Functional MRI Based Brain Mapping in Occipital Gyrus using Face Stimuli

Functional magnetic resonance imaging (fMRI) is one of the most powerful neuroimaging modalities due to its high spatio-temporal resolution characteristics. This known modality is applied on mapping the temporal, occipital, frontal cortices of the brain for localizing the neural activities generated due to any visual, physical or mental task or brain diseases or brain disorders. The occipital cortex is composed of middle, left, right, interior and exterior occipital gyrus and is responsible for visional function of human brain. The occipital gyrus reflects the neural image generated in the brain due to any visual activity. In this research paper, four different visual stimuli images of faces, scrambled, scenes and objects along with gap of blank space, forming a long sequence of stimuli observed by two female subjects, are experimented to examine and localize the most contrasting neural image generated in occipital gyrus of the brain. The visual fMRI brain data received from the two subjects is processed through fMRI-SPM12 toolbox based on Matlab software. In order to demonstrate the results statistically, two regressions such as T-contrast and F-contrast vectors are applied on fMRI images to highlight, and to localize the most active neural stimuli activities generated in the occipital gyrus of brain. In the results, it is demonstrated that maximum neural response can be mapped only for face stimulus in the bilateral occipital gyrus of the brain by applying T-contrast vectors regressions as when compared to other stimuli conditions and F-contrast vectors regressions. Further, it is also investigated that, the response of the face stimulus in F-contrast regressions achieved is somehow dispersed and unclear due to the large variances and interlinked communication of other stimuli or induced neural noises generated in entire volume of the brain.  Further from the given images, it is also investigated that the most reflecting and contrast area for any visual stimuli (such as face stimulus in this case) is either the middle or bilateral part of occipital gyrus of the human brain as identified through application of  T-contrast vectors regressions.

Development of an Indigenous Real Time Polymerase Chain Reaction for the Diagnosis of Malaria

INTRODUCTION Establishing highly sensitive, affordable diagnostic test covering all species of malaria is needed in countries like Pakistan that has significant prevalence of this disease. Conventional tests, like microscopy are widely used but it has certain performance related limitations. Rapid diagnostic tests (RDTs) for plasmodium have not achieved greater sensitivity than microscopy. Polymerase chain reaction (PCR) based methods have shown lot of promise and these are replacing microscopy as gold standard. OBJECTIVES To establish a real time PCR for malaria diagnosis and to compare its accuracy with microscopy and an antigen based RDT. STUDY DESIGN AND SETTING This cross sectional analytical study was conducted at Military Hospital and Armed forces Institute of Pathology Rawalpindi, Pakistan from January 2011 to December 2011. SUBJECTS The study included 300 clinically suspected patients of malaria. 3 METHODS Venous blood sample from each patient was tested for malarial parasite by microscopy and antigen detection assay (OptiMal). Parasite index was calculated. Plasmodium genus specific in house real time PCR, on all specimens was performed targeting small subunit rRNA gene. Diagnostic accuracy of three tests were compared and cost analysis done. RESULTS Out of 300 patients malaria parasite was detected in 110, 106 and 123 patients by microscopy, OptiMAL and PCR respectively. Real time PCR was 100% sensitive while microscopy and OptiMal had sensitivity of 89.4% and 86.2% respectively. All methods were 100% specific. The cost per test was 0.2, 2.75 and 3.30 US$ by microscopy, OptiMal and PCR respectively, excluding the once capital cost on PCR equipment. Conclusion: Real time PCR for diagnosis of malaria was successfully established. The technique is highly sensitive and affordable. It is recommended to be incorporated in the diagnostic algorithm for malaria in Pakistan. Key Words: Malaria, Microscopy, Rapid Diagnostic Tests (RDTs), Polymerase Chain Reaction (PCR).