The influence of cortical feature maps on the encoding of the orientation of a short line

The inhomogeneous distribution of the receptive fields of cortical neurons influences the cortical representation of the orientation of short lines seen in visual images. We construct a model of the response of populations of neurons in the human primary visual cortex by combining realistic response properties of individual neurons and cortical maps of orientation and location preferences. The encoding error, which characterizes the difference between the parameters of a visual stimulus and their cortical representation, is calculated using Fisher information as the square root of the variance of a statistically efficient estimator. The error of encoding orientation varies considerably with the location and orientation of the short line stimulus as modulated by the underlying orientation preference map. The average encoding error depends only weakly on the structure of the orientation preference map and is much smaller than the human error of estimating orientation measured psychophysically. From this comparison we conclude that the actual mechanism of orientation perception does not make efficient use of all the information available in the neuronal responses and that it is the decoding of visual information from neuronal responses that limits psychophysical performance.

Determination of the Pu240/Pu239 ratio by alpha spectrometry using the WinALPHA program

The isotopic ratio of 240Pu to 239Pu is an important parameter in identifying the origin of plutonium in a given radioactive sample. High-resolution mass spectrometry is generally accepted as an accurate technique for determining this ratio, but this is a very costly method. Alternatives to this method are alpha- and gamma-spectrometry studies but the problem with these low-cost method lies with the analysis of the spectrum. Recently, Noy et al. [2004. Nucl. Instrum. Methods in Phys. Res. A 525, 522-528] developed a computer program code called WinALPHA to quantitatively analyze the alpha spectrum; the program is available from the IAEA website. In this paper, we report the results obtained from the analysis of the alpha spectrum of plutonium from power bearing product samples from power reactor fuel reprocessing plant using the WinALPHA program. The results are found to be in good agreement (within 1-2%) with results from mass spectrometry.

Illusory motion in Enigma: a psychophysical investigation

Experiments to determine the optimum conditions for perceiving illusory motion in Engima-like patterns have also demonstrated that the illusory motion is not the result of unintended motion of the image on the retina due to microsaccades or accommodative changes in the lens of the eye but instead has a cortical origin. The perceived illusory activity is believed to be a consequence of neural signals emanating from high-contrast bars and edges in the image that emit randomly fluctuating signals, as expected from spiking cortical neurons. These fluctuations may induce illusory motion in the channels by a mechanism similar to that responsible for the Omega effect, in which sequences of random patterns of black dots presented in an annular channel produce the perception of illusory rotation of these dots within the annulus.

A girl with abnormal head and eye movements: Joubert syndrome (2005:3b)

We describe a mentally retarded patient with developmental delay, abnormal head and eye movements with suspected blindness and episodes of abnormal breathing. Subsequent CT and MRI were performed to reach to the final diagnosis. The clinical history and the imaging findings were classical for Joubert syndrome.

Hypolipidemic effect of Coriandrum sativum L. in triton-induced hyperlipidemic rats

In the biphasic model of triton-induced hyperlipidemia, C. sativum at a dose of 1g/kg body weight reduced cholesterol and triglycerides levels in both synthesis and excretory phases in rats, and the results were comparable with that of Liponil, a commercially available herbal hypolipidemic drug. The results suggest that coriander decreases the uptake and enhances the breakdown of lipids. From the study it can be assumed that coriander has the potential to be popularized as a household herbal remedy with preventive and curative effect against hyperlipidemia.

Biochemical evaluation of multiple herbal treatments in alloxan-induced diabetes in Wistar rats

Alloxan-induced diabetic rats were treated with multiple herbal preparation besides a control group receiving distilled water. The levels of glucose and alkaline phosphatase (ALP) increased abnormally in the alloxan treated group and the same were normalized upon treatment with the herbal preparation. The levels of blood urea nitrogen (BUN), alanine aminotransferase (ALT), protein and albumin in all groups remained unaltered. However, weekly body weight gain which got significantly altered in the alloxan-treated group was normalized by treatment with the herbal preparation. On the whole, a profound hypoglycemic effect was observed by the multiple herbal treatment in the diabetic rats.

Allele frequencies of apolipoprotein E gene polymorphisms in the protein coding region and promoter region (-491A/T) in a healthy Norwegian population

This study examines the distribution of apolipoprotein E (APOE) alleles in a population of healthy male and female Norwegians (n = 798) below the age of 40. The -491A/T polymorphism of the promoter region of the APOE gene was also examined. A seminested polymerase chain reaction was applied in the genotyping. The results showed that the E3 allele had the highest frequency (0.744), followed by E4 (0.198) and E2 (0.058). The APOE frequencies found in this study differ significantly from those obtained in earlier Norwegian APOE phenotypings. The allele frequencies in the -491 site of the promoter region were 0.845 for the A allele and 0.155 for the T allele. The genotype frequency was highest for AA (0.707), followed by AT (0.277) and TT (0.016). Moreover, the A allele was in linkage disequilibrium to E4.

Detection of isolated tumor cells in bone marrow in early-stage breast carcinoma patients: comparison with preoperative clinical parameters and primary tumor characteristics

PURPOSE/EXPERIMENTAL DESIGN: The importance of detection of disseminated isolated tumor cells (ITCs) in bone marrow (BM) is still not settled. BM aspirates from 920 patients with primary breast cancer were analyzed for tumor cells by standardized direct immunocytochemical analysis (ICC) of 2 x 10(6) mononuclear cells (MNCs) using anticytokeratin monoclonal antibody (AE1/AE3). Samples (637) were analyzed by negative immunomagnetic enrichment (IMS) followed by ICC (10 x 10(6) MNCs). Analyses of the primary tumor specimens have been performed, including histomorphology, tumor-node-metastasis (TNM) staging, grading, and immunohistochemical analyses.

RESULTS

Of the patients with infiltrating carcinoma, 63% were node negative (N0) and 33%, node positive (N+). The results show the presence of tumor cells in 13.4% of the evaluable patients after direct ICC analysis. The presence of tumor cells correlated to the nodal- and tumor stage, showing BM positivity in 9.9% of the N0 cases and 20.6% in the N+ group (P < 0.0005), 11.2% of the stage T(1) were positive, and 15.0% and 22.6% were positive in the T(2) and T(3/4) groups, respectively (P = 0.013). No correlation between detection of ITC and detection of p53 and cathepsin D expression was found. Vascular invasion and c-erbB2 expression were associated with ITCs in BM (P = 0.045 and P = 0.024, respectively). Node-negative patients with estrogen receptor (ER)+ and/or progesterone receptor (PgR)+ tumors had lower frequency of ITCs than ER-/PgR- (P = 0.004). The use of negative IMS increased the frequency of positive BM by 63% (P < 0.0005).

CONCLUSIONS

The direct ICC detection of ITCs in BM correlated with primary tumor stage, nodal stage, vascular invasion, c-erbB2 expression, and ER/PgR status. Analysis of larger BM samples by negative IMS resulted in increased number of ITC-positive patients.

Neurocysticercosis like presentation in a case of CNS tuberculosis

A clinical picture consisting of seizures, multiple non-tender subcutaneous nodules, and multiple 'nodular or ring' enhancing lesions in computed tomography of the brain is considered characteristic of neurocysticercosis in an endemic area. 1,2 A case with a similar clinical picture, in whom serological tests and histopathological examination of subcutaneous nodule established tuberculosis as a cause, is presented.

A simple method for removal of a broken intramedullary nail

The removal of broken implanted intramedullary nails secondary to re-fracture or non-union is challenging. In 12 cases a simple and safe method has been used to remove broken implants.

Familial myelodysplastic syndrome with early age of onset

A family is described in which three members, the propositus, his brother, and son, developed a myelodysplastic syndrome (MDS) at the ages of 52, 35, and 25, respectively. A fourth member, the paternal uncle of the propositus, was diagnosed with chronic lymphocytic leukemia. Two of the three affected Individuals had megaloblastoid marrows with recognizable bone marrow cytogenetic abnormalities and progressive, nonleukemic bone marrow failure. The propositus was unresponsive to G-CSF and eventually died of sepsis. The second affected family member died of bone marrow transplant complications. The third affected family member underwent bone marrow transplantation and is showing signs of graft survival despite minor complications. The affected members of this pedigree appear to represent a continuum in severity of disease and, therefore, pathogenesis. The pattern of inheritance and clinical progression of the disease suggest a genetic defect which may predispose individuals to the development of MDS.

Multiple matching of features in simple stereograms

Simple stereograms are used to show that the binocular matching of closely spaced vertical lines can be changed by horizontally connecting some of the vertical lines. The matching that is seen can be gradually changed by incremental modifications to simple visual quantities like the luminance contrast of a local region, or the density of the connecting horizontal lines. For some values of these visual quantities the depth seen is unstable which suggests that the mechanisms responsible for resolving matching ambiguities might be intrinsically dynamic. These changes in binocular matching can also be used to show a hysteresis-like effect in stereopsis. Many of the constraints like ordering, cohesivity, and uniqueness often used in algorithms for resolving ambiguities are perhaps too limiting to allow either such dynamics or the processing of transparent or partially occluded surfaces.