Layer 3 patchy recurrent excitatory connections may determine the spatial organization of sustained activity in the primate prefrontal cortex

Anatomical studies of primate prefrontal cortex show strong and spatially m odulated lateral excitatory connections among pyramidal neurons in the supr a-granular layers. We study the role of patchy lateral excitatory connectio ns in generating spatially localized pulses of sustained activity. When the patchy connections drive the firing no spatially localized sustained activ ity is possible. When the local connectivity is strong enough to produce su stained activity, a localized standing pulses are possible. Additional punc tate stimuli boost, or extinguish the standing pulse-system depending on th eir spacing. When the patchy lateral connections form distinct sub-systems, spatially restricted systems of multiple pulses of sustained activity are observed over a wide range of connection strength parameters. (C) 2000 Publ ished by Elsevier Science B.V. All rights reserved.