Auditory Noise Research Articles

Children do not recalibrate motor-sensory temporal order after exposure to delayed sensory feedback.

Prolonged adaptation to delayed sensory feedback to a simple motor act (such as pressing a key) causes recalibration of sensory-motor synchronization, so instantaneous feedback appears to precede the motor act that caused it (Stetson, Cui, Montague & Eagleman, 2006). We investigated whether similar recalibration occurs in school-age children. Although plasticity may be expected to be even greater in children than in adults, we found no evidence of recalibration in children aged 8-11 years. Subjects adapted to delayed feedback for 100 trials, intermittently pressing a key that caused a tone to sound after a 200 ms delay. During the test phase, subjects responded to a visual cue by pressing a key, which triggered a tone to be played at variable intervals before or after the keypress. Subjects judged whether the tone preceded or followed the keypress, yielding psychometric functions estimating the delay when they perceived the tone to be synchronous with the action. The psychometric functions also gave an estimate of the precision of the temporal order judgment. In agreement with previous studies, adaptation caused a shift in perceived synchrony in adults, so the keypress appeared to trail behind the auditory feedback, implying sensory-motor recalibration. However, school children of 8 to 11 years showed no measureable adaptation of perceived simultaneity, even after adaptation with 500 ms lags. Importantly, precision in the simultaneity task also improved with age, and this developmental trend correlated strongly with the magnitude of recalibration. This suggests that lack of recalibration of sensory-motor simultaneity after adaptation in school-age children is related to their poor precision in temporal order judgments. To test this idea we measured recalibration in adult subjects with auditory noise added to the stimuli (which hampered temporal precision). Under these conditions, recalibration was greatly reduced, with the magnitude of recalibration strongly correlating with temporal precision.

The influence of auditory-motor coupling on fractal dynamics in human gait.

Humans exhibit an innate ability to synchronize their movements to music. The field of gait rehabilitation has sought to capitalize on this phenomenon by invoking patients to walk in time to rhythmic auditory cues with a view to improving pathological gait. However, the temporal structure of the auditory cue, and hence the temporal structure of the target behavior has not been sufficiently explored. This study reveals the plasticity of auditory-motor coupling in human walking in relation to ‘complex' auditory cues. The authors demonstrate that auditory-motor coupling can be driven by different coloured auditory noise signals (e.g. white, brown), shifting the fractal temporal structure of gait dynamics towards the statistical properties of the signals used. This adaptive capability observed in whole-body movement, could potentially be harnessed for targeted neuromuscular rehabilitation in patient groups, depending on the specific treatment goal.

Electrocorticography Reveals Enhanced Visual Cortex Responses to Visual Speech

Human speech contains both auditory and visual components, processed by their respective sensory cortices. We test a simple model in which task-relevant speech information is enhanced during cortical processing. Visual speech is most important when the auditory component is uninformative. Therefore, the model predicts that visual cortex responses should be enhanced to visual-only (V) speech compared with audiovisual (AV) speech. We recorded neuronal activity as patients perceived auditory-only (A), V, and AV speech. Visual cortex showed strong increases in high-gamma band power and strong decreases in alpha-band power to V and AV speech. Consistent with the model prediction, gamma-band increases and alpha-band decreases were stronger for V speech. The model predicts that the uninformative nature of the auditory component (not simply its absence) is the critical factor, a prediction we tested in a second experiment in which visual speech was paired with auditory white noise. As predicted, visual speech with auditory noise showed enhanced visual cortex responses relative to AV speech. An examination of the anatomical locus of the effects showed that all visual areas, including primary visual cortex, showed enhanced responses. Visual cortex responses to speech are enhanced under circumstances when visual information is most important for comprehension.

Investigating the effect of respiratory bodily threat on the processing of emotional pictures

It has been demonstrated that emotions can substantially impact the perception and neural processing of breathlessness, but little is known about the reverse interaction. Here, we examined the impact of breathlessness on emotional picture processing. The continuous EEG was recorded while volunteers viewed positive/neutral/negative emotional pictures under conditions of resistive-load-induced breathlessness, auditory noise, and an unloaded baseline. Breathlessness attenuated P1 and early posterior negativity (EPN) ERP amplitudes, irrespective of picture valence. Moreover, as expected, larger amplitudes for positive and negative pictures relative to neutral pictures were found for EPN and the late positive potential (LPP) ERPs, which were not affected by breathlessness. The results suggest that breathlessness impacts on the early attention-related neural processing of picture stimuli without influencing the later cognitive processing of emotional contents.

Seeing to hear? Patterns of gaze to speaking faces in children with autism spectrum disorders.

Using eye-tracking methodology, gaze to a speaking face was compared in a group of children with autism spectrum disorders (ASD) and a group with typical development (TD). Patterns of gaze were observed under three conditions: audiovisual (AV) speech in auditory noise, visual only speech and an AV non-face, non-speech control. Children with ASD looked less to the face of the speaker and fixated less on the speakers’ mouth than TD controls. No differences in gaze were reported for the non-face, non-speech control task. Since the mouth holds much of the articulatory information available on the face, these findings suggest that children with ASD may have reduced access to critical linguistic information. This reduced access to visible articulatory information could be a contributor to the communication and language problems exhibited by children with ASD.

Supramodal processing optimizes visual perceptual learning and plasticity

Multisensory interactions are ubiquitous in cortex and it has been suggested that sensory cortices may be supramodal i.e. capable of functional selectivity irrespective of the sensory modality of inputs (Pascual-Leone and Hamilton, 2001; Renier et al., 2013; Ricciardi and Pietrini, 2011; Voss and Zatorre, 2012). Here, we asked whether learning to discriminate visual coherence could benefit from supramodal processing. To this end, three groups of participants were briefly trained to discriminate which of a red or green intermixed population of random-dot-kinematograms (RDKs) was most coherent in a visual display while being recorded with magnetoencephalography (MEG). During training, participants heard no sound (V), congruent acoustic textures (AV) or auditory noise (AVn); importantly, congruent acoustic textures shared the temporal statistics – i.e. coherence – of visual RDKs. After training, the AV group significantly outperformed participants trained in V and AVn although they were not aware of their progress. In pre- and post-training blocks, all participants were tested without sound and with the same set of RDKs. When contrasting MEG data collected in these experimental blocks, selective differences were observed in the dynamic pattern and the cortical loci responsive to visual RDKs. First and common to all three groups, vlPFC showed selectivity to the learned coherence levels whereas selectivity in visual motion area hMT+ was only seen for the AV group. Second and solely for the AV group, activity in multisensory cortices (mSTS, pSTS) correlated with post-training performances; additionally, the latencies of these effects suggested feedback from vlPFC to hMT+ possibly mediated by temporal cortices in AV and AVn groups. Altogether, we interpret our results in the context of the Reverse Hierarchy Theory of learning (Ahissar and Hochstein, 2004) in which supramodal processing optimizes visual perceptual learning by capitalizing on sensory-invariant representations — here, global coherence levels across sensory modalities.

Effects of Divided Attention and Operating Room Noise on Perception of Pulse Oximeter Pitch Changes

Background: Anesthesiology requires performing visually oriented procedures while monitoring auditory information about a patient’s vital signs. A concern in operating room environments is the amount of competing information and the effects that divided attention has on patient monitoring, such as detecting auditory changes in arterial oxygen saturation via pulse oximetry. Methods: The authors measured the impact of visual attentional load and auditory background noise on the ability of anesthesia residents to monitor the pulse oximeter auditory display in a laboratory setting. Accuracies and response times were recorded reflecting anesthesiologists’ abilities to detect changes in oxygen saturation across three levels of visual attention in quiet and with noise. Results: Results show that visual attentional load substantially affects the ability to detect changes in oxygen saturation concentrations conveyed by auditory cues signaling 99 and 98% saturation. These effects are compounded by auditory noise, up to a 17% decline in performance. These deficits are seen in the ability to accurately detect a change in oxygen saturation and in speed of response. Conclusions: Most anesthesia accidents are initiated by small errors that cascade into serious events. Lack of monitor vigilance and inattention are two of the more commonly cited factors. Reducing such errors is thus a priority for improving patient safety. Specifically, efforts to reduce distractors and decrease background noise should be considered during induction and emergence, periods of especially high risk, when anesthesiologists has to attend to many tasks and are thus susceptible to error.

Female frog auditory sensitivity, male calls, and background noise: potential influences on the evolution of a peculiar matched filter

The matched filter hypothesis proposes that the tuning of females' auditory sensitivity matches the spectral energy distribution of males' signals. Such correspondence is expected to arise over evolutionary time, as it promotes conspecific information transfer and reduces interference from other sound sources. Our main objective was to determine the correspondence between the acoustic sensitivity of female frogs of Eupsophus roseus and the spectral characteristics of advertisement vocalizations produced by conspecific males. We also aimed to determine how auditory sensitivity is related to the characteristics of background noise. We analysed data on the auditory sensitivity of E. roseus females, and recordings of conspecific male vocalizations and of the acoustic environment during the breeding period of this species. Our results indicate a concordance between the auditory sensitivity of females and call spectra that would provide an appropriate detection of these signals. In addition, this matching is large relative to the correspondence between auditory sensitivity with the spectra of the abiotic and biotic background noise, with the last component being associated with calls of the related species Eupsophus vertebralis. This may be an adaptation of receivers confronting sound interference, which improves the capability of E. roseus to communicate sexually by means of acoustic signals. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 110, 814–827.

P 49. Modulation of spontaneous and TMS-evoked alpha oscillations by top-down visual attention

Simultaneous transcranial magnetic stimulation (TMS) and electroencephalography (EEG) allows the direct assessment of cortico-thalamic responsiveness by TMS-evoked EEG potentials (TEPs). Notably, the frequency composition of TEPs corresponds to the dominant spontaneous oscillation at the respective stimulation site, e.g. ′alpha′ in the visual cortex (Rosanova et al., J Neurosci 2009). Furthermore, TEPs change dramatically with shifts in neuromodulatory levels during sleep (Massimini et al., Science 2005; Bergmann et al., J Neurosci 2012), suggesting that both are generated by the same neuronal mechanisms. Indeed, rhythmic TMS of the parieto-occipital cortex can mimic alpha band (8–12 Hz) oscillations in the EEG (Thut et al., Curr Biol 2011) as well as their known impact on perceptual performance (Romei et al., J Neurosci 2010) due to gating by inhibition (Jensen et al., TICS 2012). However, does the alpha-like TEP as response to visual cortex stimulation actually resemble spontaneous alpha oscillations or rather visual evoked potentials (VEPs)? Importantly, VEPs are amplified by visual attention (Rajagovindan and Ding, J Cog Neurosci, 2011), whereas spontaneous alpha oscillations are suppressed (Foxe et al., Neurorep 1998; Fu et al., Cog Brain Res 2001). To test the similarity between transcranially evoked and spontaneous alpha oscillations, we currently investigate whether they show comparable responses to covert shifts in attention, i.e., decrease and increase in amplitude when attending the visual and auditory modality, respectively (Foxe and Snyder, Front Psychol 2011). Here, we measure TEPs my means of simultaneously applied 61-channel EEG and neuronavigated single-pulse TMS to the visual cortex while subjects attend to either visual or auditory noise patterns in order to detect slight contrast modulations. Since auditory stimuli have been shown to evoke an alpha-like response in the visual cortex (Romei, Gross and Thut, Curr Biol 2012), we use a constant stream of auditory masking noise as well as sham TMS to control for these effects. Preliminary results suggest that the TMS-evoked alpha oscillation is in fact modulated by top-down visual attention in analogy to spontaneous alpha oscillations, suggesting that both are generated by the same underlying neural mechanisms.

Unconscious imitation as a metric for crossmodal influences: Visibility of the mouth can enhance alignment to audiovisual speech.

Human perceivers unconsciously imitate the behavioral characteristics of other humans (e.g., Iacoboni, 2009). Imitated characteristics include body postures (Condon & Ogston, 1967), facial expressions (Hale & Burgoon, 1984), and subtle acoustical characteristics of perceived speech, a phenomenon known as speech alignment (e.g. Goldinger, 1998). Recent evidence shows crossmodal influences on speech alignment (Dias & Rosenblum, 2011, in review; Miller, Sanchez, & Rosenblum, 2010). Our laboratory has shown that integrated audio and visual (lipread) information for a talker’s utterance can influence the nuances of perceivers’ articulations of that same utterance. Further, these changes in perceivers’ articulations seem more sensitive to crossmodal influences than identification responses would reveal. One question raised from these results concerns the facial information that influences alignment to auditory speech. In the current investigation, 10 female undergraduates shadowed (said out-loud) 120 audiovisual words uttered by a talker, presented in auditory noise at a level where all words were easily identifiable (+10 SNR). The shadowed tokens provided either full view of the face, or the face with the mouth area blurred out. Each participant shadowed clear and blurred tokens in block order, counterbalanced between groups. When shadowing blurred stimuli prior to clear stimuli, the degree of speech alignment is enhanced when visibility of the mouth is available, MD = .027, SE = .015, t(24) = 1.854, p <.05, r = .354. No such advantage was found when shadowing clear stimuli prior to shadowing blurred stimuli, MD = -.019, SE = .016, t(24) = -1.201, p = .241, r = .238. The results suggest alignment to auditory speech can be crossmodally enhanced by visibility of the mouth, even when words are easily identifiable. These results support the possibly that in some contexts, inadvertent imitation can provide a more sensitive measure of crossmodal influences than simple identification responses. Meeting abstract presented at VSS 2013

Quantifying temporal ventriloquism in audiovisual synchrony perception

The integration of visual and auditory inputs in the human brain works properly only if the components are perceived in close temporal proximity. In the present study, we quantified cross-modal interactions in the human brain for audiovisual stimuli with temporal asynchronies, using a paradigm from rhythm perception. In this method, participants had to align the temporal position of a target in a rhythmic sequence of four markers. In the first experiment, target and markers consisted of a visual flash or an auditory noise burst, and all four combinations of target and marker modalities were tested. In the same-modality conditions, no temporal biases and a high precision of the adjusted temporal position of the target were observed. In the different-modality conditions, we found a systematic temporal bias of 25-30 ms. In the second part of the first and in a second experiment, we tested conditions in which audiovisual markers with different stimulus onset asynchronies (SOAs) between the two components and a visual target were used to quantify temporal ventriloquism. The adjusted target positions varied by up to about 50 ms and depended in a systematic way on the SOA and its proximity to the point of subjective synchrony. These data allowed testing different quantitative models. The most satisfying model, based on work by Maij, Brenner, and Smeets (Journal of Neurophysiology 102, 490-495, 2009), linked temporal ventriloquism and the percept of synchrony and was capable of adequately describing the results from the present study, as well as those of some earlier experiments.

Cellular temperature compensation of sensory receptor neuron responses

Temperature is known to modulate ion channel kinetics and hence also action-potential generation. This poses a challenge for neural systems that need to retain their functionality also under conditions of varying temperature. Multiple strategies to counterbalance the effects of environmental temperature changes exist: mammals keep their body temperature approximately constant, while poikilothermic species need to implement temperature-compensation at the behavioral, systems, or cellular level. While mechanisms of behavioral and systems level have been identified [1], cellular mechanisms of temperature-compensation as well as their associated metabolic cost remain largely unknown. We investigated the effect of temperature on auditory processing in the grasshopper. We recorded intracellular responses of auditory receptor neurons to auditory broad-band noise stimuli at different intensities at two distinct behaviorally relevant temperatures. Interestingly, we found that changes in temperature did not have large effects on sound-intensity coding in receptor neurons. These neurons constitute the input layer of a feedforward network and hence do not receive network input. We concluded that the observed temperature robustness of receptor-neuron responses must arise from intrinsic, network unrelated effects. In general, the receptor-neuron response is shaped by two processing steps: mechanosensory transduction and spike generation. Both can contribute to temperature compensation. Either both transduction and spike generation are compensated (hypothesis I), or alternatively, their temperature dependencies can cancel each other (hypothesis II). To test hypothesis I we assumed a temperature-invariant transduction and asked, first, whether temperature-compensation could be achieved for a spike-generating mechanism with realistic temperature dependencies of the ionic conductances. The latter refers, in particular, to increases of gating kinetics by a factor of 2-4 with temperature increments of 10°C (defining a Q10 value of 2-4) as well as modest increases of peak conductances. Second, we explored whether temperature compensation, if achieved cell-intrinsically, compromises the neuronal energy budget. In other words, is temperature robustness metabolically expensive? To address these questions, we varied the temperature dependence of ionic conductances in a conductance-based neuron model. Based on the spike frequency vs. input current (f-I) relation, we estimated the ability of the model neurons to keep a robust firing rate despite changing temperature. Moreover, we computed the average energetic cost per action potential [2]. Using a database modeling approach [3], we performed a systematic sensitivity analysis for firing-rate changes and energetic cost as a function of the temperature dependence of conductance parameters (i.e. Q10 values of transition rates and peak conductances). Our analysis shows that the key parameters determining the robustness of spike generation relate to the temperature-dependence of the model's potassium conductances. In contrast, energy consumption is governed by the temperature dependence of the sodium conductance. Consequently, a neuron can achieve temperature-compensation of its firing rate without compromising the energy budget. To constrain hypothesis II, we used the experimentally observed f-I curves in an objective function and inferred the corresponding transduction process for each spike generation in our sensitivity analysis. Our results predict that thermosensitive Transient Receptor Potential (TRP) channels have a role in mechanosensory transduction at the grasshopper tympanum, and therefore motivate further experiments.

Neural Response Phase Tracks How Listeners Learn New Acoustic Representations

Humans are remarkable at rapidly learning regularities through experience from a dynamic environment. For example, long-lasting memories are formed even for auditory noise patterns after short, repeated exposure in an unsupervised manner. Although animal neurophysiological and human studies demonstrate adaptive cortical plasticity after sensory learning and memory formation, the mechanisms by which the auditory system extracts and encodes holistic patterns from random noise, which contains neither semantic labels nor prominent acoustic features to facilitate encoding, remains unknown. Here we combined magnetoencephalography (MEG) with psychophysics to address the issue. We demonstrate that the establishment of a reliable neuronal phase pattern in low-frequency (3-8 Hz) auditory cortical responses mirrors the noise memory formation process. Specifically, with repeated exposure, originally novel noise patterns are memorized, as reflected in behavior, and gradually produce robust phase responses in auditory cortex. Moreover, different memorized noises elicit distinguishable phase responses, suggesting their specificity to noise structure. The results indicate that the gradual establishment of low-frequency oscillatory phase patterns in auditory neuronal responses mediates the implicit learning process by which originally undifferentiated noises become new auditory objects.

Effects of Divided Attention and Operating Room Noise on Perception of Pulse Oximeter Pitch Changes

Anesthesiology requires performing visually oriented procedures while monitoring auditory information about a patient's vital signs. A concern in operating room environments is the amount of competing information and the effects that divided attention has on patient monitoring, such as detecting auditory changes in arterial oxygen saturation via pulse oximetry. The authors measured the impact of visual attentional load and auditory background noise on the ability of anesthesia residents to monitor the pulse oximeter auditory display in a laboratory setting. Accuracies and response times were recorded reflecting anesthesiologists' abilities to detect changes in oxygen saturation across three levels of visual attention in quiet and with noise. Results show that visual attentional load substantially affects the ability to detect changes in oxygen saturation concentrations conveyed by auditory cues signaling 99 and 98% saturation. These effects are compounded by auditory noise, up to a 17% decline in performance. These deficits are seen in the ability to accurately detect a change in oxygen saturation and in speed of response. Most anesthesia accidents are initiated by small errors that cascade into serious events. Lack of monitor vigilance and inattention are two of the more commonly cited factors. Reducing such errors is thus a priority for improving patient safety. Specifically, efforts to reduce distractors and decrease background noise should be considered during induction and emergence, periods of especially high risk, when anesthesiologists has to attend to many tasks and are thus susceptible to error.

What goes up must come down: EEG phase modulates auditory perception in both directions

What goes up must come down: EEG phase modulates auditory perception in both directions

Noise alters beta-band activity in superior temporal cortex during audiovisual speech processing

Speech recognition is improved when complementary visual information is available, especially under noisy acoustic conditions. Functional neuroimaging studies have suggested that the superior temporal sulcus (STS) plays an important role for this improvement. The spectrotemporal dynamics underlying audiovisual speech processing in the STS, and how these dynamics are affected by auditory noise, are not well understood. Using electroencephalography, we investigated how auditory noise affects audiovisual speech processing in event-related potentials (ERPs) and oscillatory activity. Spoken syllables were presented in audiovisual (AV) and auditory only (A) trials at three different auditory noise levels (no, low, and high). Responses to A stimuli were subtracted from responses to AV stimuli, separately for each noise level, and these responses were subjected to the statistical analysis. Central ERPs differed between the no noise and the two noise conditions from 130 to 150 ms and 170 to 210 ms after auditory stimulus onset. Source localization using the local autoregressive average procedure revealed an involvement of the lateral temporal lobe, encompassing the superior and middle temporal gyrus. Neuronal activity in the beta-band (16 to 32 Hz) was suppressed at central channels around 100 to 400 ms after auditory stimulus onset in the averaged AV minus A signal over the three noise levels. This suppression was smaller in the high noise compared to the no noise and low noise condition, possibly reflecting disturbed recognition or altered processing of multisensory speech stimuli. Source analysis of the beta-band effect using linear beamforming demonstrated an involvement of the STS. Our study shows that auditory noise alters audiovisual speech processing in ERPs localized to lateral temporal lobe and provides evidence that beta-band activity in the STS plays a role for audiovisual speech processing under regular and noisy acoustic conditions.

Ego depletion results in an increase in spontaneous false memories

The primary aim of the current study was to examine whether depleted cognitive resources might have ramifications for the formation of neutral and negative spontaneous false memories. To examine this, participants received neutral and negative Deese/Roediger-McDermott false memory wordlists. Also, for half of the participants, cognitive resources were depleted by use of an ego depletion manipulation (solving difficult calculations while being interfered with auditory noise). Our chief finding was that depleted cognitive resources made participants more vulnerable for the production of false memories. Our results shed light on how depleted cognitive resources affect neutral and negative correct and errant memories.

Listening to White Noise Counteracts Visual and Haptic Pseudoneglect

Neurologically intact individuals usually show a leftward bias in line bisection, a tendency known as "pseudoneglect", likely reflecting a right-hemisphere dominance in controlling the allocation of spatial attention. Studies in brain-damaged patients with left visuospatial neglect have reported that auditory stimulation may reduce the deficit, both in a spatially dependent and in a spatially independent way. Here we show for the first time that the concurrent binaural presentation of auditory white noise affects healthy individuals' performance in both visual and haptic bisection, reducing their leftward error. We suggest that this effect depends on the noise boosting alertness and restoring the hemispheric activation balance. Our data clearly show that task-irrelevant auditory noise crossmodally affects the allocation of spatial resources in both the haptic and the visual space; future research may clarify whether these effects are specific for the type of auditory stimulation.

Multisensory Enhancement in Auditory and Visual Noise in Adults

Multisensory Enhancement in Auditory and Visual Noise in Adults

Immature Multisensory Enhancement in Auditory and Visual Noise in Adolescents

Immature Multisensory Enhancement in Auditory and Visual Noise in Adolescents