Effects of olfactory stimuli on students with different tones of the autonomic nervous system

The effect of olfactory stimuli was determined on students (men and women) with different tones of the autonomic nervous system under moderate psychoemotional stress conditions (before an academic test). It was found that the direction of changes in the heart rate variability values of students after olfactory stimulation is determined by the initial tone of the autonomic nervous system. The conclusion was made that olfactory stimuli may be used for correcting psychoemotional stress in students more efficiently if the tone of the autonomic nervous system is taken into consideration.     

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.     

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.     

Peculiarities of the Heart Rate Control during Competitive Entrance Examinations

A study was made of the dynamics of psychophysiological parameters and the activities of the systems regulating the heart rate in prospective post-secondary students taking competitive entrance examinations. The responses of the regulatory systems to examination stress were of two types, sympathetic and parasympathetic, depending on the initial state of the autonomic nervous system and the psychophysiological personality traits.     

Average magnitude of heartbeat fluctuations in healthy subjects after exposure to 4 hours head down bed rest

Orthostatic intolerance, induced by microgravity exposure, has been hypothesized to be related to a disorder of the autonomic control of the cardiovascular system. Non-invasive measurement of Heart Rate Variability (HRV) have been used as a valuable tool to characterize the ability of the autonomic system to modulate the cardiovascular function by analyzing the spontaneous fluctuations of arterial pressure and heart period on a beat-to-beat basis. Concerning this, conflicting results have been reported on the heart rate and blood pressure variability responses during exposure to microG. These differences seem to be due to different experimental designes used. Moreover, the different behavior of normal subjects in response to orthostatic stress after HD, i.e. Symptomatic (S) or Non Symptomatic (NS), could play some role in producing these discrepancies [correction of dicrepancies]. In this study we suggest the analysis of "magnitude" or "volatility" as a new method to study HRV variability. The volatility is a measure of the beat-to-beat excursion capability of the heart, regardless to its direction (positive or negative): the higher the volatility, the greater the excursion. The aim of the present study was to examine R-R volatility before and after 4 hours of HD -6 degrees in normal subjects.     

Psychophysiological mechanisms of stress in subjects with different representation of activation

The EEG spectral power was calculated in 102 students aged 18-25 years in three experimental conditions (during the common educational process, immediately before and after an examination). Before the examination (stress situation), predominant activation of the right anterior cortical quadrant (the area related with negative emotions, according to R. Davidson, 1993) was revealed by the asymmetry coefficient of the beta rhythm. Subjects with low amplitude of the alpha rhythm (more activated) manifested not only emotional but also autonomic disturbances, while only emotional signs were pronounced in students with high alpha (less activated). Increase in the theta rhythm spectral power during stress and its decrease in the poststress period were observed in the less activated persons, which is considered to be a normal reaction to emotionally negative stimuli. On the contrary, in students with low alpha the theta rhythm power in the stress situation was decreased pointing to their emotional instability. In this group, as distinct from the first one, the beta 2 rhythm recorded in the right anterior cortical quadrant did not decrease in the poststress situation. Together with the observed theta rhythm, decrease in the left-hemisphere and bilateral prefrontal areas in the stress situation, this deviation testifies to a predisposition to the reactive depression of these subjects.     

Changes in parameters of tachography and heart rate variability in students differing in the level of psychoemotional stress and type of temperament during an academic test week

Female students were examined to evaluate the effect of a test week on the parameters of tachography and heart rate variability depending on their initial psychoemotional stress level and type of temperament. A test week was shown to be a rather weak stressor, which virtually did not affect the psychological status of the students. However, their autonomic status clearly changed during the test week. This was caused by activation of the sympathetic autonomic system and was observed in both the students with a favorable psychoemotional state and choleric and sanguine subjects.     

The electrophysiologycal and information aspects of stress development

In the first part of this paper the modern concepts of stress and possibility of diagnostics of early stress manifestations are considered. Though significant advances of researches of this problem many methodological and methodical aspects are continued to be discussed. The categorical proff are stage development of adaptation processes and there classification [H. Selye]. A long-term studies of adaptation processes of students in semesters and exams have been conducted by authors with specially development and to accumulate new data. The second part of this paper is the survey of these results published in different time. The polyparametric technology including some electrophysiological methods with the system analysis using artificial intelligence algorithms and methods of pattern recognition permitted to show some regular dependences in relationships of electrophysiological parameters and there variations under stress development. It was shown for diagnostics of stress stages in necessary to assess not only absolute values of parameters but also there relationships, which are new diagnostics signs considering as information connections between physiological systems. The main characteristic of functional state of an organism is balance of parameter's relationships in totality, representing invariant for healthy persons. In condition of disharmony of parameter relationships there are aroused the strain, overstrain functional state or failure of adaptation in depends on a degree of misbalance. The represented new data don't contradict to known reasons and mechanisms of stress and accumulated data of its variety manifestations. As the work-hypothesis the information-wave model of appearance of psychosomatic reactions of stress is introduced.     

Noninvasive approach for study of human reaction and transferring velocity of nervous system by using a new instrumentation devised for concurrent microscopic observation and analysis of sweat secretion on human body under 1G and microgravity

Human sweating is generally caused by thermal and mental stimuli. The former role is well known as a response for thermo regulation. The insensible perspiration may be generally controlled by the autonomic nervous system, and the responses due to mental and/or emotional stress by the sympathetic nervous system. As human sweating is directly concerned with some nervous systems, sweating may be a good indicator for the body reactions of feeling, surprise, emotional stress and etc. The measuring of sweat secretion and microscopic observation of active sweat glands can be presented the direct information of working of sympathetic nervous system and sudomotor. In the present report, we devised an instrumentation for the estimation of time lag of sweating [correction of seating] after physical stimuli. Variation of gravity during parabolic flights is a kind of physical stimulus. Iwase et al reported the changes of sympathetic outflow to muscle in humans during short periods of microgravity. We studied also the variation of number of active sweat glands under this condition for the evaluation of human sympathetic nervous system.     

Cardiac autonomic balance in small-for-gestational-age neonates

The cardiac sympathetic nervous system is one putative key factor involved in the intrauterine programming of adult cardiovascular disease. We therefore analyzed cardiac autonomic system activity in small for gestational age (SGA) neonates. Heart rate variability (HRV) from 24-h ECG recordings were analyzed for time-domain and frequency-domain parameters in 27 SGA neonates [median 261 (240-283) days of gestation] compared with 27 appropriate for gestational age (AGA) neonates [median 270 (239-293) days of gestation]. In addition, salivary alpha-amylase levels were analyzed during resting conditions and in response to a pain-induced stress event in 18 SGA [median 266 (240-292) days of gestation] and 34 AGA [median 271 (240-294) days of gestation] neonates. Overall HRV was not significantly different in SGA neonates compared with AGA neonates (SD of all valid NN intervals: P = 0.14; triangular index: P = 0.29), and the sympathovagal balance [low frequency (LF)/high frequency (HF)] was similar (P = 0.62). Parameters mostly influenced by sympathetic activity did not reveal significant differences: (SD of the average of valid NN intervals: P = 0.27; average of the hourly means of SDs of all NN intervals: P = 0.66, LF: P = 0.83) as well as vagal tone-influenced parameters were unaltered (average of the hourly square root of the mean of the sum of the squares of differences between adjacent NN intervals: P = 0.59; proportion of pairs of adjacent NN intervals differing by >50 ms: P = 0.93; HF: P = 0.82). Median resting levels for alpha-amylase were not significantly different in SGA neonates (P = 0.13), and a neonatal stress stimulus revealed similar stress response patterns (P = 0.29). HRV and salivary alpha-amylase levels as indicators of cardiac autonomic activity were not altered in SGA neonates compared with AGA neonates. Thus, it appears that the intrauterine activation of the sympathetic system in SGA fetuses does not directly persist into postnatal life, and neonatal sympathovagal balance appears to be preserved.     

The Galvanic Skin Response as a Reflection of the Decision-making Process under Conditions of Time Deficit

It is now difficult to find any studies in psychophysiology in which the galvanic skin response (GSR) is not recorded, but there is still no consensus concerning the functional significance of this reaction. The GSR reflects the degree of emotional tension [5], and is also one of the autonomic components of an orienting response [2].     

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.     

Influence of examination stress and psychoemotional characteristics on the blood pressure and heart rate regulation in female students

During the semester and immediately before an examination, changes in the heart rate variability, blood pressure, and state anxiety induced by examination stress, as well as the dependence of these changes on the probabilistic prediction and actual examination mark, were investigated. Before an examination, most students exhibited an increase in state anxiety, diastolic blood pressure, and heart rate; the last of these is connected with an increase in the LF/HF ratio. The behavior of the cardiovascular system of the students (who were females) under psychoemotional stress varied considerably depending on how well they were prepared for the examination and on the subjective prediction of success. The importance of the type of heart rate regulation during the semester for the progress of examination stress was established.     

Mouse strain differences in autonomic responses to stress

In humans, anxiety disorders are often accompanied by an overactive autonomic nervous system, reflected in increased body temperature (BT) and heart rate (HR). In rodents, comparable effects are found after exposure to stress. These autonomic parameters can give important information on stress and anxiety responses in mice. In the present experiments, stress reactivity of three frequently used mouse strains [129 Sv/Ev, Swiss Webster (SW) and C57 BL/6] was assessed using their autonomic stress responses. BT, HR and activity were telemetrically measured. Undisturbed circadian rhythms already showed clear differences between the mouse strains. Hereafter, autonomic responses to stressors with increasing intensity were measured. Strain differences were found in magnitude and duration of the stress responses, especially after high-intensity stressors. Generally, C57BL/6 mice showed the largest autonomic response, SW the lowest and the 129Sv/Ev the intermediate response. Interestingly, the observed ranking in autonomic stress response does not match the behavioral stress responsivity of these strains. Finally, sensitivity to the anxiolytic diazepam (0, 1, 2, 4 and 8 mg/kg) was tested using the stress-induced hyperthermia paradigm. Pharmacological sensitivity to diazepam differed between the strains with the 129Sv/Ev being most sensitive. These studies show that simultaneous measurement of behavioral and autonomic parameters under stressful conditions contributes considerably to a better interpretation of anxiety and stress levels in mice.     

Neural basis for unique hues

All colors can be described in terms of four non-reducible ‘unique’ hues: red, green, yellow, and blue [1]. These four hues are also the most common ‘focal’ colors — the best examples of color terms in language [2]. The significance of the unique hues has been recognized since at least the 14^th century [3] and is universal [4] and [5], although there is some individual variation [6] and [7]. Psychophysical linking hypotheses predict an explicit neural representation of unique hues at some stage of the visual system, but no such representation has been described [8]. The special status of the unique hues “remains one of the central mysteries of color science” [9]. Here we report that a population of recently identified cells in posterior inferior temporal cortex of macaque monkey contains an explicit representation of unique hues.     

Emotional Stress in Students during Examinations

The psychoemotional reactions of students caused by examinations were studied on the basis of a modern theory of emotions by means of a complex of modern psychophysiological methods. To study the role of probabilistic forecasting of results in the development of the psychoemotional state, each student was asked to predict his or her mark. Groups were formed based on the difference between the expectations and the actual mark. In general, examination-induced emotional stress in students was characterized by a complex of psychophysiological and autonomic changes depending on the probabilistic estimation of the mark, preparedness for the examination, and the result. The theoretic aspect of the study was related to the development of the concept of emotion genesis. The practical aspect included educational process optimization in order to improve the psychoemotional status of students.     

Reconstitution of amoeboid motility in vitro identifies a motor-independent mechanism for cell body retraction

Crawling movement in eukaryotic cells requires coordination of leading-edge protrusion with cell body retraction [1-3]. Protrusion is driven by actin polymerization along the leading edge [4]. The mechanism of retraction is less clear; myosin contractility may be involved in some cells [5] but is not essential in others [6-9]. In Ascaris sperm, protrusion and retraction are powered by the major sperm protein (MSP) motility system instead of the conventional actin apparatus [10, 11]. These cells lack motor proteins [12] and so are well suited to explore motor-independent mechanisms of retraction. We reconstituted protrusion and retraction simultaneously in MSP filament meshworks, called fibers, that assemble behind plasma membrane-derived vesicles. Retraction is triggered by depolymerization of complete filaments in the rear of the fiber [13]. The surviving filaments reorganize to maintain their packing density. By packing fewer filaments into a smaller volume, the depolymerizing network shrinks and thereby generates sufficient force to move an attached load. Our work provides direct evidence for motor-independent retraction in the reconstituted MSP motility system of nematode sperm. This mechanism could also apply to actin-based cells and may explain reports of cells that crawl even when their myosin activity is compromised.     

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.     

Expression partitioning between genes duplicated by polyploidy under abiotic stress and during organ development

Allopolyploidy has been a prominent mode of speciation and a recurrent process during plant evolution and has contributed greatly to the large number of duplicated genes in plant genomes [1-4]. Polyploidy often leads to changes in genome organization and gene expression [5-9]. The expression of genes that are duplicated by polyploidy (termed homeologs) can be partitioned between the duplicates so that one copy is expressed and functions only in some organs and the other copy is expressed only in other organs, indicative of subfunctionalization [10]. To determine how homeologous-gene expression patterns change during organ development and in response to abiotic stress conditions, we have examined expression of the alcohol dehydrogenase gene AdhA in allopolyploid cotton (Gossypium hirsutum). Expression ratios of the two homeologs vary considerably during the development of organs from seedlings and fruits. Abiotic stress treatments, including cold, dark, and water submersion, altered homeologous-gene expression. Most notably, only one copy is expressed in hypocotyls during a water-submersion treatment, and only the other copy is expressed during cold stress. These results imply that subfunctionalization of genes duplicated by polyploidy has occurred in response to abiotic stress conditions. Partitioning of duplicate gene expression in response to environmental stress may lead to duplicate gene retention during subsequent evolution.