AP Psychology Practice Test

The correct answer emphasizes the critical function of neurotransmitters as chemical messengers that facilitate communication between neurons. When a neuron fires, it releases neurotransmitters into the synaptic gap, which is the space between neurons. These neurotransmitters bind to the receptors on the surface of the adjacent neuron, thereby transmitting signals that can either initiate or inhibit the firing of that neuron. This process is essential for the functioning of the nervous system, influencing everything from muscle movement to mood regulation. The other options pinpoint roles that are not associated with neurotransmitters. For instance, the formation of the myelin sheath involves glial cells that provide insulation for neurons, enhancing signal transmission speed, while the creation of the synaptic gap is a structural feature of neuronal connections rather than a function of neurotransmitters. Additionally, neurotransmitters do not physically move neurons; rather, they play a role in signaling within the network of neurons already in place. This highlights the distinction between the structural and functional components involved in neural communication.