Figure 4
VNS treatment reversed PTSD-like symptoms of anxiety and exaggerated startle. (a) VNS administration during extinction reduced anxiety. One week after the completion of extinction, PTSD model rats spent less time in the open arms of the maze than AFC alone rats (##P<0.01), indicating heightened anxiety. VNS during extinction reversed this effect in PTSD model rats and also decreased anxiety in AFC alone rats. VNS-treated rats spent more time in the open arms versus sham-treated rats in the PTSD model (**P<0.01) and in the control group that underwent AFC alone (*P<0.05). (b) VNS treatment increased entries into the open arms. Similar to time spent in the open arms, PTSD model rats showed a reduced number of entries into the open arms versus AFC alone rats (##P<0.01). Administration of VNS during extinction reversed this effect and increased entries into the open arms in PTSD model rats (***P<0.001) and in AFC alone rats (*P<0.05). (c) Total locomotion was not affected. Total time spent moving in the EPM was similar between groups (P>0.05). (d) VNS treatment reduced startle responses. Following extinction, there was no difference in PTSD model rats versus AFC alone rats. Administration of VNS during extinction reduced startle amplitudes in PTSD model rats versus sham (*P<0.05) and in rats that underwent AFC alone versus sham (*P<0.05). AFC, auditory fear conditioning; EPM, elevated plus maze; PTSD, post-traumatic stress disorder; VNS, vagus nerve stimulation.
