As stem cells begin to become neurons, where do they seems to get their information from in order to know what kind of neuron to become? DNA strictly dictates all instructions Neurons do not come from stem cells. The neighboring neurons provide information and the new neuron takes on properties of the surrounding neurons.
The correct answer and explanation is:
Correct Answer: The neighboring neurons provide information and the new neuron takes on properties of the surrounding neurons.
Explanation (300 words):
When stem cells differentiate into neurons, they don’t act solely on a rigid, predetermined DNA-based script. While their DNA provides the foundational blueprint, the decision of what kind of neuron they become is heavily influenced by external signals—particularly those from their environment, including neighboring neurons. This process is known as inductive signaling and is a key part of developmental biology and neurogenesis.
During brain development, neural stem cells (NSCs) respond to various chemical signals, such as growth factors (e.g., brain-derived neurotrophic factor, or BDNF) and signaling molecules like Sonic Hedgehog (Shh), Wnt, and Notch. These molecules help instruct cells about what fate to take on. Importantly, neighboring cells—especially other neurons and glial cells—release some of these signals. Through cell-to-cell interactions and diffusible chemical cues, developing neurons receive positional and functional information that guides them to become a specific type of neuron (e.g., motor neuron, sensory neuron, interneuron).
For instance, in the developing spinal cord, gradients of signaling molecules help progenitor cells determine whether they become motor neurons or interneurons. Similarly, in the cerebral cortex, local signals from other neurons help determine layer-specific identities.
This mechanism ensures that neurons integrate correctly into existing neural circuits, adopting the right properties and connections needed for coordinated function. It also enables a high degree of plasticity and adaptability, allowing the nervous system to fine-tune development in response to both genetic instructions and the local cellular environment.
In summary, while DNA gives stem cells their potential, environmental context—especially signals from nearby neurons—plays a decisive role in determining what kind of neuron a stem cell ultimately becomes.