||Many useful facts related to neurons at the cited website. For synaptic cleft width of ~20nm see Barberis et al., 2011 PMID 21734864 p.2 of 16 left column 2nd paragraph: "Typically, at the central synapses, cleft width is
~20nm, thus precluding placement of a measuring device within the synapse
to directly monitor the agonist time course." See Ahmari 2002 PMID 11988164 p.333 right column 4th paragraph [organism is rat]:"Mature CNS synapses share an established set of ultrastructural characteristics. The canonical excitatory synapse comprises presynaptic and postsynaptic active zones separated by a uniform 20 nm cleft (Figure 1A)."