ADD / ADHD, Memory, Science

Prunning

Following up on the research described in ADHD and Gifted Children, Developing Intelligence has an excellent article on the neurology of the child brain.
Although the metabolic efficiency is improved, this comes at a price, as discovered by the authors in simulating pruning in the midst of learning (just as actually occurs in childhood). Adult networks that undergo synaptic pruning actually lose the ability to retrieve the earliest memories. In humans, this phenomenon is known as ‘childhood amnesia,’ in which memories before the age of 5 are hazy, and those before 3 are almost completely inaccessible. This amnesia emerges from the networks because the earliest memories are stored in a highly distributed fashion, relying on many different neurons, while later memories are stored in a more sparse format. Therefore, early memories are more degraded by the pruning strategy because of sheer probability: more neurons participate in their representation, so they are more easily affected by changes to the network.
Overgrowth, Pruning and Infantile Amnesia