Аннотация:The normal brain undergoes a substantial decrease of functional connections within resting-state networks during aging, but gender-related differences in functional connectivity remain largely unknown. The ε4 allele of the apolipoprotein E gene (ApoE) is well established risk factor for Alzheimer's disease (AD). The ApoE effect on AD risk is stronger in women than in men, but its mechanism is not completely understood. The aim of this study was to determine the possible gender-related differences of the alterations of brain functional connectivity in normal aging and to define the effect of ApoE genotype on theses alterations. We examined age-related differences in resting state functional connectivity assessed by interhemispheric EEG coherence in 141 non-demented volunteers (age range 20-80 years), subdivided into subgroups of those younger and older than 50 years of age and stratified by gender and ApoE genotype. All subjects were free of neurological or psychiatric conditions and underwent cognitive screening.
The results showed gender-related differences in resting state functional connectivity with women demonstrating greater interhemispheric coherence in younger age and higher coherence reduction during aging. The most prominent disruption of functional connectivity was found in the older female ApoE ε4 carriers.. The reduction of interhemispheric coherence of alpha activity in elderly subjects correlated with the worse performance in verbal memory test. The progressive decline in interhemispheric connectivity contributes to memory decrement and suggests the impact of age-related disconnection process in pathogenesis of AD in women carrying ApoE ε4 allele.