Synapse efficiency diverges due to synaptic pruning following over-growth

In the development of the brain, it is known that synapses are pruned following over-growth. This pruning following over-growth seems to be a universal phenomenon that occurs in almost all areas -- visual cortex, motor area, association area, and so on. It has been shown numerically that the synapse efficiency is increased by systematic deletion. We discuss the synapse efficiency to evaluate the effect of pruning following over-growth, and analytically show that the synapse efficiency diverges as O(log c) at the limit where connecting rate c is extremely small. Under a fixed synapse number criterion, the optimal connecting rate, which maximize memory performance, exists.Comment: 15 pages, 16 figure

Neurocognitive Aspects of Pediatric Sickle Cell Disease

Studies pertaining to the neurocognitive functioning and learning of children in whom sickle cell disease is diagnosed are reviewed, and findings suggest diffuse neurocognitive deficits, with much variability across subjects. A hypothesis is presented about the cumulative nature of such deficits in children who have not sustained cerebral vascular accidents. Important methodological shortcomings in the literature are identified and recommendations are made for future neurocognitive research with children in whom sickle cell disease has been diagnosed. Studies pertaining to the psychosocial development of these children are also reviewed, and it is concluded that behavioral problems, low self-esteem, and disturbances of body image are frequently characteristic of these children. Recommendations are made including early special education and psychosocial intervention programs for children with sickle cell disease