(NCI) (Guillozet et al., 2003; Markesbery, 2010, 2006). The clinical concept of MCI was

(NCI) (Guillozet et al., 2003; Markesbery, 2010, 2006). The clinical concept of MCI was derived from memory clinics, which attracted milder cases of dementia, as well as longitudinal studies of elderly populations in which subjects were evaluated annually for cognitive status. Many of the subjects with earlier, milder cases of cognitive loss did not exhibit impairment in two cognitive domains, a criterion that was required for an NINDS/ADRDA diagnosis of AD established by McKhann and coworkers (1984). In the 1990’s, such cases were most frequently, but not always, characterized by an amnestic disorder and the term “Mild Cognitive Impairment” (MCI) was popularized by Petersen (1999). While memory disorder clinics reported that amnestic MCI (aMCI) was the most common form of MCI, it was clear that MCI along with other affected single cognitive domains comprised a small, but significant, component of this clinical presentation. Indeed, people with a clinical diagnosis of MCI comprise a heterogeneous cohort of which those who present solely with memory deficits are classifiedAuthor Manuscript Author Manuscript Author Manuscript Author ManuscriptNeuroscience. Author manuscript; available in PMC 2016 September 12.Mufson et al.Pageas single HIV-1 integrase inhibitor 2 site domain aMCI, while those who have a deficit in memory as well as other cognitive domains are categorized as multi-domain MCI (mdMCI) (Johnson et al., 2010; Petersen, 2003). Those with aMCI are at a higher risk of developing AD (Johnson et al., 2010; Petersen, 2003). However, some people clinically diagnosed with no cognitive impairment (NCI) or with MCI can exhibit SP and NFT pathology equal to or greater that that seen in mild to moderate AD dementia, challenging the pathologically-based idea that these lesions alone cause dementia (Mufson et al. 1999; Price et al. 2009, Markesbery 2010). Clinical pathological studies indicate that NFTs correlate better than and amyloid plaques with cognition in AD (Bierer et al., 1995; Nelson et al., 2012) However, The “amyloid cascade” hypothesis of AD (Hardy and Higgins GA, 1992) was revised recently to include soluble A oligomers (in addition to insoluble plaques) after multiple studies demonstrated their ability to impair synaptic function and memory (Lesne et al., 2006). Moreover, recent research indicates that there is a dynamic balance between “soluble” oligomeric and “insoluble” HMPL-013 site fibrillar A pools in the AD brain, with concentrations of soluble A species determining the rate of A aggregation in plaques, and plaque-aggregated A fibrils serving as a reservoir of soluble A in the interstitial fluid surrounding neuronal synapses (Koffie et al., 2009). Synaptic loss, a hallmark of the AD brain (Scheff et al., 1998, 2003, 2006), correlates with cognitive decline in many vulnerable regions, but not all affected areas (Scheff et al., 2006). In addition, there are deficits in glutamatergic (Hyman, 1987; Palmer et al., 1986; Cross et al., 1987; Hardy et al., 1987; Procter et al., 1987; Cowburn et al., 1988a, b), cholinergic (Davies and Mahoney, 1976; Whitehouse et al, 1982), serotonergic (Mann and Yates 1986), and noradrenergic (Adolfsson et al. 1979; Mann et al. 1983; Zarow et al. 2003; Grudzien et al. 2007; Braak and Del Tredici, 2011; Counts and Mufson, 2010) cortical innervation and as well as an up-regulation of endosomal/lysosomal autophagy molecules, which appear to precede plaque and tangle pathology (Cataldo et al., 1994; Ginsberg et al., 2010a; Nixon, 2005) in cor.(NCI) (Guillozet et al., 2003; Markesbery, 2010, 2006). The clinical concept of MCI was derived from memory clinics, which attracted milder cases of dementia, as well as longitudinal studies of elderly populations in which subjects were evaluated annually for cognitive status. Many of the subjects with earlier, milder cases of cognitive loss did not exhibit impairment in two cognitive domains, a criterion that was required for an NINDS/ADRDA diagnosis of AD established by McKhann and coworkers (1984). In the 1990’s, such cases were most frequently, but not always, characterized by an amnestic disorder and the term “Mild Cognitive Impairment” (MCI) was popularized by Petersen (1999). While memory disorder clinics reported that amnestic MCI (aMCI) was the most common form of MCI, it was clear that MCI along with other affected single cognitive domains comprised a small, but significant, component of this clinical presentation. Indeed, people with a clinical diagnosis of MCI comprise a heterogeneous cohort of which those who present solely with memory deficits are classifiedAuthor Manuscript Author Manuscript Author Manuscript Author ManuscriptNeuroscience. Author manuscript; available in PMC 2016 September 12.Mufson et al.Pageas single domain aMCI, while those who have a deficit in memory as well as other cognitive domains are categorized as multi-domain MCI (mdMCI) (Johnson et al., 2010; Petersen, 2003). Those with aMCI are at a higher risk of developing AD (Johnson et al., 2010; Petersen, 2003). However, some people clinically diagnosed with no cognitive impairment (NCI) or with MCI can exhibit SP and NFT pathology equal to or greater that that seen in mild to moderate AD dementia, challenging the pathologically-based idea that these lesions alone cause dementia (Mufson et al. 1999; Price et al. 2009, Markesbery 2010). Clinical pathological studies indicate that NFTs correlate better than and amyloid plaques with cognition in AD (Bierer et al., 1995; Nelson et al., 2012) However, The “amyloid cascade” hypothesis of AD (Hardy and Higgins GA, 1992) was revised recently to include soluble A oligomers (in addition to insoluble plaques) after multiple studies demonstrated their ability to impair synaptic function and memory (Lesne et al., 2006). Moreover, recent research indicates that there is a dynamic balance between “soluble” oligomeric and “insoluble” fibrillar A pools in the AD brain, with concentrations of soluble A species determining the rate of A aggregation in plaques, and plaque-aggregated A fibrils serving as a reservoir of soluble A in the interstitial fluid surrounding neuronal synapses (Koffie et al., 2009). Synaptic loss, a hallmark of the AD brain (Scheff et al., 1998, 2003, 2006), correlates with cognitive decline in many vulnerable regions, but not all affected areas (Scheff et al., 2006). In addition, there are deficits in glutamatergic (Hyman, 1987; Palmer et al., 1986; Cross et al., 1987; Hardy et al., 1987; Procter et al., 1987; Cowburn et al., 1988a, b), cholinergic (Davies and Mahoney, 1976; Whitehouse et al, 1982), serotonergic (Mann and Yates 1986), and noradrenergic (Adolfsson et al. 1979; Mann et al. 1983; Zarow et al. 2003; Grudzien et al. 2007; Braak and Del Tredici, 2011; Counts and Mufson, 2010) cortical innervation and as well as an up-regulation of endosomal/lysosomal autophagy molecules, which appear to precede plaque and tangle pathology (Cataldo et al., 1994; Ginsberg et al., 2010a; Nixon, 2005) in cor.