The C. Elegens "Brain"

 C. elegens does not have a brain in the usual sense of the word but has a ring of neurons composed of axonal and dendritiuc processes, clusters of cephalic neuronal cell bodies (‘ganglia’), a ventral nerve cord  containing processes and motor neuron cell bodies, and a dorsal nerve cord and circumferential commissures  consisting exclusively of processes. The neuropil (comprising nerve ring and cords) is shown above in red, neuronal cell bodies in yellow, muscles in blue, gut in green. The dorsal portion of the nerve ring is shown schematically in the illustration below. 

It is within this concentrated are of neurons, not unlike the human brain, C. elegens do their thinking through electrical and chemical signaling between each other. It is where the sensory signals from all 302 neural cells are processed. The human brain, by contrast, processes the sensory signals from 86 billion neural cells but both C. elegens and humans both provide for the biological imperatives of living and reproducing  essential for the continued life of of their species. The difference is in signal data processing with C. elegans being analogous to searching for a word in a dictionary and humans to the computer used by Google to do 99,000 searches every second. It is only the amount of "brain power",, legs and arms that separates us.

Interestingly, humans have very similar "|brain" called the enteric nervous system (ENS). And  is two thin layers of more than 100 million nerve cells lining your gastrointestinal tract from esophagus to rectum.a nd controls our gastrointestinal tract independently from the brain in our head. Buit it does send signal to the brain in our head.That "butterflies in your stomach” feeling results from these signals. It controls digestion, from swallowing to the release of enzymes that break down food to the control of blood flow that helps with nutrient absorption to elimination of feces.The ENS may trigger emotional shifts experienced by people coping with irritable bowel syndrom syndrome   and functional bowel problems such as castipatio0n, diarrhea, bloating, pain and stomach upset. But, like the neutral system of C.elegens, it does not creat consciousness or conscious thought. It is strictly functional.