Journal of Comparative Physiology A

, Volume 193, Issue 1, pp 13–20 | Cite as

FM signals produce robust paradoxical latency shifts in the bat’s inferior colliculus

  • Xinming Wang
  • Alexander V. Galazyuk
  • Albert S. Feng
Original Paper


Previous studies in echolocating bats, Myotis lucifugus, showed that paradoxical latency shift (PLS) is essential for neural computation of target range and that a number of neurons in the inferior colliculus (IC) exhibit unit-specific PLS (characterized by longer first-spike latency at higher sound levels) in response to tone pulses at the unit’s best frequency. The present study investigated whether or not frequency-modulated (FM) pulses that mimic the bat’s echolocation sonar signals were equally effective in eliciting PLS. For two-thirds of PLS neurons in the IC, both FM and tone pulses could elicit PLS, but only FM pulses consistently produced unit-specific PLS. For the remainder of PLS neurons, only FM pulses effectively elicited PLS; these cells showed either no PLS or no response, to tone pulses. PLS neurons generally showed more pronounced PLS in response to narrow-band FM (each sweeping 20 kHz in 2 ms) pulse that contained the unit’s best frequency. In addition, almost all PLS neurons showed duration-independent PLS to FM pulses, but the same units exhibited duration-dependent PLS to tone pulses. Taken together, when compared to tone pulses, FM stimuli can provide more reliable estimates of target range.


Echolocation Target ranging Frequency modulation Oscillation First-spike latency 



This research is supported by a grant from the National Institute on Deafness and Communication Disorders of the NIH (R01DC04998). We thank Wenyu Lin and Karla Melendez for their comments on earlier versions of this manuscript.


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Copyright information

© Springer-Verlag 2006

Authors and Affiliations

  • Xinming Wang
    • 1
  • Alexander V. Galazyuk
    • 1
    • 2
  • Albert S. Feng
    • 1
  1. 1.Department of Molecular and Integrative Physiology and Beckman InstituteUniversity of IllinoisUrbanaUSA
  2. 2.Northeastern Ohio University College of MedicineRootstownUSA

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