scholarly journals Topography of Movement-Related Delta and Theta Brain Oscillations

2021 ◽  
Author(s):  
János Körmendi ◽  
Eszter Ferentzi ◽  
Béla Weiss ◽  
Zoltán Nagy

AbstractThe aim of this study was to analyse the high density EEG during movement execution guided by visual attention to reveal the detailed topographic distributions of delta and theta oscillations. Twenty right-handed young subjects performed a finger tapping task, paced by a continuously transited repeating visual stimuli. Baseline corrected power of scalp current density transformed EEG was statistically assessed with cluster-based permutation testing. Delta and theta activities revealed differences in their spatial properties at the time of finger tapping execution. Theta synchronization showed a contralateral double activation in the parietal and fronto-central regions, while delta activity appeared in the central contralateral channels. Differences in the spatiotemporal topography between delta and theta activity in the course of movement execution were identified on high density EEG.

Nutrients ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 2235
Author(s):  
Alyann Otrante ◽  
Amal Trigui ◽  
Roua Walha ◽  
Hicham Berrougui ◽  
Tamas Fulop ◽  
...  

High-density lipoproteins (HDL) maintain cholesterol homeostasis through the role they play in regulating reverse cholesterol transport (RCT), a process by which excess cholesterol is transported back to the liver for elimination. However, RCT can be altered in the presence of cardiovascular risk factors, such as aging, which contributes to the increase in the incidence of cardiovascular diseases (CVD). The present study was aimed at investigating the effect of extra virgin olive oil (EVOO) intake on the cholesterol efflux capacity (CEC) of HDL, and to elucidate on the mechanisms by which EVOO intake improves the anti-atherogenic activity of HDL. A total of 84 healthy women and men were enrolled and were distributed, according to age, into two groups: 27 young (31.81 ± 6.79 years) and 57 elderly (70.72 ± 5.6 years) subjects. The subjects in both groups were given 25 mL/d of extra virgin olive oil (EVOO) for 12 weeks. CEC was measured using J774 macrophages radiolabeled with tritiated cholesterol ((3H) cholesterol). HDL subclass distributions were analyzed using the Quantimetrix Lipoprint® system. The HDL from the elderly subjects exhibited a lower level of CEC, at 11.12% (p < 0.0001), than the HDL from the young subjects. The CEC of the elderly subjects returned to normal levels following 12 weeks of EVOO intake. An analysis of the distribution of HDL subclasses showed that HDL from the elderly subjects were composed of lower levels of large HDL (L-HDL) (p < 0.03) and higher levels of small HDL (S-HDL) (p < 0.002) compared to HDL from the young subjects. A multiple linear regression analysis revealed a positive correlation between CEC and L-HDL levels (r = 0.35 and p < 0.001) as well as an inverse correlation between CEC and S-HDL levels (r = −0.27 and p < 0.01). This correlation remained significant even when several variables, including age, sex, and BMI as well as low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and glucose levels (β = 0.28, p < 0.002, and β = 0.24, p = 0.01) were accounted for. Consuming EVOO for 12 weeks modulated the age-related difference in the distribution of HDL subclasses by reducing the level of S-HDL and increasing the level of intermediate-HDL/large-HDL (I-HDL/L-HDL) in the elderly subjects. The age-related alteration of the CEC of HDL was due, in part, to an alteration in the distribution of HDL subclasses. A diet enriched in EVOO improved the functionality of HDL through an increase in I-HDL/L-HDL and a decrease in S-HDL.


1996 ◽  
Vol 174 ◽  
pp. 355-356 ◽  
Author(s):  
Simon F. Portegies Zwart

A significant depletion of red giants is observed in the central regions of post-collapsed globulars (Djorgovski et al., 1993) like M 15 (Stetson, 1991). A simple model shows that the depletion of red giants in the high-density cores of globular clusters can be understood in terms of mutual stellar collisions. Slightly outside the core stellar collisions are not frequent enough to explain the reduction in the observed number of red giants.


2007 ◽  
Vol 3 (S245) ◽  
pp. 161-164 ◽  
Author(s):  
Witold Maciejewski

AbstractIn central regions of non-axisymmetric galaxies high-resolution hydrodynamical simulations indicate spiral shocks, which are capable of transporting gas inwards. The efficiency of transport is lower at smaller radii, therefore instead of all gas dropping onto the galactic centre, a roughly uniform distribution of high-density gas develops in the gaseous nuclear spiral downstream from the shock, and the shear in gas is very low there. These are excellent conditions for star formation. This mechanism is likely to contribute to the process of (pseudo-) bulge formation.


2003 ◽  
Vol 37 ◽  
pp. 123-128 ◽  
Author(s):  
Donald E. Voigt ◽  
Richard B. Alley ◽  
Sridhar Anandakrishnan ◽  
Matthew K. Spencer

AbstractVigorous flow of central regions of Ice Stream C, West Antarctica, near the UpC camp ended about the year 1830, based on analysis of a firn and ice core taken at the camp. Ice-stream flow was characterized by repeated fracturing and healing, probably subsurface, especially near the onset of streaming flow. High longitudinal stresses caused fracturing, recrystallization of the ice and elongation of bubbles, and enhanced densification rates of high-density firn indicating power-law-creep behavior.


Motor Control ◽  
2019 ◽  
Vol 23 (4) ◽  
pp. 518-534
Author(s):  
Tomoko Aoki ◽  
Hayato Tsuda ◽  
Hiroshi Kinoshita

The purpose of this study was to examine finger motor function in terms of temporal and force characteristics during rapid single-finger tapping in older adults. Ten older and 10 young males performed maximum frequency tapping by the index, middle, ring, or little finger. Nontapping fingers were maintained in contact with designated keys during tasks. Key-contact force for each of the fingers was monitored using four force transducers. The older subjects had slower tapping rates of all fingers during single-finger tapping than the young subjects. The average forces exerted by the nontapping fingers were larger for the older subjects than for the young subjects during tapping with the ring and little fingers. The ranges of the nontapping finger forces were larger for the older subjects during tapping by the middle, ring, and little fingers than for the young subjects. Thus, the motor abilities of the fingers evaluated by rapid single-finger tapping decline in older adults compared with young adults in terms of both movement speed and finger independence.


2006 ◽  
Vol 243 (14) ◽  
pp. 3741-3753 ◽  
Author(s):  
M. S. Skolnick ◽  
D. Sanvitto ◽  
D. N. Krizhanovskii ◽  
A. P. D. Love ◽  
D. M. Whittaker ◽  
...  

2006 ◽  
Vol 243 (14) ◽  
pp. 3569-3569
Author(s):  
M. S. Skolnick ◽  
D. Sanvitto ◽  
D. N. Krizhanovskii ◽  
A. P. D. Love ◽  
D. M. Whittaker ◽  
...  

2003 ◽  
Vol 23 (5) ◽  
pp. 565-573 ◽  
Author(s):  
Axel Riecker ◽  
Wolfgang Grodd ◽  
Uwe Klose ◽  
Jorg B. Schulz ◽  
Klaus Gröschel ◽  
...  

Recent blood oxygenation level–dependent (BOLD) functional magnetic resonance imaging studies have shown a reduction of cerebral activation during aging, which may be associated with age-related changes of the cerebral vascular system. The authors used a global hypercapnic breath-holding challenge to define nonneuronal contributions to a significantly reduced activation in the primary sensorimotor cortex during finger tapping in a group of old (n = 6; mean age 65 years) compared with a group of young (n = 6; mean age 27 years) subjects. Within significantly activated voxels in both groups during finger tapping, the mean BOLD signal amplitudes were significantly smaller in the group of older subjects for both tasks. In those voxels showing significant activation only in young subjects during finger tapping, the response to hypercapnia was also greatly diminished in older subjects. The attenuated hypercapnic BOLD signal response in older subjects within this region suggests that age-dependent changes of the cerebral vasculature may alter the neuronal–vascular coupling. In older subjects, cerebral vessels may not react as effectively in response to a vasodilating stimulus, which will lead to differences in the number of voxels that pass a criterion threshold despite similar neuronal activation.


SLEEP ◽  
2020 ◽  
Vol 43 (Supplement_1) ◽  
pp. A307-A307
Author(s):  
A Valomon ◽  
K P Nakamura ◽  
I De Cuntis ◽  
E Kummerow ◽  
M Bazalakova ◽  
...  

Abstract Introduction Parasomnia episodes (PE) consist of abnormal behaviors during sleep. Using high-density EEG (HDEEG), we sought to quantify topographical differences in spectral power during PE in comparison to wake and sleep. Methods 17 adult subjects with a history of NREM sleep parasomnia underwent 256-electrode HDEEG recordings during recovery sleep after 25h of sleep deprivation. PE occurred either spontaneously or when triggered by a sound. Data preprocessing of PE, sleep and wake data included filtering at 1-25 Hz, careful epoch and channel selection, and adaptive mixture independent component analysis (AMICA). We compared topographies of delta (slow wave activity, or SWA) and theta power, alpha power, and beta/delta ratio (a marker of cortical arousal) between states using paired t-tests. All results were thresholded at p&lt;0.05 corrected for multiple comparison using statistical non parametric mapping (SNPM). Results Clean data were obtained in 26 PE arising out of N2/N3 sleep in 11 subjects. During PE, delta and theta power were significantly higher than during wake but lower than during sleep in central regions (at uncorrected p&lt;0.05 for sleep vs. PE delta power). Occipital alpha was lower during PE compared to wake, but higher during PE compared to sleep. Finally, beta/delta ratio values during PE were globally higher than in wake, but globally lower than during sleep. Conclusion The present results confirm and extend our previous findings of decreased SWA in central areas during baseline sleep in patients with NREM sleep PE. They suggest that higher cortical arousal in central regions may precipitate motor behaviors during PE. Alpha power and beta-delta ratio during PE were intermediate between sleep and wake, suggesting that PE are transitional states with an admixture of cortical arousal and cortical sleep. Future analyses will use source reconstruction to identify the cortical generators of observed scalp differences. Support This work was funded by the Swiss National Science Foundation and the Tiny Blue Dot foundation.


eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Petra Fischer ◽  
Alek Pogosyan ◽  
Damian M Herz ◽  
Binith Cheeran ◽  
Alexander L Green ◽  
...  

Gamma activity in the subthalamic nucleus (STN) is widely viewed as a pro-kinetic rhythm. Here we test the hypothesis that rather than being specifically linked to movement execution, gamma activity reflects dynamic processing in this nucleus. We investigated the role of gamma during fast stopping and recorded scalp electroencephalogram and local field potentials from deep brain stimulation electrodes in 9 Parkinson’s disease patients. Patients interrupted finger tapping (paced by a metronome) in response to a stop-signal sound, which was timed such that successful stopping would occur only in ~50% of all trials. STN gamma (60–90 Hz) increased most strongly when the tap was successfully stopped, whereas phase-based connectivity between the contralateral STN and motor cortex decreased. Beta or theta power seemed less directly related to stopping. In summary, STN gamma activity may support flexible motor control as it did not only increase during movement execution but also during rapid action-stopping.


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