42 research outputs found
Noise-Induced Frequency Modifications of Tamarin Vocalizations: Implications for Noise Compensation in Nonhuman Primates
<div><p>Previous research suggests that nonhuman primates have limited flexibility in the frequency content of their vocalizations, particularly when compared to human speech. Consistent with this notion, several nonhuman primate species have demonstrated noise-induced changes in call amplitude and duration, with no evidence of changes to spectral content. This experiment used broad- and narrow-band noise playbacks to investigate the vocal control of two call types produced by cotton-top tamarins (<i>Saguinus Oedipus</i>). In ‘combination long calls’ (CLCs), peak fundamental frequency and the distribution of energy between low and high frequency harmonics (<i>spectral tilt</i>) changed in response to increased noise amplitude and bandwidth. In chirps, peak and maximum components of the fundamental frequency increased with increasing noise level, with no changes to spectral tilt. Other modifications included the Lombard effect and increases in chirp duration. These results provide the first evidence for noise-induced frequency changes in nonhuman primate vocalizations and suggest that future investigations of vocal plasticity in primates should include spectral parameters.</p></div
Representative CLCs produced by subject Mulva during a) control and b) treatment A trials illustrating changes to spectral tilt.
<p>All whistles from a) have strong fundamental frequencies and maximum energy in the 2<sup>nd</sup> harmonic, while in b) the first whistle has a very faint fundamental frequency at approximately 2 kHz, and peak frequencies for all whistles occur in the 4<sup>th</sup> harmonics. Reduced energy in the fundamental frequency is also apparent in the second and third whistles (spectrogram parameters: 1024 point Hamming window, 75% overlap, 11.7 Hz frequency resolution).</p
Diagram of experimental setup.
<p>Letters indicate equipment placement; M = microphone; C = video camera; NS = speaker presenting noise stimulus; ES = speaker presenting elicitation stimulus.</p
Spectrograms of CLC (a) and chirp (b) vocalizations with measured frequency characteristics indicated.
<p>This CLC consists of one chirp and four whistle syllables. All measurements of CLCs were made on the call as a whole and the individual syllables within the call (not shown); measurements of chirps were made from the fundamental frequency (first harmonic). Note that peak frequency measurements for all syllables, fundamental frequencies, and whole calls were taken automatically from the selection spectrum view in Raven 1.4 (not shown).</p
Noise stimuli.
<p>Spectrograms (1024 point Hamming window, 75% overlap, 11.7 Hz frequency resolution) of noise playback stimuli recorded during trials. Treatments A–C had a bandwidth of 5 kHz. Treatments D–F had a 10 kHz bandwidth. Harmonic structure is due to frequency response of the playback system.</p
Average chirp duration (ms).
<p>Control values are were averaged over all six control trials for each subject; treatment values were averages of each chirp produced by a subject during the named treatment trial. Bart did not produce chirps during treatments A and F.</p><p>Average chirp duration (ms).</p
Average CLC source levels vs. noise level for all 6 noise bandwidth/level combinations.
<p>Treatments A, B, and C had 5 kHz bandwidth; treatments D, E, and F had 10 kHz bandwidth. The top, middle, and bottom rows indicate high, medium, and low noise amplitudes, respectively. Panels are arranged by noise level (rows) and bandwidth (columns). Triangles, squares, and stars represent Mulva, Jerry, and Bart, respectively. Note that call source level never decreases between control (42 dB re 20 μPa noise level) and treatment trials.</p
Decreased expression of laminin α3, tissue factor and N-cadherin in human bronchial epithelial cells incubated in old versus young lung matrix.
<p><b>A)</b> Gene expression (qRT-PCR) of hBECs after 1 week incubation in young and old decellularized B10.BR mouse lung matrix. N = 3/group; *p<0.05 for 1 yo vs 3 wo. Data are normalized against hBECs grown on tissue culture plastic. UD = undetected. <b>B)</b> Immunofluorescence staining shows decreased human Lama3 deposition (green) by hBECs infused in 1yo decellularized lung matrix compared to 3wo matrix. Non-infused, age-matched, decellularized lungs are shown as controls. DAPI nuclear staining is shown in blue. Distal alveolar regions are shown. Magnification 200X. Images are 1 representative of 3 lung matrices per condition.</p
Differentially expressed ECM proteins in young versus old decellularized murine lungs identified by iTRAQ.
<p>Differentially expressed ECM proteins in young versus old decellularized murine lungs identified by <u>iTRAQ</u>.</p
Differential expression of matrix-associated genes and proteins in young versus old mouse lungs.
<p><b>A</b>) Comparison of ECM component levels in native and decellularized lungs of different aged B10.BR mice. Statistical comparisons were done only between ages within a treatment group, not between treatment groups. *p<0.05 comparing ages indicated by bar. N = 6 for all groups. For hydroxyproline, **p<0.05 for 4 do vs. all other ages in treatment group; for elastin, **p<0.05 for 3 mo decell vs. other decell ages; for total laminin, **p<0.05 for 4 do decell vs. other decell ages, ***p<0.05 for 3 wo decell vs. other decell ages; for vitronectin, **p<0.05 for 4 do decell vs. other decell ages; for sulfated Glycosaminoglycans, **p<0.05 for 4 do or 3 mo non-decell vs. 3 wo or 1 yo non-decell, ***p<0.05 for 3 wo or 3 mo decell vs. 4 do and 1 yo decell. Abbreviations used: do = day old, wo = week old, mo = month old, yo = year old. <b>B)</b> Gene expression in native lungs from young and old B10.BR mice as assessed by qRT-PCR. N = 6/group; *p<0.05 old vs young. Values are normalized to a representative 3 wo mouse. <b>C)</b> Immunofluorescence images of mouse Lama3, Lama4, fibronectin and vitronectin staining of decellularized lungs from 3-week vs 1-year old B10.BR mice. Magnification 200X. Images are 1 representative of 3 decellularized lungs per group.</p