Neurogenesis continues through the remainder of the prenatal period but is largely complete by the end of the __ month after conception.
A fourth
B fifth
C sixth
D seventh
The correct answer and explanation is:
The correct answer is A. Fourth.
Neurogenesis refers to the process of generating new neurons in the brain, a key event during early brain development. During the prenatal period, neurogenesis begins shortly after conception, with neurons being produced in large numbers. By the end of the fourth month of pregnancy, the majority of neurogenesis is largely complete. This means that most of the neurons that will populate the brain have already been created.
The development of the brain is a highly organized and regulated process. Early on, neural stem cells divide to produce progenitor cells, which then differentiate into the various types of neurons and glial cells (support cells). This process peaks around the third to fourth month of pregnancy. After this point, the focus of brain development shifts more towards the maturation, migration, and connection of neurons, as well as the development of brain structures and functions.
However, neurogenesis doesn’t end completely after the fourth month. There are certain regions in the adult brain, like the hippocampus (involved in memory and learning), where neurogenesis continues throughout life. This phenomenon, known as adult neurogenesis, is far less pronounced than during prenatal development. But the large-scale production of neurons during prenatal development is crucial for forming the brain’s basic structure.
By the end of the fourth month, most of the neurons that will be needed for the individual’s lifetime are already produced and start to undergo differentiation, forming more complex networks that are essential for brain function. This process is essential for cognitive, motor, and sensory abilities in later stages of development.