TABLE 3.

Prominent behavior changes in aging and underlying epigenetic code.

Epigenetic code/modification	Genes affected	Behavior changes/cognitive parameter affected	References
DNA cytosine methylation (MeC)	PP1; reelin; BDNF; calcineurin; Arc; Egr1; Fos; Homer1; Nr4a2	Conditioned fear memory; long-term associative memory formation and consolidation	Miller and Sweatt (2007), Bekinschtein et al. (2008), Lubin et al. (2008), Miller et al. (2010), Kaas et al. (2013)
Cytosine hydroxymethylation (OHMeC)	Tdg; Apobec1; Smug; Mbd4	Long-term associative memory formation and consolidation	Kaas et al. (2013)
H3 phosphorylation at Ser 10 and acetylation at K14	Not mentioned	Conditioned fear memory- long-term memory consolidation	Chwang et al. (2007)
H4 acetylation at K12	Fmn2	Associative learning, conditioned fear memory	Peleg et al. (2010)
H3 and H4 acetylation	Nr4a1; Nr4a2; NGFI-B	Contextual fear conditioned memory	Vecsey et al. (2007)
H3 acetylation at K9 and H4 acetylation	Not mentioned	Spatial learning and memory	Castellano et al. (2012)
H2B acetylation at Lys 5, 12, 15, 20 and H4 acetylation at Lys 12	bdnf, cFos, FosB and zif268	Spatial memory and consolidation	Bousiges et al. (2010)