How do nerve cells form different types of tissues?
a. a group of these tissues perform similar functions and become nerve organs after messages from the heart tell nerve cells to develop and perform special functions.
b. a group of these cells perform similar functions and become nerve systems after information in the rna of the nucleus tells nerve tissues how to develop and to perform special functions.

b. A group of these cells perform similar functions and become nerve systems after information in the RNA of the nucleus tells nerve tissues how to develop and to perform special functions.

The neuron, a cell that composes the nervous system. For example a brain, an organ composed of thousands of neural fibers and glial cells that performs many important organismic functions. 
Neurons are specialised cells that have dendrites, axons and terminal buttons that sends and receives stimuli from the environment and transduces it into a meaningful information and understand the complexities which the brain now functions.