Dead brain cells, or neurons, are eliminated through phagocytosis, a process performed by scavenger cells in the body called phagocytes, states Medical News Today. During neurogenesis (birth of neurons), thousands of brain cells are produced, yet only a small fraction of them survive as the rest die.
The process of phagocytosis prevents dead neurons from accumulating in the brain and allows new ones to grow, facilitating the regeneration process. A 2011 study found that the doublecortin, a type of progenitor cells, replenishes special cells and maintains intestinal, skin and blood tissues, besides performing repair functions in the body. Also called positive neuronal progenitors, the cells are capable of cleaning each other out, benefiting the regeneration process in the brain, according to Medical News Today.
The majority of the neurons in the brain are present at birth, and although many neuroscientists do not agree on the extent of neurogenesis, others believe that the creation of new brain cells continues throughout adulthood, notes the National Institute of Neurological Disorders and Stroke. As new neural cells are formed, are differentiated and migrate to their designated loci, some of them die. If the brain cells were left to accumulate in the brain, they could impair brain function. The scavenger cells consume the dead cells, cleansing the brain.