A Graphic Comparison Between the Current-Voltage Curves of an Electrochemical Generator and Living Unstressed Rabbit Tibia

Unstressed living bone exhibits bioelectric potential differences along its surface. This electrogenic behavior has been characterized by a V=f(l) curve which is linear up to a certain limit. To better understand the origin and meaning of these potentials and to better describe this electrogenic behavior an electrochemical generator (a silver-oxide cell) was included, instead of bone, into the same measurement situation used to describe the V=f(I) curve of the rabbit tibia. The V=f(I) curve of the cell was graphically compared with the V=f(I) curve of the living unstressed rabbit tibia: the two curves were superimposable. This suggests that an electrochemical mechanism may be at the origin of the bioelectric potentials in unstressed living bone.     

Features of EEG in patients with disorders due to psychoactive substance use during olfactory stimulation

Electroencephalographic (EEG) spectra have been analyzed under baseline conditions and during olfactory stimulation in substance-dependent and healthy subjects. The intergroup differences in the EEG spectra resulting from an increase in the power of cortical bioelectric potentials in patients with disorders due to psychoactive substance use were recorded in the parietal and temporal EEG leads. Interhemispheric differences have been found in the contribution of different frequencies to the spectral characteristics of the EEG. In patients with addictive disorders, in the temporal area of the left hemisphere, in the high-frequency range, a significant increase in the power of bioelectric potentials was recorded under baseline conditions and during olfactory stimulation. An increased power of α activity was typical of the temporal area of the right hemisphere in patients with disorders due to psychoactive substance use compared to the healthy subjects. The neurophysiological patterns found may be related to the psychological and behavioral features of addictive disorders.     

Influence of informational oversaturation on the quality of creative activity and spatial organization of EEG

The features of the spatial organization of bioelectric potentials in the cases of successful and unsuccessful creative imagination (refusal or poor quality of the product) under conditions of informational oversaturation. Two groups of subjects were compared: professionals (23 healthy students of the Department of Graphic Arts) and non-professionals (34 persons whose specialties were not linked with systematic visual imagination). During the experiments, the subjects were asked to mentally create a visual image based on two simple graphic elements, a right angle and a diagonal; after recording the EEG, they had to draw the image on paper and give it a title. The total number of elements exceeded 7 ± 2; hence, information processing at the conscious level was impossible, which caused the necessity of involving the mechanisms of unconscious information processing. The quality of the created product was evaluated with regard to the degree of success of performing the task and the features of spatial EEG organization. The EEG was recorded from 24 scalp sites of a subject using a SIT-EEG portable telemetric device. In the case of the successful performance of the task by professionals, the parameters of spatial organization of bioelectric potentials, i.e., spatial synchronization (linear processes) and spatial disorder (non-linear process) were strengthened compared to the base-line level in the frontal temporal areas of the right hemisphere and parietal occipital areas of the left hemisphere. Conversely, in the nonprofessionals, these parameters increased in the frontal temporal areas of the left hemisphere and parietal occipital areas of the right hemisphere. In the case a task was not successfully performed by the professionals, the spatial disorder of bioelectric potentials increased in all the cortical areas; in the nonprofessionals, only weak changes were observed. In all situations, the groups differed also in the parameters of coherence (Coh), spectral power (Sp) of bioelectric potentials, and informational energy, which reflects the level of expenditure of the brain’s energy for information processing. The evidence obtained is interpreted in terms of electroencephalographic correlates of successful task performance by professionals and nonprofessionals, i.e., their creative imagination under the conditions of informational over-saturation.     

The EEG spatial pattern and psychophysiological characteristics of divergent and convergent thinking in humans

The psychophysiological parameters of the spatial synchronization of bioelectric potentials during the nonverbal divergent, nonverbal convergent, verbal divergent and verbal convergent thinking have been analyzed. The relationships between the performances of tests for these thinking styles were different. The strongest significant correlation has been found between the productivities of the verbal divergent and verbal convergent thinking styles; the weakest correlation, between those of the nonverbal divergent and nonverbal convergent thinking styles. The thinking styles differ from one another in the topography of spatial synchronization of bioelectric potentials. They are the most pronounced during the two nonverbal tasks and the least pronounced during the two verbal tasks. The thinking styles also differ from one another in the degree of the enhancement of the coherence between bioelectric potentials during tasks compared to the baseline (with the eyes open). Some human psychophysiological characteristics facilitating the performance of divergent (creative) tasks have a negative effect on the performance of convergent (noncreative) tasks. The data are discussed in terms of the differences in the level of general activation and involvement of different types of information processing (simultaneous and successive).     

Posttetanic changes in hippocampal minimal evoked potentials

Changes in the EEG induced by a single spike were recorded in the hippocampus of an unanesthetized rabbit. Summation of focal electrical activity synchronous with spontaneous single unit discharges at the symmetrical point of contralateral hemisphere revealed no stable potentials which could reflect these changes. In two cases discharges identified as activity of Shaffer's collaterals were recorded in area CA₁. Summation of post-spike changes in evoked activity recorded by the same microelectrode showed stable negative waves with an amplitute of 40–60 µV, which could have been evoked by single spikes. The curve of amplitude of the averaged evoked potentials versus near-threshold current strength stimulating the intrahippocampal pathways was not smooth in most experiments but stepwise in character. It is suggested that the minimal evoked potential corresponding to the first step (amplitude 40–80 µV) reflects a response to stimulation of one fiber. After above-threshold tetanization prolonged posttetanic potentiation of the minimal evoked potentials did not arise in CA₁ in response to stimulation of Shaffer's collaterals. Minimal evoked potentials recorded in area CA₃ in response to stimulation of the dentate fascia showed clear potentiation. The results are in agreement with the hypothesis of the synaptic localization of the mechanisms responsible for prolonged posttetanic potentiation.Brain Institute, Academy of Medical Sciences of the USSR, Moscow. Translated from Neirofiziologiya, Vol. 9, No. 2, pp. 124–134, March–April, 1977.     

Spontaneous and neurally evoked contractions of visceral muscles in the oviduct of Locusta migratoria

The oviducts of Locusta migratoria are innervated by a pair of nerves which arise from, the seventh abdominal ganglion. A distinctive network of striated muscle fibres occurs in the oviducts. The lateral oviducts and common oviduct consist of an inner circular layer of muscle and an outer longitudinal layer of muscle. At the junction of the lateral and common oviduct an additional thin longitudinal layer is found adjacent to the basement epithelium. The oviducts contracted spontaneously when isolated from the central nervous system. These myogenic contractions took the form of peristaltic contractions in the lateral oviduct, and intermittent phasic-like contractions of the posterior regions of the lateral oviduct and the common oviduct. These phasic-like contractions were associated with individual complex potentials recorded extracellularly from the muscle fibres. In locusts that had been interrupted in the process of egg laying, there were large-amplitude action potentials, firing in a bursting pattern, in the oviducal nerves. These large action potentials were absent in locusts that had not been egg-laying. These action potentials were associated with both bioelectric potentials and mechanical events in the posterior region of the lateral oviduct and the common oviduct. Electrical stimulation of the oviducal nerve mimicked the effects of spontaneous action potentials, resulting in the appearance of monophasic potentials and contractions. The contractions were graded and dependent upon both frequency and duration of stimulation. It is concluded that the oviducts of Locusta are both myogenic and neurogenic. The role of these contractions in oviposition is discussed.     

The Electrophysiological Organization of the Embryonic Chick Heart

Both intracellular and surface electrodes were employed to record electrical activity from embryonic chick hearts between the ages of 3 and 20 days. Cells from the sinus venosus, sinoatrial (SA) valves, atrium, atrioventricular (AV) ring, and ventricle were localized and characterized on the basis of shape, amplitude, rise time, and duration of transmembrane potentials. The differences in transmembrane potentials from these various regions provided the basis for a hypothesis concerned with the distribution of pacemaker potentiality and one related to the origin of the His-Purkinje system. Action potentials recorded along the entire embryonic AV ring were comparable to those of the adult rabbit AV nodal cells in both configuration and sequence of activation and were thus categorized into three functional regions (AN, N, NH). Histological sections of 7 and 14 day hearts demonstrated muscular continuity between the right atrium and ventricle across the muscular AV valve.     

Evaluation of reference sites for scalp potentials evoked by painful and non-painful sural nerve stimulation

The objective of this study was to evaluate reference sites for recording the middle- and long-latency scalp potentials elicited by painful and non-painful sural nerve stimulation. Somatosensory evoked potentials (SEPs) were recorded from the scalp, the mastoid, the earlobe, the neck, and the wrist. Each site was referenced to the sterno-vertebral (SV) electrode, which is a balanced non-cephalic reference with essentially no ECG contamination.There was little or no activity recorded between the wrist and SV, and the SV was located within a region extending from the rostral neck to the wrist where the potentials were stable over space. Hence, the SV reference is indifferent for the middle- and long-latency potentials evoked by painful and non-painful sural nerve stimulation. There was, however, significant activity recorded from the earlobe and mastoid, sites which are frequently used as references for the SEP. It is important that investigators using these cephalic references to study the middle- and long-latency peaks of the SEP be aware of this activity as it will distort SEPs recorded from single sites and the SEP scalp topography, distortions which could unnecessarily complicate their interpretation.     

EEG spatial organization during intense hyperventilation (cyclic breathing): II. EEG correlates of psychovisceral phenomena

EEG correlates of two main effects of long-term hyperventilation (cyclic breathing similar to rebirthing), namely, psychotic manifestations and sensations in internal organs, are considered. Standard EEGs of 44 subjects were recorded and subsequently treated by multiparametric methods. It was shown that, in the case of psychotic phenomena (hallucinations, visual and auditory images, different scenes, virtual travels, out-of-body experiences, etc.), the changes in the spatial organization of bioelectric potentials as compared with the baseline have different patterns than in the case of sensations in internal organs. The changes are observed in the frontal regions of the cortex: a decrease in spatial synchronization (linear processes) during an increase in spatial disarray (nonlinear processes) of bioelectric potentials and the intensifying of high-frequency β activity. If sensations in internal organs appear, a decrease in the above parameters was observed in the right hemisphere and in posterior cortical areas. The data are discussed from the viewpoint of qualitative specificity of changes in functional states during an altered state of consciousness with manifestations of different psychovisceral phenomena.     

On the block of outward potassium current in rabbit Schwann cells by internal sodium ions.

Currents through delayed rectifier-type K+ channels in Schwann cells cultured from rabbit sciatic nerve were studied with patch-clamp techniques. When the internal and external solutions contained physiological concentrations of sodium, the amplitude of these outward currents declined as the cell was depolarized to potentials above about +40 mV, despite the increased driving force. This reduction in the amplitude of outward K+ currents was observed in many cells before the subtraction of leakage currents; it was also observed for ensemble currents recorded in outside-out patches. It was therefore not the result of a leak-subtraction artefact nor of inadequate voltage-clamp control. Several lines of evidence also suggested that it was not the result of the extracellular accumulation of K+. By contrast, when the Na+ ion concentration of the internal solution was nominally zero, the reduction in the amplitude of outward K+ currents at positive membrane potentials was not observed. The apparent amplitude of single-channel currents through two types of K+ channel was reduced by 30 mM internal Na+, apparently as the result of a rapid 'flickery' block. The results suggest that channel block by internal Na+ is largely responsible for the negative slope conductance seen in current-voltage plots of whole-cell K+ currents at positive membrane potentials. In addition, our analysis of single-channel currents suggests that the current-voltage curve for a delayed rectifier channel in rabbit Schwann cells (in the absence of internal Na+) is roughly linear with internal and external K+ concentrations of 140 mM and 5.6 mM, respectively.     

Electroosmosis in Nitella

The role of electroosmosis was studied directly in Nitella. The cells were mounted in a water-tight barrier between two chambers containing reversible electrodes for the application of potentials, and fitted with calibrated capillaries to measure water movement. No water movement was found when small existing bioelectric potentials were short-circuited through an external connection, nor when external potentials up to 1 or 2 volts were applied (producing currents up to 5 microa). Higher potentials (up to 10 volts) caused small movements of water, toward the negative pole. Larger and often irreversible water movements were produced by potentials up to 20 volts-sometimes persisting after current flow. A variety of evidence suggests that the effects are caused by injury at the cathodal end of the cell, allowing water to be attracted osmotically at the intact end and forced out at the injured end (transosmosis). This injury is reversible under small applied potentials, irreversible after large ones (100 to 200 times the natural bioelectric values). Such water flows persist in low salt concentrations (up to 0.09 M NaCl) but almost completely vanish in isotonic (0.26 M) mannitol. This confirms the osmotic, rather than the electroosmotic nature of the water movement. It is estimated that electroosmosis cannot account for more than 1 per cent of the water movement (or turgor) in Nitella cells. The dead cellulose walls display a small electroosmotic water flow at very high current densities (under 20 volts applied potential).     

Plutonium in bone: a high resolution autoradiographic study using plutonium-241.

Plutonium-241 citrate solution at pH 6-5 was injected intravenously into hamsters and an adult rabbit at a dose of 10 kBq g-1 (260 nCi g-1). The hamsters were killed serially at 15 min, 2 hours, 1 day, 10 days, 1 month and 6 months after injection and the rabbit at 1 week. Their knee-joints or femora were examined for plutonium-241 by autoradiography. Few differences were found between the pattern of plutonium distribution in the hamsters and the rabbit. The results showed that although plutonium is initially distributed on bone surfaces, at long periods after injection it becomes deposited throughout the bone matrix. Plutonium uptake by cells in resorbing areas of periosteum, in active osteoblasts, and in chondrocytes in regions of cartilage mineralization was rapid. Plutonium concentrated more slowly on the resting bone surfaces and at sites of low metabolic activity. In addition, some unlabelled sections of skeletal tissues were immersed in a plutonium-241 citrate solution. When autoradiographed, it was found that plutonium was bound by cell nuclei, tooth enamel matrix, dentine, predentine and bone matrix. Plutonium binding to cartilage matrix was weak. The results are discussed with reference to the literature, and a model is proposed to explain the distribution pattern and fate of plutonium deposits in bone.     

Holding potential affects the apparent voltage-sensitivity of sodium channel activation in crayfish giant axons.

Sodium channel activations, measured as the fraction of channels open to peak conductance for different test potentials (F[V]), shows two statistically different slopes from holding potential more positive than -90 mV. A high valence of 4-6e is indicated a test potentials within 35 mV of the apparent threshold potential (circa -65 mV at -85 mV holding potential). However, for test potentials positive to -30 mV, the F(V) curve shows a 2e valence. The F(V) curve for crayfish axon sodium channels at these "depolarized" holding potentials thus closely resembles classic data obtained from other preparations at holding potentials between -80 and -60 mV. In contrast, at holding potentials more negative than -100 mV, the high slope essentially disappears and the F(V) curve follows a single Boltzmann distribution with a valence of approximately 2e at all potentials. Neither the slope of this simple distribution nor its midpoint (-20 mV) was significantly affected by removal of fast inactivation with pronase. The change in F(V) slope, when holding potential is increased from -85 to -120 mV, does not appear to be caused by the contribution of a second channel type. The simple voltage dependence of sodium current found at Vh -120 mV be used by to discriminate between models of sodium channel activation, and rules out models with three particles of equal valence.     

Bioelectric potential changes in the style of Lilium longiflorum Thunb. after self- and cross-pollination of the stigma

Two different types of bioelectric potential changes have been registered in the style of Lilium longiflorum cv. Arai 5 after different treatments of the stigma. Self-pollination induces a bioelectric potential change different from the potential change induced by cross-pollination. Removal of the stigma or apllication of killed compatible pollen induced a bioelectrical response similar to the potential change recorded after cross-pollination. No bioelectric potential change was recorded after application of pollen of Petunia hybrida, pollen of Haemanthus katherinae, killed self-pollen, or no treatment at all.The mean generation time of the bioelectric potential change was 338 min after the treatment. The translocation velocity varied between 1.2 and 5.4 cm h^-1. Both responses are similar to the potential changes registered in Mimosa pudica after different types of stimulation and to the potential changes generated by the phytochrome in Avena coleoptiles. The translocation of the signals is discussed in relation to the models on the translocation in Mimosa. The relation between the bioelectric potential changes and the incompatibility reaction in Lilium longiflorum is discussed.     

Bioelectricity and epimorphic regeneration

All cells have electric potentials across their membranes, but is there really compelling evidence to think that such potentials are used as instructional cues in developmental biology? Numerous reports indicate that, in fact, steady, weak bioelectric fields are observed throughout biology and function during diverse biological processes, including development. Bioelectric fields, generated upon amputation, are also likely to play a key role during vertebrate regeneration by providing the instructive cues needed to direct migrating cells to form a wound epithelium, a structure unique to regenerating animals. However, mechanistic insight is still sorely lacking in the field. What are the genes required for bioelectric‐dependent cell migration during regeneration? The power of genetics combined with the use of zebrafish offers the best opportunity for unbiased identification of the molecular players in bioelectricity. BioEssays 29:1133–1137, 2007. © 2007 Wiley Periodicals, Inc.     

Ansätze zur quantitativen Analyse der Nachrichtenaufnahme und -verarbeitung in biologischen Rezeptoren

The flux equilibrium theory, used for interpretating active and passive ion transport, can explain the generation of receptor potentials. In a model, driving forces and velocity coefficients are represented by the parameters of electric circuits. From these membrane models ionic fluxes can be calculated quantitatively on the basis of transport equations. These equations are derived from the theory of irreversible thermodynamic processes. Receptor models allow a simulation and prediction of the bioelectric potentials which were recorded by other authors in neuro-physiological experiments under various stimulus conditions. The information capacity of a single receptor channel is determined by the ionic flux and the stimulus parameters. In combination with the network of neuron models, receptor models can be used in a perception. The problems of on-off-activation and lateral inhibition were investigated with such a network.     

Estimation of monopolar signals from sphincter muscles and removal of common mode interference

The detection of surface electromyogram (EMG) by multi-electrode systems is applied in many research studies. The signal is usually recorded by means of spatial filters (linear combination of the potential under at least two electrodes) with vanishing sum of weights. Nevertheless, more information could be extracted from monopolar signals measured with respect to a reference electrode away from the muscle. Under certain conditions, surface EMG signal along a curve parallel to the fibre path has zero mean (property approximately satisfied when EMG is sampled by an array of electrodes that covers the entire support of the signal in space). This property allows estimating monopolar from single differential (SD) signals by pseudoinversion of the matrix relating monopolar to SD signals. The method applies to EMG signals from the external anal sphincter muscle, recorded using a specific cylindrical probe with an array of electrodes located along the circular path of the fibres. The performance of the algorithm for the estimation of monopolar from SD signals is tested on simulated signals. The estimation error of monopolar signals decreases by increasing the number of channels. Using at least 12 electrodes, the estimation error is negligible. The method applies to single fibre action potentials, single motor unit action potentials, and interference signals.The same method can also be applied to reduce common mode interference from SD signals from muscles with rectilinear fibres. In this case, the last SD channel defined as the difference between the potentials of the last and the first electrodes must be recorded, so that the sum of all the SD signals vanishes. The SD signals estimated from the double differential signals by pseudoinvertion are free of common mode.     

Assessment of the Ability of the Bioelectric Effect To Eliminate Mixed-Species Biofilms

Microbes have been able to persist in water distribution systems through the development of multicellular communities known as biofilms. This study evaluated the usefulness of the bioelectric effect for the elimination of water distribution system biofilms from annular reactors. The bioelectric effect did not have any bactericidal action either alone or when coupled with free chlorine.     

Age-related characteristics of the formation of neurophysiological mechanisms of the phonemic, grammatical, and semantic linguistic levels

The structure of regional interactions of brain bioelectric potentials has been studied during performance by adults (n = 18) and children aged five to six (n = 15) and eight to nine years (n = 17) of three analytical verbal tasks: recognition of a given phoneme in the context of auditory presented words and recognition of grammatical and semantic mistakes in auditory presented sentences. According to the data of cross-correlation and coherent EEG analyses, adults and, to a lesser extent, children of both age groups showed a noticeable intensification of interhemispheric interaction during the performance of all three tasks, especially between temporal areas, with relatively minor changes in ipsilateral EEG relations. Children were shown to have elements of immaturity of neurophysiological mechanisms underlying various aspects of the language function, such as the analysis of the grammatical formation of a verbal utterance and the semantic content of a phrase. The results also suggest that the level of maturation of neurophysiological mechanisms underlying phonemic analysis is somewhat higher at these age stages than the level of maturity of central mechanisms responsible for the analysis of the semantic content and grammatical construction of a phrase. Quantitative comparison of the patterns of spatial interaction of cortical bioelectric potentials recorded during the performance of the tasks related to different linguistic levels showed a high degree of their statistical similarity for each of the age groups. The findings confirm the assumption that the distributive central maintenance of different linguistic levels is based on topologically close constellations of interacting cortical areas and on similar organization of their regional interactions.     

Assessment of the ability of the bioelectric effect to eliminate mixed-species biofilms

Microbes have been able to persist in water distribution systems through the development of multicellular communities known as biofilms. This study evaluated the usefulness of the bioelectric effect for the elimination of water distribution system biofilms from annular reactors. The bioelectric effect did not have any bactericidal action either alone or when coupled with free chlorine.