In a postoperative trauma model, H2S reduced cognitive impairment in the Y-maze test; improved the recognition of new objects, and the Morris water maze, by increasing the expression of the synapsin-1 and PSD-95 proteins involved in the process of synaptic plasticity; and prevented a decrease in the density of synapses in the hippocampi of rats. The gene discussed is SYN1; the disease is Cognitive impairment.