Reactions of the autonomic nervous system of students with different characteristics of higher nervous activity in the situation of examination stress

The influence of examination stress on the reactions of the autonomic nervous system in students with different levels of functional mobility of nervous processes (FMNP) was studied. More intense functioning of the cardiovascular system and the strain of all regulatory mechanisms during examination stress were characteristic of individuals with low FMNP, whereas students with high FMNP values were characterized by a weaker strain of the mechanisms of cardiac rhythm regulation, more economical activity of the cardiovascular system, and better performance on the examinations. The activation of humoral, metabolic, and sympathetic effects was observed in all the subjects under examination stress, along with decreased parasympathetic effects on the cardiac rhythm.     

Systemic and cerebral hemodynamics and mental activity in marked neuro-emotional stress]

Changes in efficiency of mental activity and general and brain hemodynamics in students of physico-mathematical faculty when they solve problems on math analysis for 3 hours under conditions of pronounced neuro-emotional tension (NET) during examination have been experimentally studied. The results obtained from these studies are considered. It is shown that relation of higher nervous activity and general and brain hemodynamics is determined by efficiency of the activity, its energy provision (intensity), the level of NET and the rate of automated psychic reactions. A conclusion is made that efficiency of the activity is a basic system-forming factor in a relation arising between higher nervous activity, on the one hand, and general and brain hemodynamics, on the other hand. The higher is the efficiency, the lower are power requirements and the level of NET and the higher is the rate of automated psychic reactions: mental working capacity.     

The influence of examination stress on psychophysiological characteristics and heart rate in students

With the aim to assess the influence of pre-examination psychoemotional stress on the level of centralization of the heart rate control, mathematical analysis of ECG of students was performed in normal condition (a common day of academic semester), before, and after an examination. The ECG was recorded and processed with the help of IBM-486 PC. R-R cardiointevalograms were processed by the method of variational pulsometry after Baevsky. Common quantitative heart rate indices were studied. The level of anxiety of students was assessed by Spilberger, and subjective estimations of general condition, activity and mood were obtained from the respective questionnaire. Three types of heart rate reactions on the examination stress were revealed. The reactions depended on the individual typological characteristics and the state of autonomic nervous system.     

The level of anxiety and state of autonomic regulation depending on the predicted examination grades in students living under unfavorable environmental conditions

The examination situation evokes psychoemotional and autonomic reactions with different degrees of intensity depending on the predicted grades in first-year students living under unfavorable conditions of the middle Ob’ River basin. All the examined students (residents of the middle Ob’ River basin) were found to have a high or super high level of trait and state anxiety. The unfavorable emotional state was accompanied by different degrees of the strengthening of parasympathetic effects on cardiac activity and the tension of regulatory systems that were at a maximum in students who expected a C grade. Irrespective of the predicted result, the highest levels of anxiety and increase in the stress of regulatory systems were observed in female students.     

EEG Based Evaluation of Examination Stress and Test Anxiety Among College Students

BackgroundAdolescence is a crucial chapter in life and the presence of stress, depression, and anxiety at this stage is a great concern. Prolonged stress is one of the risk factors that may induce suicidal thoughts, destructive ideation, abuse of alcohol, and drugs in adulthood. Based on a record from National Crime Records Bureau, In India over 2320 children were committed suicide per year because of failure in examinations. This raised number implies the severity of this issue and its major impact on society.ObjectivesThe main objective of this paper is to analyze the cognitive stress in students during examination period using EEG biomarkers.Methods and ResultsEEG signal was acquired in two different test conditions such as before examination with 12 minutes and after examination with 3 minutes from 14 subjects with eight electrodes located using wireless Enobio device (Neuro electrics) with 10-20 international lead system. The three brain waves such as theta, alpha, beta relative band energies were considered, and EEG band ratios such as heart rate, neural activity, arousal index, vigilance index and cognitive performance attentional resource index extracted between before and after examination condition using db4 wavelet family with 6 level decomposition. The statistical results suggest that after examination the relative sub-band energies α, β, and θ were decreased significantly (p < 0.05) as compared to before examination. Also, the EEG band ratio such as heart rate and vigilance index shows significant (p < 0.05) decrease after the examination as compared to before examination. It was found that there was a significant (p < 0.05) rise in the arousal index, Cognitive performance attentional resource index (CPARI), and neural activity after the examination as compared to before examination.ConclusionThe experimental results found that the memory and concentration were high before examination, which concludes that adolescence group examination stress was high before examination period as compared to after examination. In the case of gender group comparison, theta energy band for male students was found high compared to female students in before examination state such that it concludes that male students were highly stressed (before examination) than female students. Overall, our results suggest that after examination male students with lower heart rate index than female students which implies the male students control their stress levels as compared to females in the same stress situation.     

The Neural Substrates of Self-Evaluation of Mental Fatigue: A Magnetoencephalography Study

There have been several studies of the neural mechanisms underlying sensation of fatigue. However, little is known about the neural mechanisms underlying self-evaluation of the level of fatigue. The aim of this study was to identify the neural substrates involved in self-evaluation of the level of mental fatigue. We used magnetoencephalography (MEG) with high temporal resolution on 14 healthy participants. During MEG recordings, participants were asked to evaluate their level of mental fatigue in time with execution cues (evaluation trials) or to do nothing in time with execution cues (control trials). The MEG data were analyzed with equivalent current dipole (ECD) and spatial filtering methods to localize the neural activity related to the evaluation of mental fatigue. The daily level of fatigue sensation was assessed using the Checklist Individual Strength questionnaire. In evaluation trials, ECDs were observed in the posterior cingulate cortex (PCC) in seven of 14 participants, with a mean latency of 366.0 ms. The proportion of the participants with ECDs in the PCC was higher in evaluation trials than in control trials (P<0.05, McNemar test). The extent of the decreased delta band power in the PCC (Brodmann’s area 31) 600–700 ms after the onset of the execution cue and that in the dorsolateral prefrontal cortex (DLPFC; Brodmann’s area 9) 800–900 ms after the onset of the execution cue were greater in the evaluation trials than in the control trials. The decrease in delta band power in the DLPFC was positively related to that in the PCC and to the daily level of fatigue sensation. These data suggest that the PCC and DLPFC are involved in the self-evaluation of mental fatigue.     

PBL教学模式在病原生物学、免疫学及感染病学课程整合改革中的探索与实践

探讨问题导向教学(PBL)方法在病原生物学、免疫学及感染病学课程整合改革中的教学效果及意义。以中国医科大学2009级七年制临床系学生240人为研究对象,随机分为实验组和对照组各120人。实验组采用PBL教学方法,教学内容采用病原生物学、免疫学及感染病学整合,对照组采用传统教学方法,教学内容为传统病原生物学课程,2组由相同教师授课,采用期末考试和教学效果自评调查问卷的方式评价教学效果。实验组与对照组相比,期末考试成绩无统计学差异(P>0.05),但病例分析题成绩有统计学差异(P<0.01)。2种学生的自评调查问卷中,实验组的自学能力、团队协作能力及发现问题解决问题的能力均显著高于对照组(P均<0.01)。PBL教学模式能有效提高教学质量,具有一定的示范及推广价值。     

EEG correlates of individual differences in performance efficiency of students during examination stress

Performance of cognitive tests and EEG spectral power were evaluated in 39 students aged from 19-21 years in two conditions: during common educational process and immediately before examination (stress condition). Before examination, the performance was better in subjects with low level of spectral density in the delta band (in the occipital, parietal, central and frontal cortical areas) and high level of the alpha-rhythm spectral density in all the cortical areas, A decrease in performance scores before examination was correlated with an increase in the delta activity (in the right frontal and temporal cortical areas) and rise of the anxiety level (tested by Spielberger).     

Free-radical processes and the antioxidant system in the realization of the recovery function of sleep

The somnological status of test subjects was assessed. The content of malonic dialdehyde, total peroxidase activity, and concentration of uric acid, urea, and total protein in the saliva of students with insomnia and age-matched (20- to 23-year-old) healthy students were determined during everyday studies and summer exams. It was found that emotional (examination) stress intensifies free-radical processes and leads to a compensatory increase in the activity of the nonenzymatic antioxidant system in the saliva of students. Insomnia is accompanied by an increased level of free-radical processes and increased total protein content in the saliva of test subjects. The recovery anabolic function of sleep is realized via activation of protein synthesis and involvement of low-molecular-weight nonenzymatic antioxidant compounds (uric acid and urea) in the defensive responses of the body under conditions of a significant increase in the intensity of free-radical processes during examination stress combined with insomnia.     

Relation between the level of conditioned reflex activity and concentration of serotonin in the blood of normal and neurotic dogs

Higher nervous activity of dogs was studied using Pavlovian method of alimentary salivary conditioned reflexes. Serotonin (5- hydroxytryptamine) content in the venous blood was defined by means of fluorescent spectrofluorimeter using orthophthalic dialdehyde. A high level of conditioned and unconditioned reflexes was accompanied by a low serotonin blood content, while a low level of reflexes was accompanied by a high serotonin content. Negative correlation is supposed to exist between the degree of activation of nervous processes and blood serotonin content. Blood serotonin content increased in dogs in experimental neurosis with expressed reduction of the level on alimentary conditioned and unconditioned reflexes.     

Irreversible modification of measles virus RNA in vitro by nuclear RNA-unwinding activity in human neuroblastoma cells.

The matrix (M) gene of a measles virus (MV) variant passaged in IMR-32 human neuroblastoma cells displays numerous uridine-to-cytosine transitions called biased hypermutation. Using an in vitro assay, we show that IMR-32 cells contain high levels of an activity which unwinds and irreversibly alters the base pairing of double-stranded RNA synthesized from the M gene of MV. This activity is found exclusively in the cellular nucleus and is present at a lower level in African green monkey kidney Vero cells. Experiments with mixed cell extracts suggest that the low activity in Vero cells is not due to inhibitory factors. These findings support the hypothesis that this RNA-modifying and -unwinding activity is responsible for biased hypermutation of MV strains that infect the central nervous system. Possible functions of this neural cell activity and implications for central nervous system disorders are discussed.     

Electron microscopic-cytochemical study of succinate dehydrogenase activity of nerve tissue cells of human embryos in vitro

The ultrastructural localization of succinate dehydrogenase (SDH) activity was revealed in astrocyte-like cells of 26 days old nervous tissue organotypic cultures. The Kerpel-Fronius and Hajos (1968) technique was employed using potassium ferricyanide as an artificial acceptor of electrons. The localization of the reaction product was seen more often in cells with long, thread-like mitochondria. The appearance of such organelles with a large membrane length and high enzymatic activity is suggested to reflect one of the mechanisms of adaptation of nervous tissue cells providing the adequate level of the energy supply under in vitro conditions.     

The effects of the level of physical activity on calcaneal ultrasound measurements: bone properties of medical and physical education students

The aim of the study was to compare bone properties of two groups of students which strongly differ in the level of their everyday physical activity; the School of Medicine (SM) students and the Faculty of Physical Education (FPE) students, University of Zagreb. Quantitative ultrasound parameters--broadband ultrasound attenuation (BUA) and speed of sound (SOS) were measured. Quantitative ultrasound index (QUI) and estimated bone mineral density (BMD) were calculated by the device software. The final study sample consisted of 165 students from SM (94 males and 71 females) and 215 students from the FPE (164 males, 51 females). Sixty eight percent of FPE students and 21% of SM students reported a high level of everyday physical activity (P < 0.001). All ultrasound parameters were significantly higher in FPE students than in SM students (at the P < 0.001 level). The multiple regression model of the QUI confirmed that the school students attended was the single significant predictor variable for both genders. Our data indirectly showed the beneficial role of physical activity on bone properties.     

The psychophysiological condition of first year students with different levels of physical activity

The psychophysiological condition of (male) first year students who participate in sport or don't participate in sport during studies was studied. R. M. Bayevsky's method was used to establish the level of stress on regulatory mechanisms. The functional level of the nervous system, stability of neural responses, and the level of functional abilities of the developed functional system were evaluated using the variation chronoreflexometric method. It was established that an improvement of mental capacity indicators (increase of memory capacity, reduction of the amount of mistakes made, growth of the level of functional abilities and reduction of the latency period of the visual-motor response) was accompanied by a growth of stress on the body's regulatory systems which was more pronounced with regard to those test participants whose level of physical activity was low. This fact is proof that physical activity reduces the body's "adaptation price" to the changing conditions of the environment. The optimal realisation of a person's adaptive systemic reactions is provided for by the dynamic interaction of the functional systems, which form a complex correlation in the body's somatovegetative, motor and psychoemotional spheres of activity.     

Changes in levels of translatable mRNA for neuron-specific enolase and non-neuronal enolase during development of rat brain and liver

Neuron-specific enolase (NSE), and non-neuronal enolase (NNE) which exists in many tissues including liver but is localized in glial cells within the nervous system, were synthesized in the rabbit reticulocyte cell-free translation system programmed with brain mRNAs. The in vitro synthesized NSE and NNE were indistinguishable from the two enzymes purified from rat brains. NSE mRNA activity was found only in brain RNAs, while NNE mRNA activity existed in brain RNAs as well as liver RNAs. In developing brains, the level of translatable NSE mRNA was low at the embryonic stage and at birth, increased rapidly from about 10 days postnatal, and reached the adult level, while that of NNE mRNA was high at the embryonic stage and at birth, followed by a slight decrease then a gradual rise to adult levels. These changes correlated with the developmentally regulated appearance and accumulation pattern of each of the two enzymes. These results suggest that the levels of NSE and NNE are controlled primarily by the level of each of the two translatable mRNAs. In developing livers, only the NNE mRNA activity was detected and its level generally paralleled the changes in the level of NNE.     

Cerebellum and organization of behavior: A comparative-physiological aspect

The ontophylogenetic analysis of morphofunctional peculiarities of the cerebellum shows its extremely high adaptability to the requirements for the organization of the nervous activity of the organism corresponding to the level of its evolutionary development and ecological habitat conditions. The changes of the cerebellum in the course of its onto- and phylogenetic development appear to be more pronounced as compared with other cerebral regions. Depending on the level of the development, revealed are different aspects of the cerebellar integrative activity which contributed, if necessary, a quite new directions of the nervous activity, such as learning and cognition, which demonstrates astonishingly wide limits of the adaptability. This explains that the cerebellum in various vertebrates is considerably different by its shape, location of neurons in the cerebellar cortex, and the main peculiarities of afferent, internal, and efferent pathways. There is a reason to suggest that the future study of these aspects of the cerebellar activity will bring us to a clearer understanding of the cerebellar mechanisms of learning.     

Music Attenuated a Decrease in Parasympathetic Nervous System Activity after Exercise

Music and exercise can both affect autonomic nervous system activity. However, the effects of the combination of music and exercise on autonomic activity are poorly understood. Additionally, it remains unknown whether music affects post-exercise orthostatic tolerance. The aim of this study was to evaluate the effects of music on autonomic nervous system activity in orthostatic tolerance after exercise. Twenty-six healthy graduate students participated in four sessions in a random order on four separate days: a sedentary session, a music session, a bicycling session, and a bicycling with music session. Participants were asked to listen to their favorite music and to exercise on a cycle ergometer. We evaluated autonomic nervous system activity before and after each session using frequency analysis of heart rate variability. High frequency power, an index of parasympathetic nervous system activity, was significantly increased in the music session. Heart rate was increased, and high frequency power was decreased, in the bicycling session. There was no significant difference in high frequency power before and after the bicycling with music session, although heart rate was significantly increased. Additionally, both music and exercise did not significantly affect heart rate, systolic blood pressure or also heart rate variability indices in the orthostatic test. These data suggest that music increased parasympathetic activity and attenuated the exercise-induced decrease in parasympathetic activity without altering the orthostatic tolerance after exercise. Therefore, music may be an effective approach for improving post-exercise parasympathetic reactivation, resulting in a faster recovery and a reduction in cardiac stress after exercise.     

Individual specificity of the autonomic support of purposive activity in students performing computer-aided tests

The autonomic correlates of individual differences in the effectiveness of purposive activity during a computer-aided sensorimotor test and computer-aided testing of the level of knowledge of students were studied. Students who reached high results of sensorimotor and academic tests were characterized by lability of autonomic indices, which manifests itself in a change in the absolute values and relationship of the characteristics of heart rate and hemodynamics in accordance with activity stages. These changes were specific for each form of activity and were connected with the results of the tests. The physiological prerequisites of the high lability of autonomic characteristics which ensures the ability of the subject to successfully adapt to the conditions of the activity included high initial values of TP and power of LF- and HF-ranges of heart rate variability at a LF/HF ratio close to unity, reflecting a high level of balanced sympathetic and parasympathetic effects on cardiovascular functions.     

Development of examination stress in subjects with various levels of cortical activation

The work is aimed at the study of neurophysiological mechanisms of examination stress in subjects with different levels of cortical activation. Spectral power and typical cortical connections of EEG rhythms were studied in students under conditions of stress before and immediately after examination as well as during usual academic semester. Students with relatively higher and relatively lower baseline alpha rhythm, i.e., with different levels of cortical activation revealed both similar and different EEG reactions. Before examination, in both groups of subjects the spectral power of EEG activity in the delta and thetal bands increased, and the number of connections in the bands of the alpha and beta 1 rhythms decreased as compared to usual baseline conditions. However, the EEG reactions in the theta 2 band in the two groups were oppositely directed. Significant changes in the beta 2 power were observed only in the group of subjects with higher baseline level of cortical activation.     

Ca(2+)-ATPase and Mg(2+)-ATPase in Aplysia glial and interstitial cells: an EM cytochemical study.

The localization of Ca(2+)- and Mg(2+)-ATPases was determined in Aplysia central and peripheral nervous system, using an electron microscopic cytochemical method. The enzyme activity appeared localized to the membrane of glial granules (gliagrana), particularly in the peripheral nervous system of the esophagus, and on the plasma membrane of central glial cells adjacent to neuronal cell bodies. No calcium- and/or magnesium-ATPase activity was detectable on the plasma membrane of glial cells surrounding nerve axons in the pleuro-visceral connectives. These findings are discussed along two main lines: (a) the calcium-ATPase of the gliagrana coincides with a high intragranular calcium and/or proton concentration; and (b) the presence of a calcium-ATPase activity at the glio-neuronal interface around the neuronal cell bodies coincides with the use of calcium ions as charge carriers of the action potential, and its absence at the level of the axon with the concurrent functional use of sodium ions.