Macaque striate cortex: pattern, movement and colour processing

Simple cells in the primate visual cortex provide a form of generalized, pre-cognitive mapping of visual scenes. One point in space is represented by several orientation-specific cells capable of signalling both standing contrast and contrast changes in the scene. The arrangement of simple receptive fields (with a few antagonistic subregions) suggest analysis of scenes both in terms of symmetrical and antisymmetrical spatial components (i.e. lines and edges) and spatial-frequency contents. There is no evidence that this analysis is carried out within fixed areas (or patches) since a diversity of receptive field sizes was observed. A chromatic content is probably analysed by a different class of cells with concentric, cone-opponent receptive fields.     

An improved simple tungsten microelectrode

An improvement to tungsten-in-glass microelectrode has been made which requires no special skills. It involves the introduction of a gel solution into the glass micropipette which surrounds and binds the tungsten wire along its full length. A significant damping of microphonic effects is produced and a good fit between tungsten and glass near their tips becomes less critical for success. The electrode was found to be very stable over long recording sessions.     

Space and spatial frequency: analysis and representation in the macaque striate cortex

Summary Simple cells in the macaque striate cortex were tested with bars, edges and gratings. Spatial frequency tuning curves could be predicted from the spatial profiles plotted with bars and edges and the bandwidth could be evaluated more accurately by computing the mean from measured and predicted tuning curves. The results suggest that the mean relative spatial frequency bandwidth (f/fo) is nearly constant and of a moderate value. But at each optimal spatial frequency, cells with different bandwidths (about a factor of two) were recorded. The shapes of spatial response profiles resemble the corresponding spatial and spatial frequency characteristics of line and edge detectors evaluated psychophysically. Among the remaining cell types, concentric cells tend to be tuned to lower spatial frequencies and have broader bandwidths, whereas periodic cells prefer higher spatial frequencies and have narrower bandwidths. Thus the mean relative bandwidth tends to decrease significantly with spatial frequency (as required by a system of patch-by-patch Fourier analysis) only when cells with poor orientation selectivity and the non-linear silent periodic cells are included along with the simple cells. Simple cells, on their own, seem to form a quasi-linear contrast processing system which is more biased towards spatial accuracy than spatial frequency selectivity.Supported by the Wellcome Trust and the Alexander von Humboldt Foundation     

Persistent embryonic veins in the arteriovenous malformation of the telencephalon

The arterial components of the telencephalic arteriovenous malformations arise from the anterior cerebral and middle cerebral arteries. The complexity of the development process in this region obscures the fundamental segmental pattern. There are three regions where the primitive pial vessels cross at right angles. They are: a) over the convexity of the cerebral hemispheres, b) in the Sylvian territory, c) in the region of the basal ganglia. The malformations over the surface drain into the superior sagittal sinus. The Sylvian and deep telencephalic malformations drain primarily into the tentorial sinus, and this is often replaced by a medial drainage into the internal cerebral vein through the tributaries of the basal vein.     

Impact of education and training on neonatal resuscitation practices in 14 teaching hospitals in India

The impact of a neonatal resuscitation programme (NRP) on the incidence, management and outcome of birth asphyxia was evaluated in 14 teaching hospitals in India. Two faculty members from each institution attended a neonatal resuscitation certification course and afterwards trained staff in their respective hospitals. Each institution provided 3 months pre-intervention and 12 months post-intervention data. Introduction of the NRP significantly increased awareness and documentation of birth asphyxia, as judged by an increased incidence of asphyxia based on apnoea or gasping at 1 and 5 minutes (p < 0.001 and < 0.01, respectively). A significant shift towards more rational resuscitation practices was indicated by a decline in the use of chest compression and medication (p < 0.001 for each), and an increase in the use of bag and mask ventilation (p < 0.001). Although overall neonatal mortality did not decrease, asphyxia-related deaths declined significantly (p < 0.01).     

Child rearing and positive deviance in the development of preschoolers: a microanalysis

OBJECTIVE: To study the maternal child-rearing behaviors, parental attributes and socio-economic status of the family and to analyze their association with positive deviance in the developmental status of preschool children between 1-5 years of age. DESIGN: Cross-sectional. SETTING: Rural community. METHODS: A total of 260 children and their mothers were evaluated. Weight and height-for-age indices were used to assess growth. ICMR Developmental Screening Test was used to assess psychosocial development. Bhatia's Performance Test was used to assess maternal intelligence. Narayan Rao's Rating Scale was used to assess socio-economic status and a child-rearing interview schedule developed and pretested for the purpose of the study to assess maternal child-rearing practices and behaviors. RESULTS: Stepwise multiple regression with psychosocial development as dependent variable indicated significant associations between specific maternal behavioral categories and psychosocial development of 1-5 year old children. Children, whose mothers were responsive to their needs, were consistent in their interaction with them and were also emotionally stable during specific child rearing situations were those identified as "positive deviants" with regard to their development. Other factors, which were significantly associated with positive deviance in children, were paternal literacy and nuclear type of family. Significant differences were observed between genders. CONCLUSIONS: The data generated from the study could identify the important factors that were associated with "positive deviance" in the development of children. These factors can be useful components for parental counseling in clinical practice and as educational material in community programmes such as the ICDS and self-help groups at the village level.     

Long-term results after endoscopic sinus surgery involving frontal recess dissection

OBJECTIVE: To assess long-term follow-up on a cohort of patients who underwent endoscopic frontal sinus surgery with identification and preservation of the natural frontal outflow tract. STUDY DESIGN AND SETTINGS: Retrospective chart review, telephone interview, and endoscopic evaluation on a previously studied cohort of patients at a university affiliated medical center. RESULTS: Two hundred patients who underwent endoscopic frontal sinus surgery were previously studied and reported after short-term (mean = 12.2 mo) follow-up. One hundred fifty-two (76%) patients were available for long-term (mean 72.3 mo) follow-up and assessment of subjective symptoms. Fifty-seven of 152 (37.5%) patients also had nasal endoscopy for evaluation of objective findings. The percentage of patients responding to telephone interview reporting overall improvement after surgery was 92.4%. Endoscopic assessment revealed patency of the frontal sinus in 67.6% of the patients after initial surgery. Thirteen additional patients had patent sinuses after revision procedures, bringing overall patency rate to 71.1%. We found statistically significant correlation of asthma and smoking and poor subjective and objective outcome. CONCLUSION: Long-term assessment of subjective and objective findings in our previously reported cohort of patients who underwent frontal sinus surgery indicates that the frontal sinus, similar to any other sinus, can be successfully treated surgically by preserving the natural frontal sinus outflow tract.     

Type of Antifungals: Does it Matter in Empirical Treatment of Otomycosis?

To evaluate the efficacy of clotrimazole, miconazole and fluconazole in empirical treatment of otomycosis in our tertiary care hospital and to appraise possible better outcome in otomycosis. Two hundred and ninety five patients who presented with clinical otomycosis at our Melmaruvathur Adiparasakthi Institute of medical sciences were incorporated in this study. Two hundred and fourteen patients who satisfied our criteria were recognized and they were randomly alienated into three groups A, B, C. Group A patients were advised to instill clotrimazole ear drops by themselves. Miconazole cream instillation were done by our trained personal in group B patients. Group C patients were advised to use fluconazole ear drops. Patients were educated to keep ear dry and instructed to come for evaluation in first and second week after initial visit. A randomized double blinded prospective study. In the first week, clotrimazole had a good response than miconazole and fluconazole in our patients and in the second week, our patients showed a drastic response in patients instilling flucanozole ear drops compared to those using micanozole and clotrimazole. This better outcome doesn’t show statistical significance since p value is 0.882. Clotrimazole drops, miconazole cream and Fluconazole drops showed almost same therapeutic efficacy in Otomycosis