engleski

High capability of human prefrontal cortex microcircuitry to maintain its structure during ageing

We analyzed changes in dendritic morphology and spine density on associative layer IIIc cortical projecting neurons and large layer V subcortical projecting pyramidal neurons to establish age- related changes within microcircuitries of the human prefrontal cortex (Brodmann area 9). Postmortem human brain tissue of adults was processed using the rapid Golgi method in two age groups: 38 – 64 years (n = 8) and 72 – 91 years, (n = 7). Neuropathological findings were unremarkable in all analyzed brain specimens. From each layer, the basal dendritic arbor and side dendritic branches from 10 – 15 well-impregnated pyramidal neurons per subject were three- dimensionally reconstructed using Neurolucida software. Soma size, total dendritic length, total segment number, individual segment length and spine density were quantitatively analyzed. Regarding layer V neurons, no significant differences were observed between adults and the elderly, either for dendritic morphology or for the spine density. The interindividual differences in the elderly group were however higher than in adults. Regarding associative layer IIIc pyramidal neurons, the mean values of spine density, on both side branches and basal dendrites, were 20–25% lower in the elderly than in adults (p = 0.07). In two aged cases the spine density was around mean level of adult and in the remaining aged subjects values were lower than in all adult subjects. These data show that the dendritic morphology and synaptic connectivity of the major classes of principal neurons in higher order associative areas are largely preserved in aging, while the connectivity of associative cortico-cortical layers is more prone to regression.

starenje ; piramidalni neuroni ; prefrontalna kora ; čovjek ; dendriti ; morfologija

nije evidentirano