparative measurements on HEK293 cells expressing ChR-2 with the DAIMM and the patch-clamp method. (A) A typical zero-current clamp measurement using the patch-clamp technique on a ChR2-expressing cell is shown. Note that during blue-light illumination (indicated by the arrow), a steady-state depolarization of the cell with an initial transient potential component occurs.⁴⁶ (B) Measurements by means of the DAIMM method using comparable experimental conditions as in (A). The three voltage curves represent typical results in absence or presence of blue-light illumination experiments under zero-current clamp conditions by using HEK293 cells expressing ChR2, control HEK293 cells, and in the absence of any cells (insets).