Preferencje help
Polish version English version Język
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 5

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych:  cortical activity
help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
1
Content available remote

Cortical activity during hypoxic hyperventilation

100%
Pokorski M., Trojecka A., Marczak M., Wierzbicka A., Jernajczyk W.
Journal of Physiology and Pharmacology. Supplement
|
2003
|
tom 54
|
nr 1
29-34
This study seeks to determine the pattern of electroencephalogram changes during stimulatory ventilatory responses to acute progressive hypoxia. Electroencephalograms were recorded in the 10-20 electrode system during progressive poikilocapnic hypoxic tests based on the rebreathing routine. Healthy subjects were used for he study. A major finding was that hypoxia decreased the power spectra of the alpha activity. The decrease was surprisingly rapid and greater at mild hypoxic desaturation when pulmonary ventilation was about to pick up than during the maximum hypoxic hyperventilation. The possible relation of hypoxic decline in brain bioactivity to the manifestation of hypoxic hyperventilation remains to be elucidated in further studies.
2

Deterministic brain oscillations in the magnetoencephalogram

100%
Kowalik Z. J., Witte O. W.
Acta Neurobiologiae Experimentalis
|
2000
|
tom 60
|
nr 2
Determinism is a special property of some systems and is defined by its state-space behavior in which the trajectories in time never intersect. Whether or not determinism exists in brain activities is a question that may be resolved by analysis of the dynamical properties of the electroencephalogram (EEG) or magnetoencephalogram (MEG). We will show that even though there are strong nonstationarities in most brain behaviors, small epochs of deterministic dynamics can still be observed. We will also show that the local Lyapunov exponents are measures that can demonstrate smooth transitions into these deterministic states.
3
Content available remote

Electroencephalographic and respiratory activities during acute intermittent hypoxia in anesthetized rats

67%
Budzinska K., Ilasz R.
Journal of Physiology and Pharmacology. Supplement
|
2007
|
tom 58
|
nr 5
4

Anatomical correlates of the lateral hypothalamic influence on waking-sleep relationship in the rat

67%
Orzel-Gryglewska J., Jurkowlaniec E., Nowacka A., Tokarski J., Trojniar W.
Acta Neurobiologiae Experimentalis
|
2000
|
tom 60
|
nr 3
5

Beta activity: a carrier for visual attention

67%
Wrobel A.
Acta Neurobiologiae Experimentalis
|
2000
|
tom 60
|
nr 2
The alpha (8-13 Hz), beta (15-25 Hz) and gamma (30-60 Hz) bands of the EEG have been long studied clinically because of their putative functional importance. Old experimental results indicate that repetitive stimulation of the visual pathway evokes synchronous responses at the cortical level with a gain that depends on frequency; oscillations within relevant bands are less damped at subsequent processing levels than others. Our current results show in the cat that cortico-geniculate feedback has a build-in potentiation mechanism that operates at around the beta frequency and activates thalamic cells thus lowering the threshold for visual information transmission. We have also shown that enhanced beta activity is propagated along this feedback pathway solely during attentive visual behavior. This activity consists of 300-1,000 ms bursts that correlate in time with gamma oscillatory events. Beta-bursting activity spreads to all investigated visual centers, including the lateral posterior and pulvinar complex and higher cortical areas. Other supporting data are discussed that are concerned with the enhanced beta activity during attentive-like behavior of various species, including humans. Finally, we put forward a general hypothesis which attributes the appearance of oscillations within the alpha, beta and gamma bands to different activation states of the visual system. According to this hypothesis, alpha activity characterizes idle arousal of the system, while beta bursts shift the system to an attention state that consequently allows for gamma synchronization and perception.
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.