IL-HFS applied immediately after fear retrieval/short extinction training reduces fear during extinction.

<p>(<b>A</b>) Schematic diagram showing electrode placement in IL for the fear conditioning experiments. Diagram adapted from Paxinos and Watson 1998. (<b>B</b>) Timeline of behavioral testing and stimulation. (<b>C</b>) Percent freezing (mean ± SEM) to CS during conditioning, fear retrieval, and extinction in rats receiving either sham or HFS after fear retrieval. HFS rats showed reduced fear during extinction relative to Shams (**<i>P</i><.01). (<b>D</b>) Percent freezing to CS during reconditioning and extinction in rats receiving either sham or HFS after fear retrieval. Reconditioning and re-extinction were not affected by prior IL stimulation. Data are Means ±SEM.