Genetic polymorphisms of and risk (b) potential magnification by risk-related interactions or additive effects with age and (c) effect modification through stratification by (= 634; range: 53-95 years) for an EF latent variable. two polymorphisms on EF as Masitinib (AB1010) well a subsequent potential vulnerability conveyed with effect modification by and SNPs in the context of EF are available (e.g. Erickson et al. 2008 Miyajima et al. 2008 Savitz et al. 2006 Starr et al. 2007 We summarize the most relevant aspects of the proposed neural mechanisms as they are currently related to non-demented aging. The Val158Met rs4680 polymorphism at codon 158 on chromosome 22q11 increases COMT enzymatic activity that in turn decreases dopamine Masitinib (AB1010) levels particularly in the prefrontal cortex (Chen et al. 2004 This results in homozygotes for the Met allele having greater dopamine levels than the Val allele homozygotes. Thus non-demented older adults with any Val allele (Val-Val Val-Met) may be at higher risk for EF impairment than those with the Met-Met combination (Nagel et al. 2008 Wishart et al. 2011 However a variety of phenotypic associations have been observed for this polymorphism with such characteristics linked to the tonic-phasic dopamine hypothesis (Bilder et al. 2004 Egan et al. 2001 Regarding BDNF this factor is mainly present in the hippocampus and prefrontal cortex and it may play a role in such phenotypes as episodic memory global cognitive functioning and executive functions perhaps interactively additively or differentially by age and gender (Komulainen et al. 2008 Raz et al. 2009 Savitz et al. 2006 Although not quite to the extent as and could effectively intensify the deleterious effects of brain aging on select neurocognitive Masitinib ( AB1010) phenotypes. We examined two ways of representing vulnerability effects in this study (Gomar et al. 2011 Harris et al. in press; McClearn 2006 First we examined interactive or multiplicative (e.g. gene x gene interactions ending with gene x gene x age interactions) models to test moderating biological relationship between or (or more youthful age) would be at a lower risk for cognitive decrements. Conceivably removing even one risk factor could reduce some risk associated with either or risk alleles because at least one factor is moderating the others to produce the deleterious effect on EF. Second as an alternative representation of genetic-plus-aging vulnerability we performed parallel assessments of additive effects. This additive model of genetic risk included subsets and the full following calculation + + age. The additive model represents the notion that panels or combinations of risk biomarkers will influence cognitive phenotypic overall performance in normal aging and in early cognitive impairment (e.g. Gomar et al. 2011 even in Rabbit Polyclonal to OR13D1. the absence of impartial or multiplicative associations. An additive model (Purcell et al. 2009 Harris et al. in press; Verhaaren et al. 2013 could indicate that a non-risk (or protective) allele for or or more youthful age would effectively only eliminate the risk for one Masitinib (AB1010) of the risk factors but the risk associated with the other factors could still be present and influential. For convenience we refer to both interactive and additive effects as synergistic associations with EF throughout the paper. For both biological and cognitive reasons BDNF and COMT have been studied independently (rarely in addition or conversation) in the prefrontal cortex in non-demented older adults. For example BDNF may interact with COMT levels in the prefrontal cortex through basal ganglia-thalamocortical loops (e.g. Alexander et al. 1986 Masitinib (AB1010) Conceivably decreases in the secretion of BDNF may be associated with normal cognitive decline Masitinib (AB1010) and additional effects may further regulate the effects of cognitive deficits. In the Val66Met polymorphism Met homozygotes may be expected to produce selective cognitive deficits as compared to Val homozygotes. To our knowledge the present additive effects model has not been reported for these two SNPs in neurocognitive aging (for other examples observe Bertolino et al. 2006 Canli et al. 2008 McIntosh et al. 2013 Purcell et al. 2009 Verhaaren et al. 2013 However impartial and conversation effects of x conversation effect. However in a follow-up analysis adults with the combined risk alleles for and (Val service providers were visible in the older group of adults and this was modulated by whether individuals were carriers of the Met allele. Other examples are appearing in related literatures (e.g. Gomar et.