scholarly journals Hippocampal theta, gamma, and theta-gamma coupling: effects of aging, environmental change, and cholinergic activation

2013 ◽  
Vol 109 (7) ◽  
pp. 1852-1865 ◽  
Author(s):  
Tara K. Jacobson ◽  
Matthew D. Howe ◽  
Brandy Schmidt ◽  
James R. Hinman ◽  
Monty A. Escabí ◽  
...  
Keyword(s):  
Information Processing ◽  
Hippocampal Neurons ◽  
Gamma Oscillations ◽  
Major Influence ◽  
Aging Effects ◽  
Memory Impairments ◽  
Age Related ◽  
Behavioral Situation ◽  
Effects Of Aging ◽  
Hippocampal Theta

Hippocampal theta and gamma oscillations coordinate the timing of multiple inputs to hippocampal neurons and have been linked to information processing and the dynamics of encoding and retrieval. One major influence on hippocampal rhythmicity is from cholinergic afferents. In both humans and rodents, aging is linked to impairments in hippocampus-dependent function along with degradation of cholinergic function. Cholinomimetics can reverse some age-related memory impairments and modulate oscillations in the hippocampus. Therefore, one would expect corresponding changes in these oscillations and possible rescue with the cholinomimetic physostigmine. Hippocampal activity was recorded while animals explored a familiar or a novel maze configuration. Reexposure to a familiar situation resulted in minimal aging effects or changes in theta or gamma oscillations. In contrast, exploration of a novel maze configuration increased theta power; this was greater in adult than old animals, although the deficit was reversed with physostigmine. In contrast to the theta results, the effects of novelty, age, and/or physostigmine on gamma were relatively weak. Unrelated to the behavioral situation were an age-related decrease in the degree of theta-gamma coupling and the fact that physostigmine lowered the frequency of theta in both adult and old animals. The results indicate that age-related changes in gamma and theta modulation of gamma, while reflecting aging changes in hippocampal circuitry, seem less related to aging changes in information processing. In contrast, the data support a role for theta and the cholinergic system in encoding and that hippocampal aging is related to impaired encoding of new information.

scholarly journals Neurophysiological effects of aging: A P200 ERP study

2018 ◽  
Vol 9 (1) ◽  
pp. 61-66 ◽  
Author(s):  
Ali K. Bourisly ◽  
Ali Shuaib
Keyword(s):  
High Probability ◽  
Age Groups ◽  
Event Related Potential ◽  
Aging Effects ◽  
Age Related ◽  
Significant Difference ◽  
Low Probability ◽  
Effects Of Aging ◽  
Healthy Participants ◽  
Two Age Groups

Abstract Age-related effects were studied in 14 younger (M = 34 years) and 14 (M = 47 years) older healthy participants. Event-related potential (ERP) recording was done using a 256-channel EEG system. Results indicated that ERP is affected by advanced age. There was a significant difference in P200 mean latency between the younger participants and older participants for the target (low-probability) stimuli, but no such significance was evident for the P200 mean latency during the presentation of the standard (high-probability) stimuli. As for the P200 mean peak amplitude, the results for the target (low-probability) stimuli did show a significant difference between the two age groups, while the results for the standard (high-probability) stimuli did not show any significant difference between the two age groups. The results of this study are explained in light of aging effects on attentional recruitment and frontal lobe intactness.

scholarly journals Interneuronal mechanisms of hippocampal theta oscillations in a full-scale model of the rodent CA1 circuit

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Marianne J Bezaire ◽  
Ivan Raikov ◽  
Kelly Burk ◽  
Dhrumil Vyas ◽  
Ivan Soltesz
Keyword(s):  
Information Processing ◽  
Theta Rhythm ◽  
Gamma Oscillations ◽  
Full Scale ◽  
Theta Oscillations ◽  
Data Driven ◽  
Scale Model ◽  
Hippocampal Theta Rhythm ◽  
Ca1 Area ◽  
Hippocampal Theta

The hippocampal theta rhythm plays important roles in information processing; however, the mechanisms of its generation are not well understood. We developed a data-driven, supercomputer-based, full-scale (1:1) model of the rodent CA1 area and studied its interneurons during theta oscillations. Theta rhythm with phase-locked gamma oscillations and phase-preferential discharges of distinct interneuronal types spontaneously emerged from the isolated CA1 circuit without rhythmic inputs. Perturbation experiments identified parvalbumin-expressing interneurons and neurogliaform cells, as well as interneuronal diversity itself, as important factors in theta generation. These simulations reveal new insights into the spatiotemporal organization of the CA1 circuit during theta oscillations.

scholarly journals Contrasting effects of aging on the expression of transposons, the piRNA machinery and mitochondrial transcripts in the Drosophila ovary

2018 ◽  
Author(s):  
Alexandra A. Erwin ◽  
Justin P. Blumenstiel
Keyword(s):  
Germ Line ◽  
Epigenetic Factors ◽  
Sequencing Data ◽  
Aging Effects ◽  
Relative Contribution ◽  
Age Related ◽  
Epigenetic Aging ◽  
Egg Chambers ◽  
Mitochondrial Transcripts ◽  
Effects Of Aging

ABSTRACTRedistribution of heterochromatin during aging has been linked to the de-repression of transposable elements and an overall loss of gene regulation in the soma. Whether or not epigenetic factors such as heterochromatin marks are perturbed in reproductive and germline tissues is of particular interest because some epigenetic factors are known to transmit across generations. Additionally, the relative contribution of factors intrinsic or extrinsic to the germ line have in reproductive decline remains unknown. Using mRNA sequencing data from late stage egg chambers in Drosophila melanogaster, we show that age-related expression changes occur in genes residing in heterochromatin, particularly on the largely heterochromatic 4th chromosome. In addition, we identify an increase in expression of the piRNA machinery. We further identify a striking age-related reduction in mitochondrial transcripts that we can attribute to the somatic tissues. Other than a modest increase in overall TE expression in the aging germline, we find no global TE de-repression in reproductive tissues. Rather, the observed effects of aging on TEs are primarily strain and family specific. These results indicate unique responses in somatic versus germline tissue with regards to epigenetic aging effects and suggest that the global loss of TE control observed in other studies may be specific to certain tissues, genetic backgrounds and TE family. This study also demonstrates that while age-related effects can be maternally transmitted, the germline is generally robust to age-related changes.

Age and Information Processing

1997 ◽  
Vol 2 (3) ◽  
pp. 247-257 ◽  
Author(s):  
István Czigler ◽  
Gergely Csibra ◽  
Ágnes Ambró
Keyword(s):  
Information Processing ◽  
Event Related Potentials ◽  
The Elderly ◽  
Human Information Processing ◽  
Attentional Processes ◽  
Age Related ◽  
Related Potentials ◽  
Effects Of Aging ◽  
Identification Processes ◽  
The Brain

This paper reviews our recent studies on the effects of aging on human information processing. In these studies the event-related potentials of the brain (ERPs) recorded in visual discrimination tasks were compared in younger and older groups of subjects in four experiments. We obtained a slight age-related delay of the NA component of the ERP. This component is a correlate of elementary pattern-identification processes. Obvious latency differences appeared on the anterior positivity, selection negativity, and N2b components in tasks where the target stimuli were defined by two stimulus characteristics. These components are correlates of attentional processes, i.e., the results support the view emphasizing age-related decline of the attentional processes. In the elderly the late positivity was less sensitive to stimulus probability, and in the older groups this component was more evenly distributed over the scalp. These results are considered as an indication that the structure of stimulus sequences was less efficiently represented in the older subjects.

scholarly journals Modeling human age-associated increase in Gadd45γ expression leads to spatial recognition memory impairments in young adult mice

2020 ◽  
Author(s):  
David V.C. Brito ◽  
Kubra Gulmez Karaca ◽  
Janina Kupke ◽  
Franziska Mudlaff ◽  
Benjamin Zeuch ◽  
...  
Keyword(s):  
Young Adult ◽  
Hippocampal Neurons ◽  
Molecular Mechanisms ◽  
Memory Impairments ◽  
Adult Mice ◽  
Age Related ◽  
Mouse Hippocampus ◽  
Age Dependent ◽  
And Function ◽  
Dependent Processes

AbstractAging is associated with the progressive decay of cognitive function. Hippocampus-dependent processes, such as the formation of spatial memory, are particularly vulnerable to aging. Currently, the molecular mechanisms responsible for age-dependent cognitive decline are largely unknown. Here, we investigated the expression and function of the growth arrest DNA damage gamma (Gadd45γ) during aging and cognition. We report that Gadd45γ expression is increased in the hippocampus of aged humans and that Gadd45γ overexpression in the young adult mouse hippocampus compromises cognition. Moreover, Gadd45γ overexpression in hippocampal neurons disrupted CREB signaling and the expression of well-established activity-regulated genes. This work shows that Gadd45γ expression is tightly controlled in the hippocampus and its disruption may be a mechanism contributing to age-related cognitive impairments observed in humans.

scholarly journals Interneuronal mechanisms of hippocampal theta oscillation in full-scale model of the CA1 circuit

2016 ◽  
Author(s):  
Marianne J. Bezaire ◽  
Ivan Raikov ◽  
Kelly Burk ◽  
Dhrumil Vyas ◽  
Ivan Soltesz
Keyword(s):  
Information Processing ◽  
Theta Rhythm ◽  
Gamma Oscillations ◽  
Full Scale ◽  
Theta Oscillations ◽  
Data Driven ◽  
Scale Model ◽  
Hippocampal Theta Rhythm ◽  
Ca1 Area ◽  
Hippocampal Theta

AbstractThe hippocampal theta rhythm plays important roles in information processing; however, the mechanisms of its generation are not well understood. We developed a data-driven, supercomputer-based, full-scale (1:1) model of the CA1 area and studied its interneurons during theta oscillations. Theta rhythm with phase-locked gamma oscillations and phase-preferential discharges of distinct in terneuronal types spontaneously emerged from the isolated CA1 circuit without rhythmic inputs. Perturbation experiments identified parvalbumin-expressing interneurons and neurogliaform cells, as well as interneuronal diversity itself, as important factors in theta generation. These simulations reveal new insights into the spatiotemporal organization of the CA1 circuit during theta oscillations.

scholarly journals Single-neuron dynamical effects of dendritic pruning implicated in aging and neurodegeneration: towards a measure of neuronal reserve

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Christoph Kirch ◽  
Leonardo L. Gollo
Keyword(s):  
Structural Changes ◽  
Dynamic Range ◽  
Multiple Scales ◽  
Gray Matter Volume ◽  
Neuronal Morphology ◽  
Aging Effects ◽  
Neuronal Dynamics ◽  
Age Related ◽  
Consumption Energy ◽  
Effects Of Aging

AbstractAging is a main risk factor for neurodegenerative disorders including Alzheimer's disease. It is often accompanied by reduced cognitive functions, gray-matter volume, and dendritic integrity. Although age-related brain structural changes have been observed across multiple scales, their functional implications remain largely unknown. Here we simulate the aging effects on neuronal morphology as dendritic pruning and characterize its dynamical implications. Utilizing a detailed computational modeling approach, we simulate the dynamics of digitally reconstructed neurons obtained from Neuromorpho.org. We show that dendritic pruning affects neuronal integrity: firing rate is reduced, causing a reduction in energy consumption, energy efficiency, and dynamic range. Pruned neurons require less energy but their function is often impaired, which can explain the diminished ability to distinguish between similar experiences (pattern separation) in older people. Our measures indicate that the resilience of neuronal dynamics is neuron-specific, heterogeneous, and strongly affected by dendritic topology and the position of the soma. Based on the emergent neuronal dynamics, we propose to classify the effects of dendritic deterioration, and put forward a topological measure of “neuronal reserve” that quantifies the resilience of neuronal dynamics to dendritic pruning. Moreover, our findings suggest that increasing dendritic excitability could partially mitigate the dynamical effects of aging.

scholarly journals Aging Effects on Gut Microbiota in SAMP8 Mice

Proceedings ◽  
2020 ◽  
Vol 61 (1) ◽  
pp. 25
Author(s):  
Lluïsa Miró ◽  
Miquel Moretó ◽  
Concepció Amat ◽  
Javier Polo ◽  
Anna Pérez-Bosque
Keyword(s):  
Diversity Index ◽  
Bacterial Species ◽  
Fold Increase ◽  
Illumina Miseq ◽  
Fecal Microbiota ◽  
Aging Effects ◽  
Age Related ◽  
Genomic Study ◽  
Gut Mucosa ◽  
Effects Of Aging

We have studied the effects of aging on the fecal microbiota composition in the senescence-accelerated prone mice SAMP8 strain. We compared animals two, four, and six months old. Feces were collected at the end of each period and a genomic study was carried out on fecal DNA using the Illumina MiSeq analyzer. The Shannon diversity index showed similar values along this period and the number of species was neither affected by aging. The phylum Verrucobacteria went up with age, showing a seven-fold increase at six months, compared to two-month old mice. At the family level, changes observed between two and six months of age involved significant increases in Bacteroidaceae (q < 0.001) and strong reductions in Lactobacillaceae (q < 0.0001) and Prevotellaceae (q < 0.05); at the genus level, there was a significant reduction in probiotic Lactobacillus. At the species level, we observed an age-related reduction in Lactobacillus hayakitensis, a species involved in mucosal immune homeostasis, and in Blautia hansenii, which provides protection against Clostridium difficile infection. Interestingly, aging increases Parabacteroides goldsteiini, which is involved in the regulation of the TLR4 pathway. These results support the view that aging results in the proliferation of bacterial species that are associated with the immune deterioration of the gut mucosa.

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