Auditory Representation Research Articles

Brain basis related with the transformations from external auditory stimuli to internal auditory representations: an fMRI study

Brain basis related with the transformations from external auditory stimuli to internal auditory representations: an fMRI study

Teaching Transformations of Trigonometric Functions with Technology

Trigonometry is integral to mathematics education. The field of trigonometry plays a crucial role in the study of mathematics and its applications. Despite the importance of the subject, students struggle to understand trigonometric constructs such as angle measure. It has also been noted how students struggle to understand transformations of functions generally. Our review of the literature found few studies specifically on students’ understanding of transformations of trigonometric functions, but evidence exists showing students have difficulties with the concept. Here, a MATLAB program called TrigReps is discussed. TrigReps accepts four inputs for the algebraic representation (a)sin(bx + c) + d, and provides three additional representations as outputs. Students are presented with a graphical representation, an auditory representation, and a dynamic representation of a radius rotating around a unit circle. TrigReps has potential to be a useful tool for teaching transformations of trigonometric functions. In particular, it may be able to help students justify why combinations of horizontal transformations are counterintuitive. TrigReps is analytically sound in its design: it is interactive, dynamic, and displays Multiple External Representations (MERs) simultaneously. Initial data support its usefulness in a trigonometry classroom, but more research must be conducted to draw firm conclusions.

Auditory representation of learned sound sequences in motor regions of the macaque brain

Human speech production requires the ability to couple motor actions with their auditory consequences. Nonhuman primates might not have speech because they lack this ability. To address this question, we trained macaques to perform an auditory-motor task producing sound sequences via hand presses on a newly designed device ("monkey piano"). Catch trials were interspersed to ascertain the monkeys were listening to the sounds they produced. Functional MRI was then used to map brain activity while the animals listened attentively to the sound sequences they had learned to produce and to two control sequences, which were either completely unfamiliar or familiar through passive exposure only. All sounds activated auditory midbrain and cortex, but listening to the sequences that were learned by self-production additionally activated the putamen and the hand and arm regions of motor cortex. These results indicate that, in principle, monkeys are capable of forming internal models linking sound perception and production in motor regions of the brain, so this ability is not special to speech in humans. However, the coupling of sounds and actions in nonhuman primates (and the availability of an internal model supporting it) seems not to extend to the upper vocal tract, that is, the supralaryngeal articulators, which are key for the production of speech sounds in humans. The origin of speech may have required the evolution of a "command apparatus" similar to the control of the hand, which was crucial for the evolution of tool use.

Differential effects of the temporal and spatial distribution of audiovisual stimuli on cross-modal spatial recalibration.

Visual input constantly recalibrates auditory spatial representations. Exposure to isochronous audiovisual stimuli with a fixed spatial disparity typically results in a subsequent auditory localization bias (ventriloquism aftereffect, VAE), whereas exposure to spatially congruent audiovisual stimuli improves subsequent auditory localization (multisensory enhancement, ME). Here, we tested whether cross-modal recalibration is affected by the stimulation rate and/or the distribution of audiovisual spatial disparities during training. Auditory localization was tested before and after participants were exposed either to audiovisual stimuli with a constant spatial disparity of 13.5° (VAE) or to spatially congruent audiovisual stimulation (ME). In a between-subjects design, audiovisual stimuli were presented either at a low frequency of 2Hz, as used in previous studies of VAE and ME, or intermittently at a high frequency of 10Hz, which mimics long-term potentiation (LTP) protocols and which was found superior in eliciting unisensory perceptual learning. Compared to low-frequency stimulation, VAE was reduced after high-frequency stimulation, whereas ME occurred regardless of the stimulation protocol. In two additional groups, we manipulated the spatial distribution of audiovisual stimuli in the low-frequency condition. Stimuli were presented with varying audiovisual disparities centered around 13.5° (VAE) or 0° (ME). Both VAE and ME were equally strong compared to a fixed spatial relationship of 13.5° or 0°, respectively. Taken together, our results suggest (a) that VAE and ME represent partly dissociable forms of learning and (b) that auditory representations adjust to the overall stimulus statistics rather than to a specific audiovisual spatial relationship.

How musical experience affects tone perception efficiency by musicians of tonal and non-tonal speakers?

PurposeTo investigate if, regardless of language background (tonal or non-tonal), musicians may show stronger CP than non-musicians; To examine if native speakers of English (English or non-tonal musicians henceforth) or Mandarin Chinese (Mandarin or tonal musicians henceforth) can better accommodate multiple functions of the same acoustic cue and if musicians’ sensitivity to pitch of lexical tones comes at the cost of slower processing.MethodEnglish and Mandarin Musicians and non-musicians performed a categorical identification and a discrimination task on rising and falling continua of fundamental frequency on two vowels with 9 duration values.ResultsNon-tonal musicians exhibited significantly stronger categorical perception of pitch contour than non-tonal non-musicians. However, tonal musicians did not consistently perceive the two types of pitch directions more categorically than tonal non-musicians. Both tonal and non-tonal musicians also benefited more from increasing stimulus duration in processing pitch changes than non-musicians and they generally require less time for pitch processing. Musicians were also more sensitive to intrinsic F0 in pitch perception and differences of pitch types.ConclusionThe effect of musical training strengthens categorical perception more consistently in non-tonal speakers than tonal speakers. Overall, musicians benefit more from increased stimulus duration, due perhaps to their greater sensitivity to temporal information, thus allowing them to be better at forming a more robust auditory representation and matching sounds to internalized memory templates. Musicians also attended more to acoustic details such as intrinsic F0 and pitch types in pitch processing, and yet, overall, their categorization of pitch was not compromised by traces of these acoustic details from their auditory short-term working memory. These findings may lead to a better understanding of pitch perception deficits in special populations, particularly among individuals diagnosed with autism spectrum disorder (ASD).

Visual representations of time elicit early responses in human temporal cortex

Time perception is inherently part of human life. All human sensory modalities are always involved in the complex task of creating a temporal representation of the external world. However, when representing time, people primarily rely on auditory information. Since the auditory system prevails in many audio-visual temporal tasks, one may expect that the early recruitment of the auditory network is necessary for building a highly resolved and flexible temporal representation in the visual modality. To test this hypothesis, we asked 17 healthy participants to temporally bisect three consecutive flashes while we recorded EEG. We demonstrated that visual stimuli during temporal bisection elicit an early (50–90 ​ms) response of an extended area of the temporal cortex, likely including auditory cortex too. The same activation did not appear during an easier spatial bisection task. These findings suggest that the brain may use auditory representations to deal with complex temporal representation in the visual system.

Selective attention for affiliative and agonistic interactions of dominants and close affiliates in macaques

Monitoring conspecifics is a crucial process in social learning and a building block of social cognition. Selective attention to social stimuli results from interactions of subject and stimulus characteristics with dominance rank often emerging as an important predictor. We extend previous research by providing as stimuli naturally occurring affiliative interactions between group members instead of pictorial or auditory representations of conflicts, and by extending to the affiliative relationship, i.e. social bond, between subject and stimulus instead of just their dominance relations. Our observational data on adult female rhesus macaques support the prediction that subjects pay more attention to affiliative interactions of others than to solitary controls. Exceedingly more attention was paid to conflicts unfolding in the group which can have more prompt and direct consequences than others’ friendly interactions. The valence of the stimulus (affiliative vs. agonistic) affected biases towards individuals dominant over the subject, but not the ubiquitous bias towards close affiliates of the subject. Keeping track of the whereabouts and interactions of key social partners has been proposed as a prerequisite for behavioral coordination among bonded partners. In groups of socially very active monkeys, social attention is gated by both social dominance and social bonding.

The effect of science writing heuristic approach with multiple representation in improving students’critical thinking skills

This study aims at investigating the effect of the integration of multiple auditory representation into heuristic approach on students’ critical thinking skills. A quasi-experimental method with Pretest-Posttest Control Group design which involved in 24 participants in the experimental and control classes was applied to answer the research problem. An essay test was used to collect the data, while the paired sample T test was carried out to evaluate the impact of the implemented approach on students’ thinking skills. Significant improvement of critical thinking skills was observed for students who have applied a heuristic approach with multiple representative hearing than those students who have experienced a heuristic approach without multiple representations. The large category of effect size (1.1), suggesting that the learning process in the experimental group was more effective compared to those Learning in the control class. The current results show that the fusion of multiple auditory representation into heuristic approach provide an alternative learning approach for enhancing students’ critical thinking skills.

Mapping the human middle longitudinal fasciculus through a focused anatomo-imaging study: shifting the paradigm of its segmentation and connectivity pattern.

Τhe middle longitudinal fasciculus (MdLF) was initially identified in humans as a discrete subcortical pathway connecting the superior temporal gyrus (STG) to the angular gyrus (AG). Further anatomo-imaging studies, however, proposed more sophisticated but conflicting connectivity patterns and have created a vague perception on its functional anatomy. Our aim was, therefore, to investigate the ambiguous structural architecture of this tract through focused cadaveric dissections augmented by a tailored DTI protocol in healthy participants from the Human Connectome dataset. Three segments and connectivity patterns were consistently recorded: the MdLF-I, connecting the dorsolateral Temporal Pole (TP) and STG to the Superior Parietal Lobule/Precuneus, through the Heschl's gyrus; the MdLF-II, connecting the dorsolateral TP and the STG with the Parieto-occipital area through the posterior transverse gyri and the MdLF-III connecting the most anterior part of the TP to the posterior border of the occipital lobe through the AG. The lack of an established termination pattern to the AG and the fact that no significant leftward asymmetry is disclosed tend to shift the paradigm away from language function. Conversely, the theory of "where" and "what" auditory pathways, the essential relationship of the MdLF with the auditory cortex and the functional role of the cortical areas implicated in its connectivity tend to shift the paradigm towards auditory function. Allegedly, the MdLF-I and MdLF-II segments could underpin the perception of auditory representations; whereas, the MdLF-III could potentially subserve the integration of auditory and visual information.

Orienting Attention to Auditory and Visual Short-term Memory: The Roles of Age, Hearing Loss, and Cognitive Status

ABSTRACTBackground/Study Context: Attention can be reflectively oriented to a visual or auditory representation in short-term memory, but it is not clear how aging and hearing acuity affects reflective attention. The purpose of the present study was to examine whether performance in auditory and visual reflective attention tasks varies as a function of participants’ age and hearing status.Methods: Young (19 to 33 years) and older adults with normal or mild to moderate hearing loss (62–90 years) completed a delayed match-to-sample task in which participants were first presented with a memory array of four different digits to hold in memory. Two digits were presented visually (left and right hemifield), and two were presented aurally (left and right ears simultaneously). During the retention interval, participants were presented with a cue (dubbed retro-cue), which could be either uninformative or indicated to the participants to retrospectively orient their attention to either auditory short-term memory (ASTM) or visual short-term memory (VSTM). The cue was followed by another delay, after which a single item was presented (i.e., test probe) for comparison (match or no match) with the items held in ASTM and/or VSTM.Results: Overall, informative retro-cue yielded faster response time than uninformative retro-cue. The retro-cue benefit in response time was comparable for auditory and visual-orienting retro-cue and similar in young and older adults. Regression analyses showed that only the auditory-orienting retro-cue benefit was predicted by hearing status rather than age per se.Conclusion: Both younger and older adults can benefit from visual and auditory-orienting retro-cues, but the auditory-orienting retro-cue benefit decreases with poorer hearing acuity. This finding highlights changes in cognitive processes that come with age even in those with just mild-to-moderate hearing loss, and suggest that older adults’ performance in working memory tasks is sensitive to low level auditory scene analysis (i.e., concurrent sound segregation).

Distinct Mechanisms of Imagery Differentially Influence Speech Perception.

Neural representation can be induced without external stimulation, such as in mental imagery. Our previous study found that imagined speaking and imagined hearing modulated perceptual neural responses in opposite directions, suggesting motor-to-sensory transformation and memory retrieval as two separate routes that induce auditory representation (Tian and Poeppel, 2013). We hypothesized that the precision of representation induced from different types of speech imagery led to different modulation effects. Specifically, we predicted that the one-to-one mapping between motor and sensory domains established during speech production would evoke a more precise auditory representation in imagined speaking than retrieving the same sounds from memory in imagined hearing. To test this hypothesis, we built the function of representational precision as the modulation of connection strength in a neural network model. The model fitted the magnetoencephalography (MEG) imagery repetition effects, and the best-fitting parameters showed sharper tuning after imagined speaking than imagined hearing, consistent with the representational precision hypothesis. Moreover, this model predicted that different types of speech imagery would affect perception differently. In an imagery-adaptation experiment, the categorization of /ba/-/da/ continuum from male and female human participants showed more positive shifts towards the preceding imagined syllable after imagined speaking than imagined hearing. These consistent simulation and behavioral results support our hypothesis that distinct mechanisms of speech imagery construct auditory representation with varying degrees of precision and differentially influence auditory perception. This study provides a mechanistic connection between neural-level activity and psychophysics that reveals the neural computation of mental imagery.

Intention-based Piano Pedagogy

This research focuses on the guidance of students of piano methodology ("piano pedagogy") in acquiring didactic skills. More specifically, it aims to support them in understanding and applying research-based educational principles in their internship lessons. Recent scientific research on motor control and motor skill learning offers opportunities for evaluating current practices in piano pedagogy and coming up with innovative teaching approaches. Based on an extensive review of research results, I have formulated educational principles for achieving pianistic quality. I argue that mental auditory representations of intended musical outcomes ("musical intentions") iniate and steer musical motor control processes. Furthermore, I have summarized several research-supported teaching strategies that promote motor skill learning and presented examples of their practical application in piano pedagogy. I have applied several interventions aimed at enhancing conveyance of these educational principles to students of piano methodology. In the first place, I have created extensive study materials (booklets, videos, slide presentations) that both explain and show practical applications of these principles in piano pedagogy. Furthermore, I have introduced peer-to-peer learning: students observe and evaluate their own and each other's internship lessons. Results of this research show that further improvement of the methodology course is required in order to achieve its goals. Both the study material and the peer-learning opportunities have shown to be valuable additions. However, students still exhibit a lack of creativity in finding relevant teaching strategies within their internship lessons. I have formulated several additional interventions for further improvement.

Older adults sacrifice response speed to preserve multisensory integration performance

Aging has been shown to impact multisensory perception, but the underlying computational mechanisms are unclear. For effective interactions with the environment, observers should integrate signals that share a common source, weighted by their reliabilities, and segregate those from separate sources. Observers are thought to accumulate evidence about the world's causal structure over time until a decisional threshold is reached. Combining psychophysics and Bayesian modeling, we investigated how aging affects audiovisual perception of spatial signals. Older and younger adults were comparable in their final localization and common-source judgment responses under both speeded and unspeeded conditions, but were disproportionately slower for audiovisually incongruent trials. Bayesian modeling showed that aging did not affect the ability to arbitrate between integration and segregation under either unspeeded or speeded conditions. However, modeling the within-trial dynamics of evidence accumulation under speeded conditions revealed that older observers accumulate noisier auditory representations for longer, set higher decisional thresholds, and have impaired motor speed. Older observers preserve audiovisual localization performance, despite noisier sensory representations, by sacrificing response speed.

Hemisphere-specific properties of the ventriloquism aftereffect.

Visual calibration of auditory space requires re-alignment of representations differing in (1) format (auditory hemispheric channels vs visual maps) and (2) reference frames (head-centered vs eye-centered). Here, a ventriloquism paradigm from Kopčo, Lin, Shinn-Cunningham, and Groh [J. Neurosci. 29, 13809-13814 (2009)] was used to examine these processes in humans for ventriloquism induced within one spatial hemifield. Results show that (1) the auditory representation can be adapted even by aligned audio-visual stimuli, and (2) the spatial reference frame is primarily head-centered, with a weak eye-centered modulation. These results support the view that the ventriloquism aftereffect is driven by multiple spatially non-uniform, hemisphere-specific processes.

Neural evidence accounting for interindividual variability of the McGurk illusion

The McGurk illusion is experienced to various degrees among the general population. Previous studies have implicated the left superior temporal sulcus (STS) and auditory cortex (AC) as regions associated with this interindividual variability. We sought to further investigate the neurophysiology underlying this variability using a variant of the McGurk illusion design. Electroencephalography (EEG) was recorded while human subjects were presented with videos of a speaker uttering the consonant-vowels (CVs) /ba/ and /fa/, which were mixed and matched with audio of /ba/ and /fa/ to produce congruent and incongruent conditions. Subjects were also presented with unimodal stimuli of silent videos and audios of the CVs. They responded to whether they heard (or saw in the silent condition) /ba/ or /fa/. An illusion during the incongruent conditions was deemed successful when individuals heard the syllable conveyed by mouth movements. We hypothesized that individuals who experience the illusion more strongly should exhibit more robust desynchronization of alpha (7–12 Hz) at fronto-central and temporal sites, emphasizing more engagement of neural generators at the AC and STS. We found, however, that compared to weaker illusion perceivers, stronger illusion perceivers exhibited greater alpha synchronization at fronto-central and posterior temporal sites, which is consistent with inhibition of auditory representations. These findings suggest that stronger McGurk illusion perceivers possess more robust cross-modal sensory gating mechanisms whereby phonetic representations not conveyed by the visual system are inhibited, and in turn reinforcing perception of the visually targeted phonemes.

Human action sounds elicit sensorimotor activation early in life

In human adults the auditory representation of others’ actions is capable to activate specific areas of the motor and premotor cortices. Here, we examined the early origins of the neural processing of action sounds to investigate whether and how infants rely on auditory information to understand their close social environment. Sensorimotor activity, as indexed by μ rhythm suppression, was measured using electroencephalography in 14-month-old infants who listened to hand- and foot-produced action sounds (i.e., footsteps and clapping) and to mechanical sounds (i.e., blender). Footstep sounds elicited activation at midline electrodes over the foot area (Cz), and not in correspondence of lateralized clusters over the hand areas (C3 and C4). Greater activation in response to clapping compared to blender and footstep sounds was recorded at electrodes in the left central cluster, over the hand sensorimotor cortex (i.e., C3), but extended to some extent over the midline electrode cluster. Furthermore, our results underscore the role of natural locomotor experience in shaping sensorimotor activation, since infants who gained more walking experience exhibited stronger sensorimotor activation for footstep sounds over left central electrodes. Taken together, current results provide the first evidence that action sounds produced by another person are capable to elicit sensorimotor activation during infancy.

Top-down or bottom up: decreased stimulus salience increases responses to predictable stimuli of auditory thalamic neurons.

Temporal imprecision leads to deficits in the comprehension of signals in cluttered acoustic environments, and the elderly are shown to use cognitive resources to disambiguate these signals. To mimic ageing in young rats, we delivered sound signals that are temporally degraded, which led to temporally imprecise neural codes. Instead of adaptation to repeated stimuli, with degraded signals, there was a relative increase in firing rates, similar to that seen in aged rats. We interpret this increase with repetition as a repair mechanism for strengthening the internal representations of degraded signals by the higher-order structures. To better understand speech in challenging environments, older adults increasingly use top-down cognitive and contextual resources. The medial geniculate body (MGB) integrates ascending inputs with descending predictions to dynamically gate auditory representations based on salience and context. A previous MGB single-unit study found an increased preference for predictable sinusoidal amplitude modulated (SAM) stimuli in aged rats relative to young rats. The results suggested that the age-degraded/jittered up-stream acoustic code may engender an increased preference for predictable/repeating acoustic signals, possibly reflecting increased use of top-down resources. In the present study, we recorded from units in young-adult MGB, comparing responses to standard SAM with those evoked by less salient SAM (degraded) stimuli. We hypothesized that degrading the SAM stimulus would simulate the degraded ascending acoustic code seen in the elderly, increasing the preference for predictable stimuli. Single units were recorded from clusters of advanceable tetrodes implanted above the MGB of young-adult awake rats. Less salient SAM significantly increased the preference for predictable stimuli, especially at higher modulation frequencies. Rather than adaptation, higher modulation frequencies elicited increased numbers of spikes with each successive trial/repeat of the less salient SAM. These findings are consistent with previous findings obtained in aged rats suggesting that less salient acoustic signals engage the additional use of top-down resources, as reflected by an increased preference for repeating stimuli that enhance the representation of complex environmental/communication sounds.

Limiting relationships through sousveillance video based digital advocacy: multi-modal analysis of The Nervous CPS Worker

ABSTRACT Digital media technology and Internet-based/social media sharing are shifting the contexts and processes of social work, including the relationships emerging in practice. The Nervous CPS Worker, a digital video shared via YouTube, provides a concrete practice-based example of the use of social media self-advocacy by professional foster parents. This case-study demonstrates the fragmented and shifting power-relations brought to bear within contemporary social work. Multi-modal analysis facilitates the development of a layered qualitative understanding of this video, shaped by the researcher’s inter-textual relationship with the material. Supplemental online texts are applied to the Nervous CPS Worker and relevant scholarship, including discipline specific knowledge, reveals the layered and convergent meaning making processes present in this video through the use of auditory communication, visual representations and genre. Analysis demonstrates how contemporary social work contexts, such as neoliberalism, and standardisation are implicated in practice and how identity and context compete for recognition and space within the home visit depicted in this video.

The fidelity of visual and auditory memory.

Recent studies show that recognition memory for pictures is consistently better than recognition memory for sounds. The purpose of this experiment was to compare the fidelity of auditory and visual memory to better understand the reported differences in the two memory systems. Participants received a study phase with pictures/sounds, followed by a same-day memory test or a delayed recognition memory test. During the memory test, participants were presented with pictures/sounds that were old (presented during study), novel foils not presented during study, or exemplar foils that were variants of objects presented during study. Participants were instructed to classify each picture/sound as "old" or "new" by pressing a corresponding key. The same-day memory task revealed fundamental differences in visual and auditory memory: auditory representations are coarse and gist-based, while visual representations are highly detailed. However, auditory and visual memory performance was similar after a delay of 2 and 7 days and both types of memory representations were more coarse and gist-based. The results make an important contribution to our understanding of how the world is represented in auditory and visual memory.

Echo-Imaging Exploits an Environmental High-Pass Filter to Access Spatial Information with a Non-Spatial Sensor

SummaryEcho-imaging evolved as the main remote sense under lightless conditions. It is most precise in the third dimension (depth) rather than in the visually dominating dimensions of azimuth and elevation. We asked how the auditory system accesses spatial information in the dimensions of azimuth and elevation with a sensory apparatus that is fundamentally different from vision. We quantified echo-acoustic parameters of surface-wave patterns with impulse-response recordings and quantified bats' perceptual sensitivity to such patterns with formal psychophysics. We demonstrate that the spectro-temporal auditory representation of a wave pattern implicitly encodes its spatial frequency. We further show that bats are much more sensitive to wave patterns of high spatial frequencies than of low spatial frequencies. We conclude that echo-imaging accesses spatial information by exploiting an inherent environmental high-pass filter for spatial frequency. The functional similarities yet mechanistic differences between visual and auditory system signify convergent evolution of spatial-information processing.