Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Pitch Discrimination”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 361 records · Page 20Linked to original sources
PubMed1991

Effects of discrete-trial and free-operant procedures on the acquisition and maintenance of successive discrimination in rats.

Rats were trained on a successive discrete-trial discrimination between two tonal stimuli to examine the effects of availability of a lever during intertrial intervals. In the discrete-trial condition, in which a lever was removed from the chamber during intertrial intervals, 10-s trials were initiated by the presentation of both discriminative stimulus and lever. In the free-operant condition, in which a lever was present during both trials and intertrial intervals, 10-s trials were initiated only by the presentation of a discriminative stimulus. Experiment 1 employed 50-s intertrial intervals and demonstrated that discriminative performances were acquired faster and maintained better in the free-operant conditions than in the discrete-trial conditions. Experiment 2 employed 5-s intertrial intervals and showed that poor discriminative performances in the discrete-trial conditions were improved. These results indicate that the presentation of a lever to start a trial can overshadow or mask the control by a discriminative stimulus and thereby obstruct the acquisition and maintenance of discriminative performances. Furthermore, the overshadowing or masking effects are strengthened as a function of the duration of intertrial intervals.

Animals↗
PubMed1987

Organizational processes in infants' perception of auditory patterns.

Infants 9-11 months of age were tested for their discrimination of changes in the melodic contour (direction of successive pitch changes) of brief melodies in the context of discernible variations in key (different absolute frequencies, same intervals) or interval size (different absolute frequencies and frequency ratios, same contour). Infants detected contour changes in both variable contexts, suggesting that they categorize sequences of sounds on the basis of global, relational properties such as melodic contour. Implications of such processing strategies for infants' perception of running speech are considered.

Attention↗
PubMedDate not supplied

[Participation of the amygdala in the formation of heterogeneous conditioned reflexes].

Characteristics were studied in the same dogs of the formation of conditioned reflexes to signals reinforced by biologically different stimuli--food, acid and current and of differentiations to them, after amygdala ablation. Amygdalectomy leads to the disturbance of the conditioning process, independently of the biological significance of the reinforcement. However, the deepest and the most prolonged disturbances occur in the system of alimentary behaviour and in elaboration of more complicated instrumental defensive reflexes in which current avoidance requires not only lifting of the paw but also retaining at a definite height for a certain time. Amygdala ablation considerably impedes the process of differentiation of positive and inhibitory stimuli leading to a disturbance of correct evaluation of signal significance and to inadequate behavioural reactions.

Amygdala↗
PubMed2003

Selective loss of timbre perception for keyboard and percussion instruments following a right temporal lesion.

We report the case of a 65-year-old man WDK, who experienced selective loss of timbre perception for keyboard and percussion instruments following a right temporal stroke comprising the anterior superior and medial gyrus and parts of the insular region. Formerly an avid listener to music, the sound of an orchestra appeared to be "flat" to him. WDK and a matched control subject underwent a detailed neuropsychological test battery covering basic auditory function (audiometry and just notable difference for pitch shifts), specific auditory function (recognition of environmental sounds), specific musical functions like discrimination of pitch, interval, contour, rhythm and metre, recognition of familiar melodies, emotional responsiveness, perception of timbre and auditory spectral analysis. While WDK displayed no deficits in primary auditory function, the test battery revealed a selective impairment in the perception of timbre of keyboard and percussion instruments which could be traced to a deficit in discriminating rapid changes of the spectral composition of a tone. Hence, these findings demonstrate the existence of highly specific neural networks underlying isolated aspects of timbre perception in the right anterior temporal lobe.

Acoustic Stimulation↗
PubMed2003

Can listeners hear who is singing? A comparison of three-note and six-note discrimination tasks.

Timbre is typically investigated as a perceptual attribute that differentiates a sound source at one pitch and loudness. Yet the perceptual usefulness of timbre is that it allows the listener to recognize one sound source at different pitches. This paper investigated the ability of listeners to identify which pitch in an ascending or descending sequence of three or six stimuli was sung by a different singer. For three-note sequences, the task was extremely difficult, and with rare exceptions, listeners chose the most dissimilarly pitched stimulus as coming from the oddball singer. For six-note sequences, the detection of the oddball singer was much improved in spite of the added complexity of the task. These results support the idea that timbre should be understood as a transformation that connects the different sounds of one source and that a "rich" set of sounds is necessary to discover the trajectory.

Adult↗
PubMed1989

Cortical deafness cannot account for the inability of Japanese macaques to discriminate species-specific vocalizations.

Bilateral ablation of the superior temporal gyrus in Japanese macaques results in a significant hearing loss (cortical deafness) as well as in an inability to discriminate between two types of their "coo" vocalizations. A two-part investigation was conducted to determine whether the hearing loss may itself affect the ability to discriminate vocalizations. First, four normal Japanese macaques were tested for their ability to discriminate coos which were filtered to simulate the effect of a cortical hearing loss. Second, four Japanese macaques with bilateral superior temporal gyrus lesions were tested for their ability to discriminate coos which were amplified and equalized to compensate for each animal's hearing loss. All four normal macaques were able to discriminate the filtered coos easily whereas compensating for the operated monkeys' hearing losses did not improve their performances. It appears that the inability of monkeys with bilateral superior temporal gyrus lesions to discriminate conspecific vocalizations is not simply due to the accompanying hearing loss, but is a separate auditory disorder.

Animals↗
PubMed1985

Thalamic negativity associated with the endogenous late positive component of cerebral evoked potentials (P300): recordings using discriminative aversive conditioning in humans and cats.

Electrical potentials within the thalamus associated with the endogenous late positive component (LPC or P300) of cerebral evoked potentials were investigated in humans and cats. Essentially identical discrimination tasks using classical aversive conditioning were employed for recording LPC in both species. In humans, a negative wave within the same latency range as that of LPC was noted, with dependency on stimulus-relevance, at all thalamic and mesencephalic recording sites which included the nucl. centrum medianum, nucl. parafascicularis, and periaqueductal gray. Similar negative waves were also observed over wide areas of the thalamus of cats including specific as well as non-specific thalamic nuclei. The negative waves seen in the thalamus were generally higher in amplitude than those seen in the white matter and became unclear when the electrodes penetrated the ventral border of the thalamus.

Animals↗
PubMed2004

Detection of linear temporal drift in sound sequences: empirical data and modelling principles.

Three experiments determined the perceptual threshold (JND) for detecting tempo change; i.e. linear continuous increase or decrease in inter onset interval (IOI) in sequences with 2-9 brief sounds. JND decreased as a power function of the number of intervals presented (Expt. 1). JND increased with IOI and exhibited breakpoints in this respect close to 1 and 1.4 s (Expt. 3), in agreement with previous results for serial interval production. No interaction was apparent between IOI and number of intervals (Expt. 2). None of the experiments showed any effect of direction (increasing or decreasing intervals). The results are inconsistent with several conceivable principles for perceiving tempo change, except for one in which the external intervals are compared with the intervals generated by an internal, periodic process. The plausibility of this principle is discussed in the light of recent research on sensorimotor synchronisation.

Adult↗
PubMed1998

Muscimol suppression of the dorsal cochlear nucleus impairs frequency discrimination in rats.

The cochlear nucleus is composed of three sub-nuclei: the dorsal (DCN), anteroventral (AVCN) and posteroventral cochlear nucleus (PVCN). In addition to connections between these sub-nuclei, each nucleus receives frequency specific tonotopically organised input from the cochlea. Evidence suggests that connections from the DCN to the AVCN are inhibitory and organised tonotopically but the functional significance of this pathway has yet to be elucidated. The possible role of this pathway in frequency discrimination using a T-maze behavioural paradigm and DCN suppression was examined. Five rats were trained on a two choice frequency discrimination task. Once frequency difference limens for 10-30% performance above chance were determined, rats had cannulae implanted bilaterally over the DCN. After recovery rats were tested on the behavioural task with nothing, saline and the GABA agonist muscimol injected into the DCN via the cannulae. Muscimol alone significantly reduced the rats ability to perform the task. This performance decrease was attributed to an inability to discriminate high frequency and not low frequency tones suggesting that place and not temporal coding of sound was compromised by DCN suppression. These results are consistent with the hypothesis that inhibitory drive from the DCN to AVCN may be crucial for the fine tuning of frequency information.

Acoustic Stimulation↗
PubMed2002

Altered performance of schizophrenia patients in an auditory detection and discrimination task: exploring the 'self-monitoring' model of hallucination.

It has been suggested that perceptual hallucination results from a bias in attributing a self-generated event to an external source. The 'self-monitoring' model proposes that the impairment arises from a defective corollary discharge in perceptual decisions. However, psychophysical studies in schizophrenia patients have not found consistent support for the model. We re-explored this issue by including subjects with mood disorders as patient controls and employed signals of variable intensities in an auditory detection and discrimination task. Using signal detection theory, we found decreased sensitivity in auditory detection and discrimination in schizophrenia patients, as compared to control subjects. Moreover, the psychometric functions of schizophrenics had a shallower slope than those of the controls. According to the uncertainty theory of signal detection, this suggested that schizophrenia patients monitored a smaller number of perceptual channels. On the other hand, hallucinating and non-hallucinating schizophrenia patients did not differ from each other, nor did they as a group differ from control subjects in terms of response bias. Overall, our results do not support the idea that hallucination results from an altered bias in the online processing of perceptual signals.

Adult↗
PubMed2004

Auditory discrimination training for the treatment of tinnitus.

This paper presents a series of 12 cases of chronic tinnitus patients who participated in 4 weeks of auditory discrimination training either close to or far removed from the tinnitus frequency. The training was based on the assumption that tinnitus is related to a shift of the representation of the tinnitus frequency in auditory cortex outside of the normal tonotopic map and that training close to but not removed from the tinnitus frequency should result in a reduction in the severity of the tinnitus. Tinnitus severity was measured 4 times per day during the entire treatment and other tinnitus-related variables were assessed 1 week before and 1 month posttreatment. The comparison of the training close to as compared to remote from the tinnitus frequency did not yield a statistically significant difference. However, a post hoc analysis revealed that patients who engaged in regular training as compared to those who practiced irregularly were significantly more successful in reducing tinnitus severity independent of the trained frequencies. Treatment success was best predicted by days of training and general activity levels. The data suggest that auditory discrimination training shows a dose response effect irrespective of training location and that treatment success is also related to psychological variables. For more substantial changes in multiple variables an extended training period with additional consideration of emotional variables would be necessary. In addition, controls for nonspecific training effects need to be implemented.

Acoustic Stimulation↗
PubMed1976

Stream segregation and the illusion of overlap.

When two different sounds continuously alternate at high speed, they segregate into two perceptual streams. The present article shows that this segregation produces a loss of information regarding the sequential relations of the sounds so that they seem perceptually to be overlapped in time. The segregation (and its contribution to perceived overlap) is shown to increase with the perceptual difference between the sounds. The mapping from perceptual difference to perceived overlap is not simple, however, since perceived overlap can also be affected by "perceived auditory continuity," another perceptual effect that responds differently to the perceptual difference between the two sounds.

Acoustic Stimulation↗
PubMed1984

Interaction between drug discriminative stimuli and exteroceptive, sensory signals.

Interactions between drug discriminative stimuli (based on 5.6 mg/kg and 10 mg/kg pentobarbital) and exteroceptive stimuli (visual and auditory) were studied in a T-maze. In three groups, visual stimuli (light vs. dark) were differentially paired with drug stimuli; the fourth group discriminated combinations of tonal frequencies (1 kHz or 10 kHz) and the presence or absence of pentobarbital. (10 mg/kg). In general, visual stimuli controlled choice behavior (left or right turn) to a greater extent than did the drug training stimuli, whereas the auditory stimuli exerted no apparent control over the pentobarbital stimulus in Group 4. Tests with doses higher than the training doses indicated augmented stimulus control by the drug dimension in two groups (Group 1, 10 mg/kg pentobarbital vs. saline; Group 2, 5.6 mg/kg vs. 10 mg/kg pentobarbital) but not in the third group (5.6 mg/kg pentobarbital vs. saline) in the "conflict" situation, that is, the exteroceptive conditions signaled one response whereas the drug stimulus signaled the opposite response. Discrimination training with only one of the stimulus dimensions resulted in stimulus control in the following order: 10 mg/kg vs. saline greater than 5.6 mg/kg vs. saline greater than 1 kHz vs. 10 kHz, results indicating that the auditory stimuli were of marginal significance. In conclusion, drugs can complete with exteroceptive, visual stimuli for associative strength.

Animals↗
PubMed1975

Food-reinforced inhibition of conditioned salivation in dogs.

Twelve dogs salivated to a tone that was followed by food, but not to a noise for which there was an added response dependency. The noise was followed by food if and only if they did not salivate. The addition of this response dependency vitiated the classically conditioned response to the noise. A yoked-control group of 6 dogs receiving the same sequences of stimuli and food salivated to both the tone and noise stimuli.

Acoustic Stimulation↗
PubMed1975

Olfactory discrimination, reversal learning, and stimulus control in rats.

Rats were trained to discriminate lights, tones, or odors and then given a series of discrimination reversals. Only rats trained with odors showed positive transfer on the first reversal and acquisition of a reversal set. Other experiments demonstrated that rats preferentially attend to odors when presented in compound with lights or tones; that odors exert more discriminative control than tones in tests using compound stimuli of competing sign; and that after pretraining on the positive stimulus, acquisition of an odor but not a light discrimination occurs with virtually no errors. These results demonstrate the importance of stimulus modality in the establishment of stimulus control and the need for more careful analysis of stimulus factors in cross-species comparisons of learning ability.

Animals↗