title: Sound-evoked oscillation and paradoxical latency shift in the inferior colliculus neurons of the big fruit-eating bat, Artibeus jamaicensis.
abstract: Frequency tuning, temporal response pattern and latency properties of inferior colliculus neurons were investigated in the big fruit-eating bat, Artibeus jamaicensis. Neurons having best frequencies between 48-72 kHz and between 24-32 kHz are overrepresented. The inferior colliculus neurons had either phasic (consisting in only one response cycle at all stimulus intensities) or long-lasting oscillatory responses (consisting of multiple response cycles). Seventeen percent of neurons displayed paradoxical latency shift, i.e. their response latency increased with increasing sound level. Three types of paradoxical latency shift were found: (1) stable, that does not depend on sound duration, (2) duration-dependent, that grows with increasing sound duration, and (3) progressive, whose magnitude increases with increasing sound level. The temporal properties of paradoxical latency shift neurons compare well with those of neurons having long-lasting oscillatory responses, i.e. median inter-spike intervals and paradoxical latency shift below 6 ms are overrepresented. In addition, oscillatory and paradoxical latency shift neurons behave similarly when tested with tones of different durations. Temporal properties of oscillation and PLS found in the IC of fruit-eating bats are similar to those found in the IC of insectivorous bats using downward frequency-modulated echolocation calls.
authors.affiliation: Department of Animal and Human Biology, University of Havana, Havana, Cuba. julio.cesar@daad-alumni.de
authors.forename: Julio C
authors.initials: JC
authors.lastname: Hechavarría
authors.forename: Ariadna T
authors.initials: AT
authors.lastname: Cobo
authors.forename: Yohami
authors.initials: Y
authors.lastname: Fernández
authors.forename: Silvio
authors.initials: S
authors.lastname: Macías
authors.forename: Manfred
authors.initials: M
authors.lastname: Kössl
authors.forename: Emanuel C
authors.initials: EC
authors.lastname: Mora
mesh_terms: D000161:Acoustic Stimulation; D000818:Animals; D001307:Auditory Perception; D002685:Chiroptera / Q000502:physiology*; D004455:Echolocation; D005260:Female; D007245:Inferior Colliculi / Q000166:cytology / Q000502:physiology*; D008297:Male; D009474:Neurons / Q000502:physiology*; D011930:Reaction Time; D012815:Signal Processing, Computer-Assisted; D013018:Sound Spectrography; D013997:Time Factors; D013998:Time Perception