Cancellation model of pitch perception

A model of pitch perception is presented involving an array of delay lines and inhibitory gating neurons. In response to a periodic sound, a minimum appears in the pattern of outputs of the inhibitory neurons at a lag equal to the period of the sound. The position of this minimum is the cue to pitch. The model is similar to the autocorrelation model of pitch, multiplication being replaced by an operation similar to subtraction, and maxima by minima. The two models account for a wide class of pitch phenomena in very much the same way. The principal goal of this paper is to demonstrate this fact. Several features of the cancellation model may be to its advantage: it is closely related to the operation of harmonic cancellation that can account for segregation of concurrent harmonic stimuli, it can be generalized to explain the perception of multiple pitches, and it shows a greater degree of sensitivity to phase than autocorrelation, which may allow it to explain certain phenomena that autocorrelation cannot account for.     

Absolute and relative pitch discrimination in serial pitch perception by birds.

Four European starlings (Sturnus vulgaris) were successfully trained to discriminate a set of temporally configured 4-tone sequences that rose in pitch on a whole-tone scale from a set of otherwise identical 4-tone sequences that fell in pitch. A series of transfer tests assessed their ability to maintain the discrimination (a) when the intensity of the tones in the patterns was varied and (b) when the patterns were shortened to 1, 2, or 3 tones. The discrimination was maintained when intensity values changed, which indicated that apparent loudness was not a relevant cue for accurate performance. When sequences were shortened, overall discrimination performance diminished. Shortened sequences produced evidence for both absolute and relative pitch perception in sequence discrimination. The discrimination depended in part on the ability to "name" particular pitches in the sequences and in part on the ability to detect that a given sequence rose or fell in pitch. Results have implications for cognitive processes in serial acoustic pattern perception by animals, for a comparative study of pitch perception guided by theories encompassing absolute and relative pitch, and for research seeking the functionally significant dimensions of natural birdsong. (45 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Musical pitch perception with electrical stimulation of the cochlea

Studies were undertaken to investigate the ability of a user of the Nucleus multi-electrode cochlear implant to judge pitch in the context of musical intervals. The subject had qualified as a musical instrument tuner before he received his implant, and was able to judge the intervals between electrical sensations with neither training nor the guidance of familiar melodies. The procedures used were interval estimation, and interval production by the method of adjustment. The pitch of the electrical stimulation was controlled by varying the pulse repetition rate, the active electrode position, or two combinations of these parameters. Further studies employed sinusoidally amplitude modulated pulse trains with varying modulation frequency. The results showed that rate or modulation frequency could convey musical pitch information over a limited range (approximately two octaves). The data were directly comparable with the relationship between musical intervals and frequency for normal hearing. The pitch related to electrode place varied in accordance with the tonotopic organization of the cochlea, and also appeared to be able to support musical intervals. When both place and rate varied together, the place-related pitch was generally dominant. In all cases, the judgement of intervals tended to diverge from their acoustic counterparts as the intervals became larger.     

Mechanisms of phonological inference in speech perception.

Cross-modal priming experiments have shown that surface variations in speech are perceptually tolerated as long as they occur in phonologically viable contexts. For example, [fre[i]p] (frayp) gains access to the mental representation of freight when in the context of [fre[i]pbeara] (frayp bearer) because the change occurs in normal speech as a process of place assimilation. The locus of these effects in the perceptual system was examined. Sentences containing surface changes were created that either agreed with or violated assimilation rules. The lexical status of the assimilated word also was manipulated, contrasting lexical and nonlexical accounts. Two phoneme monitoring experiments showed strong effects of phonological viability for words, with weaker effects for nonwords. It is argued that the listener's percept of the form of speech is a product of a phonological inference process that recovers the underlying form of speech. This process can operate on both words and nonwords, although it interacts with the retrieval of lexical information. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Working memory enhances visual perception: Evidence from signal detection analysis.

We show that perceptual sensitivity to visual stimuli can be modulated by matches between the contents of working memory (WM) and stimuli in the visual field. Observers were presented with an object cue (to hold in WM or to merely attend) and subsequently had to identify a brief target presented within a colored shape. The cue could be re-presented in the display, where it surrounded either the target (on valid trials) or a distractor (on invalid trials). Perceptual identification of the target, as indexed by A′, was enhanced on valid relative to invalid trials but only when the cue was kept in WM. There was minimal effect of the cue when it was merely attended and not kept in WM. Verbal cues were as effective as visual cues at modulating perceptual identification, and the effects were independent of the effects of target saliency. Matches to the contents of WM influenced perceptual sensitivity even under conditions that minimized competition for selecting the target. WM cues were also effective when targets were less likely to fall in a repeated WM stimulus than in other stimuli in the search display. There were no effects of WM on decisional criteria, in contrast to sensitivity. The findings suggest that reentrant feedback from WM can affect early stages of perceptual processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Relative pitch perception in Japanese monkeys (Macaca fuscata).

To investigate whether monkeys perceive relative pitch, the author trained 3 Japanese monkeys (Macaca fuscata) to detect changes from rising to falling contours of 3-tone sequences. Tone sequences were presented serially with transposition, so monkeys were urged to attend to cues other than the absolute frequency of a component tone. Results from probe tests with novel sequences showed that monkeys discriminated by the relative pitch when the frequency ranges of sequences were within the training range, showing a similar tendency as birds in previous studies (e.g., S. H. Hulse, J. Cynx, & J. Humpal, 1984). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Waves of pattern formation and signal pathways

OBJECTIVE: To report a case of pill-induced esophagitis caused by oral rifampin. DATA SOURCES: English-language references identified via a MEDLINE search from January 1966 to May 1998 and a bibliographic review of pertinent articles. DATA SYNTHESIS: A large number of oral medications have been reported to cause pill-induced esophagitis. This case represents the second report attributed to rifampin. A 70-year-old white man receiving vancomycin, gentamicin, and oral rifampin for treatment of Staphylococcus epidermidis prosthetic valve endocarditis reported dysphagia immediately after swallowing a rifampin capsule on the fourth day of therapy. The following day, fiberoptic laryngoscopy and esophagoscopy demonstrated a red capsule partially embedded in the neopharynx. A day later, upper esophageal obstruction consistent with edema related to pill-induced esophagitis was identified by barium swallow. Following the procedure, the patient was placed on total parenteral nutrition and took nothing by mouth. Sixteen days after first reporting dysphagia, he was placed on a full liquid diet. Several factors may have increased the patient's risk for pill-induced esophagitis, including age, bedridden state, gastroesophageal reflux disease, simultaneous administration of several medications, and neopharyngeal stricture. CONCLUSIONS: Oral rifampin may cause esophagitis. Healthcare providers should be alert to the possibility of pill-induced esophagitis in susceptible patients. Patients with predisposing factors for the development of pill-induced esophagitis should be educated about proper swallowing of oral medications.     

The quantitative study of shape and pattern perception.

There is a need to extend the traditional psycho-physical methods to include the analysis of shapes or patterns. Heretofore studies designed to determine how form perception is influenced by various extrinsic factors have employed arbitrarily designed stimuli. This paper proposes several methods "for drawing 'random' patterns and shapes from clearly defined hypothetical populations, to which experimental results may then be generalized with measurable confidence." 27 references. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Relative pitch perception is constrained by absolute pitch in songbirds (Mimus, Molothrus, and Sturnus).

Assessed the ability of starlings (Sturnus vulgaris), cowbirds (Molothrus ater), and a mockingbird (Mimus polyglottos) to maintain a relative pitch discrimination when the absolute frequencies of a serial pattern of tones were changed. In Exp I, 7 Ss learned a relative pitch discrimination between 4-tone sequences that either ascended or descended in frequency within a 1-octave range. Results show that Ss lost the discrimination completely when the frequency range was shifted an octave above or below the initial training range. Recovery of the discrimination in the novel ranges was slow, and considerable relearning was necessary. Starling Ss, however, easily generalized the relative pitch discrimination to new frequencies within the original training range. In Exp II, 4 starlings were trained on the same relative ascending–descending discrimination in 2 noncontiguous frequency ranges. Ss lost the discrimination when transferred into a novel gap of frequencies between the original training ranges. Findings demonstrate that songbirds can learn a relational discrimination between serial pitch patterns but that their ability to generalize the discrimination is constrained markedly by the frequency range in which the sound sequences are learned initially. (46 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A motor signal and "visual" size perception

Recent models of the visual system in primates suggest that the mechanisms underlying visual perception and visuomotor control are implemented in separate functional streams in the cerebral cortex. However, a little-studied perceptual illusion demonstrates that a motor-related signal representing arm position can contribute to the visual perception of size. The illusion consists of an illusory size change in an afterimage of the hand when the hand is moved towards or away from the subject. The motor signal necessary for the illusion could be specified by feedforward and/or feedback sources (i.e. efference copy and/or proprioception/kinesthesis). We investigated the nature of this signal by measuring the illusion's magnitude when subjects moved their own arm (active condition, feedforward and feedback information available), and when arm movement was under the control of the experimenter (passive condition, feedback information available). Active and passive movements produced equivalent illusory size changes in the afterimages. However, the illusion was not obtained when an after-image of subject's hand was obtained prior to movement of the other hand from a very similar location in space. This evidence shows that proprioceptive/kinesthetic feedback was sufficient to drive the illusion and suggests that a specific three-dimensional registration of proprioceptive input and the initial afterimage is necessary for the illusion to occur.     

A developmental look at pattern symmetry in perception and memory.

A speeded sequential same–different paradigm was used to measure the pattern goodness effect at a visual encoding stage and a short-term memory stage in observers aged from 6 to 22 years. Pairs of nine-dot patterns varying in goodness were presented to subjects in three experiments. Experiment 1 used a 1-s retention interval and found larger goodness effects in short-term memory than at encoding for all observers. Furthermore, the memory effects decreased with age, whereas no age change was observed for the encoding effects. Experiment 2 generalized these findings to other retention intervals (0 and 3 s). No age differences were found in the O-s condition, whereas the 3-s condition showed large changes with age. An unexpected result indicated that an additive model of encoding and memory could not be assumed. Experiment 3 used new subjects and a mixed-trials design to replicate this finding. It is suggested that pattern goodness may affect information processing at three stages: encoding, retention, and pattern comparison. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The role of structure in infant visual pattern perception.

In Exp 1, 15 infants (aged 4 mo 2 days to 5 mo 9 days) were presented with a symmetrical (SYP) and an asymmetrical pattern (ASP), using a paired comparison preference technique. The SYPs represented vertical, horizontal, 2-fold, and 4-fold symmetry (SYM). 15 infants (aged 3 mo 29 days, to 5 mo 16 days) in Exp 2 additionally viewed patterns with 8-fold SYM, using the same procedure as Exp 1. Ss preferred patterns with multiple axes of bilateral SYM relative to ASPs. Also, vertically oriented single axis bilateral SYM was more salient than horizontally oriented SYM. The perception of structure appears to be basic to the functioning of the visual system. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mechanisms regulating Raf-1 activity in signal transduction pathways

Raf-1 is a key protein involved in the transmission of developmental and proliferative signals generated by receptor and nonreceptor tyrosine kinases. Biochemical and genetic studies have demonstrated that Raf-1 functions downstream of activated tyrosine kinases and Ras and upstream of mitogen-activated protein kinase (MAPK) and MAPK kinase (MKK or MEK) in many signaling pathways. A major objective of our laboratory has been to determine how Raf-1 becomes activated in response to signaling events. Using mammalian, baculovirus, and Xenopus systems, we have examined the roles that phosphorylation and protein-protein interactions play in regulating the biological and biochemical activity of Raf-1. Our studies have provided evidence that the activity of Raf-1 can be modulated by both Ras-dependent and Ras-independent pathways. Recently, we reported that Arg89 of Raf-1 is a residue required for the association of Raf-1 and Ras. Mutation of this residue disrupted interaction with Ras and prevented Ras-mediated, but not protein kinase C-or tyrosine kinase-mediated, enzymatic activation of Raf-1 in the baculovirus expression system. Further analysis of this mutant demonstrated that kinase-defective Raf-1 proteins interfere with the propagation of proliferative and developmental signals by binding to Ras and blocking Ras function. Our findings have also shown that phosphorylation events play a role in regulating Raf-1. We have identified sites of in vivo phosphorylation that positively and negatively alter the biological and enzymatic activity of Raf-1. In addition, we have found that some of these phosphorylation sites are involved in mediating the interaction of Raf-1 with potential activators (Fyn and Src) and with other cellular proteins (14-3-3). Results from our work suggest that Raf-1 is regulated at multiple levels by several distinct mechanisms.     

Person perception and the Type A coronary-prone behavior pattern.

Investigated the influence of the Type A behavior pattern on attribution processes using 48 male undergraduates. It was predicted that Type A Ss would be more motivated to succeed in the Prisoner's Dilemma game than would Type B's. Increased motivation to succeed was predicted to lead Type A's to exaggerate the amount of dispositional information they would believe they had inferred from observing the behavior of a future opponent, since such a belief would lead to increased confidence about predicting the target's behavior and thus increase Ss' perceived control over the outcome. Results support the predictions when the hard-driving competitiveness dimension of the Type A pattern was used as the individual difference variable. Moreover, evaluations of future opponents in the Prisoner's Dilemma game also differed as a function of the hard-driving competitive dimension. Results are discussed in terms of a person by situation interactive model of motivational influences on attribution processes and in terms of potential interpersonal effects of the cognitive behavior of Type A individuals. (41 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Auditory temporal pattern perception in 6- and 12-month-old infants.

A go/no-go conditioned head-turn paradigm was used to examine 20 6- and 20 12-mo-olds' abilities to discriminate changes in temporal grouping and their perception of absolute and relative timing information when listening to patterns of white-noise bursts. 6-mo-olds performed absolute timing discriminations both when the number of groupings of a pattern were changed and when the number of groupings remained invariant and the duration parameters of elements comprising a single group were altered. They did not, however, reliably discriminate changes in relative timing information that resulted in the number of groups remaining invariant while the number of elements comprising a group changed. 12-mo-olds readily performed both types of temporal grouping discriminations, demonstrating equally high performance for absolute and relative timing-discrimination conditions. For the absolute timing parameters tested, there was no evidence of any age-related change in the temporal resolving power of the auditory system. Ss at both ages reliably performed signal–silence duration discriminations spanning .04–.06 to .10–.15 sec. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Chemosensory and photosensory perception in purple photosynthetic bacteria utilize common signal transduction components

The chemotaxis gene cluster from the photosynthetic bacterium Rhodospirillum centenum contains five open reading frames (ORFs) that have significant sequence homology to chemotaxis genes from other bacteria. To elucidate the functions of each ORF, we have made various mutations in the gene cluster and analyzed their phenotypic defects. Deletion of the entire che operon (delta che), as well as nonpolar disruptions of cheAY, cheW, and cheR, resulted in a smooth-swimming phenotype, whereas disruption of cheB resulted in a locked tumbly phenotype. Each of these mutants was defective in chemotactic response. Interestingly, disruption of cheY resulted in a slight increase in the frequency of tumbling/reversal with no obvious defects in chemotactic response. In contrast to observations with Escherichia coli and several other bacteria, we found that all of the che mutant cells were capable of differentiating into hyperflagellated swarmer cells when plated on a solid agar surface. When viewed microscopically, the smooth-swimming che mutants exhibited active surface motility but were unable to respond to a step-down in light intensity. Both positive and negative phototactic responses were abolished in all che mutants, including the cheY mutant. These results indicate that eubacterial photosensory perception is mediated by light-generated signals that are transmitted through the chemotaxis signal transduction cascade.     

Treatment with enalapril modifies the pain perception pattern in hypertensive patients

The cardiovascular system shares numerous anatomic and functional pathways with the antinociceptive network. The aim of this study was to investigate whether angiotensin-converting enzyme (ACE) inhibitor treatment could affect hypertension-related hypalgesia. Twenty-five untreated hypertensive patients, together with a control group of 14 normotensive subjects, underwent dental pain perception evaluation by means of a pulpar test (graded increase of test current applied to healthy teeth). After the evaluation of the dental pain threshold (occurrence of pulp sensation) and tolerance (time when the subjects asked for the test to be stopped), all the subjects underwent a 24-hour ambulatory blood pressure monitoring. The hypertensive group then was treated with 20 mg/d enalapril, whereas the normotensive subjects remained without any treatment. After a time interval of 6+/-2 months, the dental pain sensitivity was retested in all the subjects, and ambulatory blood pressure was recorded during treatment in the hypertensive patients. At the first assessment, hypertensive patients showed a higher pain threshold than normotensive subjects (P<.001). On retesting of pain sensitivity in hypertensive patients, a significant decrease of both pain threshold and tolerance, leading to their normalization, was observed during treatment (P<.001 and P<.005, respectively), in the presence of reduced 24-hour and office blood pressure values. A slight, though significant, correlation was observed between variations in pain tolerance and baseline blood pressure changes occurring during treatment. During follow-up, the normotensive subjects did not show any significant pain perception or office blood pressure changes. Hypertension-related hypalgesia was confirmed. Mechanisms acting both through lowering of blood pressure and specific pharmacodynamic properties may account for the normalization of pain sensitivity observed in hypertensive patients during treatment with ACE inhibitors.