HCAR1 and memory impairment: MCs, via theircommunication with GCs, have been implicated in various forms of mnemonic functionssuch as associative memory,36 pattern separation,37 and recall of memory sequences.38 Systemic administration of D-lactate and of the HCAR1 agonist 3,5-DHBA 15 minbefore performing inhibitory avoidance training showed memory impairments comparedto saline administration, suggesting the involvement of HCAR1 signaling in learningand memory.9 However, whether HCAR1 is involved in the dentate gyrus mnemonic processes isnot yet known.