Glomerular layer model.

(A) 16 glomerulus connected through SAs. The thick red line represents full connectivity between glomerulus. b) Architecture of the glomerular unit. The cells depicted are: mitral cell (MC), external tufted cell (ET), periglomerular cell (PG), and short axon (SA). Black balls represent inhibitory synapses and red balls indicate excitatory synapses. The ORN input synapses into MC, ET and PG cells. MC and PG cells form a negative feedback loop, where PG cells inhibit MC cells and in turn MC excite PG cells. ET cells contribute to the inhibition of MC through an excitatory connection to PG cells. Finally, connections between glomerulus are achieved via SA cells, which receive excitatory inputs from ET cells and transmit its outputs to PG and ET in an excitatory fashion.