White Noise Bursts Research Articles

Electrophysiological Indicators of the Age-Related Deterioration in the Sensitivity to Auditory Duration Deviance

The present study investigates age-related changes in duration discrimination in millisecond time domain. We tested young (N = 20, mean age = 24.5, SD = 2.97) and elderly (N = 20, mean age = 65.2, SD = 2.94) subjects using the mismatch negativity (MMN) paradigm. White-noise bursts of two different durations (50 and 10 ms) were presented in two oddball blocks. In one block (Increment Condition), the repetitive sequence of 10 ms standards was interspersed by occasional 50 ms deviants. In the Decrement Condition, the roles of the two stimuli were reversed. We analyzed the P1-N1 complex, MMN and P3a and found the effect of age for all these components. Moreover, the impact of stimulus presentation condition (increment/decrement) was observed for MMN and P3a. Our results confirmed the previous evidence for deteriorated duration discrimination in elderly people. Additionally, we found that this effect may be influenced by procedural factors.

Pavlovian conditioned diminution of the unconditioned SCR using unpleasant stimuli as the unconditioned stimulus

In this study, we investigated the possibility of obtaining conditioned diminution of the unconditioned skin conductance response (SCR) in humans using as unconditioned stimulus (US) the simultaneous presentation of an unpleasant picture and a sound. Although initial reactivity to the stimuli was similar in the experimental and control groups, after the acquisition phase, conditioned response (CR) and unconditioned response (UR) diminution were both observed. These results reveal the possibility of obtaining UR diminution by substituting the traditional aversive USs (bursts of white noise and electric shocks) with stimuli whose aversiveness derives from their semantic content more than from their intensity.

An exploratory analysis of the relations between the rate of physiological habituation, the acquired capability for suicide, and acute risk factors for suicide

Purpose – The interpersonal theory of suicide proposes that an individual must acquire the capability for suicide to carry out a near-lethal or lethal suicide attempt. This capability develops via habituation in response to painful and provocative life events. Some individuals might be more vulnerable to developing the capability for suicide because they habituate more quickly to stimuli. The purpose of this paper is to examine the relations between the rate of physiological habituation and acquired capability, proxies for acquired capability, and acute risk factors for suicide. Design/methodology/approach – Depressed, suicidal individuals completed self-report assessments and a startle reflex task assessing the rate or speed of physiological habituation in response to repeated bursts of white noise. Findings – Slower habituation was associated with hopelessness and negative stressors. The rate of habituation was not associated with acquired capability. Originality/value – The current study informs the understanding of how physiological habituation is related to suicide risk factors.

Child sex and respiratory sinus arrhythmia reactivity as moderators of the relation between internalizing symptoms and aggression.

Previous studies have examined sex differences in physiological responding, including respiratory sinus arrhythmia (RSA) reactivity in response to changing stimulus conditions involving situation specific or gender related cues, in children and adolescents. The present study examined whether RSA reactivity moderates the relation between aggression and internalizing symptoms and whether there are sex differences in this effect. Participants were 82 adolescents (M age=12.1years; 44 girls) from the general middle-school population. Peer nominations assessed aggression and internalizing symptoms, and RSA reactivity (defined as change in RSA from baseline to task) was recorded while participants anticipated and responded to an 85dB signaled white-noise burst. For girls, internalizing symptoms were associated with aggression only if girls showed low RSA reactivity from baseline to task; there was no effect for boys. This association was absent when girls showed high RSA reactivity. Thus, child sex appears to influence not only levels of physiological responding but also relations of physiological responding to comorbidity of adjustment problems.

Sound can suppress visual perception.

In a single modality, the percept of an input (e.g., voices of neighbors) is often suppressed by another (e.g., the sound of a car horn nearby) due to close interactions of neural responses to these inputs. Recent studies have also suggested that close interactions of neural responses could occur even across sensory modalities, especially for audio-visual interactions. However, direct behavioral evidence regarding the audio-visual perceptual suppression effect has not been reported in a study with humans. Here, we investigated whether sound could have a suppressive effect on visual perception. We found that white noise bursts presented through headphones degraded visual orientation discrimination performance. This auditory suppression effect on visual perception frequently occurred when these inputs were presented in a spatially and temporally consistent manner. These results indicate that the perceptual suppression effect could occur across auditory and visual modalities based on close and direct neural interactions among those sensory inputs.

Expression of freezing and fear-potentiated startle during sustained fear in mice.

Fear-potentiated acoustic startle paradigms have been used to investigate phasic and sustained components of conditioned fear in rats and humans. This study describes a novel training protocol to assess phasic and sustained fear in freely behaving C57BL/6J mice, using freezing and/or fear-potentiated startle as measures of fear, thereby, if needed, allowing in vivo application of various techniques, such as optogenetics, electrophysiology and pharmacological intervention, in freely behaving animals. An auditory Pavlovian fear conditioning paradigm, with pseudo-randomized conditioned-unconditioned stimulus presentations at various durations, is combined with repetitive brief auditory white noise burst presentations during fear memory retrieval 24 h after fear conditioning. Major findings are that (1) a motion sensitive platform built on mechano-electrical transducers enables measurement of startle responses in freely behaving mice, (2) absence or presence of startle stimuli during retrieval as well as unpredictability of a given threat determine phasic and sustained fear response profiles and (3) both freezing and startle responses indicate phasic and sustained components of behavioral fear, with sustained freezing reflecting unpredictability of conditioned stimulus (CS)/unconditioned stimulus (US) pairings. This paradigm and available genetically modified mouse lines will pave the way for investigation of the molecular and neural mechanisms relating to the transition from phasic to sustained fear.

The role of the sound of objects in object identification: evidence from picture naming.

In the present work we were concerned with the role of sound representations in object recognition. In order to address this issue we made use of a picture naming task in which target pictures might be accompanied by a white-noise burst. White-noise was thought to interfere with the representation of the sound possibly associated with the depicted object. We reasoned that if such a representation is critical for the recognition of objects strongly associated with certain sounds, white-noise interference should affect the naming of pictures representing objects with typical sounds leaving the naming of object without typical sounds unaffected. The results were congruent with the predictions and consistent with a view of the semantic representations of objects as collection of related representations, modal in nature, and mandatorily accessed.

Using the threat probability task to assess anxiety and fear during uncertain and certain threat.

Fear of certain threat and anxiety about uncertain threat are distinct emotions with unique behavioral, cognitive-attentional, and neuroanatomical components. Both anxiety and fear can be studied in the laboratory by measuring the potentiation of the startle reflex. The startle reflex is a defensive reflex that is potentiated when an organism is threatened and the need for defense is high. The startle reflex is assessed via electromyography (EMG) in the orbicularis oculi muscle elicited by brief, intense, bursts of acoustic white noise (i.e., "startle probes"). Startle potentiation is calculated as the increase in startle response magnitude during presentation of sets of visual threat cues that signal delivery of mild electric shock relative to sets of matched cues that signal the absence of shock (no-threat cues). In the Threat Probability Task, fear is measured via startle potentiation to high probability (100% cue-contingent shock; certain) threat cues whereas anxiety is measured via startle potentiation to low probability (20% cue-contingent shock; uncertain) threat cues. Measurement of startle potentiation during the Threat Probability Task provides an objective and easily implemented alternative to assessment of negative affect via self-report or other methods (e.g., neuroimaging) that may be inappropriate or impractical for some researchers. Startle potentiation has been studied rigorously in both animals (e.g., rodents, non-human primates) and humans which facilitates animal-to-human translational research. Startle potentiation during certain and uncertain threat provides an objective measure of negative affective and distinct emotional states (fear, anxiety) to use in research on psychopathology, substance use/abuse and broadly in affective science. As such, it has been used extensively by clinical scientists interested in psychopathology etiology and by affective scientists interested in individual differences in emotion.

Subjective crossmodal correspondence and audiovisual integration

Research on multisensory integration often makes use of stochastic (race) models to distinguish a response performance enhancement in Reaction Times (RTs) due to multisensory integration from an enhancement due to the probability summation. Only when performance on a multisensory task supersedes that of the race-model it is attributed to multisensory integration. An important factor affecting multisensory integration is the unity assumption, i.e. the degree to which an observer infers that two sensory inputs are of the same source or event. Apart from the obvious spatial and temporal correspondence, other, often more subjective, similarity estimates might play a role as well. Here we investigate how subjective crossmodal correspondence influences multisensory stimulation. Observers first matched the loudness of a 100ms white noise burst to the brightness of a 0.86째 light disc (6.25 cd/m2) presented for 100ms on a darker (4.95 cd/m2) background, using a staircase procedure. In a subsequent speeded detection experiment, the observers indicated as fast and accurately as possible whether an audiovisual, auditory only or visual only target was located to the right or left from fixation. The subjectively matched loudness as well as +5dB and -5 dB loudness values were used as auditory stimuli. Auditory detection was generally faster than visual detection and audio-visual detection was generally fastest. However, only when the subjectively matched loudness was used as auditory stimulus did audio-visual detection supersede the predictions made by the racemodel. This result demonstrates the importance of subjective correspondence in multisensory integration, and may explain earlier results that found a surprising lack of integration. Meeting abstract presented at VSS 2014

The role of the superior temporal lobe in auditory false perceptions: A transcranial direct current stimulation study

Neuroimaging has shown that a network of cortical areas, which includes the superior temporal gyrus, is active during auditory verbal hallucinations (AVHs). In the present study, healthy, non-hallucinating participants (N=30) completed an auditory signal detection task, in which participants were required to detect a voice in short bursts of white noise, with the variable of interest being the rate of false auditory verbal perceptions. This paradigm was coupled with transcranial direct current stimulation, a noninvasive brain stimulation technique, to test the involvement of the left posterior superior temporal gyrus in the creation of auditory false perceptions. The results showed that increasing the levels of excitability in this region led to a higher rate of ‘false alarm’ responses than when levels of excitability were decreased, with false alarm responses under a sham stimulation condition lying at a mid-point between anodal and cathodal stimulation conditions. There were also corresponding changes in signal detection parameters. These results are discussed in terms of prominent cognitive neuroscientific theories of AVHs, and potential future directions for research are outlined.

Continuous carryover of temporal context dissociates response bias from perceptual influence for duration.

Recent experimental evidence suggests that the perception of temporal intervals is influenced by the temporal context in which they are presented. A longstanding example is the time-order-error, wherein the perception of two intervals relative to one another is influenced by the order in which they are presented. Here, we test whether the perception of temporal intervals in an absolute judgment task is influenced by the preceding temporal context. Human subjects participated in a temporal bisection task with no anchor durations (partition method). Intervals were demarcated by a Gaussian blob (visual condition) or burst of white noise (auditory condition) that persisted for one of seven logarithmically spaced sub-second intervals. Crucially, the order in which stimuli were presented was first-order counterbalanced, allowing us to measure the carryover effect of every successive combination of intervals. The results demonstrated a number of distinct findings. First, the perception of each interval was biased by the prior response, such that each interval was judged similarly to the preceding trial. Second, the perception of each interval was also influenced by the prior interval, such that perceived duration shifted away from the preceding interval. Additionally, the effect of decision bias was larger for visual intervals, whereas auditory intervals engendered greater perceptual carryover. We quantified these effects by designing a biologically-inspired computational model that measures noisy representations of time against an adaptive memory prior while simultaneously accounting for uncertainty, consistent with a Bayesian heuristic. We found that our model could account for all of the effects observed in human data. Additionally, our model could only accommodate both carryover effects when uncertainty and memory were calculated separately, suggesting separate neural representations for each. These findings demonstrate that time is susceptible to similar carryover effects as other basic stimulus attributes, and that the brain rapidly adapts to temporal context.

Habituation in acoustic startle reflex: Individual differences in personality

This study analyzed the relationship of individual differences in personality with habituation in the acoustic startle response (ASR). Data from nine trials in ASR to white noise bursts and a personality questionnaire based on the alternative big five personality approach were modelled with a latent growth curve (LCM) including intercept and slope habituation growth factors. There was a negative correlation between the intercept and slope, indicating that individuals with higher initial ASR levels had also a more pronounced and faster decrease in the ASR. Contrary to expectations, Extraversion and Sensation Seeking did not relate with habituation in ASR. Neuroticism and Aggressiveness related asymmetrically with the habituation rate in ASR. Higher levels of Neuroticism were related with faster habituation, whereas higher levels of Aggressiveness were related with slower habituation. Further studies with the LCM should be undertaken to clarify in a greater extent the association of personality with habituation in ASR.

Does brain ability to synchronize with 40 Hz auditory stimulation change with age?

Auditory steady-state responses (ASSRs) are widely applied to test brain ability to follow external stimulation and this appeared to be a promising method in neuropsychiatric disorders. Nevertheless, there is no established conclusion on the way aging affects phase-locking measures of ASSRs in healthy subjects. We aimed to identify the effects of aging on phaselocking measures of 40 Hz ASSR. The effect of aging was tested in a sample of 46 healthy male subjects (20-58 years old) during eyes open condition. Stimuli were 500 ms trains, consisting of 20 identical clicks (1.5 ms burst of white noise) delivered binaurally. Time-frequency analysis of the data was performed and phase-locking index, evoked amplitude and total intensity measures were extracted and decomposed by non-negative multi-way factorization. As shown by curve-fitting analyses, phase-locking index and evoked amplitudes were diminishing with age in the linear manner. This was also proven by ANOVA testing when sample was divided into age groups. No effect of age on the total intensity was found. The complexity of the factors modulating the 40 Hz ASSR is not entirely solved; nevertheless, the current results suggest that the ability to synchronize to high frequency external stimulation diminishes with age. This should be taken into account, particularly when ASSRs are used in clinical practice, comparing patients and healthy subjects.

Neuronal interaural level difference response shifts are level-dependent in the rat auditory cortex

How does the brain accomplish sound localization with invariance to total sound level? Sensitivity to interaural level differences (ILDs) is first computed at the lateral superior olive (LSO) and is observed at multiple levels of the auditory pathway, including the central nucleus of inferior colliculus (ICC) and auditory cortex. In LSO, this ILD sensitivity is level-dependent, such that ILD response functions shift toward the ipsilateral (excitatory) ear with increasing sound level. Thus early in the processing pathway changes in firing rate could indicate changes in sound location, sound level, or both. In ICC, while ILD responses can shift toward either ear in individual neurons, there is no net ILD response shift at the population level. In behavioral studies of human sound localization acuity, ILD sensitivity is invariant to increasing sound levels. Level-invariant sound localization would suggest transformation in level sensitivity between LSO and perception of sound sources. Whether this transformation is completed at the level of the ICC or continued at higher levels remains unclear. It also remains unknown whether perceptual sound localization is level-invariant in rats, as it is in humans. We asked whether ILD sensitivity is level-invariant in rat auditory cortex. We performed single-unit and whole cell recordings in rat auditory cortex under ketamine anesthesia and measured responses to white noise bursts presented through sealed earphones at a range of ILDs. Surprisingly, we found that with increasing sound levels ILD responses shifted toward the ipsilateral ear (which is typically inhibitory), regardless of whether cells preferred ipsilateral, contralateral, or binaural stimuli. Voltage-clamp recordings suggest that synaptic inhibition does not contribute substantially to this transformation in level sensitivity. We conclude that the level invariance of ILD sensitivity seen in behavioral studies is not present in rat auditory cortex.

Are Poor Sleepers Afraid of the Dark? A Preliminary Investigation

No studies have investigated whether those with poor sleep are aware of being uncomfortable in the dark via subjective inquiry, and no study has evaluated whether poor sleepers have increased fear in the dark using objective indices (e.g., a validated startle paradigm). Good and poor sleepers (N = 108) completed questionnaires about their level of discomfort with the dark and were evaluated for an increased startle reflex by measuring eyeblink latency via electrooculogram in response to unexpected noise in the dark and the light. Participants listened to bursts of unexpected white noise, while in counterbalanced light/dark conditions. Relative to good sleepers, more poor sleepers reported increased discomfort in the dark. There was a significant lighting × time × sleeper status interaction for eyeblink latency. Relative to the first trial in the dark, eyeblink latency in good sleepers increased in the second dark exposure; suggesting habituation in the dark. Eyeblink latency in poor sleepers did not decrease. Thus, poor sleepers reported being uncomfortable in the dark and they remained more easily startled in the dark over the course of the study. It is unclear if the dark may predispose people to sleep problems, or if sleep problems sensitize poor sleepers to fear darkness.

Schizophrenia-like disruptions of sensory gating by serotonin receptor stimulation in rats: Effect of MDMA, DOI and 8-OH-DPAT

Schizophrenia pathophysiology is associated with alterations in several neurotransmitter systems, particularly dopamine, glutamate and serotonin (5-HT). Schizophrenia patients also have disruptions in sensory gating, a brain information filtering mechanism in response to repeated sensory stimuli. Dopamine and glutamate have been implicated in sensory gating; however, little is known about the contribution of serotonin. We therefore investigated the effects of several psychoactive compounds that alter serotonergic neuronal activity on event-related potentials (ERP) to paired auditory pulses. Male Sprague–Dawley rats were implanted with cortical surface electrodes to measure ERPs to 150 presentations of two 85dB bursts of white noise, 500ms apart (S1 and S2). Saline-treated animals suppressed the response to S2 to less than 50% of S1. In contrast, treatment with the serotonin releaser, MDMA (ecstasy; 2.0mg/kg), the 5-HT2A/2C receptor agonist, DOI (0.5mg/kg), or the 5-HT1A/7 receptor agonist, 8-OH-DPAT (0.5mg/kg), caused an increase in S2/S1 ratios. Analysis of waveform components suggested that the S2/S1 ratio disruption by MDMA was due to subtle effects on the ERPs to S1 and S2; DOI caused the disruption primarily by reducing the ERP to S1; 8-OH-DPAT-induced disruptions were due to an increase in the ERP to S2. These results show that 5-HT receptor stimulation alters S2/S1 ERP ratios in rats. These results may help to elucidate the sensory gating deficits observed in schizophrenia patients.

Methylmercury Exposure and Acoustic Startle Response in Adolescents: An Exploratory Study

Background The acoustic startle response (ASR) is a reflex mediated by well-described neural processes. The ASR is modified under different behavioral conditions (e.g. during attention tasks). This can be impaired in behavioral disorders, such as attention deficit disorder. Although extensively studied in animal models and some human clinical conditions, few studies have explored the use of the ASR to assess neurological effects of toxicants, and none in adolescents. Aims To describe the relationship between basic ASR amplitude, sociodemographic characteristics typically used in neurodevelopmental studies, and concurrent methylmercury (MeHg) exposure in a cohort of adolescents. Methods We report on recordings from 232 adolescents aged 8-17 years from the Early Life Exposure in Mexico to Environmental Toxicants (ELEMENT) study. The responses to 12 acoustic startle probes (50ms white noise bursts at ~100dB) per subject were recorded as electromyographic (EMG) activity of the eyeblink muscle. Multivariable linear regression was used to evaluate the association between concurrent MeHg exposure and demographic variables and the amplitude of the EMG activity in response to the acoustic probes (the ASR). Results Participants had a mean (SD) ASR amplitude of 1.67?V (2.09). The ASR showed expected habituation. Subject's age, maternal age at birth, socioeconomic status, mother's education, parent marital status, and smoking during pregnancy were not associated with log-transformed ASR amplitude. Sex of the child was associated with ASR amplitude: boys showed a 1.55?V (95% CI: 1.18, 2.03) smaller response than girls. Concurrent mean blood Hg concentration was 2.06 (2.22) ?g/L and was not associated with ASR magnitude. Conclusions Sex was strongly associated with ASR magnitude and will have to be carefully considered in future analyses. While concurrent blood Hg was not associated with ASR in the current analyses, we are continuing to increase our sample size, explore other mercury biomarkers, exposure windows, age ranges, and related neurological measures.

Startle reactivity in the long-term after severe accidental injury: Preliminary data

An exaggerated startle response is one of the core hyperarousal symptoms of posttraumatic stress disorder (PTSD). Heightened startle eye-blink magnitude and reduced habituation of this response in PTSD patients have been reported in several studies. However, it is unclear whether this is an enduring characteristic of individuals vulnerable for PTSD or to which degree trauma-exposed individuals who do not develop PTSD also show exaggerated startle. Thirteen accident survivors with remitted PTSD, 12 trauma controls, and 16 non-trauma controls were examined. Four measures of startle reactivity were analyzed in response to 15 bursts of white noise (95dB, 50ms): eye-blink magnitude, eye-blink onset latency, skin conductance response, and heart rate response. The eye-blink reflex was measured over the left musculus orbicularis oculi. Reactivity and habituation were analyzed using linear mixed models. Remitted PTSD subjects did not differ from non-trauma controls regarding any of the startle reactivity or habituation measures. Unexpectedly, trauma controls showed larger eye-blink magnitude than non-trauma controls. These results suggest that the exaggerated startle response disappears after remission from PTSD. Further, they suggest that psychologically resilient trauma survivors might show a PTSD-like pattern of exaggerated physiological startle even many years after a traumatic event.

Cichlids respond to conspecific sounds but females exhibit no phonotaxis without the presence of live males

AbstractMany fish species are able to produce sounds, which are often associated with courtship. In an earlier study, we showed for the Lake Victoria cichlid Pundamilia nyererei that females prefer to associate with a male with sound over a male without sound. As a follow‐up to this earlier finding, we here investigated whether playback of conspecific sounds is sufficient to attract females in the absence of a conspecific male. However, we did not find a phonotactic response for conspecific sounds in the absence of live males, using the same playback procedure as in our previous study. An additional playback test showed that both males and females discriminated between conspecific sounds and bursts of white noise. This suggests that the sounds may be recognised but that they seem only effective as attractant in the presence of visual and/or olfactory cues. These findings underline the multimodal complexity of fish communication and courtship and call for a more integrated study of the different modalities in future studies.

Deciding where to look based on visual, auditory, and semantic information

Neurons in the dorsal frontal and parietal cortex are thought to transform incoming visual signals into the spatial goals of saccades, a process known as target selection. Here, we used functional magnetic resonance imaging (fMRI) to test how target selection may generalize beyond visual transformations when auditory and semantic information is used for selection. We compared activity in the frontal and parietal cortex when subjects made visually, aurally, and semantically guided saccades to one of four differently colored dots. Selection was based on a visual cue (i.e., one of the dots blinked), an auditory cue (i.e., a white noise burst was emitted at one of the dots' location), or a semantic cue (i.e., the color of one of the dots was spoken). Although neural responses in frontal and parietal cortex were robust, they were non-specific with regard to the type of information used for target selection. Decoders, however, trained on the patterns of activity in the intraparietal sulcus could classify both the type of cue used for target selection and the direction of the saccade. Therefore, we find evidence that the posterior parietal cortex is involved in transforming multimodal inputs into general spatial representations that can be used to guide saccades.