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School of Public Health, Department of Epidemiology, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, USA.
Biological Psychiatry (Impact Factor: 10.26). 05/2005; 57(7):761-7. DOI: 10.1016/j.biopsych.2004.12.031
Source: PubMed


Attentional control of executive cognitive function (ECF) decreases in older individuals with Alzheimer Disease (AD). In order to examine early AD-related changes in the neural substrates of ECF attentional control, we measured activation dorsolateral prefrontal (dLPFC), posterior parietal (PPC), and anterior cingulate cortex (ACC) in adults with mild cognitively impairment (MCI) and in cognitively normal (CN) adults.
Functional magnetic resonance imaging analysis of brain activation in MCI (n = 8, mean age 79.5) and CN (n = 8 mean age 81.5) during increasing loads of attentional demands.
MCI and CN older adults performed with similar accuracy and reaction time. MCI had greater activation than CN in PPC (right p = .03 and left p = .05) and dlPFC areas (right p = .002 and left p = .004), while activation in ACC was similar in the two groups. Response to increasing loads of the task differed by group: MCI selectively engaged bilateral PPC (right p = .03, left p = .04), while CN subjects increased bilateral dlPFC activation (right p = .005 and left p = .02) and ACC activation (p = .04). Among MCI, greater load-related changes in PPC activity were associated with smaller load-related changes in accuracy rates (r = -.85, p = .07) and greater increases in reaction times (r = .97, p = .01). In CN subjects, load-related change in PPC activation was associated with load-related change in reaction time (r = .76, p = .02) but not with changes in accuracy rates.
PPC and dlPFC may show early functional changes associated with MCI.

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Available from: Caterina Rosano, Oct 04, 2015
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    • "In the alpha range, the posterior ERD was enlarged in dCON and MCI as compared to sCON, suggesting an increased mobilization of resources engaged for attention and working memory in these groups. The increase of memory-related cortical activity in MCI compared to controls was previously described using functional imaging [72] [73] [74]. In the same line, a 10–20 Hz ERD was identified in MCI cases contrasting with an ERS in control subjects during auditory working memory encoding [16]. "
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    ABSTRACT: Future treatments of Alzheimer's disease need the identification of cases at high risk at the preclinical stage of the disease before the development of irreversible structural damage. We investigated here whether subtle cognitive deterioration in a population of healthy elderly individuals could be predicted by EEG signals at baseline under cognitive activation. Continuous EEG was recorded in 97 elderly control subjects and 45 age-matched mild cognitive impairment (MCI) cases during a simple attentional and a 2-back working memory task. Upon 18-month neuropsychological follow-up, the final sample included 55 stable (sCON) and 42 deteriorated (dCON) controls. We examined the P1, N1, P3, and PNwm event-related components as well as the oscillatory activities in the theta (4-7 Hz), alpha (8-13 Hz), and beta (14-25 Hz) frequency ranges (ERD/ERS: event-related desynchronization/synchronization, and ITC: inter-trial coherence). Behavioral performance, P1, and N1 components were comparable in all groups. The P3, PNwm, and all oscillatory activity indices were altered in MCI cases compared to controls. Only three EEG indices distinguished the two control groups: alpha and beta ERD (dCON > sCON) and beta ITC (dCON < sCON). These findings show that subtle cognitive deterioration has no impact on EEG indices associated with perception, discrimination, and working memory processes but mostly affects attention, resulting in an enhanced recruitment of attentional resources. In addition, cognitive decline alters neural firing synchronization at high frequencies (14-25 Hz) at early stages, and possibly affects lower frequencies (4-13 Hz) only at more severe stages.
    Journal of Alzheimer's disease: JAD 07/2015; 47(2). DOI:10.3233/JAD-150111 · 4.15 Impact Factor
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    • "ode sites ( Eimer , 1996 ) . The neural sources of N2pc have been localized in extrastriate visual areas ( Luck et al . , 1997 ; Hopf et al . , 2000 ) . Considering the above mentioned deficits in allocation of attentional resources to target stimulus together with the increased interference exhibited by mdaMCI participants in Simon - type tasks ( Rosano et al . , 2005 ; Johns et al . , 2012 ; Cespón et al . , 2013a ; Pereiro et al . , 2014 ) , we can hypothesize that mechanisms related to prevent the cross - talk between the direction of the spatial attention and the response preparation ( i . e . , the N2cc correlate ) may be affected in mdaMCI . Also , some studies suggest that deficits in brain me"
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    ABSTRACT: Citation: Cespón J, Galdo-Álvarez S and Díaz F (2015) Inhibition deficit in the spatial tendency of the response in multiple-domain amnestic mild cognitive impairment. An event-related potential study. Front. Aging Neurosci. 7:68. Longitudinal studies have shown that a high percentage of people with amnestic mild cognitive impairment (MCI) develop Alzheimer's disease (AD). Prodromal AD is known to involve deficits in executive control processes. In the present study, we examined such deficits by recording EEG in 13 single-domain amnestic MCI (sdaMCI), 12 multiple-domain amnestic MCI (mdaMCI) and 18 healthy elderly (control group, CG) participants while they performed a Simon task. The Simon task demands deployment of executive processes because participants have to respond to non-spatial features of a lateralized stimulus and inhibit the more automatic spatial tendency of the response. We specifically focused on the negativity central contralateral (N2cc), an event-related potential (ERP) component related to brain activity that prevents the cross-talk between direction of spatial attention and manual response preparation. The reaction time (RT) was not significantly different among the three groups of participants. The percentage of errors (PE) was higher in mdaMCI than in CG and sdaMCI participants. In addition, N2cc latency was delayed in mdaMCI (i.e., delayed implementation of mechanisms for controlling the spatial tendency of the response). The N2cc latency clearly distinguished among mdaMCI and CG/sdaMCI participants (area under curve: 0.91). Longer N2cc was therefore associated with executive control deficits, which suggests that N2cc latency is a correlate of mdaMCI. Keywords: event-related potentials (ERP), mild cognitive impairment (MCI), negativity central contralateral (N2cc), negativity posterior contralateral (N2pc), inhibitory control, stimulus-response compatibility tasks (SRC)
    Frontiers in Aging Neuroscience 04/2015; 7. DOI:10.3389/fnagi.2015.00068 · 4.00 Impact Factor
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    • "While episodic memory is the primary early cognitive deficit, initial symptoms of memory loss may be accompanied by subtle changes in other neuropsychological domains, and research suggests that executive function tests can help predict later conversion to AD (Albert et al. 2001, 2007; Ready et al. 2003). Additionally, functional neuroimaging studies have shown abnormal brain activation of frontal lobe systems during MCI patients' performance of executive function tasks, and positive effects of psychopharmacological treatments such as cholinesterase inhibitors may be mediated via frontal systems (Rosano et al. 2005; Saykin et al. 2004). Identifying MCI patients who show declines in specific aspects of executive functioning, such as judgment, may be useful for studies investigating how such declines reflect changes in brain function over the course of illness. "
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    ABSTRACT: We investigated regional gray matter (GM) reduction as a predictor of judgment ability in 120 non-depressed older adults with varying degrees of cognitive complaints and/or impairment (including those with MCI and mild AD). Participants underwent neuropsychological assessment, including the Test of Practical Judgment (TOP-J), a recently developed instrument that evaluates judgment and problem solving related to safety, medical, social/ethical, and financial issues. Structural MR scanning included T1-weighted SPGR volumes acquired at 1.5 Tesla. We used voxel-based morphometry to analyze the relationship between GM density and TOP-J scores, controlling for age, education, gender, intracranial volume, verbal memory, and crystallized knowledge. Consistent with our hypothesis, judgment ability correlated with GM density in prefrontal regions (left inferior and superior frontal gyri). Findings extend previous observations of frontal involvement in higher-order cognitive abilities/executive functions and provide initial validation of the TOP-J's sensitivity to the integrity of these brain regions in individuals at risk for dementia.
    Brain Imaging and Behavior 06/2009; 3(2):212-219. DOI:10.1007/s11682-009-9063-6 · 4.60 Impact Factor
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