Fatigue-induced changes in diaphragmatic afferents and cortical activity in the cat

1992 ◽  
Vol 90 (2) ◽  
pp. 213-226 ◽  
Author(s):  
E. Balzamo ◽  
F. Lagier-Tessonnier ◽  
Y. Jammes
Keyword(s):  
Cortical Activity ◽  
Induced Changes

scholarly journals Cortical Oscillations during Gait: Wouldn’t Walking Be So Automatic?

2020 ◽  
Vol 10 (2) ◽  
pp. 90 ◽  
Author(s):  
Arnaud Delval ◽  
Madli Bayot ◽  
Luc Defebvre ◽  
Kathy Dujardin
Keyword(s):  
Posterior Parietal Cortex ◽  
Brain Activity ◽  
Muscular Activity ◽  
Cortical Activity ◽  
Muscular Contraction ◽  
Gait Pattern ◽  
Cortical Control ◽  
Time Frequency ◽  
Cortical Oscillations ◽  
Induced Changes

Gait is often considered as an automatic movement but cortical control seems necessary to adapt gait pattern with environmental constraints. In order to study cortical activity during real locomotion, electroencephalography (EEG) appears to be particularly appropriate. It is now possible to record changes in cortical neural synchronization/desynchronization during gait. Studying gait initiation is also of particular interest because it implies motor and cognitive cortical control to adequately perform a step. Time-frequency analysis enables to study induced changes in EEG activity in different frequency bands. Such analysis reflects cortical activity implied in stabilized gait control but also in more challenging tasks (obstacle crossing, changes in speed, dual tasks…). These spectral patterns are directly influenced by the walking context but, when analyzing gait with a more demanding attentional task, cortical areas other than the sensorimotor cortex (prefrontal, posterior parietal cortex, etc.) seem specifically implied. While the muscular activity of legs and cortical activity are coupled, the precise role of the motor cortex to control the level of muscular contraction according to the gait task remains debated. The decoding of this brain activity is a necessary step to build valid brain–computer interfaces able to generate gait artificially.

Transcranial brain stimulation and EEG/MEG

2021 ◽  
Author(s):  
Til Ole Bergmann ◽  
Leo Tomasevic ◽  
Hartwig Roman Siebner
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Brain Stimulation ◽  
Magnetic Stimulation ◽  
Neuronal Response ◽  
Cortical Activity ◽  
Conceptual Level ◽  
Transcranial Brain Stimulation ◽  
Experimental Approaches ◽  
Research Questions ◽  
Induced Changes

Noninvasive transcranial brain stimulation (NTBS) techniques, such as transcranial magnetic stimulation (TMS) and transcranial direct or alternating current stimulation (TDCS/TACS) can be combined with electroencephalography (EEG) and magnetoencephalography (MEG). The combination of NTBS and EEG/MEG can 1) inform brain stimulation (where, when, and how to stimulate), and 2) reveal aftereffects of stimulation induced changes in cortical activity, and interregional connectivity (offline approach), as well as the immediate neuronal response to the stimulation (online approach). While offline approaches allow to separate NTBS and EEG/MEG in space and time, online approaches require concurrent stimulation and recording. While TMS and MEG cannot be combined online, concurrent TMS-EEG as well as TDCS/TACS-MEG/EEG are feasible but pose a range of methodological challenges at the technical and conceptual level. This chapter provides an introduction into the principal experimental approaches and research questions that can be tackled by the combination of transcranial brain stimulation and EEG/MEG. We review the technical challenges arising from concurrent recordings as well as measures to avoid or remove stimulation artefacts. We also discuss the conceptual caveats and required control conditions.

scholarly journals Unexpected Terrain Induced Changes in Cortical Activity in Bipedal-Walking Rats

Biology ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 36
Author(s):  
Honghao Liu ◽  
Bo Li ◽  
Minjian Zhang ◽  
Chuankai Dai ◽  
Pengcheng Xi ◽  
...  
Keyword(s):  
Brain Activity ◽  
Cortical Activity ◽  
Bipedal Walking ◽  
Normal Walking ◽  
Double Support ◽  
Uneven Terrain ◽  
Band Power ◽  
The Right ◽  
Induced Changes ◽  
The Impact

Humans and other animals can quickly respond to unexpected terrains during walking, but little is known about the cortical dynamics in this process. To study the impact of unexpected terrains on brain activity, we allowed rats with blocked vision to walk on a treadmill in a bipedal posture and then walk on an uneven area at a random position on the treadmill belt. Whole brain EEG signals and hind limb kinematics of bipedal-walking rats were recorded. After encountering unexpected terrain, the θ band power of the bilateral M1, the γ band power of the left S1, and the θ to γ band power of the RSP significantly decreased compared with normal walking. Furthermore, when the rats left uneven terrain, the β band power of the bilateral M1 and the α band power of the right M1 decreased, while the γ band power of the left M1 significantly increased compared with normal walking. Compared with the flat terrain, the θ to low β (3–20 Hz) band power of the bilateral S1 increased after the rats contacted the uneven terrain and then decreased in the single- or double- support phase. These results support the hypothesis that unexpected terrains induced changes in cortical activity.

Interpretation of irradiation-induced changes in electron diffractograms and images of extinction contours at low temperatures

1984 ◽  
Vol 42 ◽  
pp. 268-269
Author(s):  
E. Knapek ◽  
H. Formanek ◽  
G. Lefranc ◽  
I. Dietrich
Keyword(s):  
Low Temperatures ◽  
Carbon Films ◽  
Organic Crystals ◽  
Wide Spread ◽  
Lens System ◽  
Preparation Conditions ◽  
Thin Carbon ◽  
Electron Diffractograms ◽  
Diffraction Patterns ◽  
Induced Changes

A few years ago results on cryoprotection of L-valine were reported, where the values of the critical fluence De i.e, the electron exposure which decreases the intensity of the diffraction reflections by a factor e, amounted to the order of 2000 + 1000 e/nm2. In the meantime a discrepancy arose, since several groups published De values between 100 e/nm2 and 1200 e/nm2 /1 - 4/. This disagreement and particularly the wide spread of the results induced us to investigate more thoroughly the behaviour of organic crystals at very low temperatures during electron irradiation.For this purpose large L-valine crystals with homogenuous thickness were deposited on holey carbon films, thin carbon films or Au-coated holey carbon films. These specimens were cooled down to nearly liquid helium temperature in an electron microscope with a superconducting lens system and irradiated with 200 keU-electrons. The progress of radiation damage under different preparation conditions has been observed with series of electron diffraction patterns and direct images of extinction contours.

Drug Induced Changes in Cell Organelles

1968 ◽  
Vol 26 ◽  
pp. 110-111
Author(s):  
Sarah A. Luse
Keyword(s):  
Clinical Medicine ◽  
Cell Organelles ◽  
Riboflavin Deficiency ◽  
Drug Induced ◽  
New Era ◽  
Health And Disease ◽  
In The Beginning ◽  
Cellular Pathology ◽  
Induced Changes ◽  
The Impact

In the mid-nineteenth century Virchow revolutionized pathology by introduction of the concept of “cellular pathology”. Today, a century later, this term has increasing significance in health and disease. We now are in the beginning of a new era in pathology, one which might well be termed “organelle pathology” or “subcellular pathology”. The impact of lysosomal diseases on clinical medicine exemplifies this role of pathology of organelles in elucidation of disease today.Another aspect of cell organelles of prime importance is their pathologic alteration by drugs, toxins, hormones and malnutrition. The sensitivity of cell organelles to minute alterations in their environment offers an accurate evaluation of the site of action of drugs in the study of both function and toxicity. Examples of mitochondrial lesions include the effect of DDD on the adrenal cortex, riboflavin deficiency on liver cells, elevated blood ammonia on the neuron and some 8-aminoquinolines on myocardium.

Digital x-ray mapping of nanometer-size supported bimetallic catalysts

1988 ◽  
Vol 46 ◽  
pp. 530-531
Author(s):  
L. T. Germinario
Keyword(s):  
Background Radiation ◽  
Metal Cluster ◽  
Single Element ◽  
Beam Diameter ◽  
X Rays ◽  
X Ray ◽  
Major Interest ◽  
Induced Changes

Understanding the role of metal cluster composition in determining catalytic selectivity and activity is of major interest in heterogeneous catalysis. The electron microscope is well established as a powerful tool for ultrastructural and compositional characterization of support and catalyst. Because the spatial resolution of x-ray microanalysis is defined by the smallest beam diameter into which the required number of electrons can be focused, the dedicated STEM with FEG is the instrument of choice. The main sources of errors in energy dispersive x-ray analysis (EDS) are: (1) beam-induced changes in specimen composition, (2) specimen drift, (3) instrumental factors which produce background radiation, and (4) basic statistical limitations which result in the detection of a finite number of x-ray photons. Digital beam techniques have been described for supported single-element metal clusters with spatial resolutions of about 10 nm. However, the detection of spurious characteristic x-rays away from catalyst particles produced images requiring several image processing steps.

Immunogold localization of calmodulin in root caps of the maize Cultivar Merit

1990 ◽  
Vol 48 (3) ◽  
pp. 674-675
Author(s):  
P.T. Nguyen ◽  
C. Uphoff ◽  
C.L. Stinemetz
Keyword(s):  
Calcium Binding ◽  
Calcium Transport ◽  
Primary Role ◽  
Immunogold Localization ◽  
Root Tips ◽  
Electrical Currents ◽  
Considerable Evidence ◽  
Maize Cultivar ◽  
Gravity Response ◽  
Induced Changes

Considerable evidence suggest that the calcium-binding protein calmodulin (CaM) may mediate calcium action and/or transport important in the gravity response of plants. Calmodulin is present in both shoots and roots and is capable of regulating calcium transport in plant vesicles. In roots calmodulin is concentrated in the tip, the gravisensing region of the root; and is reported to be closely associated with amyloplasts, organelles suggested to play a primary role in gravi-perception. Inhibitors of CaM such as chlorpromazine, calmidazolium, and compound 48/80 interfere with the gravitropic response of both snoots and roots. The magnitude of the inhibition corresponded well with the extent to which the drug binds to endogenous CaM. Compound 48/80 and calmidazolium block gravi-induced changes in electrical currents across root tips, a phenomenon thought to be associated with the sensing of the gravity stimulus.In this study, we have investigated the subcellular distribution of CaM in graviresponsive and non-graviresponsive root caps of the maize cultivar Merit.

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