scholarly journals Quasiperiodic Rhythms of the Inferior Olive

2018 ◽  
Author(s):  
Mario Negrello ◽  
Pascal Warnaar ◽  
Vincenzo Romano ◽  
Cullen B Owens ◽  
Sander Lindeman ◽  
...  
Keyword(s):  
Inferior Olive ◽  
Rhythmic Activity ◽  
Sensory Stimulation ◽  
Short Term ◽  
Subthreshold Oscillations ◽  
Electrophysiological Recordings ◽  
Long Term Changes ◽  
Inferior Olivary ◽  
Spiking Activity

Inferior olivary activity causes both short-term and long-term changes in cerebellar output underlying motor performance and motor learning. Many of its neurons engage in coherent subthreshold oscillations and are extensively coupled via gap junctions. Studies in reduced preparations suggest that these properties promote rhythmic, synchronized output. However, how these properties interact with synaptic inputs controlling inferior olivary output in intact, awake behaving animals is poorly understood. Here we combine electrophysiological recordings in awake mice with a novel and realistic tissue-scale computational model of the inferior olive to study the relative impact of intrinsic and extrinsic mechanisms governing its activity. Our data and model suggest that if subthreshold oscillations are present in the awake state, the period of these oscillations will be transient and variable. Accordingly, by using different temporal patterns of sensory stimulation, we found that complex spike rhythmicity was readily evoked but limited to short intervals of no more than a few hundred milliseconds and that the periodicity of this rhythmic activity was not fixed but dynamically related to the synaptic input to the inferior olive as well as to motor output. In contrast, in the long-term the average olivary spiking activity was not affected by the strength and duration of the sensory stimulation, while the level of gap junctional coupling determined the stiffness of the rhythmic activity in the olivary network during its dynamic response to sensory modulation. Thus, interactions between intrinsic properties and extrinsic inputs can explain the variations of spiking activity of olivary neurons, providing a conceptual framework for the creation of both the short-term and long-term changes in cerebellar output.

Short-Term and Long-Term Changes of Left Ventricular Volumes During Rate-Adaptive and Single-Rate Pacing

1989 ◽  
Vol 12 (12) ◽  
pp. 1863-1868 ◽  
Author(s):  
MEREDITH I. SEDNEY ◽  
ERIC WEIJERS ◽  
ERNST E. WALL ◽  
JEEEREY D. ADIPRANOTO ◽  
JAN CAMPS ◽  
...  
Keyword(s):  
Left Ventricular ◽  
Left Ventricular Volumes ◽  
Short Term ◽  
Ventricular Volumes ◽  
Long Term Changes ◽  
Rate Adaptive

scholarly journals On the peculiarities in the spin-down of isolated radio pulsars

2012 ◽  
Vol 8 (S291) ◽  
pp. 208-208
Author(s):  
Augustine Chukwude
Keyword(s):  
Radio Astronomy ◽  
Time Resolution ◽  
Local Phase ◽  
Astronomy Observatory ◽  
Radio Pulsars ◽  
Short Term ◽  
Radio Astronomy Observatory ◽  
Long Term Changes ◽  
Timing Data

AbstractWe investigate the spin-down behaviour of a sample of 25 radio pulsars on decadal timescales (~ 18 years) using a continuous timing data obtained over a period of at Hartebeesthoek Radio Astronomy Observatory (HartRAO). Particular attention is placed on achieving a better time resolution of both the short-term and long-term changes in pulsar spin-down using local phase-coherent measurements of the spin-down rates (). We demonstrate that the spin-down of radio pulsars is generally complicated by a superposition of processes that may or may not be related. Specifically, our results show that (i) for 7 pulsars, the observed spin-down variation is largely stochastic, characterized by random and sustained jumps in of varying amplitudes, (ii) for 9 objects, the spin-down evolution shows dominant monotonic variations in superimposed on short-term stochastic jumps in the parameter, and (iii) for the remaining 9 pulsars, the long-term spin-down evolution is non-monotonic, dominated by some systematic excursion in the measured spin-down rates.

scholarly journals Low-Amplitude Oscillations in the Inferior Olive: A Model Based on Electrical Coupling of Neurons With Heterogeneous Channel Densities

1997 ◽  
Vol 77 (5) ◽  
pp. 2736-2752 ◽  
Author(s):  
Yair Manor ◽  
John Rinzel ◽  
Idan Segev ◽  
Yosef Yarom
Keyword(s):  
Inferior Olive ◽  
Electrical Coupling ◽  
The Other ◽  
Sustained Oscillation ◽  
Large Coupling ◽  
Model Based ◽  
Subthreshold Oscillations ◽  
Coupling Current ◽  
Low Amplitude ◽  
Inferior Olivary

Manor, Yair, John Rinzel, Idan Segev, and Yosef Yarom. Low-amplitude oscillations in the inferior olive: a model based on electrical coupling of neurons with heterogeneous channel densities. J. Neurophysiol. 77: 2736–2752, 1997. The mechanism underlying subthreshold oscillations in inferior olivary cells is not known. To study this question, we developed a single-compartment, two-variable, Hodgkin-Huxley-like model for inferior olive neurons. The model consists of a leakage current and a low-threshold calcium current, whose kinetics were experimentally measured in slices. Depending on the maximal calcium and leak conductances, we found that a neuron model's response to current injection could be of four qualitatively different types: always stable, spontaneously oscillating, oscillating with injection of current, and bistable with injection of current. By the use of phase plane techniques, numerical integration, and bifurcation analysis, we subdivided the two-parameter space of channel densities into four regions corresponding to these behavioral types. We further developed, with the use of such techniques, an empirical rule of thumb that characterizes whether two cells when coupled electrically can generate sustained, synchronized oscillations like those observed in inferior olivary cells in slices, of low amplitude (0.1–10 mV) in the frequency range 4–10 Hz. We found that it is not necessary for either cell to be a spontaneous oscillator to obtain a sustained oscillation. On the other hand, two spontaneous oscillators always form an oscillating network when electrically coupled with any arbitrary coupling conductance. In the case of an oscillating pair of electrically coupled nonidentical cells, the coupling current varies periodically and is nonzero even for very large coupling values. The coupling current acts as an equalizing current to reconcile the differences between the two cells' ionic currents. It transiently depolarizes one cell and/or hyperpolarizes the other cell to obtain the regenerative response(s) required for the synchronized oscillation. We suggest that the subthreshold oscillations observed in the inferior olive can emerge from the electrical coupling between neurons with different channel densities, even if the inferior olive nucleus contains no or just a small proportion of spontaneously oscillating neurons.

Long-term reorganization of human motor cortex driven by short-term sensory stimulation

10.1038/264 ◽  
1998 ◽  
Vol 1 (1) ◽  
pp. 64-68 ◽  
Author(s):  
Shaheen Hamdy ◽  
John C. Rothwell ◽  
Qasim Aziz ◽  
Krishna D. Singh ◽  
David G. Thompson
Keyword(s):  
Motor Cortex ◽  
Sensory Stimulation ◽  
Short Term ◽  
Human Motor Cortex ◽  
Human Motor

scholarly journals Long- and Short-Term Changes of the Structure of Macrophytes in Lake Piaseczno in Relation to Land Use in the Łęczna-Włodawa Lakeland (Poland)

2013 ◽  
Vol 15 (2) ◽  
pp. 101-110
Author(s):  
Joana Sender ◽  
Weronika Maślanko
Keyword(s):  
Land Use ◽  
Aquatic Plants ◽  
Short Term ◽  
Main Interest ◽  
Central European ◽  
Macrophyte Communities ◽  
Long Term Changes ◽  
Very High ◽  
Macrophyte Structure

ABSTRACT The Łęczna-Włodawa Plain, known also as the Łęczna-Wlodawa Lakeland, lies within the territory of the largest subregion of the Polesie region, covering over 1,300 km2. The main interest of the Łęczna-Włodawa Lakeland is that it is the oldest in the Central European Lowlands group of about 68 lakes. Among such a large number of lakes there exist all trophic types. However, since the late 1950’s, enormous dynamics of change associated with the disappearance of oligo- and mesotrophic lakes and their transformation into eutrophic, even hypertrophic, lakes have been observed. One of the biocenotic elements of the lakes, which are indicators of these changes, is aquatic plants. The aim of this study was to determine the macrophyte structure of Piaseczno Lake and changes of land use in its surroundings. Piaseczno Lake still represents very high natural values. A reduction in the number of macrophyte communities, which occurred especially in 2008, was a consequence of the fast-growing recreation infrastructure. From 1976 until 2010 an area of recreation infrastructure in the studied area increased more than 3.5 times, and in the built-up area more than five times, as well as a doubling of the total length of the roads. Meanwhile the surface area of wetlands and peatbogs significantly decreased - more than 11 times. Long-term changes in the structure of the macrophyte communities show that the number of communities has varied in each year, probably as a consequence of changes in landuse. Analysis showed changes to the surfaces inhabited by macrophytes, which have decreased significantly over only four years, by more than 25%. However, the proportion of rush communities has increased.

scholarly journals Short-Term and Long-Term Changes in Corneal Power Are Not Correlated With Axial Elongation of the Eye Induced by Orthokeratology in Children

2018 ◽  
Vol 44 (4) ◽  
pp. 260-267 ◽  
Author(s):  
Jacinto Santodomingo-Rubido ◽  
César Villa-Collar ◽  
Bernard Gilmartin ◽  
Ramón Gutiérrez-Ortega
Keyword(s):  
Short Term ◽  
Corneal Power ◽  
Axial Elongation ◽  
Long Term Changes

scholarly journals 59 Short term elevation of cholesterol level in neonatal life and long term changes in aortic stiffness: insights from use of intravenous lipids

Heart ◽  
2011 ◽  
Vol 97 (Suppl 1) ◽  
pp. A37-A38
Author(s):  
A. J. Lewandowski ◽  
M. Lazdam ◽  
E. Davis ◽  
R. Poole ◽  
J. Diesch ◽  
...  
Keyword(s):  
Cholesterol Level ◽  
Aortic Stiffness ◽  
Short Term ◽  
Neonatal Life ◽  
Long Term Changes ◽  
Intravenous Lipids

scholarly journals Short-term changes in arterial inflammation predict long-term changes in atherosclerosis progression

2016 ◽  
Vol 44 (1) ◽  
pp. 141-150 ◽  
Author(s):  
Philip Joseph ◽  
Amorina Ishai ◽  
Venkatesh Mani ◽  
David Kallend ◽  
James H. F. Rudd ◽  
...  
Keyword(s):  
Short Term ◽  
Atherosclerosis Progression ◽  
Long Term Changes ◽  
Arterial Inflammation

scholarly journals Re-analysis of ground-based microwave ClO measurements from Mauna Kea, 1992 to early 2012

2013 ◽  
Vol 13 (17) ◽  
pp. 8643-8650 ◽  
Author(s):  
B. J. Connor ◽  
T. Mooney ◽  
G. E. Nedoluha ◽  
J. W. Barrett ◽  
A. Parrish ◽  
...  
Keyword(s):  
Atmospheric Composition ◽  
Composition Change ◽  
Major Focus ◽  
Short Term ◽  
Data Set ◽  
Long Term Changes ◽  
The Difference ◽  
Long Term Trend ◽  
Linear Decline

Abstract. We present a re-analysis of upper stratospheric ClO measurements from the ground-based millimeter-wave instrument from January 1992 to February 2012. These measurements are made as part of the Network for the Detection of Atmospheric Composition Change (NDACC) from Mauna Kea, Hawaii, (19.8° N, 204.5° E). Here, we use daytime and nighttime measurements together to form a day–night spectrum, from which the difference in the day and night profiles is retrieved. These results are then compared to the day–night difference profiles from the Upper Atmosphere Research Satellite (UARS) and Aura Microwave Limb Sounder (MLS) instruments. We also compare them to our previous analyses of the same data, in which we retrieved the daytime ClO profile. The major focus will be on comparing the year-to-year and long-term changes in ClO derived by the two analysis methods, and comparing these results to the long-term changes reported by others. We conclude that the re-analyzed data set has less short-term variability and exhibits a more constant long-term trend that is more consistent with other observations. Data from 1995 to 2012 indicate a linear decline of mid-stratospheric ClO of 0.64 ± 0.15% yr−1 (2σ).

SPOTing long-term changes in vegetation over short-term variability

2012 ◽  
Vol 28 (1) ◽  
pp. 2-24 ◽  
Author(s):  
Nisha Bao ◽  
Alex Lechner ◽  
Andrew Fletcher ◽  
Peter Erskine ◽  
David Mulligan ◽  
...  
Keyword(s):  
Short Term ◽  
Long Term Changes ◽  
Short Term Variability
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