On the accuracy of evaluations of temporal characteristics of visual perception

We studied the accuracy of evaluations of the temporal characteristics of visual perception: critical frequency of light flickers, time of perception, and time of visual analyzer recovery. Results of comparison of the accuracy of evaluations are presented. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 144, No. 8, pp. 236–237, August, 2007     

Neuromagnetic functional Localization: Principles,state of the art,and perspectives

The neuromagnetic method has been providing impressive results in the understanding of the functions and of some pathologies of the human brain. The possibility of achieving three-dimensional source localization represents a fundamental step forward in the study of the organization of cortical areas, in that of focal disorders and, in general, in the investigation of brain information processing. The development of large multichannel systems to achieve real time functional localization is being carried on in several countries and the first prototypes are already operating for a full assessment of the benefits of the technique. The use of time-varying magnetic pulses provides the opportunity for non-invasive stimulation of the central nervous system toward the achievement of functional imaging of the motor cortices.     

Lymphocyte homing to the gut: attraction, adhesion, and commitment

Summary: Lymphocytes continuously migrate from the blood into the intestine. Naive lymphocytes leave the blood through high endothelial venules in Peyer's patches. During the multistep extravasation cascade, they sequentially roll on, firmly adhere to, and transmigrate through the endothelial layer using multiple adhesion molecules and chemotactic signals. In the organized lymphoid tissues of the gut, lymphocytes can become activated, if they meet their cognate antigens transported to Peyer's patches through the gut epithelium. During activation and proliferation, the lymphocytes become imprinted by the local dendritic cells, so that after returning to systemic circulation via the efferent lymphatic vasculature, they preferentially home to lamina propria of the gut to execute their effector functions. In inflammation, the recirculation routes of lymphocytes are altered, and these may explain the pathogenesis of certain extra‐intestinal manifestations of gut infections and inflammatory bowel diseases. The increased knowledge on the mechanisms that regulate lymphocyte homing and imprinting has clear applicability in designing more effective vaccination regimens. A detailed understanding of the mucosal homing has recently led to the development of the first successful anti‐adhesive therapeutics in human.     

Structural and functional neural correlates of music perception

This review article highlights state-of-the-art functional neuroimaging studies and demonstrates the novel use of music as a tool for the study of human auditory brain structure and function. Music is a unique auditory stimulus with properties that make it a compelling tool with which to study both human behavior and, more specifically, the neural elements involved in the processing of sound. Functional neuroimaging techniques represent a modern and powerful method of investigation into neural structure and functional correlates in the living organism. These methods have demonstrated a close relationship between the neural processing of music and language, both syntactically and semantically. Greater neural activity and increased volume of gray matter in Heschl's gyrus has been associated with musical aptitude. Activation of Broca's area, a region traditionally considered to subserve language, is important in interpreting whether a note is on or off key. The planum temporale shows asymmetries that are associated with the phenomenon of perfect pitch. Functional imaging studies have also demonstrated activation of primitive emotional centers such as ventral striatum, midbrain, amygdala, orbitofrontal cortex, and ventral medial prefrontal cortex in listeners of moving musical passages. In addition, studies of melody and rhythm perception have elucidated mechanisms of hemispheric specialization. These studies show the power of music and functional neuroimaging to provide singularly useful tools for the study of brain structure and function.     

Speech perception as a window for understanding plasticity and commitment in language systems of the brain

In this article, we provide a critical review of the literature on speech perception and phonological processing in infancy, and in populations with different experiential histories as a window to understanding how the notion of critical periods might apply to the acquisition of one part of language: the sound system. We begin by suggesting the use of the term "optimal period" because (a) both the onset (opening) and offset (closing) of openness to experience is variable rather than absolute and (b) phonological acquisition involves the emergence of a series of nested capabilities, each with its own sensitive period and each best explained at one of several different levels of specificity. In support, we cite evidence suggesting that to fully understand plasticity and commitment in phonological acquisition, it is necessary to consider not only the biological and experiential factors which may contribute to the onset and the offset of openness to experience but also how the sequentially developing parts of phonology constrain and direct development. In summary, we propose a nested, cascading model wherein biology, experience, and functional use each contribute.     

Index of the functional state of the liver

A combination of laboratory tests, providing the most valuable quantitative assessment of hepatic function at large was selected with the aid of an EC-1020 computer on the basis of the investigation of 124 hepatic patients and 15 normal subjects. This combination was termed the hepatic functional index (HFI); it was determined by the PTI (prothrombin index) to RETk (blood Bengal rose retention) ratio, expressed as a percentage. Quantitative criteria of normal and abnormal hepatic activity, with subdivisions by severity, have been proposed on the basis of HFI estimations in patients with varying degrees of hepatic failure and in normal subjects.     

Turn-off, drop-out: functional state switching of cadherins.

The classic cadherins are a group of calcium dependent, homophilic cell-cell adhesion molecules that drive morphogenetic rearrangements and maintain the integrity of cell groups through the formation of adherens junctions. The formation and maintenance of cadherin-mediated adhesions is a multistep process and mechanisms have evolved to regulate each step. This suggests that functional state switching plays an important role in development. Among the many challenges ahead is to determine the developmental role that functional state switching plays in tissue morphogenesis and to define the roles of each of the several regulatory interactions that participate in switching. One correlate of the loss of cadherin-mediated adhesion, the "turn-off" of cadherin function, is the exit, or "drop-out" of cells from neural and epithelial layers and their conversion to a motile phenotype. We suggest that epithelial mesenchymal conversions may be initiated by signaling pathways that result in the loss of cadherin function. Tyrosine phosphorylation of beta-catenin is one such mechanism. Enhanced phosphorylation of tyrosine residues on beta-catenin is almost invariably associated with loss of the cadherin-actin connection concomitant with loss of adhesive function. There are several tyrosine kinases and phosphatases that have been shown to have the potential to alter the phosphorylation state of beta-catenin and thus the function of cadherins. Our laboratory has focused on the role of the nonreceptor tyrosine phosphatase PTP1B in regulating the phosphorylation of beta-catenin on tyrosine residues. Our data suggest that PTP1B is crucial for maintenance of N-cadherin-mediated adhesions in embryonic neural retina cells. By using an L-cell model system constitutively expressing N-cadherin, we have worked out many of the molecular interactions essential for this regulatory interaction. Extracellular cues that bias this critical regulatory interaction toward increased phosphorylation of beta-catenin may be a critical component of many developmental events.     

Intrinsically organized network for face perception during the resting state

We investigated 0.01–0.08 Hz low-frequency fluctuations of BOLD-fMRI signals in the face and object-responsive regions during the resting-state and during face or object viewing tasks. By comparing the effects of the face-responsive regions of interest with those of the object-responsive regions of interest, we observed a distributed cortical network of face perception during the resting-state among posterior fusiform gyrus, inferior occipital gyrus, and superior temporal sulcus. This network was also significantly activated during the face perception task. The face perception task also activated additional areas in the frontal and parietal regions. Our results suggest that the “core” but not the “extended” network for face processing is already in some form of activation during the resting-state. A possible function of the resting-state face perception network is perhaps to prepare the brain to process faces that individuals are highly likely to encounter in their environment.     

Evaluation of the functional state of the leprous macrophages

Cytochrome oxidase (CCO), peroxidase, succinic dehydrogenase (SDG) and NADH-diaphorase were studied electron-cytochemically in leprous macrophages (LM) of granulomas of patients suffering from lepromatous leprosy. The LM peroxidase activity and location differed, this affecting the completeness of M. leprae phagocytosis. High CCO activity in LM cytoplasm was not a factor essentially influencing M. leprae disintegration. SDG and NADH-diaphorase, locating predominantly in membraneous structures of M. leprae, show low activity in LM cytoplasm.     

Disturbances in the functional state of the liver in dogs subjected to Strontium-90

Summary Strontium-90, administered orally to dogs in a dose of 1 millicurie/kg caused disturbances in the carbohydrate metabolism of the liver, changes in the hepatic tissue, and a reduction in bile formation and bile excretion. Pathomorphological investigations demonstrated injury to the liver tissue, dilatation of the vessels (which was more marked in the center of the lobules), and early necrobiosis of individual hepatic cells. The total dose built up by the administration of Strontium-90 (in 180 days) was equal to 10–15 rads.(Presented by Active Member of the Academy of Medical Sciences, USSSR A. V. Lebedinskii) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 57, No. 2, pp. 29–33, February, 1964     

Morphological and functional state of the heart during magnetic storm

Magnetic storm modulates morphological and functional state of the heart and the related systems. Changes in cardiomyocyte ultrastructure induced by changes in geomagnetic activity were studied in experiments on rabbits. We describe a possible mechanism underlying changes in cardiac activity in intact animals induced by geomagnetic perturbations. The most pronounced alterations of cardiomyocyte ultrastructure were observed during the major phase of magnetic storm.     

B-cell commitment, development and selection

Summary: Here we review three areas in B-cell development in the mouse, with a focus on relevance to B-1/CD5+ B cells. Multiparameter flow cytometry has allowed the dissection of intermediate stages of developing B cells, both in fetal liver and bone marrow. In the first area, we present recent work that has delineated a fraction of pre-pro-B cells, committed to the B lineage, but lacking any immunoglobulin rearrangements. Next, the role of the pre-B-cell receptor in B-cell repertoire selection has become clear in the past few years, but we present work suggesting that the action of this process during fetal life is different, resulting in selection of a very distinct repertoire compared with adult. Finally, we describe a new VH3609 antithymocyte Ig transgenic mouse model system that has provided the first definitive evidence for the role of self-antigen in development and maintenance of natural autoreactive B cells.     

Effects of commitment to abstinence, positive moods, stress, and coping on relapse to cocaine use

In a prospective study of 104 cocaine patients, a baseline assessment was conducted while Ss were in treatment. After treatment completion, Ss were assessed once a week for 12 weeks, then 6 months from study start. A goal of absolute abstinence, greater expected success in quitting, and positive moods predicted a lower risk of a lapse in the first 12 weeks of follow-up. Stress (negative moods, physical symptoms, hassles, and life events) did not predict. Use of more coping strategies predicted abstinence for Caucasian but not for African-American Ss. Baseline measures of expected success and desire to quit predicted continuous abstinence at 6 months but not at statistically significant levels. Results suggest that solidifying abstinence goals and enhancing positive moods may facilitate early abstinence.     

The functional state of the pituitary-adrenal system during digestion

Summary The activity of the pituitary-adrenal system was determined by the number of 17-hydroxycorticosteroids and eosinophils in the blood. As demonstrated, nutritional stimuli (meat, milk, bread) caused a rise in the 17-hydroxycorticosteroid concentration and reduction in the number of eosinophils. The analysis of the mechanism of stimulation of the system demonstrated that its activation during digestion occurs under the effect of the reflex mechanisms. At later digestive periods this activation may be caused by the action of digestive products.(Presented by Active Member AMN SSSR S. V. Anichkov) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 55, No. 1, pp. 21–25, January 1963