Model of cellular and network mechanisms for odor-evoked temporal patterning in the locust antennal lobe

Locust antennal lobe (AL) projection neurons (PNs) respond to olfactory sti muli with sequences of depolarizing and hyperpolarizing epochs, each lastin g hundreds of milliseconds. A computer simulation of an AL network was used to test the hypothesis that slow inhibitory connections between local neur ons (LNs) and PNs are responsible for temporal patterning. Activation of sl ow inhibitory receptors on PNs by the same GABAergic synapses that underlie fast oscillatory synchronization of PNs was sufficient to shape slow respo nse modulations. This slow stimulus- and neuron-specific patterning of AL a ctivity was resistant to blockade of fast inhibition. Fast and slow inhibit ory mechanisms at synapses between LNs and PNs can thus form dynamical PN a ssemblies whose elements synchronize transiently and oscillate collectively , as observed not only in the locust AL, but also in the vertebrate olfacto ry bulb.