What characteristic of brain cells is primarily involved in signal transmission?

The primary characteristic of brain cells that is involved in signal transmission is axon terminals. Axon terminals are the endpoints of a neuron where the axon extends and synapses with another neuron or an effector, such as a muscle or gland. When a neural impulse reaches the axon terminals, it triggers the release of neurotransmitters from vesicles into the synaptic cleft, facilitating communication between neurons. This process is essential for the transmission of signals across the nervous system, allowing for quick and efficient communication.

Other components of neurons, such as dendrites, soma, and nucleus, play important roles as well. Dendrites receive incoming signals from other neurons, the soma contains the cell's nucleus and integrates the information, and the nucleus houses the genetic material crucial for the functioning of the neuron. However, the axon terminals are specifically critical for the final step of signal transmission in neural communication.