scholarly journals Two Novel Forms of ERG Oscillation in Drosophila: Age and Activity Dependence

2018 ◽  
Author(s):  
Atsushi Ueda ◽  
Scott Woods ◽  
Ian McElree ◽  
Tristan C.D.G. O’Harrow ◽  
Casey Inman ◽  
...  

AbstractOver an animal’s lifespan, neuronal circuits and systems often decline in an inherently heterogeneous fashion. To compare the age-dependent progression of changes in visual behavior with alterations in retinal physiology, we examined phototaxis and electroretinograms (ERGs) in a wild-type D. melanogaster strain (Canton-S) across their lifespan. In aged flies (beyond 50% median lifespan), we found a marked decline in phototaxis, while motor coordination was less disrupted, as indicated by relatively stronger negative geotaxis. These aged flies displayed substantially reduced ERG transient amplitudes while the receptor potentials (RP) remained largely intact. Using a repetitive light flash protocol, we serendipitously discovered two forms of activity-dependent oscillation in the ERG waveforms of young flies: “light-off’ and “light-on” oscillations. After repeated 500 ms light flashes, light-off oscillations appeared during the ERG off-transients (frequency: 50-120 Hz, amplitude: ~1 mV). Light-on oscillations (100-200 Hz, ~0.3 mV) were induced by a series of 50 ms flashes, and were evident during the ERG on-transients. Both forms of oscillation were observed in other strains of D. melanogaster(Oregon-R, Berlin), additional Drosophila species (funerbris, euronotus, hydei, americana), and were evoked by a variety of light sources. Both light-off and light-on oscillations were distinct from previously described ERG oscillations in visual mutants, such as rosA, in terms of location within the waveform and frequency. However, within rosA mutants, light-off oscillations, but not light-on oscillations could be recruited by the repetitive light flash protocol. Importantly though, we found that both forms of oscillation were rarely observed in aged flies. Although the physiological bases of these oscillations remain to be elucidated, they may provide important clues to age-related changes in neuronal excitability and synaptic transmission.

CNS Spectrums ◽  
2005 ◽  
Vol 10 (4) ◽  
pp. 298-308 ◽  
Author(s):  
Walter Zieglgänsberger ◽  
Achim Berthele ◽  
Thomas R. Tölle

AbstractNeuropathic pain is defined as a chronic pain condition that occurs or persists after a primary lesion or dysfunction of the peripheral or central nervous system. Traumatic injury of peripheral nerves also increases the excitability of nociceptors in and around nerve trunks and involves components released from nerve terminals (neurogenic inflammation) and immunological and vascular components from cells resident within or recruited into the affected area. Action potentials generated in nociceptors and injured nerve fibers release excitatory neurotransmitters at their synaptic terminals such as L-glutamate and substance P and trigger cellular events in the central nervous system that extend over different time frames. Short-term alterations of neuronal excitability, reflected for example in rapid changes of neuronal discharge activity, are sensitive to conventional analgesics, and do not commonly involve alterations in activity-dependent gene expression. Novel compounds and new regimens for drug treatment to influence activity-dependent long-term changes in pain transducing and suppressive systems (pain matrix) are emerging.


2017 ◽  
Vol 18 (1) ◽  
Author(s):  
Timo Jaakkola ◽  
Anthony Watt ◽  
Sami Kalaja

AbstractPurpose. Motor coordination is proposed to be a relatively stable age-related construct, unlikely to be influenced by aligned experiential factors such as intensive sport-specific training. The purpose of the study is to investigate if there are differences in motor coordination abilities among young artistic gymnasts, swimmers, and ice hockey players.Methods. The participants of the study were 508 female and 258 male adolescents (age, M = 12.80, SD = 1.10) comprising artistic gymnasts (n = 463), swimmers (n = 70), and ice hockey players (n = 233). The KTK-test protocol was used to analyse their gross motor coordination abilities.Results. The results of the study demonstrated that gymnasts scored better than ice hockey players and swimmers in the test of walking backwards along a beam, and better than ice hockey players in total motor coordination, hopping over an obstacle, and the test of moving sideways on wooden boards. However, ice hockey players scored higher than swimmers and gymnasts in the test of jumping from side to side. Subsequently, swimmers obtained better results in the test of moving sideways on wooden boards as compared with ice hockey players.Conclusions. The study results indicate that intensive sport-specific training may extend young athletes′ motor coordination characteristics in the ability areas representative of the sport in which they engage.


eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Antoine M Valera ◽  
Francesca Binda ◽  
Sophie A Pawlowski ◽  
Jean-Luc Dupont ◽  
Jean-François Casella ◽  
...  

Motor coordination is supported by an array of highly organized heterogeneous modules in the cerebellum. How incoming sensorimotor information is channeled and communicated between these anatomical modules is still poorly understood. In this study, we used transgenic mice expressing GFP in specific subsets of Purkinje cells that allowed us to target a given set of cerebellar modules. Combining in vitro recordings and photostimulation, we identified stereotyped patterns of functional synaptic organization between the granule cell layer and its main targets, the Purkinje cells, Golgi cells and molecular layer interneurons. Each type of connection displayed position-specific patterns of granule cell synaptic inputs that do not strictly match with anatomical boundaries but connect distant cortical modules. Although these patterns can be adjusted by activity-dependent processes, they were found to be consistent and predictable between animals. Our results highlight the operational rules underlying communication between modules in the cerebellar cortex.


2018 ◽  
Vol 115 (19) ◽  
pp. 5004-5009 ◽  
Author(s):  
Junsung Woo ◽  
Joo Ok Min ◽  
Dae-Si Kang ◽  
Yoo Sung Kim ◽  
Guk Hwa Jung ◽  
...  

Tonic inhibition in the brain is mediated through an activation of extrasynaptic GABAA receptors by the tonically released GABA, resulting in a persistent GABAergic inhibitory action. It is one of the key regulators for neuronal excitability, exerting a powerful action on excitation/inhibition balance. We have previously reported that astrocytic GABA, synthesized by monoamine oxidase B (MAOB), mediates tonic inhibition via GABA-permeable bestrophin 1 (Best1) channel in the cerebellum. However, the role of astrocytic GABA in regulating neuronal excitability, synaptic transmission, and cerebellar brain function has remained elusive. Here, we report that a reduction of tonic GABA release by genetic removal or pharmacological inhibition of Best1 or MAOB caused an enhanced neuronal excitability in cerebellar granule cells (GCs), synaptic transmission at the parallel fiber-Purkinje cell (PF-PC) synapses, and motor performance on the rotarod test, whereas an augmentation of tonic GABA release by astrocyte-specific overexpression of MAOB resulted in a reduced neuronal excitability, synaptic transmission, and motor performance. The bidirectional modulation of astrocytic GABA by genetic alteration of Best1 or MAOB was confirmed by immunostaining and in vivo microdialysis. These findings indicate that astrocytes are the key player in motor coordination through tonic GABA release by modulating neuronal excitability and could be a good therapeutic target for various movement and psychiatric disorders, which show a disturbed excitation/inhibition balance.


2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
Jihang Chen ◽  
Hoi Shan Wong ◽  
Pou Kuan Leong ◽  
Hoi Yan Leung ◽  
Wing Man Chan ◽  
...  

In the practice of traditional Chinese medicine, many Yang-tonic herbs have been used for retarding the decline in bodily function and delaying the onset of age-related diseases. Our earlier studies have demonstrated that Yang-invigorating herbs/formulations protect against oxidative injury in various organs and also extend the median lifespan in mice. This lifespan extension was associated with an upregulation of cellular antioxidant status including that of mitochondria whose functional capacity is also increased by “Yang-invigorating” herbs/formulations. In this paper, we propose that triterpenes and phytosterols, which are ubiquitously found in Yang-tonic herbs, may be the chemical entities responsible for enhancing mitochondrial functional and antioxidant capacity and thus the “Yang-invigorating” action. The biochemical mechanism underlying this “Yang-invigorating” action may involve a sustained production of low levels of mitochondrial reactive oxygen species (ROS) secondary to an increased activity of the electron transport chain, with the possible involvement of mitochondrial uncoupling. The increase in mitochondrial functional capacity can retard the decline in bodily function during aging, whereas the mitochondrial ROS production is instrumental in eliciting a glutathione antioxidant response via redox-sensitive signaling pathways, which can delay the onset of age-related diseases.


2010 ◽  
Vol 32 (11) ◽  
pp. 1889-1896 ◽  
Author(s):  
Elena Isaeva ◽  
Irina Lushnikova ◽  
Alina Savrasova ◽  
Galina Skibo ◽  
Gregory L. Holmes ◽  
...  

2019 ◽  
Vol 7 (2) ◽  
pp. 273-285 ◽  
Author(s):  
Sandra Silva-Santos ◽  
Amanda Santos ◽  
Michael Duncan ◽  
Susana Vale ◽  
Jorge Mota

Introduction: Adequate gross motor coordination is essential for children participating in age-related physical activities and has an important role in maintaining sufficient physical activity levels during the life course. Aim: To examine the association between moderate-to-vigorous physical activity (MVPA) and gross motor coordination during sedentary behavior in early childhood (ages 3–6 y). Methods: The sample comprised 209 children aged 3–6 y. Gross motor coordination was assessed according to the Movement Assessment Battery for Children (MABC-2). The battery to assess gross motor coordination comprised the aiming and catching, and balance components. MVPA was measured by accelerometry worn for 7 consecutive days (Monday to Sunday). Results: Our data indicated that 31.5% of the sample had low, 32.5% medium, and 36.0% high gross motor coordination. Multiple linear regression analysis showed that MVPA was positively associated with gross motor coordination, adjusted for gender and sedentary behavior. Conclusions: Preschoolers with high gross motor coordination spend more time in MVPA. Gross motor coordination development should therefore be a key strategy in childhood interventions aiming to promote physical activity.


2019 ◽  
Vol 21 (1) ◽  
pp. 120 ◽  
Author(s):  
Xiaolu Liu ◽  
Zhitao Feng ◽  
Lipeng Du ◽  
Yaguang Huang ◽  
Jinwen Ge ◽  
...  

Cerebral ischemia injury, the leading cause of morbidity and mortality worldwide, initiates sequential molecular and cellular pathologies that underlie ischemic encephalopathy (IE), such as ischemic stroke, Alzheimer disease (AD), Parkinson’s disease (PD), epilepsy, etc. Targeted therapeutic treatments are urgently needed to tackle the pathological processes implicated in these neurological diseases. Recently, accumulating studies demonstrate that microRNA-124 (miR-124), the most abundant miRNA in brain tissue, is aberrant in peripheral blood and brain vascular endothelial cells following cerebral ischemia. Importantly, miR-124 regulates a variety of pathophysiological processes that are involved in the pathogenesis of age-related IE. However, the role of miR-124 has not been systematically illustrated. Paradoxically, miR-124 exerts beneficial effects in the age-related IE via regulating autophagy, neuroinflammation, oxidative stress, neuronal excitability, neurodifferentiation, Aβ deposition, and hyperphosphorylation of tau protein, while it may play a dual role via regulating apoptosis and exerts detrimental effects on synaptic plasticity and axonal growth. In the present review, we thus focus on the paradoxical roles of miR-124 in age-related IE, as well as the underlying mechanisms. A great understanding of the effects of miR-124 on the hypoxic–ischemic brain will open new avenues for therapeutic approaches to protect against cerebral ischemia injury.


2015 ◽  
Vol 113 (1) ◽  
pp. 232-243 ◽  
Author(s):  
Attila Szücs ◽  
Ramon Huerta

The intrinsic excitability of neurons is known to be dynamically regulated by activity-dependent plasticity and homeostatic mechanisms. Such processes are commonly analyzed in the context of input-output functions that describe how neurons fire in response to constant levels of current. However, it is not well understood how changes of excitability as observed under static inputs translate to the function of the same neurons in their natural synaptic environment. Here we performed a computational study and hybrid experiments on rat bed nucleus of stria terminalis neurons to compare the two scenarios. The inward rectifying Kir current ( IKir) and the hyperpolarization-activated cation current ( Ih) were found to be considerably more effective in regulating the firing under synaptic inputs than under static stimuli. This prediction was experimentally confirmed by dynamic-clamp insertion of a synthetic inwardly rectifying Kir current into the biological neurons. At the same time, ionic currents that activate with depolarization were more effective regulating the firing under static inputs. When two intrinsic currents are concurrently altered such as those under homeostatic regulation, the effects in firing responses under static vs. dynamic inputs can be even more contrasting. Our results show that plastic or homeostatic changes of intrinsic membrane currents can shape the current step responses of neurons and their firing under synaptic inputs in a differential manner.


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