Recurrent circuitry dynamically shapes the activation of piriform cortex.

Journal Article (Journal Article)

In the piriform cortex, individual odorants activate a unique ensemble of neurons that are distributed without discernable spatial order. Piriform neurons receive convergent excitatory inputs from random collections of olfactory bulb glomeruli. Pyramidal cells also make extensive recurrent connections with other excitatory and inhibitory neurons. We introduced channelrhodopsin into the piriform cortex to characterize these intrinsic circuits and to examine their contribution to activity driven by afferent bulbar inputs. We demonstrated that individual pyramidal cells are sparsely interconnected by thousands of excitatory synaptic connections that extend, largely undiminished, across the piriform cortex, forming a large excitatory network that can dominate the bulbar input. Pyramidal cells also activate inhibitory interneurons that mediate strong, local feedback inhibition that scales with excitation. This recurrent network can enhance or suppress bulbar input, depending on whether the input arrives before or after the cortex is activated. This circuitry may shape the ensembles of piriform cells that encode odorant identity.

Full Text

Duke Authors

Cited Authors

  • Franks, KM; Russo, MJ; Sosulski, DL; Mulligan, AA; Siegelbaum, SA; Axel, R

Published Date

  • October 6, 2011

Published In

Volume / Issue

  • 72 / 1

Start / End Page

  • 49 - 56

PubMed ID

  • 21982368

Pubmed Central ID

  • PMC3219421

Electronic International Standard Serial Number (EISSN)

  • 1097-4199

Digital Object Identifier (DOI)

  • 10.1016/j.neuron.2011.08.020


  • eng

Conference Location

  • United States