"Excitatory" refers to a type of signal in the nervous system that promotes the activation of neurons. When an excitatory neurotransmitter, such as glutamate, binds to its receptor on a neuron, it increases the likelihood that the neuron will fire an action potential. This process is essential for communication between nerve cells and plays a crucial role in various brain functions, including learning and memory. In contrast to inhibitory signals, which decrease neuronal activity, excitatory signals enhance the transmission of information. This balance between excitatory and inhibitory signals is vital for maintaining proper brain function and overall neural health, influencing everything from reflexes to complex behaviors.