Encoding a temporally structured stimulus with a temporally structured neural representation

Nat Neurosci. 2005 Nov;8(11):1568-76. doi: 10.1038/nn1559. Epub 2005 Oct 16.

Abstract

Sensory neural systems use spatiotemporal coding mechanisms to represent stimuli. These time-varying response patterns sometimes outlast the stimulus. Can the temporal structure of a stimulus interfere with, or even disrupt, the spatiotemporal structure of the neural representation? We investigated this potential confound in the locust olfactory system. When odors were presented in trains of nearly overlapping pulses, responses of first-order interneurons (projection neurons) changed reliably, and often markedly, with pulse position as responses to one pulse interfered with subsequent responses. However, using the responses of an ensemble of projection neurons, we could accurately classify the odorants as well as characterize the temporal properties of the stimulus. Further, we found that second-order follower neurons showed firing patterns consistent with the information in the projection-neuron ensemble. Thus, ensemble-based spatiotemporal coding could disambiguate complex and potentially confounding temporally structured sensory stimuli and thereby provide an invariant response to a stimulus presented in various ways.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Intramural

MeSH terms

  • Action Potentials / drug effects
  • Action Potentials / physiology*
  • Animals
  • Dose-Response Relationship, Drug
  • Female
  • Grasshoppers
  • Male
  • Models, Neurological
  • Neurons / classification
  • Neurons / physiology*
  • Odorants*
  • Olfactory Pathways / cytology*
  • Olfactory Pathways / physiology
  • Stimulation, Chemical
  • Time Factors