Judith L. Lauter

Tonotopic organization in human auditory cortex revealed by positron emission tomography

Positron emission tomography (PET) was used to map alterations in local neuronal activity induced in human primary auditory cortex by pure-tone stimulation. Patterns of blood flow were observed in specific regions on the superior temporal plane showing systematic changes in activity depending on the frequency of a stimulating pure tone. The orientation of these regions agrees well with data for non-human primates.

Stimulus characteristics and relative ear advantages: A new look at old data

A recent report of a series of dichotic listening experiments [Lauter, J. Acoust. Soc. Am. 71, 701–707 (1982)] showed that although individual listeners differ in the ‘‘absolute ear advantage’’ shown for a given sound, there are patterns of ‘‘relative ear advantages’’ that are consistent across listeners. It was suggested that these patterns might provide a means of studying which features of test sounds are important in determining ear advantages. A survey of 12 earlier experiments, including a brief synopsis of procedures, results, and conclusions, followed by reanalysis of individual scores, shows that patterns of relative ear advantages were also present in earlier results, though obscured by an analysis that focused on the average listener. Examination of these patterns and the characteristics of sounds tested reveals a few acoustical features of sounds (e.g., event timing, bandwidth, number of dimensions changing with time) that seem to affect ear differences in a consistent way, from listener to li...

Individual differences in auditory electric responses: comparisons of between-subject and within-subject variability. V. Amplitude-variability comparisons in early, middle, and late responses.

Each of two groups of adult subjects was tested under a repeated-measures design (Lauter & Loomis, 1986, 1988; Lauter & Karzon, 1990a, b) for ABRs and one other set of responses: middle-latency responses (MLRs: 10 to 50 ms post-stimulus) from Group II (four females and four males), and late responses (50 to 300 ms post-stimulus) from Group I (four females and three males). A companion paper (Lauter & Karzon, 1990b) presents data comparing and contrasting the patterns of relative variability of waveform-peak latency observed in middle-latency, late responses, and the ABR data previously reported. This paper presents amplitude results for the same data sets. Our findings indicate that, as we have reported previously, with regard to between-subject vs. within-subject variability of peak parameters of auditory EP waveforms, normal adult subjects are more consistent when compared with themselves than when compared with each other. This is true at all auditory EP levels tested, from brainstem to cortex, and is observed in both amplitude and latency data, in spite of the fact that the actual values of amplitude-stability measures are an order of magnitude smaller than for latency stability.

Processing asymmetries for complex sounds : comparisons between behavioral ear advantages and electrophysiological asymmetries based on quantitative electroencephalography

This experiment extends our earlier work on individual differences in ear advantages for complex sounds (Lauter 1982, 1983, 1984) to examine the results of combined behavioral and qEEG testing in the same subjects. Results include: (1) between-subject differences in absolute values together with between-subject agreements in terms of relative values, observed both for ear advantages (EAs) and hemisphere advantages (HAs); (2) within-subject agreement between behavioral (EAs) and physiological (HAs) measures of asymmetries; and (3) preliminary findings related to the interpretation of qEEG asymmetry data, such as the influence of hand movements on auditory-cortex qEEG recordings, and persistence of activation effects in which asymmetries evoked during a stimulation condition may be reflected in resting asymmetries observed during a subsequent control condition.

Human Auditory Physiology Studied with Positron Emission Tomography

Although the past 40 years have seen significant progress in our understanding of the organization of sensory nervous systems in a number of animals, access to the details of human sensory CNS structure and function has been hampered by the lack of noninvasive, high-resolution technology. However, within the last decade, a number of new devices have appeared that provide relatively noninvasive access to the human brain: e.g. CT and MRI for anatomical imaging, and MEG, BEAM, and PET for topographic physiological studies.

Contralateral interference and ear advantages for identification of three-element patterns

Recent experience with attempts to test relatively simple patterns such as three-tone sequences in a traditional dichotic-listening paradigm indicates that when such sequences are used for both target and contralateral interference, performance tends to be low in both ears and not useful for measuring or comparing ear advantages in various target conditions. It is reported that tests with a variety of sounds presented contralaterally to three-element patterns show that several such sounds can (1) allow performance in at least one ear to remain above floor values, (2) result in performance in at least one ear that is below ceiling, and (3) reveal ear advantages that are similar in direction and magnitude to those seen with the traditional dichotic paradigm.

Central auditory processing

Clinical audiology and hearing science have benefitted from tremendous recent advances in our knowledge of the function of the auditory periphery, but much less is known about processing in intact auditory pathways from lower brainstem into cortex and about the effect of central function and dysfunction on peripheral physiology and behavior. The array of noninvasive methods for monitoring and imaging the human brain that have been developed over the past two decades promises to give new insights into central auditory function. These techniques offer particular power as tools for studying connections among brain anatomy, physiology, and behavior expressed at the individual level. In this review, the applications of these noninvasive tools to the study of central auditory processing in humans in the past year are summarized. New methodologic developments that promise even more dramatic advances are discussed.

Speech as temporal pattern: A psychoacoustical profile

Abstract In visual representations of the acoustical signal of speech, such as the waveform or spectrogram, speech appears as a series of concatenated sequences of acoustical events, which vary in spectrum, amplitude and duration. The results of a variety of psychoacoustical experiments, from auditory fusion to temporal masking to studies of streaming, can be interpreted as relevant to discovering the auditory capabilities used in listening to these speech sequences. A sampling of such results serves to illustrate the connections between the psychoacoustics of speech and nonspeech, and to suggest guidelines for future work on non-speech temporal patterns, with the goal of a more complete psychophysics of complex sounds.

Dichotic identification of complex sounds

Ear advantages for sets of speech and nonspeech sounds were measured with four listeners. The speech sounds were: edited fragments of real stop CV syllables, synthetic versions of the full syllables, and six natural vowels. Nine sets of nonspeech sounds were tested; sets differed according to temporal variations in frequency, intensity, duration, and bandwidth. Task was always 6AFC, with a nonverbal response. Results bear on three issues: (1) methodology, (2) expression of results, and (3) the possible acoustical basis for ear advantages. (1) If appropriate methods are used and individual scores retained, ear advantages that are both large (40% difference between ears) and reliable over time can be obtained. (2) The categories of “left, right, and zero” are not sufficient to describe dichotic data; a continuum of ear advantage (25% REA is “more right” than 10% REA) is suggested, which allows comparisons of one listeners performance on several sounds, and comparisons among listeners. (3) Ear advantages se...

How can a video game cause panic attacks? 1. Effects of an auditory stressor on the human brainstem

The auditory brainstem response (ABR) was recorded during simultaneous binaural presentation of two types of sounds: (1) condensation clicks presented through in‐the‐ear earphones at 43.1/s, 60 dB nHL; and (2) recordings of breathing sounds, presented through supra‐aural headphones, at levels adjusted by participants to be equivalent to the clicks. In alternate blocks, the breathing sounds were either: (1) a recording of quiet breathing (blocks 1, 3, and 5) or (2) a recording of erratic (stressed) breathing (blocks 2 and 4). The erratic breathing was modeled on a video game soundtrack in which the character was represented as running, wounded, and frightened. Four 2048‐sweep ABR waveforms were collected in each of the five blocks, and the mean amplitude of ABR peak V was calculated over each set of four waveforms. Results indicate a significant decrease in the amplitude of ABR peak V during erratic breathing versus quiet breathing. Implications include (1) possible new evidence of the effect of selective attention on the ABR, (2) the potential for using auditory stressors to study the central physiology of emotional responses in humans, and (3) clues to physiological correlates of the effects of certain video games known to evoke panic attacks in susceptible players.