Publications by authors named "Heffner R"

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.

View Article and Find Full Text PDF

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.

View Article and Find Full Text PDF

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.

View Article and Find Full Text PDF

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.

View Article and Find Full Text PDF

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.

View Article and Find Full Text PDF

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.

View Article and Find Full Text PDF

Branstetter and his colleagues present the audiograms of eight killer whales and provide a comprehensive review of previous killer whale audiograms. In their paper, they say that the present authors have reported a relationship between size and high-frequency hearing but that echolocating cetaceans might be a special case. The purpose of these comments is to clarify that the relationship of a species' high-frequency hearing is not to its size (mass) but to its "functional interaural distance" (a measure of the availability of sound-localization cues).

View Article and Find Full Text PDF

Background: Statins have well-known benefits in the prevention of cardiovascular disease, however, 7-29% of patients develop muscle side effects and up to 0.5% develop severe symptoms. Mitochondrial dysfunction has been associated with severe statin-induced myopathy (SM); however, there is a paucity of systematic studies in affected individuals.

View Article and Find Full Text PDF

The coordination of macrophage polarization is essential for the robust regenerative potential of skeletal muscle. Repair begins with a phase mediated by inflammatory monocytes (IM) and proinflammatory macrophages (M1), followed by polarization to a proregenerative macrophage (M2) phenotype. Recently, regulatory T cells (Tregs) were described as necessary for this M1 to M2 transition.

View Article and Find Full Text PDF

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.

View Article and Find Full Text PDF
Article Synopsis
  • The cochlear nucleus is a crucial part of the auditory system, processing sound information from the cochlea and providing input to other auditory areas.
  • Detailed size measurements of its subdivisions (AVCN, PVCN, and DCN) were taken in 15 rodent species and a few others, revealing that while most regions are identifiable, some like the DCN layers in mountain beavers were unique.
  • Interestingly, the mountain beaver and pocket gopher showed larger relative sizes of certain cochlear nucleus regions, while most species' sizes didn't consistently relate to their lifestyles or hearing.
View Article and Find Full Text PDF

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.

View Article and Find Full Text PDF

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.

View Article and Find Full Text PDF

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.

View Article and Find Full Text PDF

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.

View Article and Find Full Text PDF

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.

View Article and Find Full Text PDF

Background: Hospital discharges are vulnerable periods for patient safety, especially in teaching hospitals where discharges are done by residents with competing demands. We sought to assess whether embedding a nurse practitioner on a medical team to help physicians with the discharge process would improve communication, patient follow-up, and hospital reutilization.

Methods: A 5-month randomized controlled trial was conducted on the medical service at an academic tertiary-care hospital.

View Article and Find Full Text PDF

Introduction: Using experimental autoimmune encephalomyelitis (EAE), an animal model for multiple sclerosis (MS), the objective of this study was to examine the effect of phytosterol (PS) administration on inflammation-based EAE development.

Methods: Female SJL mice were orally administered PS prior to disease induction and maintained throughout the experiment. EAE was induced with antigenic peptide (PLP(131-155)).

View Article and Find Full Text PDF

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.

View Article and Find Full Text PDF

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.

View Article and Find Full Text PDF

The high-field superconducting state in CeCoIn(5) has been studied by transverse field muon spin rotation measurements with an applied field parallel to the crystallographic c axis close to the upper critical field mu(0)H(c2) = 4.97 T. At magnetic fields mu(0)H > or = 4.

View Article and Find Full Text PDF