P Syamasundar Rao

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Coarctation of the Aorta (CoA) is a congenital cardiac anomaly consisting of a constricted aortic segment with a prevalence of 5 to 8% of all Congenital Heart Defects (CHD). The classic CoA is located in the thoracic aorta distal to the origin of the left subclavian artery, at about the level of the ductal structure. Significant hypertension and/or(More)
The purpose of this review/editorial is to discuss how and when to treat the most common acyanotic congenital heart defects (CHD); the discussion of cyanotic heart defects will be presented in a subsequent editorial. By and large, the indications and timing of intervention are decided by the severity of the lesion. Balloon pulmonary valvuloplasty is the(More)
Six rats bar-pressed for intracranial self-stimulation in a Skinner box on fixed interval and differential reinforcement of low rate schedules with an interval parameter of 1.3 s. After amphetamine timing efficiency was reduced immediately on both the schedules; it recovered after 60 min on the DRL schedule but not within 120 min on the FI schedule.(More)
Rats were studied for their performance on DRL 10 s and 5 s with 50% probability of reinforcement, before and after medial frontal cortical lesions. A sequential analysis of interresponse times (IRTs) was carried out. It suggested 1. that the medial frontal cortex mediates subjective risk of response choice in rats and 2. that the tolerated risk levels in(More)
Rats were studied for their performance on DRL 10-s schedule with a 50% probability of reinforcement of a correct response with a food pellet. It was found that the performance of a group of 8 rats with medial frontal decortication by aspiration was deficient compared to a group of 7 sham-operated control rats. The deficit manifested in the form of an(More)
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