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Results for “Pitch Discrimination”

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PubMed1978

The control of responding by auditory stimuli: interactions between different dimensions of the stimuli.

Sounds have position in addition to other dimensions, such as intensity and frequency. Position rapidly gains control of spatially contiguous responses and this may interfere with control of responding by other acoustic dimensions. These experiments investigated interference of a tone-noise discrimination by the discrimination of acoustic position. Squirrel monkeys were studied when responding was differentially reinforced in the presence of both spectral content (tone-noise) and positional differences between the stimuli, and when responding was differentially reinforced only in the presence of spectral differences. Under the first condition, responding rapidly came under the control of the position of the noise in the two monkeys tested. The position of the tone controlled responding in one monkey; in the second monkey, responding came under the control of the spectral content of the tone. Under the second condition, responding was initially under the control of the noise in all three monkeys tested. This persisted for the duration of the condition for two of the monkeys; in one monkey, responding came under the control of the spectral content of the noise. Under the second condition, responding was also initially under the control of the position of the tone for all monkeys, but control by spectral content of the tone relatively rapidly developed in two of three monkeys.

Acoustic Stimulation↗
PubMedDate not supplied

Relation between formant frequencies and optimal octaves in vowel perception.

The purpose of this study was to investigate the relation between the traditional concept of formant frequencies and the controversial concept of optimal octaves in the perception of the vowels/i, a, u/. The vowels (produced by a male speaker of General American English) were filtered through eight bandwidths (80-160, 160-315, 315-630, 630-1,250, 1,250-2,500, 2,500-5,000, 5,000-10,000, and 10,000-20,000 Hz) and presented to two groups of subjects. One group performed similarity ratings on pairs of filtered and nonfiltered stimuli; the other identified the individual filtered and nonfiltered vowels. The optimal bandwidths derived from the data of the two groups were compared to the formant frequencies of our speaker, to those reported in the literature, and to the optimal octaves published earlier by other authors. The results showed that there were specific bandwidths which allowed for correct perception and identification of each vowel, and that these bandwidths were compatible with both the optimal octaves and the formant frequencies reported in the literature for each vowel.

Auditory Perception↗
PubMed2002

Coding of auditory temporal and pitch information by hippocampal individual cells and cell assemblies in the rat.

This study reports how hippocampal individual cells and cell assemblies cooperate for neural coding of pitch and temporal information in memory processes for auditory stimuli. Each rat performed two tasks, one requiring discrimination of auditory pitch (high or low) and the other requiring discrimination of their duration (long or short). Some CA1 and CA3 complex-spike neurons showed task-related differential activity between the high and low tones in only the pitch-discrimination task. However, without exception, neurons which showed task-related differential activity between the long and short tones in the duration-discrimination task were always task-related neurons in the pitch-discrimination task. These results suggest that temporal information (long or short), in contrast to pitch information (high or low), cannot be coded independently by specific neurons. The results also indicate that the two different behavioral tasks cannot be fully differentiated by the task-related single neurons alone and suggest a model of cell-assembly coding of the tasks. Cross-correlation analysis among activities of simultaneously recorded multiple neurons supported the suggested cell-assembly model.Considering those results, this study concludes that dual coding by hippocampal single neurons and cell assemblies is working in memory processing of pitch and temporal information of auditory stimuli. The single neurons encode both auditory pitches and their temporal lengths and the cell assemblies encode types of tasks (contexts or situations) in which the pitch and the temporal information are processed.

Acoustic Stimulation↗
PubMed1976

Some detrimental effects of using extra stimuli to guide learning in normal and autistic children.

This study was designed to assess the effectiveness of using prompts (extra "guiding" stimuli) for teaching normal and autistic children. One group of normal children was pretrained on a color discrimination. Later, the colors were used as prompts (presented simultaneously with new training stimuli) to teach four new discriminations. Another group of normal children was trained on the same discriminations with a trial-and-error procedure (i.e., no prompting). A third group consisted of autistic children who were trained on these discriminations using the prompt procedure. Analyses of the results showed the following. (1) The trial-and-error group of normal children acquired more discriminations than the prompt group of normal children. (2) A comparison of the two prompt groups showed that the autistics failed to transfer from the prompt cue to the training cue more often than the normal children; rather, the autistics generally continued responding to the faded color cue. (3) Autistic and normal children who failed to acquire the discriminations when trained with a prompt procedure did acquire these discriminations when no prompt was used. That is, the results suggest that the presentation of an extra guiding stimulus was detrimental to the acquisition of training discriminations for all subjects, and particularly so far autistic children. Therefore, the common practice of providing extra guiding stimuli in proportion to the severity of the learning disorder may actually be harmful to the learning of new skills. Implications of these results for future research are discussed.

Acoustic Stimulation↗
PubMed2005

Enhanced contrast sensitivity in auditory cortex as cats learn to discriminate sound frequencies.

To better understand the nature and time course for learning-induced cortical reorganization, we examined frequency-specific changes in auditory cortex as cats gradually improved at a difficult sound frequency discrimination task. Three adult cats were trained to discriminate between a tone pip at a fixed target frequency (S-) and a higher deviant frequency (S+). An adaptive training schedule led to an efficient estimate of the frequency discrimination threshold (FDT), which was used to track daily performance. Each cat was also implanted with an array of microwires in auditory cortex. Tone pips with different frequency and amplitude were used to map receptive fields. Onset responses were correlated with training time and the cat's ability to discriminate frequencies. Although lifetime of the neural implants varied among cats, each provided sufficient neural recording to relate at least 3 weeks of learning to response changes in the cortex. An improved FDT was associated with a differential decrease in response strength between the S- frequency and S+ frequencies. Response to the training frequencies gradually located in a local minimum compared to adjacent frequencies (p < 0.001, Cohen's d=0.50). Cortical changes were consistent with a theory of bimodal generalization that enhances stimulus classification by reducing similarity between reinforced and nonreinforced stimuli. Such a strategy may be especially appropriate during an early stage of learning to discriminate similar sounds and differ from later strategies required for fine discrimination.

Animals↗
PubMed1979

A model of unidimensional perceptual matching.

Faster same than different judgments typically are obtained when two letters are compared. When two tones that might differ only on frequency are compared, however, same judgments typically are slower than different judgments. A uniprocessor, unidimensional model, based on Krueger's noisy-operator theory, was fitted satisfactorily to data from four published studies of tone comparison. The model predicts faster response time on different judgments because of heterogeneity of difference. Because the second tone in a pair typically may be either higher or lower in frequency than the first, there will be a greater variety of perceived difference counts on different pairs than on same pairs. As a result, a large difference count will be decisive and will lead to an immediate "different" response, because it can be produced only by a different pair, whereas a small difference count will not be so decisive because it can be produced by either a same or a different pair. Consequently, there generally will be more rechecking on same than different pairs, and thus longer RT on same pairs.

Auditory Perception↗
PubMed1998

Dissociation of visual and auditory pattern discrimination functions within the cat's temporal cortex.

In ablation-behavior experiments performed in adult cats, a double dissociation was demonstrated between ventral posterior suprasylvian cortex (vPS) and temporo-insular cortex (TI) lesions on complex visual and auditory tasks. Lesions of the vPS cortex resulted in deficits at visual pattern discrimination, but not at a difficult auditory discrimination. By contrast, TI lesions resulted in profound deficits at discriminating complex sounds, but not at discriminating visual patterns. This pattern of dissociation of deficits in cats parallels the dissociation of deficits after inferior temporal versus superior temporal lesions in monkeys and humans.

Analysis of Variance↗
PubMed2005

Identification and bisection of temporal durations and tone frequencies: common models for temporal and nontemporal stimuli.

Two experiments examined identification and bisection of tones varying in temporal duration (Experiment 1) or frequency (Experiment 2). Absolute identification of both durations and frequencies was influenced by prior stimuli and by stimulus distribution. Stimulus distribution influenced bisection for both stimulus types consistently, with more positively skewed distributions producing lower bisection points. The effect of distribution was greater when the ratio of the largest to smallest stimulus magnitude was greater. A simple mathematical model, temporal range frequency theory, was applied. It is concluded that (a) similar principles describe identification of temporal durations and other stimulus dimensions and (b) temporal bisection point shifts can be understood in terms of psychophysical principles independently developed in nontemporal domains, such as A. Parducci's (1965) range frequency theory.

Attention↗
PubMed1978

Infant recognition of mother's voice.

Each of a group of one-month-old infants was reinforced, contingent upon nonutritive sucking, with its mother's voice and the voice of a stranger. In this experiment, two conditions were applied. Under the first, the mother's speech was aimed at communicating with the infant, while, under the second, the mother's speech lacked prosodic and intonational aspects of normal speech. It was shown that infants will suck more for their mother's voices under the intonanted condition only. It was concluded that a young infant prefers its own mother's voice provided the mother speaks normally.

Discrimination, Psychological↗
PubMedDate not supplied

Aging impairs the ability to ignore irrelevant information in frequency discrimination tasks.

Age effects on the ability to ignore irrelevant auditory information were studied using frequency discrimination threshold (FDT) tasks. FDTs were determined in an unmasked condition with target tones in isolation, and in two backward-masked conditions with a nontarget masking tone presented 20 to 240 ms after the target. One masked condition included irrelevant variability in the masker frequency, but the other did not. The no-variability condition yielded more masking in older than in young adults. Masker variability induced large FDT elevations in both groups; however, the improvement in FDTs with training was large in young but only minimal in older adults.

Acoustic Stimulation↗
PubMed1979

A brain event related to the making of a sensory discrimination.

Event-related potentials associated with detected targets in a vigilance task were analyzed in two ways: (i) by sorting the potentials in terms of sequential reaction time bins of 50 milliseconds and (ii) by examining the single trial waveforms. A negative component (N2) covaried in latency with reaction time. These results support the hypothesis that N2 reflects a decision process which controls behavioral responses in sensory discrimination tasks.

Behavior↗