Ganglion

The plural of ganglion is ganglia.

In the past, there were certain traditions that could not be avoided. Thus, to eat kidney, children were obliged, the very first time, to nibble it on their knees on their fathers' shins. Otherwise, it was said that there was a risk that a ganglion would appear on the child's neck or face.

They've created a prosthetic device with an encoder that mimics the neural language or pulses that are normally sent from the retina's ganglion cells to the brain where it is deciphered and perceived as imagery.

I have a ganglion in my right groin.

[T]he wonderfully diversified instincts, mental powers, and affections of ants are generally known, yet their cerebral ganglia are not so large as the quarter of a small pin's head.

The yawning gap in neuroscientists’ understanding of their topic is in the intermediate scale of the brain’s anatomy. Science has a passable knowledge of how individual nerve cells, known as neurons, work. It also knows which visible lobes and ganglia of the brain do what. But how the neurons are organised in these lobes and ganglia remains obscure.