Mechanism for Temporal Encoding in Fear Conditioning

Delay Lines in Perirhinal Cortex and Lateral Amygdala
  • Billie Faulkner
  • Kinh H. Tieu
  • Thomas H. Brown


Our neurobiological studies of the lateral amygdala (LA) and perirhinal cortex (PR) suggest a novel and testable hypothesis regarding encoding the time interval between the conditioned stimulus (CS) and unconditioned stimulus (US) in fear conditioning. In such conditioning, the interval between the onset of the CS and the onset of the US can be several seconds or longer. Here we outline our working hypothesis in qualitative terms, showing how the functional anatomy and neurophysiology furnish a platform for encoding the CS-US interval by mapping time onto space and then relying upon a conventional Hebbian learning rule in which the modifications require temporal contiguity of pre- and postsynaptic activity.


Conditioned Stimulus Unconditioned Stimulus Fear Conditioning Delay Line Perirhinal Cortex 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    Brandon, S. E., Bombace, J. C., Falls. W. A., & Wagner, A. R. 1991. Modulation of unconditioned defensive reflexes by a putative emotive Pavlovian conditioned stimulus.J. Evp. Psych.: Animal Behavior Processes, 17, 312–322.CrossRefGoogle Scholar
  2. 2.
    Brown, T. H., Ganong, A. H., Kairiss, E. W., & Keenan, C. L. 1990. Hebbian synapses: Biophysical mechanisms and algorithms.Ann. Rev. Neurosci., 13, 475–512.PubMedCrossRefGoogle Scholar
  3. 3.
    Burwell, R. D., Witter, M. P. & Amaral, D. G. 1995. The perirhinal and postrhinal cortices of the rat: A review of the neuroanatomical literature and comparison with findings from the monkey brain.Hippocampus, 5, 390–408.PubMedCrossRefGoogle Scholar
  4. 4.
    Buonomano, D. V. & Mauk, M. D. 1994. Neural network model of the cerebellum: Temporal discrimination and the timing of motor responses.Neural Computation, 6, 38–55.CrossRefGoogle Scholar
  5. 5.
    Buonomano, D. V. & Merzenich, M. M. 1995. Temporal Information transformed into a spatial code by a neural network with realistic properties.Science, 267, 1028–1030.PubMedCrossRefGoogle Scholar
  6. 6.
    Carr, C. E. Konishi, M. 1988. Axonal delay lines for time measurement in the owl’s brainstem.Proc. Natl. Acad. Sci., 85. 8311–8316.Google Scholar
  7. 7.
    Chapman. P. F., Kairiss, E. W., Keenan C. L. & Brown, T. H. 1990. Long-term synaptic potentiation in the amygdala.Synapse, 6, 271–278.PubMedCrossRefGoogle Scholar
  8. 8.
    Corodimas, K. P. & LeDoux, J. E. 1996. Disruptive effects of post-training perirhinal cortex lesions on conditioned fear: Contributions of contextual cues.Behay. Neurosci., 109 (4), 613–619.Google Scholar
  9. 9.
    Davis, M., Schlesenger, L. S. Sorenson, C. A., 1989. Temporal specificity of fear conditioning: effects of different conditioned stimulus-unconditioned stimulus intervals on the fear-potentiated startle effect.J. Exp. Psych.: Animal Behavior Processes, 15, 295–310.Google Scholar
  10. 10.
    Faulkner. B Brown, T. H. 1996. Spatial organization and diversity of neurons in the rat perirhinal-lateral amygdala region.Soc. Neurosci. Abstr, 22, 17–42.Google Scholar
  11. 11.
    Kelso, S. R., Ganong, A. Brown, T. H. 1986. Hebbian synapses in hippocampus.Proc. Natl Acad. Sci., 83, 5326–5330.Google Scholar
  12. 12.
    Moore, J. W. Desmond, J. E. 1988. Adaptive Timing in Neural Networks: The Conditioned Response.Biol C’vbern. 58, 405–515.Google Scholar
  13. 13.
    Lam, Y. W., Wong, A., Canli, T. & Brown, T. H. 1996. Conditioned enhancement of the early component of the rat eyeblink reflex.Neurobiol. Learn. Mein.,in press.Google Scholar
  14. 14.
    LeDoux, J. E. 1993. Emotional memory systems in the brain.Behay. Brain Res. 58, 69–79.CrossRefGoogle Scholar
  15. 15.
    Quirk, G. J., Repa, J. C., LeDoux,,1. F. 1995. Fear conditioning enhances short latency auditory responses of neurons in the lateral nucleus of the amygdala: Parallel recordings in freely behaving rats.Neuron,15(5), 1029–1039.Google Scholar
  16. 16.
    Thompson, R. F. & Krupa, D. J. 1994. Organization of memory traces in the mammalian brain.Ann. Rev. Neurosci., 17, 519–549.PubMedCrossRefGoogle Scholar
  17. 17.
    Tieu, K. H., Faulkner, B. Brown, T. H. 1996. Perirhinal-Amygdala neural network model of temporal encoding in fear conditioning.Soc. Neurosci. Abstr, 22, 17–42.Google Scholar

Copyright information

© Springer Science+Business Media New York 1997

Authors and Affiliations

  • Billie Faulkner
    • 1
  • Kinh H. Tieu
    • 2
  • Thomas H. Brown
    • 2
  1. 1.Interdepartmental Neuroscience ProgramUSA
  2. 2.Departments of Psychology and Cellular and Molecular PhysiologyYale UniversityNew HavenUSA

Personalised recommendations