This structure is the chief source of mammalian theta rhythms.  
This structure is the chief source of mammalian theta rhythms.  The alveus portion of it forms a superficial layer between its CA region and the fimbria, and this structure is attached to the bottom of the amygdala. Antidepressants typically target this structure's dentate gyrus, which has a very high rate of neurogenesis. Damage to it results in anterograde amnesia, as this structure is necessary for the formation of new memories and general storage of long-term memories. For 10 points, name this part of the limbic system located in the medial temporal lobe, with a Greek name meaning "seahorse".
This structure is the chief source of mammalian theta rhythms.  
 hippocampus [prompt on “limbic system” until “alveus”; then do not accept it]