Objective:To analyze the activation of primary somatosensory cortex(S1)neurons in post-traumatic stress disorder(PTSD)mice after tactile stimulation of whiskers and the changes of S1 cortical neurons in PTSD mice.Methods:Using the neuron cytoskeleton-associated protein(Arc)labeling strategy and immunofluorescence staining technique,the Arc of S1 cortical neurons in PTSD mice and control mice after whisker stimulation was marked and ob-served.By analyzing the difference in the spatial expression position of Arc labeled neurons and the number of positive cells,the activation level of S1 cortical neurons in the two groups was compared and analyzed.The pyramidal neurons of S1 cortex were labeled by sparse virus labeling method,and the number of dendrites and the morphology and number distribution of dendritic spines were compared between the two groups.Results:After whisker stimulation,it was found that Arc positive neurons were distributed from shallow layer to deep layer of S1,and more densely distributed in layersⅡ/Ⅲ and V.Compared with the control group,the number of positive neurons in different layers of the PTSD group was significantly increased.The results of cell morphology and structure analysis showed that,compared with the control group,the density of dendritic spines in layer Ⅱ/Ⅲ of mice with PTSD increased,and the number of mushroom dendrit-ic spines increased,while the number of filamentous pseudopod dendritic spines decreased.The number of dendritic spines of Si V layer mushroom type and slender type was higher,but the total number of dendritic spines was not sig-nificantly different.Conclusion:After whisker stimulation in PTSD mice,S1 neurons were over-activated,and the structure and morphology of neurons changed significantly.