Synapse formation & AD The connections in the brain, called synapses, are continuously re-formed throughout life. This means that existing synapses are replaced every 3-6 months with new ones. In a healthy brain the amount of new synapses that are formed matches the amount that are lost. In early Alzheimer’s disease however, the loss of synapses becomes accelerated. It is not yet understood why this is the case, however research suggests that synaptic loss occurs very early in the disease progression. The loss of synapses is one of the key features of early Alzheimer’s disease.