BDNF and Cognitive impairment: Shi L et al. found that in microglia, butyrate attenuated radiation-induced cognitive deficits through the up-regulation of phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/cAMP-responsive element binding (CREB)/BDNF signaling pathway (Shi and Tu, 2015), which promotes long-term enhancement and synaptic plasticity, thereby improving memory function in patients.