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PubMedDate not supplied

[Dynamics of tuning to orientation of cross-like figures in neurons from the cat visual cortex].

Dynamics of tuning to orientation of flashing light bar and to orientation of cross-like figure was studied by a temporal slices method in 87 neurons of the cat primary visual cortex. Tuning was plotted by spikes number in the entire response and in its successive fragments with a step of 20 ms. It was found that successive dynamic shift of preferred orientation of a bar was typical for 87% units, white such shift of preferred orientation of a cross was met in 75% of cases. Comparison of tuning dynamics for bar and cross allowed to separate units into three groups: the first one (58.6% of cases) with larger dynamic shift of a bar preferred orientation then of a cross (74.9 +/- 5.8 degrees [symbol: see text] 29.8 +/- 4.1 degrees, correspondingly, p < 0.00001), the second group (21.5%) with opposite effect (24.2 +/- 5.2 degrees and 69.2 +/- 10.0 degrees, p < 0.0002) and the third group (19.8%) without significant shift of preferred orientation of bar and cross and without difference in their dynamics. Possible mechanisms of the preferred orientation dynamics and its difference for bar and cross are discussed.

Action Potentials↗
PubMedDate not supplied

Community health orientation, community-based quality improvement, and health promotion services in hospitals.

The objective of the study presented in this article was to examine the relationship between hospital community orientation and the provision of health promotion services. The study used data from the 2000 American Hospital Association survey and the 2000 Area Resource File to examine acute care hospitals throughout the United States. The study was a cross-sectional multiple regression analysis. Hospital community orientation was measured by two independent variables: (1) community health orientation and (2) community-based quality orientation. Health promotion services were represented by two dependent variables: (1) hospital-based health promotion services and (2) collaborative health promotion services. Organizational control variables included bed-size code, not-for-profit ownership, network participation, and joint venture/alliance membership. Environmental control variables included the proportion of population over age 65, the percentage of population below the poverty level, the square root of the proportion of Medicaid inpatient revenue, the presence of state community benefit laws/guidelines, a Herfindahl-Hirschman Index of level of competition, and an index of managed care influence. Results of regression analyses showed that community health and community-based quality orientations were positively and significantly related to both the direct provision of health promotion services by hospitals and the collaborative provision of health promotion services through systems, joint ventures, and networks. The study concludes that a community health orientation and a community-based quality orientation lead to greater provision of health promotion services.

Community-Institutional Relations↗
PubMed2004

Root biomass and carbon storage in oriental spruce and beech stands in Artvin, Turkey.

In this study, influence of slope position (south-facing vs. north-facing), species type and sampling time on fine (0-2 mm), small (2-5 mm) and coarse (5-10 mm) root biomass and carbon storage of oriental spruce (Picea orientalis) and oriental beech (Fagus orientalis) were investigated. Mean total root biomass of oriental spruce was 20160 kg ha(-1) in south-facing slopes and 17140 kg ha(-1) in north-facing slopes. Mean total belowground C storage of oriental spruce was 7861 kg ha(-1) in south-facing slopes and 6840 kg ha(-1) in north-facing slopes. Similarly, biomass and C storage of oriental beech were 17190 and 6690 kg ha(-1) in south-facing slopes, and 13260 and 5200 kg ha(-1) in north-facing slopes, respectively. Oriental spruce had significantly higher fine root biomass than did oriental beech in south-facing slopes. Fine root biomass was significantly higher in fall than in spring in south-facing slopes.

Biomass↗
PubMed1990

Field orientation effects during 5.6-GHz radiofrequency irradiation of rats.

Ketamine-anesthetized Sprague-Dawley rats were exposed in E and H orientations (long axis parallel to electric and magnetic fields, respectively) to far-field 5.6-GHz continuous-wave radio-frequency radiation (RFR). Power densities were used that resulted in equivalent whole-body average specific absorption rates of 14 W/kg in both orientations (90 mW/cm2 for E and 66 mW/cm2 for H). Irradiation was conducted to increase colonic temperature by 1 degree C (from 38.5 to 39.5 degrees C). During experimentation, arterial blood pressure and respiratory rate and colonic, tympanic, left and right subcutaneous (sides toward and away from RFR source), and tail temperatures were continuously recorded. Results showed no significant difference in the times required to cause a 1 degree C increase or to recover to the initial temperature when irradiation was stopped. Significant differences between E- and H-orientation exposure were seen in the patterns of localized heating. The tail and left subcutaneous temperature increases were significantly greater during E-orientation exposure, the tympanic site showed no difference, and the right subcutaneous temperature increase was significantly greater during H-orientation exposure. Under both exposure conditions, heart rate and mean arterial blood pressure significantly increased during irradiation; however, there were no significant differences between E and H orientation responses. These findings at 5.6 GHz are in contrast to the significant cardiovascular response differences between E- and H-orientation exposure noted during a previous study of irradiation at 2.45 GHz.

Animals↗
PubMed1990

Ruptured aneurysms of the sinus of Valsalva in Oriental patients.

Between 1964 and 1987, a total of 57 cases of ruptured aneurysm of the sinus of Valsalva underwent surgical correction at the National Taiwan University Hospital. This represents 0.96% of all cardiac operations. The origin of ruptured aneurysm of the sinus of Valsalva was the right coronary sinus in 46, the noncoronary sinus in nine, and the left coronary sinus in two. The aneurysms ruptured into the right ventricle in 44, into the right atrium in 11, into the left ventricle in one, and into both the right ventricle and right atrium in one. Associated congenital cardiac anomalies included ventricular septal defect in 30 patients, aortic regurgitation in 20, and infundibular pulmonic stenosis and coarctation of the aorta in one each. Operative death occurred in two patients (3.5%) and one patient had a successful reoperation. The remainder did well following surgery. To compare the differences between Oriental and Western countries in ruptured aneurysm of the sinus of Valsalva, 361 cases (195 Oriental patients versus 166 Western) were collected from the literature. Analyses of these cases revealed that ruptured aneurysm of the sinus of Valsalva in Oriental patients compared with Western series is characterized by a higher incidence (5 times), more aneurysms originating from the right coronary sinus (87.9% versus 63.6%), more aneurysm rupturing into the right ventricle (84.2% versus 56.6%), a higher incidence of association with ventricular septal defect (mainly supracristal) (59.0% versus 34.6%), less incidence of association with other congenital cardiac abnormalities (4.1% versus 21.5%), very few instances of rupturing into cardiac chambers other than the right ventricle and right atrium, and less incidence of occurrence in the extremities of ages (the youngest was 7 years in Oriental patients versus 11 months in the Western series). In other words, ruptured aneurysm of the sinus of Valsalva in Oriental patients is more or less a simple and uniform disease entity in contrast to the more diverse and protean pathologic profiles encountered in Western series. However, both Oriental patient and Western patient series have similar incidences of combination with aortic regurgitation (24.6% versus 20.0%), with 40.4% of Oriental patients and 60.6% of Western patients presenting with intact ventricular septum. Therefore the pathogenetic mechanisms of ruptured aneurysm of the sinus of Valsalva may at the same time contribute to the development of aortic regurgitation.

Adolescent↗
PubMed1988

Strategic orientations of small multihospital systems.

Strategic behaviors of organizations can be classified along two dimensions--growth orientations, or patterns of evolution over time, and action orientations, or strategic aggressiveness in undertaking a particular growth orientation. We create measures of growth and action orientations for small multihospital systems and test the validity of the growth and action orientation typologies, using data from a sample of small multihospital systems. Growth and action orientations do appear to exist independently of each other, and they are related to the ownership status of the systems. Not-for-profit and church-other systems exhibit similar strategic orientations, unlike those of Catholic and investor-owned systems.

Data Collection↗
PubMed1987

Origin of orientation-selective EPSPs in simple cells of cat visual cortex.

According to current theory, orientation selectivity in cortical simple cells is critically dependent on intracortical synaptic inhibition. In particular, it is thought that IPSPs evoked by stimuli of the nonpreferred orientation are required to prevent a neuron from responding to a broadly tuned excitatory input at any but the preferred orientation. Yet EPSPs recorded in simple cells are in themselves highly orientation-selective. How is this possible, when excitation arises primarily from relay cells of the lateral geniculate nucleus (LGN), which are largely insensitive to orientation? In this paper, the properties of EPSPs are compared with the predictions of a model of geniculate excitation of simple cells. The model, which is derived from the suggestions of Hubel and Wiesel (1962), relies on the now familiar arrangement of the receptive fields of presynaptic geniculate cells into lines parallel to the axis of orientation of the postsynaptic cell. Several properties of the EPSPs observed in simple cells, and the orientation tuning of simple cells observed in extracellular experiments, can be accounted for without resorting to intracortical inhibition.

Animals↗
PubMed1978

Structure, synthesis and orientation of microfibrils. V. On the recovery of Oocystis solitaria from microtubule inhibitor treatment.

Depending on the type of the inhibitor and its concentration one can experimentally induce two forms of aberrant microfibril orientations in O. solitaria cell walls through microtubule inhibitor application. The first form, designated "Intermediate", is characterized by the presence of cortical microtubules together with a spiral arrangement of microfibrils. The second form, designated "Parrallel", shows a wall with bundles of parallel oriented microfibrils without cortical microtubules. Taking colchicine as an example for a microtubule-inhibitor the "Parallel" form may be obtained with 10mM and the "Intermediate" with 5 to 1 mM solutions. Some microtubule-inhibitors such as methylbenzimidazole-2yl-carbamate (MBC) produce the "intermediate" form only. The recovery of normal microfibril orientation after inhibitor treatment is dependent on three factors: a) the developmental stage--young autospores just beginning to synthesize a wall are absolutely necessary; b) the application of inhibitors with the lowest effective concentration for c) the shortest possible time. Minimal concentrations for obtaining a "Full" effect range from 10 mM for colchicine to 1 micrometer for amiprophosmethyl (APM) with incubation periods from 3 to 9 hours. The return to the normal microfibril orientation has been achieved in all cases except after podophyllotoxin treatment. Since APM has been claimed to act selectively on tubulin synthesis in Chlamydomonas it was decided to compare the effects of this compound with cycloheximide (10 microgram/ml) on the recovery of microfibril orientation after colchicine treatment. In both cases no orientation recovery is possible although in the case of cycloheximide, synthesis of cellulose is drastically inhibited. This cycloheximide inhibition is fully reversible. During cycloheximide, but not APM, inhibition cortical microtubules return; however, due to the inhibition of cellulose synthesis itself, they cannot exert their orienting influence.

Chlorophyta↗
PubMed1981

[Treatment of alcoholism. Study of the efficacy of 4 therapeutic orientations].

The present survey studies, in a group of 145 alcoholics from the National Institute on Alcoholism in Costa Rica, the effectiveness of four therapeutic orientations in alcoholism: behavioral, psychosocial, occupational and multiple. The survey was carried out in a harmless population of alcoholics, and it aims to work out and to test treatment designs suitable to the uncovered level or prevention respecting to alcoholism, the secondary one. Each one of the groups receiving the diverse treatments stayed as in-patient under similar conditions. The treatment had a two-week duration; once finished, the patient was discharged and continued with a one-year follow-up. The outcomes are the following: 1. Treatment. The occupational and behavior-oriented treatments present a five months abstinence period as an estimate average effectiveness. The psychosocial-oriented treatments reach a seven months abstinence period. Its major effectiveness is due to the specific action this orientation develops on the patients having the worst prognosis. The integration, in a treatment, of orientations corresponding to different theoretical frames can determine reciprocal inhibition phenomena among orientations and lower the general effectiveness level. 2. Diagnosis. The personalities defined as depressive and paranoiac according to their prevailing basic anxiety, and the presence or absence of a conjugal tie holds an estimate link with the abstinence the patient showed when he was discharged from treatment. The prognosis value of this characteristic disappears when it is then direct object of a therapeutic orientation (psychosocial) given that this characteristics are sensitive to changes by action in a specific treatment.

Alcoholism↗
PubMed1980

Embryonic axis orientation in the mouse and its correlation with blastocyst relationships to the uterus. Part 1. Relationships between 82 hours and 4 1/4 days.

Up until at least 7 1/4 days p.c., the orientation of all axes in the mouse conceptus, embryonic axis included, is directly correlated with two orientations of the 82 h blastocyst within the lumen. These two are: the almost horizontal position of the blastocyst's inner cell mass-abembryonic pole axis and the fixation of its abembryonic pole to either the right wall of the uterine horn (type-R orientation) or to the left (type-L orientation). At 88 h and at 4 1/4 and 6 3/4 - 7 1/4 days equal numbers of conceptuses are found in type R and L orientations. Axes of symmetry also are recognizable in some developmentally advanced 82 h blastocysts and in all older conceptuses. For example, when the inner cell mass-abembryonic axis has become vertically oriented within the lumen by 4 1/4 days, the inner cell mass is oblique to this axis. It is concluded that the 82 h blastocyst's orientation to the uterine walls and floor provides it with positional information used in the location of its axes.

Animals↗
PubMed1994

Studies of protein A and herpes simplex virus-1 induced Fc gamma-binding specificities. Different binding patterns for IgG3 from Caucasian and Oriental subjects.

Herpes simplex virus type 1 (HSV-1) expresses a receptor that binds the Fc portion of IgG. This HSV-1 Fc gamma-binding protein is, like protein A of Staphylococcus aureus, known to bind human IgG1, IgG2 and IgG4 but not IgG3 subclasses. However, IgG3 with the allotype Gm(s+)(t+), prominent in the Oriental population, reacts with protein A. This prompted us to investigate the reactivity of Oriental IgG3 monoclonal myeloma proteins of various allotypes with the HSV-1 Fc gamma-binding protein. Of seven Oriental IgG3 myeloma proteins with allotypes Gm(s+)(t+)(u-)(b+)(g-), Gm(s-)(t-)(u+)(b+)(g-) and Gm(s-)(t-)(u+)(b-)(g+), all reacted with the HSV-1 Fc gamma-binding protein. This was in contrast to negative reactions obtained with three IgG3 myeloma proteins of Caucasian origin with Gm(b+)(g-) or Gm(b-)(g+) phenotypes. The same binding pattern, i.e. binding of IgG3 of Oriental but not of Caucasian origin, was found with protein A. The binding of the monoclonal Oriental IgG3 proteins was again independent of the G3m phenotype. These findings support the concept that the HSV-1 Fc gamma-binding protein A have a similar binding site on the IgG molecule. All monoclonal IgG3 proteins derived from Oriental subjects with or without histidine at position 435 bound to HSV Fc gamma-binding protein. This suggests that Oriental IgG3 myeloma proteins with Gm(s-)(t-) phenotypes have additional critical amino acid residue substitutions important for HSV Fc gamma binding different from those already known.

Asian People↗
PubMed1993

Development of orientation selectivity in ferret visual cortex and effects of deprivation.

The orientation selectivity of cells in ferret primary visual cortex was studied during normal development and in animals deprived of vision or of visual cortical activity. In normal animals from the age when visual responses were first recorded (postnatal day 23) through postnatal week 5, only about 25% of cells showed orientation-selective responses. By postnatal week 7, cortical responses had matured to an adult-like state, with approximately 75% of cells clearly selective for orientation. This development of orientation selectivity was not merely a reflection of the development of cortical cell responsiveness: at all ages studied, there was no correlation between responsiveness and selectivity. Infusion of TTX into visual cortex to silence neuronal activity completely blocked the maturation of orientation selectivity. Visual deprivation by bilateral lid suture impaired but did not completely block the normal development of orientation selectivity. We conclude that the maturation of orientation-selective responses in ferret primary visual cortex requires cortical neuronal activity, and that normal development requires visually driven activity.

Animals↗
PubMed1994

A model for the development of simple cell receptive fields and the ordered arrangement of orientation columns through activity-dependent competition between ON- and OFF-center inputs.

Neurons in the primary visual cortex of higher mammals respond selectively to light/dark borders of a particular orientation. The receptive fields of simple cells, a type of orientation-selective cell, consist of adjacent, oriented regions alternately receiving ON-center and OFF-center excitatory input. I show that this segregation of inputs within receptive fields can occur through an activity-dependent competition between ON-center and OFF-center inputs, just as segregation of inputs between different postsynaptic cells into ocular dominance columns appears to occur through activity-dependent competition between left-eye and right-eye inputs. These different outcomes are proposed to result, not from different mechanisms, but from different spatial structures of the correlations in neural activity among the competing inputs in each case. Simple cells result if ON-center inputs are best correlated with other ON-center inputs, and OFF with OFF, at small retinotopic separations, but ON-center inputs are best correlated with OFF-center inputs at larger separations. This hypothesis leads robustly to development of simple cell receptive fields selective for orientation and spatial frequency, and to the continuous and periodic arrangement of preferred orientation across the cortex. Input correlations determine the mean preferred spatial frequency and degree of orientation selectivity. Estimates of these correlations based on measurements in adult cat retina (Mastronarde, 1983a,b) produce quantitative predictions for the mean preferred spatial frequencies of cat simple cells across eccentricities that agree with experiments (Movshon et al., 1978b). Intracortical interactions are the primary determinant of cortical organization. Simple cell spatial phases can play a key role in this organization, so arrangements of spatial phases and preferred orientations may need to be studied together to understand either alone. Possible origins for other cortical features including spatial frequency clusters, afferent ON/OFF segregation, blobs, pinwheels, and opponent inhibition within simple cell receptive fields are suggested. A number of strong experimental tests of the hypothesis are proposed.

Algorithms↗
PubMed1996

Functional organization for direction of motion and its relationship to orientation maps in cat area 18.

The goal of this study was to explore the functional organization of direction of motion in cat area 18. Optical imaging was used to record the activity of populations of neurons. We found a patchy distribution of cortical regions exhibiting preference for one direction over the opposite direction of motion. The degree of clustering according to preference of direction was two to four times smaller than that observed for orientation. In general, direction preference changed smoothly along the cortical surface; however, discontinuities in the direction maps were observed. These discontinuities formed lines that separated pairs of patches with preference for opposite directions. The functional maps for direction and for orientation preference were closely related; typically, an iso-orientation patch was divided into regions that exhibited preference for opposite directions, orthogonal to the orientation. In addition, the lines of discontinuity within the direction map often connected points of singularity in the orientation map. Although the organization of both domains was related, the direction and the orientation selective responses were separable; whereas the selective response according to direction of motion was nearly independent of the length of bars used for visual stimulation, the selective response to orientation decreased significantly with decreasing length of the bars. Extensive single and multiunit electrical recordings, targeted to selected domains of the functional maps, confirmed the features revealed by optical imaging. We conclude that significant processing of direction of motion is performed early in the cat visual pathway.

Age Factors↗
PubMed2003

Orientation and mobility training for adults with low vision.

BACKGROUND: Orientation and mobility (O&M) training is provided to people who are visually impaired to help them maintain travel independence, teaching them new orientation and mobility skills to compensate for reduced visual information. OBJECTIVES: The objective of this review was to assess the effects of orientation and mobility training, with or without associated devices, for adults with low vision. SEARCH STRATEGY: We searched the Cochrane Central Register of Controlled Trials - CENTRAL (which contains the Cochrane Eyes and Vision Group trials register) (Issue 3 2002), MEDLINE (1966 to August 2002), EMBASE (1980 to September 2002) and LILACS (September 2002) and the reference lists of articles. SELECTION CRITERIA: We planned to include randomised or quasi-randomised trials comparing orientation and mobility training with no training in adults with low vision. DATA COLLECTION AND ANALYSIS: Two reviewers independently assessed the search results for eligibility. MAIN RESULTS: No studies were found that satisfied the inclusion criteria. REVIEWER'S CONCLUSIONS: We could not find any controlled trials on the effects of orientation and mobility training for adults with low vision. As a premise to future trials, orientation and mobility instructors and scientists should reach a consensus and develop valid measures of mobility performance which are both reliable and meaningful to people with low vision.

Adult↗
PubMed2001

Orientation of bull sperms in static magnetic fields.

The orientation of bull sperm cells in static magnetic fields was investigated by microscopic observation. The bull sperm, which has a very flat head, was fixed and its motion was stopped by glutaraldehyde. It was oriented with the whole body and the flat head perpendicular to the direction of the magnetic field. The diamagnetic cell components, such as the cell membrane, the DNA in the head, and the microtubule in the tail, were thought to contribute to this orientation, because bull sperm does not have paramagnetic components. For quantitative measurement of the orientation, the intensity of transmitted light through glutaraldehyde-fixed bull sperm suspension in a photometric cell was determined. The intensity changed slightly in proportion to the mean degree of orientation of the sperms. It increased sigmoidally depending on the intensity of the magnetic field and reached 100% at just below 1 T. The magnetic orientation is very strong in comparison to that of erythrocytes or platelets. By studying the response of the bull sperm to the magnetic field, it will be possible to understand its microstructure in more detail.

Animals↗
PubMed2001

Axonal topography of cortical basket cells in relation to orientation, direction, and ocular dominance maps.

The axonal (bouton) distributions of a layer 4 clutch cell (CC), two layer 3 medium-sized basket cells (MBC), and a layer 3 large basket cell (LBC) to orientation, direction, and ocular dominance maps were studied quantitatively. 1) The CC provided exclusively local projections (<380 microm from the soma) and contacted a narrow "niche" of functional representations. 2) The two MBCs emitted local projections (75% and 79% of all boutons), which were engaged with isoorientations (61% and 48%) and isodirections, and long-range projections (25% and 21%, >313 microm and >418 microm), which encountered cross-orientation sites (14% and 12%) and isoorientation sites (7% and 5%). Their direction preferences were mainly perpendicular to or opposite those of local projections. 3) The LBC provided the majority (60%) of its boutons to long-range distances (>437 microm). Locally, LBC boutons showed a rather balanced contribution to isoorientations (19%) and cross-orientations (12%) and preferred isodirections. Remotely, however, cross-orientation sites were preferred (31% vs. 23%) and the directional output was balanced. 4) Monte Carlo simulations revealed that the differences between the orientation specificity of local and long-range projections cannot be explained by a homogeneous lateral distribution of the boutons. 5) There was a similar eye preference in the local and long-range projection fields of the MBCs. The LBC contacted both contra- and ipsilateral eye domains. 6) The basket axons showed little laminar difference in orientation and direction topography. The results suggest that an individual basket cell can mediate a wide range of effects depending on the size and termination pattern of the axonal field.

Animals↗
PubMed1980

Topographic organization of the orientation column system in the striate cortex of the tree shrew (Tupaia glis). II. Deoxyglucose mapping.

The topographic organization of the orientation column system in the tree shrew striate cortex was examined by using 2-deoxyglucose autoradiography to map the cortical sites of increased metabolic activity produced by visual stimulation with stripes of a single orientation. Awake experimental tree shrews (freely moving, restrained, or paralyzed) were given injections of deoxyglucose label and then stimulated with vertical, horizontal, or oblique stripes for 45--75 min. Autoradiographs of coronal sections through the striate cortex revealed regularly spaced radial zones of increased deoxyglucose uptake 150--350 micrometers wide, extending from the cortical surface to the white matter, separated by interzone regions of lower uptake. The radial zones were most densely labeled and distinct in layers I--IIIb and least distinct in layer IV, which was continuously and densely labeled throughout both the radial zone and interzone regions. These radial zones, which were not present in control animals that viewed many orientations, reflect the locations of cortical cells activated by a single stimulus orientation. Reconstructions of the radial zones from serial sections produced maps of the distribution of increased deoxyglucose uptake across striate cortex. The maps reveal a highly organized system of narrow, parallel bands that are slightly wavy and have a mean spacing of 530 micrometers. The band pattern was confirmed in sections cut tangential to the cortical surface and was similar in animals stimulated with either vertical or horizontal stripes; the bands consistently abut the 17--18 border at nearly right angles and extend across the striate cortex in a generally posteromedial direction. These patterns of increased deoxyglucose consumption confirm the anisotropic distribution of orientation-selective cells across the tree shrew striate cortex, suggested in the preceding microelectrode study (Humphrey and Norton, '80). The density distribution of label within the bands further suggests that the anisotropy is due to a system of parallel, somewhat wavy iso-orientation lines arranged roughly perpendicular to the 17--18 border.

Animals↗