scholarly journals Spontaneous fluctuations in a magnetic Fe/Gd skyrmion lattice

2021 ◽  
Vol 3 (3) ◽  
Author(s):  
M. H. Seaberg ◽  
B. Holladay ◽  
S. A. Montoya ◽  
X. Y. Zheng ◽  
J. C. T. Lee ◽  
...  
Keyword(s):  
Spontaneous Fluctuations

MRI of spontaneous fluctuations after acute cerebral ischemia in nonhuman primates

2007 ◽  
Vol 26 (4) ◽  
pp. 1112-1116 ◽  
Author(s):  
Yutong Liu ◽  
Helen D'Arceuil ◽  
Julian He ◽  
Mike Duggan ◽  
Gilberto Gonzalez ◽  
...  
Keyword(s):  
Cerebral Ischemia ◽  
Nonhuman Primates ◽  
Acute Cerebral Ischemia ◽  
Spontaneous Fluctuations

Sleep-dependent changes in the coupling between heart period and blood pressure in human subjects

2008 ◽  
Vol 294 (5) ◽  
pp. R1686-R1692 ◽  
Author(s):  
Alessandro Silvani ◽  
Daniela Grimaldi ◽  
Stefano Vandi ◽  
Giorgio Barletta ◽  
Roberto Vetrugno ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Eye Movement ◽  
Sleep Disordered Breathing ◽  
Human Subjects ◽  
Rapid Eye Movement Sleep ◽  
Heart Period ◽  
Low Frequencies ◽  
Feed Forward ◽  
Finger Blood Pressure ◽  
Spontaneous Fluctuations

We investigated whether in human subjects, the pattern of coupling between the spontaneous fluctuations of heart period (HP) and those of systolic blood pressure (SBP) differs among wake-sleep states. Polysomnographic recordings and finger blood pressure measurements were performed for 48 h in 15 nonobese adults without sleep-disordered breathing. The cross-correlation function (CCF) between the fluctuations of HP and SBP at frequencies <0.15 Hz was computed during quiet wakefulness (QW), light (stages 1 and 2) and deep (stages 3 and 4) nonrapid-eye-movement sleep (NREMS), and rapid-eye-movement sleep (REMS). A positive correlation between HP and the previous SBP values, which is the expected result of baroreflex feedback control, was observed in the sleep states but not in QW. In deep NREMS, the maximum CCF value was significantly higher than in any other state, suggesting the greatest baroreflex contribution to the coupling between HP and SBP. A negative correlation between HP and the subsequent SBP values was also observed in each state, consistent with the mechanical feed-forward action of HP on SBP and with central autonomic commands. The contribution of these mechanisms to the coupling between HP and SBP, estimated from the minimum CCF value, was significantly lower in deep NREMS than either in light NREMS or QW. These results indicate that the pattern of coupling between HP and SBP at low frequencies differs among wake-sleep states in human subjects, with deep NREMS entailing the highest feedback contribution of the baroreflex and a low effectiveness of feed-forward mechanisms.

Properties of the Spontaneous Fluctuations in Cortical Oxygen Pressure

1984 ◽  
pp. 231-239 ◽  
Author(s):  
J. Manil ◽  
R. H. Bourgain ◽  
M. Van Waeyenberge ◽  
F. Colin ◽  
E. Blockeel ◽  
...  
Keyword(s):  
Oxygen Pressure ◽  
Cortical Oxygen Pressure ◽  
Spontaneous Fluctuations

scholarly journals Top-down coordination of local cortical state during selective attention

2020 ◽  
Author(s):  
Jochem van Kempen ◽  
Marc A. Gieselmann ◽  
Michael Boyd ◽  
Nicholas A. Steinmetz ◽  
Tirin Moore ◽  
...  
Keyword(s):  
Selective Attention ◽  
Cortical Excitability ◽  
Brain Regions ◽  
Global Changes ◽  
Top Down ◽  
Visual Hierarchy ◽  
Tightly Coupled ◽  
State Coordination ◽  
And Behavior ◽  
Spontaneous Fluctuations

AbstractSpontaneous fluctuations in cortical excitability influence sensory processing and behavior. These fluctuations, long known to reflect global changes in cortical state, were recently found to be modulated locally within a retinotopic map during spatially selective attention. We found that periods of vigorous (On) and faint (Off) spiking activity, the signature of cortical state fluctuations, were coordinated across brain areas along the visual hierarchy and tightly coupled to their retinotopic alignment. During top-down attention, this interareal coordination was enhanced and progressed along the reverse cortical hierarchy. The extent of local state coordination between areas was predictive of behavioral performance. Our results show that cortical state dynamics are shared across brain regions, modulated by cognitive demands and relevant for behavior.One Sentence SummaryInterareal coordination of local cortical state is retinotopically precise and progresses in a reverse hierarchical manner during selective attention.

scholarly journals Spontaneous Fluctuations and Non-linear Ignitions: Two Dynamic Faces of Cortical Recurrent Loops

Neuron ◽  
2015 ◽  
Vol 88 (1) ◽  
pp. 194-206 ◽  
Author(s):  
Clément Moutard ◽  
Stanislas Dehaene ◽  
Rafael Malach
Keyword(s):  
Dynamic Faces ◽  
Non Linear ◽  
Spontaneous Fluctuations
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