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PubMed1990

Relation of spatial reasoning ability to hand performance in male and female left-handers to familial sinistrality and writing hand.

The relation of mental ability for spatial reasoning to hand performance was studied in male and female left-handers considering familial sinistrality and writing hand. Hand performance was assessed by a dot-filling test; hand preference was assessed by the Edinburgh Handedness Inventory (Geschwind scores). Nonverbal intelligence (spatial reasoning) was measured by the Cattell's Culture Fair Intelligence Test. The relationship between IQ and hand performance was found to be more complicated than expected. This was associated with sex, familial sinistrality, and writing hand, which created different patterns in interactions between motor and cognitive systems. It was concluded that the brain benefits from different strategies by using both hemispheres in a competitive and complementary manner where necessary to achieve a high visual-spatial performance depending upon genetic preprograms.

Adult↗
PubMed1990

Relationship of testosterone and nonverbal intelligence to hand preference and hand skill in right-handed young adults.

The relationship between serum testosterone level and nonverbal intelligence was studied in right-handed young adults with regard to handedness. Hand preference was assessed by the Edinburgh Handedness Inventory. Hand skill was measured by a peg moving task. Serum testosterone level was determined using tritium-marked-radioimmunoassay. Visual-spatial performance (nonverbal intelligence) was measured by Cattell's Culture Fair Intelligence Test. In men with consistent right-hand preference (GSs: 80 to 100), IQ was found to be positively linearly related to serum testosterone, which exhibited two regression lines belonging to low and high difference in skill between hands. In females with consistent right-handedness, there was a negative linear correlation between IQ and serum testosterone, which also exhibited two different regression lines according to difference in skill between hands. In males with moderate right-hand preference (GSs 50 to 75), IQ was found to be positively linearly related to serum testosterone, exhibiting two different (same slopes) regression lines according to difference in skill between hands. In females with moderate right-hand preference, IQ first increased and then decreased with serum testosterone, exhibiting a quadratic relationship. These results suggested that serum testosterone in young adults may be associated with visual-spatial performance depending upon sex, hand preference, and hand skill.

Adolescent↗
PubMedDate not supplied

Ultrastructure of in situ hybridization.

Techniques for the ultrastructural localization of structures identified by in situ hybridization are being developed for both preembedding labeling and labeling on thin sections (postembedding). Successful labeling of both RNA and DNA sequences has been reported in recent years. Biotinylated nucleic acid probes are becoming increasing available. Colloidal gold is the only successful ultrastructural label with meaningful spatial localization, and the best results have been obtained with small (20-5 nm) gold particles. The link between biotinylated nucleic acid probes and gold has been protein A, antibiotin, or avidin binding. The size of the target nucleotide sequence, the size of the probe, and the number of gold particles attached to the labeling protein must be understood before there can be meaningful interpretation of micrographs. In addition, the spatial considerations depend on whether preembedding or postembedding is used.

DNA, Viral↗
PubMed1996

A comparison of binocular summation in young and older patients.

Binocular and monocular contrast sensitivities were measured at two spatial frequencies of 1 and 6 c/deg in 8 young (mean age 22.6 +/- 3.8 years) and 18 older subjects with normal healthy eyes (mean age 58.4 +/- 7.3 years). Data were analysed as binocular summation ratios defined as binocular CS/"best eye' CS. Binocular summation ratios were higher for the younger group (1.46 and 1.48 for 1 and 6 c/deg respectively) compared to the older group who demonstrated a spatial frequency dependence (1.31 and 1.13 at 1 c/deg and 6 c/deg respectively). The results are discussed in terms of age-related cortical cell loss and increased monocular sensitivity differences between the two eyes.

Adult↗
PubMed2000

Tactile perception in blind Braille readers: a psychophysical study of acuity and hyperacuity using gratings and dot patterns.

It is not clear whether the blind are generally superior to the sighted on measures of tactile sensitivity or whether they excel only on certain tests owing to the specifics of their tactile experience. We compared the discrimination performance of blind Braille readers and age-matched sighted subjects on three tactile tasks using precisely specified stimuli. Initially, the blind significantly outperformed the sighted at a hyperacuity task using Braille-like dot patterns, although, with practice, both groups performed equally well. On two other tasks, hyperacute discrimination of gratings that differed in ridge width and spatial-acuity-dependent discrimination of grating orientation, the performance of the blind did not differ significantly from that of sighted subjects. These results probably reflect the specificity of perceptual learning due to Braille-reading experience.

Adult↗
PubMed2000

Color-luminance relationships and the McCollough effect.

The McCollough effect is an orientation-specific color aftereffect induced by adapting to colored gratings. We examined how the McCollough effect depends on the relationships between color and luminance within the inducing and test gratings and compared the aftereffects to the color changes predicted from selective adaptation to different color-luminance combinations. Our results suggest that the important contingency underlying the McCollough effect is between orientation and color-luminance direction and are consistent with sensitivity changes within mechanisms tuned to specific color-luminance directions. Aftereffects are similar in magnitude for adapting color pairs that differ only in S cone excitation or L and M cone excitation, and they have a similar dependence on spatial frequency. In particular, orientation-specific aftereffects are induced for S cone colors even when the grating frequencies are above the S cone resolution limit. Thus, the McCollough effect persists even when different cone classes encode the orientation and color of the gratings.

Color Perception↗
PubMed2000

Spatial relationship between vestibular schwannoma and facial nerve on three-dimensional T2-weighted fast spin-echo MR images.

BACKGROUND AND PURPOSE: During surgical removal of a vestibular schwannoma, correct identification of the facial nerve is necessary for its preservation and continuing function. We prospectively analyzed the spatial relationship between vestibular schwannomas and the facial nerve using 3D T2-weighted and postcontrast T1-weighted spin-echo (SE) MR imaging. METHODS: Twenty-two patients with a unilateral vestibular schwannoma were examined with MR imaging. The position and spatial relationship of the facial nerve to adjacent tumor within the internal auditory canal (IAC) and cerebellopontine angle cistern (CPA) were assessed on multiplanar reformatted 3D T2-weighted fast spin-echo (FSE) images and on postcontrast transverse and coronal T1-weighted SE images. The entrance of the nerve into the bony canal at the meatal foramen and the nerve root exit zone along the brain stem were used as landmarks to follow the nerve course proximally and distally on all images. RESULTS: The spatial relationship between vestibular schwannoma and facial nerve could not be detected on postcontrast T1-weighted SE images. In 86% of the patients, the position of the nerve in relation to the tumor was discernible on multiplanar reformatted 3D T2-weighted FSE images. In tumors with a maximal diameter up to 10 mm, the entire nerve course was visible; in tumors with a diameter of 11 to 24 mm, only segments of the facial nerve were visible; and in tumors larger than 25 mm, the facial nerve could not be seen, owing to focal nerve thinning and obliteration of landmarks within the IAC and CPA. CONCLUSION: Identification of the facial nerve and its position relative to an adjacent vestibular schwannoma is possible on multiplanar reformatted 3D T2-weighted FSE images but not on postcontrast T1-weighted SE images. Detection of this spatial relationship depends on the tumor's size and location.

Adult↗
PubMed1996

[History and demographic systems].

Is it possible to describe the past evolution of populations by using the notion of system? This article shows that three obstacles arise: the disciplinary stricture, that is, the artificial isolation of demographic phenomena cut off from the political and economic phenomena on which they depend; the spatial stricture, that is, the delimitation of a given zone, quite often a village or small town, which means excluding readjustments, by migration; and, finally, the confusion of scales, that is, the passing from an individual level ("micro") to a collective one ("macro"). Given these obstacles, the few systems proposed are severely limited. An example of this limitation is given with the model called self-regulating, which is disturbed when mortality diminishes. Hence, we propose a more modest vision of demographic systems.

History, 20th Century↗
PubMed2002

[Quantitative analysis of landscape conditions of the desertified sandy grassland in Ordos Plateau].

The landscape condition of the sandy grassland in southeast of Ordos Plateau was analyzed based on the data from field investigation along two intercepting 5 km transects. Summary on frequency of the patches showed that small-scale patches were prominent in this area, with 95% of total patches smaller than 50 m and average dimension of patches 15 m, while there were also a couple of large-scale mobile sandy patches. Environmental heterogeneity dependent on spatial scales was revealed by semivarogram in the sampling area. The large fractal dimensions of percent coverage of bare ground, close to 2, indicated dominant small-scale spatial variance. This result implies a relative stabilized landscape and also a desertified area.

China↗
PubMed2002

Vulnerability of groundwater to pollution from agricultural diffuse sources: a case study.

Kumluca, near Antalya in Turkey, is an important plain with its intensive agricultural activities employing greenhouses. The chemical fertilizer application practices caused excessive increases of the nitrogen, phosphorus and salinity within groundwater. A study has been initiated to assess the present state of the groundwater pollution problem of Kumluca Plain. A total of nine measurement and sampling stations have been selected to represent different depths groundwater table, different types of agricultural activities and different soil types. The magnitudes of the parameters: temperature, salinity and conductivity, nitrate, nitrite, ammonia, orthophosphate and fecal coliform were determined for groundwater. Soil samples collected from the stations have been analyzed for several parameters such as texture, total salinity, total nitrogen, and total phosphorus. The measurement and analyses results of the groundwater showed wide spatial variations depending on factors such as the quality of irrigation water, depth groundwater, soil characteristics, type and age of agriculture and hydrology. Groundwater vulnerabilities to pollution have been analyzed using the SEEPAGE Model approach. Furthermore the soil, aquifer and groundwater characteristics, which will be utilized to establish "cause" and "effect" relationships in future, have been clarified.

Agriculture↗
PubMed2004

In vivo imaging of the rat cerebral microvessels with optical coherence tomography.

A technique called optical coherence tomography (OCT) was applied to in vivo observation of microcirculation in the rat cerebral cortex. The OCT system used in this study provided cross-sectional images of the cerebral cortical tissue up to about 1 mm depth with longitudinal resolution up to 8 microm. It could visualize cross-sectional structure of the dura, arachnoid membrane, cortical tissue, and pial microvessels through the cranial window. Pial microvessels with diameter larger than several 10 microm could be detected to observe their cross-sectional shape, while the microvessels within the cortical tissue with smaller diameter were not discernible. The OCT observation revealed that the pial microvessels showed different spatial configurations depending on the cerebral preparations with intact dura and without dura. Stimulus responses of the somatosensory cortices were also different among the preparation methods; Delayed swelling of the cortical surface appeared in the somatosensory cortex following the electrical stimulation of the hind paw in the case of dura removal, which was restricted to a thin surface layer with less than several 10 microm. It is considered to reflect the reactive hyperemia accompanying the neuronal activation. Doppler frequency shift due to the blood flow was detected in pial arterioles. This phenomenon is promising to provide the velocity profile within microvessels and may be applicable to the functional imaging of the brain.

Animals↗
PubMed1992

[Digital image intensifier radiography--what dose for what clinical problem?].

Due to a wide dynamic range it is possible to vary the dose of DIIR for each type of examination according to the required image quality. To define the possible decrease of dose compared to film-screen radiography (speed 200) the dependence of spatial resolution and contrast detectability upon dose was evaluated. We used a Polytron 1000 which was connected to a Siregraph D and an Optilux 57 (Siemens). Acquisition parameters were fixed for different types of examination and tested by imaging anthropomorphic phantoms as well as patients (n = 114). Our results demonstrate that the dose can be reduced by 60% for double-contrast examinations and by 85% for mono-contrast studies. Although DIIR is less suited for chest and skeletal imaging, a 14 cm image intensifier can be used for imaging small lesions. If poor image quality is acceptable (e. g. pelvimetry, sometimes in paediatrics), a maximum reduction of 95% is possible.

Humans↗
PubMed2005

[Theoretical considerations for evaluating the degree of random-periodicity of graphic noise.].

Graphic noise properties are usually evaluated using the Wiener spectrum. However, this approach is not appropriate for periodic noise for two reasons. One is that it takes infinite values at the spatial frequencies of periodic noise. The other is that when adopting a numerical integration, it allows unstable values at each spatial frequency, depending on the integral region. Introducing three types of spectra (W(1), W(2), and W(3)) in connection with the Wiener spectrum, we propose a practical approach to evaluation of periodic noise. Graphic images sometimes contain noise that is not totally random and not perfectly periodic. Therefore, using the Wiener spectrum and the W(1) spectrum, we also propose two factors for evaluation of the degree of random-periodicity of noise containing periodic signals.

Humans↗
PubMed2006

[Dynamic of DNA-binding activity of transcription factors in A431 cells during their spreading on immobilized ligands].

Dynamics of actin cytoskeleton in A431 cells and specific NF-kappaB SRF and AP-1 DNA-binding activities were studied during a 2 h spreading of these cells on fibronectin, laminin-2/4 or an antibody to epidermal growth factor receptor. Cell spreading was shown to be accompanied by sequential formation of actin cytoskeleton structures, whose spatial organization depends on the type of immobilized ligand. We have determined the time intervals, within which certain forms of cytoskeleton do not change qualitatively and are specific for dominant part of cell population. It has been shown that DNA-binding activities of the above transcription factors studied oscillate during cell spreading. The cycles of DNA-binding activity were found to be equel to 15-40 min. The character of oscillations depends on both transcription factor and ligand type. The temporal comparison of presses of actin cytoskeleton formation and DNA-binding activity of NF-kappaB and SRF times suggest that actin cytoskeleton reorganization may be presumably associated with activation of NF-KppaB and SRF.

Actins↗
PubMed1990

[A color after-effect: the McCollough effect].

Coloured after-effect parameters have already been studied but the process involved in these events remains unknown. In the case of the McCollough effect, Shute has shown that the induced colour decreases rapidly at first and then more slowly. In a normal subject the effect can no longer be detected after approximately 2 hours. Results have been used to determine a relationship between the purity of the induced colour and time: I = I0 e-bt, where b is a typical parameter of the subject related to his physiological state. A figure of b approximately 0.03 min-1 was obtained in the normal subject. The rate of decay is influenced by certain drugs. In particular, a greater decrease in induced colour is obtained when caffeine is taken. In this case, the value of the decay constant b is about 0.06 min-1. Results obtained with anticholinergic agents are contrasted with those obtained with caffeine: slowed decay occurs. Hence the value of the decay constant is about 0.01 min-1. Data show that the McCollough effect could be an inhibitory mechanism in a visual pathway and which tends to suppress neural connections. It should be noted that the geometrical structures of patterns play an important part in the perception of the induced colour. For example, with square-wave gratings, the strength of the induced colour depends on spatial frequency and orientation. The McCollough effect mainly concerns the ways in which we perceive both pattern and colour. It may be located either within the retina or more centrally in the visual system.

Color Perception↗
PubMed1989

[Interrelation of conformational changes of crustacin and its capacity to bind specifically with carcino-embryonic antigen].

Temperature-, ionic strength-, calcium ion- and pH-dependence of spatial structure of crustacin have been studied using CD and fluorescent spectroscopy. Secondary structure of crustacin was estimated by CD spectra. An irreversible conformational transition of crustacin's protein moiety connected with the loss of CEA-binding activity has been found at ca. 50 degrees C. Crustacin is shown to be calcium-binding protein, stability of the native crustacin conformation being markedly enhanced by calcium ions (1 mM Ca2+ shifted up the transition temperature by approximately 10 degrees C). Calcium binding and ionic strength increase led to alteration of both secondary and tertiary structures of crustacin. The highest CEA-binding activity was observed for the calcium-bond form of crustacin. A lack of specific interaction of crustacin with some saccharides was shown. Interrelation between conformation and immunochemical activity of crustacin is discussed.

Calcium↗
PubMedDate not supplied

[Temporal organization of interneuronal relations in the cerebral cortex of the cat in relation to the level of alimentary motivation].

By means of records of multicellular activity, interneuronal relations and their modifications in two cortical zones (Visual and motor) were studied in cats at different levels of alimentary motivation. For quantitative evaluation of interneuronal relations the statistic method of cross-correlation analysis of impulse trains was used in determining the probability of the appearance of the discharge of one neurone after the impulse of the other one. For groups of neurones in both investigated cortical areas, three-neurones microsystems were singled out and their activity was analyzed by temporal parameters of interaction between neurones at the interval of 120 ms, both within one microarea (intraanalyzer connections) and between microareas of two cortical zones. The correlation of temporal parameters of interneuronal connections (temporal delays in the activity of neuronal pairs) changed depending on spatial localization of neurones and functional condition of the animals. The existence is suggested of "informational" (1-30 ms) and "motivational" (90-120 ms) values of interneuronal relations for interanalyser connections.

Animals↗