Modular Propagation of Epileptiform Activity: Evidence for an Inhibitory Veto in Neocortex

摘要: What regulates the spread of activity through cortical circuits? We present here data indicating a pivotal role for vetoing inhibition restraining modules pyramidal neurons. combined fast calcium imaging network with whole-cell recordings to examine epileptiform propagation in mouse neocortical slices. Epileptiform was induced by washing Mg2+ ions out slice. Pyramidal cells receive barrages inhibitory inputs advance wave. The are effectively nullified at low doses picrotoxin (2.5-5 microM). When present, however, these occlude an intense excitatory synaptic drive that would normally exceed action potential threshold approximately factor 10. Despite this level excitation, suppress firing, thereby limiting further neuronal recruitment ictal event. neurons recruited event once restraint fails and spatially clustered populations (150-250 microm diameter). within given module is virtually simultaneous, thus events progress intermittent (0.5-1 Hz) steps across network. propose interneurons supply define modular circuit territories.