A Caltech Library Service

Neural Encoding of Mixtures and Stimulus Generation in the Insect Brain


Shen, Kai (2010) Neural Encoding of Mixtures and Stimulus Generation in the Insect Brain. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/MDZC-0J48.


Sensory object recognition is the most fundamental of operations performed by the brain. A key computational difficulty of object recognition is that it requires both selectivity to particular objects (e.g., exact odor mixture identification) and generalization across objects (identifying particular features or components common to different odors). Although previous results (1) suggest that odor identity and intensity are represented in the activity of both PNs and KCs, it is not clear how these representations generalize across complex odor mixtures. In particular, it is not clear what types of information are available in KC population (or if its even possible to decode across KC populations?) and how is this information represented? Using the locust olfactory system as a model system, we found that Kenyon cells (KCs), the principal neurons of the mushroom body, an area required for associative learning can identify the presence of components in mixtures and thus enable odor segmentation. As a population, small groups of KCs can both identify and categorize odors with high accuracy. We identified and tested simple circuit requirements for this computation, and propose that odor representations in mushroom bodies are optimized for odor memorization, identification and generalization. These rules may be relevant for pattern classifying circuits in general.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:Olfaction; odor segmentation; odor generalization; neural coding; classification; Kenyon cells; sparse code;
Degree Grantor:California Institute of Technology
Division:Engineering and Applied Science
Major Option:Computation and Neural Systems
Awards:Lucy Guernsey Service Award, 2006.
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Laurent, Gilles J.
Thesis Committee:
  • Winfree, Erik (chair)
  • Koch, Christof
  • Siapas, Athanassios G.
  • Dickinson, Michael H.
  • Laurent, Gilles J.
Defense Date:17 March 2010
Non-Caltech Author Email:kai (AT)
Record Number:CaltechTHESIS:09122010-130333994
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:6028
Deposited By: Kai Shen
Deposited On:01 Nov 2010 21:06
Last Modified:30 Aug 2022 22:52

Thesis Files

PDF (Full thesis) - Final Version
See Usage Policy.

[img] PDF (Thesis Main) - Final Version
See Usage Policy.

PDF (Abstract and contents) - Final Version
See Usage Policy.


Repository Staff Only: item control page