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We recruited subjects who reported feeling stressed and needing a break and were seeking an opportunity to experience relaxation. Inaudible binaural beats (BB) were used to measure the ability of BB to induce relaxation. Measurements included EEG, Menlascan (cardiovascular and ANS) (Menla Technologies, Independence, Missouri), and GDV (Gas Discharge Visualization/Kirlian Photography) (Korotkov et al., 2020). Further, a Big Five Character Assessment was administered, and individual Brief Mood Introspection Scales (BMIS) were collected for each condition. Subjects experienced an improvement in brain function, microcirculation or cardiovascular score, bioenergy, and a calmer brain after adding binaural beats to brown noise or to music plus brown noise, although the Menlascan scores and Big Five character assessment results were less conclusive. BB seems to have profound effects on the physiology of subjects, and since the beats were not audible, these effects could not be attributed to the placebo effect. These results are encouraging in terms of developing musical products incorporating BB to affect human neural rhythms and corollary states of consciousness and warrant further research with more subjects and different frequencies of BB and different music tracks. [ABSTRACT FROM AUTHOR]

We recruited subjects with the focus on people who were stressed and needed a break to experience relaxation. The study used inaudible binaural beats (BB) to measure the ability of BB to induce a relaxed state. We found through measuring brain wave activity that in fact BB seem to objectively induce a state of relaxation. We were able to see this across several scores, F3/F4 Alpha Assessment and CZ Theta Beta, calculated from EEG readings, that indicated an increase in positive outlook and a relaxing brain, respectively, and scalp topography maps. Most subjects also showed an improvement in Menlascan measurements of microcirculation or cardiovascular score, although the Menlascan scores and Big Five character assessment results were less conclusive. BB seem to have profound effects on the physiology of subjects and since the beats were not audible, these effects could not be attributed to the placebo effect. These results are encouraging in terms of developing musical products incorporating BB to affect human neural rhythms and corollary states of consciousness and warrant further research with more subjects and different frequencies of BB and different music tracks. [ABSTRACT FROM AUTHOR]

We recruited subjects with the focus on people who were stressed and needed a break to experience relaxation. The study used inaudible binaural beats (BB) to measure the ability of BB to induce a relaxed state. We found through measuring brain wave activity that in fact BB seem to objectively induce a state of relaxation. We were able to see this across several scores, F3/F4 Alpha Assessment and CZ Theta Beta, calculated from EEG readings, that indicated an increase in positive outlook and a relaxing brain, respectively, and scalp topography maps. Most subjects also showed an improvement in Menlascan measurements of microcirculation or cardiovascular score, although the Menlascan scores and Big Five character assessment results were less conclusive. BB seem to have profound effects on the physiology of subjects and since the beats were not audible, these effects could not be attributed to the placebo effect. These results are encouraging in terms of developing musical products incorporating BB to affect human neural rhythms and corollary states of consciousness and warrant further research with more subjects and different frequencies of BB and different music tracks.

Dichotic pitches such as the Huggins pitch (HP) and the binaural edge pitch (BEP) are perceptual illusions whereby binaural noise that exhibits abrupt changes in interaural phase differences (IPDs) across frequency creates a tonelike pitch percept when presented to both ears, even though it does not produce a pitch when presented monaurally. At the perceptual and cortical levels, dichotic pitches behave as if an actual tone had been presented to the ears, yet investigations of neural correlates of dichotic pitch in single-unit responses at subcortical levels are lacking. We tested for cues to HP and BEP in the responses of binaural neurons in the auditory midbrain of anesthetized cats by varying the expected pitch frequency around each neuron's best frequency (BF). Neuronal firing rates showed specific features (peaks, troughs, or edges) when the pitch frequency crossed the BF, and the type of feature was consistent with a well-established model of binaural processing comprising frequency tuning, internal delays, and firing rates sensitive to interaural correlation. A Jeffress-like neural population model in which the behavior of individual neurons was governed by the cross-correlation model and the neurons were independently distributed along BF and best IPD predicted trends in human psychophysical HP detection but only when the model incorporated physiological BF and best IPD distributions. These results demonstrate the existence of a rate-place code for HP and BEP in the auditory midbrain and provide a firm physiological basis for models of dichotic pitches. NEW & NOTEWORTHY Dichotic pitches are perceptual illusions created centrally through binaural interactions that offer an opportunity to test theories of pitch and binaural hearing. Here we show that binaural neurons in auditory midbrain encode the frequency of two salient types of dichotic pitches via specific features in the pattern of firing rates along the tonotopic axis. This is the first combined single-unit and modeling study of responses of auditory neurons to stimuli evoking a dichotic pitch. [ABSTRACT FROM AUTHOR]

This study investigated claims of disrupted equilibrium when listening to the Shepard–Risset glissando (which creates an auditory illusion of perpetually ascending/descending pitch). During each trial, 23 participants stood quietly on a force plate for 90 s with their eyes either open or closed (30 s pre-sound, 30 s of sound and 30 s post-sound). Their centre of foot pressure (CoP) was continuously recorded during the trial and a verbal measure of illusory self-motion (i.e., vection) was obtained directly afterwards. As expected, vection was stronger during Shepard–Risset glissandi than during white noise or phase-scrambled auditory control stimuli. Individual differences in auditorily evoked postural sway (observed during sound) were also found to predict the strength of this vection. Importantly, the patterns of sway induced by Shepard–Risset glissandi differed significantly from those during our auditory control stimuli — but only in terms of their temporal dynamics. Since significant sound type differences were not seen in terms of sway magnitude, this stresses the importance of investigating the temporal dynamics of sound–posture interactions. [ABSTRACT FROM AUTHOR]

Background Interesting data and theories have emerged regarding auditory hallucinations (AHs) in patients with schizophrenia. The possibility that these patients may have changes in the anatomy of the auditory cortex and/or subcortical structures of the central auditory nervous system and present with deficits on audiological tests is important information to the audiology community. However, it seems clear that, in general, audiologists are not sufficiently aware of these findings. Purpose There are two main purposes of this article: (1) to educate audiologists about AHs related to schizophrenia and related issues, and (2) to encourage audiologists and hearing scientists to become involved in the evaluation and research of AHs. This fascinating disorder is one in which audiologists/hearing scientists are well suited to make a significant contribution. Research Design A review and synthesis of the literature was conducted. Relevant literature was identified through PubMed, Google Scholar, as well as independent book chapters and article searches. Keywords driving the searches were AHs, auditory illusions, verbal and musical hallucinations, schizophrenia, and central auditory disorders. Given the currency of the topic, the information collected was primarily between 1990 and 2020. Study Sample The review is organized around categorization, prevalence, models, mechanisms, anatomy, pathophysiology, and audiological correlates related to AHs. Data Collection and Analysis Searches were conducted using well-known search engines and manual searches by each author. This information on AHs was then analyzed collectively by the authors for useful background and relevance, as well as important for the field of audiology. Results Several anatomical, physiological, and functional imaging studies have shown compromise of the auditory cortex in those with schizophrenia and AHs. Potentially related to this, are studies that demonstrated sub-par performance on behavioral audiologic measures for this unique clinical population. These findings align well with the kind of hearing disorder for which audiologists are well-trained to make significant contributions. Conclusion Neurobiological and audiological evidence is accumulating on patients with schizophrenia and AH potentially rendering it as both an auditory and psychiatric disorder. Audiologists should consider expanding their horizon and playing a role in the clinical investigation of this disorder. [ABSTRACT FROM AUTHOR]

The aim of this study was to find an efficient method to determine features that characterize octave illusion data. Specifically, this study compared the efficiency of several automatic feature selection methods for automatic feature extraction of the auditory steady-state responses (ASSR) data in brain activities to distinguish auditory octave illusion and nonillusion groups by the difference in ASSR amplitudes using machine learning. We compared univariate selection, recursive feature elimination, principal component analysis, and feature importance by testifying the results of feature selection methods by using several machine learning algorithms: linear regression, random forest, and support vector machine. The univariate selection with the SVM as the classification method showed the highest accuracy result, 75%, compared to 66.6% without using feature selection. The received results will be used for future work on the explanation of the mechanism behind the octave illusion phenomenon and creating an algorithm for automatic octave illusion classification.

The award ceremony of the 10th Visual and Auditory Illusion Contest was held in the 37th annual meeting of the Japanese Psychonomic Society, Senshu University Ikuta Campus, Kawasaki, Kanagawa, Japan. The first prize was awarded to“ Helix Rotation: A New Twist on Pulfrich and Hess” produced by Arthur Shapiro, American University, Washington, D.C., USA. This illusion work was to demonstrate the Pulfrich effect beautifully. The other prize-winning illusion works were also wonderful. This article discusses the current state and prospect of this contest. [ABSTRACT FROM AUTHOR]

Highlights • EAAs are found to be 6% in the population with generalized epilepsy. • The most commonly identified EAAs are elementary auditory hallucination (60.32%). • The epileptogenic zone is in the temporal lobe of the dominance hemisphere in all patients with auditory illusion. [ABSTRACT FROM AUTHOR]

In December 1964, Roger Shepard published his article, ‘Circularity in Judgments of Relative Pitch’ in the Journal of the Acoustical Society of America. This idea lead to the development of the so-called ‘Shepard scale’ or ‘Shepard tone’. This consists is an auditory illusion that seems to be a perpetual ascending or descending glissando. Composer Jean-Claude Risset extended the illusion to rhythm, but also included the Shepard tone in one of his compositions. In popular music it was heard also in Meddle (1971), by Pink Floyd, and among academic compositions it was used in Georg Friedrich Haas’ In vain (2003). But more recently it became part of the sound design or the soundtracks of works by Christopher Nolan such as The Prestige (2006), The Dark Knight (2008), and Dunkirk (2017), and last year in Lucrecia Martel's Zama (2017). The article summarises the development of the Shepard tone and asks about the use of this illusion in the production of meaning in these films. [ABSTRACT FROM AUTHOR]

Human listeners place greater weight on the beginning of a sound compared to the middle or end when determining sound location, creating an auditory illusion known as the Franssen effect. Here, we exploited that effect to test whether human auditory cortex (AC) represents the physical vs. perceived spatial features of a sound. We used functional magnetic resonance imaging (fMRI) to measure AC responses to sounds that varied in perceived location due to interaural level differences (ILD) applied to sound onsets or to the full sound duration. Analysis of hemodynamic responses in AC revealed sensitivity to ILD in both full-cue (veridical) and onset-only (illusory) lateralized stimuli. Classification analysis revealed regional differences in the sensitivity to onset-only ILDs, where better classification was observed in posterior compared to primary AC. That is, restricting the ILD to sound onset—which alters the physical but not the perceptual nature of the spatial cue—did not eliminate cortical sensitivity to that cue. These results suggest that perceptual representations of auditory space emerge or are refined in higher-order AC regions, supporting the stable perception of auditory space in noisy or reverberant environments and forming the basis of illusions such as the Franssen effect.

Human listeners place greater weight on the beginning of a sound compared to the middle or end when determining sound location, creating an auditory illusion known as the Franssen effect. Here, we exploited that effect to test whether human auditory cortex (AC) represents the physical vs. perceived spatial features of a sound. We used functional magnetic resonance imaging (fMRI) to measure AC responses to sounds that varied in perceived location due to interaural level differences (ILD) applied to sound onsets or to the full sound duration. Analysis of hemodynamic responses in AC revealed sensitivity to ILD in both full-cue (veridical) and onset-only (illusory) lateralized stimuli. Classification analysis revealed regional differences in the sensitivity to onset-only ILDs, where better classification was observed in posterior compared to primary AC. That is, restricting the ILD to sound onset--which alters the physical but not the perceptual nature of the spatial cue--did not eliminate cortical sensitivity to that cue. These results suggest that perceptual representations of auditory space emerge or are refined in higher-order AC regions, supporting the stable perception of auditory space in noisy or reverberant environments and forming the basis of illusions such as the Franssen effect. [ABSTRACT FROM AUTHOR]

Many natural stimuli have perceptual ambiguities that can be cognitively resolved by the surrounding context. In audition, preceding context can bias the perception of speech and non-speech stimuli. Here, we develop a neuronal network model that can account for how context affects the perception of pitch change between a pair of successive complex tones. We focus especially on an ambiguous comparison -- listeners experience opposite percepts (either ascending or descending) for an ambiguous tone pair depending on the spectral location of preceding context tones.We developed a recurrent, firing-rate network model, which detects frequency-change-direction of successively played stimuli and successfully accounts for the context-dependent perception demonstrated in behavioral experiments. The model consists of two tonotopically organized, excitatory populations, Eup and Edown, that respond preferentially to ascending or descending stimuli in pitch, respectively. These preferences are generated by an inhibitory population that provides inhibition asymmetric in frequency to the two populations; context dependence arises from slow facilitation of inhibition. We show that contextual influence depends on the spectral distribution of preceding tones and the tuning width of inhibitory neurons. Further, we demonstrate, using phase-space analysis, how the facilitated inhibition from previous stimuli and the waning inhibition from the just-preceding tone shape the competition between the Eup and Edown populations. In sum, our model accounts for contextual influences on the pitch change perception of an ambiguous tone pair by introducing a novel decoding strategy based on direction-selective units. The model’s network architecture and slow facilitating inhibition emerge as predictions of neuronal mechanisms for these perceptual dynamics. Since the model structure does not depend on the specific stimuli, we show that it generalizes to other contextual effects and stimulus types.

The solitaire illusion is an illusion of numerosity proposed by Frith and Frith. In the original version, an apparent number of elements was determined by the spatial arrangement of two kinds of elements (black and white marbles). In our study, an auditory version of the solitaire illusion was demonstrated. Participants were asked to judge if they perceived more drum or piano sounds. When half of the piano tones were perceived as lower in pitch than a drum sound and the other half higher, piano tones appeared to be arranged in small units, leading to numerosity underestimation. Conversely, when all piano tones were perceived to be higher in pitch than the drum sounds, they appeared to be arranged in a single large unit, leading to numerosity overestimation. Comparable to the visual version of the solitaire illusion, the clustering seems to be determined by Gestalt principles. In our auditory version, a clear reversal of the illusion (numerosity overestimation or underestimation) was observed when piano tones appeared to be arranged in a single large cluster or in several small clusters, respectively. [ABSTRACT FROM AUTHOR]

Few studies comparing music and language processing have adequately controlled for low-level acoustical differences, making it unclear whether differences in music and language processing arise from domain-specific knowledge, acoustic characteristics, or both. We controlled acoustic characteristics by using the speech-to-song illusion, which often results in a perceptual transformation to song after several repetitions of an utterance. Participants performed a same-different pitch discrimination task for the initial repetition (heard as speech) and the final repetition (heard as song). Better detection was observed for pitch changes that violated rather than conformed to Western musical scale structure, but only when utterances transformed to song, indicating that music-specific pitch representations were activated and influenced perception. This shows that music-specific processes can be activated when an utterance is heard as song, suggesting that the high-level status of a stimulus as either language or music can be behaviorally dissociated from low-level acoustic factors. [ABSTRACT FROM AUTHOR]

According to the rhythm rule in metrical phonology, a word's stress alternates from the second syllable to the first when followed by a word with first syllable stress, a situation also known as a stress clash. For example, the secondsyllable stressed word sixTEEN will be produced as SIXteen in the phrase SIXteen CANdles. Using pseudo-words in different rhythmic contexts, we demonstrate that stress clash resolution has a strong perceptual component and can be an auditory illusion. In Experiment 1, participants were more likely to misattribute stress in a clash condition (sixTEEN heard as SIXteen in sixTEEN CANdles) than in isolation (sixTEEN) or in a non-clash condition (sixTEEN caNALS). In Experiment 2, we failed to find support for the hypothesis that nuclear stress drove these ratings. We discuss these findings in light of various theories and mechanisms for parsing spontaneous speech. [ABSTRACT FROM AUTHOR]

Abstract: Studies investigating the role of oscillatory activity in sensory perception are primarily conducted in the visual domain, while the contribution of oscillatory activity to auditory perception is heavily understudied. The objective of the present study was to investigate macroscopic (EEG) oscillatory brain response patterns that contribute to an auditory (Zwicker tone, ZT) illusion. Three different analysis approaches were chosen: 1) a parametric variation of the ZT illusion intensity via three different notch widths of the ZT-inducing noise; 2) contrasts of high-versus-low-intensity ZT illusion trials, excluding physical stimuli differences; 3) a representational similarity analysis to relate source activity patterns to loudness ratings. Depending on the analysis approach, levels of alpha to beta activity (10–20Hz) reflected illusion intensity, mainly defined by reduced power levels co-occurring with stronger percepts. Consistent across all analysis approaches, source level analysis implicated auditory cortices as main generators, providing evidence that the activity level in the alpha and beta range – at least in part – contributes to the strength of the illusory auditory percept. This study corroborates the notion that alpha to beta activity in the auditory cortex is linked to functionally similar states, as has been proposed for visual, somatosensory and motor regions. Furthermore, our study provides certain theoretical implications for pathological auditory conscious perception (tinnitus). [Copyright &y& Elsevier]

A sine tone is perceived as longer when it is preceded by a more intense noise than when presented in isolation. This is the time-stretching illusion. We conducted an experiment where the method of constant stimuli was used to examine whether a tone would also be stretched when it was followed by a noise. The duration of a tone was overestimated when it was preceded by a noise, but not when followed by a noise or when located between two consecutive noises. Moreover, the increasing of the noise intensity (from −6 to +6 dB) relative to the tone intensity resulted in larger overestimations, but only in the condition where a tone was preceded by a noise. In brief, the duration of a tone is stretched when this tone is preceded by a noise and if this tone is not followed by a noise. [ABSTRACT FROM AUTHOR]

The octave illusion was first described by Diana Deutsch in 1974; in this phenomenon, a dichotic sequence of oscillating 400 and 800 Hz sinusoidal tones evokes different illusory percepts. At the same time, the obtained percepts were found to be dependent on the subjects’ handedness. This study investigates the influence of the handedness classification method on the correlation between reported percept and handedness in the octave illusion. After presenting the stimulus, we asked a total of 174 subjects to report their percepts and complete a handedness inventory as well as a speed tapping task. According to the right shift theory of Annett (1972, 2002) and a related study by Kopiez, Galley, and Lehmann (2010), we hypothesized that the use of performance measurement to classify handedness may clarify ambiguous correlations of subjects’ handedness with some obtained illusionary percepts. The results support the general findings of Deutsch but show that stronger effects can be found if hand performance differences are used for handedness classification. A better separation between the handedness groups could be observed, especially for the complex perception patterns. [ABSTRACT FROM PUBLISHER]

Many women who pump their breast milk report that their pumps speak repeated words or phrases. Women who experience this auditory illusion interpret the pumps as commenting on the activity of pumping, taunting them, and giving advice. Often the pump insults the pumper and taunts her with her perceived inadequacies. Personal experience narratives of the talking breast pump exposes anxieties about pumping vs. breastfeeding, as well as anxieties about going back to work after giving birth. [ABSTRACT FROM AUTHOR]

Several studies have shown that maintaining in memory some attributes of speech, such as the content or pitch of an interlocutor's message, is markedly reduced in the presence of background sounds made of spectrotemporal variations. However, experimental paradigms showing this interference have only focused on one attribute of speech at a time, and thus differ from real-life situations in which several attributes have to be memorized and maintained simultaneously. It is possible that the interference is even greater in such a case and can occur for a broader range of background sounds. We developed a paradigm in which participants had to maintain the content, pitch and speaker size of auditorily presented speech information and used various auditory distractors to generate interference. We found that only distractors with spectrotemporal variations impaired the detection, which shows that similar interference mechanisms occur whether there are one or more speech attributes to maintain in memory. A high percentage of false alarms was observed with these distractors, suggesting that spectrotemporal variations not only weaken but also modify the information maintained in memory. Lastly, we found that participants were unaware of the interference. These results are similar to those observed in the visual modality. [ABSTRACT FROM AUTHOR]

Abstract: When a tone burst is divided into two parts, an onset transient and a sustained tone smoothly fading on, and these parts are delivered to two stereophonically located loudspeakers in a room, a listener gains the impression that the whole sound is coming from the loudspeaker that actually emits merely the transient. Due to this auditory illusion known as the ‘Franssen effect’ (FE), the physical and the perceived lateralizations of the sustained sound become different. A two-block mismatch negativity (MMN) paradigm was used to investigate the stage of auditory processing at which this segregation would take place. In one block, standard stimuli were 100 ms, 1 kHz tone bursts emitted by one of the loudspeakers, and deviant stimuli were their split version, with the sustained part switched to the other loudspeaker. In the other block, the roles of the two stimuli were swapped. A room acoustics software was used for generating the signals to a headphone. The responses recorded from 10 subjects displayed no MMN, although the same stimuli but without the transients evoked prominent MMNs. This indicated that the mechanism underlying this illusion modifies the neural representation of the stimulus with FE in such a way that it becomes similar to that of the stimulus without FE before reaching the input of the preattentive mechanism indexed by the MMN. Considering the possible relationship of this illusion to the precedence effect and also the relevant electrophysiological findings in the literature, we conclude that the primary auditory cortex is the most plausible site of the mechanism leading to the FE. [Copyright &y& Elsevier]

The octave illusion is a useful tool for investigation of the contribution of specialist training to auditory perception. The stimulus that induces the illusion involves two tones with a frequency ratio of 2:1, presented dichotically, and with ear of presentation reversed every 250 ms. Most listeners report hearing a single tone that alternates from high in the right ear to low in the left ear [Scientific American 233 (1975) 92–104]. The first experiment investigated the hypothesis that musical training contributes to veridical perception of an ambiguous stimulus. As hypothesized, participants with the highest level of musical training were more likely to perceive the stimulus veridically. Exploring the effects of specialist training, Experiment 2 contrasted expert pipe organists with other instrumentalists. As hypothesized, participants expert in playing pipe organ – an instrument with harmonic and spatial features similar to those of the octave illusion – were more likely to perceive the stimulus veridically. The results have implications for plasticity of the auditory system and the analytical listening that accompanies specialist, intensive training and rehearsal. [Copyright &y& Elsevier]

The aim of this study was to find an efficient method to determine features that characterize octave illusion data. Specifically, this study compared the efficiency of several automatic feature selection methods for automatic feature extraction of the auditory steady-state responses (ASSR) data in brain activities to distinguish auditory octave illusion and nonillusion groups by the difference in ASSR amplitudes using machine learning. We compared univariate selection, recursive feature elimination, principal component analysis, and feature importance by testifying the results of feature selection methods by using several machine learning algorithms: linear regression, random forest, and support vector machine. The univariate selection with the SVM as the classification method showed the highest accuracy result, 75%, compared to 66.6% without using feature selection. The received results will be used for future work on the explanation of the mechanism behind the octave illusion phenomenon and creating an algorithm for automatic octave illusion classification. [ABSTRACT FROM AUTHOR]

Abstract: Tinnitus, the phantom perception of sound with no external source, affects an estimated 10–15% of the adult population. Current treatments for this oftentimes distressing condition are of limited effectiveness. The “central gain” model proposes that tinnitus arises from an increase in the responsiveness, or gain, of neurons in central auditory pathways, triggered by damage to the auditory periphery. It has been suggested that tinnitus might be treated by compensating for the peripheral damage, thereby restoring normal levels of input to the central pathways, and hence reducing central gain. Unfortunately, when tinnitus originates with permanent damage to the auditory periphery, it may be impossible to compensate for this damage directly. However, we hypothesize that tinnitus may be treated by tricking the brain into believing that it temporarily receives normal levels of input at frequencies where peripheral damage has occurred. We identify an auditory illusion that seems capable, in principle, of achieving this objective. If effective, this approach would offer a safe, accessible, and non-invasive treatment for tinnitus. [Copyright &y& Elsevier]