M.P. Chernisheva

Summary: Complex of time processes (TP) is a component of the organism time structure and comprises basis of its endogenous time. Asymmetrical TP are represented by the 'arrow of time' of ontogenesis with the past, present, and future times that have different properties as well as by tendencies and monophasic processes. Rhythms and cycles are ascribed to symmetrical TP. They maintain optimum of the organism energetic potential. Disturbances of the rhythms or cycles lead to acceleration of aging. Regulation of life duration in correspondence with program of genome can be realized by a change of correlation between symmetrical and asymmetrical TP in the organism time structure as well as through a strengthening of asymmetry of the asymmetric TP.

Keywords: biological time and temporal processes, properties of asymmetric and symmetric time processes, regulation of endogenous time.

 

The issue of asymmetry of time has been traditionally considered in connection with its orientation from the past through the present into future (Strakhov, 2007; Callender, 2002; et al.) and cause-and-effect interrelations between events (Kozyrev, 1989; Korotaev, 2006, et al.). The organism endogenous time is represented by the whole complex of time processes that have properties of symmetry or asymmetry. Properties and functions of the time processes as components of the organism time structures have been poorly studied.

 

1. Time and time processes

According to Isaac Newton, time processes are referents of Time; but are the Time and the time processes identical? In terms of the substantial hypothesis of the nature of time (Kozyrev, 1989; Levich, 2000, 2006; et al.), it can be suggested that the substantial flow of Time that has energy (Korotaev, 2006) penetrates all levels of the being and triggers at each of them the time processes that have several properties that are both similar with and different from time. In living organisms, intensifiers of effects of Time and mediators of such initiation of time processes can be endogenous generators of the organism time structure (cellular oscillators, tissue pacemakers, timers of physiological systems)*. This suggestion is confirmed by several common properties in Time and in time processes: orientation and continuity.

Besides, the time processes have properties differing from Time: latency, duration, sequence, irregularity of the rate and density. The assembly of the organism time processes represents its endogenous (internal or biological) time that has the informational-energetic nature (Chernisheva, Nozdrachev, 2006)**. This agrees with the concept of information as negentropy (Brullien, 2006) and energy (Swaab, 2006; et al.) as well as with participation of time in encoding of information in the nervous system (Radchenko, 2002; Jakubs et al., 2006; Karmakar, Buonomano, 2007; et al.).

 

 

____________¹ Time processes, their generators, and mechanisms of subjective time correcting endogenous time relative to the exogenous one are components of the organism time structure (Chernisheva, Nozdrachev, 2006).

 

 

1.1. Types of time processes

Described in living organisms are such types of time processes as 'arrow of time' of ontogenesis (the directed time) and superposed monophasic processes, tendencies, cycles, and rhythms. These time processes have different functions and properties. Monophasic processes mark the beginning and/or end of a certain period of ontogenesis (for instance, birth, maturation, climax, etc.). The tendencies support certain monotonously changing parameter (the mean level of arterial pressure, concentration of sexual steroid hormones, etc.) within the limits peculiar to this period. The number of cycles can determine duration of the period. For instance, the number of estral cycles in ovaries determines duration of reproductive period and is a species-specific character in mammals (McCraken et al., 1999). Rhythms promote structurization of exo- and endogenous information, flows of energy, and decrease dispersion of values of certain parameters (body temperature, enzyme activities, blood Са⁺² content, etc.). Thereby, rhythms decrease manifestation of chaos, increase the coefficient of order h, and, hence, decrease maximally the rise of the generalized entropy (Chernisheva, Nozdrachev, 2006). It is obvious that the described types of time processes at the level of molecule, cell, tissue, physiological system, and organism are principally similar, but can have different manifestations.

Some concept about symmetry (resemblance) and asymmetry (disturbance of resemblance) (Darvac, 2001) is applicable to various types of time processes. Cycles and rhythms have property of symmetry in this aspect. Ascribed to asymmetrical can be the directed ontogenesis time that includes the past, present, and future times as well as monophasic processes and tendencies.

 

 

² The Aristotle's thesis 'time is a measure of movement (measure of change)' as applied to living organisms can be formulated as 'time is a measure of a change of information'. Information about actions of various energetic natures on the organism appears in specific sensory structures (receptors). Its primary code in the nervous system is sequence of nervous impulses and has the electro-chemo-time nature. This implies coupling of time with energy and information. Hence, time can be expressed through:

Т= (E_inf + E_d)/m,

where E_inf - energy of processing of information, E_d - energy dissipating into the thermal one, m - instant intensity of metabolism (cal/s or kJ/s).

 

 

1.1.1. Asymmetric time processes

Asymmetry of time has long being discussed among philosophers and mathematicians (Strakhov, 2006; Сallender, 2002, et al.). In terms of geometrical model of time, polar opinions about the present were expressed: either it does not exist (a 'dot' on the axis of time) or it is measureless and includes the past and the future. The current concepts about time processes at the levels of cells, tissues, and physiological systems of living organisms allow a revised point of view on this problem and concretization of difference of properties and functions of the past, present and future (Chernisheva, Nozdrachev, 2006). First of all, let us notice their difference in the volume of information, level of energy, and the rate of rise of entropy, which are maximal for the present and minimal for the future.³

To properties of the present time can also be ascribed: the novelty (change) of information. The novelty acts as a 'reference point' or the beginning of the present. This allows differentiation of information coupled with the present, past or future as well as detection and estimation of the degree of the novelty through its comparison with the information that is already stored in memory from the past. Besides, properties of the present can be thought to involve estimation of dynamics of the information flow and organization of information during its processing and entrance to memory. Combination of these processes can determine the total duration of the present. Since separately they have different duration, the end of the present is blurred, unlike its reference point.

About properties of the past time interconnected with memory mechanisms, it is possible to identify the absence of information novelty: memory stores the already known, processed information, and the absence of time scanning for information about the past events (prior to initiation of the recollection mechanism).

 

-^-3 It is to be noted that it is for the continuing present time that Boltzmann's idea about evolution of time in the direction of rise of entropy is true. For phylogenesis, an increase of metabolic intensity according to Le Châtelier's principle is coupled with a rise of entropy. Hence, an increase of the information value (as negentropy) perceived by living organisms can be considered to be a compensatory mechanism.

 

The future time is characterized by the following properties: motivation and purpose play role of factors of temporal organization of information about future; projectivity and schematicity; the concrete subjective information about future is discrete: it includes only goal and the initial stages of its achievement; information about future includes evaluation of the time of achievement of the goal as a separate 'block of information'; program of future time is formed in the presence with participation of the information stored in memory, i.e., information of the past time. At the same time, memory can store a number of non-realized programs of future, which were formed in the past. These differences of properties of the past, present, and future times do not allow suggesting mirror symmetry of the past and future relative to the present, as believed by some philosophers, as well as instantaneousness of the present time [9], at any rate, for living organisms.

 

Meanwhile, it cannot help noting contradiction of asymmetry of the 'arrow of time'. Thus, although the past is not identical (asymmetrical) to the future and both of them are not identical to the present, the past holds unrealized variants of the future. Further, in the present the information of the present (the new one) and that of the past are combined for formation of a new program of the future, e.g., the past and the present are included into the future, while the future - into the present and the past. Besides, the greater instability, the levels of energy and entropy of time processes of the present time, which are connected with processing of new information, make it an energy donor for maintenance of the informational fullness of the past time and for the 'structuring' of the future time - this is the functional meaning of combination of the past and future times.

1.1.2. Symmetrical time processes

 

By definition, rhythms and cycles can be ascribed to symmetrical time processes: these processes themselves are identical at their repetitions. The rhythms limit dispersion of various organism parameters prone to synchronization and thereby organize flows of energy and information, which provides the level of chaos and a rise of generalized entropy. Therefore the rhythm can be considered as a mechanism of a decrease of the rise of entropy. This corresponds to the concept of circadian and seasonal rhythms as a mechanism of leading homeostatic information, which is directed at realization of adaptive strategy of metabolism and at saving of energy (Alpatov, 2000, et al.). Hence, it can be suggested that the necessity for fine adjustment to the exogenous rhythm (for instance, to the illumination rhythm) in the organism arises in the case of energy misbalance and insufficiency of endogenous mechanisms decreasing the level of generalized entropy. Then the external 'pacemakers' of rhythm play a role of the energy donor and of the protector of an increase of the generalized entropy. Owing to this, the rhythms maintain (probably to the greater degree than other time processes) values of the organism homeostatic constants (body temperature, volume of memory and perceived information, blood sugar content, etc.) within the limits of the optimum assigned by the geno- and phenotype.

Besides, synchronization of rhythms as of symmetrical time processes seems to promote accumulation of energy. This is indicated by the cardiorespiratory synchronism described in muscular loadings under conditions of an increase of the muscle oxygen debt (Pokrovsky et al., 2002). It is aimed at enhancement of tissue respiration, i.e., homeostasis of the organism energy potential. It has been shown that in hypothalamus [1] and neocortex [3,10, et al.], synchronization of rhythms corresponding to impulse activity of neurons and electroencephalogram is used as a mechanism of enhancement and separation from the noise of a signal and/or a response to action. Synchronization and an increase of amplitude of visceral rhythms at initiation of stress-response also serve a rise of the level of the organism energy potential.

Cycles as symmetrical time processes are represented by repeated cycles of cell division (mitosis), respiratory and cardiac cycles, estral cycle, metabolic cycles, etc., which are identical to themselves. At the same time, in frames of each rhythm, it is possible to notice elements of asymmetry expressed through parameters of a time process: a different duration of phases (inspiration and expiration, heart systole and diastole, etc.) or frequency of cycles during the day and night, at different stages of sleep, etc. Reiteration and stereotypy of reactions of a certain cycle as well as of its total duration indicate the lower expenditures of energy and time, a minimum of the rise of entropy as compared with asymmetrical time processes.

Since the state of homeostasis corresponds to the 'norm of chaos' of the open unstable thermodynamic biosystem characterized by the minimal rise of the entropy level and a possibility of reversible processes (Klimontovich, 1996), it is possible to admit the relative reversibility of symmetric time processes (but not of time) during homeostasis in the frames of optimum of the norm of reaction of the organism phenotype.

 

2. Time processes and codes of time

One of the most mysterious functions of time processes is their role in encoding of intervals of the current time (the presence) and duration of ontogenesis (life) of individual. Let us consider participation of asymmetrical and symmetrical time processes in these processes.

 

2.1. Time codes

In neurophysiology, symmetrical and asymmetrical TP (rhythms) have been traditionally considered at comparison of EEG of paired brain hemispheres. Symmetry is associated with synchronization of the EEG rhythms recorded in similar zones of the left and right hemispheres. Desynchronization can be an analogue of asymmetry in the absence of synchronization for one of frequencies of the EEG diapason or of antisymmetry, if (when) one frequency is symmetrical/synchronized, while other EEG fluctuations in two hemispheres are in counterphase. Suggestion of interconnection of symmetrical time processes with synchronization, whereas of asymmetrical ones with desynchronization corresponds to the Noether's theorem and is based on concrete experimental data.

Thus, presentation of a new word to a man for the first 170 ms causes synchronization of EEG rhythms in symmetrical cortex zones of both hemispheres. Such synchronization of rhythms in anterior frontal and temporal zones corresponded to concentration of attention and analysis of this word for up to 184 ms. Subsequent synchronization (of rhythm of 17 Hz) in the speech-associated zones corresponds to cognitive processes and lasts for 460 ms. Other stages of processing of verbal information (or of the 'informational verbal processing') produced asymmetrical desynchronization in correspondence with differences of functions of the left and right brain hemispheres (Ivanitsky et al., 2002). This corresponds to determination of asymmetrical TP as to the consecutively directed one.

Timing of sensory information is known to be the basis for its processing. At present, two main models are considered for encoding of time intervals in the nervous system, that are longer than msec-seconds. One of them considers time parameters of discharge of neurons-oscillators with different basic frequencies; relative to them, other intervals are measured. The other model ascribes count of time (its name) to summation of 'time-dependent' changes of properties of neuron and of states of the local nervous network (the state-dependent networks) (Maas et al., 2002; Karmakar, Buonomano, 2007, etc.). It is to be noted that these changes are estimated relative to previous and subsequent states, i.e., in the current present time. Role of the system acting constantly and maintaining homeostasis is ascribed to the complex of oscillators. The variable component reflecting input of information (of signal) and regulating the 'constant' system (Kryazhimsky, 2007, et al.) can use changes of frequency of neuronal discharge, of complementary synchronization of 'chaotic oscillators', and of synchronization in local nervous networks (Koronovsky, Khramov, 2004; Jakubs et al., 2006). However, a significant role in encoding of time is also played by desynchronization of electric processes in the nervous system (Ivanitsky et al., 2002; Benda et al., 2006; etc.). At the same time, problem of participation of symmetrical and asymmetrical time processes in encoding of intervals of the current time is far from solution.

 

2.2. Regulation of duration of ontogenesis (of life)

 

Participation of rhythms and cycles in regulation of duration of ontogenesis is indicated by the known phenomenon of acceleration of aging processes due to complex or selective disturbances of the rhythm of locomotion (mobility), respiratory and cardiac cycles, circadian cycle of sleep and wakefulness as well as cycles of the reproductive system.

Information of environment is known to have a great novelty and its processing needs significant expenditure of energy and time. A rise of the number of pathologies at advanced and senescent age leads to a decrease of volume of the sensorily perceived exogenous information. In the process of homeostatic regulation of the organism energetic potential and maintenance of optimum of the information volume, these expenditures can be compensated through an increase of the part of endogenous information - from internal receptors as well as the information retrieved from memory and coupled to the past time. Stereotype of the internal information and lower expenditures of energy for its processing lead in this case to acceleration of the subjective time.

On the whole, this affects not only a decrease of duration of the subjective (T_s) present time, but also an increase of its rate in correspondence with the formula

Т_s = Т_ex - Т_end,

where an increase of the part of endogenous information and its coupled Т_end leads to acceleration of subjective feeling of time (-Т_с), whereas an increase of the part of exogenous information and, accordingly, of Т_ex - to deceleration of (+Т_с) (Chernisheva, Nozdrachev, 2006).

Hence, at the senile age, alongside with elimination of creation of programs of the future time, asymmetry of the 'arrow of time' is enhanced due to an increase of the part of the past time. This allows interpreting phenomenon of the 'life in the past' in people of this age category as a mechanism of a decrease of energy cost of maintaining the organism time structure; this mechanism allows a decrease of the rate of processes of the organism aging and homeostasis of the energy potential and volume of information. It seems to be the more successful with increase of the volume of the long-term memory. The same mechanism of use of the information that is coupled with the past time and retrieved from memory can be observed on the background of acute nervous exhaustion (hallucinations) as well as at transition from the slow-wave sleep phase characterized by hypoxia and hypothermia to the rapid-wave phase (dreams) accompanied by activation of visceral systems and by an increase of the body temperature.

It is to be noted that the time processes and the subjective feeling of time, coupled with the present and future time, predominate in children and teenagers at the period of the organism intensive development and perception of huge volumes of exogenous information characterized by a high energy capacity (Surnina, Lebedeva, 2001). The different direction of enhancement of asymmetry of directed time at this age as compared with late ontogenesis period seems to be due to such property of the present as detection and processing of new information [8] accompanied by activation of visceral systems and a rise of the body temperature.

Thus, duration of life can be regulated not only by a change of ratio of symmetric and asymmetric time processes in the organism time structure, but also through an enhancement of asymmetry of asymmetric processes at different periods of ontogenesis. This corresponds to the known increase in the course of evolution of asymmetry of the space-time continuum of living organisms in parallel with the tendency for growth of life duration.