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This study was designed to explore intensity preferences in music listening through an operant task which allowed subjects to alter loudness (intensity) levels for four selected frequency bands. Comparisons were made relating the effects of age, sex, frequency band, song, and presentation condition to intensity preferences and to the initial presentation volume. Six age groups comprising 18 through 90 year old subjects (N = 180) participated in the study. Subjects represented active and passive community music participants and were individually tested using six songs specifically chosen for their popular appeal. Initial audiometric evaluations indicated typical presbycusic changes as age increased. Subsequent loudness preferences were assessed for four frequency bands (110, 330, 1000, 3000 Hz) using a graphic frequency equalizer. Results obtained from equalizer settings indicated a significant difference between age groups. Subjects in the three younger age groups (18-53) preferred louder volume levels than did subjects in the oldest age group. Older subjects, with deteriorating hearing abilities, did not compensate by increasing the listening volume, while younger subjects with much better hearing did increase loudness levels. On the basis of this study it may be concluded that: (1) Older adults will generally prefer lower loudness levels than younger adults in music listening contexts. (2) An inverse relationship appears to exist between preferred loudness levels and auditory capabilities, with increased volume being paired with lower auditory threshold levels. (3) Older adults can be easily taught to use a graphic frequency equalizer and thereby create the possibility of increased enjoyment of music listening activities. / Source: Dissertation Abstracts International, Volume: 48-07, Section: A, page: 1693. / Thesis (Ph.D.)--The Florida State University, 1987.

The ventral division of the medial geniculate body (MGV) is the primary tonotopically-organized nucleus of the auditory thalamus. Previous studies have suggested a close association between the anatomical structure of the MGV and its observed functional organization, but direct correlative studies are lacking. In the present study, regional differences in the cytoarchitecture of the rabbit MGV were described. These different regions were shown to have distinct frequency organizations. The central portion of the rabbit MGV is characterized by a laminated cytoarchitecture that is formed from the orderly arrangement of highly-oriented neuronal cell bodies. In this region, there exists a steep frequency gradient that extends across the dorso-ventral axis of the nucleus, orthogonal to the cellular laminae. This frequency gradient is marked by a discontinuous and stepwise-progression of best frequency. In regions lacking a laminated cytoarchitecture, a steep frequency gradient is absent. In addition, the morphology and basic response properties of individual cells were studied with the juxtacellular labeling technique. Two morphological types of projection neurons as well as two types of putative interneurons were identified on the basis of dendritic thickness, cell soma size and spine morphology. Both types of tufted projection neurons had a variety of different response properties, but the Onset pattern and summation response to binaural stimulation predominate. Quantitative spatial analyses demonstrated that the dendritic fields of both types of tufted neurons are highly oriented. Further, for neurons within the laminated portion of the nucleus, the major axis of orientation of the dendritic fields are parallel to the cellular laminae and orthogonal to the frequency gradient. Departures from this orientation parallel changes in Nissl and functional architecture. A model is presented that correlates the discontinuous and step-wise frequency gradient in the nucleus with the size and morphology of dendritic fields. Lastly, three-dimensional reconstructions of anterogradely-labeled thalamocortical axons reveal a novel class of thalamocortical axon that has collaterals to both layer I as well as layers III/IV of primary auditory cortex; these layers were previously thought to have exclusively separate inputs. This novel class of axon is further evidence for multiple parallel channels from the MGV to AI.

Most data exploration tools are exclusively visual, failing to exploit the advantages of the human auditory system, and excluding students and researchers with visual disabilities. Sonification uses non-speech audio to create auditory graphs, which may address some limitations of visual graphs. However, almost no research has addressed how to create optimal sonifications. Three key research questions are: (1) What is the best sound parameter to use to represent a given data type? (2) Should an increase in the sound dimension (e.g., rising frequency) represent an increase or a decrease in the data dimension? (3) How much change in the sound dimension will represent a given change in the data dimension? Experiment 1 simply asked listeners which of two sounds represented something that was hotter, faster, etc. However, participants seemed not to make cognitive assessments of the sounds. I therefore proposed magnitude estimation (ME) as an alternative, less transparent, paradigm. Experiment 2 used ME with visual stimuli (lines and filled circles), replicating previous findings for perceptual judgments (length of lines, size of circles). However, judgments of conceptual data dimensions (i.e., the temperature, pressure, or velocity a given stimulus would represent) yielded slopes different from the perceptual judgments, indicating that the type of data being represented influences value estimation. Experiment 3 found similar results with auditory stimuli differing in frequency or tempo. Estimations of what temperature, pressure, velocity, size, or number of dollars a sound represented differed, indicating that both visual and auditory displays should be scaled according to the type of data being displayed. Experiment 4 presented auditory graphs and asked which of two data descriptions the sounds represented. Data sets based on the equations determined in Experiment 3 were preferred, providing validation of those slope values. Results also supported the use of the unanimity of mapping polarities as a measure of a mapping's effectiveness. Replication with different users and sounds is required to assess the reliability of the slopes. However, ME provides an excellent way to obtain a function relating conceptual data dimensions to display dimensions, which can be used to create more effective, appropriately scaled sonifications.

Currently available mathematical models of the eardrum are limited to low pressure levels owing to the assumption of linearity between stimulus (applied pressure) and response (eardrum displacement). In this work, the response of the cat eardrum to large static pressures is measured with a moire interferometer, and the data are modelled using the finite-element method. Experimental data indicate that eardrum response with a normal mobile malleus is nonlinear, asymmetric and hysteretic. Measurements with a fixed malleus permit investigation of eardrum behaviour without the confounding effects of the middle-ear ossicles. / Artifactual banding in measured displacement patterns is investigated by means of numerical simulations. Artifacts in moire interferometry arise from ignoring height-dependent fringe-plane spacing, modulation, reflectivity and magnification when reconstructing surface shape. Systematic errors induced by these assumptions are small: their effects are not apparent in shape measurements, but do show up as bands in displacement images. / The fixed-malleus data are modelled using the finite-element method to assess the importance of geometric nonlinearities at high pressure levels. Individualized finite-element models are created from shape data for each eardrum. Results indicate that geometric nonlinearity combined with nonuniform mechanical properties shows promise in describing eardrum response at high pressures.