Studies of a specific neuronal rearrangement that occurs in the mature rat nervous system have led to conclusions regarding the regulation of axonal growth in maturity and aging. In this brief review, the results of recent experiments are summarized and the general conclusions presented. One hypothesis that has emerged from these studies is that the extent of growth of one portion of a neuron's...

In the current experiment we conducted a multi-level analysis of age-related characteristics in the hippocampus of young adult (3 months), middle-aged (12 months), and old (24 months) Fisher 344xBrown Norway hybrid (FBNF1) rats. We examined the relationships between aging, hippocampus, and memory using a combination of behavioral, non-invasive magnetic resonance imaging and spectroscopy, and po...

The endoplasmic reticulum (ER) is an indispensable cellular organelle that remains highly active in neuronal cells. The ER bears the load of maintaining protein homeostasis in the cellular network by managing the folding of incoming nascent peptides; however, the stress imposed by physiological/environmental factors can cause ER dysfunctions that lead to the activation of ER unfolded protein re...

Although neuronal RNA oxidation is a prominent and established feature in age-associated neurodegenerative disorders such as Alzheimer disease (AD), oxidative damage to neuronal RNA in aging and in the transitional stages from normal elderly to the onset of AD has not been fully examined. In this study, we used an in situ approachto identify an oxidized RNA nucleoside 8-hydroxyguanosine (8OHG) ...

Stochastic resonance (SR) is fundamental to physical and biological processes. Here, we use a stochastic gain-tuning model to investigate interactions between aging-related increase of endogenous neuronal noise and external input noise in affecting SR. Compared to networks that have optimal system gain parameter of the activation function, networks with attenuated endogenous gain tuning at the ...

Brain aging is associated with declines in synaptic function that contribute to memory loss, including reduced postsynaptic response to neurotransmitters and decreased neuronal excitability. To understand how aging affects memory in a simple neural circuit, we studied neuronal proxies of memory for sensitization in mature vs. advanced age Aplysia californica (Aplysia). L-Glutamate- (L-Glu-) evo...

It has recently been described that aging in C. elegans is accompanied by the progressive development of morphological changes in the nervous system. These include novel outgrowths from the cell body or axonal process, as well as blebbing and beading along the length of the axon. The formation of these structures is regulated by numerous molecular players including members of the well-conserved...

Existing neurocomputational and empirical data link deficient neuromodulation of the fronto-parietal and hippocampal-striatal circuitries with aging-related increase in processing noise and declines in various cognitive functions. Specifically, the theory of aging neuronal gain control postulates that aging-related suboptimal neuromodulation may attenuate neuronal gain control, which yields com...

Caenorhabditis elegans is a powerful model for analysis of the conserved mechanisms that modulate healthy aging. In the aging nematode nervous system, neuronal death and/or detectable loss of processes are not readily apparent, but because dendrite restructuring and loss of synaptic integrity are hypothesized to contribute to human brain decline and dysfunction, we combined fluorescence microsc...