Hearing in helmeted guineafowl (Numida meleagris): audiogram from 2 Hz to 10 kHz and localization acuity for brief noise bursts.

Behavioral hearing thresholds and noise localization acuity were determined using a conditioned avoidance/suppression procedure for three Helmeted guineafowl (Numida meleagris). The guineafowl responded to frequencies as low as 2 Hz at 82.5 dB SPL, and as high as 8 kHz at 84.

Hearing in African pygmy hedgehogs (Atelerix albiventris): audiogram, sound localization, and ear anatomy.

The behavioral audiogram and sound localization performance, together with the middle and inner ear anatomy, were examined in African pygmy hedgehogs Atelerix albiventris. Their auditory sensitivity at 60 dB SPL extended from 2 to 46 kHz, revealing a relatively narrow hearing range of 4.6 octaves, with a best sensitivity of 21 dB at 8 kHz.

Hearing in Indian peafowl (Pavo cristatus): sensitivity to infrasound.

Despite the excitement that followed the report of infrasound sensitivity in pigeons 40 years ago, there has been limited followup, with only eleven species of birds having auditory thresholds at frequencies below 250 Hz. With such sparse data on low-frequency hearing, there is little understanding of why some birds hear very low frequencies while others do not. To begin to expand the phylogenetic and ecological sample of low-frequency hearing in birds, we determined the behavioral audiogram of the Indian peafowl, Pavo cristatus.

Hearing and sound localization in Cottontail rabbits, Sylvilagus floridanus.

Cottontail rabbits represent the first wild species of the order of lagomorphs whose hearing abilities have been determined. Cottontails, Sylvilagus floridanus, evolved in the New World, but have spread worldwide. Their hearing was tested behaviorally using a conditioned-avoidance procedure.

Bats are unusually insensitive to brief low-frequency tones.

Bats use brief calls for echolocation, suggesting that they might be more sensitive to brief sounds than non-echolocating mammals. To investigate this possibility, absolute thresholds for brief tones were determined for four species of bats: The Common vampire bat (Desmodus rotundus) and the Greater spear-nosed bat (Phyllostomus hastatus), both of which use frequency-modulated calls, the Egyptian fruit bat (Rousettus aegyptiacus), an echolocator that uses tongue-clicks rather than laryngeal calls, and the Dog-faced fruit bat (Cynopterus brachyotis), a non-echolocating species. Norway rats and a human were tested for comparison using the same acoustic stimuli.

Normal audiogram but poor sensitivity to brief sounds in mice with compromised voltage-gated sodium channels (Scn8a).

The Scn8a mutation of the gene for sodium channels at the nodes of Ranvier slows nerve conduction, resulting in motor abnormalities. This mutation is also associated with loss of spontaneous bursting activity in the dorsal cochlear nucleus. However initial tests of auditory sensitivity in mice homozygous for this mutation, using standard 400-ms tones, demonstrated normal hearing sensitivity.

Budgerigars (Melopsittacus undulatus) do not hear infrasound: the audiogram from 8 Hz to 10 kHz.

The pure-tone thresholds of three budgerigars were determined from 8 Hz to 10 kHz. At a level of 60 dB sound pressure level (re 20 μN/m), their hearing range extends 6.6 octaves from 77 Hz to 7.

Sound localization in common vampire bats: acuity and use of the binaural time cue by a small mammal.

Passive sound-localization acuity and the ability to use binaural time and intensity cues were determined for the common vampire bat (Desmodus rotundus). The bats were tested using a conditioned suppression/avoidance procedure in which they drank defibrinated blood from a spout in the presence of sounds from their right, but stopped drinking (i.e.

Hearing in alpacas (Vicugna pacos): audiogram, localization acuity, and use of binaural locus cues.

Behavioral audiograms and sound localization abilities were determined for three alpacas (Vicugna pacos). Their hearing at a level of 60 dB sound pressure level (SPL) (re 20 μPa) extended from 40 Hz to 32.8 kHz, a range of 9.

Audiogram of the chicken (Gallus gallus domesticus) from 2 Hz to 9 kHz.

The pure-tone thresholds of four domestic female chickens were determined from 2 Hz to 9 kHz using the method of conditioned suppression/avoidance. At a level of 60 dB sound pressure level (re 20 μN/m(2)), their hearing range extends from 9.1 Hz to 7.

Hearing in American leaf-nosed bats. IV: the Common vampire bat, Desmodus rotundus.

We behaviorally determined the audiograms of three Common vampire bats (Phyllostomidae, Desmodus rotundus), a species specialized to exist exclusively on blood. The bats were trained to respond to pure tones in a conditioned suppression/avoidance procedure for a blood reward and a mild punisher for failures to detect the tones. Common vampire bats have a hearing range from 716 Hz to 113 kHz at a level of 60 dB.

Conditioned suppression/avoidance as a procedure for testing hearing in birds: the domestic pigeon (Columba livia).

Although the domestic pigeon is commonly used in learning experiments, it is a notoriously difficult subject in auditory psychophysical experiments, even those in which it need only respond when it detects a sound. This is because pigeons tend to respond in the absence of sound-that is, they have a high false-positive rate-which makes it difficult to determine a pigeon's audiogram. However, false positives are easily controlled in the method of conditioned suppression/avoidance, in which a pigeon is trained to peck a key to obtain food and to stop pecking whenever it detects a sound that signals impending electric shock.

Use of binaural cues for sound localization in two species of Phyllostomidae: the Greater spear-nosed bat (Phyllostomus hastatus) and the Short-tailed fruit bat (Carollia perspicillata).

Unlike humans, not all mammals use both of the binaural cues for sound localization. Whether an animal uses these cues can be determined by testing its ability to localize pure tones; specifically, low frequencies are localized using time-difference cues, and high frequencies are localized using intensity-difference cues. We determined the ability to use binaural cues in 2 New World bats, Phyllostomus hastatus, large omnivores, and Carollia perspicillata, small frugivores, by testing their tone-localization ability using a conditioned avoidance procedure.

Use of binaural cues for sound localization in large and small non-echolocating bats: Eidolon helvum and Cynopterus brachyotis.

The authors determined the ability of two old-world non-echolocating bats, Eidolon helvum and Cynopterus brachyotis, to use binaural time and intensity difference cues for localization. The bats were trained to localize pure tones throughout most of their hearing range from loudspeakers located 30 degrees to the left and right of midline. Both species easily localized high frequency tones, indicating they could use the interaural intensity difference cue.

Laboratory rats (Rattus norvegicus) do not use binaural phase differences to localize sound.

The ability of Norway rats to use binaural time- and intensity-difference cues to localize sound was investigated by determining their ability to localize pure tones from 500 Hz to 32 kHz. In addition, their ability to use the binaural time cues present in the envelope of a signal was determined by presenting them with a 1-kHz tone that was amplitude modulated at either 250 or 500 Hz. Although the animals were easily able to localize tones above 2 kHz, indicating that they could use the binaural intensity-difference cue, they were virtually unable to localize the lower-frequency stimuli, indicating that they could not use the binaural phase (time) cue.

Comparison of behavioral and auditory brainstem response measures of threshold shift in rats exposed to loud sound.

The purpose of this study was to determine how closely the auditory brainstem response (ABR) can estimate sensorineural threshold shifts in rats exposed to loud sound. Behavioral and ABR thresholds were obtained for tones or noise before and after exposure to loud sound. The results showed that the ABR threshold shift obtained with tone pips estimated the initial pure-tone threshold shifts to within +/-5 dB 11% of the time and the permanent pure-tone threshold shifts 55% of the time, both with large errors.

Behavioral assessment of hearing in mice--conditioned suppression.

The method of conditioned suppression described in this unit involves training a thirsty mouse to make steady contact with a waterspout in order to receive a slow, but steady trickle of water and then pairing a sound with mild electric shock delivered through the spout. The mouse quickly learns to avoid the shock by breaking contact with the spout whenever it detects the sound. This suppression of drinking is then used to indicate that the animal detected the sound.

Tinnitus and hearing loss in hamsters (Mesocricetus auratus) exposed to loud sound.

Hamsters were trained to go left and right to sounds on their left and right sides, respectively. Silent trials were occasionally given in which no sound was presented. Hamsters exposed to a loud 2- or 10-kHz tone in 1 ear often shifted their responding on the silent trials to the side of the exposed ear, suggesting that they perceived a sound in that ear (i.

Hearing in American leaf-nosed bats. III: Artibeus jamaicensis.

We determined the audiogram of the Jamaican fruit-eating bat (Phyllostomidae: Artibeus jamaicensis), a relatively large (40-50 g) species that, like other phyllostomids, uses low-intensity echolocation calls. A conditioned suppression/avoidance procedure with a fruit juice reward was used for testing. At 60 dB SPL the hearing range of A.

Hearing in American leaf-nosed bats. II: Carollia perspicillata.

We determined the audiograms of two short-tailed fruit bats (Carollia perspicillata), 18-g phyllostomids from Central and South America. For testing, we used a conditioned suppression/avoidance procedure with a fruit juice reward. At an intensity of 60 dB SPL, the hearing of C.

Behavioral audiograms of homozygous med(J) mutant mice with sodium channel deficiency and unaffected controls.

Complete behavioral audiograms were determined for med(J) mice (F1 offspring of C57BL/6JxC3HeB/FeJ) and unaffected controls from the same F1 background. The med(J) mutation results in greatly reduced levels of Scn8a voltage-gated sodium channels, which causes abnormal conduction of action potentials throughout the nervous system and may account for the virtual absence of spontaneous bursting activity in the dorsal cochlear nucleus. The med(J) mice also have tremors, display dystonic postures, and drag their hind legs.

Hearing in American leaf-nosed bats. I: Phyllostomus hastatus.

We determined the audiogram of Phyllostomus hastatus (the greater spear-nosed bat), a large, omnivorous American leaf-nosed bat native to Central and South America. A conditioned suppression/avoidance procedure with a fruit juice reward was used for testing. At an intensity of 60 dB sound pressure level (SPL re 20 microN/m(2)), the hearing range of P.

Cross-modal neuroplasticity in neonatally enucleated hamsters: structure, electrophysiology and behaviour.

Potential auditory compensation in neonatally bilaterally enucleated Syrian hamsters was explored anatomically, electrophysiologically and behaviourally. Gross morphology of the visual cortex appeared normal and no obvious cytoarchitectural malformation was discerned. However, enucleation induced a significant increase in the spontaneous firing rate of visual cortex cells.