scholarly journals PROTECTIVE MECHANISMS AGAINST HYPOXIA IN DIVING SIMULATION IN SWIMMERS

2020 ◽  
Vol 20 (1) ◽  
pp. 29-35
Author(s):  
E Podyacheva ◽  
T Zemlianukhina ◽  
E Simanovsky ◽  
E Fedorova ◽  
T Baranova

Aim. The article deals with studying the systemic protective mechanisms of the brain against hypoxia during water immersion in highly skilled swimmers. Material and methods. 25 males aged 18–20 years were examined: 9 masters of sports, one master of sports of international class and 15 people not involved in sports. The study of cerebral blood flow was carried out by rheoencephalography (REG). REG was recorded at rest, when the face was immersed in water and during recovery. Examination was carried out 2 hours after the morning training session. In addition to cerebral blood flow, ECG and blood pressure were recorded at rest, during water immersion and recovery. Statistical data processing was performed using nonparametric Mann–Whitney and Wilcoxon criteria. Results. It was revealed that athletes at rest demonstrated more pronounced asymmetry of blood circulation and higher blood flow in the right hemisphere than people not involved in sports. However, during water immersion, the asymmetry disappears, blood flow improves, especially in the left hemisphere in the carotid artery territory as a result of a decrease in the tone of small vessels. In people not involved in sports, protective mechanisms are less pronounced. Conclusion. Vast experience in sports activities related to exercises performed in water and to training hypoxic exercises contributed to effective protective mechanisms against hypoxia based on the diving reflex.

Author(s):  
Ashish Desai

In a previous study with dextral males, Richardson and Bowers (1999) digitized real time video signals and found movement asymmetries over the left lower face for emotional, but not non-emotional expressions. These findings correspond to observations, based on subjective ratings of static pictures, that the left side of the face is more intensely expressive than the right (Sackeim, 1978). From a neuropsychological perspective, one possible interpretation of these findings is that emotional priming of the right hemisphere of the brain results in more muscular activity over the contralateral left than ipsilateral right side of the lower face. The purpose of the present study was to use computer-imaging methodology to determine whether there were gender differences in movement asymmetries across the face. We hypothesized that females would show less evidence of facial movement asymmetries during the expression of emotion. This hypothesis was based on findings of gender differences in the degree to which specific cognitive functions may be lateralized in the brain (i.e., females less lateralized than males). Forty-eight normal dextral college students (25 females, 23 males) were videotaped while they displayed voluntary emotional expressions. A quantitative measure of movement change (called entropy) was computed by subtracting the values of corresponding pixel intensities between adjacent frames and summing their differences. The upper and lower hemiface regions were examined separately due to differences in the cortical enervation of facial muscles in the upper (bilateral) versus lower face (contralateral). Repeated measures ANOVA’s were used to analyze for the amount of overall facial movement and for facial asymmetries. Certain emotions were associated with significantly greater overall facial movement than others (p < .0001), beginning with surprise and followed by happy > fear > (angry = sad) > neutral. Both males and females showed this same pattern, with no gender differences in the total amount of facial movement under voluntary conditions. In males, movement asymmetries favoring the lower left side of the face occurred for most emotional expressions. For females, all emotions were symmetric over the lower face. Our findings with computer digitizing techniques support the hypothesis that there are gender differences in facial movement asymmetries during the expression of emotion. They further underscore the view that emotional processing may represent a more widely distributed system throughout the brain in women than in men, corresponding to previous reports that language processes are also less lateralized in women.


2018 ◽  
Vol 20 (3) ◽  
pp. 128-132
Author(s):  
V N Sysoev ◽  
A V Chebykina ◽  
M A Dushkina ◽  
V B Dergachev

Based on the analysis of the changes in the bioelectrical activity of the brain, the dynamics of cerebral blood flow and the vegetative balance of the body, the efficacy of a single 15-minute session of audiovisual stimulation for the correction of the functional state of the organism was evaluated. It was found that after the audiovisual stimulation session, the mean value of the alpha-rhythm power in the frontal, anterior-parietal and occipital leads of the right and left hemispheres of the brain was statistically significant more than in the background study. Such a change in the power of the alpha-rhythm reflects the level of ascending activation necessary for the organization of adaptive behavior, and can also characterize the intensity of the neuro-emotional stress. Increasing the power of the α-rhythm indicates a decrease in the level of nonspecific cerebral activation and is one of the main characteristics of the state of functional comfort. Statistically significant ifferences in the indices of powers of the β - and β -rhythms inherent in the state of active wakefulness were determined. The decrease1 2in the power index of the electoencephalography delta rhythm was revealed. The revealed dynamics of cerebral blood flow parameters was subject to pronounced individual differences, which made it impossible to determine the direction of the trend. It was established a gradual decrease in the power of the low-frequency component of the cardiorhythm with simultaneous increase in the contribution power of the high-frequency component, reaching a statistically significant difference at the last stage of registration, which leads to a significant decrease in the coefficient of vagosympathetic balance after the audiovisual stimulation session. The revealed changes indicate a decrease in the tone of the sympathetic part of the autonomic nervous system. Thus, it is established that after a single 15-minute audiovisual stimulation session, the value of the α-rhythm power in the frontal, anterior parietal and occipital leads of the right and left hemispheres of the brain increases, the power indices of the beta and delta rhythms of the electoencephalography decrease, the stress index and the vegetative index decrease balance, and also the coefficient of the vagosympathetic balance of the rhythmocardiogram. These changes characterize the optimization of the functional state of the organism and contribute to an accelerated restoration of working capacity.


1977 ◽  
Vol 47 (3) ◽  
pp. 346-352 ◽  
Author(s):  
Albert N. Martins ◽  
Thomas F. Doyle

✓ The exposed left superior frontal gyrus of the anesthetized macaque brain was focally traumatized by a jet of compressed air. Focal blood flow in tissue around the lesion and total cerebral blood flow was determined before and during the 4 hours after trauma by the hydrogen clearance technique. Blood flow fell in tissue adjacent to the injured brain but the reduction was not statistically significant. Total cerebral blood flow, blood flow in the right superior-frontal gyrus, and oxygen consumption of the brain was unaffected by the trauma. The authors conclude that neither spreading ischemia within uninjured tissue surrounding focally traumatized brain nor post-traumatic diaschisis is readily provoked in the anesthetized brain of the monkey.


1989 ◽  
Vol 28 (03) ◽  
pp. 88-91
Author(s):  
J. Schröder ◽  
H. Henningsen ◽  
H. Sauer ◽  
P. Georgi ◽  
K.-R. Wilhelm

18 psychopharmacologically treated patients (7 schizophrenics, 5 schizoaffectives, 6 depressives) were studied using 99mTc-HMPAO-SPECT of the brain. The regional cerebral blood flow was measured in three transversal sections (infra-/supraventricular, ventricular) within 6 regions of interest (ROI) respectively (one frontal, one parietal and one occipital in each hemisphere). Corresponding ROIs of the same section in each hemisphere were compared. In the schizophrenics there was a significantly reduced perfusion in the left frontal region of the infraventricular and ventricular section (p < 0.02) compared with the data of the depressives. The schizoaffectives took an intermediate place. Since the patients were treated with psychopharmaca, the result must be interpreted cautiously. However, our findings seem to be in accordance with post-mortem-, CT- and PET-studies presented in the literature. Our results suggest that 99mTc-HMPAO-SPECT may be helpful in finding cerebral abnormalities in endogenous psychoses.


2001 ◽  
Vol 14 (5) ◽  
pp. 407-415
Author(s):  
John T. Metz ◽  
Malcolm D. Cooper ◽  
Terry F. Brown ◽  
Leann H. Kinnunen ◽  
Declan J. Cooper

The process of discovering and developing new drugs is complicated. Neuroimaging methods can facilitate this process. An analysis of the conceptual bases and practical limitations of different neuroimaging modalities reveals that each technique can best address different kinds of questions. Radioligand studies are well suited to preclinical and Phase II questions when a compound is known or suspected to affect well-understood mechanisms; they are also useful in Phase IV to characterize effective agents. Cerebral blood flow studies can be extremely useful in evaluating the effects of a drug on psychological tasks (mostly in Phase IV). Glucose metabolism studies can answer the simplest questions about whether a compound affects the brain, where, and how much. Such studies are most useful in confirming central effects (preclinical and early clinical phases), in determining effective dose ranges (Phase II), and in comparing different drugs (Phase IV).


1994 ◽  
Vol 10 (4-5) ◽  
pp. 561-571
Author(s):  
Gunnar Heuser ◽  
Ismael Mena ◽  
Francisca Alamos

Exposures to neurotoxic chemicals such as pesticides, glues, solvents, etc. are known to induce neurologic and psychiatric symptomatology. We report on 41 patients 16 young patients (6 males, 10 females, age 34 8 yrs.) and 25 elderly patients (9 males, 16 females, age 55 7 yrs). Fifteen of them were exposed to pesticides, and 29 to solvents. They were studied with quantitative and qualitative analysis of regional cerebral bood flow (rCBF), performed with 30 mCi of Xe-133 by inhalation, followed by 30 mCi of Tc-HMPAO given intravenously. Imaging was performed with a brain dedicated system, distribution of rCBF was assessed with automatic ROI definition, and HMPAO was normalized to maximal pixel activity in the brain. Results of Xe rCBF are expressed as mean and S.D. in ml/min/100g, and HMPAO as mean and S.D. uptake per ROI, and compared with age-matched controls 10 young and 20 elderly individuals. Neurotoxics HMPAO Uptake Young Elderly R. Orbital frontal R. Dorsal frontal .70 .66 p < 0.05 R. Temporal .64 p < 0.001 R. Parietal .66 .66 We conclude that patients exposed to chemicals present with diminished CBF, worse in the right hemisphere, with random presentation of areas of hypoperfusion, more prevalent in the dorsal frontal and parietal lobes. These findings are significantly different from observations in patients with chronic fatigue and depression, suggesting primary cortical effect, possibly due to a vasculitis process.


2009 ◽  
Vol 24 (5) ◽  
pp. 275-281 ◽  
Author(s):  
Teresa Rodriguez-Cano ◽  
Luis Beato-Fernandez ◽  
Inmaculada Garcia-Vilches ◽  
Ana Garcia-Vicente ◽  
Victor Poblete-Garcia ◽  
...  

AbstractObjectiveThe aim of the present study is to see if the changes in the regional cerebral blood flow (rCBF) experienced by restrictive anorexia nervosa (AR) and bulimia nervosa (BN) patients, following the exposure to their own body image, persist at follow-up.MethodsThree single photon emission computed tomography (SPECT) were performed on nine patients with a DSM-IV diagnosis of AR, 13 with BP, and 12 controls: at rest, following a neutral stimulus, and after exposure to their previously filmed whole body image. Body dissatisfaction was measured by means of the Body Dissatisfaction Questionnaire (BSQ). One year later the same assessment was repeated.ResultsFollowing the exposure to their own body image, BN showed an increase in body dissatisfaction, which was associated with the increase in the rCBF of the Right Temporal Area. Those changes persisted at follow-up.DiscussionMore specific long term therapies are needed for the treatment of the averse response showed by ED patients to their own body image exposure that is associated with the hyperactivation of the right temporal area when they are confronted with their whole body image.


1992 ◽  
Vol 12 (2) ◽  
pp. 230-237 ◽  
Author(s):  
Marleen J. Verhaegen ◽  
Michael M. Todd ◽  
David S. Warner ◽  
Bruce James ◽  
Julie B. Weeks

Cerebral blood flow was measured by the H2 clearance method 30 and 60 min after the implantation of 300, 250, 125, or 50 μm diameter platinum–iridium electrodes 2 mm deep into the right parietal cortex of normothermic, normocarbic halothane-anesthetized rats. Another group of animals had 50 μm electrodes inserted 1 mm. In all animals, the presence or absence of a wave of spreading depression (SD) was noted at the time of implantation, with recordings made with glass micropipettes. H2 flow values were compared with those measured in gray matter from the same anatomical region (but from different rats), using [3H]nicotine. The incidence of SD ranged from 60% following insertion of 300 μm electrodes to 0% with 50 μm electrodes. H2 clearance flows also varied with electrode size, from 77 ± 21 ml 100 g−1 min−1 (mean ± standard deviation) with 300 μm electrodes to 110 ± 31 and 111 ± 16 ml 100 g−1 min−1 with 125 and 50 μm electrodes, respectively (insertion depth of 2 mm). A CBF value of 155 ± 60 ml 100 g−1 min−1 was obtained with 50 μm electrodes inserted only 1 mm. Cortical gray matter blood flow measured with [3H]nicotine was 154 ± 35 ml 100 g−1 min−1. When the role of SD in subsequent flow measurements was examined, there was a gradual increase in CBF between 30 and 60 min after electrode insertion in those animals with SD, while no such change was seen in rats without SD. These results indicate that the choice of electrode size and implantation depth influences the measurement of CBF by H2 clearance. CBF values equivalent to those obtained with isotopic techniques can be acutely obtained with small (50 μm diameter) electrodes inserted 1 mm into the cortex. While the occurrence of SD does influence CBF in the period immediately after implantation, a relationship between electrode size and measured flow is present that is independent of SD.


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