Erratum to: Neuroprotection and spatial memory enhancement of four herbal mixture extract in HT22 hippocampal cells and a mouse model of focal cerebral ischemia.

Unfortunately, the original version of this article [1] contained an error. The corrected Figure four (Fig. 1) can be found below. The Figure four (Fig. 1) has been corrected in the original article and is also included correctly below.

Fig. 1

Protective effect of PMC-12 on ROS generation in glutamate-treated HT22 cells. Cells were pretreated with 0.01, 0.1, 1, or 10 μg/ml of PMC-12 for 24 h, followed by exposure to 5 mM glutamate for 24 h. The oxidation sensitive fluorescence dye, carboxy-H 2 DCFDA (20 μM), was used in measurement of ROS levels. Production of ROS was analyzed using a fluorescence plate reader (a) and fluorescence microscope (b). In addition, apoptotic nuclei were observed after staining with Hoechst 33342 for detection of apoptosis morphologically (b). ### P < 0.001 vs. control; **P < 0.01 and ***P < 0.001 vs. glutamate-treated cells. All data are represented as the mean ± SEM of three independent experiments. Scale bars = 50 μm