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  • Comparative Studies. Non-European Languages/Literatures  (9)
  • 1
    Online Resource
    Online Resource
    Acoustical Society of America (ASA) ; 1997
    In:  The Journal of the Acoustical Society of America Vol. 102, No. 5_Supplement ( 1997-11-01), p. 3188-3188
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 102, No. 5_Supplement ( 1997-11-01), p. 3188-3188
    Abstract: Aspects of auditory processing related to temporal and spectral resolution were investigated in 50 adult subjects (aged 18-58) with varying reading abilities. The tests administered included tone detection, tone frequency discrimination, tone sequencing, interval discrimination, and gap detection. Tones were either long (250 ms) or short (20 ms) and ranged in frequency between 600 and 1400 Hz. Detection and frequency discrimination tasks were given in the clean and in a masking context, in which tones were followed by 300-ms bandpass noise. Thresholds were determined using an adaptive procedure. Backward masking interferences for short tones, as well as interval and frequency discrimination limens were substantially elevated for most poor readers, and were correlated with one another. Three-tone sequencing and short-tone frequency discrimination in a masking context were especially strongly correlated with single-word reading ability. Gap detection thresholds did not correlate with other tasks or with reading ability. In sum, spectral-temporal auditory processing resolution appears to be related to reading ability, possibly via an acoustically based deficit in phonetic development. These findings raise the question of whether nonspeech acoustic training can be used to improve adults’ reading ability. [Work supported by Scientific Learning Corporation.]
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    RVK:
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 1997
    detail.hit.zdb_id: 1461063-2
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  • 2
    Online Resource
    Online Resource
    Acoustical Society of America (ASA) ; 2002
    In:  The Journal of the Acoustical Society of America Vol. 112, No. 5_Supplement ( 2002-11-01), p. 2314-2314
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 112, No. 5_Supplement ( 2002-11-01), p. 2314-2314
    Abstract: Auditory cortex is thought to play a critical role in the processing of species-specific vocalizations and other acoustically complex sounds. Although evolutionary processes strongly constrain cortical sensitivities to sound, cortical processing is not fixed by biology, but rather is shaped by the auditory experiences of each individual. Auditory cortical neurons in adult rats respond selectively to spectrotemporal features of complex sounds. These selective responses are predictive of rats’ behaviorally measured perceptual sensitivities. With extensive training, the abilities of rats to discriminate frequency-modulated sounds improve. Recordings from cortical neurons in trained rats show increased sensitivities to features of the sounds used in training. These results demonstrate that discrimination training with biologically irrelevant complex sounds can change how cortical neurons process those sounds. Changes in cortical processing of complex sounds can also be induced by controlling activity in neuromodulatory neurons while a rat experiences the sounds. Pairing the presentation of complex sounds with electrical stimulation of basal forebrain neurons radically changes cortical sensitivities to spectrotemporal features of those sounds. These data suggest that auditory cortical representations of acoustic events can be flexibly adjusted throughout the lifespan of an individual rate. Presumably, similar or greater flexibility exists in animals with more sophisticated auditory systems.  
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    RVK:
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2002
    detail.hit.zdb_id: 1461063-2
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  • 3
    Online Resource
    Online Resource
    Acoustical Society of America (ASA) ; 2000
    In:  The Journal of the Acoustical Society of America Vol. 107, No. 5_Supplement ( 2000-05-01), p. 2835-2835
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 107, No. 5_Supplement ( 2000-05-01), p. 2835-2835
    Abstract: Spectral variations over time are a common characteristic of naturally occurring sounds. They constitute a prevalent feature in communication signals in several species. Studies of mammals have shown that auditory cortex neurons respond to single frequency-modulated (FM) sweeps and that most responses are selective for sweep direction and/or rate. Researchers have also used trains of FM sweeps to estimate spectrotemporal receptive fields in auditory cortex. In the present study, microelectrode recordings were used to explore how the auditory cortex responds to trains of FM sweeps in anesthetized rats. Maps of 20–60 penetrations were made for each subject. Sweep frequencies ranged from 1–16 kHz with FM rates ranging from 4–24 octaves/s and repetition rates from 2–24 sweeps/s. Both down-sweeps and up-sweeps were presented. Neuronal responses were analyzed in terms of onset, offset, oscillatory and directionally selective properties. Several types of responses predominated. Most units responded to sound onset. In contrast, responses to signal offsets were rare. Oscillatory responses were typically evoked only for repetition rates less than 12 sweep/s. Directionally selective responses were limited to these rates. These results indicate that oscillatory responses in the auditory cortex are limited to low repetition rate stimuli, and that directional selectivity depends on repetition rate. [Work supported by NSF.]
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    RVK:
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2000
    detail.hit.zdb_id: 1461063-2
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  • 4
    Online Resource
    Online Resource
    Acoustical Society of America (ASA) ; 2003
    In:  The Journal of the Acoustical Society of America Vol. 114, No. 6 ( 2003-12-01), p. 3412-3422
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 114, No. 6 ( 2003-12-01), p. 3412-3422
    Abstract: Auditory neurobiology has benefited significantly from ethological approaches using acoustic communication signals. Developing an ethological model in a genetically manipulable system such as the mouse would enhance the ability to investigate the processing, learning, and recognition of sounds. Characterizing the basic acoustic structure of mouse vocalizations would help lay a foundation for such a future study. Towards this goal, ultrasound vocalizations emitted by isolated mouse pups and pairs of adult males and females have been digitally recorded and examined. Previous work suggests that these calls may have communicative significance. An analysis of the natural variability in their spectral content, median frequency, duration, and repetition period reveals acoustic structure that could be used for recognizing the calls. Other parameters, like the rate of frequency modulation, may also be informative, but have not been examined. Pup isolation calls develop systematically between postnatal day 5 and 12 towards a more stereotyped vocalization—contracting from a wide range of values into narrower clusters of frequency and duration, and shifting from longer to shorter repetition periods. Most significantly, pup isolation and adult encounter calls fall into two distinct spectral and temporal categories, making it possible for a receiver to acoustically distinguish between them, and to potentially categorically perceive them along those dimensions.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    RVK:
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2003
    detail.hit.zdb_id: 1461063-2
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  • 5
    Online Resource
    Online Resource
    Acoustical Society of America (ASA) ; 2002
    In:  The Journal of the Acoustical Society of America Vol. 112, No. 5_Supplement ( 2002-11-01), p. 2286-2286
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 112, No. 5_Supplement ( 2002-11-01), p. 2286-2286
    Abstract: Primates engage in auditory behaviors under a broad range of signal to noise conditions. In this study, optimal linear receptive fields were measured in alert primate A1 in response to stimuli that vary in spectrotemporal density. As the random tone pip density increased, selective A1 excitatory receptive fields systematically changed. Receptive field sensitivity, expressed as the expected change in firing rate after a tone pip onset, decreased by an order of magnitude. Spectral selectivity more than doubled. Inhibitory subfields, which were rarely recorded at low sound densities, emerged at higher sound densities. The ratio of excitatory to inhibitory population strength changed from 14.4:1 to 1.4:1. At low sound densities, the sound associated with the evocation of an action potential from an A1 neuron was broad in spectrum and time. At high sound densities, a spike-evoking sound was more likely to be a spectral or temporal edge, and was narrower in both time and frequency range. Prediction experiments were performed to validate the assumption that linear receptive fields were representative of neural responses at high noise densities. The auditory context alters A1 responses across multiple parameter spaces; this presents a challenge for reconstructing neural codes.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    RVK:
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2002
    detail.hit.zdb_id: 1461063-2
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  • 6
    Online Resource
    Online Resource
    Acoustical Society of America (ASA) ; 1995
    In:  The Journal of the Acoustical Society of America Vol. 97, No. 5_Supplement ( 1995-05-01), p. 3236-3236
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 97, No. 5_Supplement ( 1995-05-01), p. 3236-3236
    Abstract: An important property of the cerebral cortex is its ability to reorganize itself in response to changing sensory environment throughout life. Representational ‘‘maps’’ of skin surfaces in the primary somatosensory cortex (SI) are remodeled after many forms of input alteration. Two questions were addressed in our recent plasticity experiment: Under what specific conditions are spatially distributed and time-varying sensory inputs (a) integrated, or (b) segregated in their representations by the dynamic mechanisms underlying cortical function? The results showed that the topographic map of skin surfaces in SI was dramatically remodeled in adult owl monkeys trained to discriminate two tactile stimuli applied to distal and proximal segments of their fingers in alternation. Subsequent mapping of area 3b revealed neural responses with either distal or proximal multiple-digit receptive fields, reflecting cortical integration of inputs from temporally coincidentally excited skin surfaces. By contrast, the cortical representations of temporally noncoincidentally stimulated skin surfaces were segregated from each other. These findings directly demonstrate that for learning induced plastic changes in cortical topographic maps, afferent input integration and segregation are dependent on stimulus coincidence, and that regularly practiced hand use results in a representation of its sensory surfaces in the brain that reflects that specific use.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    RVK:
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 1995
    detail.hit.zdb_id: 1461063-2
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  • 7
    Online Resource
    Online Resource
    Acoustical Society of America (ASA) ; 1980
    In:  The Journal of the Acoustical Society of America Vol. 68, No. S1 ( 1980-11-01), p. S19-S19
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 68, No. S1 ( 1980-11-01), p. S19-S19
    Abstract: Psychophysical evidence strongly suggests that there is a central neural pattern of representation of sound frequencies; and that the overall pitch of any sound is a function of this central pattern. Physiological studies on the discharges of auditory nerve fibers as a function of cochlear location, and psychophysical studies employing controlled electrical stimulation of the auditory nerve array in man strongly indicate that the spectral composition of complex sounds is not extracted from either discharge rate versus position profiles across the auditory nerve array (the “cochlear place”), or by measuring input discharge periodicities per se. It is hypothesized that spectral components of sounds are extracted from the relative timing of discharges of auditory nerve fibers from separated locations along the auditory nerve array. To extract a spectral representational pattern with broad dynamic range, comparator neurons must detect the synchronicity of arrival of input from separated basilar membrane locations with a resolution of 10–20 μs. It is hypothesized that this extraction is effected by the neurons of the medial superior olive, which operate as monaural as well as binaural time comparators. Psychophysical and physiological data supporting testable predictions of this hypothesis will be reviewed. [Work supported by NIH Contract N01-NS-7-2367 and NIH Grant NS-11804.]
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    RVK:
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 1980
    detail.hit.zdb_id: 1461063-2
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  • 8
    Online Resource
    Online Resource
    Acoustical Society of America (ASA) ; 2000
    In:  The Journal of the Acoustical Society of America Vol. 107, No. 5_Supplement ( 2000-05-01), p. 2835-2836
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 107, No. 5_Supplement ( 2000-05-01), p. 2835-2836
    Abstract: Response characteristics of auditory cortex can be altered by repeatedly pairing sounds with basal forebrain stimulation [M. P. Kilgard and M. M. Merzenich, Science 279, 1714–1718 (1998)]. Although many neurons in auditory cortex respond most strongly to time-varying sounds, most studies of stimulation-induced plasticity have focused on changes in responses to tone pips. We examined stimulation-induced changes in neuronal sensitivities to frequency-modulated sweep trains (bandwidth=2–16 kHz, duration=1 s, sweep rates=4–24 octaves/s, repetition rates=2–24 sweeps/s). Adult rats received electrical stimulation of basal forebrain paired with 1–10 varieties of sweep trains, 300–500 times per day, for 9–16 days. Some sounds were presented in combination with bandlimited Gaussian noise. After stimulation, neuronal responses were recorded from 20–80 sites in the auditory cortex of each rat. The spectrotemporal sensitivities of auditory cortical neurons were dramatically altered in stimulated rats. Changes in response characteristics were not straightforwardly related to features of the sounds that had been paired with stimulation. Certain sounds that normally evoked responses correlated with sweep repetition rate in control rats tende d to evoke either aperiodic or uncorrelated periodic responses from neurons of stimulated rats. Current theories of auditory cortical plasticity do not account for these results. [Work supported by MBRS, NIMH, NSF.]
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    RVK:
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2000
    detail.hit.zdb_id: 1461063-2
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  • 9
    Online Resource
    Online Resource
    Acoustical Society of America (ASA) ; 1985
    In:  The Journal of the Acoustical Society of America Vol. 77, No. S1 ( 1985-04-01), p. S81-S81
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 77, No. S1 ( 1985-04-01), p. S81-S81
    Abstract: Two speech processing systems, a four-channel vocoder-based model and a single-channel model, were examined in a single patient. Five isolated, computer-generated vowels were presented in a closed-set paradigm and responses were plotted on a confusion matrix. With four-channel stimulation the overall score was 64% correct. The subject never confused vowels having a low-frequency second formant (F2) with high-frequency F2 items. In the single-channel configuration, the subject did not distinguish between low F2 and high F2 items and scored 29% overall. Consonant confusion matrices were generated for seven naturally produced VCV syllables. In the four-channel configuration the overall score was 70% correct. The nasal distinction was not made and some voicing errors were observed. In the single-channel case, the subject scored 27% correct. The stop-continuant distinction was not routinely made and most errors involved multiple distinctive features. Analysis of the processed speech items explain some of the confusions observed in the four-channel mode. [Work supported by NIH Grant NS-11804.]
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    RVK:
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 1985
    detail.hit.zdb_id: 1461063-2
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