deletions | additions       diff --git a/what_is_known_about_pumping__.tex b/what_is_known_about_pumping__.tex  index 4a79b5f..8dac988 100644  --- a/what_is_known_about_pumping__.tex  +++ b/what_is_known_about_pumping__.tex 
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  Bacterial lawns on standard cultivation plate are typically highly concentrated and large. Under these conditions, reported pumping rates is typically 3-4 Hz and the duration of a single pump (constrained by the physiology of the pharynx) is approximately 170 ms. The pharynx is separated from the rest of the body by the basal lamina, an extracellular formation of connective tissue. It contains 20 muscle cells and 20 neurons. Of these, only the MC cholinergic motoneurons were found to be individually required for rapid pumping in the presence of food \cite{avery1989pharyngeal,raizen1995}. The cholinergic neurons M2, M4, MC, and I1 form a degenerate network, excitatory for pumping and robust, where I1 can activate both MC and M2 \cite{trojanowski2014neural}. In addition, the glutamatergic M3 neurons regulate the termination of a pump and M4 regulates isthmus peristalsis \cite{avery1989pharyngeal,raizen1995}. Under standard conditions, M3, M4, and MC are sufficient for supporting nearly normal feeding and growth \cite{raizen1995,AveryWormbook2012}. \cite{raizen1995,avery2012}.  The functions of additional pharyngeal neurons are poorly understood. In part, this may be due to the challenges of characterizing the phenomenology of pharyngeal pumping more systematically.