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F Masood

Publications and source records attributed to F Masood.

3 recordsLinked to original sources

An immunohistochemical study of neurotransmitter profiles in developing human visual cortex.

The temporal pattern of development and distribution of gamma aminobutyric acid, serotonin, substance P and neuropeptide Y immunoreactive profiles was studied in the human visual cortex from 16 to 26 weeks of gestation, using an immunohistochemical technique. The immunoreactive profiles showed an increase in number and a change in their morphology and distribution pattern over the time period studied. A large number of neurons, fibers and terminals were stained with GABA antibody at 17-18 weeks and were distributed throughout the five zones of the developing visual cortex. GABA neurons were non-pyramidal and bipolar in form at 17-18 weeks while at 18-19 and 20-21 weeks the cells of subplate and intermediate zones were multipolar. Substance P and serotonin immunopositive fibers were present mainly in the intermediate zone at 16 and 17-18 weeks, where they were oriented in a horizontal manner. At subsequent ages they invaded the other zones also. Substance P positive neurons could be visualized only at 26 weeks of gestation in the intermediate, subventricular and ventricular zones; no cell bodies, however, stained with serotonin antibody. Neuropeptide Y immunoreactive cells and fibers were first seen in the intermediate zone but later were found to be distributed in other zones too. The observations indicate that the intermediate zone of the visual cortex in which the transmitters and peptides appear earlier assumes importance in the normal development as also noted in other mammals.

Female↗

Early development of visual cortex in human fetuses.

Prenatal development of visual cortex (area 17) was studied in human fetuses of 8-9, 13-15 and 16-18 weeks of gestation, with a view to analyse the early critical events. Under light microscope, five zones of development were seen in all the age groups. The total thickness of cortex of area 17 as well as that of its cortical plate was measured with the help of camera lucida. It was observed that the total thickness of the cortex increased with increase in age. Diversity in the shape, size, staining intensity and arrangement of neurons was noted in the different zones. Most of the cells were found to have a thin rim of cytoplasm and a prominent nucleus with multiple nucleoli. The cells in subventricular zone and cortical plate were regularly arranged in vertical rows while in other zones, they were irregularly scattered. Several mitotic figures were seen in the ventricular zone at 8-9 weeks but later they were also noticed in subventricular and intermediate zones. In the later ages the mitotic figures were observed to be fewer in the ventricular zone. No mitosis was seen in cortical plate at any age period.

Cell Division↗