Janine M. Wotton

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To measure the directionality of the external ear of the echolocating bat, Eptesicus fuscus, the left or right eardrum of a dead bat was replaced by a microphone which recorded signals received from a sound source that was moved around the stationary head. The test signal was a 0.5-ms FM sweep from 100 kHz to 10 kHz (covering all frequencies in the bat's(More)
Measurements of external ear transfer functions in the echolocating bat Eptesicus fuscus have revealed a prominent spectral notch that decreases in center frequency (50 to 30-35 kHz) as elevation decreases [Wotton et al., J. Acoust. Soc. Am. 98, 1423-1445 (1995)]. To examine the influence of this notch, four Eptesicus were trained to discriminate between(More)
Big brown bats (Eptesicus fuscus) were trained to discriminate between vertical angles subtended by paired beads suspended from fishing line. Bats were rewarded for choosing the smaller of the two angles presented. The difference between the angles was changed systematically using a transformed up-down procedure and the bats' ability to detect the(More)
The information echolocating bats receive is a combination of the properties of the sound they emit and the sound they receive at the eardrum. Convolving the emission and the external ear transfer functions produces the full spectral information contained in the echolocation combination. Spatially dependent changes in the magnitude spectra of the emission,(More)
The acoustic information used by bats is produced by a combination of the properties of the sound emission and the reception at the eardrum. The potential localization cues used by bats can only be fully revealed when the magnitude spectra of the emission and the external ear are convolved to produce the echolocation combination magnitude spectra. The(More)
The external-ear transfer function for big brown bats (Eptesicus fuscus) contains two prominent notches that vary from 30 to 55 kHz and from 70 to 100 kHz, respectively, as sound-source elevation moves from -40 to +10 degrees. These notches resemble a higher-frequency version of external-ear cues for vertical localization in humans and other mammals.(More)
Anuran auditory nerve fibers (ANF) tuned to low frequencies display unusual frequency-dependent adaptation which results in a more phasic response to signals above best frequency (BF) and a more tonic response to signals below. A network model of the first two layers of the anuran auditory system was used to test the contribution of this dynamic peripheral(More)
Frogs rely upon vocal communication to advertise for potential mates, to defend territory and to alarm neighbors of danger. Cells in the auditory midbrain of an awake frog display tuning to the spectral energy present in calls based upon discharge rate and encode the temporal properties of calls in the timing of their discharges. This laboratory experiment(More)
Typically, individual neural cells operate on a millisecond time scale yet behaviorally animals reveal sub-microsecond acuity. Our model resolves this huge discrepancy by using populations of many widely tuned cells to attain sub-microsecond resolution in a temporal discrimination task. An echolocating bat uses its auditory system to locate objects and it(More)