Moreover, we decided to inject SPON1 into both the hippocampus and entorhinal cortex (EC) to enhance hippocampal-dependent memory since the EC forms a neuronal network with the hippocampus and previous studies showed that brain-derived neurotrophic factor injection into the EC improved the hippocampal-dependent learning of the AD model [34,46]. The gene discussed is BDNF; the disease is Alzheimer disease.