Human Adult Neurogenesis: Evidence and Remaining Questions

Genetic variations accumulating within populations over generations give rise to biological evolution. Evolutionary changes can result in the formation of novel varieties and entire new species. These changes are responsible for the diverse forms of life inhabiting the planet. The evidence for evolution suggests that all living organisms descended from common ancestors.

In the CNS, neurogenesis, the birth of new neurons from stem cells, is limited to the hippocampus in adults. In other regions of the brain and spinal cord, neurogenesis is almost non-existent due to inhibitory influences from neuroglia, especially oligodendrocytes, and the absence of growth-stimulating cues. The myelin produced by oligodendrocytes in the CNS inhibits neuronal regeneration. Furthermore, astrocytes proliferate rapidly after neuronal damage, forming scar tissue that physically...

Stem cells are undifferentiated cells that divide and produce more stem cells or progenitor cells that differentiate into mature, specialized cell types. All the cells in the body are generated from stem cells in the early embryo, but small populations of stem cells are also present in many adult tissues including the bone marrow, brain, skin, and gut. These adult stem cells typically produce the various cell types found in that tissue—to replace cells that are damaged or to continuously...

Cardiopulmonary resuscitation, or CPR, is a life-saving emergency procedure performed when a person's heart has stopped beating or they are no longer breathing. The foundation of CPR is Basic Life Support (BLS), which focuses on the early recognition of cardiac arrest, the immediate start of high-quality chest compressions, and the timely use of an automated external defibrillator (AED).Assessing Responsiveness and Checking the Carotid PulseWhen approaching an unresponsive person, first ensure...

Other adult family members and siblings play a crucial role in shaping children’s social and emotional development. While parents or primary caregivers are often the central figures in early attachment and socialization, other adults in a child’s life, such as grandparents, aunts, and uncles, can significantly influence developmental outcomes. These influences depend on each adult’s personality and may help compensate when a primary caregiver is emotionally distant or...

Human civilization relies on biodiversity in many ways. Sudden changes in species biodiversity result in environmental changes that can modify weather patterns and therefore human civilizations.