Alterations in neuronal morphology occur in primate cerebral cortex
نویسندگان
چکیده
during normal aging, vary depending on the neuronal type, region and cortical layer, and have been related to memory and cognitive impairment. We analyzed how such changes affect a specific subpopulation of cortical neurons forming long corticocortical projections from the superior temporal cortex to prefrontal area 46. These neurons were identified by retrograde transport in young and old macaque monkeys. Dendritic arbors of retrogradely labeled neurons were visualized in brain slices by intracellular injection of Lucifer Yellow, and reconstructed three-dimensionally using computer-assisted morphometry. Total dendritic length, numbers of segments, numbers of spines, and spine density were analyzed in layer III pyramidal neurons forming the projection considered. Sholl analysis was used to determine potential age-related changes in dendritic complexity. We observed statistically significant agerelated decreases in spine numbers and density on both apical and basal dendritic arbors in these projection neurons. On apical dendrites, changes in spine numbers occurred mainly on the proximal dendrites but spine density decreased uniformly among the different branch orders. On basal dendrites, spine numbers and density decreased preferentially on distal branches. Regressive dendritic changes were observed only in one particular portion of the apical dendrites, with the general dendritic morphology and extent otherwise unaffected by aging. In view of the fact that there is no neuronal loss in neocortex and hippocampus in old macaque monkeys, it is possible that the memory and cognitive decline known to occur in these animals is related to rather subtle changes in the morphological and molecular integrity of neurons subserving identifiable neocortical association circuits that play a critical role in cognition.
منابع مشابه
Antipsychotic treatment induces alterations in dendrite- and spine-associated proteins in dopamine-rich areas of the primate cerebral cortex.
BACKGROUND Mounting evidence indicates that long-term treatment with antipsychotic medications can alter the morphology and connectivity of cellular processes in the cerebral cortex. The cytoskeleton plays an essential role in the maintenance of cellular morphology and is subject to regulation by intracellular pathways associated with neurotransmitter receptors targeted by antipsychotic drugs. ...
متن کاملEffect of paraoxon on the synaptosomal GABA uptake in rat hippocampus and cerebral cortex
Introduction: Paraoxon (the neurotoxic metabolite of organophosphorus (OP) insecticide, parathion) exerts acute toxicity by inhibition of acetylcholinesterase (AChE), leading to the accumulation of acetylcholine in cholinergic synapses and hence overstimulation of the cholinergic system. Since, reports on changes in the level of γ- amino butyric acid (GABA) during OP-induced convulsion have bee...
متن کاملEffects of mild hypothermia on expression of NF-E2-related factor 2 and heme-oxygenase-1 in cerebral cortex and hippocampus after cardiopulmonary resuscitation in rats
Objective(s): The aim of this study was to investigate the effects of mild hypothermia on expression of NF-E2-related factor 2 (Nrf2) and heme-oxygenase-1 (HO-1) of rat cerebral cortex and hippocampus after cardiopulmonary resuscitation and further investigate the possible mechanism of action. Material and Methods:To copy an asphyxia heart arrest model, Sprague Dawley rats were randomly divided...
متن کاملCommentary In Aging, Is It Gray or White?
The article by Marner et al. in this issue of the Journal of Comparative Neurology reports that there is an extensive loss of myelinated fibers from the white matter of the human cerebral hemispheres during normal aging. It raises the possibility that changes in gray matter, and especially any loss of its component neurons, might not be the principal reason for the mild cognitive decline that a...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2003