The locked-in patient and the characteristics of the electrical activity of his brain

"Locked-in" state differs from the known states characterized by the motor activity blockade, preservation of conscience of speech contact, despite the fact that connection with outer world during this state is limited only by vertical movements of eyes and eyelids in response to speech signals. Three "locked-in" men were studied at different stages of development of this state. Spectral-coherent analysis of the EEG was conducted. The most typical for the developed state of the "locked-in" man is a uniform change of the intercentral EEG relations. In the motor areas of the cortex alpha-activity and its links are not formed (coherence in alpha-range is zero) while high and low frequencies are coherent. In the visual areas, in contrast, the alpha-rhythm is coherent. Distinct interhemispheric asymmetry of coherent connections appears. In the right hemisphere a decrease of coherence level is sharp and even, in the left one--in occipito-temporal parts the level remains close to norm, while in the frontal parts of the cortex it decreases.     

Eyelid reconstruction in pachydermoperiostosis

Our experience with an unusual case of pachydermoperiostosis is described. This case was accompanied by enlargement of the eyelids, excessive secretions, and difficulty in opening the eyes. Partial and serial excisions of the upper and lower eyelids were done to correct the thickened eyelids. As a result of the operations, this patient can open his eyes fully and the secretions have decreased.     

A putative marker of functional state shift in volunteers after performing a motor task with biofeedback

Statistically significant differences in the stabilometric parameter, an index associated with physical estimation of work, were detected in 13 healthy young volunteers assuming a vertical posture with the eyes closed before and after performing a motor task (a 3-min session of support reaction control with biofeedback). An increase in posture stability after the procedure was accompanied by changes in the power distribution of EEG signals (in the 8–13 Hz range) recorded on the surface of the scalp. The observed effect consisting in an increased postural stability can be interpreted as a “rapid response” to performing a motor task; therefore, it offers the possibility of using a relatively simple approach for the monitoring of switching between functional states associated with various motor procedures and tests.     

Functional organization of the cortex of the large hemispheres during voluntary movement performance: Age aspect

The method of estimation of the coherence (Coh) function values of EEG rhythmic components disclosed the specific features of functional associations of cortical regions during the performance of voluntary graphic cyclic movements under usual and unusual conditions. A significant increase in the Coh function values of the α-rhythm was observed both in the contralateral hemisphere and the symmetrical central and parietal cortical regions in adult subjects during right-hand movement performance with open eyes (usual conditions); in this case the resulting functional associations included motor zone and cortical regions responsible for visual information analysis and perception. During right- and left-hand movement performance with closed eyes (unusual conditions), the mature-type functional organization had a bilateral character with interrelated activity focused in the frontal regions that clearly demonstrated the function of these structures during formation of new motor programs. The significant changes in cortical mechanisms of voluntary graphic movements were disclosed in young 7- to 8- and 9- to 10-year-old schoolchildren.     

Comparison of the quantitative characteristics of ultraslow phasic activity of the brain and the EEG in the states of quiet wakefulness with the eyes open and closed

Quantitative statistical estimates of changes in ultraslow phasic electrical activity of the brain (in the range 0.05–0.5 Hz) and the EEG (1.5–50 Hz) with time were compared in the basic (reference) states of quiet wakefulness with the eyes open and closed (EO and EC, respectively). In both states, the changes in the power and coherence of ultraslow phasic activity and the EEG had similar trends; however, the topographic patterns of the changes were different. The obtained data confirm the assumption on different structural and functional bases of the EEG and ultraslow phasic activity of the brain and indicate polysystemic differences between the EO and EC states.     

Effect of the epiphysis and hypophysis on the circadian organization of the wakefulness-primary sleep cycle in the frog Rana temporaria

Using continuous non-contact registration of the heart rate and motor activity in unrestrained frogs, studies have been made of the effects of hypophysectomy and epiphysectomy on functional state of the organism. It was shown that removal of the epiphysis alleviates the circadian physiological rhythm of natural changes of functional states in wakefulness-primary sleep cycle, whereas removal of the hypophysis results in additional cyclic rhythm of two functional states in the diurnal periodicity of the behaviour. The latter effect is considered to be the ultradian rhythm, which in the intact animals is masked by the circadian one modulated by natural diurnal illumination. It is suggested that removal of the epiphysis reveals endogenous rhythm of the activity typical of periodic regimes of the spontaneous excitation at early stages of ontogenesis.     

Dynamics of the activity of the postural asymmetry factor after unilateral damage to the motor area of the cortex

The authors studied the time-course of functional rearrangements of the segmental apparatus after unilateral injury of the rat motor cortex. It was found that one day after injury the postural asymmetry of the hind limbs was fixed by the lumbal region of the spinal cord. This functional state of the segmental apparatus lasted 10 days after injury in the presence of the maximal activity of postural asymmetry factor (PAF) in the CSF and increasing activity of the factor in the brain tissue. Recovery of the segmental apparatus to symmetrical function by the end of the third week following injury was accompanied by PAF inactivation.     

Features of the Dependences of the “Stimulus–Reaction State” Type

This article deals with the theoretical and applied aspects of the problem of the functional state, its control, and its influence on the quality and reliability of labor activity. The authors define the reflective and regulatory functions of the state and characterize its neurophysiological mechanism. They investigate the features of changes in the quality, physiological cost, and heteromodal errors that emerge when a subject identifies noise-imposed visual images in the range of the functional states of fatigue–negative emotional stress. This procedure is the central element of any operator's activity.     

Self-Recognition of One's Own Fall Recruits the Genuine Bodily Crisis-Related Brain Activity

While bipedalism is a fundamental evolutionary adaptation thought to be essential for the development of the human brain, the erect body is always an inch or two away from falling. Although the neural mechanism for automatically detecting one''s own body instability is an important consideration, there have thus far been few functional neuroimaging studies because of the restrictions placed on participants'' movements. Here, we used functional magnetic resonance imaging to investigate the neural substrate underlying whole body instability, based on the self-recognition paradigm that uses video stimuli consisting of one''s own and others'' whole bodies depicted in stable and unstable states. Analyses revealed significant activity in the regions which would be activated during genuine unstable bodily states: The right parieto-insular vestibular cortex, inferior frontal junction, posterior insula and parabrachial nucleus. We argue that these right-lateralized cortical and brainstem regions mediate vestibular information processing for detection of vestibular anomalies, defensive motor responding in which the necessary motor responses are automatically prepared/simulated to protect one''s own body, and sympathetic activity as a form of alarm response during whole body instability.     

Examination of the eyelid closure defect in trisomy 16 mice

A characteristic feature of trisomy 16 mouse conceptuses is a failure of their eyelids to close. This defect was investigated by examining ocular development in serially sectioned heads of trisomy 16 and normal littermate fetuses from 10 to 18 gestational days. Other heads were examined by using scanning electron microscopy. Between 10 and 15 days, trisomy 16 ocular structures were delayed, but there was no striking abnormal morphology. At 16 days, when the eyelids were closed and fused in normal mice, trisomic eyes had a large cell mass near the inner canthus that protruded between the open lids. The mass was covered by bulbar conjunctiva and cells of the mass were continuous with developing corneal tissue. The mass was not present in the eyes of normal mice on any gestational day and was not present in trisomic eyes at 17 and 18 days, when the lids began to show varying degrees of closure. Based on its positioning at the inner canthus, the mass may represent a transient hyperplasia of the developing semilunar fold which physically impedes lid closure in the trisomic conceptuses. Previously, the defect has been attributed to the trisomy 16 conceptus's overall pattern of growth retardation and delayed development. Masses such as those seen in the trisomic eyes have not been observed in other murine lid-gap defects that have been investigated. A second finding in this study is that trisomic eyes are positioned more superiorly in the head than normal eyes. This variation may be related to alterations in cranial base morphology that are associated with trisomy 16.     

Sculpting the Intrinsic Modular Organization of Spontaneous Brain Activity by Art

Artistic training is a complex learning that requires the meticulous orchestration of sophisticated polysensory, motor, cognitive, and emotional elements of mental capacity to harvest an aesthetic creation. In this study, we investigated the architecture of the resting-state functional connectivity networks from professional painters, dancers and pianists. Using a graph-based network analysis, we focused on the art-related changes of modular organization and functional hubs in the resting-state functional connectivity network. We report that the brain architecture of artists consists of a hierarchical modular organization where art-unique and artistic form-specific brain states collectively mirror the mind states of virtuosos. We show that even in the resting state, this type of extraordinary and long-lasting training can macroscopically imprint a neural network system of spontaneous activity in which the related brain regions become functionally and topologically modularized in both domain-general and domain-specific manners. The attuned modularity reflects a resilient plasticity nurtured by long-term experience.     

Relationship of focal epileptogenesis to hemispheric motor prevalence in human ontogenesis

The authors describe the clinical and electroencephalographic findings in 220 children with focal and secondary generalized epilepsies without gross structural aetiology, with the aim of evaluating the significance of hemispheric motor prevalence for the formation, activity and possibility of compensation of the focus. Focal epileptogenesis was observed significantly more often: a) in partial seizures with elementary symptomatology in the motor non-dominant hemisphere, b) in the motor non-dominant hemisphere in boys, c) in the whole series, irrespective of the form of epilepsy and sex, in the motor nondominant hemisphere in children under the age of six and in the motor dominant hemisphere in children over the age of six. The findings in partial seizures with an elementary motor symptomatology probably arise from the very close relationship to motor areas of the cerebral cortex, in boys from evidently greater hemispheric functional asymmetry than in girls and the age correlation from unequal maturation of functionally identical parts of the brain hemispheres during ontogenesis.     

Disorder-order folding transitions underlie catalysis in the helicase motor of SecA

SecA is a helicase-like motor that couples ATP hydrolysis with the translocation of extracytoplasmic protein substrates. As in most helicases, this process is thought to occur through nucleotide-regulated rigid-body movement of the motor domains. NMR, thermodynamic and biochemical data show that SecA uses a novel mechanism wherein conserved regions lining the nucleotide cleft undergo cycles of disorder-order transitions while switching among functional catalytic states. The transitions are regulated by interdomain interactions mediated by crucial 'arginine finger' residues located on helicase motifs. Furthermore, we show that the nucleotide cleft allosterically communicates with the preprotein substrate-binding domain and the regulatory, membrane-inserting C domain, thereby allowing for the coupling of the ATPase cycle to the translocation activity. The intrinsic plasticity and functional disorder-order folding transitions coupled to ligand binding seem to provide a precise control of the catalytic activation process and simple regulation of allosteric mechanisms.     

Root z-epicanthoplasty in asian eyelids

In the eyelids of Asians, the presence of epicanthal folds and the absence of supratarsal folds are a unique feature. The resulting appearance leads many to seek cosmetic improvement in the medial canthal area. Although many techniques have been described for the elimination of epicanthal folds, scarring and complexity in design are still barriers for surgeons to overcome. From July of 1998 to May of 2000, the authors used root Z-epicanthoplasty on the eyelids of 30 Asian patients to correct epicanthal folds. Results were satisfactory in all patients, with no complications. Root Z-epicanthoplasty, as performed by the authors, is a simple design and procedure; there is minimal scarring in the medial canthal area and no tension.     

大鼠脊髓不完全性损伤后前角运动神经元的酶细胞化学改变

以改良Ａｌｅｎ氏法造成Ｗｉｓｔａｒ大鼠不完全性脊髓损伤,采用神经学功能评分法评定大鼠运动功能,应用定量酶细胞化学方法观察脊髓前角运动神经元内乙酰胆碱酯酶（ＡＣｈＥ）和酸性磷酸酶（ＡｃＰ）活性变化。结果显示：１．脊髓损伤后大鼠运动功能障碍,随后逐渐恢复。２．前角运动神经元内ＡＣｈＥ活性减弱、ＡｃＰ活性增强;随后酶活性呈逐渐恢复,四周时ＡＣｈＥ活性基本恢复正常。结果说明：大鼠脊髓不完全性损伤后运动功能变化与前角运动神经元的功能状态具有较强的相关性;前角运动神经元在不完全性脊髓损伤运动功能恢复中起重要作用。     

Computerized method for study of temporal characteristics of sensorimotor reactions in preschool and first-grade schoolchildren

A computerized technique for estimation of the reaction time of motor responses to visual stimuli was advanced. The testing includes three stages. The following kinds of reactions were studied: simple reactions at the first stage, simple choice between 2 and 4 alternatives at the second stage, and, finally, reactions of the complex choice between 2 and 4 alternatives at the third stage. The authors think that each kind of reactions reflects specific components of child's sensorimotor activity. It is planned to study the rate of ontogenetic development of different links included into the functional system of voluntary sensorimotor reactions (perceptual, motor, decision making and others) using the proposed technique.     

Postembryonic eye degeneration in the troglobitic salamander Typhlotriton spelaeus

Comparative histological observations of the eyes of Typhlotriton spelaeus and several epigean, plethodontid species indicate that the principal postembryonic degenerative changes in the eyes of T. spelaeus involve the eyelids and cornea, visual cells, outer plexiform layer, and the pigment epithelium. Ordinarily these changes were initiated after metamorphosis, before attainment of sexual maturity, but a few larvae had degenerating retinae. The corneal epithelium becomes irregular and thin as eyelids develop during and after metamorphosis, but retains its larval structure in animals in which eyelid overlap is incomplete. Disruption and vacuolation of the lens sometimes occurs in postmetamorphic animals with degenerating visual cells. Retinal degeneration involves reduction of the inner and outer segments of visual cells, loss of the outer plexiform layer, and retraction of apical processes of the pigment epithelium. In its earliest stage, retinal reduction is first apparent at the retinal margin where visual cells are normally less well-differentiated, but in its terminal stage reduction has gone to completion over the entire retina. Extent of retinal degeneration in adults is directly related to postmetamorphic age but there is variability in each age group. Females generally have smaller eyes, and more extensive degeneration of visual cells than males. The loss of visual function in adults is correlated with extensive visual cell degeneration.     

Dictyostelium myosin-5b is a conditional processive motor

Dictyostelium myosin-5b is the gene product of myoJ and one of two closely related myosin-5 isoenzymes produced in Dictyostelium discoideum. Here we report a detailed investigation of the kinetic and functional properties of the protein. In standard assay buffer conditions, Dictyostelium myosin-5b displays high actin affinity in the presence of ADP, fast ATP hydrolysis, and a high steady-state ATPase activity in the presence of actin that is rate limited by ADP release. These properties are typical for a processive motor that can move over long distances along actin filaments without dissociating. Our results show that a physiological decrease in the concentration of free Mg(2+)-ions leads to an increased rate of ADP release and shortening of the fraction of time the motor spends in the strong actin binding states. Consistently, the ability of the motor to efficiently translocate actin filaments at very low surface densities decreases with decreasing concentrations of free Mg(2+)-ions. In addition, we provide evidence that the observed changes in Dd myosin-5b motor activity are of physiological relevance and propose a mechanism by which this molecular motor can switch between processive and non-processive movement.     

The effect of motor training on evoked sensorimotor cortex potentials in rats during ontogenesis]

Investigation into the influence of motor training on the functional activity of the rat sensorimotor cortex in ontogenesis has shown that three to four-month training, starting at the age of four weeks, leads to a statistically significant enhancement of sensorimotor cortex activity both by latencies and recovery cycles durations. A similar six to seven-month locomotor training produces the same statistically significant results. The differences in the shifts of functional activity after motor training observed between two age groups are not statistically significant. The probability of changes in the average definitive electrophysiological parameters of functional activity after motor training observed between two age groups are not statistically significant. The probability of changes in the average definitive electrophysiological parameters of functional activity of the sensorimotor cortex is suggested in rats aged more than a month, as a result of individual experience.     

Effect of constant light on the circadian rhythm in locomotor activity in intact or eyelids-removed rats

According to the Aschoff's role, exposure to continuous light (LL) results in the elongation of the free-running period of the rat circadian rhythm. However, the LL may not always mean the constant intensity of the light for the suprachiasmatic nucleus, since the rat may regulate the contrast of the illumination by their eyelids which are closed during the sleep phase. In this study, the surgical removal of the eyelids under the LL caused arrhythmicity of the locomotor activity in 7 of 10 rats. The remaining 3 rats maintained the free-running rhythm after the removal of the eyelids. These results suggest that constant light may affect the free-running rhythm of the rat with or without eyelids in the different manner.