A Caltech Library Service

Oscillatory Sequences of Firing in the Locust Olfactory System: Mechanisms and Functional Significance


Wehr, Michael Stephen (1999) Oscillatory Sequences of Firing in the Locust Olfactory System: Mechanisms and Functional Significance. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/QZE9-SZ72.


What neural codes does the brain use to represent and process sensory information? Stimulus-evoked oscillatory synchronization of neuronal activity has been observed in many systems, yet the possible functions of such rhythmic synchronization in neural coding remain largely speculative. In the locust, odors appear to be represented by dynamic ensembles of transiently synchronized neurons. The experiments described here explored the design and function of the locust olfactory system, focusing on projection neurons in the antennal lobe. The first goal was to characterize, by means of intracellular and multiple extracellular recordings, the oscillatory synchronization and slow temporal patterns in PN odor responses in vivo. After the system had been characterized, specific coding hypotheses were tested. The results demonstrated that the cycle-by-cycle firing patterns across ensembles of PNs encode odor identity information, but that other response features (such as phase or frequency) do not. Finally the mechanisms for the generation of these dynamics were addressed. Odors do not evoke oscillatory synchronization in the population activity of olfactory receptor afferents, and non-specific, temporally unpatterned electrical stimulation of receptor axons can evoke both oscillatory synchronization and slow temporal patterns in PNs, similar to those evoked by natural stimulation with odors. Oscillatory synchronization of olfactory neurons therefore originates in the antennal lobe, and slow temporal patterns in projection neurons can arise in the absence of temporal patterning of the afferent input.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:neuroscience ; Computation and Neural Systems
Degree Grantor:California Institute of Technology
Major Option:Computation and Neural Systems
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Laurent, Gilles J.
Thesis Committee:
  • Laurent, Gilles J. (chair)
  • Koch, Christof
  • Schuman, Erin Margaret
  • Konishi, Masakazu
  • Andersen, Richard A.
Defense Date:1 September 1998
Non-Caltech Author Email:wehr (AT)
Record Number:CaltechETD:etd-05212002-120039
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:1902
Deposited By: Imported from ETD-db
Deposited On:28 May 2002
Last Modified:31 Aug 2022 00:06

Thesis Files

PDF (mike-thesis.pdf) - Final Version
See Usage Policy.


Repository Staff Only: item control page