Relationship between Toxoplasma gondii seropositivity and acoustic startle response in an inner-city population.

PubMed

Massa, Nick M; Duncan, Erica; Jovanovic, Tanja; Kerley, Kimberly; Weng, Lei; Gensler, Lauren; Lee, Samuel S; Norrholm, Seth; Powers, Abigail; Almli, Lynn M; Gillespie, Charles F; Ressler, Kerry; Pearce, Bradley D

2017-03-01

Toxoplasma gondii (TOXO) is a neuroinvasive protozoan parasite that induces the formation of persistent cysts in mammalian brains. It infects approximately 1.1million people in the United States annually. Latent TOXO infection is implicated in the etiology of psychiatric disorders, especially schizophrenia (SCZ), and has been correlated with modestly impaired cognition. The acoustic startle response (ASR) is a reflex seen in all mammals. It is mediated by a simple subcortical circuit, and provides an indicator of neural function. We previously reported the association of TOXO with slowed acoustic startle latency, an index of neural processing speed, in a sample of schizophrenia and healthy control subjects. The alterations in neurobiology with TOXO latent infection may not be specific to schizophrenia. Therefore we examined TOXO in relation to acoustic startle in an urban, predominately African American, population with mixed psychiatric diagnoses, and healthy controls. Physiological and diagnostic data along with blood samples were collected from 364 outpatients treated at an inner-city hospital. TOXO status was determined with an ELISA assay for TOXO-specific IgG. A discrete titer was calculated based on standard cut-points as an indicator of seropositivity, and the TOXO-specific IgG concentration served as serointensity. A series of linear regression models were used to assess the association of TOXO seropositivity and serointensity with ASR magnitude and latency in models adjusting for demographics and psychiatric diagnoses (PTSD, major depression, schizophrenia, psychosis, substance abuse). ASR magnitude was 11.5% higher in TOXO seropositive subjects compared to seronegative individuals (p=0.01). This effect was more pronounced in models with TOXO serointensity that adjusted for sociodemographic covariates (F=7.41, p=0.0068; F=10.05, p=0.0017), and remained significant when psychiatric diagnoses were stepped into the models. TOXO showed no association with

Effects of Nicotine and Nicotinic Antagonists on the Acoustic Startle Response and on Pre-Pulse Inhibition in Rats

DTIC Science & Technology

1996-06-07

the auditory nerve, the ventral cochlear nucleus , nuclei of the lateral lemniscus, nucleus reticularis pontis caudalis, spinal neuron, and lower... nucleus , nuclei of the lateral lemniscus, nucleus reticularis pontis caudalis, hippocampus, and striatum (Davis, et al., 1982; Swerdlow, et aI, 1992...Davis, M. (1985) Cocaine effects on acoustic startle and startle elicited electrically from cochlear nucleus . P§ychQpharmacology, 87, 396-399 James

Exercise is associated with reduction in the anxiogenic effect of mCPP on acoustic startle.

PubMed

Fox, James H; Hammack, Sayamwong E; Falls, William A

2008-08-01

Voluntary exercise has been associated with reduced anxiety across several animal models. Manipulation of central 5-HT can alter anxiety-like behaviors and administration of the 5-HT agonist metachlorophenylpiperazine (mCPP) increases anxiety in rodents and humans. To examine whether the anxiolytic effect of exercise is associated with an alteration in 5-HT systems, we examined the anxiogenic effect of mCPP in exercising and nonexercising mice. C57BL/6J mice were given 2 weeks of free access to either a functioning or nonfunctioning running wheel. Mice were then tested for acoustic startle following systemic injection of either 0, 0.1, 0.3, or 1 mg/kg of mCPP. Consistent with its anxiogenic properties, mCPP produced a dose-dependent increase in acoustic startle in nonexercising mice. However, this anxiogenic effect was blunted in exercising mice. These findings suggest that exercise may help to reduce anxiety by altering 5-HT systems, perhaps by down-regulating postsynaptic 5HT 2B/2C receptors.

Direct and indirect nigrofugal projections to the nucleus reticularis pontis caudalis mediate in the motor execution of the acoustic startle reflex.

PubMed

Hormigo, Sebastian; López, Dolores E; Cardoso, Antonio; Zapata, Gladys; Sepúlveda, Jacqueline; Castellano, Orlando

2018-07-01

The acoustic startle reflex (ASR) is a short and intense defensive reaction in response to a loud and unexpected acoustic stimulus. In the rat, a primary startle pathway encompasses three serially connected central structures: the cochlear root neurons, the giant neurons of the nucleus reticularis pontis caudalis (PnC), and the spinal motoneurons. As a sensorimotor interface, the PnC has a central role in the ASR circuitry, especially the integration of different sensory stimuli and brain states into initiation of motor responses. Since the basal ganglia circuits control movement and action selection, we hypothesize that their output via the substantia nigra (SN) may interplay with the ASR primary circuit by providing inputs to PnC. Moreover, the pedunculopontine tegmental nucleus (PPTg) has been proposed as a functional and neural extension of the SN, so it is another goal of this study to describe possible anatomical connections from the PPTg to PnC. Here, we made 6-OHDA neurotoxic lesions of the SN pars compacta (SNc) and submitted the rats to a custom-built ASR measurement session to assess amplitude and latency of motor responses. We found that following lesion of the SNc, ASR amplitude decreased and latency increased compared to those values from the sham-surgery and control groups. The number of dopamine neurons remaining in the SNc after lesion was also estimated using a stereological approach, and it correlated with our behavioral results. Moreover, we employed neural tract-tracing techniques to highlight direct projections from the SN to PnC, and indirect projections through the PPTg. Finally, we also measured levels of excitatory amino acid neurotransmitters in the PnC following lesion of the SN, and found that they change following an ipsi/contralateral pattern. Taken together, our results identify nigrofugal efferents onto the primary ASR circuit that may modulate motor responses.

EFFECTS OF TWO PYRETHROID INSECTICIDES ON MOTOR ACTIVITY AND THE ACOUSTIC STARTLE RESPONSE IN THE RAT

EPA Science Inventory

To better characterize the behavioral toxicity of pyrethroid insecticides, comparisons were made of the effects of cismethrin and deltamethrin exposure on motor activity and the acoustic startle response in male Long-Evans rats. Acute dose-effect, acute time course, and 30-day re...

ONTOGENY OF THE ACOUSTIC STARTLE RESPONSE AND SENSITIZATION TO BACKGROUND NOISE IN THE RAT (JOURNAL VERSION)

EPA Science Inventory

The purpose of the study was to characterize the ontogeny of the acoustic startle response (ASR), and response sensitization to background noise, in preweanling rats. With constant low-level (45 dB) background noise, response latency decreased steadily with age, whereas, both res...

Effects of brain-derived and glial cell line-derived neurotrophic factors on startle response and disrupted prepulse inhibition in mice of DBA/2J inbred strain.

PubMed

Naumenko, Vladimir S; Bazovkina, Daria V; Morozova, Maryana V; Popova, Nina K

2013-08-29

Prepulse inhibition (PPI), the reduction in acoustic startle reflex when it is preceded by weak prepulse stimuli, is a measure of critical to normal brain functioning sensorimotor gating. PPI deficit was shown in a variety of psychiatric disorders including schizophrenia, and in DBA/2J mouse strain. In the current study, we examined the effects of brain-derived (BDNF) and glial cell line-derived (GDNF) neurotrophic factors on acoustic startle response and PPI in DBA/2J mice. It was found that BDNF (300 ng, i.c.v.) significantly increased amplitude of startle response and restored disrupted PPI in 7 days after acute administration. GDNF (800 ng, i.c.v.) did not produce significant alteration neither in amplitude of startle response nor in PPI in DBA/2J mice. The reversal effect of BDNF on PPI deficit was unusually long-lasting: significant increase in PPI was found 1.5 months after single acute BDNF administration. Long-term ameliorative effect BDNF on disrupted PPI suggested the implication of epigenetic mechanism in BDNF action on neurogenesis. BDNF rather than GDNF could be a perspective drug for the treatment of sensorimotor gating impairments. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Acoustic startle response in rats predicts inter-individual variation in fear extinction.

PubMed

Russo, Amanda S; Parsons, Ryan G

2017-03-01

Although a large portion of the population is exposed to a traumatic event at some point, only a small percentage of the population develops post-traumatic stress disorder (PTSD), suggesting the presence of predisposing factors. Abnormal acoustic startle response (ASR) has been shown to be associated with PTSD, implicating it as a potential predictor of the development of PTSD-like behavior. Since poor extinction and retention of extinction learning are characteristic of PTSD patients, it is of interest to determine if abnormal ASR is predictive of development of such deficits. To determine whether baseline ASR has utility in predicting the development of PTSD-like behavior, the relationship between baseline ASR and freezing behavior following Pavlovian fear conditioning was examined in a group of adult, male Sprague-Dawley rats. Baseline acoustic startle response (ASR) was assessed preceding exposure to a Pavlovian fear conditioning paradigm where freezing behavior was measured during fear conditioning, extinction training, and extinction testing. Although there was no relationship between baseline ASR and fear memory following conditioning, rats with low baseline ASR had significantly lower magnitude of retention of the extinction memory than rats with high baseline ASR. The results suggest that baseline ASR has value as a predictive index of the development of a PTSD-like phenotype. Copyright © 2017 Elsevier Inc. All rights reserved.

Prefrontal oxygenation and the acoustic startle eyeblink response during exercise: A test of the dual-mode model.

PubMed

Tempest, Gavin D; Parfitt, Gaynor

2017-07-01

The interplay between the prefrontal cortex and amygdala is proposed to explain the regulation of affective responses (pleasure/displeasure) during exercise as outlined in the dual-mode model. However, due to methodological limitations the dual-mode model has not been fully tested. In this study, prefrontal oxygenation (using near-infrared spectroscopy) and amygdala activity (reflected by eyeblink amplitude using acoustic startle methodology) were recorded during exercise standardized to metabolic processes: 80% of ventilatory threshold (below VT), at the VT, and at the respiratory compensation point (RCP). Self-reported tolerance of the intensity of exercise was assessed prior to, and affective responses recorded during exercise. The results revealed that, as the intensity of exercise became more challenging (from below VT to RCP), prefrontal oxygenation was larger and eyeblink amplitude and affective responses were reduced. Below VT and at VT, larger prefrontal oxygenation was associated with larger eyeblink amplitude. At the RCP, prefrontal oxygenation was greater in the left than right hemisphere, and eyeblink amplitude explained significant variance in affective responses (with prefrontal oxygenation) and self-reported tolerance. These findings highlight the role of the prefrontal cortex and potentially the amygdala in the regulation of affective (particularly negative) responses during exercise at physiologically challenging intensities (above VT). In addition, a psychophysiological basis of self-reported tolerance is indicated. This study provides some support of the dual-mode model and insight into the neural basis of affective responses during exercise. © 2017 Society for Psychophysiological Research.

Deficient prepulse inhibition of acoustic startle in Hooded-Wistar rats compared with Sprague-Dawley rats.

PubMed

van den Buuse, Maarten

2003-04-01

1. Prepulse inhibition of acoustic startle has been suggested as a model of sensorimotor gating and central sensory information processing. Prepulse inhibition is impaired in patients with schizophrenia and responses can be restored by antipsychotic drug treatment. In the present study, startle and prepulse inhibition of startle were compared in different rat strains. 2. Sprague-Dawley rats showed robust inhibition of startle responses by increasing intensities of prepulse delivered just before the startle stimulus. In contrast, at both 4 and 10 weeks of age, rats of the Hooded-Wistar line had markedly reduced prepulse inhibition, although startle responses were not different. 3. Treatment with the dopamine receptor agonist apomorphine (0.1 mg/kg) or the N-methyl-d-aspartate (NMDA) receptor antagonist MK-801 (0.1 mg/kg) caused disruption of prepulse inhibition in Sprague-Dawley rats. In Hooded-Wistar rats, apomorphine further reduced the already low level of prepulse inhibition, but MK-801 treatment had no significant effect. This suggests that the impaired prepulse inhibition in Hooded-Wistar rats could be caused by changes in glutamatergic activity and/or NMDA receptors in these rats. 4. In photocell cages, spontaneous exploratory activity and inner zone activity were significantly lower in Hooded-Wistar rats than in Sprague-Dawley rats. Similarly, on the elevated plus-maze, Hooded-Wistar rats showed a lower propensity to visit the open arms. In contrast, amphetamine (0.5 mg/kg)-induced locomotor hyperactivity, an animal model of psychosis, was enhanced in Hooded-Wistar rats. 5. These data suggest that the Hooded-Wistar line could be a useful genetic animal model to study the interaction of glutamatergic and dopaminergic mechanisms in anxiety and schizophrenia.

Suppressed acoustic startle response in traumatic brain injury masks post-traumatic stress disorder hyper-responsivity.

PubMed

Liska, Grant M; Lee, Jea-Young; Xu, Kaya; Sanberg, Paul R; Borlongan, Cesario V

2018-05-21

An exaggerated acoustic startle reflex (ASR) is a clinical indicator of anxiety disorders, such as post-traumatic stress disorder (PTSD). Given the prevalence of PTSD following traumatic brain injury (TBI), we studied the effects of TBI on ASR. Adult Sprague Dawley rats exposed to moderate controlled cortical impact injury model of TBI displayed suppression of ASR intensity and sensitivity. As patients with PTSD have been shown to display hyperactive startle responses, the present discrepant observation of TBI-induced suppression of ASR has clinical implications, in that the reduced, instead of elevated, startle response in patients with comorbid TBI/PTSD could be owing to a masking effect of TBI.This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal. http://creativecommons.org/licenses/by-nc-nd/4.0/.

Atypical antipsychotic clozapine reversed deficit on prepulse inhibition of the acoustic startle reflex produced by microinjection of DOI into the inferior colliculus in rats.

PubMed

de Oliveira, Rodolpho Pereira; Nagaishi, Karen Yuriko; Barbosa Silva, Regina Cláudia

2017-05-15

Dysfunctions of the serotonergic system have been suggested to be important in the neurobiology of schizophrenia. Patients with schizophrenia exhibit deficits in an operational measure of sensorimotor gating: prepulse inhibition (PPI) of startle. PPI is the normal reduction in the startle response caused by a low intensity non-startling stimulus (prepulse) which is presented shortly before the startle stimulus (pulse). The hallucinogen 2,5-dimethoxy-4-iodoamphetamine (DOI), a 5-hydroxytryptamine(HT) 2 receptor agonist disrupted PPI in rats. The inferior colliculus (IC) is a critical nucleus of the auditory pathway mediating acoustic PPI. The activation of the IC by the acoustic prepulse reduces startle magnitude. The present study investigated the role of serotonergic transmission in the IC on the expression of acoustic PPI. For that we investigated whether 5-HT2A receptor activation or blockade would affect this response. Unilateral microinjection of DOI (10μg/0.3μl) into the IC disrupted PPI, while microinjection of the 5-HT2A receptor antagonist ritanserin (4μg/0.3μl), into this structure did not alter PPI. We also examined the ability of the atypical antipsychotic clozapine (5.0mg/kg; I.P.) to reverse the disruption of PPI produced by unilateral microinjections of DOI into the IC of rats. Pretreatment with clozapine blocked DOI-induced disruption of PPI. Altogether, these results suggest that serotonin-mediated mechanisms of the IC are involved in the expression of PPI in rodents and that this response is sensitive to atypical antipsychotic clozapine. Copyright © 2017 Elsevier B.V. All rights reserved.

Origin and function of short-latency inputs to the neural substrates underlying the acoustic startle reflex

PubMed Central

Gómez-Nieto, Ricardo; Horta-Júnior, José de Anchieta C.; Castellano, Orlando; Millian-Morell, Lymarie; Rubio, Maria E.; López, Dolores E.

2014-01-01

The acoustic startle reflex (ASR) is a survival mechanism of alarm, which rapidly alerts the organism to a sudden loud auditory stimulus. In rats, the primary ASR circuit encompasses three serially connected structures: cochlear root neurons (CRNs), neurons in the caudal pontine reticular nucleus (PnC), and motoneurons in the medulla and spinal cord. It is well-established that both CRNs and PnC neurons receive short-latency auditory inputs to mediate the ASR. Here, we investigated the anatomical origin and functional role of these inputs using a multidisciplinary approach that combines morphological, electrophysiological and behavioral techniques. Anterograde tracer injections into the cochlea suggest that CRNs somata and dendrites receive inputs depending, respectively, on their basal or apical cochlear origin. Confocal colocalization experiments demonstrated that these cochlear inputs are immunopositive for the vesicular glutamate transporter 1 (VGLUT1). Using extracellular recordings in vivo followed by subsequent tracer injections, we investigated the response of PnC neurons after contra-, ipsi-, and bilateral acoustic stimulation and identified the source of their auditory afferents. Our results showed that the binaural firing rate of PnC neurons was higher than the monaural, exhibiting higher spike discharges with contralateral than ipsilateral acoustic stimulations. Our histological analysis confirmed the CRNs as the principal source of short-latency acoustic inputs, and indicated that other areas of the cochlear nucleus complex are not likely to innervate PnC. Behaviorally, we observed a strong reduction of ASR amplitude in monaural earplugged rats that corresponds with the binaural summation process shown in our electrophysiological findings. Our study contributes to understand better the role of neuronal mechanisms in auditory alerting behaviors and provides strong evidence that the CRNs-PnC pathway mediates fast neurotransmission and binaural summation

The startle paradigm in a forensic psychiatric setting: elucidating psychopathy.

PubMed

Loomans, Max M; Tulen, Joke H M; van Marle, Hjalmar J C

2015-02-01

Most people who meet the diagnostic criteria for anti-social personality disorder (ASPD) do not meet the criteria for psychopathy. A differentiating feature is affective-interpersonal style. Eye blink startle reflex paradigms have been used to study affect. The aim of this study is to explore an eye blink startle paradigm as a means of distinguishing between men with both ASPD and psychopathy, and men with ASPD alone. One hundred and thirty-six men were recruited as follows: 31 patients with ASPD and a Psychopathy Checklist-Revised (PCL-R) score of 26 or more, 22 patients with ASPD and a PCL-R score of 25 or less, 50 forensic hospital employees and 33 general population men, none in the latter two groups having abnormal personality traits. Each was presented with 16 pleasant, 16 unpleasant and 16 neutral pictures. Acoustic probes were presented during each category at 300, 800, 1300 and 3800 milliseconds (ms) after picture onset. Eye blink response was measured by electromyography. Overall, both patient groups showed significantly smaller eye blink responses to the startle stimuli compared with the community controls. Both the latter and the ASPD group showed the expected increase in eye blink response at longer startle latencies to unpleasant pictures than pleasant pictures, but this was not present either in the group with psychopathy or in the forensic hospital employees. With increasing startle latency onset, eye blink amplitude increased significantly in both the healthy comparison groups and the ASPD group, but not in the group with psychopathy. We replicated eye blink startle modulation deficiencies among men with psychopathy. We confirmed that the psychopathy and ASPD groups could be distinguished by startle stimulus onset asynchrony, but this pattern was also seen in one healthy group - the forensic hospital employees. This suggests a case for more research with more diverse comparison groups and more differentiation of personality traits before drawing

Emotion regulation of the affect-modulated startle reflex during different picture categories.

PubMed

Conzelmann, Annette; McGregor, Victoria; Pauli, Paul

2015-09-01

Previous studies on emotion regulation of the startle reflex found an increase in startle amplitude from down-, to non-, to up-regulation for pleasant and unpleasant stimuli. We wanted to clarify whether this regulation effect remains stable for different picture categories within pleasant and unpleasant picture sets. We assessed startle amplitude of 31 participants during down-, non-, or up-regulation of feelings elicited by pleasant erotic and adventure and unpleasant victim and threat pictures. Startle amplitude was smaller during adventure and erotic compared to victim and threat pictures and increased from down-, to non-, to up-regulation independently of the picture category. Results indicate that the motivational priming effect on startle modulation elicited by different picture categories is independent of emotion regulation instructions. In addition, the emotion regulation effect is independent of motivational priming effects. © 2015 Society for Psychophysiological Research.

Nucleus accumbens carbachol disrupts olfactory and contextual fear-potentiated startle and attenuates baseline startle reactivity.

PubMed

Cousens, Graham A; Skrobacz, Cheryl G; Blumenthal, Anna

2011-01-20

Although the nucleus accumbens (NAc) typically is not considered a primary component of the circuitry underlying either the acquisition or retrieval of conditioned fear, evidence suggests that this region may play some role in modulating fear-related behaviors. The goal of the present study was to explore a potential role for NAc cholinergic receptors in the expression of fear-potentiated startle (FPS) and baseline startle reactivity. Intra-NAc infusion of the broad-acting cholinergic receptor agonist, carbachol, suppressed FPS elicited by re-exposure to both a discrete odor previously paired with footshock and the conditioning context. Although carbachol elevated spontaneous motor activity, activity bouts did not account for startle suppression in carbachol-treated Ss. In addition, intra-NAc carbachol suppressed baseline startle over a range of acoustic pulse intensities in the absence of explicit fear conditioning. Collectively, these findings suggest that NAc cholinergic receptors play a role in the modulation of baseline startle reactivity, rather than in the retrieval of learned fear, and that this role is independent of overt motor activity. Copyright © 2010 Elsevier B.V. All rights reserved.

Atypical antipsychotic olanzapine reversed deficit on prepulse inhibition of the acoustic startle reflex produced by microinjection of dizocilpine (MK-801) into the inferior colliculus in rats.

PubMed

Zangrando, Julia; Carvalheira, Renata; Labbate, Giovanna; Medeiros, Priscila; Longo, Beatriz Monteiro; Melo-Thomas, Liana; Silva, Regina Claudia Barbosa

2013-11-15

Patients with schizophrenia exhibit deficits in an operational measure of sensorimotor gating: prepulse inhibition (PPI) of startle. PPI is the normal reduction in the startle response caused by a low intensity non-startling stimulus (prepulse) which is presented shortly before the startle stimulus (pulse). MK-801 is an NMDA receptor-antagonist known to produce hyperactivity, deficits in prepulse inhibition and social withdrawal, behaviors which correlate well with some of the positive, cognitive and negative symptoms of schizophrenia. The inferior colliculus (IC) is a critical part of the auditory pathway mediating acoustic PPI. The activation of the IC by the acoustic prepulse reduces startle magnitude. Thus, the purpose of the present study was to elucidate the role of glutamatergic transmission in the IC on the expression of acoustic PPI. For that we investigated whether NMDA receptor stimulation or blockade would affect this response. Unilateral microinjections of NMDA (30 nmol/0.5 μL) into the IC did not alter PPI while microinjections of MK-801 (30 nmol/0.5 μL) into this structure disrupted PPI. We also examined the ability of the atypical antipsychotic olanzapine (5.0mg/kg; i.p.) to reverse the disruption of pre-pulse inhibition produced by unilateral microinjections of MK-801 into the IC of rats. Pretreatment with olanzapine blocked MK-801-induced disruption of PPI. Altogether, these results suggest that glutamate-mediated mechanisms of the IC are involved in the expression of PPI in rodents and that this response is sensitive to atypical antipsychotic olanzapine. Copyright © 2013 Elsevier B.V. All rights reserved.

Habituation in acoustic startle reflex: individual differences in personality.

PubMed

Blanch, Angel; Balada, Ferran; Aluja, Anton

2014-03-01

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. Copyright © 2014 Elsevier B.V. All rights reserved.

Cardiac Modulation of Startle: Effects on Eye Blink and Higher Cognitive Processing

ERIC Educational Resources Information Center

Schulz, Andre; Reichert, Carolin F.; Richter, Steffen; Lass-Hennemann, Johanna; Blumenthal, Terry D.; Schachinger, Hartmut

2009-01-01

Cardiac cycle time has been shown to affect pre-attentive brainstem startle processes, such as the magnitude of acoustically evoked reflexive startle eye blinks. These effects were attributed to baro-afferent feedback mechanisms. However, it remains unclear whether cardiac cycle time plays a role in higher startle-related cognitive processes, as…

Elevated Acoustic Startle Responses in Humans: Relationship to Reduced Loudness Discomfort Level, but not Self-Report of Hyperacusis.

PubMed

Knudson, Inge M; Melcher, Jennifer R

2016-06-01

Increases in the acoustic startle response (ASR) of animals have been reported following experimental manipulations to induce tinnitus, an auditory disorder defined by phantom perception of sound. The increases in ASR have been proposed to signify the development of hyperacusis, a clinical condition defined by intolerance of normally tolerable sound levels. To test this proposal, the present study compared ASR amplitude to measures of sound-level tolerance (SLT) in humans, the only species in which SLT can be directly assessed. Participants had clinically normal/near-normal hearing thresholds, were free of psychotropic medications, and comprised people with tinnitus and without. ASR was measured as eyeblink-related electromyographic activity in response to a noise pulse presented at a range of levels and in two background conditions (noise and quiet). SLT was measured as loudness discomfort level (LDL), the lowest level of sound deemed uncomfortable, and via a questionnaire on the loudness of sounds in everyday life. Regardless of tinnitus status, ASR amplitude at a given stimulus level increased with decreasing LDL, but showed no relationship to SLT self-reported via the questionnaire. These relationships (or lack thereof) could not be attributed to hearing threshold, age, anxiety, or depression. The results imply that increases in ASR in the animal work signify decreases in LDL specifically and may not correspond to the development of hyperacusis as would be self-reported by a clinic patient.

Cardiopulmonary baroreceptors affect reflexive startle eye blink.

PubMed

Richter, S; Schulz, A; Port, J; Blumenthal, T D; Schächinger, H

2009-12-07

Baroafferent signals originating from the 'high pressure' arterial vascular system are known to impact reflexive startle eye blink responding. However, it is not known whether baroafferent feedback of the 'low pressure' cardiopulmonary system loading status exerts a similar effect. Lower Body Negative Pressure (LBNP) at gradients of 0, -10, -20, and -30mm Hg was applied to unload cardiopulmonary baroreceptors. Acoustic startle noise bursts were delivered 230 and 530ms after spontaneous R-waves, when arterial baroreceptors are either loaded or unloaded. Eye blink responses were measured by EMG, and psychomotor reaction time by button pushes to startle stimuli. The new finding of this study was that unloading of cardiopulmonary baroreceptors increases startle eye blink responsiveness. Furthermore, we replicated the effect of relative loading/unloading of arterial baroreceptors on startle eye blink responsiveness. Effects of either arterial or cardiopulmonary baroreceptor manipulations were not present for psychomotor reaction times. These results demonstrate that the loading status of cardiopulmonary baroreceptors has an impact on brainstem-based CNS processes.

Somatostatin-28 modulates prepulse inhibition of the acoustic startle response, reward processes and spontaneous locomotor activity in rats

PubMed Central

Semenova, Svetlana; Hoyer, Daniel; Geyer, Mark A.; Markou, Athina

2011-01-01

Somatostatins have been shown to be involved in the pathophysiology of motor and affective disorders, as well as psychiatry disorders, including schizophrenia. We hypothesized that in addition to motor function, somatostatin may be involved in somatosensory gating and reward processes that have been shown to be dysregulated in schizophrenia. Accordingly, we evaluated the effects of intracerebroventricular administration of somatostatin-28 on spontaneous locomotor and exploratory behavior measured in a behavioral pattern monitor, sensorimotor gating, prepulse inhibition (PPI) of the acoustic startle reflex, and brain reward function (measured in a discrete trial intracranial self-stimulation procedure) in rats. Somatostatin-28 decreased spontaneous locomotor activity during the first 10 min of a 60 min testing session with no apparent changes in the exploratory activity of rats. The highest somatostatin-28 dose (10 μg/5 μl/side) induced PPI deficits with no effect on the acoustic startle response or startle response habituation. The somatostatin-induced PPI deficit was partially reversed by administration of SRA-880, a selective somatostatin 1 (sst1) receptor antagonist. Somatostatin-28 also induced elevations in brain reward thresholds, reflecting an anhedonic-like state. SRA-880 had no effect on brain reward function under baseline conditions. Altogether these findings suggest that somatostatin-28 modulates PPI and brain reward function but does not have a robust effect on spontaneous exploratory activity. Thus, increases in somatostatin transmission may represent one of the neurochemical mechanisms underlying anhedonia, one of the negative symptoms of schizophrenia, and sensorimotor gating deficits associated with cognitive impairments in schizophrenia patients. PMID:20537385

Peritraumatic startle response predicts the vulnerability to develop PTSD-like behaviors in rats: a model for peritraumatic dissociation

PubMed Central

Dong, Xinwen; Li, Yonghui

2014-01-01

Peritraumatic dissociation, a state characterized by alteration in perception and reduced awareness of surroundings, is considered to be a risk factor for the development of post-traumatic stress disorder (PTSD). However, the predictive ability of peritraumatic dissociation is questioned for the inconsistent results in different time points of assessment. The startle reflex is an objective behavioral measurement of defensive response to abrupt and intense sensory stimulus of surroundings, with potential to be used as an assessment on the dissociative status in both humans and rodents. The present study examined the predictive effect of acoustic startle response (ASR) in different time points around the traumatic event in an animal model of PTSD. The PTSD-like symptoms, including hyperarousal, avoidance, and contextual fear, were assessed 2–3 weeks post-trauma. The results showed that (1) the startle amplitude attenuated immediate after intense footshock in almost half of the stress animals, and (2) the attenuated startle responses at 1 h but not 24 h after stress predicted the development of severe PTSD-like symptoms. These data indicate that the startle alteration at the immediate period after trauma, including 1 h, is more important in PTSD prediction than 24 h after trauma. Our study also suggests that the startle attenuation immediate after intense stress may serve as an objective measurement of peritraumatic dissociation in rats. PMID:24478660

PYRETHROID INSECTICIDES AND THE GAMMA-AMINOBUTYRIC ACID (ALPHA) RECEPTOR COMPLEX: MOTOR ACTIVITY AND THE ACOUSTIC STARTLE RESPONSE IN THE RAT (JOURNAL VERSION)

EPA Science Inventory

Two behavioral tests, locomotor activity and the acoustic startle response (ASR), were utilized to test for dose-addition of cismethrin, a Type I, or deltamethrin, a Type II pyrethroid, with compounds active to the gamma-aminobutryic acid (GABA) receptor complex (picrotoxin, musc...

Modeling startle eyeblink electromyogram to assess fear learning.

PubMed

Khemka, Saurabh; Tzovara, Athina; Gerster, Samuel; Quednow, Boris B; Bach, Dominik R

2017-02-01

Pavlovian fear conditioning is widely used as a laboratory model of associative learning in human and nonhuman species. In this model, an organism is trained to predict an aversive unconditioned stimulus from initially neutral events (conditioned stimuli, CS). In humans, fear memory is typically measured via conditioned autonomic responses or fear-potentiated startle. For the latter, various analysis approaches have been developed, but a systematic comparison of competing methodologies is lacking. Here, we investigate the suitability of a model-based approach to startle eyeblink analysis for assessment of fear memory, and compare this to extant analysis strategies. First, we build a psychophysiological model (PsPM) on a generic startle response. Then, we optimize and validate this PsPM on three independent fear-conditioning data sets. We demonstrate that our model can robustly distinguish aversive (CS+) from nonaversive stimuli (CS-, i.e., has high predictive validity). Importantly, our model-based approach captures fear-potentiated startle during fear retention as well as fear acquisition. Our results establish a PsPM-based approach to assessment of fear-potentiated startle, and qualify previous peak-scoring methods. Our proposed model represents a generic startle response and can potentially be used beyond fear conditioning, for example, to quantify affective startle modulation or prepulse inhibition of the acoustic startle response. © 2016 The Authors. Psychophysiology published by Wiley Periodicals, Inc. on behalf of Society for Psychophysiological Research.

High doses of salicylate causes prepulse facilitation of onset-gap induced acoustic startle response.

PubMed

Sun, Wei; Doolittle, Lauren; Flowers, Elizabeth; Zhang, Chao; Wang, Qiuju

2014-01-01

Prepulse inhibition of acoustic startle reflex (PPI), a well-established method for evaluating sensorimotor gating function, has been used to detect tinnitus in animal models. Reduced gap induced PPI (gap-PPI) was considered as a sign of tinnitus. The silent gap used in the test contains both onset and offset signals. Tinnitus may affect these cues differently. In this experiment, we studied the effects of a high dose of salicylate (250 mg/kg, i.p.), an inducer of reversible tinnitus and sensorineural hearing loss, on gap-PPI induced by three different gaps: an onset-gap with 0.1 ms onset and 25 ms offset time, an offset-gap with 25 ms onset and 0.1 ms offset time, and an onset-offset-gap with 0.1 ms onset and offset time. We found that the onset-gaps induced smaller inhibitions than the offset-gaps before salicylate treatment. The offset-gap induced PPI was significantly reduced 1-3h after salicylate treatment. However, the onset-gap caused a facilitation of startle response. These results suggest that salicylate induced reduction of gap-PPI was not only caused by the decrease of offset-gap induced PPI, but also by the facilitation induced by the onset-gap. Since the onset-gap induced PPI is caused by neural offset response, our results suggest that salicylate may cause a facilitation of neural response to an offset acoustical signal. Treatment of vigabatrin (60 mg/kg/day, 14 days), which elevates the GABA level in the brain, blocked the offset-gap induced PPI and onset-gap induced facilitation caused by salicylate. These results suggest that enhancing GABAergic activities can alleviate salicylate induced tinnitus. Published by Elsevier B.V.

Startle reduces recall of a recently learned internal model.

PubMed

Wright, Zachary; Patton, James L; Ravichandran, Venn

2011-01-01

Recent work has shown that preplanned motor programs are released early from subcortical areas by the using a startling acoustic stimulus (SAS). Our question is whether this response might also contain a recently learned internal model, which draws on experience to predict and compensate for expected perturbations in a feedforward manner. Studies of adaptation to robotic forces have shown some evidence of this, but were potentially confounded by cocontraction caused by startle. We performed a new adaptation experiment using a visually distorted field that could not be confounded by cocontraction. We found that in all subjects that exhibited startle, the startle stimulus (1) reduced performance of the recently learned task (2) reduced after-effect magnitudes. Because startle reduced but did not eliminate the recall of learned control, we suggest that multiple neural centers (cortical and subcortical) are involved in such learning and adaptation, which can impact training areas such as piloting, teleoperation, sports, and rehabilitation. © 2011 IEEE

Anger and aggression problems in veterans are associated with an increased acoustic startle reflex.

PubMed

Heesink, Lieke; Kleber, Rolf; Häfner, Michael; van Bedaf, Laury; Eekhout, Iris; Geuze, Elbert

2017-02-01

Anger and aggression are frequent problems in deployed military personnel. A lowered threshold of perceiving and responding to threat can trigger impulsive aggression. This can be indicated by an exaggerated startle response. Fifty-two veterans with anger and aggression problems (Anger group) and 50 control veterans were tested using a startle experiment with 10 startle probes and 10 prepulse trials, presented in a random order and with a random interval between the trials. Predictors (demographics, Trait Anger, State Anger, Harm Avoidance and Anxious Arousal) for the startle response within the Anger group were tested. Increased EMG responses were found to the startle probes in the Anger Group compared to the Control group, but not to the prepulse trials. Furthermore, Harm Avoidance and State Anger predicted the increased startle reflex within the Anger group, whereas Trait Anger was negatively related to the startle reflex. These findings indicate that threat reactivity is increased in anger and aggression problems. These problems are not only caused by an anxious predisposition, the degree of anger also predicts the startle reflex. Copyright © 2016 Elsevier B.V. All rights reserved.

Oxytocin Reduces Background Anxiety in a Fear-Potentiated Startle Paradigm: Peripheral vs Central Administration

PubMed Central

Ayers, Luke W; Missig, Galen; Schulkin, Jay; Rosen, Jeffrey B

2011-01-01

Oxytocin is known to have anti-anxiety and anti-stress effects. Using a fear-potentiated startle paradigm in rats, we previously demonstrated that subcutaneously administered oxytocin suppressed acoustic startle following fear conditioning compared with startle before fear conditioning (termed background anxiety), but did not have an effect on cue-specific fear-potentiated startle. The findings suggest oxytocin reduces background anxiety, an anxious state not directly related to cue-specific fear, but sustained beyond the immediate threat. The goal of the present study was to compare the effects of centrally and peripherally administered oxytocin on background anxiety and cue-specific fear. Male rats were given oxytocin either subcutaneously (SC) or intracerebroventricularly (ICV) into the lateral ventricles before fear-potentiated startle testing. Oxytocin doses of 0.01 and 0.1 μg/kg SC reduced background anxiety. ICV administration of oxytocin at doses from 0.002 to 20 μg oxytocin had no effect on background anxiety or cue-specific fear-potentiated startle. The 20 μg ICV dose of oxytocin did reduce acoustic startle in non-fear conditioned rats. These studies indicate that oxytocin is potent and effective in reducing background anxiety when delivered peripherally, but not when delivered into the cerebroventricular system. Oxytocin given systemically may have anti-anxiety properties that are particularly germane to the hypervigilance and exaggerated startle typically seen in many anxiety and mental health disorder patients. PMID:21796104

Effect of stress and attention on startle response and prepulse inhibition.

PubMed

De la Casa, Luis Gonzalo; Mena, Auxiliadora; Ruiz-Salas, Juan Carlos

2016-10-15

The startle reflex magnitude can be modulated when a weak stimulus is presented before the onset of the startle stimulus, a phenomenon termed prepulse inhibition (PPI). Previous research has demonstrated that emotional processes can modulate PPI and startle intensity, but the available evidence is inconclusive. In order to obtain additional evidence in this domain, we conducted two experiments intended to analyze the effect of induced stress and attentional load on PPI and startle magnitude. Specifically, in Experiment 1 we used a between subject strategy to evaluate the effect on startle response and PPI magnitude of performing a difficult task intended to induce stress in the participants, as compared to a group exposed to a control task. In Experiment 2 we evaluated the effect of diverting attention from the acoustic stimulus on startle and PPI intensity. The results seem to indicate that induced stress can reduce PPI, and that startle reflex intensity is reduced when attention is directed away from the auditory stimulus that induces the reflex. Copyright © 2016 Elsevier Inc. All rights reserved.

History of chronic stress modifies acute stress-evoked fear memory and acoustic startle in male rats.

PubMed

Schmeltzer, Sarah N; Vollmer, Lauren L; Rush, Jennifer E; Weinert, Mychal; Dolgas, Charles M; Sah, Renu

2015-01-01

Chronicity of trauma exposure plays an important role in the pathophysiology of posttraumatic stress disorder (PTSD). Thus, exposure to multiple traumas on a chronic scale leads to worse outcomes than acute events. The rationale for the current study was to investigate the effects of a single adverse event versus the same event on a background of chronic stress. We hypothesized that a history of chronic stress would lead to worse behavioral outcomes than a single event alone. Male rats (n = 14/group) were exposed to either a single traumatic event in the form of electric foot shocks (acute shock, AS), or to footshocks on a background of chronic stress (chronic variable stress-shock, CVS-S). PTSD-relevant behaviors (fear memory and acoustic startle responses) were measured following 7 d recovery. In line with our hypothesis, CVS-S elicited significant increases in fear acquisition and conditioning versus the AS group. Unexpectedly, CVS-S elicited reduced startle reactivity to an acoustic stimulus in comparison with the AS group. Significant increase in FosB/ΔFosB-like immunostaining was observed in the dentate gyrus, basolateral amygdala and medial prefrontal cortex of CVS-S rats. Assessments of neuropeptide Y (NPY), a stress-regulatory transmitter associated with chronic PTSD, revealed selective reduction in the hippocampus of CVS-S rats. Collectively, our data show that cumulative stress potentiates delayed fear memory and impacts defensive responding. Altered neuronal activation in forebrain limbic regions and reduced NPY may contribute to these phenomena. Our preclinical studies support clinical findings reporting worse PTSD outcomes stemming from cumulative traumatization in contrast to acute trauma.

Meditation and the Startle Response: A Case Study

PubMed Central

Levenson, Robert W.; Ekman, Paul; Ricard, Matthieu

2013-01-01

The effects of two kinds of meditation (open presence and focused) on the facial and physiological aspects of the defensive response to an aversive startle stimulus were studied in a Buddhist monk with approximately 40 years of meditation experience. The participant was exposed to a 115 db, 100 ms acoustic startle stimulus under the two meditation conditions, a distraction condition (to control for cognitive and attentional load) and an unanticipated condition (startle presented without warning or instruction). A completely counterbalanced 24-trial single-subject design was used, with each condition repeated six times. Most aspects of the participant’s responses in the unanticipated condition did not differ from those of a comparison group of 12 age-matched male controls. Both kinds of meditation produced physiological and facial responses to the startle that were smaller than in the distraction condition. Within meditation conditions, open presence meditation produced smaller physiological and facial responses than focused meditation. These results from a single highly expert meditator indicate that these two kinds of meditation can differentially alter the magnitude of a primitive defensive response. PMID:22506498

Degraded expression of learned feedforward control in movements released by startle.

PubMed

Wright, Zachary A; Carlsen, Anthony N; MacKinnon, Colum D; Patton, James L

2015-08-01

Recent work has shown that preplanned motor programs can be rapidly released via fast conducting pathways using a startling acoustic stimulus. Our question was whether the startle-elicited response might also release a recently learned internal model, which draws on experience to predict and compensate for expected perturbations in a feedforward manner. Our initial investigation using adaptation to robotically produced forces showed some evidence of this, but the results were potentially confounded by co-contraction caused by startle. In this study, we eliminated this confound by asking subjects to make reaching movements in the presence of a visual distortion. Results show that a startle stimulus (1) decreased performance of the recently learned task and (2) reduced after-effect magnitude. Since the recall of learned control was reduced, but not eliminated during startle trials, we suggest that multiple neural centers (cortical and subcortical) are involved in such learning and adaptation. These findings have implications for motor training in areas such as piloting, teleoperation, sports, and rehabilitation.

Appetitive startle modulation in the human laboratory predicts Cannabis craving in the natural environment.

PubMed

Mereish, Ethan H; Padovano, Hayley Treloar; Wemm, Stephanie; Miranda, Robert

2018-07-01

Drug-related cues evoke craving and stimulate motivational systems in the brain. The acoustic startle reflex captures activation of these motivational processes and affords a unique measure of reactivity to drug cues. This study examined the effects of cannabis-related cues on subjective and eye blink startle reactivity in the human laboratory and tested whether these effects predicted youth's cue-elicited cannabis craving in the natural environment. Participants were 55 frequent cannabis users, ages 16 to 24 years (M = 19.9, SD = 1.9; 55% male; 56% met criteria for cannabis dependence), who were recruited from a clinical trial to reduce cannabis use. Eye blink electromyographic activity was recorded in response to acoustic probes that elicited startle reactivity while participants viewed pleasant, unpleasant, neutral, and cannabis picture cues. Following the startle assessment, participants completed an ecological momentary assessment protocol that involved repeated assessments of cue-elicited craving in real time in their real-world environments. Multilevel models included the presence or absence of visible cannabis cues in the natural environment, startle magnitude, and the cross-level interaction of cues by startle to test whether cue-modulated startle reactivity in the laboratory was associated with cue-elicited craving in the natural environment. Analyses showed that cannabis-related stimuli evoked an appetitive startle response pattern in the laboratory, and this effect was associated with increased cue-elicited craving in the natural environment, b = - 0.15, p = .022, 95% CI [- 0.28, - 0.02]. Pleasant stimuli also evoked an appetitive response pattern, but in this case, blunted response was associated with increased cue-elicited craving in the natural environment, b = 0.27, p < .001, 95% CI [0.12, 0.43]. Our findings support cue-modulated startle reactivity as an index of the phenotypic expression of cue-elicited cannabis craving.

A Shock-Refracted Acoustic Wave Model for Screech Amplitude in Supersonic Jets

NASA Technical Reports Server (NTRS)

Kandula, Max

2007-01-01

A physical model is proposed for the estimation of the screech amplitude in underexpanded supersonic jets. The model is based on the hypothesis that the interaction of a plane acoustic wave with stationary shock waves provides amplification of the transmitted acoustic wave upon traversing the shock. Powell's discrete source model for screech incorporating a stationary array of acoustic monopoles is extended to accommodate variable source strength. The proposed model reveals that the acoustic sources are of increasing strength with downstream distance. It is shown that the screech amplitude increases with the fully expanded jet Mach number. Comparisons of predicted screech amplitude with available test data show satisfactory agreement. The effect of variable source strength on the directivity of the fundamental (first harmonic, lowest frequency mode) and the second harmonic (overtone) is found to be unimportant with regard to the principal lobe (main or major lobe) of considerable relative strength, and is appreciable only in the secondary or minor lobes (of relatively weaker strength).

High amplitude nonlinear acoustic wave driven flow fields in cylindrical and conical resonators.

PubMed

Antao, Dion Savio; Farouk, Bakhtier

2013-08-01

A high fidelity computational fluid dynamic model is used to simulate the flow, pressure, and density fields generated in a cylindrical and a conical resonator by a vibrating end wall/piston producing high-amplitude standing waves. The waves in the conical resonator are found to be shock-less and can generate peak acoustic overpressures that exceed the initial undisturbed pressure by two to three times. A cylindrical (consonant) acoustic resonator has limitations to the output response observed at one end when the opposite end is acoustically excited. In the conical geometry (dissonant acoustic resonator) the linear acoustic input is converted to high energy un-shocked nonlinear acoustic output. The model is validated using past numerical results of standing waves in cylindrical resonators. The nonlinear nature of the harmonic response in the conical resonator system is further investigated for two different working fluids (carbon dioxide and argon) operating at various values of piston amplitude. The high amplitude nonlinear oscillations observed in the conical resonator can potentially enhance the performance of pulse tube thermoacoustic refrigerators and these conical resonators can be used as efficient mixers.

Airborne Acoustic Perception by a Jumping Spider.

PubMed

Shamble, Paul S; Menda, Gil; Golden, James R; Nitzany, Eyal I; Walden, Katherine; Beatus, Tsevi; Elias, Damian O; Cohen, Itai; Miles, Ronald N; Hoy, Ronald R

2016-11-07

Jumping spiders (Salticidae) are famous for their visually driven behaviors [1]. Here, however, we present behavioral and neurophysiological evidence that these animals also perceive and respond to airborne acoustic stimuli, even when the distance between the animal and the sound source is relatively large (∼3 m) and with stimulus amplitudes at the position of the spider of ∼65 dB sound pressure level (SPL). Behavioral experiments with the jumping spider Phidippus audax reveal that these animals respond to low-frequency sounds (80 Hz; 65 dB SPL) by freezing-a common anti-predatory behavior characteristic of an acoustic startle response. Neurophysiological recordings from auditory-sensitive neural units in the brains of these jumping spiders showed responses to low-frequency tones (80 Hz at ∼65 dB SPL)-recordings that also represent the first record of acoustically responsive neural units in the jumping spider brain. Responses persisted even when the distances between spider and stimulus source exceeded 3 m and under anechoic conditions. Thus, these spiders appear able to detect airborne sound at distances in the acoustic far-field region, beyond the near-field range often thought to bound acoustic perception in arthropods that lack tympanic ears (e.g., spiders) [2]. Furthermore, direct mechanical stimulation of hairs on the patella of the foreleg was sufficient to generate responses in neural units that also responded to airborne acoustic stimuli-evidence that these hairs likely play a role in the detection of acoustic cues. We suggest that these auditory responses enable the detection of predators and facilitate an acoustic startle response. VIDEO ABSTRACT. Copyright © 2016 Elsevier Ltd. All rights reserved.

Methodological optimization of tinnitus assessment using prepulse inhibition of the acoustic startle reflex.

PubMed

Longenecker, R J; Galazyuk, A V

2012-11-16

Recently prepulse inhibition of the acoustic startle reflex (ASR) became a popular technique for tinnitus assessment in laboratory animals. This method confers a significant advantage over the previously used time-consuming behavioral approaches utilizing basic mechanisms of conditioning. Although this technique has been successfully used to assess tinnitus in different laboratory animals, many of the finer details of this methodology have not been described enough to be replicated, but are critical for tinnitus assessment. Here we provide detail description of key procedures and methodological issues that provide guidance for newcomers with the process of learning to correctly apply gap detection techniques for tinnitus assessment in laboratory animals. The major categories of these issues include: refinement of hardware for best performance, optimization of stimulus parameters, behavioral considerations, and identification of optimal strategies for data analysis. This article is part of a Special Issue entitled: Tinnitus Neuroscience. Copyright © 2012. Published by Elsevier B.V.

Startle reveals an absence of advance motor programming in a Go/No-go task.

PubMed

Carlsen, Anthony N; Chua, Romeo; Dakin, Chris J; Sanderson, David J; Inglis, J Timothy; Franks, Ian M

2008-03-21

Presenting a startling stimulus in a simple reaction time (RT) task, can involuntarily trigger the pre-programmed response. However, this effect is not seen when the response is programmed following the imperative stimulus (IS) providing evidence that a startle can only trigger pre-programmed responses. In a "Go/No-go" (GNG) RT task the response may be programmed in advance of the IS because there exists only a single predetermined response. The purpose of the current investigation was to examine if startle could elicit a response in a GNG task. Participants completed a wrist extension task in response to a visual stimulus. A startling acoustic stimulus (124dB) was presented in both Go and No-go trials with Go probability manipulated between groups. The inclusion of a startle did not significantly speed RT and led to more response errors. This result is similar to that observed in a startled choice RT task, indicating that in a GNG task participants waited until the IS complete motor programming.

Nonlinear ionospheric responses to large-amplitude infrasonic-acoustic waves generated by undersea earthquakes

NASA Astrophysics Data System (ADS)

Zettergren, M. D.; Snively, J. B.; Komjathy, A.; Verkhoglyadova, O. P.

2017-02-01

Numerical models of ionospheric coupling with the neutral atmosphere are used to investigate perturbations of plasma density, vertically integrated total electron content (TEC), neutral velocity, and neutral temperature associated with large-amplitude acoustic waves generated by the initial ocean surface displacements from strong undersea earthquakes. A simplified source model for the 2011 Tohoku earthquake is constructed from estimates of initial ocean surface responses to approximate the vertical motions over realistic spatial and temporal scales. Resulting TEC perturbations from modeling case studies appear consistent with observational data, reproducing pronounced TEC depletions which are shown to be a consequence of the impacts of nonlinear, dissipating acoustic waves. Thermospheric acoustic compressional velocities are ˜±250-300 m/s, superposed with downward flows of similar amplitudes, and temperature perturbations are ˜300 K, while the dominant wave periodicity in the thermosphere is ˜3-4 min. Results capture acoustic wave processes including reflection, onset of resonance, and nonlinear steepening and dissipation—ultimately leading to the formation of ionospheric TEC depletions "holes"—that are consistent with reported observations. Three additional simulations illustrate the dependence of atmospheric acoustic wave and subsequent ionospheric responses on the surface displacement amplitude, which is varied from the Tohoku case study by factors of 1/100, 1/10, and 2. Collectively, results suggest that TEC depletions may only accompany very-large amplitude thermospheric acoustic waves necessary to induce a nonlinear response, here with saturated compressional velocities ˜200-250 m/s generated by sea surface displacements exceeding ˜1 m occurring over a 3 min time period.

Between Site Reliability of Startle Prepulse Inhibition Across Two Early Psychosis Consortia

PubMed Central

Addington, Jean; Cannon, Tyrone D.; Cornblatt, Barbara A.; de la Fuente-Sandoval, Camilo; Mathalon, Dan H.; Perkins, Diana O.; Seidman, Larry J.; Tsuang, Ming; Walker, Elaine F.; Woods, Scott W.; Bachman, Peter; Belger, Ayse; Carrión, Ricardo E.; Donkers, Franc C.L.; Duncan, Erica; Johannesen, Jason; León-Ortiz, Pablo; Light, Gregory; Mondragón, Alejandra; Niznikiewicz, Margaret; Nunag, Jason; Roach, Brian J.; Solís-Vivanco, Rodolfo

2014-01-01

Prepulse inhibition (PPI) and reactivity of the acoustic startle response are widely used biobehavioral markers in psychopathology research. Previous studies have demonstrated that PPI and startle reactivity exhibit substantial within-site stability; between-site stability, however, has not been established. In two separate consortia investigating biomarkers of early psychosis, traveling subjects studies were performed as part of quality assurance procedures in order to assess the fidelity of data across sites. In the North American Prodromal Longitudinal Studies (NAPLS) Consortium, 8 normal subjects traveled to each of the 8 NAPLS sites and were tested twice at each site on the startle PPI paradigm. In preparation for a binational study, 10 healthy subjects were assessed twice in both San Diego and Mexico City. Intraclass correlations between and within sites were significant for PPI and startle response parameters, confirming the reliability of startle measures across sites in both consortia. There were between site differences in startle magnitude in the NAPLS study that did not appear to be related to methods or equipment. In planning multi-site studies, it is essential to institute quality assurance procedures early and establish between site reliability to assure comparable data across sites. PMID:23799460

Amplitude Modulations of Acoustic Communication Signals

NASA Astrophysics Data System (ADS)

Turesson, Hjalmar K.

2011-12-01

In human speech, amplitude modulations at 3 -- 8 Hz are important for discrimination and detection. Two different neurophysiological theories have been proposed to explain this effect. The first theory proposes that, as a consequence of neocortical synaptic dynamics, signals that are amplitude modulated at 3 -- 8 Hz are propagated better than un-modulated signals, or signals modulated above 8 Hz. This suggests that neural activity elicited by vocalizations modulated at 3 -- 8 Hz is optimally transmitted, and the vocalizations better discriminated and detected. The second theory proposes that 3 -- 8 Hz amplitude modulations interact with spontaneous neocortical oscillations. Specifically, vocalizations modulated at 3 -- 8 Hz entrain local populations of neurons, which in turn, modulate the amplitude of high frequency gamma oscillations. This suggests that vocalizations modulated at 3 -- 8 Hz should induce stronger cross-frequency coupling. Similar to human speech, we found that macaque monkey vocalizations also are amplitude modulated between 3 and 8 Hz. Humans and macaque monkeys share similarities in vocal production, implying that the auditory systems subserving perception of acoustic communication signals also share similarities. Based on the similarities between human speech and macaque monkey vocalizations, we addressed how amplitude modulated vocalizations are processed in the auditory cortex of macaque monkeys, and what behavioral relevance modulations may have. Recording single neuron activity, as well as, the activity of local populations of neurons allowed us to test both of the neurophysiological theories presented above. We found that single neuron responses to vocalizations amplitude modulated at 3 -- 8 Hz resulted in better stimulus discrimination than vocalizations lacking 3 -- 8 Hz modulations, and that the effect most likely was mediated by synaptic dynamics. In contrast, we failed to find support for the oscillation-based model proposing a

Effects of oxytocin on background anxiety in rats with high or low baseline startle

PubMed Central

Ayers, Luke; Agostini, Andrew; Schulkin, Jay; Rosen, Jeffrey B.

2016-01-01

Rationale Oxytocin has antianxiety properties in humans and rodents. However, the antianxiety effects have been variable. Objectives To reduce variability and strengthen to the antianxiety effect of oxytocin in fear-potentiated startle, two experiments were performed. First, different amounts of light-shock pairings were given to determine the optimal levels of cue-specific fear conditioning and non-predictable startle (background anxiety). Second, the antianxiety effects of oxytocin were examined in rats with high and low pre-fear conditioning baseline startle to determine if oxytocin differentially affects high and low trait anxiety rats. Methods Baseline pre-fear conditioning startle responses were first measured. Rats then received 1, 5 or 10 light-shock pairings. Fear-potentiated startle was then tested with two trial types: light-cued startle and non-cued startle trials. In the second experiment, rats fear conditioned with 10 light-shock pairings were administered either saline or oxytocin before a fear-potentiated startle test. Rats were categorized as low or high startlers by their pre-fear conditioning startle amplitude. Results Ten shock-pairings produced the largest non-cued startle responses (background anxiety), without increasing cue-specific fear-potentiated startle compared to 1 and 5 light-shock pairings. Cue-specific fear-potentiated startle was unaffected by oxytocin. Oxytocin reduced background anxiety only in rats with low pre-fear startle responses. Conclusions Oxytocin has population selective antianxiety effects on non-cued unpredictable threat, but only in rats with low pre-fear baseline startle responses. The low startle responses are reminiscent of humans with low startle responses and high trait anxiety. PMID:27004789

Predicting impaired extinction of traumatic memory and elevated startle.

PubMed

Nalloor, Rebecca; Bunting, Kristopher; Vazdarjanova, Almira

2011-01-01

Emotionally traumatic experiences can lead to debilitating anxiety disorders, such as phobias and Post-Traumatic Stress Disorder (PTSD). Exposure to such experiences, however, is not sufficient to induce pathology, as only up to one quarter of people exposed to such events develop PTSD. These statistics, combined with findings that smaller hippocampal size prior to the trauma is associated with higher risk of developing PTSD, suggest that there are pre-disposing factors for such pathology. Because prospective studies in humans are limited and costly, investigating such pre-dispositions, and thus advancing understanding of the genesis of such pathologies, requires the use of animal models where predispositions are identified before the emotional trauma. Most existing animal models are retrospective: they classify subjects as those with or without a PTSD-like phenotype long after experiencing a traumatic event. Attempts to create prospective animal models have been largely unsuccessful. Here we report that individual predispositions to a PTSD-like phenotype, consisting of impaired rate and magnitude of extinction of an emotionally traumatic event coupled with long-lasting elevation of acoustic startle responses, can be revealed following exposure to a mild stressor, but before experiencing emotional trauma. We compare, in rats, the utility of several classification criteria and report that a combination of criteria based on acoustic startle responses and behavior in an anxiogenic environment is a reliable predictor of a PTSD-like phenotype. There are individual predispositions to developing impaired extinction and elevated acoustic startle that can be identified after exposure to a mildly stressful event, which by itself does not induce such a behavioral phenotype. The model presented here is a valuable tool for studying the etiology and pathophysiology of anxiety disorders and provides a platform for testing behavioral and pharmacological interventions that can

Acoustic analog computing based on a reflective metasurface with decoupled modulation of phase and amplitude

NASA Astrophysics Data System (ADS)

Zuo, Shu-Yu; Tian, Ye; Wei, Qi; Cheng, Ying; Liu, Xiao-Jun

2018-03-01

The use of metasurfaces has allowed the provision of a variety of functionalities by ultrathin structures, paving the way toward novel highly compact analog computing devices. Here, we conceptually realize analog computing using an acoustic reflective computational metasurface (RCM) that can independently manipulate the reflection phase and amplitude of an incident acoustic signal. This RCM is composed of coating unit cells and perforated panels, where the first can tune the transmission phase within the full range of 2π and the second can adjust the reflection amplitude in the range of 0-1. We show that this RCM can achieve arbitrary reflection phase and amplitude and can be used to realize a unique linear spatially invariant transfer function. Using the spatial Fourier transform (FT), an acoustic analog computing (AAC) system is proposed based on the RCM together with a focusing lens. Based on numerical simulations, we demonstrate that this AAC system can perform mathematical operations such as spatial differentiation, integration, and convolution on an incident acoustic signal. The proposed system has low complexity and reduced size because the RCM is able to individually adjust the reflection phase and amplitude and because only one block is involved in performing the spatial FT. Our work may offer a practical, efficient, and flexible approach to the design of compact devices for acoustic computing applications, signal processing, equation solving, and acoustic wave manipulations.

A double-blind, placebo-controlled study on the effects of Gotu Kola (Centella asiatica) on acoustic startle response in healthy subjects.

PubMed

Bradwejn, J; Zhou, Y; Koszycki, D; Shlik, J

2000-12-01

Investigations of the pharmacologic profile of medicinal plants have revealed that a number of plants with purported anxiolytic activity bind to cholecystokinin (CCK) receptors. This finding is intriguing in view of the proposed involvement of CCK in the pathophysiology of fear and anxiety. This double-blind, placebo-controlled study was undertaken to evaluate the anxiolytic activity of Gotu Kola (Centella asiatica) in healthy subjects. Gotu Kola has been used for centuries in Ayurvedic and traditional Chinese medicine to alleviate symptoms of depression and anxiety. Recent studies in the rat have shown that long-term pretreatment with Gotu Kola decreases locomotor activity, enhances elevated-plus maze performance, and attenuates the acoustic startle response (ASR). In this study, the authors evaluated the effects of Gotu Kola on the ASR in humans. Subjects were randomly assigned to receive either a single 12-g orally administered dose of Gotu Kola (N = 20) or placebo (N = 20). The results revealed that compared with placebo, Gotu Kola significantly attenuated the peak ASR amplitude 30 and 60 minutes after treatment. Gotu Kola had no significant effect on self-rated mood, heart rate, or blood pressure. These preliminary findings suggest that Gotu Kola has anxiolytic activity in humans as revealed by the ASR. It remains to be seen whether this herb has therapeutic efficacy in the treatment of anxiety syndromes.

Oxytocin and Social Support as Synergistic Inhibitors of Aversive Fear Conditioning and Fear-Potentiated Startle in Male Rats

DTIC Science & Technology

2009-09-01

startle amplitude. They then received Pavlovian fear conditioning of five pairings of a 3 s light co-terminating with a 500 ms, 0.6mA footshock. Four...Synergistic Inhibitors of Aversive Fear Conditioning and Fear-Potentiated Startle in Male Rats PRINCIPAL INVESTIGATOR: Jeffrey B. Rosen, Ph.D...NUMBER Oxytocin and Social Support as Synergistic Inhibitors of Aversive Fear Conditioning and Fear-Potentiated Startle in Male Rats 5b. GRANT

A Shock-Refracted Acoustic Wave Model for the Prediction of Screech Amplitude in Supersonic Jets

NASA Technical Reports Server (NTRS)

Kandula, Max

2007-01-01

A physical model is proposed for the estimation of the screech amplitude in underexpanded supersonic jets. The model is based on the hypothesis that the interaction of a plane acoustic wave with stationary shock waves provides amplification of the transmitted acoustic wave upon traversing the shock. Powell's discrete source model for screech incorporating a stationary array of acoustic monopoles is extended to accommodate variable source strength. The proposed model reveals that the acoustic sources are of increasing strength with downstream distance. It is shown that the screech amplitude increases with the fuiiy expanded jet Mach number. Comparisons of predicted screech amplitude with available test data show satisfactory agreement. The effect of variable source strength on directivity of the fundamental (first harmonic, lowest frequency mode) and the second harmonic (overtone) is found to be unimportant with regard to the principal lobe (main or major lobe) of considerable relative strength, and is appreciable only in the secondary or minor lobes (of relatively weaker strength

Preimmunization with a heat-killed preparation of Mycobacterium vaccae enhances fear extinction in the fear-potentiated startle paradigm.

PubMed

Fox, James H; Hassell, James E; Siebler, Philip H; Arnold, Mathew R; Lamb, Andrew K; Smith, David G; Day, Heidi E W; Smith, Tessa M; Simmerman, Emma M; Outzen, Alexander A; Holmes, Kaley S; Brazell, Christopher J; Lowry, Christopher A

2017-11-01

The hygiene hypothesis or "Old Friends" hypothesis proposes that inflammatory diseases are increasing in modern urban societies, due in part to reduced exposure to microorganisms that drive immunoregulatory circuits, and a failure to terminate inappropriate inflammatory responses. Inappropriate inflammation is also emerging as a risk factor for trauma-related, anxiety, and affective disorders, including posttraumatic stress disorder (PTSD), which is characterized as persistent re-experiencing of the trauma after a traumatic experience. Traumatic experiences can lead to long-lasting fear memories and exaggerated fear potentiation of the acoustic startle reflex. The acoustic startle reflex is an ethologically relevant reflex and can be potentiated in both humans and rats through Pavlovian conditioning. Mycobacterium vaccae NCTC 11659 is a soil-derived bacterium with immunoregulatory and anti-inflammatory properties that has been demonstrated to confer stress resilience in mice. Here we immunized adult male Sprague Dawley rats 3×, once per week, with a heat-killed preparation of M. vaccae NCTC 11659 (0.1mg, s.c., in 100µl borate-buffered saline) or vehicle, and, then, 3weeks following the final immunization, tested them in the fear-potentiated startle paradigm; controls were maintained under home cage control conditions throughout the experiment (n=11-12 per group). Rats were tested on days 1 and 2 for baseline acoustic startle, received fear conditioning on days 3 and 4, and underwent fear extinction training on days 5-10. Rats were euthanized on day 11 and brain tissue was sectioned for analysis of mRNA expression for genes important in control of brain serotonergic signaling, including tph2, htr1a, slc6a4, and slc22a3, throughout the brainstem dorsal and median raphe nuclei. Immunization with M. vaccae had no effect on baseline acoustic startle or fear expression on day 5. However, M. vaccae-immunized rats showed enhanced between-session and within

Startle habituation, sensory, and sensorimotor gating in trauma-affected refugees with posttraumatic stress disorder.

PubMed

Meteran, Hanieh; Vindbjerg, Erik; Uldall, Sigurd Wiingaard; Glenthøj, Birte; Carlsson, Jessica; Oranje, Bob

2018-05-17

Impairments in mechanisms underlying early information processing have been reported in posttraumatic stress disorder (PTSD); however, findings in the existing literature are inconsistent. This current study capitalizes on technological advancements of research on electroencephalographic event-related potential and applies it to a novel PTSD population consisting of trauma-affected refugees. A total of 25 trauma-affected refugees with PTSD and 20 healthy refugee controls matched on age, gender, and country of origin completed the study. In two distinct auditory paradigms sensory gating, indexed as P50 suppression, and sensorimotor gating, indexed as prepulse inhibition (PPI), startle reactivity, and habituation of the eye-blink startle response were examined. Within the P50 paradigm, N100 and P200 amplitudes were also assessed. In addition, correlations between psychophysiological and clinical measures were investigated. PTSD patients demonstrated significantly elevated stimuli responses across the two paradigms, reflected in both increased amplitude of the eye-blink startle response, and increased N100 and P200 amplitudes relative to healthy refugee controls. We found a trend toward reduced habituation in the patients, while the groups did not differ in PPI and P50 suppression. Among correlations, we found that eye-blink startle responses were associated with higher overall illness severity and lower levels of functioning. Fundamental gating mechanisms appeared intact, while the pattern of deficits in trauma-affected refugees with PTSD point toward a different form of sensory overload, an overall neural hypersensitivity and disrupted the ability to down-regulate stimuli responses. This study represents an initial step toward elucidating sensory processing deficits in a PTSD subgroup.

Nonlinear properties of small amplitude dust ion acoustic solitary waves

NASA Astrophysics Data System (ADS)

Ghosh, Samiran; Sarkar, S.; Khan, Manoranjan; Gupta, M. R.

2000-09-01

In this paper some nonlinear characteristics of small amplitude dust ion acoustic solitary wave in three component dusty plasma consisting of electrons, ions, and dust grains have been studied. Simultaneously, the charge fluctuation dynamics of the dust grains under the assumption that the dust charging time scale is much smaller than the dust hydrodynamic time scale has been considered here. The ion dust collision has also been incorporated. It has been seen that a damped Korteweg-de Vries (KdV) equation governs the nonlinear dust ion acoustic wave. The damping arises due to ion dust collision, under the assumption that the ion hydrodynamical time scale is much smaller than that of the ion dust collision. Numerical investigations reveal that the dust ion acoustic wave admits only a positive potential, i.e., compressive soliton.

Sensorimotor Gating in Depressed and Euthymic Patients with Bipolar Disorder: Analysis on Prepulse Inhibition of Acoustic Startle Response Stratified by Gender and State.

PubMed

Matsuo, Junko; Ota, Miho; Hidese, Shinsuke; Teraishi, Toshiya; Hori, Hiroaki; Ishida, Ikki; Hiraishi, Moeko; Kunugi, Hiroshi

2018-01-01

Prepulse inhibition (PPI) of the acoustic startle reflex is an operational measure of sensorimotor gating. The findings on PPI deficits in bipolar disorder (BD) are inconsistent among studies due to various confounding factors such as gender. This study aimed to assess sensorimotor gating deficits in patients with BD stratified by gender and state (depressed/euthymic), and to explore related clinical variables. Subjects were 106 non-manic BD patients (26 BD I and 80 BD II; 63 with depression and 43 euthymic) and 232 age-, gender-, and ethnicity-matched (Japanese) healthy controls. Depression severity was assessed using the Hamilton Depression Rating Scale-21. The electromyographic activity of the orbicularis oculi muscle was measured by a computerized startle reflex test unit. Startle magnitude, habituation, and PPI were compared among the three clinical groups: depressed BD, euthymic BD, and healthy controls. In a second analysis, patients were divided into four groups using the quartile PPI levels of controls of each gender, and a ratio of the low-PPI group (<1st quartile of controls) was compared. Effects of psychosis and medication status were examined by the Mann-Whitney U test. Clinical correlates such as medication dosage and depression severity with startle measurements were examined by Spearman's correlation. Male patients with depression, but not euthymic male patients, showed significantly lower PPI at a prepulse of 86 dB and 120 ms lead interval than did male controls. More than half of the male patients with depression showed low-PPI. In contrast, PPI in female patients did not differ from that in female controls in either the depressed or euthymic state. Female patients with active psychosis showed significantly lower PPI than those without psychosis. Female patients on typical antipsychotics had significantly lower PPI, than those without such medication. PPI showed a significant positive correlation with lamotrigine dosage in male patients and

Inhibition of amygdaloid dopamine D2 receptors impairs emotional learning measured with fear-potentiated startle.

PubMed

Greba, Q; Gifkins, A; Kokkinidis, L

2001-04-27

Considerable advances have been made in understanding the neurocircuitry underlying the acquisition and expression of Pavlovian conditioned fear responses. Within the complex cellular and molecular processes mediating fearfulness, amygdaloid dopamine (DA), originating from cells in the ventral tegmental area (VTA) of the midbrain, is thought to contribute to fear-motivated responding. Considering that blockade of DA D(2) receptors is a common mechanism of action for antipsychotic agents, we hypothesized that inhibition of D(2) receptors in the amygdala may be involved in the antiparanoid effects of these drugs. To assess the role of amygdaloid DA D(2) receptors in aversive emotionality, the D(2) receptor antagonist raclopride was infused into the amygdala prior to Pavlovian fear conditioning. Potentiated startle was used as a behavioral indicator of fear and anxiety. Classical fear conditioning and acoustic startle testing were conducted in a single session allowing for the concomitant assessment of shock reactivity with startle enhancement. Depending on dose, the results found conditioned fear acquisition and retention to be impaired following administration of raclopride into the amygdala. Additionally, the learning deficit was dissociated from shock detection and from fear expression assessed with the shock sensitization of acoustic startle. These findings further refine the known neural mechanisms of amygdala-based emotional learning and memory and were interpreted to suggest that, along with D(1) receptors, D(2) receptors in the amygdala may mediate the formation and the retention of newly-acquired fear associations.

Effects of combined exposure to pyridostigmine bromide and shaker stress on acoustic startle response, pre-pulse inhibition and open field behavior in mice.

PubMed

Dubovicky, M; Paton, S; Morris, M; Mach, M; Lucot, J B

2007-01-01

The present study investigated the effect of combined exposure of pyridostigmine bromide (PB) and chronic shaker stress on acoustic startle responses (ASR), pre-pulse inhibition (PPI) and open field behavior of adult C57BL/6J mice. PB (10 mg kg(-1) day(-1) for 7 days) or saline was administered subcutaneously using osmotic Alzet minipumps implanted under the skin on the back of the mice. At the same time, the mice were exposed to 7 days of intermittent shaker stress. They were tested for ASR (100 dB and 120 dB stimuli) and PPI (70 dB + 100 dB and 70 dB + 120 dB) in the acoustic startle monitor system. The mice were assessed during the shaker stress on days 2 and 7 and 7, 14, 21 and 28 days after discontinuation of treatment. Separate groups of mice were tested in the open field in 15 min sessions on days 1, 3 and 6 during shaker stress and PB treatment. Exposure of mice to PB resulted in an exaggerated ASR, reduced PPI and non-significant decrease in locomotor activity. These behavioral changes were apparent only during exposure to PB. Repeated shaker stress did not have any effect on sensorimotor functions or open field behavior of mice. There was no prolonged or delayed effect of PB and/or stress on individual behavioral variables. The study found C57BL/6J mice to be behaviorally sensitive to PB treatment. (c) 2007 John Wiley & Sons, Ltd.

Large-amplitude acoustic solitary waves in a Yukawa chain

NASA Astrophysics Data System (ADS)

Sheridan, T. E.; Gallagher, James C.

2017-06-01

We experimentally study the excitation and propagation of acoustic solitary waves in a one-dimensional dusty plasma (i.e. a Yukawa chain) with particles interacting through a screened Coulomb potential. The lattice constant mm. Waves are launched by applying a 100 mW laser pulse to one end of the chain for laser pulse durations from 0.10 to 2.0 s. We observe damped solitary waves which propagate for distances with an acoustic speed s=11.5\\pm 0.2~\\text{mm}~\\text{s}-1$ . The maximum velocity perturbation increases with laser pulse duration for durations s and then saturates at . The wave speed is found to be independent of the maximum amplitude, indicating that the formation of nonlinear solitons is prevented by neutral-gas damping.

Acoustic-Emergent Phonology in the Amplitude Envelope of Child-Directed Speech

PubMed Central

Leong, Victoria; Goswami, Usha

2015-01-01

When acquiring language, young children may use acoustic spectro-temporal patterns in speech to derive phonological units in spoken language (e.g., prosodic stress patterns, syllables, phonemes). Children appear to learn acoustic-phonological mappings rapidly, without direct instruction, yet the underlying developmental mechanisms remain unclear. Across different languages, a relationship between amplitude envelope sensitivity and phonological development has been found, suggesting that children may make use of amplitude modulation (AM) patterns within the envelope to develop a phonological system. Here we present the Spectral Amplitude Modulation Phase Hierarchy (S-AMPH) model, a set of algorithms for deriving the dominant AM patterns in child-directed speech (CDS). Using Principal Components Analysis, we show that rhythmic CDS contains an AM hierarchy comprising 3 core modulation timescales. These timescales correspond to key phonological units: prosodic stress (Stress AM, ~2 Hz), syllables (Syllable AM, ~5 Hz) and onset-rime units (Phoneme AM, ~20 Hz). We argue that these AM patterns could in principle be used by naïve listeners to compute acoustic-phonological mappings without lexical knowledge. We then demonstrate that the modulation statistics within this AM hierarchy indeed parse the speech signal into a primitive hierarchically-organised phonological system comprising stress feet (proto-words), syllables and onset-rime units. We apply the S-AMPH model to two other CDS corpora, one spontaneous and one deliberately-timed. The model accurately identified 72–82% (freely-read CDS) and 90–98% (rhythmically-regular CDS) stress patterns, syllables and onset-rime units. This in-principle demonstration that primitive phonology can be extracted from speech AMs is termed Acoustic-Emergent Phonology (AEP) theory. AEP theory provides a set of methods for examining how early phonological development is shaped by the temporal modulation structure of speech across

Acoustic-Emergent Phonology in the Amplitude Envelope of Child-Directed Speech.

PubMed

Leong, Victoria; Goswami, Usha

2015-01-01

When acquiring language, young children may use acoustic spectro-temporal patterns in speech to derive phonological units in spoken language (e.g., prosodic stress patterns, syllables, phonemes). Children appear to learn acoustic-phonological mappings rapidly, without direct instruction, yet the underlying developmental mechanisms remain unclear. Across different languages, a relationship between amplitude envelope sensitivity and phonological development has been found, suggesting that children may make use of amplitude modulation (AM) patterns within the envelope to develop a phonological system. Here we present the Spectral Amplitude Modulation Phase Hierarchy (S-AMPH) model, a set of algorithms for deriving the dominant AM patterns in child-directed speech (CDS). Using Principal Components Analysis, we show that rhythmic CDS contains an AM hierarchy comprising 3 core modulation timescales. These timescales correspond to key phonological units: prosodic stress (Stress AM, ~2 Hz), syllables (Syllable AM, ~5 Hz) and onset-rime units (Phoneme AM, ~20 Hz). We argue that these AM patterns could in principle be used by naïve listeners to compute acoustic-phonological mappings without lexical knowledge. We then demonstrate that the modulation statistics within this AM hierarchy indeed parse the speech signal into a primitive hierarchically-organised phonological system comprising stress feet (proto-words), syllables and onset-rime units. We apply the S-AMPH model to two other CDS corpora, one spontaneous and one deliberately-timed. The model accurately identified 72-82% (freely-read CDS) and 90-98% (rhythmically-regular CDS) stress patterns, syllables and onset-rime units. This in-principle demonstration that primitive phonology can be extracted from speech AMs is termed Acoustic-Emergent Phonology (AEP) theory. AEP theory provides a set of methods for examining how early phonological development is shaped by the temporal modulation structure of speech across

Small-amplitude acoustics in bulk granular media

NASA Astrophysics Data System (ADS)

Henann, David L.; Valenza, John J., II; Johnson, David L.; Kamrin, Ken

2013-10-01

We propose and validate a three-dimensional continuum modeling approach that predicts small-amplitude acoustic behavior of dense-packed granular media. The model is obtained through a joint experimental and finite-element study focused on the benchmark example of a vibrated container of grains. Using a three-parameter linear viscoelastic constitutive relation, our continuum model is shown to quantitatively predict the effective mass spectra in this geometry, even as geometric parameters for the environment are varied. Further, the model's predictions for the surface displacement field are validated mode-by-mode against experiment. A primary observation is the importance of the boundary condition between grains and the quasirigid walls.

Effect of combined opioid receptor and α2-adrenoceptor blockade on anxiety and electrically evoked startle responses.

PubMed

Vo, Lechi; Drummond, Peter D

2017-06-01

The R3 component of the electrically evoked blink reflex may form part of a startle reaction. Acoustic startle responses are augmented by yohimbine, an α 2 -adrenoceptor antagonist that blocks α 2 -autoreceptors, and are potentiated by opioid receptor blockade. To investigate these influences on electrically evoked startle responses, 16 mg yohimbine, with (16 participants) or without 50 mg naltrexone (23 participants), was administered in separate double-blind placebo-controlled cross-over experiments. In each experiment, R3 (a probable component of the startle response) was examined before and after high-frequency electrical stimulation of the forearm, a procedure that initiates inhibitory pain controls. Anxiety and somatic symptoms were greater after yohimbine than placebo, and were potentiated by naltrexone. Pain ratings for the electrically evoked startle stimuli decreased after high-frequency electrical stimulation in the placebo session but remained stable after drug administration. Yohimbine with naltrexone, but not yohimbine alone, also blocked an inhibitory effect of high-frequency electrical stimulation on electrically evoked sharp sensations and R3. Together, the findings suggest that adding naltrexone to yohimbine potentiated anxiety and blocked inhibitory influences of high-frequency electrical stimulation on electrically evoked sensations and startle responses. Thus, opioid peptides could reduce activity in nociceptive and startle-reflex pathways, or inhibit crosstalk between these pathways. Failure of this inhibitory opioid influence might be important in chronically painful conditions that are aggravated by startle stimuli.

Sexual orientation-related differences in prepulse inhibition of the human startle response.

PubMed

Rahman, Qazi; Kumari, Veena; Wilson, Glenn D

2003-10-01

Prepulse inhibition (PPI) refers to a reduction in the startle response to a strong sensory stimulus when this stimulus is preceded by a weaker stimulus--the prepulse. PPI reflects a nonlearned sensorimotor gating mechanism and also shows a robust gender difference, with women exhibiting lower PPI than men. The present study examined the eyeblink startle responses to acoustic stimuli of 59 healthy heterosexual and homosexual men and women. Homosexual women showed significantly masculinized PPI compared with heterosexual women, whereas no difference was observed in PPI between homosexual and heterosexual men. These data provide the first evidence for within-gender differences in basic sensorimotor gating mechanisms and implicate the known neural substrates of PPI in human sexual orientation. (c) 2003 APA, all rights reserved

A Finite Difference Numerical Model for the Propagation of Finite Amplitude Acoustical Blast Waves Outdoors Over Hard and Porous Surfaces

DTIC Science & Technology

1991-09-01

Difference Numerical Model for the Propagation of Finite Amplitude Acoustical Blast Waves Outdoors Over Hard and Porous Surfaces by Victor W. Sparrow...The nonlinear acoustic propagation effects require a numerical solution in the time domain. To model a porous ground surface, which in the frequency...incident on the hard and porous surfaces were produced. The model predicted that near grazing finite amplitude acoustic blast waves decay with distance

The cost of assuming the life history of a host: acoustic startle in the parasitoid fly Ormia ochracea

PubMed Central

Rosen, M. J.; Levin, E. C.; Hoy, R. R.

2009-01-01

In the obligatory reproductive dependence of a parasite on its host, the parasite must trade the benefit of ‘outsourcing’ functions like reproduction for the risk of assuming hazards associated with the host. In the present study, we report behavioral adaptations of a parasitic fly, Ormia ochracea, that resemble those of its cricket hosts. Ormia females home in on the male cricket's songs and deposit larvae, which burrow into the cricket, feed and emerge to pupate. Because male crickets call at night, gravid female Ormia in search of hosts are subject to bat predation, in much the same way as female crickets are when responding to male song. We show that Ormia has evolved the same evasive behavior as have crickets: an acoustic startle response to bat-like ultrasound that manifests clearly only during flight. Furthermore, like crickets, Ormia has a sharp response boundary between the frequencies of song and bat cries, resembling categorical perception first described in the context of human speech. PMID:19946084

The cost of assuming the life history of a host: acoustic startle in the parasitoid fly Ormia ochracea.

PubMed

Rosen, M J; Levin, E C; Hoy, R R

2009-12-01

In the obligatory reproductive dependence of a parasite on its host, the parasite must trade the benefit of 'outsourcing' functions like reproduction for the risk of assuming hazards associated with the host. In the present study, we report behavioral adaptations of a parasitic fly, Ormia ochracea, that resemble those of its cricket hosts. Ormia females home in on the male cricket's songs and deposit larvae, which burrow into the cricket, feed and emerge to pupate. Because male crickets call at night, gravid female Ormia in search of hosts are subject to bat predation, in much the same way as female crickets are when responding to male song. We show that Ormia has evolved the same evasive behavior as have crickets: an acoustic startle response to bat-like ultrasound that manifests clearly only during flight. Furthermore, like crickets, Ormia has a sharp response boundary between the frequencies of song and bat cries, resembling categorical perception first described in the context of human speech.

Investigation of the effects of head irradiation with gamma rays and protons on startle and pre-pulse inhibition behavior in mice.

PubMed

Haerich, Paul; Eggers, Cara; Pecaut, Michael J

2012-05-01

With the increased international emphasis on manned space exploration, there is a growing need to understand the impact of the spaceflight environment on health and behavior. One particularly important aspect of this environment is low-dose radiation. In the present studies, we first characterized the γ- and proton-irradiation dose effect on acoustic startle and pre-pulse inhibition behaviors in mice exposed to 0-5 Gy brain-localized irradiation, and assessed these effects 2 days later. Subsequently, we used 2 Gy to assess the time course of γ- and proton-radiation effects on startle reactivity 0-8 days after exposure. Exposures targeted the brain to minimize the impact of peripheral inflammation-induced sickness behavior. The effects of radiation on startle were subtle and acute. Radiation reduced the startle response at 2 and 5 Gy. Following a 2-Gy exposure, the response reached a minimum at the 2-day point. Proton and γ-ray exposures did not differ in their impact on startle. We found there were no effects of radiation on pre-pulse inhibition of the startle response.

The CRH1 antagonist GSK561679 increases human fear but not anxiety as assessed by startle.

PubMed

Grillon, Christian; Hale, Elizabeth; Lieberman, Lynne; Davis, Andrew; Pine, Daniel S; Ernst, Monique

2015-03-13

Fear to predictable threat and anxiety to unpredictable threat reflect distinct processes mediated by different brain structures, the central nucleus of the amygdala and the bed nucleus of the stria terminalis (BNST), respectively. This study tested the hypothesis that the corticotropin-releasing factor (CRF1) antagonist GSK561679 differentially reduces anxiety but increases fear in humans. A total of 31 healthy females received each of four treatments: placebo, 50 mg GSK561679 (low-GSK), 400 mg GSK561679 (high-GSK), and 1 mg alprazolam in a crossover design. Participants were exposed to three conditions during each of the four treatments. The three conditions included one in which predictable aversive shocks were signaled by a cue, a second during which shocks were administered unpredictably, and a third condition without shock. Fear and anxiety were assessed using the acoustic startle reflex. High-GSK had no effect on startle potentiation during unpredictable threat (anxiety) but increased startle potentiation during the predictable condition (fear). Low-GSK did not affect startle potentiation across conditions. Consistent with previous findings, alprazolam reduced startle potentiation during unpredictable threat but not during predictable threat. The increased fear by high-GSK replicates animal findings and suggests a lift of the inhibitory effect of the BNST on the amygdala by the CRF1 antagonist.

Recovery of motor performance following startle.

DOT National Transportation Integrated Search

1969-10-01

Sudden, high-intensity sounds, such as those produced by sonic booms, can be quite startling. Although many studies have investigated physiological response to startle, much less is known concerning the effects of startle on performance. The present ...

SALICYLATE INCREASES THE GAIN OF THE CENTRAL AUDITORY SYSTEM

PubMed Central

Sun, W.; Lu, J.; Stolzberg, D.; Gray, L.; Deng, A.; Lobarinas, E.; Salvi, R. J.

2009-01-01

High doses of salicylate, the anti-inflammatory component of aspirin, induce transient tinnitus and hearing loss. Systemic injection of 250 mg/kg of salicylate, a dose that reliably induces tinnitus in rats, significantly reduced the sound evoked output of the rat cochlea. Paradoxically, salicylate significantly increased the amplitude of the sound-evoked field potential from the auditory cortex (AC) of conscious rats, but not the inferior colliculus (IC). When rats were anesthetized with isoflurane, which increases GABA-mediated inhibition, the salicylate-induced AC amplitude enhancement was abolished, whereas ketamine, which blocks N-methyl-d-aspartate receptors, further increased the salicylate-induced AC amplitude enhancement. Direct application of salicylate to the cochlea, however, reduced the response amplitude of the cochlea, IC and AC, suggesting the AC amplitude enhancement induced by systemic injection of salicylate does not originate from the cochlea. To identify a behavioral correlate of the salicylate-induced AC enhancement, the acoustic startle response was measured before and after salicylate treatment. Salicylate significantly increased the amplitude of the startle response. Collectively, these results suggest that high doses of salicylate increase the gain of the central auditory system, presumably by down-regulating GABA-mediated inhibition, leading to an exaggerated acoustic startle response. The enhanced startle response may be the behavioral correlate of hyperacusis that often accompanies tinnitus and hearing loss. Published by Elsevier Ltd on behalf of IBRO. PMID:19154777

Startling sweet temptations: hedonic chocolate deprivation modulates experience, eating behavior, and eyeblink startle.

PubMed

Blechert, Jens; Naumann, Eva; Schmitz, Julian; Herbert, Beate M; Tuschen-Caffier, Brunna

2014-01-01

Many individuals restrict their food intake to prevent weight gain. This restriction has both homeostatic and hedonic effects but their relative contribution is currently unclear. To isolate hedonic effects of food restriction, we exposed regular chocolate eaters to one week of chocolate deprivation but otherwise regular eating. Before and after this hedonic deprivation, participants viewed images of chocolate and images of high-calorie but non-chocolate containing foods, while experiential, behavioral and eyeblink startle responses were measured. Compared to satiety, hedonic deprivation triggered increased chocolate wanting, liking, and chocolate consumption but also feelings of frustration and startle potentiation during the intertrial intervals. Deprivation was further characterized by startle inhibition during both chocolate and food images relative to the intertrial intervals. Individuals who responded with frustration to the manipulation and those who scored high on a questionnaire of impulsivity showed more relative startle inhibition. The results reveal the profound effects of hedonic deprivation on experiential, behavioral and attentional/appetitive response systems and underscore the role of individual differences and state variables for startle modulation. Implications for dieting research and practice as well as for eating and weight disorders are discussed.

Startling Sweet Temptations: Hedonic Chocolate Deprivation Modulates Experience, Eating Behavior, and Eyeblink Startle

PubMed Central

Blechert, Jens; Naumann, Eva; Schmitz, Julian; Herbert, Beate M.; Tuschen-Caffier, Brunna

2014-01-01

Many individuals restrict their food intake to prevent weight gain. This restriction has both homeostatic and hedonic effects but their relative contribution is currently unclear. To isolate hedonic effects of food restriction, we exposed regular chocolate eaters to one week of chocolate deprivation but otherwise regular eating. Before and after this hedonic deprivation, participants viewed images of chocolate and images of high-calorie but non-chocolate containing foods, while experiential, behavioral and eyeblink startle responses were measured. Compared to satiety, hedonic deprivation triggered increased chocolate wanting, liking, and chocolate consumption but also feelings of frustration and startle potentiation during the intertrial intervals. Deprivation was further characterized by startle inhibition during both chocolate and food images relative to the intertrial intervals. Individuals who responded with frustration to the manipulation and those who scored high on a questionnaire of impulsivity showed more relative startle inhibition. The results reveal the profound effects of hedonic deprivation on experiential, behavioral and attentional/appetitive response systems and underscore the role of individual differences and state variables for startle modulation. Implications for dieting research and practice as well as for eating and weight disorders are discussed. PMID:24416437

Differential startle magnitude in mice selected for high and low swim analgesia is not related to difference in nociception.

PubMed

Blaszczyk, Janusz W; Lapo, Iwona B; Werka, Tomasz; Sadowski, Bogdan

2010-01-01

The acoustic startle response (ASR) elicited by 110 dB 10-ms pulses was studied in relation to pain sensitivity in mouse lines selectively bred for high (HA) and for low (LA) swim analgesia. The magnitudes of ASR, similarly as hot-plate latencies, differed between the lines in the rank order HA is greater than unselected controls (C) greater than LA. The animals' nociception did not change after the ASR session consisting of a sequence of 20 acoustic stimuli. Morphine hydrochloride (5 and 10 mg per kg i.p.) increased hot-plate latencies in the order of HA greater than C greater than LA, and was not effective on ASR magnitude in HA as well as in C mice. In the LA line, 10 mg per kg of morphine slightly attenuated ASR, but caused only a little analgesia. We conclude that (1) the difference in ASR between the selected lines is inversely correlated with the difference in pain sensitivity; (2) the magnitude of ASR is not altered by morphine analgesia; (3) the procedure of ASR using brief acoustic pulses is not stressful enough to elicit a form of stress analgesia. The lack of a direct relationship between the readiness to startle and pain sensation may be beneficial for an animal's survival in dangerous situations. It is beneficial when the startle to a warning signal precedes defensive behaviors and it often must be effectuated in a state of decreased nociception.

Acute Hydrocortisone Treatment Increases Anxiety but Not Fear in Healthy Volunteers: A Fear-Potentiated Startle Study

PubMed Central

Grillon, Christian; Heller, Randi; Hirschhorn, Elizabeth; Kling, Mitchel A.; Pine, Daniel S.; Schulkin, Jay; Vythilingam, Meena

2011-01-01

Background The debilitating effects of chronic glucocorticoids excess are well-known, but comparatively little is understood about the role of acute cortisol. Indirect evidence in rodents suggests that acute cortisone could selectively increase some forms of long-duration aversive states, such as “anxiety,” but not relatively similar, briefer aversive states, such as “fear.” However, no prior experimental studies in humans consider the unique effects of cortisol on anxiety and fear, using well-validated methods for eliciting these two similar but dissociable aversive states. The current study examines these effects, as instantiated with short- and long-duration threats. Methods Healthy volunteers (n = 18) received placebo or a low (20 mg) or a high (60 mg) dose of hydrocortisone in a double-blind crossover design. Subjects were exposed repeatedly to three 150-sec duration conditions: no shock; predictable shocks, in which shocks were signaled by a short-duration threat cue; and unpredictable shocks. Aversive states were indexed by acoustic startle. Fear was operationally defined as the increase in startle reactivity during the threat cue in the predictable condition (fear-potentiated startle). Anxiety was operationally defined as the increase in baseline startle from the no shock to the two threat conditions (anxiety-potentiated startle). Results Hydrocortisone affected neither baseline nor short-duration, fear-potentiated startle but increased long-duration anxiety-potentiated startle. Conclusions These results suggest that hydrocortisone administration in humans selectively increases anxiety but not fear. Possible mechanisms implicated are discussed in light of prior data in rodents. Specifically, hydrocortisone might increase anxiety via sensitization of corticotrophin-releasing hormones in the bed nucleus of the stria terminalis. PMID:21277566

Existence domains of arbitrary amplitude nonlinear structures in two-electron temperature space plasmas. II. High-frequency electron-acoustic solitons

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maharaj, S. K.; Bharuthram, R.; Singh, S. V.

2012-12-15

A three-component plasma model composed of ions, cool electrons, and hot electrons is adopted to investigate the existence of large amplitude electron-acoustic solitons not only for the model for which inertia and pressure are retained for all plasma species which are assumed to be adiabatic but also neglecting inertial effects of the hot electrons. Using the Sagdeev potential formalism, the Mach number ranges supporting the existence of large amplitude electron-acoustic solitons are presented. The limitations on the attainable amplitudes of electron-acoustic solitons having negative potentials are attributed to a number of different physical reasons, such as the number density ofmore » either the cool electrons or hot electrons ceases to be real valued beyond the upper Mach number limit, or, alternatively, a negative potential double layer occurs. Electron-acoustic solitons having positive potentials are found to be supported only if inertial effects of the hot electrons are retained and these are found to be limited only by positive potential double layers.« less

The CRH1 Antagonist GSK561679 Increases Human Fear But Not Anxiety as Assessed by Startle

PubMed Central

Grillon, Christian; Hale, Elizabeth; Lieberman, Lynne; Davis, Andrew; Pine, Daniel S; Ernst, Monique

2015-01-01

Fear to predictable threat and anxiety to unpredictable threat reflect distinct processes mediated by different brain structures, the central nucleus of the amygdala and the bed nucleus of the stria terminalis (BNST), respectively. This study tested the hypothesis that the corticotropin-releasing factor (CRF1) antagonist GSK561679 differentially reduces anxiety but increases fear in humans. A total of 31 healthy females received each of four treatments: placebo, 50 mg GSK561679 (low-GSK), 400 mg GSK561679 (high-GSK), and 1 mg alprazolam in a crossover design. Participants were exposed to three conditions during each of the four treatments. The three conditions included one in which predictable aversive shocks were signaled by a cue, a second during which shocks were administered unpredictably, and a third condition without shock. Fear and anxiety were assessed using the acoustic startle reflex. High-GSK had no effect on startle potentiation during unpredictable threat (anxiety) but increased startle potentiation during the predictable condition (fear). Low-GSK did not affect startle potentiation across conditions. Consistent with previous findings, alprazolam reduced startle potentiation during unpredictable threat but not during predictable threat. The increased fear by high-GSK replicates animal findings and suggests a lift of the inhibitory effect of the BNST on the amygdala by the CRF1 antagonist. PMID:25430779

Interactions of Stress and Nicotine on Amplitude, Pre-Pulse Inhibition and Habituation of the Acoustic Startle Reflex

DTIC Science & Technology

1992-09-24

Marquez , Armario , & Gelpi, 1988) consistent with a stress response . Restraint stress has been reported to increase the amplitude of sensory...and NE in the brain (Adell , Garcia- Marquez , Armario , & Gelpi , 1988) consistent with a stress response. Restraint stress has been reported t o...and non- reactive strains. Al coholism. Clinical and Experimental Research, ~(2), 170-174. Adell, A., Garcia - Marquez, C., Armario , A. , & Gelpi , E

Corticotropin-releasing factor (CRF) and α 2 adrenergic receptors mediate heroin withdrawal-potentiated startle in rats.

PubMed

Park, Paula E; Vendruscolo, Leandro F; Schlosburg, Joel E; Edwards, Scott; Schulteis, Gery; Koob, George F

2013-09-01

Anxiety is one of the early symptoms of opioid withdrawal and contributes to continued drug use and relapse. The acoustic startle response (ASR) is a component of anxiety that has been shown to increase during opioid withdrawal in both humans and animals. We investigated the role of corticotropin-releasing factor (CRF) and norepinephrine (NE), two key mediators of the brain stress system, on acute heroin withdrawal-potentiated ASR. Rats injected with heroin (2 mg/kg s.c.) displayed an increased ASR when tested 4 h after heroin treatment. A similar increase in ASR was found in rats 10-20 h into withdrawal from extended access (12 h) to i.v. heroin self-administration, a model that captures several aspects of heroin addiction in humans. Both the α 2 adrenergic receptor agonist clonidine (10 μg/kg s.c.) and CRF1 receptor antagonist N,N-bis(2-methoxyethyl)-3-(4-methoxy-2-methylphenyl)-2,5-dimethyl-pyrazolo[1,5-a] pyrimidin-7-amine (MPZP; 20 mg/kg s.c.) blocked heroin withdrawal-potentiated startle. To investigate the relationship between CRF1 and α 2 adrenergic receptors in the potentiation of the ASR, we tested the effect of MPZP on yohimbine (1.25 mg/kg s.c.)-potentiated startle and clonidine on CRF (2 μg i.c.v.)-potentiated startle. Clonidine blocked CRF-potentiated startle, whereas MPZP partially attenuated but did not reverse yohimbine-potentiated startle, suggesting that CRF may drive NE release to potentiate startle. These results suggest that CRF1 and α 2 receptors play an important role in the heightened anxiety-like behaviour observed during acute withdrawal from heroin, possibly via CRF inducing the release of NE in stress-related brain regions.

On measurement of the acoustic nonlinearity parameter using the finite amplitude insertion substitution (FAIS) technique

NASA Astrophysics Data System (ADS)

Zeqiri, Bajram; Cook, Ashley; Rétat, Lise; Civale, John; ter Haar, Gail

2015-04-01

The acoustic nonlinearity parameter, B/A, is an important parameter which defines the way a propagating finite amplitude acoustic wave progressively distorts when travelling through any medium. One measurement technique used to determine its value is the finite amplitude insertion substitution (FAIS) method which has been applied to a range of liquid, tissue and tissue-like media. Importantly, in terms of the achievable measurement uncertainties, it is a relative technique. This paper presents a detailed study of the method, employing a number of novel features. The first of these is the use of a large area membrane hydrophone (30 mm aperture) which is used to record the plane-wave component of the acoustic field. This reduces the influence of diffraction on measurements, enabling studies to be carried out within the transducer near-field, with the interrogating transducer, test cell and detector positioned close to one another, an attribute which assists in controlling errors arising from nonlinear distortion in any intervening water path. The second feature is the development of a model which estimates the influence of finite-amplitude distortion as the acoustic wave travels from the rear surface of the test cell to the detector. It is demonstrated that this can lead to a significant systematic error in B/A measurement whose magnitude and direction depends on the acoustic property contrast between the test material and the water-filled equivalent cell. Good qualitative agreement between the model and experiment is reported. B/A measurements are reported undertaken at (20 ± 0.5) °C for two fluids commonly employed as reference materials within the technical literature: Corn Oil and Ethylene Glycol. Samples of an IEC standardised agar-based tissue-mimicking material were also measured. A systematic assessment of measurement uncertainties is presented giving expanded uncertainties in the range ±7% to ±14%, expressed at a confidence level close to 95

Enhanced startle reflexivity during presentation of visual nurture cues in young adults who experienced parental divorce in early childhood.

PubMed

Hengesch, Xenia; Larra, Mauro F; Finke, Johannes B; Blumenthal, Terry D; Schächinger, Hartmut

2017-10-01

Adverse childhood experiences (ACE) may influence stress and affective processing in adulthood. Animal and human studies show enhanced startle reflexivity in adult participants with ACE. This study examined the impact of one of the most common ACE, parental divorce, on startle reflexivity in adulthood. Affective modulation of acoustically-elicited startle eye blink was assessed in a group of 23 young adults with self-reported history of parental divorce, compared to an age- and sex-matched control group (n=18). Foreground pictures were either aversive (e.g. mutilation and injury), standard appetitive (e.g. erotic, recreational sport), or nurture pictures (e.g. related to early life, parental care), intermixed with neutral pictures (e.g. household objects), and organized in three valence blocks delivered in a balanced, pseudo-randomized sequence. During picture viewing startle eye blinks were elicited by binaural white noise bursts (50ms, 105 dB) via headphones and recorded at the left orbicularis oculi muscle via EMG. A significant interaction of group×picture valence (p=0.01) was observed. Contrast with controls revealed blunted startle responsiveness of the ACE group during presentation of aversive pictures, but enhanced startle during presentation of nurture-related pictures. No group differences were found during presentation of standard appetitive pictures. ACE participants rated nurture pictures as more arousing (p=0.02) than did control participants. Results suggest that divorce in childhood led to altered affective context information processing in early adulthood. When exposed to unpleasant (vs. neutral) pictures participants with ACE showed less startle potentiation than controls. Nurture context, however, potentiated startle in ACE participants, suggesting visual cuing to activate protective behavioral responses. Copyright © 2017 Elsevier B.V. All rights reserved.

Effects of smoking on the acoustic startle response and prepulse inhibition in smokers with and without posttraumatic stress disorder.

PubMed

Vrana, Scott R; Calhoun, Patrick S; McClernon, F Joseph; Dennis, Michelle F; Lee, Sherman T; Beckham, Jean C

2013-12-01

Cigarette smokers smoke in part because nicotine helps regulate attention. Prepulse inhibition (PPI) of the startle reflex is a measure of early attentional gating that is reduced in abstinent smokers and in groups with attention regulation difficulties. Attention difficulties are found in people with posttraumatic stress disorder (PTSD). The aim of this study is to assess whether smoking and abstinence differentially affect the startle response and PPI in smokers with and without PTSD. Startle response and PPI (prepulses at 60, 120, or 240 ms) were measured in smokers with (N = 39) and without (N = 61) PTSD, while smoking and again while abstinent. Participants with PTSD produced both larger magnitude and faster latency startle responses than controls. Across groups, PPI was greater when smoking than when abstinent. The PTSD and control group exhibited different patterns of PPI across prepulse intervals when smoking and when abstinent. Older age was associated with reduced PPI, but only when abstinent from smoking. The effects of PTSD on startle magnitude and of smoking on PPI replicate earlier studies. The different pattern of PPI exhibited in PTSD and control groups across prepulse intervals, while smoking and abstinent suggests that previous research on smoking and PPI has been limited by not including longer prepulse intervals, and that nicotine may affect the time course as well as increasing the level of PPI. The reduced PPI among older participants during abstinence suggests that nicotine may play a role in maintaining attention in older smokers, which may motivate continued smoking in older individuals.

Temperature and Pressure Dependence of Signal Amplitudes for Electrostriction Laser-Induced Thermal Acoustics

NASA Technical Reports Server (NTRS)

Herring, Gregory C.

2015-01-01

The relative signal strength of electrostriction-only (no thermal grating) laser-induced thermal acoustics (LITA) in gas-phase air is reported as a function of temperature T and pressure P. Measurements were made in the free stream of a variable Mach number supersonic wind tunnel, where T and P are varied simultaneously as Mach number is varied. Using optical heterodyning, the measured signal amplitude (related to the optical reflectivity of the acoustic grating) was averaged for each of 11 flow conditions and compared to the expected theoretical dependence of a pure-electrostriction LITA process, where the signal is proportional to the square root of [P*P /( T*T*T)].

Planning of Ballistic Movement following Stroke: Insights from the Startle Reflex

PubMed Central

Honeycutt, Claire Fletcher; Perreault, Eric Jon

2012-01-01

Following stroke, reaching movements are slow, segmented, and variable. It is unclear if these deficits result from a poorly constructed movement plan or an inability to voluntarily execute an appropriate plan. The acoustic startle reflex provides a means to initiate a motor plan involuntarily. In the presence of a movement plan, startling acoustic stimulus triggers non-voluntary early execution of planned movement, a phenomenon known as the startReact response. In unimpaired individuals, the startReact response is identical to a voluntarily initiated movement, except that it is elicited 30–40 ms. As the startReact response is thought to be mediated by brainstem pathways, we hypothesized that the startReact response is intact in stroke subjects. If startReact is intact, it may be possible to elicit more task-appropriate patterns of muscle activation than can be elicited voluntarily. We found that startReact responses were intact following stroke. Responses were initiated as rapidly as those in unimpaired subjects, and with muscle coordination patterns resembling those seen during unimpaired volitional movements. Results were striking for elbow flexion movements, which demonstrated no significant differences between the startReact responses elicited in our stroke and unimpaired subject groups. The results during planned extension movements were less straightforward for stroke subjects, since the startReact response exhibited task inappropriate activity in the flexors. This inappropriate activity diminished over time. This adaptation suggests that the inappropriate activity was transient in nature and not related to the underlying movement plan. We hypothesize that the task-inappropriate flexor activity during extension results from an inability to suppress the classic startle reflex, which primarily influences flexor muscles and adapts rapidly with successive stimuli. These results indicate that stroke subjects are capable of planning ballistic elbow movements

The gap-startle paradigm to assess auditory temporal processing: Bridging animal and human research.

PubMed

Fournier, Philippe; Hébert, Sylvie

2016-05-01

The gap-prepulse inhibition of the acoustic startle (GPIAS) paradigm is the primary test used in animal research to identify gap detection thresholds and impairment. When a silent gap is presented shortly before a loud startling stimulus, the startle reflex is inhibited and the extent of inhibition is assumed to reflect detection. Here, we applied the same paradigm in humans. One hundred and fifty-seven normal-hearing participants were tested using one of five gap durations (5, 25, 50, 100, 200 ms) in one of the following two paradigms-gap-embedded in or gap-following-the continuous background noise. The duration-inhibition relationship was observable for both conditions but followed different patterns. In the gap-embedded paradigm, GPIAS increased significantly with gap duration up to 50 ms and then more slowly up to 200 ms (trend only). In contrast, in the gap-following paradigm, significant inhibition-different from 0--was observable only at gap durations from 50 to 200 ms. The finding that different patterns are found depending on gap position within the background noise is compatible with distinct mechanisms underlying each of the two paradigms. © 2016 Society for Psychophysiological Research.

Effects of periadolescent fluoxetine and paroxetine on elevated plus-maze, acoustic startle, and swimming immobility in rats while on and off-drug.

PubMed

Vorhees, Charles V; Morford, LaRonda R; Graham, Devon L; Skelton, Matthew R; Williams, Michael T

2011-10-05

Whether selective serotonin reuptake inhibitors (SSRIs) exposure during adolescent brain development causes lasting effects remains unresolved. Assess the effects of fluoxetine and paroxetine 60 days after adolescent exposure compared with when on-drug. Male Sprague-Dawley littermates (41 litters) were gavaged on postnatal days 33-53 with fluoxetine (3 or 10 mg/kg/day), paroxetine (3, 10 or, 17 mg/kg/day), or water; half were tested while on-drug (21 litters) and half after 60 days off-drug (20 litters). The highest dose of the drugs reduced body weight gain during treatment that rebounded 1 week post-treatment. On-drug, no significant group differences were found on elevated plus maze time-in-open, zone entries, or latency to first open entry; however, the high dose of paroxetine significantly reduced head-dips (N=20/group). No significant effects were found on-drug for acoustic startle response/prepulse inhibition (ASR/PPI) although a trend (p<0.10) was seen, which after combining dose levels, showed a significant increase in ASR amplitude for both fluoxetine and paroxetine (N=20-21/group). No differences on immobility time were seen in the Porsolt forced swim test or in plasma corticosterone at the end of forced swim (N-19-21/group). Off-drug, no effects were seen in the elevated plus maze (N=16/group), ASR/PPI (N=20/group), forced swim (N=19-20/group), or plasma corticosterone (N=19/group). At the doses tested, fluoxetine and paroxetine induced minor effects with drug on-board but no residual, long-term adverse effects in rats 60 days after drug discontinuation. The data provide no evidence that fluoxetine or paroxetine have long-term adverse effects on the behaviors measured here after adolescent to young adult exposure.

A method for approximating acoustic-field-amplitude uncertainty caused by environmental uncertainties.

PubMed

James, Kevin R; Dowling, David R

2008-09-01

In underwater acoustics, the accuracy of computational field predictions is commonly limited by uncertainty in environmental parameters. An approximate technique for determining the probability density function (PDF) of computed field amplitude, A, from known environmental uncertainties is presented here. The technique can be applied to several, N, uncertain parameters simultaneously, requires N+1 field calculations, and can be used with any acoustic field model. The technique implicitly assumes independent input parameters and is based on finding the optimum spatial shift between field calculations completed at two different values of each uncertain parameter. This shift information is used to convert uncertain-environmental-parameter distributions into PDF(A). The technique's accuracy is good when the shifted fields match well. Its accuracy is evaluated in range-independent underwater sound channels via an L(1) error-norm defined between approximate and numerically converged results for PDF(A). In 50-m- and 100-m-deep sound channels with 0.5% uncertainty in depth (N=1) at frequencies between 100 and 800 Hz, and for ranges from 1 to 8 km, 95% of the approximate field-amplitude distributions generated L(1) values less than 0.52 using only two field calculations. Obtaining comparable accuracy from traditional methods requires of order 10 field calculations and up to 10(N) when N>1.

Methadone patients exhibit increased startle and cortisol response after intravenous yohimbine.

PubMed

Stine, S M; Grillon, C G; Morgan, C A; Kosten, T R; Charney, D S; Krystal, J H

2001-03-01

Brain noradrenergic systems have been shown to be altered in opioid dependence and to mediate aspects of opioid withdrawal. Pre-clinical and clinical studies by others have shown that yohimbine, which increases noradrenergic activity, also increases both baseline and fear enhancement of the magnitude of the acoustic startle response (ASR). In a separate report from this experiment, it was shown that yohimbine produced opioid withdrawal-like symptoms, including anxiety, in clinically stable methadone-maintained patients and also produced elevations in the norepinepherine (NE) metabolite, 3-methoxy-4 hydroxyphenethyleneglycol (MHPG), and cortisol serum levels. The current study reports the effects of intravenous yohimbine hydrochloride, 0.4 mg/kg versus saline (double-blind), on ASR magnitude, plasma MHPG, and cortisol levels in eight methadone-maintained patients and 13 healthy subjects in a double-blind fashion. Yohimbine increased startle magnitude in both groups. There was no basal (placebo day) difference between the startle response of the two groups, but methadone patients had a larger startle magnitude increase in response to yohimbine than healthy controls. Methadone-maintained patients had lower baseline plasma levels of MHPG and similar baseline plasma cortisol levels compared with normal subjects. Yohimbine caused significant elevation in cortisol and MHPG in both groups. Methadone-maintained subjects had higher elevations in cortisol levels and MHPG (methadone main effect) levels in response to yohimbine. However, when MHPG levels were corrected for baseline differences by analysis of covariance (ANCOVA), the yohimbine effect, but not the methadone effect remained statistically significant. These results are consistent with the previous report and support the hypothesis that abnormalities of the hypothalamic-pituitary-adrenal (HPA) axis and of noradrenergic mechanisms of stress response persist in opioid-agonist maintenance. The ASR effect extends the

Behavioral consequences of radiation exposure to simulated space radiation in the C57BL/6 mouse: open field, rotorod, and acoustic startle

NASA Technical Reports Server (NTRS)

Pecaut, Michael J.; Haerich, Paul; Zuccarelli, Cara N.; Smith, Anna L.; Zendejas, Eric D.; Nelson, Gregory A.

2002-01-01

Two experiments were carried out to investigate the consequences of exposure to proton radiation, such as might occur for astronauts during space flight. C57BL/6 mice were exposed, either with or without 15-g/cm2 aluminum shielding, to 0-, 3-, or 4-Gy proton irradiation mimicking features of a solar particle event. Irradiation produced transient direct deficits in open-field exploratory behavior and acoustic startle habituation. Rotorod performance at 18 rpm was impaired by exposure to proton radiation and was impaired at 26 rpm, but only for mice irradiated with shielding and at the 4-Gy dose. Long-term (>2 weeks) indirect deficits in open-field activity appeared as a result of impaired experiential encoding immediately following exposure. A 2-week recovery prior to testing decreased most of the direct effects of exposure, with only rotorod performance at 26 rpm being impaired. These results suggest that the performance deficits may have been mediated by radiation damage to hippocampal, cerebellar, and possibly, forebrain dopaminergic function.

GABAergic Neural Activity Involved in Salicylate-Induced Auditory Cortex Gain Enhancement

PubMed Central

Lu, Jianzhong; Lobarinas, Edward; Deng, Anchun; Goodey, Ronald; Stolzberg, Daniel; Salvi, Richard J.; Sun, Wei

2011-01-01

Although high doses of sodium salicylate impair cochlear function, it paradoxically enhances sound-evoked activity in the auditory cortex (AC) and augments acoustic startle reflex responses, neural and behavioral metrics associated with hyperexcitability and hyperacusis. To explore the neural mechanisms underlying salicylate-induced hyperexcitability and “increased central gain”, we examined the effects of γ-aminobutyric acid (GABA) receptor agonists and antagonists on salicylate-induced hyperexcitability in the AC and startle reflex responses. Consistent with our previous findings, local or systemic application of salicylate significantly increased the amplitude of sound-evoked AC neural activity, but generally reduced spontaneous activity in the AC. Systemic injection of salicylate also significantly increased the acoustic startle reflex. S-baclofen or R-baclofen, GABA-B agonists, which suppressed sound-evoked AC neural firing rate and local field potentials, also suppressed the salicylate-induced enhancement of the AC field potential and the acoustic startle reflex. Local application of vigabatrin, which enhances GABA concentration in the brain, suppressed the salicylate-induced enhancement of AC firing rate. Systemic injection of vigabatrin also reduced the salicylate-induced enhancement of acoustic startle reflex. Collectively, these results suggest that the sound-evoked behavioral and neural hyperactivity induced by salicylate may arise from a salicylate-induced suppression GABAergic inhibition in the AC. PMID:21664433

Motivational priming and processing interrupt: startle reflex modulation during shallow and deep processing of emotional words.

PubMed

Herbert, Cornelia; Kissler, Johanna

2010-05-01

Valence-driven modulation of the startle reflex, that is larger eyeblinks during viewing of unpleasant pictures and inhibited blinks while viewing pleasant pictures, is well documented. The current study investigated, whether this motivational priming pattern also occurs during processing of unpleasant and pleasant words, and to what extent it is influenced by shallow vs. deep encoding of verbal stimuli. Emotional and neutral adjectives were presented for 5s, and the acoustically elicited startle eyeblink response was measured while subjects memorized the words by means of shallow or deep processing strategies. Results showed blink potentiation to unpleasant and blink inhibition to pleasant adjectives in subjects using shallow encoding strategies. In subjects using deep-encoding strategies, blinks were larger for pleasant than unpleasant or neutral adjectives. In line with this, free recall of pleasant words was also better in subjects who engaged in deep processing. The results suggest that motivational priming holds as long as processing is perceptual. However, during deep processing the startle reflex appears to represent a measure of "processing interrupt", facilitating blinks to those stimuli that are more deeply encoded. Copyright 2010 Elsevier B.V. All rights reserved.

Nanoparticle agglomeration in an evaporating levitated droplet for different acoustic amplitudes

NASA Astrophysics Data System (ADS)

Tijerino, Erick; Basu, Saptarshi; Kumar, Ranganathan

2013-01-01

Radiatively heated levitated functional droplets with nanosilica suspensions exhibit three distinct stages namely pure evaporation, agglomeration, and finally structure formation. The temporal history of the droplet surface temperature shows two inflection points. One inflection point corresponds to a local maximum and demarcates the end of transient heating of the droplet and domination of vaporization. The second inflection point is a local minimum and indicates slowing down of the evaporation rate due to surface accumulation of nanoparticles. Morphology and final precipitation structures of levitated droplets are due to competing mechanisms of particle agglomeration, evaporation, and shape deformation. In this work, we provide a detailed analysis for each process and propose two important timescales for evaporation and agglomeration that determine the final diameter of the structure formed. It is seen that both agglomeration and evaporation timescales are similar functions of acoustic amplitude (sound pressure level), droplet size, viscosity, and density. However, we show that while the agglomeration timescale decreases with initial particle concentration, the evaporation timescale shows the opposite trend. The final normalized diameter can be shown to be dependent solely on the ratio of agglomeration to evaporation timescales for all concentrations and acoustic amplitudes. The structures also exhibit various aspect ratios (bowls, rings, spheroids) which depend on the ratio of the deformation timescale (tdef) and the agglomeration timescale (tg). For tdef

Nonlinear Excitation of Acoustic Modes by Large Amplitude Alfvén waves in the Large Plasma Device (LAPD)

NASA Astrophysics Data System (ADS)

Dorfman, S. E.; Carter, T. A.; Pribyl, P.; Tripathi, S.; Van Compernolle, B.; Vincena, S. T.; Sydora, R. D.

2013-12-01

Alfvén waves, a fundamental mode of magnetized plasmas, are ubiquitous in space plasmas. While the linear behavior of these waves has been extensively studied [1], non-linear effects are important in many real systems, including the solar corona and solar wind. In particular, a parametric decay process in which a large amplitude Alfvén wave decays into an ion acoustic wave and backward propagating Alfvén wave may play an important role in the coronal heating problem. Specifically, the decay of large-amplitude Alfvén waves propagating outward from the photosphere could lead to heating of the corona by the daughter ion acoustic modes [2]. As direct observational evidence of parametric decay is limited [3], laboratory experiments may play an important role in validating simple theoretical predictions and aiding in the interpretation of space measurements. Recent counter-propagating Alfvén wave experiments in the Large Plasma Device (LAPD) have recorded the first laboratory observation of the Alfvén-acoustic mode coupling at the heart of this parametric decay instability [4]. A resonance in the beat wave response produced by the two launched Alfvén waves is observed and is identified as a damped ion acoustic mode based on the measured dispersion relation. Other properties of the interaction including the spatial profile of the beat mode and response amplitude are also consistent with theoretical predictions for a three-wave interaction driven by a nonlinear ponderomotive force. Strong damping observed after the pump Alfvén waves are turned off is under investigation; a novel ion acoustic wave launcher is under development to launch the mode directly for damping studies. New experiments also aim to identify decay instabilities from a single large-amplitude Alfvén wave. In conjunction with these experiments, gyrokinetic simulation efforts are underway to scope out the relevant parameter space. [1] W. Gekelman, et. al., Phys. Plasmas 18, 055501 (2011). [2] F

Emotion dysregulation in alexithymia: Startle reactivity to fearful affective imagery and its relation to heart rate variability.

PubMed

Panayiotou, Georgia; Constantinou, Elena

2017-09-01

Alexithymia is associated with deficiencies in recognizing and expressing emotions and impaired emotion regulation, though few studies have verified the latter assertion using objective measures. This study examined startle reflex modulation by fearful imagery and its associations with heart rate variability in alexithymia. Fifty-four adults (27 alexithymic) imagined previously normed fear scripts. Startle responses were assessed during baseline, first exposure, and reexposure. During first exposure, participants, in separate trials, engaged in either shallow or deep emotion processing, giving emphasis on descriptive or affective aspects of imagery, respectively. Resting heart rate variability was assessed during 2 min of rest prior to the experiment, with high alexithymic participants demonstrating significantly higher LF/HF (low frequency/high frequency) ratio than controls. Deep processing was associated with nonsignificantly larger and faster startle responses at first exposure for alexithymic participants. Lower LF/HF ratio, reflecting higher parasympathetic cardiac activity, predicted greater startle amplitude habituation for alexithymia but lower habituation for controls. Results suggest that, when exposed to prolonged threat, alexithymics may adjust poorly, showing a smaller initial defensive response but slower habituation. This pattern seems related to their low emotion regulation ability as indexed by heart rate variability. © 2017 Society for Psychophysiological Research.

Effect of electron temperature on small-amplitude electron acoustic solitary waves in non-planar geometry

NASA Astrophysics Data System (ADS)

Bansal, Sona; Aggarwal, Munish; Gill, Tarsem Singh

2018-04-01

Effects of electron temperature on the propagation of electron acoustic solitary waves in plasma with stationary ions, cold and superthermal hot electrons is investigated in non-planar geometry employing reductive perturbation method. Modified Korteweg-de Vries equation is derived in the small amplitude approximation limit. The analytical and numerical calculations of the KdV equation reveal that the phase velocity of the electron acoustic waves increases as one goes from planar to non planar geometry. It is shown that the electron temperature ratio changes the width and amplitude of the solitary waves and when electron temperature is not taken into account,our results completely agree with the results of Javidan & Pakzad (2012). It is found that at small values of τ , solitary wave structures behave differently in cylindrical ( {m} = 1), spherical ( {m} = 2) and planar geometry ( {m} = 0) but looks similar at large values of τ . These results may be useful to understand the solitary wave characteristics in laboratory and space environments where the plasma have multiple temperature electrons.

Effect of facial self-resemblance on the startle response and subjective ratings of erotic stimuli in heterosexual men.

PubMed

Lass-Hennemann, Johanna; Deuter, Christian E; Kuehl, Linn K; Schulz, Andre; Blumenthal, Terry D; Schachinger, Hartmut

2011-10-01

Cues of kinship are predicted to increase prosocial behavior due to the benefits of inclusive fitness, but to decrease approach motivation due to the potential costs of inbreeding. Previous studies have shown that facial resemblance, a putative cue of kinship, increases prosocial behavior. However, the effects of facial resemblance on mating preferences are equivocal, with some studies finding that facial resemblance decreases sexual attractiveness ratings, while other studies show that individuals choose mates partly on the basis of similarity. To further investigate this issue, a psychophysiological measure of affective processing, the startle response, was used in this study, assuming that differences in approach motivation to erotic pictures will modulate startle. Male volunteers (n = 30) viewed 30 pictures of erotic female nudes while startle eyeblink responses were elicited by acoustic noise probes. The female nude pictures were digitally altered so that the face either resembled the male participant or another participant, or were not altered. Non-nude neutral pictures were also included. Importantly, the digital alteration was undetected by the participants. Erotic pictures were rated as being pleasant and clearly reduced startle eyeblink magnitude as compared to neutral pictures. Participants showed greater startle inhibition to self-resembling than to other-resembling or non-manipulated female nude pictures, but subjective pleasure and arousal ratings did not differ among the three erotic picture categories. Our data suggest that visual facial resemblance of opposite-sex nudes increases approach motivation in men, and that this effect was not due to their conscious evaluation of the erotic stimuli.

Startle stimuli reduce the internal model control in discrete movements.

PubMed

Wright, Zachary A; Rogers, Mark W; MacKinnon, Colum D; Patton, James L

2009-01-01

A well known and major component of movement control is the feedforward component, also known as the internal model. This model predicts and compensates for expected forces seen during a movement, based on recent experience, so that a well-learned task such as reaching to a target can be executed in a smooth straight manner. It has recently been shown that the state of preparation of planned movements can be tested using a startling acoustic stimulus (SAS). SAS, presented 500, 250 or 0 ms before the expected "go" cue resulted in the early release of the movement trajectory associated with the after-effects of the force field training (i.e. the internal model). In a typical motor adaptation experiment with a robot-applied force field, we tested if a SAS stimulus influences the size of after-effects that are typically seen. We found that in all subjects the after-effect magnitudes were significantly reduced when movements were released by SAS, although this effect was not further modulated by the timing of SAS. Reduced after-effects reveal at least partial existence of learned preparatory control, and identify startle effects that could influence performance in tasks such as piloting, teleoperation, and sports.

Testing neurophysiological markers related to fear-potentiated startle.

PubMed

Seligowski, Antonia V; Bondy, Erin; Singleton, Paris; Orcutt, Holly K; Ressler, Kerry J; Auerbach, Randy P

2018-06-11

Fear-potentiated startle (FPS) paradigms provide insight into fear learning mechanisms that contribute to impairment among individuals with posttraumatic stress symptoms (PTSS). Electrophysiology also has provided insight into these mechanisms through the examination of event-related potentials (ERPs) such as the P100 and LPP. It remains unclear, however, whether the P100 and LPP may be related to fear learning processes within the FPS paradigm. To this end, we tested differences in ERP amplitudes for conditioned stimuli associated (CS+) and not associated (CS-) with an aversive unconditioned stimulus (US) during fear acquisition. Participants included 54 female undergraduate students (mean age = 20.26). The FPS response was measured via electromyography of the orbicularis oculi muscle. EEG data were collected during the FPS paradigm. While the difference between CS+ and CS- P100 amplitude was not significant, LPP amplitudes were significantly enhanced following the CS+ relative to CS-. Furthermore, the LPP difference wave (CS+ minus CS-) was associated with FPS scores for the CS- during the later portion of fear acquisition. These findings suggest that conditioned stimuli may have altered emotional encoding (LPP) during the FPS paradigm. Thus, the LPP may be a promising neurophysiological marker that is related to fear learning processes. Copyright © 2018 Elsevier B.V. All rights reserved.

Modeling magnetic field and TEC signatures of large-amplitude acoustic and gravity waves generated by natural hazard events

NASA Astrophysics Data System (ADS)

Zettergren, M. D.; Snively, J. B.; Inchin, P.; Komjathy, A.; Verkhoglyadova, O. P.

2017-12-01

Ocean and solid earth responses during earthquakes are a significant source of large amplitude acoustic and gravity waves (AGWs) that perturb the overlying ionosphere-thermosphere (IT) system. IT disturbances are routinely detected following large earthquakes (M > 7.0) via GPS total electron content (TEC) observations, which often show acoustic wave ( 3-4 min periods) and gravity wave ( 10-15 min) signatures with amplitudes of 0.05-2 TECU. In cases of very large earthquakes (M > 8.0) the persisting acoustic waves are estimated to have 100-200 m/s compressional velocities in the conducting ionospheric E and F-regions and should generate significant dynamo currents and magnetic field signatures. Indeed, some recent reports (e.g. Hao et al, 2013, JGR, 118, 6) show evidence for magnetic fluctuations, which appear to be related to AGWs, following recent large earthquakes. However, very little quantitative information is available on: (1) the detailed spatial and temporal dependence of these magnetic fluctuations, which are usually observed at a small number of irregularly arranged stations, and (2) the relation of these signatures to TEC perturbations in terms of relative amplitudes, frequency, and timing for different events. This work investigates space- and time-dependent behavior of both TEC and magnetic fluctuations following recent large earthquakes, with the aim to improve physical understanding of these perturbations via detailed, high-resolution, two- and three-dimensional modeling case studies with a coupled neutral atmospheric and ionospheric model, MAGIC-GEMINI (Zettergren and Snively, 2015, JGR, 120, 9). We focus on cases inspired by the large Chilean earthquakes from the past decade (viz., the M > 8.0 earthquakes from 2010 and 2015) to constrain the sources for the model, i.e. size, frequency, amplitude, and timing, based on available information from ocean buoy and seismometer data. TEC data are used to validate source amplitudes and to constrain

Nonlinear Excitation of Acoustic Modes by Large Amplitude Alfvén waves in the Large Plasma Device (LAPD)

NASA Astrophysics Data System (ADS)

Dorfman, S.; Carter, T.; Pribyl, P.; Tripathi, S. K. P.; van Compernolle, B.; Vincena, S.; Sydora, R.

2013-10-01

Alfvén waves, a fundamental mode of magnetized plasmas, are ubiquitous in lab and space. While the linear behavior of these waves has been extensively studied, non-linear effects are important in many real systems, including the solar wind and solar corona. In particular, a parametric decay process in which a large amplitude Alfvén wave decays into an ion acoustic wave and backward propagating Alfvén wave may play an important role in coronal heating and/or in establishing the spectrum of solar wind turbulence. Recent counter-propagating Alfvén wave experiments have recorded the first laboratory observation of the Alfvén-acoustic mode coupling at the heart of this parametric decay instability. The resonance in the observed beat process has several features consistent with ponderomotive coupling to an ion acoustic mode, including the measured dispersion relation and spatial profile. Strong damping observed after the pump Alfvén waves are turned off is under investigation. New experiments and simulations also aim to identify decay instabilities from a single large-amplitude Alfvén wave. Supported by DOE and NSF.

Low-amplitude non-linear volume vibrations of single microbubbles measured with an "acoustical camera".

PubMed

Renaud, Guillaume; Bosch, Johan G; Van Der Steen, Antonius F W; De Jong, Nico

2014-06-01

Contrast-enhanced ultrasound imaging is based on the detection of non-linear vibrational responses of a contrast agent after its intravenous administration. Improving contrast-enhanced images requires an accurate understanding of the vibrational response to ultrasound of the lipid-coated gas microbubbles that constitute most ultrasound contrast agents. Variations in the volume of microbubbles provide the most efficient radiation of ultrasound and, therefore, are the most important bubble vibrations for medical diagnostic ultrasound imaging. We developed an "acoustical camera" that measures the dynamic volume change of individual microbubbles when excited by a pressure wave. In the work described here, the technique was applied to the characterization of low-amplitude non-linear behaviors of BR14 microbubbles (Bracco Research, Geneva, Switzerland). The amplitude dependence of the resonance frequency and the damping, the prevalence of efficient subharmonic and ultraharmonic vibrations and the amplitude dependence of the response at the fundamental frequency and at the second harmonic frequency were investigated. Because of the large number of measurements, we provide a statistical characterization of the low-amplitude non-linear properties of the contrast agent. Copyright © 2014 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Amplitude calibration of an acoustic backscattered signal from a bottom-moored ADCP based on long-term measurement series

NASA Astrophysics Data System (ADS)

Piotukh, V. B.; Zatsepin, A. G.; Kuklev, S. B.

2017-05-01

A possible approach to, and preliminary results of, amplitude calibration of acoustic signals backscattered from an ADCP moored at the bottom of the near-shelf zone of the Black Sea is considered. The aim of this work is to obtain vertical profiles of acoustic scattering signal levels, showing the real characteristics of the volume content of suspended sediments in sea water in units of conventional acoustic turbidity for a given signal frequency. In this case, the assumption about the intervals of maximum acoustic transparency and vertical homogeneity of the marine environment in long-term series of ADCP measurements is used. According to this hypothesis, the intervals of the least values of acoustic backscattered signals are detected, an empirical transfer function of the ADCP reception path is constructed, and it is calibrated. Normalized sets of acoustic backscattered signals relative to a signal from a level of conventionally clear water are obtained. New features in the behavior of vertical profiles of an acoustic echo-signal are revealed due to the calibration. The results of this work will be used in subsequent analysis of the vertical and time variations in suspended sediment content in the near-shelf zone of the Black Sea.

Arbitrary amplitude ion-acoustic solitary waves in electronegative plasmas with electrons featuring Tsallis distribution

NASA Astrophysics Data System (ADS)

Ghebache, Siham; Tribeche, Mouloud

2017-10-01

The problem of arbitrary amplitude ion-acoustic solitary waves (IASWs), which accompany electronegative plasmas having positive ions, negative ions, and nonextensive electrons is addressed. The energy integral equation with a new Sagdeev potential is analyzed to examine the existence regions of the IASWs. Different types of electronegative plasmas inspired from the experimental studies of Ichiki et al. (2001) are discussed. Our results show that in such plasmas IASWs, the amplitude and nature of which depend sensitively on the mass and density ratio of the positive and negative ions as well as the q-nonextensive parameter, can exist. Interestingly, one finds that our plasma model supports the coexistence of smooth rarefactive and spiky compressive IASWs. Our results complement and provide new insights on previously published findings on this problem.

Extreme startle and photomyoclonic response in severe hypocalcaemia.

PubMed

Moccia, Marcello; Erro, Roberto; Nicolella, Elvira; Striano, Pasquale; Striano, Salvatore

2014-03-01

We report the case of 62-year-old woman referred to our department because of a clinical suspicion of tonic-clonic seizures. Clinical examination revealed an exaggerated startle reflex, EEG showed a photomyoclonic response, and blood tests indicated severe hypocalcaemia. Additional clinical data, treatment strategies, and long-term follow-up visits were reported. The present report discusses the difficulties in distinguishing between epileptic and non-epileptic startles, and shows, for the first time, exaggerated startle reflex and extreme photomyoclonic response due to severe hypocalcaemia.

Effect of excess superthermal hot electrons on finite amplitude ion-acoustic solitons and supersolitons in a magnetized auroral plasma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rufai, O. R., E-mail: rrufai@csir.co.za; Bharuthram, R., E-mail: rbharuthram@uwc.ac.za; Singh, S. V., E-mail: satyavir@iigs.iigm.res.in

2015-10-15

The effect of excess superthermal electrons is investigated on finite amplitude nonlinear ion-acoustic waves in a magnetized auroral plasma. The plasma model consists of a cold ion fluid, Boltzmann distribution of cool electrons, and kappa distributed hot electron species. The model predicts the evolution of negative potential solitons and supersolitons at subsonic Mach numbers region, whereas, in the case of Cairn's nonthermal distribution model for the hot electron species studied earlier, they can exist both in the subsonic and supersonic Mach number regimes. For the dayside auroral parameters, the model generates the super-acoustic electric field amplitude, speed, width, and pulsemore » duration of about 18 mV/m, 25.4 km/s, 663 m, and 26 ms, respectively, which is in the range of the Viking spacecraft measurements.« less

Human ossicular-joint flexibility transforms the peak amplitude and width of impulsive acoustic stimulia)

PubMed Central

Gottlieb, Peter K.; Vaisbuch, Yona

2018-01-01

The role of the ossicular joints in the mammalian middle ear is still debated. This work tests the hypothesis that the two synovial joints filter potentially damaging impulsive stimuli by transforming both the peak amplitude and width of these impulses before they reach the cochlea. The three-dimensional (3D) velocity along the ossicular chain in unaltered cadaveric human temporal bones (N = 9), stimulated with acoustic impulses, is measured in the time domain using a Polytec (Waldbronn, Germany) CLV-3D laser Doppler vibrometer. The measurements are repeated after fusing one or both of the ossicular joints with dental cement. Sound transmission is characterized by measuring the amplitude, width, and delay of the impulsive velocity profile as it travels from the eardrum to the cochlea. On average, fusing both ossicular joints causes the stapes velocity amplitude and width to change by a factor of 1.77 (p = 0.0057) and 0.78 (p = 0.011), respectively. Fusing just the incudomalleolar joint has a larger effect on amplitude (a factor of 2.37), while fusing just the incudostapedial joint decreases the stapes velocity on average. The 3D motion of the ossicles is altered by fusing the joints. Finally, the ability of current computational models to predict this behavior is also evaluated.

Enhanced startle responsivity 24 hours after acute stress exposure.

PubMed

Herten, Nadja; Otto, Tobias; Adolph, Dirk; Pause, Bettina M; Kumsta, Robert; Wolf, Oliver T

2016-10-01

Cortisol release in a stressful situation can be beneficial for memory encoding and memory consolidation. Stimuli, such as odors, related to the stressful episode may successfully cue memory contents of the stress experience. The current investigation aimed at testing the potency of stress to influence startle responsivity 24 hr later and to implicitly reactivate emotional memory traces triggered by an odor involved. Participants were assigned to either a stress (Trier Social Stress Test [TSST]) or control (friendly TSST [f-TSST]) condition featuring an ambient odor. On the next day, participants underwent an auditory startle paradigm while their eyeblink reflex was recorded by an electrooculogram. Three different olfactory stimuli were delivered, one being the target odor presented the day before. Additionally, negative, positive, and pictures of the committee members were included for comparing general startle responsivity and fear-potentiated startle. Participants of the stress group demonstrated an enhanced startle response across all stimuli compared to participants of the control group. There were no specific effects with regard to the target odor. The typical fear-potentiated startle response occurred. Stressed participants tended to rate the target odor more aversive than control participants. Odor recognition memory did not differ between the groups, suggesting an implicit effect on odor valence. Our results show that acute stress exposure enhances startle responsivity 24 hr later. This effect might be caused by a shift of amygdala function causing heightened sensitivity, but lower levels of specificity. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

An Amplitude-Based Estimation Method for International Space Station (ISS) Leak Detection and Localization Using Acoustic Sensor Networks

NASA Technical Reports Server (NTRS)

Tian, Jialin; Madaras, Eric I.

2009-01-01

The development of a robust and efficient leak detection and localization system within a space station environment presents a unique challenge. A plausible approach includes the implementation of an acoustic sensor network system that can successfully detect the presence of a leak and determine the location of the leak source. Traditional acoustic detection and localization schemes rely on the phase and amplitude information collected by the sensor array system. Furthermore, the acoustic source signals are assumed to be airborne and far-field. Likewise, there are similar applications in sonar. In solids, there are specialized methods for locating events that are used in geology and in acoustic emission testing that involve sensor arrays and depend on a discernable phase front to the received signal. These methods are ineffective if applied to a sensor detection system within the space station environment. In the case of acoustic signal location, there are significant baffling and structural impediments to the sound path and the source could be in the near-field of a sensor in this particular setting.

Habituation of Auditory Steady State Responses Evoked by Amplitude-Modulated Acoustic Signals in Rats

PubMed Central

Prado-Gutierrez, Pavel; Castro-Fariñas, Anisleidy; Morgado-Rodriguez, Lisbet; Velarde-Reyes, Ernesto; Martínez, Agustín D.; Martínez-Montes, Eduardo

2015-01-01

Generation of the auditory steady state responses (ASSR) is commonly explained by the linear combination of random background noise activity and the stationary response. Based on this model, the decrease of amplitude that occurs over the sequential averaging of epochs of the raw data has been exclusively linked to the cancelation of noise. Nevertheless, this behavior might also reflect the non-stationary response of the ASSR generators. We tested this hypothesis by characterizing the ASSR time course in rats with different auditory maturational stages. ASSR were evoked by 8-kHz tones of different supra-threshold intensities, modulated in amplitude at 115 Hz. Results show that the ASSR amplitude habituated to the sustained stimulation and that dishabituation occurred when deviant stimuli were presented. ASSR habituation increased as animals became adults, suggesting that the ability to filter acoustic stimuli with no-relevant temporal information increased with age. Results are discussed in terms of the current model of the ASSR generation and analysis procedures. They might have implications for audiometric tests designed to assess hearing in subjects who cannot provide reliable results in the psychophysical trials. PMID:26557360

Alternative forms of axial startle behaviors in fishes.

PubMed

Liu, Yen-Chyi; Hale, Melina E

2014-02-01

For most aquatic vertebrates, axial movements play key roles in the performance of startle responses. In fishes, these axis-based startle behaviors fall into three distinct categories - the C-start, withdrawal, and S-start - defined by patterns of body bending and underlying motor control. Startle behaviors have been widely studied due to their importance for predator evasion. In addition, the neural circuits that control startles are relatively accessible, compared to other vertebrate circuits, and have provided opportunities to understand basic nervous system function. The C-start neural circuit has long been a model in systems neuroscience and considerable work on neural control of withdrawal response has been conducted in the larval lamprey. The S-start response has only recently been explored from a physiological perspective and we focus here on reviewing S-start motor control and movement in the context of the other two responses. Axial elongation has previously been associated with startle behavior in comparisons of C-starts and withdrawal, with extremely elongate animals performing withdrawals. We suggest that the S-start tends to occur with moderate body elongation, complementing the C-start in animals with this body form. As many larval fishes are moderately elongate, we suggest that the S-start may be common in larvae but may be secondarily lost with body shape change through development. Copyright © 2013 Elsevier GmbH. All rights reserved.

Multiphysics Simulation of Low-Amplitude Acoustic Wave Detection by Piezoelectric Wafer Active Sensors Validated by In-Situ AE-Fatigue Experiment

PubMed Central

Giurgiutiu, Victor

2017-01-01

Piezoelectric wafer active sensors (PWAS) are commonly used for detecting Lamb waves for structural health monitoring application. However, in most applications of active sensing, the signals are of high-amplitude and easy to detect. In this article, we have shown a new avenue of using the PWAS transducer for detecting the low-amplitude fatigue-crack related acoustic emission (AE) signals. Multiphysics finite element (FE) simulations were performed with two PWAS transducers bonded to the structure. Various configurations of the sensors were studied by using the simulations. One PWAS was placed near to the fatigue-crack and the other one was placed at a certain distance from the crack. The simulated AE event was generated at the crack tip. The simulation results showed that both PWAS transducers were capable of sensing the AE signals. To validate the multiphysics simulation results, an in-situ AE-fatigue experiment was performed. Two PWAS transducers were bonded to the thin aerospace test coupon. The fatigue crack was generated in the test coupon which had produced low-amplitude acoustic waves. The low-amplitude fatigue-crack related AE signals were successfully captured by the PWAS transducers. The distance effect on the captured AE signals was also studied. It has been shown that some high-frequency contents of the AE signal have developed as they travel away from the crack. PMID:28817081

Neural Network Burst Pressure Prediction in Graphite/Epoxy Pressure Vessels from Acoustic Emission Amplitude Data

NASA Technical Reports Server (NTRS)

Hill, Eric v. K.; Walker, James L., II; Rowell, Ginger H.

1995-01-01

Acoustic emission (AE) data were taken during hydroproof for three sets of ASTM standard 5.75 inch diameter filament wound graphite/epoxy bottles. All three sets of bottles had the same design and were wound from the same graphite fiber; the only difference was in the epoxies used. Two of the epoxies had similar mechanical properties, and because the acoustic properties of materials are a function of their stiffnesses, it was thought that the AE data from the two sets might also be similar; however, this was not the case. Therefore, the three resin types were categorized using dummy variables, which allowed the prediction of burst pressures all three sets of bottles using a single neural network. Three bottles from each set were used to train the network. The resin category, the AE amplitude distribution data taken up to 25 % of the expected burst pressure, and the actual burst pressures were used as inputs. Architecturally, the network consisted of a forty-three neuron input layer (a single categorical variable defining the resin type plus forty-two continuous variables for the AE amplitude frequencies), a fifteen neuron hidden layer for mapping, and a single output neuron for burst pressure prediction. The network trained on all three bottle sets was able to predict burst pressures in the remaining bottles with a worst case error of + 6.59%, slightly greater than the desired goal of + 5%. This larger than desired error was due to poor resolution in the amplitude data for the third bottle set. When the third set of bottles was eliminated from consideration, only four hidden layer neurons were necessary to generate a worst case prediction error of - 3.43%, well within the desired goal.

Corticosteroid dependent and independent effects of a cannabinoid agonist on core temperature, motor activity, and prepulse inhibition of the acoustic startle reflex in Wistar rats.

PubMed

Avdesh, Avdesh; Cornelisse, Vincent; Martin-Iverson, Mathew Thomas

2012-03-01

There are inconsistent reports on the effects of cannabinoid agonists on prepulse inhibition of the startle reflex (PPI) with increases, decreases, and no effects. It has been hypothesized that the conflicting observations may be as a result of modulation of the effects of cannabinoid agonists by the regulation of corticosteroid release. The purpose of the present study was to determine the effects of CP55940, a cannabinoid agonist, and metyrapone, a corticosteroid synthesis inhibitor on core temperature, motor activity, the startle reflex, and PPI. Startle responses were measured in 64 male Wistar rats while varying startling stimulus intensities, analogous to dose-response curves. A stimulus potency measure (ES(50)) and a response measure, the maximal achievable response (R (MAX)) were derived from the stimulus-response curves. CP55940 reduced core temperature and motor activity; these effects were potentiated by metyrapone. CP55940 increased R (MAX) of startle in the absence of a prepulse by a corticosteroid-dependent mechanism but decreased it when metyrapone was administered before CP55940, a corticosteroid-independent mechanism. The inverse of stimulus potency (ES(50)) was not affected by either drug alone but was increased by the combined drugs. CP55940 increased the prepulse motor gating effects and decreased the prepulse sensory gating effects of the same prepulses but only when given after metyrapone. The most parsimonious interpretation of these effects is that CP55940 has some effects through corticosteroid-dependent actions and opposite effects by corticosteroid-independent actions. These two putative sites of actions affect stimulus gating opposite to their effects on response gating.

Maternal buffering of fear-potentiated startle in children and adolescents with trauma exposure.

PubMed

van Rooij, Sanne J H; Cross, Dorthie; Stevens, Jennifer S; Vance, L Alexander; Kim, Ye Ji; Bradley, Bekh; Tottenham, Nim; Jovanovic, Tanja

2017-02-01

Parental availability influences fear expression and learning across species, but the effect of maternal buffering on fear learning in humans is unknown. Here we investigated the effect of maternal availability during fear conditioning in a group of children (ages 8-10) and adolescents (ages 11-13) from a low-income population with a range of trauma exposure. Acoustic startle response data were collected to measure fear-potentiated startle (FPS) in 104 participants. A total of 62 participants were tested with the mother available and 42 when the mother was not in the testing room. We observed that maternal availability during fear conditioning interacted with age to affect FPS discrimination between CS+ and CS-. In line with previous findings suggesting an absence of maternal buffering in adolescents, fear discrimination was affected by maternal availability only in children. Second, we observed that the effect of maternal buffering on FPS discrimination in children was not influenced by maternally reported warmth. In conclusion, we demonstrated that maternal availability improved discrimination in children, regardless of the quality of the relationship. Adolescents discriminated irrespective of maternal status, suggesting that childhood may be a sensitive period for environmental influences on key processes such as learning of danger and safety signals.

ENU-mutagenesis mice with a non-synonymous mutation in Grin1 exhibit abnormal anxiety-like behaviors, impaired fear memory, and decreased acoustic startle response

PubMed Central

2013-01-01

Background The Grin1 (glutamate receptor, ionotropic, NMDA1) gene expresses a subunit of N-methyl-D-aspartate (NMDA) receptors that is considered to play an important role in excitatory neurotransmission, synaptic plasticity, and brain development. Grin1 is a candidate susceptibility gene for neuropsychiatric disorders, including schizophrenia, bipolar disorder, and attention deficit/hyperactivity disorder (ADHD). In our previous study, we examined an N-ethyl-N-nitrosourea (ENU)-generated mutant mouse strain (Grin1Rgsc174/Grin1+) that has a non-synonymous mutation in Grin1. These mutant mice showed hyperactivity, increased novelty-seeking to objects, and abnormal social interactions. Therefore, Grin1Rgsc174/Grin1+ mice may serve as a potential animal model of neuropsychiatric disorders. However, other behavioral characteristics related to these disorders, such as working memory function and sensorimotor gating, have not been fully explored in these mutant mice. In this study, to further investigate the behavioral phenotypes of Grin1Rgsc174/Grin1+ mice, we subjected them to a comprehensive battery of behavioral tests. Results There was no significant difference in nociception between Grin1Rgsc174/Grin1+ and wild-type mice. The mutants did not display any abnormalities in the Porsolt forced swim and tail suspension tests. We confirmed the previous observations that the locomotor activity of these mutant mice increased in the open field and home cage activity tests. They displayed abnormal anxiety-like behaviors in the light/dark transition and the elevated plus maze tests. Both contextual and cued fear memory were severely deficient in the fear conditioning test. The mutant mice exhibited slightly impaired working memory in the eight-arm radial maze test. The startle amplitude was markedly decreased in Grin1Rgsc174/Grin1+ mice, whereas no significant differences between genotypes were detected in the prepulse inhibition (PPI) test. The mutant mice showed no obvious

Startle modulation and explicit valence evaluations dissociate during backward fear conditioning.

PubMed

Luck, Camilla C; Lipp, Ottmar V

2017-05-01

Blink startle magnitude is linearly modulated by affect such that, relative to neutral stimuli, startle magnitude is inhibited during pleasant stimuli and potentiated during unpleasant stimuli. Andreatta, Mühlberger, Yarali, Gerber, and Pauli (2010), however, report a dissociation between startle modulation and explicit valence evaluations during backward conditioning, a procedure in which the unconditional stimulus precedes the conditional stimulus (CS). Relative to controls, startles elicited during the CS were inhibited, suggesting that the CS had acquired positive valence, but participants still evaluated the CS as unpleasant after the experiment. In Experiment 1, we aimed to replicate this dissociation using a trial-by-trial measure of CS valence to measure startle modulation and CS valence simultaneously during forward and backward differential fear conditioning. In Experiment 2, we examined whether early and late portions of the CS could acquire differential valence by presenting startle probes at early and late probe positions during the CS. In both experiments, the dissociation between startle modulation and explicit valence evaluations in backward conditioning replicated, with CS+ evaluated as less pleasant than CS-, but startles elicited during CS+ inhibited relative to CS-. In Experiment 2, we provide preliminary evidence that this inhibition was present early, but not late, during the CS+. The results replicate the dissociation between implicit and explicit CS valence reported by Andreatta et al. (2010) using a trial-by-trial measure of valence. We also provide preliminary evidence that this dissociation may occur because the implicit and explicit measures are recorded at different times during the CS presentation. © 2017 Society for Psychophysiological Research.

A startling acoustic stimulus facilitates voluntary lower extremity movements and automatic postural responses in people with chronic stroke.

PubMed

Coppens, Milou J M; Roelofs, Jolanda M B; Donkers, Nicole A J; Nonnekes, Jorik; Geurts, Alexander C H; Weerdesteyn, Vivian

2018-05-14

A startling acoustic stimulus (SAS) involuntary releases prepared movements at accelerated latencies, known as the StartReact effect. Previous work has demonstrated intact StartReact in paretic upper extremity movements in people after stroke, suggesting preserved motor preparation. The question remains whether motor preparation of lower extremity movements is also unaffected after stroke. Here, we investigated StartReact effects on ballistic lower extremity movements and on automatic postural responses (APRs) following perturbations to standing balance. These APRs are particularly interesting as they are critical to prevent a fall following balance perturbations, but show substantial delays and poor muscle coordination after stroke. Twelve chronic stroke patients and 12 healthy controls performed voluntary ankle dorsiflexion movements in response to a visual stimulus, and responded to backward balance perturbations evoking APRs. Twenty-five percent of all trials contained a SAS (120 dB) simultaneously with the visual stimulus or balance perturbation. As expected, in the absence of a SAS muscle and movement onset latencies at the paretic side were delayed compared to the non-paretic leg and to controls. The SAS accelerated ankle dorsiflexion onsets in both the legs of the stroke subjects and in controls. Following perturbations, the SAS accelerated bilateral APR onsets not only in controls, but for the first time, we also demonstrated this effect in people after stroke. Moreover, APR inter- and intra-limb muscle coordination was rather weak in our stroke subjects, but substantially improved when the SAS was applied. These findings show preserved movement preparation, suggesting that there is residual (subcortical) capacity for motor recovery.

Amplitude sorting of oscillatory burst signals by sampling

DOEpatents

Davis, Thomas J.

1977-01-01

A method and apparatus for amplitude sorting of oscillatory burst signals is described in which the burst signal is detected to produce a burst envelope signal and an intermediate or midportion of such envelope signal is sampled to provide a sample pulse output. The height of the sample pulse is proportional to the amplitude of the envelope signal and to the maximum burst signal amplitude. The sample pulses are fed to a pulse height analyzer for sorting. The present invention is used in an acoustic emission testing system to convert the amplitude of the acoustic emission burst signals into sample pulse heights which are measured by a pulse height analyzer for sorting the pulses in groups according to their height in order to identify the material anomalies in the test material which emit the acoustic signals.

Dissecting genetic architecture of startle response in Drosophila melanogaster using multi-omics information.

PubMed

Xue, Angli; Wang, Hongcheng; Zhu, Jun

2017-09-28

Startle behavior is important for survival, and abnormal startle responses are related to several neurological diseases. Drosophila melanogaster provides a powerful system to investigate the genetic underpinnings of variation in startle behavior. Since mechanically induced, startle responses and environmental conditions can be readily quantified and precisely controlled. The 156 wild-derived fully sequenced lines of the Drosophila Genetic Reference Panel (DGRP) were used to identify SNPs and transcripts associated with variation in startle behavior. The results validated highly significant effects of 33 quantitative trait SNPs (QTSs) and 81 quantitative trait transcripts (QTTs) directly associated with phenotypic variation of startle response. We also detected QTT variation controlled by 20 QTSs (tQTSs) and 73 transcripts (tQTTs). Association mapping based on genomic and transcriptomic data enabled us to construct a complex genetic network that underlies variation in startle behavior. Based on principles of evolutionary conservation, human orthologous genes could be superimposed on this network. This study provided both genetic and biological insights into the variation of startle response behavior of Drosophila melanogaster, and highlighted the importance of genetic network to understand the genetic architecture of complex traits.

Discriminating Simulated Vocal Tremor Source Using Amplitude Modulation Spectra

PubMed Central

Carbonell, Kathy M.; Lester, Rosemary A.; Story, Brad H.; Lotto, Andrew J.

2014-01-01

Objectives/Hypothesis Sources of vocal tremor are difficult to categorize perceptually and acoustically. This paper describes a preliminary attempt to discriminate vocal tremor sources through the use of spectral measures of the amplitude envelope. The hypothesis is that different vocal tremor sources are associated with distinct patterns of acoustic amplitude modulations. Study Design Statistical categorization methods (discriminant function analysis) were used to discriminate signals from simulated vocal tremor with different sources using only acoustic measures derived from the amplitude envelopes. Methods Simulations of vocal tremor were created by modulating parameters of a vocal fold model corresponding to oscillations of respiratory driving pressure (respiratory tremor), degree of vocal fold adduction (adductory tremor) and fundamental frequency of vocal fold vibration (F0 tremor). The acoustic measures were based on spectral analyses of the amplitude envelope computed across the entire signal and within select frequency bands. Results The signals could be categorized (with accuracy well above chance) in terms of the simulated tremor source using only measures of the amplitude envelope spectrum even when multiple sources of tremor were included. Conclusions These results supply initial support for an amplitude-envelope based approach to identify the source of vocal tremor and provide further evidence for the rich information about talker characteristics present in the temporal structure of the amplitude envelope. PMID:25532813

Neural Network Prediction of Aluminum-Lithium Weld Strengths from Acoustic Emission Amplitude Data

NASA Technical Reports Server (NTRS)

Hill, Eric v. K.; Israel, Peggy L.; Knotts, Gregory L.

1993-01-01

Acoustic Emission (AE) flaw growth activity was monitored in aluminum-lithium weld specimens from the onset tensile loading to failure. Data on actual ultimate strengths together with AE data from the beginning of loading up to 25 percent of the expected ultimate strength were used to train a backpropagation neural network to predict ultimate strengths. Architecturally, the fully interconnected network consisted of an input layer for the AE amplitude data, a hidden layer to accommodate failure mechanism mapping, and an output layer for ultimate strength prediction. The trained network was the applied to the prediction of ultimate strengths in the remaining six specimens. The worst case prediction error was found to be +2.6 percent.

Whiplash evokes descending muscle recruitment and sympathetic responses characteristic of startle

PubMed Central

Mang, Daniel WH; Siegmund, Gunter P; Blouin, Jean-Sébastien

2014-01-01

Whiplash injuries are the most common injuries following rear-end collisions. During a rear-end collision, the human muscle response consists of both a postural and a startle response that may exacerbate injury. However, most previous studies only assessed the presence of startle using data collected from the neck muscles and head/neck kinematics. The startle response also evokes a descending pattern of muscle recruitment and changes in autonomic activity. Here we examined the recruitment of axial and appendicular muscles along with autonomic responses to confirm whether these other features of a startle response were present during the first exposure to a whiplash perturbation. Ten subjects experienced a single whiplash perturbation while recording electromyography, electrocardiogram, and electrodermal responses. All subjects exhibited a descending pattern of muscle recruitment, and increasing heart rate and electrodermal responses following the collision. Our results provide further support that the startle response is a component of the response to whiplash collisions. PMID:24932015

Gap prepulse inhibition and auditory brainstem-evoked potentials as objective measures for tinnitus in guinea pigs

PubMed Central

Dehmel, Susanne; Eisinger, Daniel; Shore, Susan E.

2012-01-01

Tinnitus or ringing of the ears is a subjective phantom sensation necessitating behavioral models that objectively demonstrate the existence and quality of the tinnitus sensation. The gap detection test uses the acoustic startle response elicited by loud noise pulses and its gating or suppression by preceding sub-startling prepulses. Gaps in noise bands serve as prepulses, assuming that ongoing tinnitus masks the gap and results in impaired gap detection. This test has shown its reliability in rats, mice, and gerbils. No data exists for the guinea pig so far, although gap detection is similar across mammals and the acoustic startle response is a well-established tool in guinea pig studies of psychiatric disorders and in pharmacological studies. Here we investigated the startle behavior and prepulse inhibition (PPI) of the guinea pig and showed that guinea pigs have a reliable startle response that can be suppressed by 15 ms gaps embedded in narrow noise bands preceding the startle noise pulse. After recovery of auditory brainstem response (ABR) thresholds from a unilateral noise over-exposure centered at 7 kHz, guinea pigs showed diminished gap-induced reduction of the startle response in frequency bands between 8 and 18 kHz. This suggests the development of tinnitus in frequency regions that showed a temporary threshold shift (TTS) after noise over-exposure. Changes in discharge rate and synchrony, two neuronal correlates of tinnitus, should be reflected in altered ABR waveforms, which would be useful to objectively detect tinnitus and its localization to auditory brainstem structures. Therefore, we analyzed latencies and amplitudes of the first five ABR waves at suprathreshold sound intensities and correlated ABR abnormalities with the results of the behavioral tinnitus testing. Early ABR wave amplitudes up to N3 were increased for animals with tinnitus possibly stemming from hyperactivity and hypersynchrony underlying the tinnitus percept. Animals that did not

Effects of anticipated emotional category and temporal predictability on the startle reflex.

PubMed

Parisi, Elizabeth A; Hajcak, Greg; Aneziris, Eleni; Nelson, Brady D

2017-09-01

Anticipated emotional category and temporal predictability are key characteristics that have both been shown to impact psychophysiological indices of defensive motivation (e.g., the startle reflex). To date, research has primarily examined these features in isolation, and it is unclear whether they have additive or interactive effects on defensive motivation. In the present study, the startle reflex was measured in anticipation of low arousal neutral, moderate arousal pleasant, and high arousal unpleasant pictures that were presented with either predictable or unpredictable timing. Linear mixed-effects modeling was conducted to examine startle magnitude across time, and the intercept at the beginning and end of the task. Across the entire task, the anticipation of temporally unpredictable (relative to predictable) pictures and emotional (relative to neutral) pictures potentiated startle magnitude, but there was no interaction between the two features. However, examination of the intercept at the beginning of the task indicated a Predictability by Emotional Category interaction, such that temporal unpredictability enhanced startle potentiation in anticipation of unpleasant pictures only. Examination of the intercept at the end of the task indicated that the effects of predictability and emotional category on startle magnitude were largely diminished. The present study replicates previous reports demonstrating that emotional category and temporal predictability impact the startle reflex, and provides novel evidence suggesting an interactive effect on defensive motivation at the beginning of the task. This study also highlights the importance of examining the time course of the startle reflex. Copyright © 2017 Elsevier B.V. All rights reserved.

Emotion-modulated startle in psychopathy: Clarifying familiar effects

PubMed Central

Baskin-Sommers, Arielle R.; Curtin, John J.; Newman, Joseph P.

2012-01-01

The behavior of psychopathic individuals is thought to reflect a core fear deficit that prevents these individuals from appreciating the consequences of their choices and actions. However, growing evidence suggests that psychopathy-related emotion deficits are moderated by attention and, thus, may not reflect a reduced capacity for emotion responding. The present study attempts to reconcile this attention perspective with one of the most cited findings in psychopathy, which reports emotion-modulated startle deficits among psychopathic individuals during picture viewing. In this study, we evaluate the potential effects of a putative attention bottleneck on the emotion processing of psychopathic offenders during picture viewing by manipulating picture familiarity and examining emotion-modulated startle and late positive potential (LPP). As predicted, psychopathic individuals displayed the classic deficit in emotion-modulated startle during novel pictures, but they showed no deficit in emotion-modulated startle during familiar pictures. Conversely, results for LPP responses revealed psychopathy-related differences during familiar pictures and no psychopathy-related differences during novel pictures. Important differences related to the two Factors of psychopathy are also discussed. Overall, the results of this study not only highlight the differential importance of perceptual load on emotion processing in psychopathy, but also raise interesting questions about the varied effects of attention on psychopathy-related emotion deficits. PMID:23356218

Unilateral block of NMDA receptors in the amygdala prevents predator stress-induced lasting increases in anxiety-like behavior and unconditioned startle--effective hemisphere depends on the behavior.

PubMed

Adamec, R E; Burton, P; Shallow, T; Budgell, J

Lasting increases in anxiety-like behavior (ALB) in the elevated plus-maze are produced by a single 5-min exposure of a rat to a cat. Rats become more anxious in the plus-maze for up to 3 weeks after the exposure. The first study in this series demonstrated that blockade of NMDA receptors in rats with MK-801, AP7, or CPP, given systemically 30 min prior to exposure to a cat prevents the increase in ALB assessed 1 week later in the elevated plus-maze. To localize the site of action of systemic MK-801, MK-801 was injected in the amygdala 30 min prior to predator stress. Injections were given either unilaterally in either hemisphere, or bilaterally in both hemispheres. The target of the injection was the basolateral amygdala. The effects of injection depended on both the type of behavior and the hemisphere of injection. Injections of MK-801 in a variety of sites in the basolateral amygdala had no effect on the suppression of open-arm exploration produced by predator stress. Other amygdala nuclei or other limbic sites likely mediate the effects of systemically administered MK-801 on this behavior. In contrast, NMDA receptors in the left lateral amygdala mediate lasting suppression of risk assessment. MK-801, in a variety of sites in the left but not right lateral amygdala, blocked the effects of predator stress on risk assessment. This is clear evidence of separability of neural mechanisms controlling open-arm exploration and risk assessment. Different NMDA-dependent amygdala circuitry mediated effects of predator stress on unconditioned acoustic startle 1 week after cat exposure. The data indicate that integrity of the left lateral amygdala is necessary for potentiation of startle amplitude by predator stress, though NMDA receptors are not involved in this function. Nevertheless, NMDA receptors in the right, but not the left lateral amygdala, mediate initiation of changes in startle. The data also suggest that the right amygdala action is "downstream" from the left

Does intolerance of uncertainty predict anticipatory startle responses to uncertain threat?

PubMed

Nelson, Brady D; Shankman, Stewart A

2011-08-01

Intolerance of uncertainty (IU) has been proposed to be an important maintaining factor in several anxiety disorders, including generalized anxiety disorder, obsessive-compulsive disorder, and social phobia. While IU has been shown to predict subjective ratings and decision-making during uncertain/ambiguous situations, few studies have examined whether IU also predicts emotional responding to uncertain threat. The present study examined whether IU predicted aversive responding (startle and subjective ratings) during the anticipation of temporally uncertain shocks. Sixty-nine participants completed three experimental conditions during which they received: no shocks, temporally certain/predictable shocks, and temporally uncertain shocks. Results indicated that IU was negatively associated with startle during the uncertain threat condition in that those with higher IU had a smaller startle response. IU was also only related to startle during the uncertain (and not the certain/predictable) threat condition, suggesting that it was not predictive of general aversive responding, but specific to responses to uncertain aversiveness. Perceived control over anxiety-related events mediated the relation between IU and startle to uncertain threat, such that high IU led to lowered perceived control, which in turn led to a smaller startle response. We discuss several potential explanations for these findings, including the inhibitory qualities of IU. Overall, our results suggest that IU is associated with attenuated aversive responding to uncertain threat. Copyright © 2011 Elsevier B.V. All rights reserved.

Self-demodulation of amplitude-modulated signal components in amplitude-modulated bone-conducted ultrasonic hearing

NASA Astrophysics Data System (ADS)

Ito, Kazuhito; Nakagawa, Seiji

2015-07-01

A novel hearing aid system utilizing amplitude-modulated bone-conducted ultrasound (AM-BCU) is being developed for use by profoundly deaf people. However, there is a lack of research on the acoustic aspects of AM-BCU hearing. In this study, acoustic fields in the ear canal under AM-BCU stimulation were examined with respect to the self-demodulation effect of amplitude-modulated signal components generated in the ear canal. We found self-demodulated signals with an audible sound pressure level related to the amplitude-modulated signal components of bone-conducted ultrasonic stimulation. In addition, the increases in the self-demodulated signal levels at low frequencies in the ear canal after occluding the ear canal opening, i.e., the positive occlusion effect, indicate the existence of a pathway by which the self-demodulated signals pass through the aural cartilage and soft tissue, and radiate into the ear canal.

Glycine inhibits startle-mediating neurons in the caudal pontine reticular formation but is not involved in synaptic depression underlying short-term habituation of startle.

PubMed

Geis, Hans-Ruediger; Schmid, Susanne

2011-10-01

The mammalian startle response is controlled by glycine inhibition in the spinal cord. Evidence for additional glycine inhibition on the level of the brainstem, namely in the caudal pontine reticular nucleus (PnC), is controversial. Startle mediating PnC neurons receive fast input from sensory pathways and project to cranial and spinal motoneurons. Synaptic depression in the sensory synapses in the PnC has been indicated as underlying mechanism of short-term habituation of startle. We here performed patch-clamp recordings of PnC giant neurons in rat brain slices to test the hypothesis that the activation of glycine receptors inhibits PnC neurons and that this inhibition is involved in synaptic depression in the PnC. Glycine strongly inhibited PnC neuron activity and synaptic signalling, indicating that functional glycine receptors mediate a powerful inhibition of PnC neurons over a wide range of glycine concentrations. Strychnine reversed all glycine effects, but had no effect on PnC neurons itself. Thus, we found no evidence for a tonic glycine inhibition or for glycine activation within the primary startle pathway indicating that baseline startle reactions are unlikely to be controlled by glycine in the PnC. Most importantly, synaptic depression underlying short-term habituation was not affected by glycine or strychnine. Copyright © 2011 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.

Hypnotizability and Placebo Analgesia in Waking and Hypnosis as Modulators of Auditory Startle Responses in Healthy Women: An ERP Study.

PubMed

De Pascalis, Vilfredo; Scacchia, Paolo

2016-01-01

We evaluated the influence of hypnotizability, pain expectation, placebo analgesia in waking and hypnosis on tonic pain relief. We also investigated how placebo analgesia affects somatic responses (eye blink) and N100 and P200 waves of event-related potentials (ERPs) elicited by auditory startle probes. Although expectation plays an important role in placebo and hypnotic analgesia, the neural mechanisms underlying these treatments are still poorly understood. We used the cold cup test (CCT) to induce tonic pain in 53 healthy women. Placebo analgesia was initially produced by manipulation, in which the intensity of pain induced by the CCT was surreptitiously reduced after the administration of a sham analgesic cream. Participants were then tested in waking and hypnosis under three treatments: (1) resting (Baseline); (2) CCT-alone (Pain); and (3) CCT plus placebo cream for pain relief (Placebo). For each painful treatment, we assessed pain and distress ratings, eye blink responses, N100 and P200 amplitudes. We used LORETA analysis of N100 and P200 waves, as elicited by auditory startle, to identify cortical regions sensitive to pain reduction through placebo and hypnotic analgesia. Higher pain expectation was associated with higher pain reductions. In highly hypnotizable participants placebo treatment produced significant reductions of pain and distress perception in both waking and hypnosis condition. P200 wave, during placebo analgesia, was larger in the frontal left hemisphere while placebo analgesia, during hypnosis, involved the activity of the left hemisphere including the occipital region. These findings demonstrate that hypnosis and placebo analgesia are different processes of top-down regulation. Pain reduction was associated with larger EMG startle amplitudes, N100 and P200 responses, and enhanced activity within the frontal, parietal, and anterior and posterior cingulate gyres. LORETA results showed that placebo analgesia modulated pain-responsive areas

Hypnotizability and Placebo Analgesia in Waking and Hypnosis as Modulators of Auditory Startle Responses in Healthy Women: An ERP Study

PubMed Central

De Pascalis, Vilfredo; Scacchia, Paolo

2016-01-01

We evaluated the influence of hypnotizability, pain expectation, placebo analgesia in waking and hypnosis on tonic pain relief. We also investigated how placebo analgesia affects somatic responses (eye blink) and N100 and P200 waves of event-related potentials (ERPs) elicited by auditory startle probes. Although expectation plays an important role in placebo and hypnotic analgesia, the neural mechanisms underlying these treatments are still poorly understood. We used the cold cup test (CCT) to induce tonic pain in 53 healthy women. Placebo analgesia was initially produced by manipulation, in which the intensity of pain induced by the CCT was surreptitiously reduced after the administration of a sham analgesic cream. Participants were then tested in waking and hypnosis under three treatments: (1) resting (Baseline); (2) CCT-alone (Pain); and (3) CCT plus placebo cream for pain relief (Placebo). For each painful treatment, we assessed pain and distress ratings, eye blink responses, N100 and P200 amplitudes. We used LORETA analysis of N100 and P200 waves, as elicited by auditory startle, to identify cortical regions sensitive to pain reduction through placebo and hypnotic analgesia. Higher pain expectation was associated with higher pain reductions. In highly hypnotizable participants placebo treatment produced significant reductions of pain and distress perception in both waking and hypnosis condition. P200 wave, during placebo analgesia, was larger in the frontal left hemisphere while placebo analgesia, during hypnosis, involved the activity of the left hemisphere including the occipital region. These findings demonstrate that hypnosis and placebo analgesia are different processes of top-down regulation. Pain reduction was associated with larger EMG startle amplitudes, N100 and P200 responses, and enhanced activity within the frontal, parietal, and anterior and posterior cingulate gyres. LORETA results showed that placebo analgesia modulated pain-responsive areas

Voluntary emotion regulation in anorexia nervosa: A preliminary emotion-modulated startle investigation.

PubMed

Racine, Sarah E; Forbush, Kelsie T; Wildes, Jennifer E; Hagan, Kelsey E; Pollack, Lauren O; May, Casey

2016-06-01

Emotion regulation difficulties are implicated in the development and maintenance of anorexia nervosa (AN). However, research has been limited by an almost exclusive reliance on self-report. This study is the first to use the emotion-modulated startle paradigm (EMSP) to investigate emotional reactivity and voluntary emotion regulation in individuals with AN. Twenty women with AN viewed negative, positive, neutral, and food images and were asked to enhance, suppress, or maintain their emotional responses mid-way through picture presentation. Startle eyeblink magnitudes in response to startle probes administered prior, and subsequent, to regulation instructions indexed emotional reactivity and regulation, respectively. On emotional reactivity trials, startle magnitudes were greater for negative, positive, and food images, compared to neutral images. Participants had difficulty suppressing startle responses to negative and food images, as indicated by non-significant suppress-maintain comparisons. In contrast, startle responses to enhance and suppress cues during presentation of pleasant images were comparable and significantly lower than maintain cues. Findings converge with self-report data to suggest that patients with AN have difficulties with voluntary emotion regulation. The EMSP may be a promising trans-diagnostic method for examining emotion regulation difficulties that underlie risk for eating disorders and other psychiatric conditions. Copyright © 2016 Elsevier Ltd. All rights reserved.

Differential phase acoustic microscope for micro-NDE

NASA Technical Reports Server (NTRS)

Waters, David D.; Pusateri, T. L.; Huang, S. R.

1992-01-01

A differential phase scanning acoustic microscope (DP-SAM) was developed, fabricated, and tested in this project. This includes the acoustic lens and transducers, driving and receiving electronics, scanning stage, scanning software, and display software. This DP-SAM can produce mechanically raster-scanned acoustic microscopic images of differential phase, differential amplitude, or amplitude of the time gated returned echoes of the samples. The differential phase and differential amplitude images provide better image contrast over the conventional amplitude images. A specially designed miniature dual beam lens was used to form two foci to obtain the differential phase and amplitude information of the echoes. High image resolution (1 micron) was achieved by applying high frequency (around 1 GHz) acoustic signals to the samples and placing two foci close to each other (1 micron). Tone burst was used in this system to obtain a good estimation of the phase differences between echoes from the two adjacent foci. The system can also be used to extract the V(z) acoustic signature. Since two acoustic beams and four receiving modes are available, there are 12 possible combinations to produce an image or a V(z) scan. This provides a unique feature of this system that none of the existing acoustic microscopic systems can provide for the micro-nondestructive evaluation applications. The entire system, including the lens, electronics, and scanning control software, has made a competitive industrial product for nondestructive material inspection and evaluation and has attracted interest from existing acoustic microscope manufacturers.

Interacting Multiscale Acoustic Vortices as Coherent Excitations in Dust Acoustic Wave Turbulence

NASA Astrophysics Data System (ADS)

Lin, Po-Cheng; I, Lin

2018-03-01

In this work, using three-dimensional intermittent dust acoustic wave turbulence in a dusty plasma as a platform and multidimensional empirical mode decomposition into different-scale modes in the 2 +1 D spatiotemporal space, we demonstrate the experimental observation of the interacting multiscale acoustic vortices, winding around wormlike amplitude hole filaments coinciding with defect filaments, as the basic coherent excitations for acoustic-type wave turbulence. For different decomposed modes, the self-similar rescaled stretched exponential lifetime histograms of amplitude hole filaments, and the self-similar power spectra of dust density fluctuations, indicate that similar dynamical rules are followed over a wide range of scales. In addition to the intermode acoustic vortex pair generation, propagation, or annihilation, the intra- and intermode interactions of acoustic vortices with the same or opposite helicity, their entanglement and synchronization, are found to be the key dynamical processes in acoustic wave turbulence, akin to the interacting multiscale vortices around wormlike cores observed in hydrodynamic turbulence.

Arbitrary amplitude nucleus-acoustic solitons in multi-ion quantum plasmas with relativistically degenerate electrons

NASA Astrophysics Data System (ADS)

Sultana, S.; Schlickeiser, R.

2018-02-01

A three component degenerate relativistic quantum plasma (consisting of relativistically degenerate electrons, nondegenerate inertial light nuclei, and stationary heavy nuclei) is considered to model the linear wave and also the electrostatic solitary waves in the light nuclei-scale length. A well-known normal mode analysis is employed to investigate the linear wave properties. A mechanical-motion analog (Sagdeev-type) pseudo-potential approach, which reveals the existence of large amplitude solitary excitations, is adopted to study the nonlinear wave properties. Only the positive potential solitary excitations are found to exist in the plasma medium under consideration. The basic properties of the arbitrary amplitude electrostatic acoustic modes in the light nuclei-scale length and their existence domain in terms of soliton speed (Mach number) are examined. The modifications of solitary wave characteristics and their existence domain with the variation of different key plasma configuration parameters (e.g., electrons degeneracy parameter, inertial light nuclei number density, and degenerate electron number density) are also analyzed. Our results, which may be helpful to explain the basic features of the nonlinear wave propagation in multi-component degenerate quantum plasmas, in connection with astrophysical compact objects (e.g., white dwarfs) are briefly discussed.

A cost minimisation and Bayesian inference model predicts startle reflex modulation across species.

PubMed

Bach, Dominik R

2015-04-07

In many species, rapid defensive reflexes are paramount to escaping acute danger. These reflexes are modulated by the state of the environment. This is exemplified in fear-potentiated startle, a more vigorous startle response during conditioned anticipation of an unrelated threatening event. Extant explanations of this phenomenon build on descriptive models of underlying psychological states, or neural processes. Yet, they fail to predict invigorated startle during reward anticipation and instructed attention, and do not explain why startle reflex modulation evolved. Here, we fill this lacuna by developing a normative cost minimisation model based on Bayesian optimality principles. This model predicts the observed pattern of startle modification by rewards, punishments, instructed attention, and several other states. Moreover, the mathematical formalism furnishes predictions that can be tested experimentally. Comparing the model with existing data suggests a specific neural implementation of the underlying computations which yields close approximations to the optimal solution under most circumstances. This analysis puts startle modification into the framework of Bayesian decision theory and predictive coding, and illustrates the importance of an adaptive perspective to interpret defensive behaviour across species. Copyright © 2015 The Author. Published by Elsevier Ltd.. All rights reserved.

Retrieving acoustic energy densities and local pressure amplitudes in microfluidics by holographic time-lapse imaging.

PubMed

Cacace, Teresa; Bianco, Vittorio; Paturzo, Melania; Memmolo, Pasquale; Vassalli, Massimo; Fraldi, Massimiliano; Mensitieri, Giuseppe; Ferraro, Pietro

2018-06-26

The development of techniques able to characterize and map the pressure field is crucial for the widespread use of acoustofluidic devices in biotechnology and lab-on-a-chip platforms. In fact, acoustofluidic devices are powerful tools for driving precise manipulation of microparticles and cells in microfluidics in non-contact modality. Here, we report a full and accurate characterization of the movement of particles subjected to acoustophoresis in a microfluidic environment by holographic imaging. The particle displacement along the direction of the ultrasound wave propagation, coinciding with the optical axis, is observed and investigated. Two resonance frequencies are explored, varying for each the amplitude of the applied signal. The trajectories of individual tracers, accomplished by holographic measurements, are fitted with the theoretical model thus allowing the retrieval of the acoustic energy densities and pressure amplitudes through full holographic analysis. The absence of prior calibration, being independent of the object shape and the possibility of implementing automatic analysis make the use of holography very appealing for applications in devices for biotechnologies.

Spectral statistics of the acoustic stadium

NASA Astrophysics Data System (ADS)

Méndez-Sánchez, R. A.; Báez, G.; Leyvraz, F.; Seligman, T. H.

2014-01-01

We calculate the normal-mode frequencies and wave amplitudes of the two-dimensional acoustical stadium. We also obtain the statistical properties of the acoustical spectrum and show that they agree with the results given by random matrix theory. Some normal-mode wave amplitudes showing scarring are presented.

Does anxiety sensitivity correlate with startle habituation? An examination in two independent samples.

PubMed

Campbell, Miranda L; Gorka, Stephanie M; McGowan, Sarah K; Nelson, Brady D; Sarapas, Casey; Katz, Andrea C; Robison-Andrew, E Jenna; Shankman, Stewart A

2014-01-01

Individuals with anxiety disorders have previously demonstrated abnormal habituation to aversiveness over time. As anxiety sensitivity (AS), or an individuals' propensity to fear of anxiety-related sensations, has been shown to be a risk factor for anxiety disorders (particularly panic disorder), the present study examined whether AS was also associated with abnormal habituation. This association was examined in two independent samples of undergraduates (Ntotal=178). Habituation was operationalised as the reduction in startle response to multiple startle probes presented over 2.5 minutes and three definitions of this reduction were employed. Results indicated that individuals with higher levels of AS evidenced deficits in startle habituation, but the strength of this relationship was somewhat dependent on the definition of startle habituation, with the most robust definition being an analysis of participants' individual slopes across all nine blinks. The present findings suggest that startle habituation is a key mechanism underlying AS, and may help elucidate the role this risk factor plays in the pathogenesis of anxiety disorders.

Control of broadband optically generated ultrasound pulses using binary amplitude holograms.

PubMed

Brown, Michael D; Jaros, Jiri; Cox, Ben T; Treeby, Bradley E

2016-04-01

In this work, the use of binary amplitude holography is investigated as a mechanism to focus broadband acoustic pulses generated by high peak-power pulsed lasers. Two algorithms are described for the calculation of the binary holograms; one using ray-tracing, and one using an optimization based on direct binary search. It is shown using numerical simulations that when a binary amplitude hologram is excited by a train of laser pulses at its design frequency, the acoustic field can be focused at a pre-determined distribution of points, including single and multiple focal points, and line and square foci. The numerical results are validated by acoustic field measurements from binary amplitude holograms, excited by a high peak-power laser.

Amplitude modulation of quantum-ion-acoustic wavepackets in electron-positron-ion plasmas: Modulational instability, envelope modes, extreme wavesa)

NASA Astrophysics Data System (ADS)

Rahman, Ata-ur-; Kerr, Michael Mc; El-Taibany, Wael F.; Kourakis, Ioannis; Qamar, A.

2015-02-01

A semirelativistic fluid model is employed to describe the nonlinear amplitude modulation of low-frequency (ionic scale) electrostatic waves in an unmagnetized electron-positron-ion plasma. Electrons and positrons are assumed to be degenerated and inertialess, whereas ions are warm and classical. A multiscale perturbation method is used to derive a nonlinear Schrödinger equation for the envelope amplitude, based on which the occurrence of modulational instability is investigated in detail. Various types of localized ion acoustic excitations are shown to exist, in the form of either bright type envelope solitons (envelope pulses) or dark-type envelope solitons (voids, holes). The plasma configurational parameters (namely, the relativistic degeneracy parameter, the positron concentration, and the ionic temperature) are shown to affect the conditions for modulational instability significantly, in fact modifying the associated threshold as well as the instability growth rate. In particular, the relativistic degeneracy parameter leads to an enhancement of the modulational instability mechanism. Furthermore, the effect of different relevant plasma parameters on the characteristics (amplitude, width) of these envelope solitary structures is also presented in detail. Finally, the occurrence of extreme amplitude excitation (rogue waves) is also discussed briefly. Our results aim at elucidating the formation and dynamics of nonlinear electrostatic excitations in superdense astrophysical regimes.

Formant Amplitude of Children with Down's Syndrome.

ERIC Educational Resources Information Center

Pentz, Arthur L., Jr.

1987-01-01

The sustained vowel sounds of 14 noninstitutionalized 7- to 10-year-old children with Down's syndrome were analyzed acoustically for vowel formant amplitude levels. The subjects with Down's syndrome had formant amplitude intensity levels significantly lower than those of a similar group of speakers without Down's syndrome. (Author/DB)

Increased fear-potentiated startle in major depressive disorder patients with lifetime history of suicide attempt.

PubMed

Ballard, Elizabeth D; Ionescu, Dawn F; Vande Voort, Jennifer L; Slonena, Elizabeth E; Franco-Chaves, Jose A; Zarate, Carlos A; Grillon, Christian

2014-06-01

Suicide is a common reason for psychiatric emergency and morbidity, with few effective treatments. Anxiety symptoms have emerged as potential modifiable risk factors in the time before a suicide attempt, but few studies have been conducted using laboratory measures of fear and anxiety. We operationally defined fear and anxiety as increased startle reactivity during anticipation of predictable (fear-potentiated startle) and unpredictable (anxiety-potentiated startle) shock. We hypothesized that a lifetime history of suicide attempt (as compared to history of no suicide attempt) would be associated with increased fear-potentiated startle. A post-hoc analysis of fear- and anxiety-potentiated startle was conducted in 28 medication-free patients with Major Depressive Disorder (MDD) divided according to suicide attempt history. The magnitude of fear-potentiated startle was increased in depressed patients with lifetime suicide attempts compared to those without a lifetime history of suicide attempt (F(1,26)=5.629, p=.025). There was no difference in anxiety-potentiated startle by suicide attempt history. This is a post-hoc analysis of previously analyzed patient data from a study of depressed inpatients. Further replication of the finding with a larger patient sample is indicated. Increased fear-potentiated startle in suicide attempters suggests the role of amygdala in depressed patients with a suicide attempt history. Findings highlight the importance of anxiety symptoms in the treatment of patients at increased suicide risk. Published by Elsevier B.V.

Relationship between the Amplitude and Phase of a Signal Scattered by a Point-Like Acoustic Inhomogeneity

NASA Astrophysics Data System (ADS)

Burov, V. A.; Morozov, S. A.

2001-11-01

Wave scattering by a point-like inhomogeneity, i.e., a strong inhomogeneity with infinitesimal dimensions, is described. This type of inhomogeneity model is used in investigating the point-spread functions of different algorithms and systems. Two approaches are used to derive the rigorous relationship between the amplitude and phase of a signal scattered by a point-like acoustic inhomogeneity. The first approach is based on a Marchenko-type equation. The second approach uses the scattering by a scatterer whose size decreases simultaneously with an increase in its contrast. It is shown that the retarded and advanced waves are scattered differently despite the relationship between the phases of the corresponding scattered waves.

Intolerance of uncertainty and startle potentiation in relation to different threat reinforcement rates.

PubMed

Chin, Brian; Nelson, Brady D; Jackson, Felicia; Hajcak, Greg

2016-01-01

Fear conditioning research on threat predictability has primarily examined the impact of temporal (i.e., timing) predictability on the startle reflex. However, there are other key features of threat that can vary in predictability. For example, the reinforcement rate (i.e., frequency) of threat is a crucial factor underlying fear learning. The present study examined the impact of threat reinforcement rate on the startle reflex and self-reported anxiety during a fear conditioning paradigm. Forty-five participants completed a fear learning task in which the conditioned stimulus was reinforced with an electric shock to the forearm on 50% of trials in one block and 75% of trials in a second block, in counter-balanced order. The present study also examined whether intolerance of uncertainty (IU), the tendency to perceive or experience uncertainty as stressful or unpleasant, was associated with the startle reflex during conditions of low (50%) vs. high (75%) reinforcement. Results indicated that, across all participants, startle was greater during the 75% relative to the 50% reinforcement condition. IU was positively correlated with startle potentiation (i.e., increased startle response to the CS+ relative to the CS-) during the 50%, but not the 75%, reinforcement condition. Thus, despite receiving fewer electric shocks during the 50% reinforcement condition, individuals with high IU uniquely demonstrated greater defense system activation when impending threat was more uncertain. The association between IU and startle was independent of state anxiety. The present study adds to a growing literature on threat predictability and aversive responding, and suggests IU is associated with abnormal responding in the context of uncertain threat. Copyright © 2015 Elsevier B.V. All rights reserved.

Contrasting effect of prepulse signals on performance of Toxoplasma-infected and Toxoplasma-free subjects in an acoustic reaction times test.

PubMed

Příplatová, Lenka; Sebánková, Blanka; Flegr, Jaroslav

2014-01-01

About 30% of people on Earth have latent toxoplasmosis. Infected subjects do not express any clinical symptoms, however, they carry dormant stages of parasite Toxoplasma for the rest of their life. This form of toxoplasmosis is mostly considered harmless, however, recent studies showed its specific effects on physiology, behaviour and its associations with various diseases, including psychiatric disorders such as schizophrenia. Individuals who suffer from schizophrenia have about 2.7 times higher prevalence of Toxoplasma-seropositivity than controls, which suggests that some traits characteristic of schizophrenic patients, including the sex difference in schizophrenia onset, decrease of grey matter density in specific brain areas and modification of prepulse inhibition of startle reaction could in fact be caused by toxoplasmosis for those patients who are Toxoplasma-seropositive. We measured the effect of prepulse inhibition/facilitation of the startle reaction on reaction times. The students, 170 women and 66 men, were asked to react as quickly as possible to a startling acoustic signal by pressing a computer mouse button. Some of the startling signals were without the prepulse, some were 20 msec. preceded by a short (20 msec.) prepulse signal of lower intensity. Toxoplasma-seropositive subjects had longer reaction times than the controls. Acoustic prepulse shorted the reaction times in all subjects. This effect of prepulse on reaction times was stronger in male subjects and increased with the duration of infection, suggesting that it represented a cumulative effect of latent toxoplasmosis, rather than a fading out after effect of past acute toxoplasmosis. Different sensitivity of Toxoplasma-seropositive and Toxoplasma-seronegative subjects on effect of prepulses on reaction times (the toxoplasmosis-prepulse interaction) suggested, but of course did not prove, that the alternations of prepulse inhibition of startle reaction observed in schizophrenia patients

Immobility and hyperthermia in the tail suspension test: association with the Porsolt test and the reflex startle reaction in 11 inbred mouse strains and the effects of genetic knockout of MAO A.

PubMed

Popova, N K; Tibeikina, M A

2010-06-01

Immobility and hyperthermia induced by unavoidable stress imposed by the tail suspension test (TST) and the acoustic startle reaction were assessed in mice of 11 inbred strains and in Tg8 mice, which have genetic knockout of MAO A. Sharp genotypic differences in immobility were seen, while there was no correlation with the hyperthermic response to the TST. A correlation was found between the extent of immobility in the TST and the startle reaction. Studies of 11 strains of mice revealed a positive correlation between the duration of immobility in the TST and the Porsolt "despair test." Genetic knockout of MAO A, one of the key enzymes in catecholamine and serotonin metabolism in the brain, weakened the startle reaction and TST-induced hyperthermia but had no significant effect on the immobility of Tg8 mice, which provides evidence of differences in the neurochemical regulation of these reactions. These data provide grounds for using the TST as a "dry" Porsolt test and identify TST-induced hyperthermia as a model for reactions to unavoidable stress.

Problems in nonlinear acoustics: Scattering of sound by sound, parametric receiving arrays, nonlinear effects in asymmetric sound beams and pulsed finite amplitude sound beams

NASA Astrophysics Data System (ADS)

Hamilton, Mark F.

1989-08-01

Four projects are discussed in this annual summary report, all of which involve basic research in nonlinear acoustics: Scattering of Sound by Sound, a theoretical study of two nonconlinear Gaussian beams which interact to produce sum and difference frequency sound; Parametric Receiving Arrays, a theoretical study of parametric reception in a reverberant environment; Nonlinear Effects in Asymmetric Sound Beams, a numerical study of two dimensional finite amplitude sound fields; and Pulsed Finite Amplitude Sound Beams, a numerical time domain solution of the KZK equation.

Azimuthal Traveltime and Amplitude Anomalies of Tropospheric and Thermospheric Acoustic Waves From the Explosive Eruption of the Sakurajima Volcano in Japan

NASA Astrophysics Data System (ADS)

Watada, S.; Arai, N.; Murayama, T.; Iwakuni, M.; Nogami, M.; Oi, T.; Imanishi, Y.; Kitagawa, Y.

2010-12-01

With more than 20 microbarometers in a distance range from as small as 4 km to 1100 km, we observed the strongest explosive eruption since 2000 of the Sakurajima volcano, located at the southern end of the Kyushu Island in Japan. An MB2005 at 4-km away from the summit recorded one strong sharp acoustic signal with peak-to-peak amplitude 1200 Pa and duration 4 sec. This nearby microbarogram guarantees that no small eruption occurred with amplitude more than a few tens Pa within a day after this explosive eruption. At the I30H IMS array which is 1000 km away from the volcano, we observed a dispersed pressure wave train with duration 1 min and maximum amplitude 5 Pa and dominant periods 5-10 sec. Array analysis shows a tropospheric propagating infrasound from the azimuth of Sakurajima with an apparent velocity 0.345 km/s. All distant stations are nearly linearly aligned from Sakurajima to the I30H array and their azimuths are 37-65 deg. Within this small azimuth range, we observed a strong azimuthal anisotropy in traveltime and amplitude. The patterns of traveltime anomaly and amplitude are similar, earlier the arrival, larger the amplitude. This implies that these traveltime and amplitude anomalies are wave propagation origin and are likely caused by the wind, not by an asymmetric radiation pattern of the explosion source. More microbarograms including two MB2005s were running in the Honshu Island during the eruption but these records show little infrasound signals with amplitude more than a few Pa. There seems a clear areal boundary where infrasound was observed or not. Another prominent feature of waveforms is the multiple later phases reflected from the troposphere and the thermosphere. The record section of microbarograms recorded at less than 500 km from the volcano reveals nearly-equally time-separated later phases up to 5 bounces. The traveltime curves progressively increases the apparent velocity as the time increases and distance decreases, suggesting

Azimuthal Traveltime and Amplitude Anomalies of Tropospheric and Thermospheric Acoustic Waves From the Explosive Eruption of the Sakurajima Volcano in Japan

NASA Astrophysics Data System (ADS)

Watada, Shingo; Arai, Nobuo; Murayama, Takahiko; Iwakuni, Makiko; Nogami, Mami; Imanishi, Yuichi; Oi, Takuma; Kitagawa, Yuichi

2010-05-01

With more than 20 microbarometers in a distance range from as small as 4 km to 1100 km, we observed the strongest explosive eruption since 2000 of the Sakurajima volcano, located at the southern end of the Kyushu Island in Japan. An MB2005 at 4-km away from the summit recorded one strong sharp acoustic signal with peak-to-peak amplitude 1200 Pa and duration 4 sec. This nearby microbarogram guarantees that no small eruption occurred with amplitude more than a few tens Pa within a day after this explosive eruption. At the I30H IMS array which is 1000 km away from the volcano, we observed a dispersed pressure wave train with duration 1 min and maximum amplitude 5 Pa and dominant periods 5-10 sec. Array analysis shows a tropospheric propagating infrasound from the azimuth of Sakurajima with an apparent velocity 0.345 km/s. All distant stations are nearly linearly aligned from Sakurajima to the I30H array and their azimuths are 37-65 deg. Within this small azimuth range, we observed a strong azimuthal anisotropy in traveltime and amplitude. The patterns of traveltime anomaly and amplitude are similar, earlier the arrival, larger the amplitude. This implies that these traveltime and amplitude anomalies are wave propagation origin and are likely caused by the wind, not by an asymmetric radiation pattern of the explosion source. More microbarograms including two MB2005s were running in the Honshu Island during the eruption but these records show little infrasound signals with amplitude more than a few Pa. There seems a clear areal boundary where infrasound was observed or not. Another prominent feature of waveforms is the multiple later phases reflected from the troposphere and the thermosphere. The record section of microbarograms recorded at less than 500 km from the volcano reveals nearly-equally time-separated later phases up to 5 bounces. The traveltime curves progressively increases the apparent velocity as the time increases and distance decreases, suggesting

Mutations in the human GlyT2 gene define a presynaptic component of human startle disease

PubMed Central

Rees, Mark I.; Harvey, Kirsten; Pearce, Brian R.; Chung, Seo-Kyung; Duguid, Ian C.; Thomas, Philip; Beatty, Sarah; Graham, Gail E.; Armstrong, Linlea; Shiang, Rita; Abbott, Kim J.; Zuberi, Sameer M.; Stephenson, John B.P.; Owen, Michael J.; Tijssen, Marina A.J.; van den Maagdenberg, Arn M.J.M.; Smart, Trevor G.; Supplisson, Stéphane; Harvey, Robert J.

2011-01-01

Hyperekplexia is a human neurological disorder characterized by an excessive startle response and is typically caused by missense and nonsense mutations in the gene encoding the inhibitory glycine receptor (GlyR) α1 subunit (GLRA1)1-3. Genetic heterogeneity has been confirmed in isolated sporadic cases with mutations in other postsynaptic glycinergic proteins including the GlyR β subunit (GLRB)4, gephyrin (GPHN)5 and RhoGEF collybistin (ARHGEF9)6. However, many sporadic patients diagnosed with hyperekplexia do not carry mutations in these genes2-7. Here we reveal that missense, nonsense and frameshift mutations in the presynaptic glycine transporter 2 (GlyT2) gene (SLC6A5)8 also cause hyperekplexia. Patients harbouring mutations in SLC6A5 presented with hypertonia, an exaggerated startle response to tactile or acoustic stimuli, and life-threatening neonatal apnoea episodes. GlyT2 mutations result in defective subcellular localisation and/or decreased glycine uptake, with selected mutations affecting predicted glycine and Na+ binding sites. Our results demonstrate that SLC6A5 is a major gene for hyperekplexia and define the first neurological disorder linked to mutations in a Na+/Cl−-dependent transporter for a classical fast neurotransmitter. By analogy, we suggest that in other human disorders where defects in postsynaptic receptors have been identified, similar symptoms could result from defects in the cognate presynaptic neurotransmitter transporter. PMID:16751771

Magneto-acoustic imaging by continuous-wave excitation.

PubMed

Shunqi, Zhang; Zhou, Xiaoqing; Tao, Yin; Zhipeng, Liu

2017-04-01

The electrical characteristics of tissue yield valuable information for early diagnosis of pathological changes. Magneto-acoustic imaging is a functional approach for imaging of electrical conductivity. This study proposes a continuous-wave magneto-acoustic imaging method. A kHz-range continuous signal with an amplitude range of several volts is used to excite the magneto-acoustic signal and improve the signal-to-noise ratio. The magneto-acoustic signal amplitude and phase are measured to locate the acoustic source via lock-in technology. An optimisation algorithm incorporating nonlinear equations is used to reconstruct the magneto-acoustic source distribution based on the measured amplitude and phase at various frequencies. Validation simulations and experiments were performed in pork samples. The experimental and simulation results agreed well. While the excitation current was reduced to 10 mA, the acoustic signal magnitude increased up to 10 -7  Pa. Experimental reconstruction of the pork tissue showed that the image resolution reached mm levels when the excitation signal was in the kHz range. The signal-to-noise ratio of the detected magneto-acoustic signal was improved by more than 25 dB at 5 kHz when compared to classical 1 MHz pulse excitation. The results reported here will aid further research into magneto-acoustic generation mechanisms and internal tissue conductivity imaging.

Thermal Imaging of the Periorbital Regions during the Presentation of an Auditory Startle Stimulus

PubMed Central

Gane, Luke; Power, Sarah; Kushki, Azadeh; Chau, Tom

2011-01-01

Infrared thermal imaging of the inner canthi of the periorbital regions of the face can potentially serve as an input signal modality for an alternative access system for individuals with conditions that preclude speech or voluntary movement, such as total locked-in syndrome. However, it is unknown if the temperature of these regions is affected by the human startle response, as changes in the facial temperature of the periorbital regions manifested during the startle response could generate false positives in a thermography-based access system. This study presents an examination of the temperature characteristics of the periorbital regions of 11 able-bodied adult participants before and after a 102 dB auditory startle stimulus. The results indicate that the startle response has no substantial effect on the mean temperature of the periorbital regions. This indicates that thermography-based access solutions would be insensitive to startle reactions in their user, an important advantage over other modalities being considered in the context of access solutions for individuals with a severe motor disability. PMID:22073302

Anticipation of public speaking in virtual reality reveals a relationship between trait social anxiety and startle reactivity.

PubMed

Cornwell, Brian R; Johnson, Linda; Berardi, Luciano; Grillon, Christian

2006-04-01

Startle reflex modification has become valuable to the study of fear and anxiety, but few studies have explored startle reactivity in socially threatening situations. Healthy participants ranging in trait social anxiety entered virtual reality (VR) that simulates standing center-stage in front of an audience to anticipate giving a speech and count backward. We measured startle and autonomic reactivity during anticipation of both tasks inside VR after a single baseline recording outside VR. Trait social anxiety, but not general trait anxiety, was positively correlated with startle before entering VR and most clearly during speech anticipation inside VR. Speech anticipation inside VR also elicited stronger physiologic responses relative to anticipation of counting. Under social-evaluative threat, startle reactivity showed robust relationships with fear of negative evaluation, a central aspect of social anxiety and clinical social phobia. Context-specific startle modification may be an endophenotype for subtypes of pathological anxiety.

Spatial hearing ability of the pigmented Guinea pig (Cavia porcellus): Minimum audible angle and spatial release from masking in azimuth.

PubMed

Greene, Nathaniel T; Anbuhl, Kelsey L; Ferber, Alexander T; DeGuzman, Marisa; Allen, Paul D; Tollin, Daniel J

2018-08-01

Despite the common use of guinea pigs in investigations of the neural mechanisms of binaural and spatial hearing, their behavioral capabilities in spatial hearing tasks have surprisingly not been thoroughly investigated. To begin to fill this void, we tested the spatial hearing of adult male guinea pigs in several experiments using a paradigm based on the prepulse inhibition (PPI) of the acoustic startle response. In the first experiment, we presented continuous broadband noise from one speaker location and switched to a second speaker location (the "prepulse") along the azimuth prior to presenting a brief, ∼110 dB SPL startle-eliciting stimulus. We found that the startle response amplitude was systematically reduced for larger changes in speaker swap angle (i.e., greater PPI), indicating that using the speaker "swap" paradigm is sufficient to assess stimulus detection of spatially separated sounds. In a second set of experiments, we swapped low- and high-pass noise across the midline to estimate their ability to utilize interaural time- and level-difference cues, respectively. The results reveal that guinea pigs can utilize both binaural cues to discriminate azimuthal sound sources. A third set of experiments examined spatial release from masking using a continuous broadband noise masker and a broadband chirp signal, both presented concurrently at various speaker locations. In general, animals displayed an increase in startle amplitude (i.e., lower PPI) when the masker was presented at speaker locations near that of the chirp signal, and reduced startle amplitudes (increased PPI) indicating lower detection thresholds when the noise was presented from more distant speaker locations. In summary, these results indicate that guinea pigs can: 1) discriminate changes in source location within a hemifield as well as across the midline, 2) discriminate sources of low- and high-pass sounds, demonstrating that they can effectively utilize both low-frequency interaural

Forced synchronization and asynchronous quenching in a thermo-acoustic system

NASA Astrophysics Data System (ADS)

Mondal, Sirshendu; Pawar, Samadhan A.; Sujith, Raman

2017-11-01

Forced synchronization, which has been extensively studied in theory and experiments, occurs through two different mechanisms known as phase locking and asynchronous quenching. The latter indicates the suppression of oscillation amplitude. In most practical combustion systems such as gas turbine engines, the main concern is high amplitude pressure oscillations, known as thermo-acoustic instability. Thermo-acoustic instability is undesirable and needs to be suppressed because of its damaging consequences to an engine. In the present study, a systematic experimental investigation of forced synchronization is performed in a prototypical thermo-acoustic system, a Rijke tube, in its limit cycle operation. Further, we show a qualitatively similar behavior using a reduced order model. In the phase locking region, the simultaneous occurrence of synchronization and resonant amplification leads to high amplitude pressure oscillations. However, a reduction in the amplitude of natural oscillations by about 78% of the unforced amplitude is observed when the forcing frequency is far lower than the natural frequency. This shows the possibility of suppression of the oscillation amplitude through asynchronous quenching in thermo-acoustic systems.

Additive Effects of Threat-of-Shock and Picture Valence on Startle Reflex Modulation

PubMed Central

Bublatzky, Florian; Guerra, Pedro M.; Pastor, M. Carmen; Schupp, Harald T.; Vila, Jaime

2013-01-01

The present study examined the effects of sustained anticipatory anxiety on the affective modulation of the eyeblink startle reflex. Towards this end, pleasant, neutral and unpleasant pictures were presented as a continuous stream during alternating threat-of-shock and safety periods, which were cued by colored picture frames. Orbicularis-EMG to auditory startle probes and electrodermal activity were recorded. Previous findings regarding affective picture valence and threat-of-shock modulation were replicated. Of main interest, anticipating aversive events and viewing affective pictures additively modulated defensive activation. Specifically, despite overall potentiated startle blink magnitude in threat-of-shock conditions, the startle reflex remained sensitive to hedonic picture valence. Finally, skin conductance level revealed sustained sympathetic activation throughout the entire experiment during threat- compared to safety-periods. Overall, defensive activation by physical threat appears to operate independently from reflex modulation by picture media. The present data confirms the importance of simultaneously manipulating phasic-fear and sustained-anxiety in studying both normal and abnormal anxiety. PMID:23342060

Resting heart rate variability and the startle reflex to briefly presented affective pictures.

PubMed

Ruiz-Padial, Elisabeth; Thayer, Julian F

2014-12-01

We have previously shown that persons with low HRV showed potentiated startle responses to neutral stimuli. In the present study we replicated our prior findings and extended them to examine the effects of HRV on the startle magnitude to pictures that were presented outside of conscious awareness. A total of 85 male and female students were stratified via median split on their resting HRV. They were presented pictures for 6 s or for 30 ms. Results indicated that the high HRV group showed the context appropriate startle magnitude increase to unpleasant foreground. The low HRV group showed startle magnitude increase from pleasant to neutral pictures but no difference between the neutral and unpleasant pictures. This pattern of results was similar for the 30 ms and the 6 s conditions. These results suggest that having high HRV may allow persons to more efficiently process emotional stimuli and to better recognize threat and safety signals. Copyright © 2014 Elsevier B.V. All rights reserved.

Changes in the magnitude of the eyeblink startle response during habituation of sexual arousal.

PubMed

Koukounas, E; Over, R

2000-06-01

Modulation of the startle response was used to examine emotional processing of sexual stimulation across trials within a session. Eyeblink startle was elicited by a probe (burst of intense white noise) presented intermittently while men were viewing an erotic film segment. Repeated display of the film segment resulted in a progressive decrease in sexual arousal. Habituation of sexual arousal was accompanied by a reduction over trials in the extent the men felt absorbed when viewing the erotic stimulus and by an increase over trials in the magnitude of the eyeblink startle response. Replacing the familiar stimulus by a novel erotic stimulus increased in sexual arousal and absorption and reduced startle (novelty effect), while dishabituation was evident for all three response measures when the familiar stimulus was reintroduced. This pattern of results indicates that with repeated presentation an erotic stimulus is experienced not only as less sexually arousing but also as less appetitive and absorbing. The question of whether habituation of sexual arousal is mediated by changes in attentional and affective processing over trials is discussed, as are clinical contexts in which eyeblink startle can be used in studying aspects of sexual functioning.

Empirically based comparisons of the reliability and validity of common quantification approaches for eyeblink startle potentiation in humans

PubMed Central

Bradford, Daniel E.; Starr, Mark J.; Shackman, Alexander J.

2015-01-01

Abstract Startle potentiation is a well‐validated translational measure of negative affect. Startle potentiation is widely used in clinical and affective science, and there are multiple approaches for its quantification. The three most commonly used approaches quantify startle potentiation as the increase in startle response from a neutral to threat condition based on (1) raw potentiation, (2) standardized potentiation, or (3) percent‐change potentiation. These three quantification approaches may yield qualitatively different conclusions about effects of independent variables (IVs) on affect when within‐ or between‐group differences exist for startle response in the neutral condition. Accordingly, we directly compared these quantification approaches in a shock‐threat task using four IVs known to influence startle response in the no‐threat condition: probe intensity, time (i.e., habituation), alcohol administration, and individual differences in general startle reactivity measured at baseline. We confirmed the expected effects of time, alcohol, and general startle reactivity on affect using self‐reported fear/anxiety as a criterion. The percent‐change approach displayed apparent artifact across all four IVs, which raises substantial concerns about its validity. Both raw and standardized potentiation approaches were stable across probe intensity and time, which supports their validity. However, only raw potentiation displayed effects that were consistent with a priori specifications and/or the self‐report criterion for the effects of alcohol and general startle reactivity. Supplemental analyses of reliability and validity for each approach provided additional evidence in support of raw potentiation. PMID:26372120

Generation of thermo-acoustic waves from pulsed solar/IR radiation

NASA Astrophysics Data System (ADS)

Rahman, Aowabin

Acoustic waves could potentially be used in a wide range of engineering applications; however, the high energy consumption in generating acoustic waves from electrical energy and the cost associated with the process limit the use of acoustic waves in industrial processes. Acoustic waves converted from solar radiation provide a feasible way of obtaining acoustic energy, without relying on conventional nonrenewable energy sources. One of the goals of this thesis project was to experimentally study the conversion of thermal to acoustic energy using pulsed radiation. The experiments were categorized into "indoor" and "outdoor" experiments, each with a separate experimental setup. The indoor experiments used an IR heater to power the thermo-acoustic lasers and were primarily aimed at studying the effect of various experimental parameters on the amplitude of sound waves in the low frequency range (below 130 Hz). The IR radiation was modulated externally using a chopper wheel and then impinged on a porous solid, which was housed inside a thermo-acoustic (TA) converter. A microphone located at a certain distance from the porous solid inside the TA converter detected the acoustic signals. The "outdoor" experiments, which were targeted at TA conversion at comparatively higher frequencies (in 200 Hz-3 kHz range) used solar energy to power the thermo-acoustic laser. The amplitudes (in RMS) of thermo-acoustic signals obtained in experiments using IR heater as radiation source were in the 80-100 dB range. The frequency of acoustic waves corresponded to the frequency of interceptions of the radiation beam by the chopper. The amplitudes of acoustic waves were influenced by several factors, including the chopping frequency, magnitude of radiation flux, type of porous material, length of porous material, external heating of the TA converter housing, location of microphone within the air column, and design of the TA converter. The time-dependent profile of the thermo-acoustic signals

Vibration amplitude and induced temperature limitation of high power air-borne ultrasonic transducers.

PubMed

Saffar, Saber; Abdullah, Amir

2014-01-01

The acoustic impedances of matching layers, their internal loss and vibration amplitude are the most important and influential parameters in the performance of high power airborne ultrasonic transducers. In this paper, the optimum acoustic impedances of the transducer matching layers were determined by using a genetic algorithm, the powerful tool for optimizating domain. The analytical results showed that the vibration amplitude increases significantly for low acoustic impedance matching layers. This enhancement is maximum and approximately 200 times higher for the last matching layer where it has the same interface with the air than the vibration amplitude of the source, lead zirconate titanate-pizo electric while transferring the 1 kW is desirable. This large amplitude increases both mechanical failure and temperature of the matching layers due to the internal loss of the matching layers. It has analytically shown that the temperature in last matching layer with having the maximum vibration amplitude is high enough to melt or burn the matching layers. To verify suggested approach, the effect of the amplitude of vibration on the induced temperature has been investigated experimentally. The experimental results displayed good agreement with the theoretical predictions. Copyright © 2013 Elsevier B.V. All rights reserved.

Acoustic Measurement Of Periodic Motion Of Levitated Object

NASA Technical Reports Server (NTRS)

Watkins, John L.; Barmatz, Martin B.

1992-01-01

Some internal vibrations, oscillations in position, and rotations of acoustically levitated object measured by use of microphone already installed in typical levitation chamber for tuning chamber to resonance and monitoring operation. Levitating acoustic signal modulated by object motion of lower frequency. Amplitude modulation detected and analyzed spectrally to determine amplitudes and frequencies of motions.

Psychometric properties of startle and corrugator response in NPU, Affective Picture Viewing, and Resting State tasks

PubMed Central

Kaye, Jesse T.; Bradford, Daniel E.; Curtin, John J.

2016-01-01

The current study provides a comprehensive evaluation of critical psychometric properties of commonly used psychophysiology laboratory tasks/measures within the NIMH RDoC. Participants (N = 128) completed the No Shock, Predictable Shock, Unpredictable Shock (NPU) task, Affective Picture Viewing task, and Resting State task at two study visits separated by one week. We examined potentiation/modulation scores in NPU (predictable or unpredictable shock vs. no shock) and Affective Picture Viewing tasks (pleasant or unpleasant vs. neutral pictures) for startle and corrugator responses with two commonly used quantification methods. We quantified startle potentiation/modulation scores with raw and standardized responses. We quantified corrugator potentiation/modulation in the time and frequency domains. We quantified general startle reactivity in the Resting State Task as the mean raw startle response during the task. For these three tasks, two measures, and two quantification methods we evaluated effect size robustness and stability, internal consistency (i.e., split-half reliability), and one-week temporal stability. The psychometric properties of startle potentiation in the NPU task were good but concerns were noted for corrugator potentiation in this task. Some concerns also were noted for the psychometric properties of both startle and corrugator modulation in the Affective Picture Viewing task, in particular for pleasant picture modulation. Psychometric properties of general startle reactivity in the Resting State task were good. Some salient differences in the psychometric properties of the NPU and Affective Picture Viewing tasks were observed within and across quantification methods. PMID:27167717

Transmission acoustic microscopy investigation

NASA Astrophysics Data System (ADS)

Maev, Roman; Kolosov, Oleg; Levin, Vadim; Lobkis, Oleg

The nature of acoustic contrast, i.e. the connection of the amplitude and phase of the output signal of the acoustic microscope with the local values of the acoustic parameters of the sample (density, elasticity, viscosity) is a central problem of acoustic microscopy. A considerable number of studies have been devoted to the formation of the output signal of the reflection scanning acoustic microscope. For the transmission acoustic microscope (TAM) this problem has remained almost unstudied. Experimental investigation of the confocal system of the TAM was carried out on an independently manufactured laboratory mockup of the TAM with the working frequency of the 420 MHz. Acoustic lenses with the radius of curvature of about 500 microns and aperture angle of 45 deg were polished out in the end faces of two cylindrical sound conductors made from Al2O3 single crystals with an axis parallel to the axis C of the crystal (the length of the sound conductor is 20 mm; diameter, 6 mm). At the end faces of the sound conductor, opposite to the lenses, CdS transducers with a diameter of 2 mm were disposed. The electric channel of the TAM provided a possibility for registering the amplitude of the microscope output signal in the case of the dynamic range of the 50 dB.

Acoustic detection of pneumothorax

NASA Astrophysics Data System (ADS)

Mansy, Hansen A.; Royston, Thomas J.; Balk, Robert A.; Sandler, Richard H.

2003-04-01

This study aims at investigating the feasibility of using low-frequency (<2000 Hz) acoustic methods for medical diagnosis. Several candidate methods of pneumothorax detection were tested in dogs. In the first approach, broadband acoustic signals were introduced into the trachea during end-expiration and transmitted waves were measured at the chest surface. Pneumothorax was found to consistently decrease pulmonary acoustic transmission in the 200-1200-Hz frequency band, while less change was observed at lower frequencies (p<0.0001). The ratio of acoustic energy between low (<220 Hz) and mid (550-770 Hz) frequency bands was significantly different in the control (healthy) and pneumothorax states (p<0.0001). The second approach measured breath sounds in the absence of an external acoustic input. Pneumothorax was found to be associated with a preferential reduction of sound amplitude in the 200- to 700-Hz range, and a decrease of sound amplitude variation (in the 300 to 600-Hz band) during the respiration cycle (p<0.01 for each). Finally, chest percussion was implemented. Pneumothorax changed the frequency and decay rate of percussive sounds. These results imply that certain medical conditions may be reliably detected using appropriate acoustic measurements and analysis. [Work supported by NIH/NHLBI #R44HL61108.

Hypnotizability, hypnosis and prepulse inhibition of the startle reflex in healthy women: an ERP analysis.

PubMed

De Pascalis, Vilfredo; Russo, Emanuela

2013-01-01

A working model of the neurophysiology of hypnosis suggests that highly hypnotizable individuals (HHs) have more effective frontal attentional systems implementing control, monitoring performance, and inhibiting unwanted stimuli from conscious awareness, than low hypnotizable individuals (LHs). Recent studies, using prepulse inhibition (PPI) of the auditory startle reflex (ASR), suggest that HHs, in the waking condition, may show reduced sensory gating although they may selectively attend and disattend different stimuli. Using a within subject design and a strict subject selection procedure, in waking and hypnosis conditions we tested whether HHs compared to LHs showed a significantly lower inhibition of the ASR and startle-related brain activity in both time and intracerebral source localization domains. HHs, as compared to LH participants, exhibited (a) longer latency of the eyeblink startle reflex, (b) reduced N100 responses to startle stimuli, and (c) higher PPI of eyeblink startle and of the P200 and P300 waves. Hypnosis yielded smaller N100 waves to startle stimuli and greater PPI of this component than in the waking condition. sLORETA analysis revealed that, for the N100 (107 msec) elicited during startle trials, HHs had a smaller activation in the left parietal lobe (BA2/40) than LHs. Auditory pulses of pulse-with prepulse trials in HHs yielded less activity of the P300 (280 msec) wave than LHs, in the cingulate and posterior cingulate gyrus (BA23/31). The present results, on the whole, are in the opposite direction to PPI findings on hypnotizability previously reported in the literature. These results provide support to the neuropsychophysiological model that HHs have more effective sensory integration and gating (or filtering) of irrelevant stimuli than LHs.

Effects of acute exposure of permethrin in adult and developing Sprague-Dawley rats on acoustic startle response and brain and plasma concentrations.

PubMed

Williams, Michael T; Gutierrez, Arnold; Vorhees, Charles V

2018-06-08

Permethrin is a Type I (non-cyano) pyrethroid that induces tremors at high concentrations and increases acoustic startle responses (ASR) in adult rodents, however its effects in young rats have been investigated to a limited extent. ASR and tremor were assessed in adult and postnatal day (P)15 Sprague-Dawley rats at oral doses of 60, 90, or 120 mg/kg over an 8 h period. Permethrin increased ASR in adults, regardless of dose, and 20% of the high-dose rats showed tremor at later time points. For the P15 rats all doses induced tremor at all time points, and ASR was increased at 2 h in the 90 and 120 mg/kg groups with a trend in the 60 mg/kg group compared with controls. The 60 mg/kg group showed increased ASR at 4 and 6 h, whereas the 90 mg/kg group showed no differences from the controls at these times. The 120 mg/kg group showed decreased ASR from 4-8 h post-treatment. P15 and adult rats both showed plasma and brain cis- and trans-permethrin increases after dosing. After the same dose of permethrin, P15 rats had greater cis- and trans-permethrin in brain and plasma compared with adults. P15 rats had an increased tremor response compared with adults even at comparable brain permethrin concentrations. For ASR, P15 rats responded sooner and showed a biphasic pattern ranging from increased to decreased response as a function of dose and time, unlike adults that only showed increases. Overall, young rats showed greater effects from permethrin compared with adults.

Nicotine blocks apomorphine-induced disruption of prepulse inhibition of the acoustic startle in rats: possible involvement of central nicotinic α7 receptors

PubMed Central

Suemaru, Katsuya; Yasuda, Kayo; Umeda, Kenta; Araki, Hiroaki; Shibata, Kazuhiko; Choshi, Tominari; Hibino, Satoshi; Gomita, Yutaka

2004-01-01

Nicotine has been reported to normalize deficits in auditory sensory gating in the cases of schizophrenia, suggesting an involvement of nicotinic acetylcholine receptors in attentional abnormalities. However, the mechanism remains unclear. The present study investigated the effects of nicotine on the disruption of prepulse inhibition (PPI) of the acoustic startle response induced by apomorphine or phencyclidine in rats. Over the dose range tested, nicotine (0.05–1 mg kg−1, s.c.) did not disrupt PPI. Neither methyllycaconitine (0.5–5 mg kg−1, s.c.), an α7 nicotinic receptor antagonist, nor dihydro-β-erythroidine (0.5–2 mg kg−1, s.c.), an α4β2 nicotinic receptor antagonist, had any effect on PPI. Nicotine (0.01–0.2 mg kg−1, s.c.) dose-dependently reversed the disruption of PPI induced by apomorphine (1 mg kg−1, s.c.), but had no effect on the disruption of PPI induced by phencyclidine (2 mg kg−1, s.c.). The reversal of apomorphine-induced PPI disruption by nicotine (0.2 mg kg−1) was eliminated by mecamylamine (1 mg kg−1, i.p.), but not by hexamethonium (10 mg kg−1, i.p.), indicating the involvement of central nicotinic receptors. The antagonistic action of nicotine on apomorphine-induced PPI disruption was dose-dependently blocked by methyllycaconitine (1 and 2 mg kg−1, s.c.). However, dihydro-β-erythroidine (1 and 2 mg kg−1, s.c.) had no effect. These results suggest that nicotine reverses the disruption of apomorphine-induced PPI through central α7 nicotinic receptors. PMID:15197106

Differential effects of perinatal exposure to antidepressants on learning and memory, acoustic startle, anxiety, and open-field activity in Sprague-Dawley rats.

PubMed

Sprowles, Jenna L N; Hufgard, Jillian R; Gutierrez, Arnold; Bailey, Rebecca A; Jablonski, Sarah A; Williams, Michael T; Vorhees, Charles V

2017-10-01

Most antidepressants inhibit monoamine reuptake. Selective serotonin (5-HT) reuptake inhibitors (SSRIs) act on the 5-HT transporter (SERT) whereas norepinephrine-dopamine reuptake inhibitors (NDRIs) act on the norepinephrine and dopamine transporters. Epidemiological reports link SSRI use during pregnancy to an increased prevalence of autism spectrum disorder (ASD). We previously showed that perinatal exposure to the SSRI citalopram (CIT) results in rodent offspring that exhibit a number of behaviors consistent with an ASD-like phenotype. The present study examined the effect of perinatal exposure to CIT (at a lower dose), another SSRI, fluoxetine (FLX), and an NDRI, bupropion (BUP). Gravid Sprague-Dawley rats were subcutaneously injected twice per day (6h apart) with 5mg/kg CIT, 5mg/kg FLX, 15mg/kg BUP, or saline (SAL) from embryonic day (E) 6-21, and directly to the pups from postnatal day (P) 1-20. As adults, one male/female from each litter was given one of a series of tests. Both SSRI-exposed groups showed spatial learning deficits in Morris and radial water mazes, increased marble burying, increased acoustic startle, hypoactivity, and attenuated activity to the stimulating effect of the NMDA-R antagonist MK-801. The BUP-exposed group showed a reduction in elevated zero-maze quadrant entries and increased stimulated open-field activity following (+)-amphetamine challenge. These results reinforce concern about the use of antidepressants during pregnancy and highlight how the two classes of drugs produce different constellations of effects with more effects associated with the SSRIs. Further investigation into how antidepressants alter brain development leading to enduring adverse neurobehavioral effects is warranted. Copyright © 2017 ISDN. Published by Elsevier Ltd. All rights reserved.

Acoustic myography as an indicator of force during sustained contractions of a small hand muscle.

PubMed

Goldenberg, M S; Yack, H J; Cerny, F J; Burton, H W

1991-01-01

To test the hypothesis that muscle sound amplitudes would remain constant during sustained submaximal isometric contractions, we recorded acoustic myograms from the abductor digiti minimi muscle in 12 subjects at 15, 25, 50, and 75% of a maximum voluntary contraction (MVC). Muscle sounds were detected with an omni-directional electret microphone encased in closed-cell foam and attached to the skin over the muscle. Acoustic amplitudes from the middle and end of the sustained contractions were compared with the amplitudes from the beginning of contractions to determine whether acoustic amplitudes varied in magnitude as force remained constant. Physiological tremor was eliminated from the acoustic signal by use of a Fourier truncation at 14 Hz. The amplitudes of the acoustic signal at a contraction intensity of 75% MVC remained constant, reflecting force production over time. At 50% MVC, the root-mean-square amplitude decreased from the beginning to the end of the contraction (P less than 0.05). Acoustic amplitudes increased over time at 15 and 25% MVC and were significantly higher at the end of the contractions than at the beginning (P less than 0.05). Alterations in the acoustic amplitude, which reflect changes in the lateral vibrations of the muscle, may be indicative of the different recruitment strategies used to maintain force during sustained isometric contractions.

The relation between symptoms of bulimia nervosa and obsessive-compulsive disorder: a startle investigation.

PubMed

Altman, Sarah E; Campbell, Miranda L; Nelson, Brady D; Faust, Julianne P; Shankman, Stewart A

2013-11-01

Bulimia nervosa (BN) and obsessive-compulsive disorder (OCD) co-occur at greater rates than chance and may have shared mechanisms of dysfunction. One of these proposed mechanisms is a hyper-responsive aversive system as indicated by heightened startle response to aversive stimuli. The present study examined this hypothesis using 2 types of aversive stimuli: disorder specific (e.g., high-caloric food pictures for BN, contamination pictures for OCD) and nondisorder specific (e.g., knife). Temporal parameters of aversive responding were also examined by assessing startle response in anticipation of and following picture presentation. The sample consisted of 114 undergraduate women selected to have a broad range of BN and/or OCD symptomatology. OCD symptoms were associated with increased startle potentiation during the anticipation and presentation of contamination pictures, and BN symptoms were associated with increased startle potentiation during disorder-related contamination pictures (e.g., sink, toilet). BN symptoms were also associated with increased startle potentiation during and following the presentation of food pictures (though the former effect was only a trend). Additionally, the interaction of BN and OCD symptoms was associated with elevated startle responding during the presentation of contamination and threat stimuli. Overall, the present study provides evidence that BN and OCD symptoms are associated with heightened aversive responding to disorder-specific stimuli, and comorbid BN and OCD symptoms are associated with heightened aversive responding across disorder-specific and nonspecific aversive stimuli. Clinical and theoretical implications are discussed. PsycINFO Database Record (c) 2013 APA, all rights reserved.

Rate of initial recovery and subsequent radar monitoring performance following a simulated emergency involving startle.

DOT National Transportation Integrated Search

1983-09-01

The present study employed auditory startle to simulate the principal components (unexpectedness, fear, and physiological arousal) that are common to many types of sudden emergencies and compared performance recovery following startle with recovery f...

Distinct Contributions of Median Raphe Nucleus to Contextual Fear Conditioning and Fear-Potentiated Startle

PubMed Central

Silva, R. C. B.; Cruz, A. P. M.; Avanzi, V.; Landeira-Fernandez, J.; Brandão, M. L.

2002-01-01

Ascending 5-HT projections from the median raphe nucleus (MRN), probably to the hippocampus, are implicated in the acquisition of contextual fear (background stimuli), as assessed by freezing behavior. Foreground cues like light, used as a conditioned stimulus (CS) in classical fear conditioning, also cause freezing through thalamic transmission to the amygdala. As the MRN projects to the hippocampus and amygdala, the role of this raphe nucleus in fear conditioning to explicit cues remains to be explained. Here we analyzed the behavior of rats with MRN electrolytic lesions in a contextual conditioning situation and in a fear-potentiated startle procedure. The animals received MRN electrolytic lesions either before or on the day after two consecutive training sessions in which they were submitted to 10 conditioning trials, each in an experimental chamber (same context) where they. received foot-shocks (0.6 mA, 1 sec) paired to a 4-sec light CS. Seven to ten days later, the animals were submitted to testing sessions for assessing conditioned fear when they were placed for five shocks, and the duration of contextual freezing was recorded. The animals were then submitted to a fear-potentiated startle in response to a 4-sec light-CS, followed by white noise (100 dB, 50 ms). Control rats (sham) tested in the same context showed more freezing than did rats with pre- or post-training MRN lesions. Startle was clearly potentiated in the presence of light CS in the sham-lesioned animals. Whereas pretraining lesions reduced both freezing and fear-potentiated startle, the post-training lesions reduced only freezing to context, without changing the fear-potentiated startle. In a second experiment, neurotoxic lesions of the MRN with local injections of N-methyl-D-aspartate or the activation of 5-HT1A somatodendritic auto-receptors of the MRN by microinjections of the 5-HT1A receptor agonist 8-hydroxy- 2-(di-n-propylamino)tetralin (8-OH-DPAT) before the training sessions also

Negative Self-Focused Cognitions Mediate the Effect of Trait Social Anxiety on State Anxiety

PubMed Central

Schulz, Stefan M.; Alpers, Georg W.; Hofmann, Stefan G.

2008-01-01

The cognitive model of social anxiety predicts that negative self-focused cognitions increase anxiety when anticipating social threat. To test this prediction, 36 individuals were asked to anticipate and perform a public speaking task. During anticipation, negative self-focused cognitions or relaxation were experimentally induced while self-reported anxiety, autonomic arousal (heart rate, heart rate variability, skin conductance level), and acoustic eye-blink startle response were assessed. As predicted, negative self-focused cognitions mediated the effects of trait social anxiety on self-reported anxiety and heart rate variability during negative anticipation. Furthermore, trait social anxiety predicted increased startle amplitudes. These findings support a central assumption of the cognitive model of social anxiety. PMID:18321469

Arbitrary amplitude fast electron-acoustic solitons in three-electron component space plasmas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mbuli, L. N.; Maharaj, S. K.; Department of Physics, University of the Western Cape

We examine the characteristics of fast electron-acoustic solitons in a four-component unmagnetised plasma model consisting of cool, warm, and hot electrons, and cool ions. We retain the inertia and pressure for all the plasma species by assuming adiabatic fluid behaviour for all the species. By using the Sagdeev pseudo-potential technique, the allowable Mach number ranges for fast electron-acoustic solitary waves are explored and discussed. It is found that the cool and warm electron number densities determine the polarity switch of the fast electron-acoustic solitons which are limited by either the occurrence of fast electron-acoustic double layers or warm and hotmore » electron number density becoming unreal. For the first time in the study of solitons, we report on the coexistence of fast electron-acoustic solitons, in addition to the regular fast electron-acoustic solitons and double layers in our multi-species plasma model. Our results are applied to the generation of broadband electrostatic noise in the dayside auroral region.« less

Emotion modulation of the startle reflex in essential tremor: Blunted reactivity to unpleasant and pleasant pictures.

PubMed

Lafo, Jacob A; Mikos, Ania; Mangal, Paul C; Scott, Bonnie M; Trifilio, Erin; Okun, Michael S; Bowers, Dawn

2017-01-01

Essential tremor is a highly prevalent movement disorder characterized by kinetic tremor and mild cognitive-executive changes. These features are commonly attributed to abnormal cerebellar changes, resulting in disruption of cerebellar-thalamo-cortical networks. Less attention has been paid to alterations in basic emotion processing in essential tremor, despite known cerebellar-limbic interconnectivity. In the current study, we tested the hypothesis that a psychophysiologic index of emotional reactivity, the emotion modulated startle reflex, would be muted in individuals with essential tremor relative to controls. Participants included 19 essential tremor patients and 18 controls, who viewed standard sets of unpleasant, pleasant, and neutral pictures for six seconds each. During picture viewing, white noise bursts were binaurally presented to elicit startle eyeblinks measured over the orbicularis oculi. Consistent with past literature, controls' startle eyeblink responses were modulated according to picture valence (unpleasant > neutral > pleasant). In essential tremor participants, startle eyeblinks were not modulated by emotion. This modulation failure was not due to medication effects, nor was it due to abnormal appraisal of emotional picture content. Neuroanatomically, it remains unclear whether diminished startle modulation in essential tremor is secondary to aberrant cerebellar input to the amygdala, which is involved in priming the startle response in emotional contexts, or due to more direct disruption between the cerebellum and brainstem startle circuitry. If the former is correct, these findings may be the first to reveal dysregulation of emotional networks in essential tremor. Copyright © 2016 Elsevier Ltd. All rights reserved.

Hypnotizability, Hypnosis and Prepulse Inhibition of the Startle Reflex in Healthy Women: An ERP Analysis

PubMed Central

De Pascalis, Vilfredo; Russo, Emanuela

2013-01-01

A working model of the neurophysiology of hypnosis suggests that highly hypnotizable individuals (HHs) have more effective frontal attentional systems implementing control, monitoring performance, and inhibiting unwanted stimuli from conscious awareness, than low hypnotizable individuals (LHs). Recent studies, using prepulse inhibition (PPI) of the auditory startle reflex (ASR), suggest that HHs, in the waking condition, may show reduced sensory gating although they may selectively attend and disattend different stimuli. Using a within subject design and a strict subject selection procedure, in waking and hypnosis conditions we tested whether HHs compared to LHs showed a significantly lower inhibition of the ASR and startle-related brain activity in both time and intracerebral source localization domains. HHs, as compared to LH participants, exhibited (a) longer latency of the eyeblink startle reflex, (b) reduced N100 responses to startle stimuli, and (c) higher PPI of eyeblink startle and of the P200 and P300 waves. Hypnosis yielded smaller N100 waves to startle stimuli and greater PPI of this component than in the waking condition. sLORETA analysis revealed that, for the N100 (107 msec) elicited during startle trials, HHs had a smaller activation in the left parietal lobe (BA2/40) than LHs. Auditory pulses of pulse-with prepulse trials in HHs yielded less activity of the P300 (280 msec) wave than LHs, in the cingulate and posterior cingulate gyrus (BA23/31). The present results, on the whole, are in the opposite direction to PPI findings on hypnotizability previously reported in the literature. These results provide support to the neuropsychophysiological model that HHs have more effective sensory integration and gating (or filtering) of irrelevant stimuli than LHs. PMID:24278150

Controlling Sample Rotation in Acoustic Levitation

NASA Technical Reports Server (NTRS)

Barmatz, M. B.; Stoneburner, J. D.

1985-01-01

Rotation of acoustically levitated object stopped or controlled according to phase-shift monitoring and control concept. Principle applies to square-cross-section levitation chamber with two perpendicular acoustic drivers operating at same frequency. Phase difference between X and Y acoustic excitation measured at one corner by measuring variation of acoustic amplitude sensed by microphone. Phase of driver adjusted to value that produces no rotation or controlled rotation of levitated object.

Time reversal focusing of high amplitude sound in a reverberation chamber.

PubMed

Willardson, Matthew L; Anderson, Brian E; Young, Sarah M; Denison, Michael H; Patchett, Brian D

2018-02-01

Time reversal (TR) is a signal processing technique that can be used for intentional sound focusing. While it has been studied in room acoustics, the application of TR to produce a high amplitude focus of sound in a room has not yet been explored. The purpose of this study is to create a virtual source of spherical waves with TR that are of sufficient intensity to study nonlinear acoustic propagation. A parameterization study of deconvolution, one-bit, clipping, and decay compensation TR methods is performed to optimize high amplitude focusing and temporal signal focus quality. Of all TR methods studied, clipping is shown to produce the highest amplitude focal signal. An experiment utilizing eight horn loudspeakers in a reverberation chamber is done with the clipping TR method. A peak focal amplitude of 9.05 kPa (173.1 dB peak re 20 μPa) is achieved. Results from this experiment indicate that this high amplitude focusing is a nonlinear process.

Problems in nonlinear acoustics: Pulsed finite amplitude sound beams, nonlinear acoustic wave propagation in a liquid layer, nonlinear effects in asymmetric cylindrical sound beams, effects of absorption on the interaction of sound beams, and parametric receiving arrays

NASA Astrophysics Data System (ADS)

Hamilton, Mark F.

1990-12-01

This report discusses five projects all of which involve basic theoretical research in nonlinear acoustics: (1) pulsed finite amplitude sound beams are studied with a recently developed time domain computer algorithm that solves the KZK nonlinear parabolic wave equation; (2) nonlinear acoustic wave propagation in a liquid layer is a study of harmonic generation and acoustic soliton information in a liquid between a rigid and a free surface; (3) nonlinear effects in asymmetric cylindrical sound beams is a study of source asymmetries and scattering of sound by sound at high intensity; (4) effects of absorption on the interaction of sound beams is a completed study of the role of absorption in second harmonic generation and scattering of sound by sound; and (5) parametric receiving arrays is a completed study of parametric reception in a reverberant environment.

Acoustic emission intrusion detector

DOEpatents

Carver, Donald W.; Whittaker, Jerry W.

1980-01-01

An intrusion detector is provided for detecting a forcible entry into a secured structure while minimizing false alarms. The detector uses a piezoelectric crystal transducer to sense acoustic emissions. The transducer output is amplified by a selectable gain amplifier to control the sensitivity. The rectified output of the amplifier is applied to a Schmitt trigger circuit having a preselected threshold level to provide amplitude discrimination. Timing circuitry is provided which is activated by successive pulses from the Schmitt trigger which lie within a selected time frame for frequency discrimination. Detected signals having proper amplitude and frequency trigger an alarm within the first complete cycle time of a detected acoustical disturbance signal.

Round window closure affects cochlear responses to suprathreshold stimuli.

PubMed

Cai, Qunfeng; Whitcomb, Carolyn; Eggleston, Jessica; Sun, Wei; Salvi, Richard; Hu, Bo Hua

2013-12-01

The round window acts as a vent for releasing inner ear pressure and facilitating basilar membrane vibration. Loss of this venting function affects cochlear function, which leads to hearing impairment. In an effort to identify functional changes that might be used in clinical diagnosis of round window atresia, the current investigation was designed to examine how the cochlea responds to suprathreshold stimuli following round window closure. Prospective, controlled, animal study. A rat model of round window occlusion (RWO) was established. With this model, the thresholds of auditory brainstem responses (ABR) and the input/output (IO) functions of distortion product otoacoustic emissions (DPOAEs) and acoustic startle responses were examined. Round window closure caused a mild shift in the thresholds of the auditory brainstem response (13.5 ± 9.1 dB). It also reduced the amplitudes of the distortion product otoacoustic emissions and the slope of the input/output functions. This peripheral change was accompanied by a significant reduction in the amplitude, but not the threshold, of the acoustic startle reflex, a motor response to suprathreshold sounds. In addition to causing mild increase in the threshold of the auditory brainstem response, round window occlusion reduced the slopes of both distortion product otoacoustic emissions and startle reflex input/output functions. These changes differ from those observed for typical conductive or sensory hearing loss, and could be present in patients with round window atresia. However, future clinical observations in patients are needed to confirm these findings. Copyright © 2013 The American Laryngological, Rhinological and Otological Society, Inc.

Experimental study of outdoor propagation of spherically speading periodic acoustic waves of finite amplitude

NASA Technical Reports Server (NTRS)

Theobald, M. A.

1977-01-01

The outdoor propagation of spherically spreading sound waves of finite amplitude was investigated. The main purpose of the experiments was to determine the extent to which the outdoor environment, mainly random inhomogeneity of the medium, affects finite amplitude propagation. Periodic sources with fundamental frequencies in the range 6 to 8 kHz and source levels SPLlm from 140 to 149 dB were used. The sources were an array of 7 to 10 horn drivers and a siren. The propagation path was vertical and parallel to an 85 m tower, whose elevator carried the traveling microphone. The general conclusions drawn from the experimental results were as follows. The inhomogeneities caused significant fluctuations in the instantaneous acoustic signal, but with sufficient time averaging of the measured harmonic levels, the results were comparable to results expected for propagation in a quiet medium. Propagation data for the fundamental of the siren approached within 1 dB of the weak shock saturation levels. Extra attenuation on the order of 8 dB was observed. The measurements generally confirmed the predictions of several theoretical models. The maximum propagation distance was 36 m. The narrowbeam arrays were much weaker sources. Nonlinear propagation distortion was produced, but the maximum value of extra attenuation measured was 1.5 dB. The maximum propagation distance was 76 m. The behavior of the asymetric waveforms received in one experiment qualitatively suggested that beam type diffraction effects were present. The role of diffraction of high intensity sound waves in radiation from a single horn was briefly investigated.

In Your Face: Startle to Emotional Facial Expressions Depends on Face Direction.

PubMed

Åsli, Ole; Michalsen, Henriette; Øvervoll, Morten

2017-01-01

Although faces are often included in the broad category of emotional visual stimuli, the affective impact of different facial expressions is not well documented. The present experiment investigated startle electromyographic responses to pictures of neutral, happy, angry, and fearful facial expressions, with a frontal face direction (directed) and at a 45° angle to the left (averted). Results showed that emotional facial expressions interact with face direction to produce startle potentiation: Greater responses were found for angry expressions, compared with fear and neutrality, with directed faces. When faces were averted, fear and neutrality produced larger responses compared with anger and happiness. These results are in line with the notion that startle is potentiated to stimuli signaling threat. That is, a forward directed angry face may signal a threat toward the observer, and a fearful face directed to the side may signal a possible threat in the environment.

Acoustically levitated dancing drops: Self-excited oscillation to chaotic shedding.

PubMed

Lin, Po-Cheng; I, Lin

2016-02-01

We experimentally demonstrate self-excited oscillation and shedding of millimeter-sized water drops, acoustically levitated in a single-node standing waves cavity, by decreasing the steady acoustic wave intensity below a threshold. The perturbation of the acoustic field by drop motion is a possible source for providing an effective negative damping for sustaining the growing amplitude of the self-excited motion. Its further interplay with surface tension, drop inertia, gravity and acoustic intensities, select various self-excited modes for different size of drops and acoustic intensity. The large drop exhibits quasiperiodic motion from a vertical mode and a zonal mode with growing coupling, as oscillation amplitudes grow, until falling on the floor. For small drops, chaotic oscillations constituted by several broadened sectorial modes and corresponding zonal modes are self-excited. The growing oscillation amplitude leads to droplet shedding from the edges of highly stretched lobes, where surface tension no longer holds the rapid expanding flow.

Acoustically levitated dancing drops: Self-excited oscillation to chaotic shedding

NASA Astrophysics Data System (ADS)

Lin, Po-Cheng; I, Lin

2016-02-01

We experimentally demonstrate self-excited oscillation and shedding of millimeter-sized water drops, acoustically levitated in a single-node standing waves cavity, by decreasing the steady acoustic wave intensity below a threshold. The perturbation of the acoustic field by drop motion is a possible source for providing an effective negative damping for sustaining the growing amplitude of the self-excited motion. Its further interplay with surface tension, drop inertia, gravity and acoustic intensities, select various self-excited modes for different size of drops and acoustic intensity. The large drop exhibits quasiperiodic motion from a vertical mode and a zonal mode with growing coupling, as oscillation amplitudes grow, until falling on the floor. For small drops, chaotic oscillations constituted by several broadened sectorial modes and corresponding zonal modes are self-excited. The growing oscillation amplitude leads to droplet shedding from the edges of highly stretched lobes, where surface tension no longer holds the rapid expanding flow.

Behaviour of a Premixed Flame Subjected to Acoustic Oscillations

PubMed Central

Qureshi, Shafiq R.; Khan, Waqar A.; Prosser, Robert

2013-01-01

In this paper, a one dimensional premixed laminar methane flame is subjected to acoustic oscillations and studied. The purpose of this analysis is to investigate the effects of acoustic perturbations on the reaction rates of different species, with a view to their respective contribution to thermoacoustic instabilities. Acoustically transparent non reflecting boundary conditions are employed. The flame response has been studied with acoustic waves of different frequencies and amplitudes. The integral values of the reaction rates, the burning velocities and the heat release of the acoustically perturbed flame are compared with the unperturbed case. We found that the flame's sensitivity to acoustic perturbations is greatest when the wavelength is comparable to the flame thickness. Even in this case, the perturbations are stable with time. We conclude that acoustic fields acting on the chemistry do not contribute significantly to the emergence of large amplitude pressure oscillations. PMID:24376501

Responses to amplitude modulated infrared stimuli in the guinea pig inferior colliculus

NASA Astrophysics Data System (ADS)

Richter, Claus-Peter; Young, Hunter

2013-03-01

Responses of units in the central nucleus of the inferior colliculus of the guinea pig were recorded with tungsten electrodes. The set of data presented here is limited to high stimulus levels. The effect of changing the modulation frequency and the modulation depth was explored for acoustic and laser stimuli. The selected units responded to sinusoidal amplitude modulated (AM) tones, AM trains of clicks, and AM trains of laser pulses with a modulation of their spike discharge. At modulation frequencies of 20 Hz, some units tended to respond with 40 Hz to the acoustic stimuli, but only at 20 Hz for the trains of laser pulses. For all modes of stimulation the responses revealed a dominant response to the first cycle of the modulation, with decreasing number of action potential during successive cycles. While amplitude modulated tone bursts and amplitude modulated trains of acoustic clicks showed similar patterns, the response to trains of laser pulses was different.

Investigation of a central nucleus of the amygdala/dorsal raphe nucleus serotonergic circuit implicated in fear-potentiated startle.

PubMed

Spannuth, B M; Hale, M W; Evans, A K; Lukkes, J L; Campeau, S; Lowry, C A

2011-04-14

Serotonergic systems are thought to play an important role in control of motor activity and emotional states. We used a fear-potentiated startle paradigm to investigate the effects of a motor-eliciting stimulus in the presence or absence of induction of an acute fear state on serotonergic neurons in the dorsal raphe nucleus (DR) and cells in subdivisions of the central amygdaloid nucleus (CE), a structure that plays an important role in fear responses, using induction of the protein product of the immediate-early gene, c-Fos. In Experiment 1 we investigated the effects of fear conditioning training, by training rats to associate a light cue (conditioned stimulus, CS; 1000 lx, 2 s) with foot shock (0.5 s, 0.5 mA) in a single session. In Experiment 2 rats were given two training sessions identical to Experiment 1 on days 1 and 2, then tested in one of four conditions on day 3: (1) placement in the training context without exposure to either the CS or acoustic startle (AS), (2) exposure to 10 trials of the 2 s CS, (3) exposure to 40 110 dB AS trials, or (4) exposure to 40 110 dB AS trials with 10 of the trials preceded by and co-terminating with the CS. All treatments were conducted during a 20 min session. Fear conditioning training, by itself, increased c-Fos expression in multiple subdivisions of the CE and throughout the DR. In contrast, fear-potentiated startle selectively increased c-Fos expression in the medial subdivision of the CE and in serotonergic neurons in the dorsal part of the dorsal raphe nucleus (DRD). These data are consistent with previous studies demonstrating that fear-related stimuli selectively activate DRD serotonergic neurons. Further studies of this mesolimbocortical serotonergic system could have important implications for understanding mechanisms underlying vulnerability to stress-related psychiatric disorders, including anxiety and affective disorders. Copyright © 2011 IBRO. Published by Elsevier Ltd. All rights reserved.

Investigation of a central nucleus of the amygdala/dorsal raphe nucleus serotonergic circuit implicated in fear-potentiated startle

PubMed Central

Spannuth, Benjamin M.; Hale, Matthew W.; Evans, Andrew K.; Lukkes, Jodi L.; Campeau, Serge; Lowry, Christopher A.

2011-01-01

Serotonergic systems are thought to play an important role in control of motor activity and emotional states. We used a fear-potentiated startle paradigm to investigate the effects of a motor-eliciting stimulus in the presence or absence of induction of an acute fear state on serotonergic neurons in the dorsal raphe nucleus (DR) and cells in subdivisions of the central amygdaloid nucleus (CE), a structure that plays an important role in fear responses, using induction of the protein product of the immediate-early gene, c-fos. In Experiment 1 we investigated the effects of fear conditioning training, by training rats to associate a light cue (conditioned stimulus, CS; 1000 lx, 2 sec) with foot shock (0.5 s, 0.5 mA) in a single session. In Experiment 2 rats were given two training sessions identical to Experiment 1 on days 1 and 2, then tested in one of four conditions on day 3: 1) placement in the training context without exposure to either the CS or acoustic startle (AS), 2) exposure to 10 trials of the 2 s CS, 3) exposure to 40 110 dB AS trials, or 4) exposure to 40 110 dB AS trials with 10 of the trials preceded by and co-terminating with the CS. All treatments were conducted during a 20 min session. Fear conditioning training, by itself, increased c-Fos expression in multiple subdivisions of the CE and throughout the DR. In contrast, fear-potentiated startle selectively increased c-Fos expression in the medial subdivision of the CE and in serotonergic neurons in the dorsal part of the dorsal raphe nucleus (DRD). These data are consistent with previous studies demonstrating that fear-related stimuli selectively activate DRD serotonergic neurons. Further studies of this mesolimbocortical serotonergic system could have important implications for understanding mechanisms underlying vulnerability to stress-related psychiatric disorders, including anxiety and affective disorders. PMID:21277950

Spatiotemporal reconstruction of auditory steady-state responses to acoustic amplitude modulations: Potential sources beyond the auditory pathway.

PubMed

Farahani, Ehsan Darestani; Goossens, Tine; Wouters, Jan; van Wieringen, Astrid

2017-03-01

Investigating the neural generators of auditory steady-state responses (ASSRs), i.e., auditory evoked brain responses, with a wide range of screening and diagnostic applications, has been the focus of various studies for many years. Most of these studies employed a priori assumptions regarding the number and location of neural generators. The aim of this study is to reconstruct ASSR sources with minimal assumptions in order to gain in-depth insight into the number and location of brain regions that are activated in response to low- as well as high-frequency acoustically amplitude modulated signals. In order to reconstruct ASSR sources, we applied independent component analysis with subsequent equivalent dipole modeling to single-subject EEG data (young adults, 20-30 years of age). These data were based on white noise stimuli, amplitude modulated at 4, 20, 40, or 80Hz. The independent components that exhibited a significant ASSR were clustered among all participants by means of a probabilistic clustering method based on a Gaussian mixture model. Results suggest that a widely distributed network of sources, located in cortical as well as subcortical regions, is active in response to 4, 20, 40, and 80Hz amplitude modulated noises. Some of these sources are located beyond the central auditory pathway. Comparison of brain sources in response to different modulation frequencies suggested that the identified brain sources in the brainstem, the left and the right auditory cortex show a higher responsiveness to 40Hz than to the other modulation frequencies. Copyright © 2017 Elsevier Inc. All rights reserved.

Prepulse inhibition of the startle reflex and its attentional modulation in the human S-ketamine and N,N-dimethyltryptamine (DMT) models of psychosis.

PubMed

Heekeren, K; Neukirch, A; Daumann, J; Stoll, M; Obradovic, M; Kovar, K-A; Geyer, M A; Gouzoulis-Mayfrank, E

2007-05-01

Patients with schizophrenia exhibit diminished prepulse inhibition (PPI) of the acoustic startle reflex and deficits in the attentional modulation of PPI. Pharmacological challenges with hallucinogens are used as models for psychosis in both humans and animals. Remarkably, in contrast to the findings in schizophrenic patients and in animal hallucinogen models of psychosis, previous studies with healthy volunteers demonstrated increased levels of PPI after administration of low to moderate doses of either the antiglutamatergic hallucinogen ketamine or the serotonergic hallucinogen psilocybin. The aim of the present study was to investigate the influence of moderate and high doses of the serotonergic hallucinogen N,N-dimethyltryptamine (DMT) and the N-methyl-D-aspartate antagonist S-ketamine on PPI and its attentional modulation in humans. Fifteen healthy volunteers were included in a double-blind cross-over study with two doses of DMT and S-ketamine. Effects on PPI and its attentional modulation were investigated. Nine subjects completed both experimental days with the two doses of both drugs. S-ketamine increased PPI in both dosages, whereas DMT had no significant effects on PPI. S-ketamine decreased and DMT tended to decrease startle magnitude. There were no significant effects of either drug on the attentional modulation of PPI. In human experimental hallucinogen psychoses, and even with high, clearly psychotogenic doses of DMT or S-ketamine, healthy subjects failed to exhibit the predicted attenuation of PPI. In contrast, PPI was augmented and the startle magnitude was decreased after S-ketamine. These data point to important differences between human hallucinogen models and both animal hallucinogen models of psychosis and naturally occurring schizophrenia.

A Cyfip2-Dependent Excitatory Interneuron Pathway Establishes the Innate Startle Threshold.

PubMed

Marsden, Kurt C; Jain, Roshan A; Wolman, Marc A; Echeverry, Fabio A; Nelson, Jessica C; Hayer, Katharina E; Miltenberg, Ben; Pereda, Alberto E; Granato, Michael

2018-04-17

Sensory experiences dynamically modify whether animals respond to a given stimulus, but it is unclear how innate behavioral thresholds are established. Here, we identify molecular and circuit-level mechanisms underlying the innate threshold of the zebrafish startle response. From a forward genetic screen, we isolated five mutant lines with reduced innate startle thresholds. Using whole-genome sequencing, we identify the causative mutation for one line to be in the fragile X mental retardation protein (FMRP)-interacting protein cyfip2. We show that cyfip2 acts independently of FMRP and that reactivation of cyfip2 restores the baseline threshold after phenotype onset. Finally, we show that cyfip2 regulates the innate startle threshold by reducing neural activity in a small group of excitatory hindbrain interneurons. Thus, we identify a selective set of genes critical to establishing an innate behavioral threshold and uncover a circuit-level role for cyfip2 in this process. Copyright © 2018 The Author(s). Published by Elsevier Inc. All rights reserved.

Fast and singular muscle responses initiate the startle response of Pantodon buchholzi (Osteoglossomorpha).

PubMed

Starosciak, A K; Kalola, R P; Perkins, K P; Riley, J A; Saidel, W M

2008-01-01

The startle response of Pantodon buchholzi, the African butterfly fish, is a complete or incomplete ballistic jump resulting from abduction of the pectoral fins. This study analyzed the neuromuscular basis for such a jump by recording in vivo electromyograms (emgs) from the muscles of abduction, the muscularis abductor superficialis (MAS) and the muscularis abductor profundus (MAP). The motor neurons innervating the MAS muscle were localized by retrograde transport of biocytin. The latency between stimulus and the evoked emg in the MAS was less than 5 ms; the latency of the MAP was about 6.5 ms. A single emg was recorded per jump. High speed video demonstrated that onset of a startle movement began within 10 ms of the onset of fin abduction. The emg associated with this movement is short (<2 ms) and followed by a variably-shaped, slower and smaller potential of 10-30 ms duration. The brief period between stimulus and startle response of Pantodon suggests a Mauthner neuron-related response, only with the behavior occurring in the vertical plane. The MAS may act only in a startle response, whereas the MAP might have a role in other behaviors. Elicited jumping habituates after a single trial. Electrophysiological evidence is presented indicating that the innervating motor neurons are suppressed for seconds following a stimulus. The neurons innervating the MAS are located at the medullary-spinal cord junction and possess an average radius of approximately 17.9 mum. These fish have been historically described as 'fresh water' flying fish. As a single emg occurs per startle response, repetitive pectoral activity generating flying cannot be supported. Pantodon 'flight' is ballistic. Copyright 2007 S. Karger AG, Basel.

Validation of an auditory startle response system using chemicals or parametric modulation as positive controls.

PubMed

Marable, Brian R; Maurissen, Jacques P J

2004-01-01

Neurotoxicity regulatory guidelines mandate that automated test systems be validated using chemicals. However, in some cases, chemicals may not necessarily be needed to prove test system validity. To examine this issue, two independent experiments were conducted to validate an automated auditory startle response (ASR) system. In Experiment 1, we used adult (PND 63) and weanling (PND 22) Sprague-Dawley rats (10/sex/dose) to determine the effect of either d-amphetamine (4.0 or 8.0 mg/kg) or clonidine (0.4 or 0.8 mg/kg) on the ASR peak amplitude (ASR PA). The startle response of each rat to a short burst of white noise (120 dB SPL) was recorded over 50 consecutive trials. The ASR PA was significantly decreased (by clonidine) and increased (by d-amphetamine) compared to controls in PND 63 rats. In PND 22 rats, the response to clonidine was similar to adults, but d-amphetamine effects were not significant. Neither drug affected the rate of the decrease in ASR PA over time (habituation). In Experiment 2, PND 31 Sprague-Dawley rats (8/sex) were presented with 150 trials consisting of either white noise bursts of variable intensity (70-120 dB SPL in 10 dB increments, presented in random order) or null (0 dB SPL) trials. Statistically significant sex- and intensity-dependent differences were detected in the ASR PA. These results suggest that in some cases, parametric modulation may be an alternative to using chemicals for test system validation.

FAST satellite observations of large-amplitude solitary structures

NASA Astrophysics Data System (ADS)

Ergun, R. E.; Carlson, C. W.; McFadden, J. P.; Mozer, F. S.; Delory, G. T.; Peria, W.; Chaston, C. C.; Temerin, M.; Roth, I.; Muschietti, L.; Elphic, R.; Strangeway, R.; Pfaff, R.; Cattell, C. A.; Klumpar, D.; Shelley, E.; Peterson, W.; Moebius, E.; Kistler, L.

We report observations of “fast solitary waves” that are ubiquitous in downward current regions of the mid-altitude auroral zone. The single-period structures have large amplitudes (up to 2.5 V/m), travel much faster than the ion acoustic speed, carry substantial potentials (up to ∼100 Volts), and are associated with strong modulations of energetic electron fluxes. The amplitude and speed of the structures distinguishes them from ion-acoustic solitary waves or weak double layers. The electromagnetic signature appears to be that of an positive charge (electron hole) traveling anti-earthward. We present evidence that the structures are in or near regions of magnetic-field-aligned electric fields and propose that these nonlinear structures play a key role in supporting parallel electric fields in the downward current region of the auroral zone.

Involvement of noradrenergic and corticoid receptors in the consolidation of the lasting anxiogenic effects of predator stress.

PubMed

Adamec, R; Muir, C; Grimes, M; Pearcey, K

2007-05-16

The roles of beta-NER (beta-noradrenergic receptor), GR (glucocorticoid) and mineral corticoid receptors (MR) in the consolidation of anxiogenic effects of predator stress were studied. One minute after predator stress, different groups of rats were injected (ip) with vehicle, propranolol (beta-NER blocker, 5 and 10 mg/kg), mifepristone (RU486, GR blocker, 20 mg/kg), spironolactone (MR blocker, 50 mg/kg), propranolol (5 mg/kg) plus RU486 (20 mg/kg) or the anxiolytic, chloradiazepoxide (CPZ, 10 mg/kg). One week later, rodent anxiety was assessed in elevated plus maze, hole board, light/dark box, social interaction and acoustic startle. Considering all tests except startle, propranolol dose dependently blocked consolidation of lasting anxiogenic effects of predator stress in all tests. GR receptor block alone was ineffective. However, GR block in combination with an ineffective dose of propranolol did blocked consolidation of predator stress effects in all tests, suggesting a synergism between beta-NER and GR. Surprisingly, MR block prevented consolidation of anxiogenic effects in all tests except the light/dark box. CPZ post stress was ineffective against the anxiogenic impact of predator stress. Study of startle was complicated by the fact that anxiogenic effects of stress on startle amplitude manifested as both an increase and a decrease in startle amplitude. Suppression of startle occurred in stressed plus vehicle injected groups handled three times prior to predator stress. In contrast, stressed plus vehicle rats handled five times prior to predator stress showed increases in startle, as did all predator stressed only groups. Mechanisms of consolidation of the different startle responses appear to differ. CPZ post stress blocked startle suppression but not enhancement of startle. Propranolol post stress had no effect on either suppression or enhancement of startle. GR block alone post stress prevented suppression of startle, but not enhancement. In contrast

Supertaster, super reactive: oral sensitivity for bitter taste modulates emotional approach and avoidance behavior in the affective startle paradigm.

PubMed

Herbert, Cornelia; Platte, Petra; Wiemer, Julian; Macht, Michael; Blumenthal, Terry D

2014-08-01

People differ in both their sensitivity for bitter taste and their tendency to respond to emotional stimuli with approach or avoidance. The present study investigated the relationship between these sensitivities in an affective picture paradigm with startle responding. Emotion-induced changes in arousal and attention (pupil modulation), priming of approach and avoidance behavior (startle reflex modulation), and subjective evaluations (ratings) were examined. Sensitivity for bitter taste was assessed with the 6-n-propylthiouracil (PROP)-sensitivity test, which discriminated individuals who were highly sensitive to PROP compared to NaCl (PROP-tasters) and those who were less sensitive or insensitive to the bitter taste of PROP. Neither pupil responses nor picture ratings differed between the two taster groups. The startle eye blink response, however, significantly differentiated PROP-tasters from PROP-insensitive subjects. Facilitated response priming to emotional stimuli emerged in PROP-tasters but not in PROP-insensitive subjects at shorter startle lead intervals (200-300ms between picture onset and startle stimulus onset). At longer lead intervals (3-4.5s between picture onset and startle stimulus onset) affective startle modulation did not differ between the two taster groups. This implies that in PROP-sensitive individuals action tendencies of approach or avoidance are primed immediately after emotional stimulus exposure. These results suggest a link between PROP taste perception and biologically relevant patterns of emotional responding. Direct perception-action links have been proposed to underlie motivational priming effects of the startle reflex, and the present results extend these to the sensory dimension of taste. Copyright © 2014 Elsevier Inc. All rights reserved.

Startle Auditory Stimuli Enhance the Performance of Fast Dynamic Contractions

PubMed Central

Fernandez-Del-Olmo, Miguel; Río-Rodríguez, Dan; Iglesias-Soler, Eliseo; Acero, Rafael M.

2014-01-01

Fast reaction times and the ability to develop a high rate of force development (RFD) are crucial for sports performance. However, little is known regarding the relationship between these parameters. The aim of this study was to investigate the effects of auditory stimuli of different intensities on the performance of a concentric bench-press exercise. Concentric bench-presses were performed by thirteen trained subjects in response to three different conditions: a visual stimulus (VS); a visual stimulus accompanied by a non-startle auditory stimulus (AS); and a visual stimulus accompanied by a startle auditory stimulus (SS). Peak RFD, peak velocity, onset movement, movement duration and electromyography from pectoralis and tricep muscles were recorded. The SS condition induced an increase in the RFD and peak velocity and a reduction in the movement onset and duration, in comparison with the VS and AS condition. The onset activation of the pectoralis and tricep muscles was shorter for the SS than for the VS and AS conditions. These findings point out to specific enhancement effects of loud auditory stimulation on the rate of force development. This is of relevance since startle stimuli could be used to explore neural adaptations to resistance training. PMID:24489967

Nanoliter-droplet acoustic streaming via ultra high frequency surface acoustic waves.

PubMed

Shilton, Richie J; Travagliati, Marco; Beltram, Fabio; Cecchini, Marco

2014-08-06

The relevant length scales in sub-nanometer amplitude surface acoustic wave-driven acoustic streaming are demonstrated. We demonstrate the absence of any physical limitations preventing the downscaling of SAW-driven internal streaming to nanoliter microreactors and beyond by extending SAW microfluidics up to operating frequencies in the GHz range. This method is applied to nanoliter scale fluid mixing. © 2014 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Experimental study of the oscillation of spheres in an acoustic levitator.

PubMed

Andrade, Marco A B; Pérez, Nicolás; Adamowski, Julio C

2014-10-01

The spontaneous oscillation of solid spheres in a single-axis acoustic levitator is experimentally investigated by using a high speed camera to record the position of the levitated sphere as a function of time. The oscillations in the axial and radial directions are systematically studied by changing the sphere density and the acoustic pressure amplitude. In order to interpret the experimental results, a simple model based on a spring-mass system is applied in the analysis of the sphere oscillatory behavior. This model requires the knowledge of the acoustic pressure distribution, which was obtained numerically by using a linear finite element method (FEM). Additionally, the linear acoustic pressure distribution obtained by FEM was compared with that measured with a laser Doppler vibrometer. The comparison between numerical and experimental pressure distributions shows good agreement for low values of pressure amplitude. When the pressure amplitude is increased, the acoustic pressure distribution becomes nonlinear, producing harmonics of the fundamental frequency. The experimental results of the spheres oscillations for low pressure amplitudes are consistent with the results predicted by the simple model based on a spring-mass system.

Contextual startle responses moderate the relation between behavioral inhibition and anxiety in middle childhood.

PubMed

Barker, Tyson V; Reeb-Sutherland, Bethany; Degnan, Kathryn A; Walker, Olga L; Chronis-Tuscano, Andrea; Henderson, Heather A; Pine, Daniel S; Fox, Nathan A

2015-11-01

Behavioral inhibition (BI), a temperament characterized in early childhood by wariness and avoidance of novelty, is a risk factor for anxiety disorders. An enhanced startle response has been observed in adolescents characterized with BI in childhood, particularly when they also manifest concurrent symptoms of anxiety. However, no prior study has examined relations among BI, startle responsivity, and anxiety in a prospective manner. Data for the present study were from a longitudinal study of infant temperament. Maternal reports and observations of BI were assessed at ages 2 and 3. At age 7, participants completed a startle procedure, while electromyography was collected, where participants viewed different colors on a screen that were associated with either the delivery of an aversive stimulus (i.e., puff of air to the larynx; threat cue) or the absence of the aversive stimulus (i.e., safety cue). Parental reports of child anxiety were collected when children were 7 and 9 years of age. Results revealed that startle responses at age 7 moderated the relation between early BI and 9-year anxiety. These findings provide insight into one potential mechanism that may place behaviorally inhibited children at risk for anxiety. © 2015 Society for Psychophysiological Research.

DEVELOPMENTAL THYROID HORMONE INSUFFICIENCY ALTERS THE AMPLITUDE OF THE ACOUSTIC STARTLE RESPONSE IN RATS

EPA Science Inventory

Purpose: The thyroid hormone (TH) system is one of the targets of endocrine disrupting chemicals. Since TH is essential for proper brain development, disruption by exposure to chemicals during development can result in adverse neurological outcomes. Previous studies revealed th...

Ionospheric acoustic and gravity waves associated with midlatitude thunderstorms

DOE PAGES

Lay, Erin H.; Shao, Xuan -Min; Kendrick, Alexander K.; ...

2015-07-30

Acoustic waves with periods of 2 - 4 minutes and gravity waves with periods of 6 - 16 minutes have been detected at ionospheric heights (250-350 km) using GPS Total Electron Content (TEC) measurements. The area disturbed by these waves and the wave amplitudes have been associated with underlying thunderstorm activity. A statistical study comparing NEXRAD radar thunderstorm measurements with ionospheric acoustic and gravity waves in the mid-latitude U.S. Great Plains region was performed for the time period of May - July 2005. An increase of ionospheric acoustic wave disturbed area and amplitude is primarily associated with large thunderstorms (mesoscalemore » convective systems). Ionospheric gravity wave disturbed area and amplitude scale with thunderstorm activity, with even small storms (i.e. individual storm cells) producing an increase of gravity waves.« less

Child maltreatment, callous-unemotional traits, and defensive responding in high-risk children: An investigation of emotion-modulated startle response.

PubMed

Dackis, Melissa N; Rogosch, Fred A; Cicchetti, Dante

2015-11-01

Child maltreatment is associated with disruptions in physiological arousal, emotion regulation, and defensive responses to cues of threat and distress, as well as increased risk for callous unemotional (CU) traits and externalizing behavior. Developmental models of CU traits have focused on biological and genetic risk factors that contribute to hypoarousal and antisocial behavior, but have focused less on environmental influences (Blair, 2004; Daversa, 2010; Hare, Frazell, & Cox, 1978; Krueger, 2000; Shirtcliff et al., 2009; Viding, Fontaine, & McCrory, 2012). The aim of the present investigation was to measure the independent and combined effects of child maltreatment and high CU traits on emotion-modulated startle response in children. Participants consisted of 132 low-income maltreated (n = 60) and nonmaltreated (n = 72) children between 8 and 12 years old who attended a summer camp program. Acoustic startle response (ASR) was elicited in response to a 110-dB 50-ms probe while children viewed a slideshow of pleasant, neutral, and unpleasant IAPS images. Maltreatment status was assessed through examination of Department of Human Services records. CU traits were measured using counselor reports from the Inventory of Callous and Unemotional Traits (Frick, 2004), and conduct problems were measured using counselor and child self-report. We found no significant differences in emotion-modulated startle in the overall sample. However, significant differences in ASR by maltreatment status, maltreatment subtype, and level of CU traits were apparent. Results indicated differential physiological responses for maltreated and nonmaltreated children based on CU traits, including a pathway of hypoarousal for nonmaltreated/high CU children that differed markedly from a more normative physiological trajectory for maltreated/high CU children. Further, we found heightened ASR for emotionally and physically neglected children with high CU and elevated antisocial behavior in these

Child Maltreatment, Callous-Unemotional Traits, and Defensive Responding In High-Risk Children: An Investigation of Emotion-Modulated Startle Response

PubMed Central

Dackis, Melissa N.; Rogosch, Fred A.; Cicchetti, Dante

2015-01-01

Child maltreatment is associated with disruptions in physiological arousal, emotion regulation, and defensive responses to cues of threat and distress, as well as increased risk for callous unemotional (CU) traits and externalizing behavior. Developmental models of callous unemotional (CU) traits have focused on biological and genetic risk factors that contribute to hypoarousal and antisocial behavior, but have focused less on environmental influences (Blair, 2004; Daversa, 2010; Hare, Frazell, & Cox, 1978; Krueger, 2000; Shirtcliff et al., 2009; Viding, Fontaine, & McCrory, 2012). The aim of the present investigation was to measure the independent and combined effects of child maltreatment and high CU trait on emotion-modulated startle (EMS) response in children. Participants consisted of 132 low-income maltreated (n = 60) and nonmaltreated (n = 72) children between 8–12 years old who attended a summer camp program. Acoustic startle response (ASR) was elicited in response to a 110-dB 50-ms probe while children viewed a slideshow of pleasant, neutral, and unpleasant IAPS images. Maltreatment status was assessed through examination of Department of Human Services records. CU traits were measured using counselor reports from the Inventory of Callous and Unemotional Traits (ICU; Frick, 2004), and conduct problems were measured using counselor and child self-report. We found no significant differences in emotion-modulated startle in the overall sample. However, significant differences in ASR by maltreatment status, maltreatment subtype, and level of CU traits were apparent. Results indicated differential physiological responses for maltreated and nonmaltreated children based on CU traits, including a pathway of hypoarousal for nonmaltreated/high CU children that differed markedly from a more normative physiological trajectory for maltreated/high CU children. Further, we found heightened ASR for emotionally and physically neglected children with high CU and elevated

Fear-potentiated startle processing in humans: Parallel fMRI and orbicularis EMG assessment during cue conditioning and extinction.

PubMed

Lindner, Katja; Neubert, Jörg; Pfannmöller, Jörg; Lotze, Martin; Hamm, Alfons O; Wendt, Julia

2015-12-01

Studying neural networks and behavioral indices such as potentiated startle responses during fear conditioning has a long tradition in both animal and human research. However, most of the studies in humans do not link startle potentiation and neural activity during fear acquisition and extinction. Therefore, we examined startle blink responses measured with electromyography (EMG) and brain activity measured with functional MRI simultaneously during differential conditioning. Furthermore, we combined these behavioral fear indices with brain network activity by analyzing the brain activity evoked by the startle probe stimulus presented during conditioned visual threat and safety cues as well as in the absence of visual stimulation. In line with previous research, we found a fear-induced potentiation of the startle blink responses when elicited during a conditioned threat stimulus and a rapid decline of amygdala activity after an initial differentiation of threat and safety cues in early acquisition trials. Increased activation during processing of threat cues was also found in the anterior insula, the anterior cingulate cortex (ACC), and the periaqueductal gray (PAG). More importantly, our results depict an increase of brain activity to probes presented during threatening in comparison to safety cues indicating an involvement of the anterior insula, the ACC, the thalamus, and the PAG in fear-potentiated startle processing during early extinction trials. Our study underlines that parallel assessment of fear-potentiated startle in fMRI paradigms can provide a helpful method to investigate common and distinct processing pathways in humans and animals and, thus, contributes to translational research. Copyright © 2015 Elsevier B.V. All rights reserved.

Asians demonstrate reduced sensitivity to unpredictable threat: a preliminary startle investigation using genetic ancestry in a multiethnic sample.

PubMed

Nelson, Brady D; Bishop, Jeffrey R; Sarapas, Casey; Kittles, Rick A; Shankman, Stewart A

2014-06-01

Research has indicated that individuals of Asian descent, relative to other racial groups, demonstrate reduced emotional responding and lower prevalence rates of several anxiety disorders. It is unclear though whether these group differences extend to biomarkers of anxiety disorders and whether genetic differences play a role. This study compared self-identified Caucasian, Latino, and Asian persons (total N = 174) on startle response during a baseline period and while anticipating unpredictable threat-a putative biomarker for certain anxiety disorders--as well as predictable threat. In addition, the association between genetic ancestry and startle response was examined within each racial group to determine potential genetic influences on responding. For the baseline period, Asian participants exhibited a smaller startle response relative to Caucasian and Latino participants, who did not differ. Within each racial group, genetic ancestry was associated with baseline startle. Furthermore, genetic ancestry mediated racial group differences in baseline startle. For the threat conditions, a Race × Condition interaction indicated that Asian participants exhibited reduced startle potentiation to unpredictable, but not predicable, threat relative to Caucasian and Latino participants, who did not differ. However, genetic ancestry was not associated with threat-potentiated startle in any racial group. This study adds to the growing literature on racial differences in emotional responding and provides preliminary evidence suggesting that genetic ancestry may play an important role. Moreover, reduced sensitivity to unpredictable threat may reflect a mechanism for why individuals of Asian descent are at less risk for particular anxiety disorders relative to other racial groups.

Psychopathy, startle blink modulation, and electrodermal reactivity in twin men

PubMed Central

BENNING, STEPHEN D.; PATRICK, CHRISTOPHER J.; IACONO, WILLIAM G.

2008-01-01

Psychopathy is a personality disorder with interpersonal–emotional and antisocial deviance facets. This study investigated these facets of psychopathy prospectively using normal-range personality traits in a community sample of young adult men who completed a picture-viewing task that included startle blink and skin conductance measures, like tasks used to study psychopathy in incarcerated men. Consistent with prior research, scores on the interpersonal–emotional facet of psychopathy (“fearless dominance”) were associated with deficient fear-potentiated startle. Conversely, scores on the social deviance facet of psychopathy (“impulsive antisociality”) were associated with smaller overall skin conductance magnitudes. Participants high in fearless dominance also exhibited deficient skin conductance magnitudes specifically to aversive pictures. Findings encourage further investigation of psychopathy and its etiology in community samples. PMID:16364071

Acoustic integrated extinction.

PubMed

Norris, Andrew N

2015-05-08

The integrated extinction (IE) is defined as the integral of the scattering cross section as a function of wavelength. Sohl et al. (2007 J. Acoust. Soc. Am. 122 , 3206-3210. (doi:10.1121/1.2801546)) derived an IE expression for acoustic scattering that is causal, i.e. the scattered wavefront in the forward direction arrives later than the incident plane wave in the background medium. The IE formula was based on electromagnetic results, for which scattering is causal by default. Here, we derive a formula for the acoustic IE that is valid for causal and non-causal scattering. The general result is expressed as an integral of the time-dependent forward scattering function. The IE reduces to a finite integral for scatterers with zero long-wavelength monopole and dipole amplitudes. Implications for acoustic cloaking are discussed and a new metric is proposed for broadband acoustic transparency.

Simulation of Acoustics for Ares I Scale Model Acoustic Tests

NASA Technical Reports Server (NTRS)

Putnam, Gabriel; Strutzenberg, Louise L.

2011-01-01

The Ares I Scale Model Acoustics Test (ASMAT) is a series of live-fire tests of scaled rocket motors meant to simulate the conditions of the Ares I launch configuration. These tests have provided a well documented set of high fidelity acoustic measurements useful for validation including data taken over a range of test conditions and containing phenomena like Ignition Over-Pressure and water suppression of acoustics. To take advantage of this data, a digital representation of the ASMAT test setup has been constructed and test firings of the motor have been simulated using the Loci/CHEM computational fluid dynamics software. Results from ASMAT simulations with the rocket in both held down and elevated configurations, as well as with and without water suppression have been compared to acoustic data collected from similar live-fire tests. Results of acoustic comparisons have shown good correlation with the amplitude and temporal shape of pressure features and reasonable spectral accuracy up to approximately 1000 Hz. Major plume and acoustic features have been well captured including the plume shock structure, the igniter pulse transient, and the ignition overpressure.

Dealing With Unexpected Events on the Flight Deck: A Conceptual Model of Startle and Surprise.

PubMed

Landman, Annemarie; Groen, Eric L; van Paassen, M M René; Bronkhorst, Adelbert W; Mulder, Max

2017-12-01

A conceptual model is proposed in order to explain pilot performance in surprising and startling situations. Today's debate around loss of control following in-flight events and the implementation of upset prevention and recovery training has highlighted the importance of pilots' ability to deal with unexpected events. Unexpected events, such as technical malfunctions or automation surprises, potentially induce a "startle factor" that may significantly impair performance. Literature on surprise, startle, resilience, and decision making is reviewed, and findings are combined into a conceptual model. A number of recent flight incident and accident cases are then used to illustrate elements of the model. Pilot perception and actions are conceptualized as being guided by "frames," or mental knowledge structures that were previously learned. Performance issues in unexpected situations can often be traced back to insufficient adaptation of one's frame to the situation. It is argued that such sensemaking or reframing processes are especially vulnerable to issues caused by startle or acute stress. Interventions should focus on (a) increasing the supply and quality of pilot frames (e.g., though practicing a variety of situations), (b) increasing pilot reframing skills (e.g., through the use of unpredictability in training scenarios), and (c) improving pilot metacognitive skills, so that inappropriate automatic responses to startle and surprise can be avoided. The model can be used to explain pilot behavior in accident cases, to design experiments and training simulations, to teach pilots metacognitive skills, and to identify intervention methods.

Startling similarity: Effects of facial self-resemblance and familiarity on the processing of emotional faces

PubMed Central

Larra, Mauro F.; Merz, Martina U.; Schächinger, Hartmut

2017-01-01

Facial self-resemblance has been associated with positive emotional evaluations, but this effect may be biased by self-face familiarity. Here we report two experiments utilizing startle modulation to investigate how the processing of facial expressions of emotion is affected by subtle resemblance to the self as well as to familiar faces. Participants of the first experiment (I) (N = 39) were presented with morphed faces showing happy, neutral, and fearful expressions which were manipulated to resemble either their own or unknown faces. At SOAs of either 300 ms or 3500–4500 ms after picture onset, startle responses were elicited by binaural bursts of white noise (50 ms, 105 dB), and recorded at the orbicularis oculi via EMG. Manual reaction time was measured in a simple emotion discrimination paradigm. Pictures preceding noise bursts by short SOA inhibited startle (prepulse inhibition, PPI). Both affective modulation and PPI of startle in response to emotional faces was altered by physical similarity to the self. As indexed both by relative facilitation of startle and faster manual responses, self-resemblance apparently induced deeper processing of facial affect, particularly in happy faces. Experiment II (N = 54) produced similar findings using morphs of famous faces, yet showed no impact of mere familiarity on PPI effects (or response time, either). The results are discussed with respect to differential (presumably pre-attentive) effects of self-specific vs. familiar information in face processing. PMID:29216226

Ultrasound acoustic energy for microbubble manipulation

NASA Astrophysics Data System (ADS)

Bakhtiari-Nejad, Marjan; Elnahhas, Ahmed; Jung, Sunghwan; Shahab, Shima

2017-04-01

Many bio-medical applications entail the problems of spatially manipulating of bubbles by means of acoustic radiation. The examples are ultrasonic noninvasive-targeted drug delivery and therapeutic applications. This paper investigates the nonlinear coupling between radial pulsations, axisymmetric modes of shape oscillations and translational motion of a single spherical gas bubble in a host liquid, when it is subjected to an acoustic pressure wave field. A mathematical model is developed to account for both small and large amplitudes of bubble oscillations. The coupled system dynamics under various conditions is studied. Specifically, oscillating behaviors of a bubble (e.g. the amplitudes and instability of oscillations) undergoing resonance and off-resonance excitation in low- and high- intensity acoustic fields are studied. Instability of the shape modes of a bubble, which is contributing to form the translational instability, known as dancing motion, is analyzed. Dynamic responses of the bubble exposed to low- and high-intensity acoustic excitation are compared in terms of translational motion and surface shape of the bubble. Acoustic streaming effects caused by radial pulsations of the bubble in the surrounding liquid domain are also reported.

Performance recovery following startle : a laboratory approach to the study of behavioral response to sudden aircraft emergencies.

DOT National Transportation Integrated Search

1988-08-01

This paper deals with the use of response/recovery rate to auditory startle as a laboratory technique for simulating some of the principal aspects of the initial shock phase of sudden emergency situations. It is submitted that auditory startle, with ...

Rotation Control In A Cylindrical Acoustic Levitator

NASA Technical Reports Server (NTRS)

Barmatz, M. B.; Allen, J. L.

1988-01-01

Second driver introduces net circulation around levitated sample. Two transducers produce two sets of equal counterrotating acoustic fields. By appropriate adjustment of amplitudes and phases in two transducers, total acoustic field made to consist of two unequal counterrotating fields, producing net torque on levitated sample.

The startle response and toxicology: Methods, use and interpretation.

EPA Science Inventory

The startle response (SR) is a sensory-evoked motor reflex that has been used successfully in toxicology for decades. Advantages of this procedure include: rapidly objective measurement of a defined neural circuit, measurement of habituation of the response, and a high potential ...

Fourth-order acoustic torque in intense sound fields

NASA Technical Reports Server (NTRS)

Wang, T. G.; Kanber, H.; Olli, E. E.

1978-01-01

The observation of a fourth-order acoustic torque in intense sound fields is reported. The torque was determined by measuring the acoustically induced angular deflection of a polished cylinder suspended by a torsion fiber. This torque was measured in a sound field of amplitude greater than that in which first-order acoustic torque has been observed.

Negative, but not positive emotional images modulate the startle response independent of conscious awareness.

PubMed

Reagh, Zachariah M; Knight, David C

2013-08-01

The emotional response to a threat is influenced by the valence of other stimuli in the environment. This emotional modulation of the threat-elicited response occurs even when negative valence stimuli are not consciously perceived. Relatively little prior research has investigated whether nonconsciously perceived positive valence stimuli modify the response to a threat, and the work that has been completed is in need of additional rigorous testing of stimulus and valence perception. The current study presented images of negative, neutral, and positive valence (1,000 ms and 17 ms durations), followed by a mask. A startle probe (100 dB whitenoise) was presented during 33% of each trial type while eyeblink electromyography (EMG) and skin conductance response (SCR) were measured. During the study, participants rated the emotional content of each image to assess valence perception. Participants accurately classified the valence of 1,000 ms images, but not 17 ms images. Further, participants performed at chance levels on an independent postexperimental forced-choice perception task using 17 ms masked images, indicating they were unable to perceive the valence and content of these images. Greater EMG and SCR were elicited by the startle probe during perceived and unperceived negative images compared to perceived and unperceived positive and neutral images. In addition, perceived, but not unperceived positive images diminished startle responses. The current findings suggest that images of negative valence potentiate the startle response in the absence of conscious stimulus perception. However, the attenuation of the startle response by positive images appears to require perception of the emotional valence of an image. PsycINFO Database Record (c) 2013 APA, all rights reserved.

A numerically efficient damping model for acoustic resonances in microfluidic cavities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hahn, P., E-mail: hahnp@ethz.ch; Dual, J.

Bulk acoustic wave devices are typically operated in a resonant state to achieve enhanced acoustic amplitudes and high acoustofluidic forces for the manipulation of microparticles. Among other loss mechanisms related to the structural parts of acoustofluidic devices, damping in the fluidic cavity is a crucial factor that limits the attainable acoustic amplitudes. In the analytical part of this study, we quantify all relevant loss mechanisms related to the fluid inside acoustofluidic micro-devices. Subsequently, a numerical analysis of the time-harmonic visco-acoustic and thermo-visco-acoustic equations is carried out to verify the analytical results for 2D and 3D examples. The damping results aremore » fitted into the framework of classical linear acoustics to set up a numerically efficient device model. For this purpose, all damping effects are combined into an acoustofluidic loss factor. Since some components of the acoustofluidic loss factor depend on the acoustic mode shape in the fluid cavity, we propose a two-step simulation procedure. In the first step, the loss factors are deduced from the simulated mode shape. Subsequently, a second simulation is invoked, taking all losses into account. Owing to its computational efficiency, the presented numerical device model is of great relevance for the simulation of acoustofluidic particle manipulation by means of acoustic radiation forces or acoustic streaming. For the first time, accurate 3D simulations of realistic micro-devices for the quantitative prediction of pressure amplitudes and the related acoustofluidic forces become feasible.« less

Extraordinary acoustic transmission through annuluses in air and its applications in acoustic beam splitter and concentrator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ge, Yong; Liu, Shu-sen; Yuan, Shou-qi, E-mail: Shouqiy@ujs.edu.cn

We report an extraordinary acoustic transmission through two layer annuluses made of metal cylinders in air both numerically and experimentally. The effect arises from the enhancement and reconstruction of the incident source induced by different Mie-resonance modes of the annuluses. The proposed system takes advantages of the consistency in the waveform between the input and output waves, the high amplitude amplification of output waves, and the easy adjustment of structure. More interestingly, we investigate the applications of the extraordinary acoustic transmission in the acoustic beam splitter and acoustic concentrator. Our finding should have an impact on ultrasonic applications.

Sex-Specific Brain Deficits in Auditory Processing in an Animal Model of Cocaine-Related Schizophrenic Disorders

PubMed Central

Broderick, Patricia A.; Rosenbaum, Taylor

2013-01-01

Cocaine is a psychostimulant in the pharmacological class of drugs called Local Anesthetics. Interestingly, cocaine is the only drug in this class that has a chemical formula comprised of a tropane ring and is, moreover, addictive. The correlation between tropane and addiction is well-studied. Another well-studied correlation is that between psychosis induced by cocaine and that psychosis endogenously present in the schizophrenic patient. Indeed, both of these psychoses exhibit much the same behavioral as well as neurochemical properties across species. Therefore, in order to study the link between schizophrenia and cocaine addiction, we used a behavioral paradigm called Acoustic Startle. We used this acoustic startle paradigm in female versus male Sprague-Dawley animals to discriminate possible sex differences in responses to startle. The startle method operates through auditory pathways in brain via a network of sensorimotor gating processes within auditory cortex, cochlear nuclei, inferior and superior colliculi, pontine reticular nuclei, in addition to mesocorticolimbic brain reward and nigrostriatal motor circuitries. This paper is the first to report sex differences to acoustic stimuli in Sprague-Dawley animals (Rattus norvegicus) although such gender responses to acoustic startle have been reported in humans (Swerdlow et al. 1997 [1]). The startle method monitors pre-pulse inhibition (PPI) as a measure of the loss of sensorimotor gating in the brain's neuronal auditory network; auditory deficiencies can lead to sensory overload and subsequently cognitive dysfunction. Cocaine addicts and schizophrenic patients as well as cocaine treated animals are reported to exhibit symptoms of defective PPI (Geyer et al., 2001 [2]). Key findings are: (a) Cocaine significantly reduced PPI in both sexes. (b) Females were significantly more sensitive than males; reduced PPI was greater in females than in males. (c) Physiological saline had no effect on startle in either sex

Asians Demonstrate Reduced Sensitivity to Unpredictable Threat: A Preliminary Startle Investigation using Genetic Ancestry in a Multi-Ethnic Sample

PubMed Central

Nelson, Brady D.; Bishop, Jeffrey R.; Sarapas, Casey; Kittles, Rick A.; Shankman, Stewart A.

2014-01-01

Research has indicated that individuals of Asian descent, relative to other racial groups, demonstrate reduced emotional responding and lower prevalence rates of several anxiety disorders. It is unclear though whether these group differences extend to biomarkers of anxiety disorders and whether genetic differences play a role. The present study compared self-identified Caucasians, Latinos, and Asians (total N = 174) on startle response during a baseline period and while anticipating unpredictable threat–a putative biomarker for certain anxiety disorders–as well as predictable threat. In addition, the association between genetic ancestry and startle response was examined within each racial group to determine potential genetic influences on responding. For the baseline period, Asian participants exhibited a smaller startle response relative to Caucasian and Latino participants, who did not differ. Within each racial group, genetic ancestry was associated with baseline startle. Furthermore, genetic ancestry mediated racial group differences in baseline startle. For the threat conditions, a Race × Condition interaction indicated that Asian participants exhibited reduced startle potentiation to unpredictable, but not predicable, threat relative to Caucasian and Latino participants, who did not differ. However, genetic ancestry was not associated with threat-potentiated startle in any racial group. The present study adds to the growing literature on racial differences in emotional responding and provides preliminary evidence suggesting that genetic ancestry may play an important role. Moreover, reduced sensitivity to unpredictable threat may reflect a mechanism for why individuals of Asian descent are at less risk for particular anxiety disorders relative to other racial groups. PMID:24708496

Dealing With Unexpected Events on the Flight Deck: A Conceptual Model of Startle and Surprise

PubMed Central

Landman, Annemarie; Groen, Eric L.; van Paassen, M. M. (René); Bronkhorst, Adelbert W.; Mulder, Max

2017-01-01

Objective: A conceptual model is proposed in order to explain pilot performance in surprising and startling situations. Background: Today’s debate around loss of control following in-flight events and the implementation of upset prevention and recovery training has highlighted the importance of pilots’ ability to deal with unexpected events. Unexpected events, such as technical malfunctions or automation surprises, potentially induce a “startle factor” that may significantly impair performance. Method: Literature on surprise, startle, resilience, and decision making is reviewed, and findings are combined into a conceptual model. A number of recent flight incident and accident cases are then used to illustrate elements of the model. Results: Pilot perception and actions are conceptualized as being guided by “frames,” or mental knowledge structures that were previously learned. Performance issues in unexpected situations can often be traced back to insufficient adaptation of one’s frame to the situation. It is argued that such sensemaking or reframing processes are especially vulnerable to issues caused by startle or acute stress. Conclusion: Interventions should focus on (a) increasing the supply and quality of pilot frames (e.g., though practicing a variety of situations), (b) increasing pilot reframing skills (e.g., through the use of unpredictability in training scenarios), and (c) improving pilot metacognitive skills, so that inappropriate automatic responses to startle and surprise can be avoided. Application: The model can be used to explain pilot behavior in accident cases, to design experiments and training simulations, to teach pilots metacognitive skills, and to identify intervention methods. PMID:28777917

Materials of acoustic analysis: sustained vowel versus sentence.

PubMed

Moon, Kyung Ray; Chung, Sung Min; Park, Hae Sang; Kim, Han Su

2012-09-01

Sustained vowel is a widely used material of acoustic analysis. However, vowel phonation does not sufficiently demonstrate sentence-based real-life phonation, and biases may occur depending on the test subjects intent during pronunciation. The purpose of this study was to investigate the differences between the results of acoustic analysis using each material. An individual prospective study. Two hundred two individuals (87 men and 115 women) with normal findings in videostroboscopy were enrolled. Acoustic analysis was done using the speech pattern element acquisition and display program. Fundamental frequency (Fx), amplitude (Ax), contact quotient (Qx), jitter, and shimmer were measured with sustained vowel-based acoustic analysis. Average fundamental frequency (FxM), average amplitude (AxM), average contact quotient (QxM), Fx perturbation (CFx), and amplitude perturbation (CAx) were measured with sentence-based acoustic analysis. Corresponding data of the two methods were compared with each other. SPSS (Statistical Package for the Social Sciences, Version 12.0; SPSS, Inc., Chicago, IL) software was used for statistical analysis. FxM was higher than Fx in men (Fx, 124.45 Hz; FxM, 133.09 Hz; P=0.000). In women, FxM seemed to be lower than Fx, but the results were not statistically significant (Fx, 210.58 Hz; FxM, 208.34 Hz; P=0.065). There was no statistical significance between Ax and AxM in both the groups. QxM was higher than Qx in men and women. Jitter was lower in men, but CFx was lower in women. Both Shimmer and CAx were higher in men. Sustained vowel phonation could not be a complete substitute for real-time phonation in acoustic analysis. Characteristics of acoustic materials should be considered when choosing the material for acoustic analysis and interpreting the results. Copyright © 2012 The Voice Foundation. Published by Mosby, Inc. All rights reserved.

Reducing Thermal Conduction In Acoustic Levitators

NASA Technical Reports Server (NTRS)

Lierke, Ernst G.; Leung, Emily W.; Bhat, Balakrishna T.

1991-01-01

Acoustic transducers containing piezoelectric driving elements made more resistant to heat by reduction of effective thermal-conductance cross sections of metal vibration-transmitting rods in them, according to proposal. Used to levitate small objects acoustically for noncontact processing in furnaces. Reductions in cross sections increase amplitudes of transmitted vibrations and reduce loss of heat from furnaces.

Emotional effects of startling background music during reading news reports: The moderating influence of dispositional BIS and BAS sensitivities.

PubMed

Ravaja, Niklas; Kallinen, Kari

2004-07-01

We examined the moderating influence of dispositional behavioral inhibition system (BIS) and behavioral activation system (BAS) sensitivities on the relationship of startling background music with emotion-related subjective and physiological responses elicited during reading news reports, and with memory performance among 26 adult men and women. Physiological parameters measured were respiratory sinus arrhythmia (RSA), electrodermal activity (EDA), and facial electromyography (EMG). The results showed that, among high BAS individuals, news stories with startling background music were rated as more interesting and elicited higher zygomatic EMG activity and RSA than news stories with non-startling music. Among low BAS individuals, news stories with startling background music were rated as less pleasant and more arousing and prompted higher EDA. No BIS-related effects or effects on memory were found. Startling background music may have adverse (e.g., negative arousal) or beneficial effects (e.g., a positive emotional state and stronger positive engagement) depending on dispositional BAS sensitivity of an individual. Actual or potential applications of this research include the personalization of media presentations when using modern media and communications technologies.

Preliminary analysis of amplitude and phase fluctuations in the JAPE multiple tone data to distances of 500 meters

NASA Technical Reports Server (NTRS)

Rogers, James; Sokolov, Radomir; Hicks, Daniel; Cartwright, Lloyd

1993-01-01

The JAPE short range data provide a good opportunity for studying phase and amplitude fluctuations of acoustic signals in the atmosphere over distances of several hundred meters. Several factors contribute to the usefulness of these data: extensive meteorological measurements were made, controlled sources were used, the data were recorded with a high dynamic range digital system that preserved phase information and a significant number of measurement points were obtained allowing both longitudinal and transverse studies. Further, Michigan Tech, in cooperation with the U.S. Army TARDEC, has developed phase tracking algorithms for studying vehicle acoustic signals. These techniques provide an excellent tool for analyzing the amplitude and phase fluctuations of the JAPE data. The results of studies such as those reported here have application at several levels: the mechanisms of signal amplitude and phase fluctuations in propagating acoustic signals are not well understood nor are the mathematical models highly developed, acoustic arrays depend strongly on signal coherence and signal amplitude stability in order to perform to their design specifications and active noise control implementation in regions considerably removed from the primary and secondary sources depends upon signal amplitude and phase stability. Work reported here is preliminary in nature but it does indicate the utility of the phase tracking and amplitude detection algorithms. The results obtained indicate that the phase fluctuations of the JAPE continuous multiple tone data (simultaneous transmission of 80, 200 and 500 Hz) are in general agreement with existing theories but the amplitude fluctuations are seen to be less well behaved and show less consistency.

Observation of self-excited acoustic vortices in defect-mediated dust acoustic wave turbulence.

PubMed

Tsai, Ya-Yi; I, Lin

2014-07-01

Using the self-excited dust acoustic wave as a platform, we demonstrate experimental observation of self-excited fluctuating acoustic vortex pairs with ± 1 topological charges through spontaneous waveform undulation in defect-mediated turbulence for three-dimensional traveling nonlinear longitudinal waves. The acoustic vortex pair has helical waveforms with opposite chirality around the low-density hole filament pair in xyt space (the xy plane is the plane normal to the wave propagation direction). It is generated through ruptures of sequential crest surfaces and reconnections with their trailing ruptured crest surfaces. The initial rupture is originated from the amplitude reduction induced by the formation of the kinked wave crest strip with strong stretching through the undulation instability. Increasing rupture causes the separation of the acoustic vortex pair after generation. A similar reverse process is followed for the acoustic vortex annihilating with the opposite-charged acoustic vortex from the same or another pair generation.

Relationship between Physiological and Parent-Observed Auditory Over-Responsiveness in Children with Typical Development and Those with Autism Spectrum Disorders

ERIC Educational Resources Information Center

Takahashi, Hidetoshi; Nakahachi, Takayuki; Stickley, Andrew; Ishitobi, Makoto; Kamio, Yoko

2018-01-01

The objective of this study was to investigate relationships between caregiver-reported sensory processing abnormalities, and the physiological index of auditory over-responsiveness evaluated using acoustic startle response measures, in children with autism spectrum disorders and typical development. Mean acoustic startle response magnitudes in…

On resonant coupling of acoustic waves and gravity waves

NASA Astrophysics Data System (ADS)

Millet, Christophe

2017-11-01

Acoustic propagation in the atmosphere is often modeled using modes that are confined within waveguides causing the sound to propagate through multiple paths to the receiver. On the other hand, direct observations in the lower stratosphere show that the gravity wave field is intermittent, and is often dominated by rather well defined large-amplitude wave packets. In the present work, we use normal modes to describe both the gravity wave field and the acoustic field. The gravity wave spectrum is obtained by launching few monochromatic waves whose properties are chosen stochastically to mimic the intermittency. Owing to the disparity of the gravity and acoustic length scales, the interactions between the gravity wave field and each of the acoustic modes can be described using a multiple-scale analysis. The appropriate amplitude evolution equation for the acoustic field involves certain random terms that can be directly related to the gravity wave sources. We will show that the cumulative effect of gravity wave breakings makes the sensitivity of ground-based acoustic signals large, in that small changes in the gravity wave parameterization can create or destroy specific acoustic features.

Elliptical Acoustic Particle Motion in Underwater Waveguides

DTIC Science & Technology

2013-03-27

Folkert, ”Tracking sperm whales with a towed acoustic vector sensor,” J. Acoust. Soc. Am. Volume 128, Issue 5, pp. 2681-2694 (2010). 2 Santos, P...modal amplitudes Bm and Cm are weak functions of frequency and range independent. This holds for any normal mode description of the acoustic field in a...wavelengths. Error in measurement aside, the frequency range relation- ship described by the waveguide invariant holds for any directional component of I

Effects of acoustic noise on the auditory nerve compound action potentials evoked by electric pulse trains.

PubMed

Nourski, Kirill V; Abbas, Paul J; Miller, Charles A; Robinson, Barbara K; Jeng, Fuh-Cherng

2005-04-01

This study investigated the effects of acoustic noise on the auditory nerve compound action potentials in response to electric pulse trains. Subjects were adult guinea pigs, implanted with a minimally invasive electrode to preserve acoustic sensitivity. Electrically evoked compound action potentials (ECAP) were recorded from the auditory nerve trunk in response to electric pulse trains both during and after the presentation of acoustic white noise. Simultaneously presented acoustic noise produced a decrease in ECAP amplitude. The effect of the acoustic masker on the electric probe was greatest at the onset of the acoustic stimulus and it was followed by a partial recovery of the ECAP amplitude. Following cessation of the acoustic noise, ECAP amplitude recovered over a period of approximately 100-200 ms. The effects of the acoustic noise were more prominent at lower electric pulse rates (interpulse intervals of 3 ms and higher). At higher pulse rates, the ECAP adaptation to the electric pulse train alone was larger and the acoustic noise, when presented, produced little additional effect. The observed effects of noise on ECAP were the greatest at high electric stimulus levels and, for a particular electric stimulus level, at high acoustic noise levels.

Simplified Rotation In Acoustic Levitation

NASA Technical Reports Server (NTRS)

Barmatz, M. B.; Gaspar, M. S.; Trinh, E. H.

1989-01-01

New technique based on old discovery used to control orientation of object levitated acoustically in axisymmetric chamber. Method does not require expensive equipment like additional acoustic drivers of precisely adjustable amplitude, phase, and frequency. Reflecting object acts as second source of sound. If reflecting object large enough, close enough to levitated object, or focuses reflected sound sufficiently, Rayleigh torque exerted on levitated object by reflected sound controls orientation of object.

Automated Acoustic Identification of Bats

DTIC Science & Technology

2011-10-01

signals. Other signal sources contribute to the overall acoustic soundscape and interfere with discerning the bat calls from the background signals. In...noises, and the changing soundscape from moving can all exceed at least parts of the signal amplitude of bat calls. The ability to track the trend...results, full-spectrum data also provides an effective voucher for interpretation of the full acoustic soundscape at the time of the recording. Figure

An echolocation model for the restoration of an acoustic image from a single-emission echo

NASA Astrophysics Data System (ADS)

Matsuo, Ikuo; Yano, Masafumi

2004-12-01

Bats can form a fine acoustic image of an object using frequency-modulated echolocation sound. The acoustic image is an impulse response, known as a reflected-intensity distribution, which is composed of amplitude and phase spectra over a range of frequencies. However, bats detect only the amplitude spectrum due to the low-time resolution of their peripheral auditory system, and the frequency range of emission is restricted. It is therefore necessary to restore the acoustic image from limited information. The amplitude spectrum varies with the changes in the configuration of the reflected-intensity distribution, while the phase spectrum varies with the changes in its configuration and location. Here, by introducing some reasonable constraints, a method is proposed for restoring an acoustic image from the echo. The configuration is extrapolated from the amplitude spectrum of the restricted frequency range by using the continuity condition of the amplitude spectrum at the minimum frequency of the emission and the minimum phase condition. The determination of the location requires extracting the amplitude spectra, which vary with its location. For this purpose, the Gaussian chirplets with a carrier frequency compatible with bat emission sweep rates were used. The location is estimated from the temporal changes of the amplitude spectra. .

Acoustic manipulation of oscillating spherical bodies: Emergence of axial negative acoustic radiation force

NASA Astrophysics Data System (ADS)

Rajabi, Majid; Mojahed, Alireza

2016-11-01

In this paper, emergence of negative axial acoustic radiation force on a rigid oscillating spherical body is investigated for acoustic manipulation purposes. The problem of plane acoustic wave scattering from an oscillating spherical body submerged in an ideal acoustic fluid medium is solved. For the case of oscillating direction collinear with the wave propagation wave number vector (desired path), it has been shown that the acoustic radiation force, as a result of nonlinear acoustic wave interaction with bodies can be expressed as a linear function of incident wave field and the oscillation properties of the oscillator (i.e., amplitude and phase of oscillation). The negative (i.e., pulling effects) and positive (i.e., pushing effects) radiation force situations are divided in oscillation complex plane with a specific frequency-dependant straight line. This characteristic line defines the radiation force cancellation state. In order to investigate the stability of the mentioned manipulation strategy, the case of misaligned oscillation of sphere with the wave propagation direction is studied. The proposed methodology may suggest a novel concept of single-beam acoustic handling techniques based on smart carriers.

Modification of caffeine effects on the affect-modulated startle by neuropeptide S receptor gene variation.

PubMed

Domschke, Katharina; Klauke, Benedikt; Winter, Bernward; Gajewska, Agnes; Herrmann, Martin J; Warrings, Bodo; Mühlberger, Andreas; Wosnitza, Katherina; Dlugos, Andrea; Naunin, Swantje; Nienhaus, Kathrin; Fobker, Manfred; Jacob, Christian; Arolt, Volker; Pauli, Paul; Reif, Andreas; Zwanzger, Peter; Deckert, Jürgen

2012-08-01

Both the neuropeptide S (NPS) system and antagonism at the adenosine A2A receptor (e.g., by caffeine) were found to play a crucial role in the mediation of arousal and anxiety/panic in animal and human studies. Furthermore, a complex interaction of the neuropeptide S and the adenosinergic system has been suggested with administration of the adenosine A2A receptor antagonist caffeine downregulating NPS levels (Lage et al., 2006) and attenuating the stimulatory effects of NPS in rodents (Boeck et al., 2010). Thus, in the present study, the impact of the functional neuropeptide S receptor (NPSR) A/T (Asn(107)Ile; rs324981) variant on affect-modulated (neutral, unpleasant, and pleasant IAPS pictures) startle response depending on the administration of 300 mg caffeine citrate was investigated in a sample of 124 (m = 58, f = 66) healthy probands using a double-blind, placebo-controlled design. ANOVA revealed a significant interaction between NPSR genotype, challenge condition, and picture valence. Comparing startle magnitudes upon stimulation with neutral or emotional pictures between the placebo and caffeine condition, in AA/AT non-risk genotype carriers no significant difference was discerned, while TT risk genotype carriers showed a significantly increased startle magnitude in response to neutral stimuli (p = .02) and a significantly decreased startle magnitude in response to unpleasant stimuli (p = .02) in the caffeine condition as compared to the placebo condition. In summary, the present findings - extending previous evidence from rodent studies - for the first time provide support for a complex, non-linear interaction of the neuropeptide S and adenosinergic systems affecting the affect-modulated startle response as an intermediate phenotype of anxiety in humans.

Forebrain-specific CRF overproduction during development is sufficient to induce enduring anxiety and startle abnormalities in adult mice.

PubMed

Toth, Mate; Gresack, Jodi E; Bangasser, Debra A; Plona, Zach; Valentino, Rita J; Flandreau, Elizabeth I; Mansuy, Isabelle M; Merlo-Pich, Emilio; Geyer, Mark A; Risbrough, Victoria B

2014-05-01

Corticotropin releasing factor (CRF) regulates physiological and behavioral responses to stress. Trauma in early life or adulthood is associated with increased CRF in the cerebrospinal fluid and heightened anxiety. Genetic variance in CRF receptors is linked to altered risk for stress disorders. Thus, both heritable differences and environmentally induced changes in CRF neurotransmission across the lifespan may modulate anxiety traits. To test the hypothesis that CRF hypersignaling is sufficient to modify anxiety-related phenotypes (avoidance, startle, and conditioned fear), we induced transient forebrain-specific overexpression of CRF (CRFOE) in mice (1) during development to model early-life stress, (2) in adulthood to model adult-onset stress, or (3) across the entire postnatal lifespan to model heritable increases in CRF signaling. The consequences of these manipulations on CRF peptide levels and behavioral responses were examined in adulthood. We found that transient CRFOE during development decreased startle habituation and prepulse inhibition, and increased avoidance (particularly in females) recapitulating the behavioral effects of lifetime CRFOE despite lower CRF peptide levels at testing. In contrast, CRFOE limited to adulthood reduced contextual fear learning in females and increased startle reactivity in males but did not change avoidance or startle plasticity. These findings suggest that forebrain CRFOE limited to development is sufficient to induce enduring alterations in startle plasticity and anxiety, while forebrain CRFOE during adulthood results in a different phenotype profile. These findings suggest that startle circuits are particularly sensitive to forebrain CRFOE, and that the impact of CRFOE may be dependent on the time of exposure.

Anxiety and Depression Symptom Dimensions Demonstrate Unique Relationships with the Startle Reflex in Anticipation of Unpredictable Threat in 8 to 14 Year-Old Girls

PubMed Central

Nelson, Brady D.; Hajcak, Greg

2016-01-01

There is growing evidence that heightened sensitivity to unpredictability is a core mechanism of anxiety disorders. In adults, multiple anxiety disorders have been associated with a heightened startle reflex in anticipation of unpredictable threat. Child and adolescent anxiety has been linked to an increased startle reflex across baseline, safety, and threat conditions. However, it is unclear whether anxiety in youth is related to the startle reflex as a function of threat predictability. In a sample of 90 8 to 14 year-old girls, the present study examined the association between anxiety symptom dimensions and startle potentiation during a no, predictable, and unpredictable threat task. Depression symptom dimensions were also examined given their high comorbidity with anxiety and mixed relationship with the startle reflex and sensitivity to unpredictability. To assess current symptoms, participants completed the self-report Screen for Child Anxiety Related Emotional Disorders and Children’s Depression Inventory. Results indicated that social phobia symptoms were associated with heightened startle potentiation in anticipation of unpredictable threat and attenuated startle potentiation in anticipation of predictable threat. Negative mood and negative self-esteem symptoms were associated with attenuated and heightened startle potentiation in anticipation of unpredictable threat, respectively. All results remained significant after controlling for the other symptom dimensions. The present study provides initial evidence that anxiety and depression symptom dimensions demonstrate unique associations with the startle reflex in anticipation of unpredictable threat in children and adolescents. PMID:27224989

An analysis of beam parameters on proton-acoustic waves through an analytic approach.

PubMed

Kipergil, Esra Aytac; Erkol, Hakan; Kaya, Serhat; Gulsen, Gultekin; Unlu, Mehmet Burcin

2017-06-21

It has been reported that acoustic waves are generated when a high-energy pulsed proton beam is deposited in a small volume within tissue. One possible application of proton-induced acoustics is to get real-time feedback for intra-treatment adjustments by monitoring such acoustic waves. A high spatial resolution in ultrasound imaging may reduce proton range uncertainty. Thus, it is crucial to understand the dependence of the acoustic waves on the proton beam characteristics. In this manuscript, firstly, an analytic solution for the proton-induced acoustic wave is presented to reveal the dependence of the signal on the beam parameters; then it is combined with an analytic approximation of the Bragg curve. The influence of the beam energy, pulse duration and beam diameter variation on the acoustic waveform are investigated. Further analysis is performed regarding the Fourier decomposition of the proton-acoustic signals. Our results show that the smaller spill time of the proton beam upsurges the amplitude of the acoustic wave for a constant number of protons, which is hence beneficial for dose monitoring. The increase in the energy of each individual proton in the beam leads to the spatial broadening of the Bragg curve, which also yields acoustic waves of greater amplitude. The pulse duration and the beam width of the proton beam do not affect the central frequency of the acoustic wave, but they change the amplitude of the spectral components.

[Unconscious Acoustical Stimuli Effects on Event-related Potentials in Humans].

PubMed

Kopeikina, E A; Choroshich, V V; Aleksandrov, A Y; Ivanova, V Y

2015-01-01

Unconscious perception essentially affects human behavior. The main results in this area obtained in experiments with visual stimuli. However, the acoustical stimuli play not less important role in behavior. The main idea of this paper is the electroencephalographic investigation of unconscious acoustical stimulation effects on electro-physiological activity of the brain. For this purpose, the event-related potentials were acquired under unconscious stimulus priming paradigm. The one syllable, three letter length, Russian words and pseudo-words with single letter substitution were used as primes and targets. As a result, we find out that repetition and alternative priming similarly affects the event-related potential's component with 200 ms latency after target application in frontal parietal and temporal areas. Under alternative priming the direction of potential amplitude modification nearby 400 ms was altered for word and semi-word targets. Alternative priming reliably increase ERP's amplitude in 400 ms locality with pseudo-word targets and decrease it under word targets. Taking into account, that all participants were unable to distinguish the applied prime stimuli, we can assume that the event-related potential changes evoked by unconscious perception of acoustical stimuli. The ERP amplitude dynamics revealed in current investigation demonstrate the opportunity of subliminal acoustical stimuli to modulate the electrical activity evoked by verbal acoustical stimulation.

Acoustic representation of tomographic data

NASA Astrophysics Data System (ADS)

Wampler, Cheryl; Zahrt, John D.; Hotchkiss, Robert S.; Zahrt, Rebecca; Kust, Mark

1993-04-01

Tomographic data and tomographic reconstructions are naturally periodic in the angle of rotation of the turntable and the polar angel of the coordinates in the object, respectively. Similarly, acoustic waves are periodic and have amplitude and wavelength as free parameters that can be fit to another representation. Work has been in progress for some time in bringing the acoustic senses to bear on large data sets rather than just the visual sense. We will provide several different acoustic representations of both raw data and density maps. Rather than graphical portrayal of the data and reconstructions, you will be presented various 'tone poems.'

Does trait anxiety influence effects of oxytocin on eye-blink startle reactivity? A randomized, double-blind, placebo-controlled crossover study.

PubMed

Schumacher, Sonja; Oe, Misari; Wilhelm, Frank H; Rufer, Michael; Heinrichs, Markus; Weidt, Steffi; Moergeli, Hanspeter; Martin-Soelch, Chantal

2018-01-01

Previous research has demonstrated that the neuropeptide oxytocin modulates social behaviors and reduces anxiety. However, effects of oxytocin on startle reactivity, a well-validated measure of defense system activation related to fear and anxiety, have been inconsistent. Here we investigated the influence of oxytocin on startle reactivity with particular focus on the role of trait anxiety. Forty-four healthy male participants attended two experimental sessions. They received intranasal oxytocin (24 IU) in one session and placebo in the other. Startle probes were presented in combination with pictures of social and non-social content. Eye-blink startle magnitude was measured by electromyography over the musculus orbicularis oculi in response to 95 dB noise bursts. Participants were assigned to groups of high vs. low trait anxiety based on their scores on the trait form of the Spielberger State-Trait Anxiety Inventory (STAI). A significant interaction effect of oxytocin with STAI confirmed that trait anxiety moderated the effect of oxytocin on startle reactivity. Post-hoc tests indicated that for participants with elevated trait anxiety, oxytocin increased startle magnitude, particularly when watching non-social pictures, while this was not the case for participants with low trait anxiety. Results indicate that effects of oxytocin on defense system activation depend on individual differences in trait anxiety. Trait anxiety may be an important moderator variable that should be considered in human studies on oxytocin effects.

The time course of face processing: startle eyeblink response modulation by face gender and expression.

PubMed

Duval, Elizabeth R; Lovelace, Christopher T; Aarant, Justin; Filion, Diane L

2013-12-01

The purpose of this study was to investigate the effects of both facial expression and face gender on startle eyeblink response patterns at varying lead intervals (300, 800, and 3500ms) indicative of attentional and emotional processes. We aimed to determine whether responses to affective faces map onto the Defense Cascade Model (Lang et al., 1997) to better understand the stages of processing during affective face viewing. At 300ms, there was an interaction between face expression and face gender with female happy and neutral faces and male angry faces producing inhibited startle. At 3500ms, there was a trend for facilitated startle during angry compared to neutral faces. These findings suggest that affective expressions are perceived differently in male and female faces, especially at short lead intervals. Future studies investigating face processing should take both face gender and expression into account. © 2013.

Shear wave elastography using amplitude-modulated acoustic radiation force and phase-sensitive optical coherence tomography

NASA Astrophysics Data System (ADS)

Nguyen, Thu-Mai; Arnal, Bastien; Song, Shaozhen; Huang, Zhihong; Wang, Ruikang K.; O'Donnell, Matthew

2015-01-01

Investigating the elasticity of ocular tissue (cornea and intraocular lens) could help the understanding and management of pathologies related to biomechanical deficiency. In previous studies, we introduced a setup based on optical coherence tomography for shear wave elastography (SWE) with high resolution and high sensitivity. SWE determines tissue stiffness from the propagation speed of shear waves launched within tissue. We proposed acoustic radiation force to remotely induce shear waves by focusing an ultrasound (US) beam in tissue, similar to several elastography techniques. Minimizing the maximum US pressure is essential in ophthalmology for safety reasons. For this purpose, we propose a pulse compression approach. It utilizes coded US emissions to generate shear waves where the energy is spread over a long emission, and then numerically compressed into a short, localized, and high-energy pulse. We used a 7.5-MHz single-element focused transducer driven by coded excitations where the amplitude is modulated by a linear frequency-swept square wave (1 to 7 kHz). An inverse filter approach was used for compression. We demonstrate the feasibility of performing shear wave elastography measurements in tissue-mimicking phantoms at low US pressures (mechanical index <0.6).

Shear wave elastography using amplitude-modulated acoustic radiation force and phase-sensitive optical coherence tomography

PubMed Central

Nguyen, Thu-Mai; Arnal, Bastien; Song, Shaozhen; Huang, Zhihong; Wang, Ruikang K.; O’Donnell, Matthew

2015-01-01

Abstract. Investigating the elasticity of ocular tissue (cornea and intraocular lens) could help the understanding and management of pathologies related to biomechanical deficiency. In previous studies, we introduced a setup based on optical coherence tomography for shear wave elastography (SWE) with high resolution and high sensitivity. SWE determines tissue stiffness from the propagation speed of shear waves launched within tissue. We proposed acoustic radiation force to remotely induce shear waves by focusing an ultrasound (US) beam in tissue, similar to several elastography techniques. Minimizing the maximum US pressure is essential in ophthalmology for safety reasons. For this purpose, we propose a pulse compression approach. It utilizes coded US emissions to generate shear waves where the energy is spread over a long emission, and then numerically compressed into a short, localized, and high-energy pulse. We used a 7.5-MHz single-element focused transducer driven by coded excitations where the amplitude is modulated by a linear frequency-swept square wave (1 to 7 kHz). An inverse filter approach was used for compression. We demonstrate the feasibility of performing shear wave elastography measurements in tissue-mimicking phantoms at low US pressures (mechanical index <0.6). PMID:25554970

Acoustic transient generation in pulsed holmium laser ablation under water

NASA Astrophysics Data System (ADS)

Asshauer, Thomas; Rink, Klaus; Delacretaz, Guy P.; Salathe, Rene-Paul; Gerber, Bruno E.; Frenz, Martin; Pratisto, Hans; Ith, Michael; Romano, Valerio; Weber, Heinz P.

1994-08-01

In this study the role of acoustical transients during pulsed holmium laser ablation is addressed. For this the collapse of cavitation bubbles generated by 2.12 micrometers Cr:Tm:Ho:YAG laser pulses delivered via a fiber in water is investigated. Multiple consecutive collapses of a single bubble generating acoustic transients are documented. Pulse durations are varied from 130 - 230 microsecond(s) and pulse energies from 20 - 800 mJ. Fiber diameters of 400 and 600 micrometers are used. The bubble collapse behavior is observed by time resolved fast flash photography with 1 microsecond(s) strobe lamp or 5 ns 1064 nm Nd:YAG laser illumination. A PVDF needle probe transducer is used to observe acoustic transients and measure their pressure amplitudes. Under certain conditions, at the end of the collapse phase the bubbles emit spherical acoustic transients of up to several hundred bars amplitude. After the first collapse up to two rebounds leading to further acoustic transient emissions are observed. Bubbles generated near a solid surface under water are attracted towards the surface during their development. The final phase of the collapse generating the acoustic transients takes place directly on the surface, exposing it to maximum pressure amplitudes. Our results indicate a possible mechanism of unwanted tissue damage during holmium laser application in a liquid environment as in arthroscopy or angioplasty that may set limits to the choice of laser pulse duration and energies.

Anxiety and Depression Symptom Dimensions Demonstrate Unique Relationships with the Startle Reflex in Anticipation of Unpredictable Threat in 8 to 14 Year-Old Girls.

PubMed

Nelson, Brady D; Hajcak, Greg

2017-02-01

There is growing evidence that heightened sensitivity to unpredictability is a core mechanism of anxiety disorders. In adults, multiple anxiety disorders have been associated with a heightened startle reflex in anticipation of unpredictable threat. Child and adolescent anxiety has been linked to an increased startle reflex across baseline, safety, and threat conditions. However, it is unclear whether anxiety in youth is related to the startle reflex as a function of threat predictability. In a sample of 90 8 to 14 year-old girls, the present study examined the association between anxiety symptom dimensions and startle potentiation during a no, predictable, and unpredictable threat task. Depression symptom dimensions were also examined given their high comorbidity with anxiety and mixed relationship with the startle reflex and sensitivity to unpredictability. To assess current symptoms, participants completed the self-report Screen for Child Anxiety Related Emotional Disorders and Children's Depression Inventory. Results indicated that social phobia symptoms were associated with heightened startle potentiation in anticipation of unpredictable threat and attenuated startle potentiation in anticipation of predictable threat. Negative mood and negative self-esteem symptoms were associated with attenuated and heightened startle potentiation in anticipation of unpredictable threat, respectively. All results remained significant after controlling for the other symptom dimensions. The present study provides initial evidence that anxiety and depression symptom dimensions demonstrate unique associations with the startle reflex in anticipation of unpredictable threat in children and adolescents.

Robust analysis method for acoustic properties of biological specimens measured by acoustic microscopy

NASA Astrophysics Data System (ADS)

Arakawa, Mototaka; Mori, Shohei; Kanai, Hiroshi; Nagaoka, Ryo; Horie, Miki; Kobayashi, Kazuto; Saijo, Yoshifumi

2018-07-01

We proposed a robust analysis method for the acoustic properties of biological specimens measured by acoustic microscopy. Reflected pulse signals from the substrate and specimen were converted into frequency domains to obtain sound speed and thickness. To obtain the average acoustic properties of the specimen, parabolic approximation was performed to determine the frequency at which the amplitude of the normalized spectrum became maximum or minimum, considering the sound speed and thickness of the specimens and the operating frequency of the ultrasonic device used. The proposed method was demonstrated for a specimen of malignant melanoma of the skin by using acoustic microscopy attaching a concave transducer with a center frequency of 80 MHz. The variations in sound speed and thickness analyzed by the proposed method were markedly smaller than those analyzed by the method based on an autoregressive model. The proposed method is useful for the analysis of the acoustic properties of bilogical tissues or cells.

The acoustic correlates of valence depend on emotion family.

PubMed

Belyk, Michel; Brown, Steven

2014-07-01

The voice expresses a wide range of emotions through modulations of acoustic parameters such as frequency and amplitude. Although the acoustics of individual emotions are well understood, attempts to describe the acoustic correlates of broad emotional categories such as valence have yielded mixed results. In the present study, we analyzed the acoustics of emotional valence for different families of emotion. We divided emotional vocalizations into "motivational," "moral," and "aesthetic" families as defined by the OCC (Ortony, Clore, and Collins) model of emotion. Subjects viewed emotional scenarios and were cued to vocalize congruent exclamations in response to them, for example, "Yay!" and "Damn!". Positive valence was weakly associated with high-pitched and loud vocalizations. However, valence interacted with emotion family for both pitch and amplitude. A general acoustic code for valence does not hold across families of emotion, whereas family-specific codes provide a more accurate description of vocal emotions. These findings are consolidated into a set of "rules of expression" relating vocal dimensions to emotion dimensions. Copyright © 2014 The Voice Foundation. Published by Mosby, Inc. All rights reserved.

Linking Dimensional Models of Internalizing Psychopathology to Neurobiological Systems: Affect-Modulated Startle as an Indicator of Fear and Distress Disorders and Affiliated Traits

PubMed Central

Vaidyanathan, Uma; Patrick, Christopher J.; Cuthbert, Bruce N.

2009-01-01

Integrative hierarchical models have sought to account for the extensive comorbidity between various internalizing disorders in terms of broad individual difference factors these disorders share. However, such models have been developed largely on the basis of self-report and diagnostic symptom data. Toward the goal of linking such models to neurobiological systems, we review studies that have employed variants of the affect-modulated startle paradigm to investigate emotional processing in internalizing disorders as well as personality constructs known to be associated with these disorders. Specifically, we focus on four parameters of startle reactivity: fear-potentiated startle, inhibition of startle in the context of pleasant stimuli, context-potentiated startle, and general startle reactivity. On the basis of available data, we argue that these varying effects index differing neurobiological processes related to mood and anxiety disorders that are interpretable from the standpoint of dimensional models of the internalizing spectrum. Further, we contend that these empirical findings can feed back into and help reshape conceptualizations of internalizing disorders in ways that make them more amenable to neurobiological analysis. PMID:19883142

Oxytocin receptor neurotransmission in the dorsolateral bed nucleus of the stria terminalis facilitates the acquisition of cued fear in the fear-potentiated startle paradigm in rats.

PubMed

Moaddab, Mahsa; Dabrowska, Joanna

2017-07-15

Oxytocin (OT) is a hypothalamic neuropeptide that modulates fear and anxiety-like behaviors. Dorsolateral bed nucleus of the stria terminalis (BNST dl ) plays a critical role in the regulation of fear and anxiety, and expresses high levels of OT receptor (OTR). However, the role of OTR neurotransmission within the BNST dl in mediating these behaviors is unknown. Here, we used adult male Sprague-Dawley rats to investigate the role of OTR neurotransmission in the BNST dl in the modulation of the acoustic startle response, as well as in the acquisition and consolidation of conditioned fear using fear potentiated startle (FPS) paradigm. Bilateral intra-BNST dl administration of OT (100 ng) did not affect the acquisition of conditioned fear response. However, intra-BNST dl administration of specific OTR antagonist (OTA), (d(CH 2 ) 5 1 , Tyr(Me) 2 , Thr 4 , Orn 8 , des-Gly-NH 2 9 )-vasotocin, (200 ng), prior to the fear conditioning session, impaired the acquisition of cued fear, without affecting a non-cued fear component of FPS. Neither OTA, nor OT affected baseline startle or shock reactivity during fear conditioning. Therefore, the observed impairment of cued fear after OTA infusion resulted from the specific effect on the formation of cued fear. In contrast to the acquisition, neither OTA nor OT affected the consolidation of FPS, when administered after the completion of fear conditioning session. Taken together, these results reveal the important role of OTR neurotransmission in the BNST dl in the formation of conditioned fear to a discrete cue. This study also highlights the role of the BNST dl in learning to discriminate between threatening and safe stimuli. Copyright © 2017 Elsevier Ltd. All rights reserved.

Prediction of the acoustic and bubble fields in insonified freeze-drying vials.

PubMed

Louisnard, O; Cogné, C; Labouret, S; Montes-Quiroz, W; Peczalski, R; Baillon, F; Espitalier, F

2015-09-01

The acoustic field and the location of cavitation bubble are computed in vials used for freeze-drying, insonified from the bottom by a vibrating plate. The calculations rely on a nonlinear model of sound propagation in a cavitating liquid [Louisnard, Ultrason. Sonochem., 19, (2012) 56-65]. Both the vibration amplitude and the liquid level in the vial are parametrically varied. For low liquid levels, a threshold amplitude is required to form a cavitation zone at the bottom of the vial. For increasing vibration amplitudes, the bubble field slightly thickens but remains at the vial bottom, and the acoustic field saturates, which cannot be captured by linear acoustics. On the other hand, increasing the liquid level may promote the formation of a secondary bubble structure near the glass wall, a few centimeters below the free liquid surface. These predictions suggest that rather complex acoustic fields and bubble structures can arise even in such small volumes. As the acoustic and bubble fields govern ice nucleation during the freezing step, the final crystal's size distribution in the frozen product may crucially depend on the liquid level in the vial. Copyright © 2015 Elsevier B.V. All rights reserved.

Computation of Sound Generated by Flow Over a Circular Cylinder: An Acoustic Analogy Approach

NASA Technical Reports Server (NTRS)

Brentner, Kenneth S.; Cox, Jared S.; Rumsey, Christopher L.; Younis, Bassam A.

1997-01-01

The sound generated by viscous flow past a circular cylinder is predicted via the Lighthill acoustic analogy approach. The two dimensional flow field is predicted using two unsteady Reynolds-averaged Navier-Stokes solvers. Flow field computations are made for laminar flow at three Reynolds numbers (Re = 1000, Re = 10,000, and Re = 90,000) and two different turbulent models at Re = 90,000. The unsteady surface pressures are utilized by an acoustics code that implements Farassat's formulation 1A to predict the acoustic field. The acoustic code is a 3-D code - 2-D results are found by using a long cylinder length. The 2-D predictions overpredict the acoustic amplitude; however, if correlation lengths in the range of 3 to 10 cylinder diameters are used, the predicted acoustic amplitude agrees well with experiment.

Photo-acoustic sensor based on an inexpensive piezoelectric film transducer and an amplitude-stabilized single-mode external cavity diode laser for in vitro measurements of glucose concentration

NASA Astrophysics Data System (ADS)

Bayrakli, Ismail; Erdogan, Yasar Kemal

2018-06-01

The present paper focuses on development of a compact photo-acoustic sensor using inexpensive components for glucose analysis. An amplitude-stabilized wavelength-tunable single-mode external cavity diode laser operating around 1050 nm was realized and characterized for the use of laser beam as an excitation light source. In the established setup, a fine tuning range of 9 GHz was achieved. The glucose solution was obtained by diluting D-glucose in sterile water. The acoustic signal generated by the optical excitation was detected via a chip piezoelectric film transducer. A detection limit of 50 mM (900 mg/dl) was achieved. The device may be of great interest for its applications in medicine and health monitoring. The sensor is promising for non-invasive in vivo glucose measurements from interstitial fluid.

Photoacoustic microbeam-oscillator with tunable resonance direction and amplitude

NASA Astrophysics Data System (ADS)

Wu, Qingjun; Li, Fanghao; Wang, Bo; Yi, Futing; Jiang, J. Z.; Zhang, Dongxian

2018-01-01

We successfully design one photoacoustic microbeam-oscillator actuated by nanosecond laser, which exhibits tunable resonance direction and amplitude. The mechanism of laser induced oscillation is systematically analyzed. Both simulation and experimental results reveal that the laser induced acoustic wave propagates in a multi-reflected mode, resulting in resonance in the oscillator. This newly-fabricated micrometer-sized beam-oscillator has an excellent actuation function, i.e., by tuning the laser frequency, the direction and amplitude of actuation can be efficiently altered, which will have potential industrial applications.

Is boldness a resource-holding potential trait? Fighting prowess and changes in startle response in the sea anemone, Actinia equina.

PubMed

Rudin, Fabian S; Briffa, Mark

2012-05-22

Contest theory predicts the evolution of a stable mixture of different strategies for fighting. Here, we investigate the possibility that stable between-individual differences in startle-response durations influence fighting ability or 'resource-holding potential' (RHP) in the beadlet sea anemone, Actinia equina. Both winners and losers showed significant repeatability of pre-fight startle-response durations but mean pre-fight startle-response durations were greater for eventual losers than for eventual winners, indicating that RHP varies with boldness. In particular, individuals with short startle responses inflicted more attacks on their opponent. Both repeatability and mean-level responses were changed by the experience of fighting, and these changes varied with outcome. In losers, repeatability was disrupted to a greater extent and the mean startle-response durations were subject to a greater increase than in winners. Thus, following a fight, this behavioural correlate of RHP behaves in a way similar to post-fight changes in physiological status, which can also vary between winners and losers. Understanding the links between aggression and boldness therefore has the potential to enhance our understanding of both the evolution of animal personality and the 'winner and loser effects' of post-fight changes in RHP.

Investigation of air-assisted sprays submitted to high frequency transverse acoustic fields: Droplet clustering

NASA Astrophysics Data System (ADS)

Ficuciello, A.; Blaisot, J. B.; Richard, C.; Baillot, F.

2017-06-01

An experimental investigation of the effects of a high amplitude transverse acoustic field on coaxial jets is presented in this paper. Water and air are used as working fluids at ambient pressure. The coaxial injectors are placed on the top of a semi-open resonant cavity where the acoustic pressure fluctuations of the standing wave can reach a maximum peak-to-peak amplitude of 12 kPa at the forcing frequency of 1 kHz. Several test conditions are considered in order to quantify the influence of injection conditions, acoustic field amplitude, and injector position with respect to the standing wave acoustic field. A high speed back-light visualization technique is used to characterize the jet response. Image processing is used to obtain valuable information about the jet behavior. It is shown that the acoustic field drastically affects the atomization process for all atomization regimes. The position of the injector in the acoustic field determines the jet response, and a droplet-clustering phenomenon is highlighted in multi-point injection conditions and quantified by determining discrete droplet location distributions. A theoretical model based on nonlinear acoustics related to the spatial distribution of the radiation pressure exerted on an object explains the behavior observed.

Ion acoustic wave assisted laser beat wave terahertz generation in a plasma channel

NASA Astrophysics Data System (ADS)

Tyagi, Yachna; Tripathi, Deepak; Walia, Keshav; Garg, Deepak

2018-04-01

Resonant excitation of terahertz (THz) radiation by non-linear mixing of two lasers in the presence of an electrostatic wave is investigated. The electrostatic wave assists in k matching and contributes to non-linear coupling. In this plasma channel, the electron plasma frequency becomes minimum on the axis. The beat frequency ponderomotive force imparts an oscillating velocity to the electrons. In the presence of an ion-acoustic wave, density perturbation due to the ion-acoustic wave couples with the oscillating velocity of the electrons and give rise to non-linear current that gives rise to an ion-acoustic wave frequency assisted THz radiation field. The normalized field amplitude of ion acoustic wave assisted THz varies inversely for ω/ωp . The field amplitude of ion acoustic wave assisted THz decreases as ω/ωp increases.

Is amplitude loss of sonic waveforms due to intrinsic attenuation or source coupling to the medium?

USGS Publications Warehouse

Lee, Myung W.

2006-01-01

Sonic waveforms acquired in gas-hydrate-bearing sediments indicate strong amplitude loss associated with an increase in sonic velocity. Because the gas hydrate increases sonic velocities, the amplitude loss has been interpreted as due to intrinsic attenuation caused by the gas hydrate in the pore space, which apparently contradicts conventional wave propagation theory. For a sonic source in a fluid-filled borehole, the signal amplitude transmitted into the formation depends on the physical properties of the formation, including any pore contents, in the immediate vicinity of the source. A signal in acoustically fast material, such as gas-hydrate-bearing sediments, has a smaller amplitude than a signal in acoustically slower material. Therefore, it is reasonable to interpret the amplitude loss in the gas-hydrate-bearing sediments in terms of source coupling to the surrounding medium as well as intrinsic attenuation. An analysis of sonic waveforms measured at the Mallik 5L-38 well, Northwest Territories, Canada, indicates that a significant part of the sonic waveform's amplitude loss is due to a source-coupling effect. All amplitude analyses of sonic waveforms should include the effect of source coupling in order to accurately characterize the formation's intrinsic attenuation.

Prediction for potential landslide zones using seismic amplitude in Liwan gas field, northern South China Sea

NASA Astrophysics Data System (ADS)

Li, Xishuang; Liu, Baohua; Liu, Lejun; Zheng, Jiewen; Zhou, Songwang; Zhou, Qingjie

2017-12-01

The Liwan (Lw) gas field located in the northern slope of the South China Sea (SCS) is extremely complex for its sea-floor topograghy, which is a huge challenge for the safety of subsea facilities. It is economically impractical to obtain parameters for risk assessment of slope stability through a large amount of sampling over the whole field. The linkage between soil shear strength and seabed peak amplitude derived from 2D/3D seismic data is helpful for understanding the regional slope-instability risk. In this paper, the relationships among seabed peak, acoustic impedance and shear strength of shallow soil in the study area were discussed based on statistical analysis results. We obtained a similar relationship to that obtained in other deep-water areas. There is a positive correlation between seabed peak amplitude and acoustic impedance and an exponential relationship between acoustic impedance and shear strength of sediment. The acoustic impedance is the key factor linking the seismic amplitude and shear strength. Infinite slope stability analysis results indicate the areas have a high potential of shallow landslide on slopes exceeding 15° when the thickness of loose sediments exceeds 8 m in the Lw gas field. Our prediction shows that they are mainly located in the heads and walls of submarine canyons.

Properties of Materials Using Acoustic Waves.

DTIC Science & Technology

1985-10-01

8217 cavitation , lIevitation, 20, ABSTRACT (Continue Met mrevr aide it necessary and Idenltt, A,’ block number) Our goal of characterizing materials using...to clean even though there are surfactants in it, and it allows us to study the large amplitude oscillations without worrying about cavitation or the...34Acoustics Cavitation Inception," Ultrasonics 22, 167 (1984). Richard McGowan, "Steady Second-Order Effects in Acoustics and the Method of Matched Asymptotic

Effects of Nanoparticulate Additives on Acoustically Coupled Fuel Droplet Combustion

NASA Astrophysics Data System (ADS)

Vargas, Andres; Plascencia, Miguel; Sim, Hyung Sub; Smith, Owen; Karagozian, Ann

2017-11-01

The present study investigates interactions between applied acoustic perturbations and burning ethanol droplets containing nano particulate additives. Reactive nanoscale aluminum (nAl) as well as inert silica (nSiO2), each with an 80 nm average diameter. Continuously-fed fuel droplet combustion experiments were conducted in the vicinity of a pressure node created in a closed acoustic waveguide, with a range of applied forcing frequencies, pressure or velocity perturbation amplitudes, and particle loading concentrations. Simultaneous phase-locked OH* chemiluminescence and high-speed visible imaging enabled quantification of the influences of nanoparticle concentration on burning rate constant K and combustion-acoustic coupling. Results indicated that nAl particles in ethanol yielded measurable increases in K with increasing applied perturbation amplitudes, as compared to pure ethanol in the presence of acoustic excitation. Droplets with nAl exposed to moderate acoustic excitation exhibited sustained combustion for much longer periods of time than for unforced conditions. Post analysis of particulate matter collected from residue via electron microscopy aids in interpreting these trends and findings. Supported by AFOSR Grant FA9550-15-1-0339.

Dual excitation acoustic paramagnetic logging tool

DOEpatents

Vail, III, William B.

1989-01-01

New methods and apparatus are disclosed which allow measurement of the presence of oil and water in gelogical formations using a new physical effect called the Acoustic Paramagnetic Logging Effect (APLE). The presence of petroleum in formation causes a slight increase in the earth's magnetic field in the vicinity of the reservoir. This is the phenomena of paramagnetism. Application of an acoustic source to a geological formation at the Larmor frequency of the nucleous present causes the paramagnetism of the formation to disappear. This results in a decrease in the earth's magnetic field in the vicinity of the oil bearing formation. Repetitively frequency sweeping the acoustic source through the Larmor frequency of the nucleons present (approx. 2 kHz) causes an amplitude modulation of the earth's magnetic field which is a consequence of the APLE. The amplitude modulation of the earth's magnetic field is measured with an induction coil gradiometer and provides a direct measure of the amount of oil and water in the excitation zone of the formation. The phase of the signal is used to infer the longitudinal relaxation times of the fluids present, which results in the ability in general to separate oil and water and to measure the viscosity of the oil present. Such measurements may be preformed in open boreholes and in cased well bores. The Dual Excitation Acoustic Paramagnetic Logging Tool employing two acoustic sources is also described.

Dual excitation acoustic paramagnetic logging tool

DOEpatents

Vail, W.B. III.

1989-02-14

New methods and apparatus are disclosed which allow measurement of the presence of oil and water in geological formations using a new physical effect called the Acoustic Paramagnetic Logging Effect (APLE). The presence of petroleum in formation causes a slight increase in the earth's magnetic field in the vicinity of the reservoir. This is the phenomena of paramagnetism. Application of an acoustic source to a geological formation at the Larmor frequency of the nucleons present causes the paramagnetism of the formation to disappear. This results in a decrease in the earth's magnetic field in the vicinity of the oil bearing formation. Repetitively frequency sweeping the acoustic source through the Larmor frequency of the nucleons present (approx. 2 kHz) causes an amplitude modulation of the earth's magnetic field which is a consequence of the APLE. The amplitude modulation of the earth's magnetic field is measured with an induction coil gradiometer and provides a direct measure of the amount of oil and water in the excitation zone of the formation. The phase of the signal is used to infer the longitudinal relaxation times of the fluids present, which results in the ability in general to separate oil and water and to measure the viscosity of the oil present. Such measurements may be performed in open boreholes and in cased well bores. The Dual Excitation Acoustic Paramagnetic Logging Tool employing two acoustic sources is also described. 6 figs.

Sleep duration, depression, and oxytocinergic genotype influence prepulse inhibition of the startle reflex in postpartum women.

PubMed

Comasco, Erika; Gulinello, Maria; Hellgren, Charlotte; Skalkidou, Alkistis; Sylven, Sara; Sundström-Poromaa, Inger

2016-04-01

The postpartum period is characterized by a post-withdrawal hormonal status, sleep deprivation, and susceptibility to affective disorders. Postpartum mothering involves automatic and attentional processes to screen out new external as well as internal stimuli. The present study investigated sensorimotor gating in relation to sleep duration, depression, as well as catecholaminergic and oxytocinergic genotypes in postpartum women. Prepulse inhibition (PPI) of the startle reflex and startle reactivity were assessed two months postpartum in 141 healthy and 29 depressed women. The catechol-O-methyltransferase (COMT) Val158Met, and oxytocin receptor (OXTR) rs237885 and rs53576 polymorphisms were genotyped, and data on sleep duration were collected. Short sleep duration (less than four hours in the preceding night) and postpartum depression were independently associated with lower PPI. Also, women with postpartum depression had higher startle reactivity in comparison with controls. The OXTR rs237885 genotype was related to PPI in an allele dose-dependent mode, with T/T healthy postpartum women carriers displaying the lowest PPI. Reduced sensorimotor gating was associated with sleep deprivation and depressive symptoms during the postpartum period. Individual neurophysiological vulnerability might be mediated by oxytocinergic genotype which relates to bonding and stress response. These findings implicate the putative relevance of lower PPI of the startle response as an objective physiological correlate of liability to postpartum depression. Copyright © 2016 Elsevier B.V. and ECNP. All rights reserved.

Comparison of Travel-Time and Amplitude Measurements for Deep-Focusing Time-Distance Helioseismology

NASA Astrophysics Data System (ADS)

Pourabdian, Majid; Fournier, Damien; Gizon, Laurent

2018-04-01

The purpose of deep-focusing time-distance helioseismology is to construct seismic measurements that have a high sensitivity to the physical conditions at a desired target point in the solar interior. With this technique, pairs of points on the solar surface are chosen such that acoustic ray paths intersect at this target (focus) point. Considering acoustic waves in a homogeneous medium, we compare travel-time and amplitude measurements extracted from the deep-focusing cross-covariance functions. Using a single-scattering approximation, we find that the spatial sensitivity of deep-focusing travel times to sound-speed perturbations is zero at the target location and maximum in a surrounding shell. This is unlike the deep-focusing amplitude measurements, which have maximum sensitivity at the target point. We compare the signal-to-noise ratio for travel-time and amplitude measurements for different types of sound-speed perturbations, under the assumption that noise is solely due to the random excitation of the waves. We find that, for highly localized perturbations in sound speed, the signal-to-noise ratio is higher for amplitude measurements than for travel-time measurements. We conclude that amplitude measurements are a useful complement to travel-time measurements in time-distance helioseismology.

Physiological, anatomical, and behavioral changes after acoustic trauma in Drosophila melanogaster

PubMed Central

Christie, Kevin W.; Sivan-Loukianova, Elena; Smith, Wesley C.; Aldrich, Benjamin T.; Schon, Michael A.; Roy, Madhuparna; Lear, Bridget C.; Eberl, Daniel F.

2013-01-01

Noise-induced hearing loss (NIHL) is a growing health issue, with costly treatment and lost quality of life. Here we establish Drosophila melanogaster as an inexpensive, flexible, and powerful genetic model system for NIHL. We exposed flies to acoustic trauma and quantified physiological and anatomical effects. Trauma significantly reduced sound-evoked potential (SEP) amplitudes and increased SEP latencies in control genotypes. SEP amplitude but not latency effects recovered after 7 d. Although trauma produced no gross morphological changes in the auditory organ (Johnston’s organ), mitochondrial cross-sectional area was reduced 7 d after exposure. In nervana 3 heterozygous flies, which slightly compromise ion homeostasis, trauma had exaggerated effects on SEP amplitude and mitochondrial morphology, suggesting a key role for ion homeostasis in resistance to acoustic trauma. Thus, Drosophila exhibit acoustic trauma effects resembling those found in vertebrates, including inducing metabolic stress in sensory cells. This report of noise trauma in Drosophila is a foundation for studying molecular and genetic sequelae of NIHL. PMID:24003166

Cross-Channel Amplitude Sweeps Are Crucial to Speech Intelligibility

ERIC Educational Resources Information Center

Prendergast, Garreth; Green, Gary G. R.

2012-01-01

Classical views of speech perception argue that the static and dynamic characteristics of spectral energy peaks (formants) are the acoustic features that underpin phoneme recognition. Here we use representations where the amplitude modulations of sub-band filtered speech are described, precisely, in terms of co-sinusoidal pulses. These pulses are…

Validating a human model for anxiety using startle potentiated by cue and context: the effects of alprazolam, pregabalin, and diphenhydramine

PubMed Central

Mol, N.; Kenemans, J. L.; Prinssen, E. P.; Niklson, I.; Xia-Chen, C.; Broeyer, F.; van Gerven, J.

2009-01-01

Background Fear-potentiated startle has been suggested as a translational model for evaluating efficacy of anxiolytic compounds in humans. Several known anxiolytic compounds have been tested as well as several putative anxiolytics. Because results of these studies have been equivocal, the aim of the present study was to examine another pharmacological permutation of the human potentiated startle model by comparing two anxiolytic agents to a non-anxiolytic sedative and placebo. Methods Twenty healthy volunteers participated in a double-blind, placebo-controlled, cross-over study with four sessions in which they received single doses of the anxiolytics alprazolam (1 mg) and pregabalin (200 mg), as well as diphenhydramine (50 mg) as a non-anxiolytic sedative control and placebo. The design included a cued shock condition that presumably evokes fear and an unpredictable shock context condition presumably evoking anxiety. Results None of the treatments reliably reduced either fear- or anxiety-potentiated startle. Alprazolam and diphenhydramine reduced overall baseline startle. Alprazolam was found to only affect contextual anxiety in a statistical significant way after two subjects who failed to show a contextual anxiety effect in the placebo condition were excluded from the analysis. Pregabalin did not significantly affect any of the physiological measures. Discussion The negative findings from this study are discussed in terms of methodological differences between designs and in variability of startle both between and within study participants. Conclusion Even though fear-potentiated startle may be used to translate preclinical evidence to human populations, methodological issues still hamper the application of this model to early screening of putative anxiolytic drugs. PMID:19415242

Perinatal exposure to the selective serotonin reuptake inhibitor citalopram alters spatial learning and memory, anxiety, depression, and startle in Sprague-Dawley rats.

PubMed

Sprowles, Jenna L N; Hufgard, Jillian R; Gutierrez, Arnold; Bailey, Rebecca A; Jablonski, Sarah A; Williams, Michael T; Vorhees, Charles V

2016-11-01

Selective serotonin reuptake inhibitors (SSRIs) block the serotonin (5-HT) reuptake transporter (SERT) and increase synaptic 5-HT. 5-HT is also important in brain development; hence when SSRIs are taken during pregnancy there exists the potential for these drugs to affect CNS ontogeny. Prenatal SSRI exposure has been associated with an increased prevalence of autism spectrum disorder (ASD), and peripheral 5-HT is elevated in some ASD patients. Perinatal SSRI exposure in rodents has been associated with increased depression and anxiety-like behavior, decreased sociability, and impaired learning in the offspring, behaviors often seen in ASD. The present study investigated whether perinatal exposure to citalopram causes persistent neurobehavioral effects. Gravid Sprague-Dawley rats were assigned to two groups and subcutaneously injected twice per day with citalopram (10mg/kg; Cit) or saline (Sal) 6h apart on embryonic day (E)6-21, and then drug was given directly to the pups after delivery from postnatal day (P)1-20. Starting on P60, one male/female from each litter was tested in the Cincinnati water maze (CWM) and open-field before and after MK-801. A second pair from each litter was tested in the Morris water maze (MWM) and open-field before and after (+)-amphetamine. A third pair was tested as follows: elevated zero-maze, open-field, marble burying, prepulse inhibition of acoustic startle, social preference, and forced swim. Cit-exposed rats were impaired in the MWM during acquisition and probe, but not during reversal, shift, or cued trials. Cit-exposed rats also showed increased marble burying, decreased time in the center of the open-field, decreased latency to immobility in forced swim, and increased acoustic startle across prepulse intensities with no effects on CWM. The results are consistent with citalopram inducing several ASD-like effects. The findings add to concerns about use of SSRIs during pregnancy. Further research on different classes of

Acoustic Waves in a Three-Dimensional Stratified Atmosphere

NASA Astrophysics Data System (ADS)

Kalkofen, W.; Massaglia, S.; Bodo, G.; Rossi, P.

2000-05-01

We investigate the propagation of acoustic waves in a three-dimensional, nonmagnetic, isothermal atmosphere stratified in plane-parallel layers in a study of oscillations in chromospheric calcium bright points. We present analytic results for the linear and numerical results for the nonlinear evolution of a disturbance. An impulsively excited acoustic disturbance emanates from a point source and propagates outward as a spherical acoustic wave, amplifying exponentially in the upward direction. A significant wave amplitude is found only in a relatively narrow cone about the vertical. The amplitude of the wave and the opening angle of the cone decrease with time. Because of the lateral spread of the upward-propagating energy, the decay is faster in 2D and 3D simulations than in 1D. We discuss observational consequences of this scenario, some of which are not anticipated from 1D calculations. We acknowledge support from NASA, NSF and the Ministero per l'Università e la Ricerca Scientifica e Tecnologica.

The Effect of Microphone Type on Acoustical Measures of Synthesized Vowels.

PubMed

Kisenwether, Jessica Sofranko; Sataloff, Robert T

2015-09-01

The purpose of this study was to compare microphones of different directionality, transducer type, and cost, with attention to their effects on acoustical measurements of period perturbation, amplitude perturbation, and noise using synthesized sustained vowel samples. This was a repeated measures design. Synthesized sustained vowel stimuli (with known acoustic characteristics and systematic changes in jitter, shimmer, and noise-to-harmonics ratio) were recorded by a variety of dynamic and condenser microphones. Files were then analyzed for mean fundamental frequency (fo), fo standard deviation, absolute jitter, shimmer in dB, peak-to-peak amplitude variation, and noise-to-harmonics ratio. Acoustical measures following recording were compared with the synthesized, known acoustical measures before recording. Although informal analyses showed some differences among microphones, and analyses of variance showed that type of microphone is a significant predictor, t-tests revealed that none of the microphones generated different means compared with the generated acoustical measures. In this sample, microphone type, directionality, and cost did not have a significant effect on the validity of acoustic measures. Copyright © 2015 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

Optical Quantification of Harmonic Acoustic Radiation Force Excitation in a Tissue-Mimicking Phantom.

PubMed

Suomi, Visa; Edwards, David; Cleveland, Robin

2015-12-01

Optical tracking was used to characterize acoustic radiation force-induced displacements in a tissue-mimicking phantom. Amplitude-modulated 3.3-MHz ultrasound was used to induce acoustic radiation force in the phantom, which was embedded with 10-μm microspheres that were tracked using a microscope objective and high-speed camera. For sine and square amplitude modulation, the harmonic components of the fundamental and second and third harmonic frequencies were measured. The displacement amplitudes were found to increase linearly with acoustic radiation force up to 10 μm, with sine modulation having 19.5% lower peak-to-peak amplitude values than square modulation. Square modulation produced almost no second harmonic, but energy was present in the third harmonic. For the sine modulation, energy was present in the second harmonic and low energy in the third harmonic. A finite-element model was used to simulate the deformation and was both qualitatively and quantitatively in agreement with the measurements. Copyright © 2015 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Vibration of a single microcapsule with a hard plastic shell in an acoustic standing wave field.

PubMed

Koyama, Daisuke; Kotera, Hironori; Kitazawa, Natsuko; Yoshida, Kenji; Nakamura, Kentaro; Watanabe, Yoshiaki

2011-04-01

Observation techniques for measuring the small vibration of a single microcapsule of tens of nanometers in an acoustic standing wave field are discussed. First, simultaneous optical observation of a microbubble vibration by two methods is investigated, using a high-speed video camera, which permits two-dimensional observation of the bubble vibration, and a laser Doppler vibrometer (LDV), which can observe small bubble vibration amplitudes at high frequency. Bubbles of tens of micrometers size were trapped at the antinode of an acoustic standing wave generated in an observational cell. Bubble vibration at 27 kHz could be observed and the experimental results for the two methods showed good agreement. The radial vibration of microcapsules with a hard plastic shell was observed using the LDV and the measurement of the capsule vibration with radial oscillation amplitude of tens of nanometers was successful. The acoustic radiation force acting on microcapsules in the acoustic standing wave was measured from the trapped position of the standing wave and the radial oscillation amplitude of the capsules was estimated from the theoretical equation of the acoustic radiation force, giving results in good agreement with the LDV measurements. The radial oscillation amplitude of a capsule was found to be proportional to the amplitude of the driving sound pressure. A larger expansion ratio was observed for capsules closer to the resonance condition under the same driving sound pressure and frequency. © 2011 IEEE

Acoustic paramagnetic logging tool

DOEpatents

Vail, III, William B.

1988-01-01

New methods and apparatus are disclosed which allow measurement of the presence of oil and water in geological formations using a new physical effect called the Acoustic Paramagnetic Logging Effect (APLE). The presence of petroleum in formation causes a slight increase in the earth's magnetic field in the vicinity of the reservoir. This is the phenomena of paramagnetism. Application of an acoustic source to a geological formation at the Larmor frequency of the nucleons present causes the paramagnetism of the formation to disappear. This results in a decrease in the earth3 s magnetic field in the vicinity of the oil bearing formation. Repetitively frequency sweeping the acoustic source through the Larmor frequency of the nucleons present (approx. 2 kHz) causes an amplitude modulation of the earth's magnetic field which is a consequence of the APLE. The amplitude modulation of the earth's magnetic field is measured with an induction coil gradiometer and provides a direct measure of the amount of oil and water in the excitation zone of the formation . The phase of the signal is used to infer the longitudinal relaxation times of the fluids present, which results in the ability in general to separate oil and water and to measure the viscosity of the oil present. Such measurements may be preformed in open boreholes and in cased well bores.

Frustrated total internal reflection acoustic field sensor

DOEpatents

Kallman, Jeffrey S.

2000-01-01

A frustrated total internal reflection acoustic field sensor which allows the acquisition of the acoustic field over an entire plane, all at once. The sensor finds use in acoustic holography and acoustic diffraction tomography. For example, the sensor may be produced by a transparent plate with transparent support members tall enough to support one or more flexible membranes at an appropriate height for frustrated total internal reflection to occur. An acoustic wave causes the membrane to deflect away from its quiescent position and thus changes the amount of light that tunnels through the gap formed by the support members and into the membrane, and so changes the amount of light reflected by the membrane. The sensor(s) is illuminated by a uniform tight field, and the reflection from the sensor yields acoustic wave amplitude and phase information which can be picked up electronically or otherwise.

Oxytocin and Social Support as Synergistic Inhibitors of Aversive Fear Conditioning and Fear-Potentiated Startle in Male Rats

DTIC Science & Technology

2011-05-01

uring fear extinction in PTSD : an fMRI Study . CNS Neurosci Ther, print copy in press (originally published online 16 April 2010, at http://www3...alleviate one or more physiopathologies of PTSD . The effect of oxytocin on background anxiety in our fear- potentiated startle studies in rats is also...benefits for patients with PTSD . fear; anxiety; PTSD ; startle; social isolation 60 jrosen@udel.edu Table of Contents

Acoustic and Perceptual Effects of Left–Right Laryngeal Asymmetries Based on Computational Modeling

PubMed Central

Samlan, Robin A.; Story, Brad H.; Lotto, Andrew J.; Bunton, Kate

2015-01-01

Purpose Computational modeling was used to examine the consequences of 5 different laryngeal asymmetries on acoustic and perceptual measures of vocal function. Method A kinematic vocal fold model was used to impose 5 laryngeal asymmetries: adduction, edge bulging, nodal point ratio, amplitude of vibration, and starting phase. Thirty /a/ and /I/ vowels were generated for each asymmetry and analyzed acoustically using cepstral peak prominence (CPP), harmonics-to-noise ratio (HNR), and 3 measures of spectral slope (H1*-H2*, B0-B1, and B0-B2). Twenty listeners rated voice quality for a subset of the productions. Results Increasingly asymmetric adduction, bulging, and nodal point ratio explained significant variance in perceptual rating (R2 = .05, p < .001). The same factors resulted in generally decreasing CPP, HNR, and B0-B2 and in increasing B0-B1. Of the acoustic measures, only CPP explained significant variance in perceived quality (R2 = .14, p < .001). Increasingly asymmetric amplitude of vibration or starting phase minimally altered vocal function or voice quality. Conclusion Asymmetries of adduction, bulging, and nodal point ratio drove acoustic measures and perception in the current study, whereas asymmetric amplitude of vibration and starting phase demonstrated minimal influence on the acoustic signal or voice quality. PMID:24845730

A study on locating the sonic source of sinusoidal magneto-acoustic signals using a vector method.

PubMed

Zhang, Shunqi; Zhou, Xiaoqing; Ma, Ren; Yin, Tao; Liu, Zhipeng

2015-01-01

Methods based on the magnetic-acoustic effect are of great significance in studying the electrical imaging properties of biological tissues and currents. The continuous wave method, which is commonly used, can only detect the current amplitude without the sound source position. Although the pulse mode adopted in magneto-acoustic imaging can locate the sonic source, the low measuring accuracy and low SNR has limited its application. In this study, a vector method was used to solve and analyze the magnetic-acoustic signal based on the continuous sine wave mode. This study includes theory modeling of the vector method, simulations to the line model, and experiments with wire samples to analyze magneto-acoustic (MA) signal characteristics. The results showed that the amplitude and phase of the MA signal contained the location information of the sonic source. The amplitude and phase obeyed the vector theory in the complex plane. This study sets a foundation for a new technique to locate sonic sources for biomedical imaging of tissue conductivity. It also aids in studying biological current detecting and reconstruction based on the magneto-acoustic effect.

Evaluation of acoustic testing techniques for spacecraft systems

NASA Technical Reports Server (NTRS)

Cockburn, J. A.

1971-01-01

External acoustic environments, structural responses, noise reductions, and the internal acoustic environments have been predicted for a typical shroud/spacecraft system during lift-off and various critical stages of flight. Spacecraft responses caused by energy transmission from the shroud via mechanical and acoustic paths have been compared and the importance of the mechanical path has been evaluated. Theoretical predictions have been compared extensively with available laboratory and in-flight measurements. Equivalent laboratory acoustic fields for simulation of shroud response during the various phases of flight have been derived and compared in detail. Techniques for varying the time-space correlations of laboratory acoustic fields have been examined, together with methods for varying the time and spatial distribution of acoustic amplitudes. Possible acoustic testing configurations for shroud/spacecraft systems have been suggested and trade-off considerations have been reviewed. The problem of simulating the acoustic environments versus simulating the structural responses has been considered and techniques for testing without the shroud installed have been discussed.

Weighting of Amplitude and Formant Rise Time Cues by School-Aged Children: A Mismatch Negativity Study

ERIC Educational Resources Information Center

Varghese, Peter; Kalashnikova, Marina; Burnham, Denis

2018-01-01

Purpose: An important skill in the development of speech perception is to apply optimal weights to acoustic cues so that phonemic information is recovered from speech with minimum effort. Here, we investigated the development of acoustic cue weighting of amplitude rise time (ART) and formant rise time (FRT) cues in children as measured by mismatch…

Acoustic spin pumping in magnetoelectric bulk acoustic wave resonator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Polzikova, N. I., E-mail: polz@cplire.ru; Alekseev, S. G.; Pyataikin, I. I.

2016-05-15

We present the generation and detection of spin currents by using magnetoelastic resonance excitation in a magnetoelectric composite high overtone bulk acoustic wave (BAW) resonator (HBAR) formed by a Al-ZnO-Al-GGG-YIG-Pt structure. Transversal BAW drives magnetization oscillations in YIG film at a given resonant magnetic field, and the resonant magneto-elastic coupling establishes the spin-current generation at the Pt/YIG interface. Due to the inverse spin Hall effect (ISHE) this BAW-driven spin current is converted to a dc voltage in the Pt layer. The dependence of the measured voltage both on magnetic field and frequency has a resonant character. The voltage is determinedmore » by the acoustic power in HBAR and changes its sign upon magnetic field reversal. We compare the experimentally observed amplitudes of the ISHE electrical field achieved by our method and other approaches to spin current generation that use surface acoustic waves and microwave resonators for ferromagnetic resonance excitation, with the theoretically expected values.« less

Startle Reflex Potentiation During Aversive Picture Viewing as an Indicator of Trait Fear

PubMed Central

Vaidyanathan, Uma; Patrick, Christopher J.; Bernat, Edward M.

2009-01-01

Measures of fearfulness and measures of psychopathy show positive and negative associations, respectively, with startle reflex potentiation during unpleasant picture viewing. We tested the hypothesis that a common bipolar trait dimension underlies these differing associations. Blink responses to noise probes were recorded during pleasant, neutral, and unpleasant pictures in 88 undergraduates assessed with a battery of self-report scales indexing fear and psychopathy/fearlessness. A significant positive association was found between an omnibus index of fear, consisting of scores on the first component from a PCA of these various scales, and startle potentiation during aversive picture viewing. This association was most robust, across participants overall and within gender subgroups, for scenes that were most directly threatening. Implications for psychophysiological research on individual differences and psychopathology are discussed. PMID:19055499

Tactile objects based on an amplitude disturbed diffraction pattern method

NASA Astrophysics Data System (ADS)

Liu, Yuan; Nikolovski, Jean-Pierre; Mechbal, Nazih; Hafez, Moustapha; Vergé, Michel

2009-12-01

Tactile sensing is becoming widely used in human-computer interfaces. Recent advances in acoustic approaches demonstrated the possibilities to transform ordinary solid objects into interactive interfaces. This letter proposes a static finger contact localization process using an amplitude disturbed diffraction pattern method. The localization method is based on the following physical phenomenon: a finger contact modifies the energy distribution of acoustic wave in a solid; these variations depend on the wave frequency and the contact position. The presented method first consists of exciting the object with an acoustic signal with plural frequency components. In a second step, a measured acoustic signal is compared with prerecorded values to deduce the contact position. This position is then used for human-machine interaction (e.g., finger tracking on computer screen). The selection of excitation signals is discussed and a frequency choice criterion based on contrast value is proposed. Tests on a sandwich plate (liquid crystal display screen) prove the simplicity and easiness to apply the process in various solids.

Amplitude-dependent internal friction, hysteretic nonlinearity, and nonlinear oscillations in a magnesite resonator.

PubMed

Nazarov, V E; Kolpakov, A B; Radostin, A V

2012-07-01

The results of experimental and theoretical studies of low-frequency nonlinear acoustics phenomena (amplitude-dependent loss, resonance frequency shifts, and a generation of second and third harmonics) in a magnesite rod resonator are presented. Acceleration and velocity oscillograms of vibrations of the free boundary of the resonator caused by harmonic excitations were measured and analyzed. A theoretical description of the observed amplitude dependences was carried out within the framework of the phenomenological state equations that contain either of the two types of hysteretic nonlinearity (elastic and inelastic). The type of hysteresis and parameters of acoustic nonlinearity of magnesite were established from comparing the experimental measurements with the theoretical dependences. The values of the parameters were anomalously high even when compared to those of other strongly nonlinear polycrystalline materials such as granite, marble, limestone, sandstone, etc.

Light Diffraction by Large Amplitude Ultrasonic Waves in Liquids

NASA Technical Reports Server (NTRS)

Adler, Laszlo; Cantrell, John H.; Yost, William T.

2016-01-01

Light diffraction from ultrasound, which can be used to investigate nonlinear acoustic phenomena in liquids, is reported for wave amplitudes larger than that typically reported in the literature. Large amplitude waves result in waveform distortion due to the nonlinearity of the medium that generates harmonics and produces asymmetries in the light diffraction pattern. For standing waves with amplitudes above a threshold value, subharmonics are generated in addition to the harmonics and produce additional diffraction orders of the incident light. With increasing drive amplitude above the threshold a cascade of period-doubling subharmonics are generated, terminating in a region characterized by a random, incoherent (chaotic) diffraction pattern. To explain the experimental results a toy model is introduced, which is derived from traveling wave solutions of the nonlinear wave equation corresponding to the fundamental and second harmonic standing waves. The toy model reduces the nonlinear partial differential equation to a mathematically more tractable nonlinear ordinary differential equation. The model predicts the experimentally observed cascade of period-doubling subharmonics terminating in chaos that occurs with increasing drive amplitudes above the threshold value. The calculated threshold amplitude is consistent with the value estimated from the experimental data.

Amplitude-modulation detection by gerbils in reverberant sound fields.

PubMed

Lingner, Andrea; Kugler, Kathrin; Grothe, Benedikt; Wiegrebe, Lutz

2013-08-01

Reverberation can dramatically reduce the depth of amplitude modulations which are critical for speech intelligibility. Psychophysical experiments indicate that humans' sensitivity to amplitude modulation in reverberation is better than predicted from the acoustic modulation depth at the receiver position. Electrophysiological studies on reverberation in rabbits highlight the contribution of neurons sensitive to interaural correlation. Here, we use a prepulse-inhibition paradigm to quantify the gerbils' amplitude modulation threshold in both anechoic and reverberant virtual environments. Data show that prepulse inhibition provides a reliable method for determining the gerbils' AM sensitivity. However, we find no evidence for perceptual restoration of amplitude modulation in reverberation. Instead, the deterioration of AM sensitivity in reverberant conditions can be quantitatively explained by the reduced modulation depth at the receiver position. We suggest that the lack of perceptual restoration is related to physical properties of the gerbil's ear input signals and inner-ear processing as opposed to shortcomings of their binaural neural processing. Copyright © 2013 Elsevier B.V. All rights reserved.

Development of the Acoustically Evoked Behavioral Response in Larval Plainfin Midshipman Fish, Porichthys notatus

PubMed Central

Alderks, Peter W.; Sisneros, Joseph A.

2013-01-01

The ontogeny of hearing in fishes has become a major interest among bioacoustics researchers studying fish behavior and sensory ecology. Most fish begin to detect acoustic stimuli during the larval stage which can be important for navigation, predator avoidance and settlement, however relatively little is known about the hearing capabilities of larval fishes. We characterized the acoustically evoked behavioral response (AEBR) in the plainfin midshipman fish, Porichthys notatus, and used this innate startle-like response to characterize this species' auditory capability during larval development. Age and size of larval midshipman were highly correlated (r2 = 0.92). The AEBR was first observed in larvae at 1.4 cm TL. At a size ≥1.8 cm TL, all larvae responded to a broadband stimulus of 154 dB re1 µPa or −15.2 dB re 1 g (z-axis). Lowest AEBR thresholds were 140–150 dB re 1 µPa or −33 to −23 dB re 1 g for frequencies below 225 Hz. Larval fish with size ranges of 1.9–2.4 cm TL had significantly lower best evoked frequencies than the other tested size groups. We also investigated the development of the lateral line organ and its function in mediating the AEBR. The lateral line organ is likely involved in mediating the AEBR but not necessary to evoke the startle-like response. The midshipman auditory and lateral line systems are functional during early development when the larvae are in the nest and the auditory system appears to have similar tuning characteristics throughout all life history stages. PMID:24340003

Development of the acoustically evoked behavioral response in larval plainfin midshipman fish, Porichthys notatus.

PubMed

Alderks, Peter W; Sisneros, Joseph A

2013-01-01

The ontogeny of hearing in fishes has become a major interest among bioacoustics researchers studying fish behavior and sensory ecology. Most fish begin to detect acoustic stimuli during the larval stage which can be important for navigation, predator avoidance and settlement, however relatively little is known about the hearing capabilities of larval fishes. We characterized the acoustically evoked behavioral response (AEBR) in the plainfin midshipman fish, Porichthys notatus, and used this innate startle-like response to characterize this species' auditory capability during larval development. Age and size of larval midshipman were highly correlated (r(2) = 0.92). The AEBR was first observed in larvae at 1.4 cm TL. At a size ≥ 1.8 cm TL, all larvae responded to a broadband stimulus of 154 dB re1 µPa or -15.2 dB re 1 g (z-axis). Lowest AEBR thresholds were 140-150 dB re 1 µPa or -33 to -23 dB re 1 g for frequencies below 225 Hz. Larval fish with size ranges of 1.9-2.4 cm TL had significantly lower best evoked frequencies than the other tested size groups. We also investigated the development of the lateral line organ and its function in mediating the AEBR. The lateral line organ is likely involved in mediating the AEBR but not necessary to evoke the startle-like response. The midshipman auditory and lateral line systems are functional during early development when the larvae are in the nest and the auditory system appears to have similar tuning characteristics throughout all life history stages.

Single-point nonlinearity indicators for the propagation of high-amplitude acoustic signals

NASA Astrophysics Data System (ADS)

Falco, Lauren E.

. Both single-frequency signals and band-limited noise were used as sources, and waveforms were recorded at all four propagation distances. The second set of data was obtained at the model-scale jet facility at the University of Mississippi's National Center for Physical Acoustics. A computer controlled microphone boom was constructed to hold an array of six microphones. The array was rotated about the presumed location of the acoustic source center (4 jet diameters downstream of the nozzle exit), and two stationary microphones were mounted on the walls. Measurements were made for several jet conditions; data presented here represent Mach 0.85 and Mach 2 conditions. Application of the four candidate nonlinearity indicators to the experimental data reveals that each indicator has advantages and disadvantages. Qneg/Qpos does not detect the presence of shocks as postulated, but it does conform to expectations in the shock-free region and support the use of Qpos as an indicator. The main advantage of Qpos/p3rms is that it can be used for band-limited measurements. Increased indicator values are seen for signals with higher source frequencies and amplitudes that are expected to undergo stronger nonlinear evolution. However, no physical meaning can yet be derived from the numerical value of the indicator. The spectral Gol'dberg number Gammas is the most promising of the candidate quantities. It has the ability to indicate the direction of nonlinear energy transfer as well as provide a comparison between the strengths of linear and nonlinear effects. These attributes allow it to be used to qualitatively predict the evolution of a spectrum. The coherence indicator gammaQ also specifies the direction of nonlinear energy transfer, but its numerical value holds less meaning. However, it is bounded between -1 and 1, so values near zero denote very weak or no nonlinearity, and values near -1 or 1 denote strong nonlinearity. Further, because it is bounded, it does not become unstable

An approach for estimating acoustic power in a pulse tube cryocooler

NASA Astrophysics Data System (ADS)

Jiang, Xiao; Qiu, Limin; Duan, Chaoxiang; You, Xiaokuan; Zhi, Xiaoqin

2017-10-01

Acoustic power at the cold end of regenerator is the measure of gross cooling capacity for a pulse tube cryocooler (PTC), which cannot be measured directly. Conventionally, the acoustic power can only be derived from the measurement of velocity, pressure and their phase angle, which is still a challenge for an oscillating flow at cryogenic temperatures. A new method is proposed for estimating the acoustic power, which takes use of the easily measurable parameters, such as the pressure and temperature, instead of the velocity and phase angle between the pressure and velocity at cryogenic temperatures. The ratio of acoustic powers at the both ends of isothermal components, like regenerator, heat exchangers, can be conveniently evaluated by using the ratio of pressure amplitudes and the local temperatures. The ratio of acoustic powers at the both ends of adiabatic components, like transfer line and pulse tube, is obtained by using the ratio of pressure amplitudes. Accuracy of the approach for evaluating the acoustic power for the regenerator is analyzed by comparing the results with those from REGEN 3.3 and references. For the cold end temperature range of 40-80 K, the deviation is less than 5% if the phase angle at the cold end of regenerator is around -30°. The simple method benefits estimating the acoustic power and optimizing the PTC performance without interfering the cryogenic flow field.

Correlation between average frequency and RA value (rise time/amplitude) for crack classification of reinforced concrete beam using acoustic emission technique

NASA Astrophysics Data System (ADS)

Noorsuhada, M. N.; Abdul Hakeem, Z.; Soffian Noor, M. S.; Noor Syafeekha, M. S.; Azmi, I.

2017-12-01

Health monitoring of structures during their service life become a vital thing as it provides crucial information regarding the performance and condition of the structures. Acoustic emission (AE) is one of the non-destructive techniques (NDTs) that could be used to monitor the performance of the structures. Reinforced concrete (RC) beam associated with AE monitoring was monotonically loaded to failure under three-point loading. Correlation between average frequency and RA value (rise time / amplitude) was computed. The relationship was established to classify the crack types that propagated in the RC beam. The crack was classified as tensile crack and shear crack. It was found that the relationship is well matched with the actual crack pattern that appeared on the beam surface. Hence, this relationship is useful for prediction of the crack occurrence in the beam and its performance can be determined.

Becoming the center of attention in social anxiety disorder: startle reactivity to a virtual audience during speech anticipation.

PubMed

Cornwell, Brian R; Heller, Randi; Biggs, Arter; Pine, Daniel S; Grillon, Christian

2011-07-01

A detailed understanding of how individuals diagnosed with social anxiety disorder (SAD) respond physiologically under social-evaluative threat is lacking. Our aim was to isolate the specific components of public speaking that trigger fear in vulnerable individuals and best discriminate between SAD and healthy individuals. Sixteen individuals diagnosed with SAD (DSM-IV-TR criteria) and 16 healthy individuals were enrolled in the study from December 2005 to March 2008. Subjects were asked to prepare and deliver a short speech in a virtual reality (VR) environment. The VR environment simulated standing center stage before a live audience and allowed us to gradually introduce social cues during speech anticipation. Startle eye-blink responses were elicited periodically by white noise bursts presented during anticipation, speech delivery, and recovery in VR, as well as outside VR during an initial habituation phase, and startle reactivity was measured by electromyography. Subjects rated their distress at 4 timepoints in VR using a 0-10 scale, with anchors being "not distressed" to "highly distressed." State anxiety was measured before and after VR with the Spielberger State-Trait Anxiety Inventory. Individuals with SAD reported greater distress and state anxiety than healthy individuals across the entire procedure (P values < .005). Analyses of startle reactivity revealed a robust group difference during speech anticipation in VR, specifically as audience members directed their eye gaze and turned their attention toward participants (P < .05, Bonferroni-corrected). The VR environment is sufficiently realistic to provoke fear and anxiety in individuals highly vulnerable to socially threatening situations. Individuals with SAD showed potentiated startle, indicative of a strong phasic fear response, specifically when they perceived themselves as occupying the focus of others' attention as speech time approached. Potentiated startle under social-evaluative threat indexes

Voice Tremor in Parkinson's Disease: An Acoustic Study.

PubMed

Gillivan-Murphy, Patricia; Miller, Nick; Carding, Paul

2018-01-30

Voice tremor associated with Parkinson disease (PD) has not been characterized. Its relationship with voice disability and disease variables is unknown. This study aimed to evaluate voice tremor in people with PD (pwPD) and a matched control group using acoustic analysis, and to examine correlations with voice disability and disease variables. Acoustic voice tremor analysis was completed on 30 pwPD and 28 age-gender matched controls. Voice disability (Voice Handicap Index), and disease variables of disease duration, Activities of Daily Living (Unified Parkinson's Disease Rating Scale [UPDRS II]), and motor symptoms related to PD (UPDRS III) were examined for relationship with voice tremor measures. Voice tremor was detected acoustically in pwPD and controls with similar frequency. PwPD had a statistically significantly higher rate of amplitude tremor (Hz) than controls (P = 0.001). Rate of amplitude tremor was negatively and significantly correlated with UPDRS III total score (rho -0.509). For pwPD, the magnitude and periodicity of acoustic tremor was higher than for controls without statistical significance. The magnitude of frequency tremor (Mftr%) was positively and significantly correlated with disease duration (rho 0.463). PwPD had higher Voice Handicap Index total, functional, emotional, and physical subscale scores than matched controls (P < 0.001). Voice disability did not correlate significantly with acoustic voice tremor measures. Acoustic analysis enhances understanding of PD voice tremor characteristics, its pathophysiology, and its relationship with voice disability and disease symptomatology. Copyright © 2018 The Voice Foundation. All rights reserved.

Assessing the Comprehensive Soldier Fitness Program: Measuring Startle Response and Prepulse Inhibition

DTIC Science & Technology

2011-04-01

increase PPI, but dopamine agonists can have the opposite effect by reducing PPI. Fortunately, caffeine appears to have no significant effect on PPI...violent behavior, and sexual risk behavior. Landis, C., & Hunt, W.A. (1939). The Startle Pattern. New York: Farrar. An example of early research on

Fine manipulation of sound via lossy metamaterials with independent and arbitrary reflection amplitude and phase.

PubMed

Zhu, Yifan; Hu, Jie; Fan, Xudong; Yang, Jing; Liang, Bin; Zhu, Xuefeng; Cheng, Jianchun

2018-04-24

The fine manipulation of sound fields is critical in acoustics yet is restricted by the coupled amplitude and phase modulations in existing wave-steering metamaterials. Commonly, unavoidable losses make it difficult to control coupling, thereby limiting device performance. Here we show the possibility of tailoring the loss in metamaterials to realize fine control of sound in three-dimensional (3D) space. Quantitative studies on the parameter dependence of reflection amplitude and phase identify quasi-decoupled points in the structural parameter space, allowing arbitrary amplitude-phase combinations for reflected sound. We further demonstrate the significance of our approach for sound manipulation by producing self-bending beams, multifocal focusing, and a single-plane two-dimensional hologram, as well as a multi-plane 3D hologram with quality better than the previous phase-controlled approach. Our work provides a route for harnessing sound via engineering the loss, enabling promising device applications in acoustics and related fields.

A comparison of auditory evoked potentials to acoustic beats and to binaural beats.

PubMed

Pratt, Hillel; Starr, Arnold; Michalewski, Henry J; Dimitrijevic, Andrew; Bleich, Naomi; Mittelman, Nomi

2010-04-01

The purpose of this study was to compare cortical brain responses evoked by amplitude modulated acoustic beats of 3 and 6 Hz in tones of 250 and 1000 Hz with those evoked by their binaural beats counterparts in unmodulated tones to indicate whether the cortical processes involved differ. Event-related potentials (ERPs) were recorded to 3- and 6-Hz acoustic and binaural beats in 2000 ms duration 250 and 1000 Hz tones presented with approximately 1 s intervals. Latency, amplitude and source current density estimates of ERP components to beats-evoked oscillations were determined and compared across beat types, beat frequencies and base (carrier) frequencies. All stimuli evoked tone-onset components followed by oscillations corresponding to the beat frequency, and a subsequent tone-offset complex. Beats-evoked oscillations were higher in amplitude in response to acoustic than to binaural beats, to 250 than to 1000 Hz base frequency and to 3 Hz than to 6 Hz beat frequency. Sources of the beats-evoked oscillations across all stimulus conditions located mostly to left temporal lobe areas. Differences between estimated sources of potentials to acoustic and binaural beats were not significant. The perceptions of binaural beats involve cortical activity that is not different than acoustic beats in distribution and in the effects of beat- and base frequency, indicating similar cortical processing. Copyright 2010 Elsevier B.V. All rights reserved.

MitoPark mice, an animal model of Parkinson's disease, show enhanced prepulse inhibition of acoustic startle and no loss of gating in response to the adenosine A(2A) antagonist SCH 412348.

PubMed

Grauer, Steven M; Hodgson, Robert; Hyde, Lynn A

2014-04-01

Psychoses are debilitating side effects associated with current dopaminergic treatments for Parkinson's disease (PD). Prepulse inhibition (PPI), in which a non-startling stimulus reduces startle response to a subsequent startle-eliciting stimulus, is important in filtering out extraneous sensory stimuli. PPI deficits induced by dopamine agonists can model symptoms of psychosis. Adenosine A(2A) receptor antagonists, being developed as novel PD treatments, indirectly modulate dopamine signaling in the basal ganglia and may have an improved psychosis profile which could be detected using the PPI model. The aims of this study is to characterize PPI in MitoPark mice, which exhibit progressive loss of dopamine signaling and develop a Parkinson-like motor phenotype, and assess standard and novel PD treatment effects on PPI in MitoPark mice, which more closely mimic the basal ganglia dopamine status of PD patients. MitoPark mice displayed enhanced PPI as dopamine tone decreased with age, consistent with studies in intact mice that show enhanced PPI in response to dopamine antagonists. Paradoxically, older MitoParks were more sensitive to PPI disruption when challenged with dopamine agonists such as apomorphine or pramipexole. Alternatively, SCH 412348, an adenosine A(2A) antagonist, did not disrupt PPI in MitoPark mice at doses that normalized hypoactivity. Use of MitoPark mice in the PPI assay to assess the potential for PD treatment to produce psychoses likely represents a more disease-relevant model. SCH 412348 does not differentially disrupt PPI as do dopamine agonists, perhaps indicative of an improved psychosis profile of adenosine A(2A) antagonists, even in PD patients with decreased dopamine tone in the basal ganglia.

The emotional startle effect is disrupted by a concurrent working memory task.

PubMed

King, Rosemary; Schaefer, Alexandre

2011-02-01

Working memory (WM) processes are often thought to play an important role in the cognitive regulation of negative emotions. However, little is known about how they influence emotional processing. We report two experiments that tested whether a concurrent working memory task could modulate the emotional startle eyeblink effect, a well-known index of emotional processing. In both experiments, emotionally negative and neutral pictures were viewed in two conditions: a "cognitive load" (CL) condition, in which participants had to actively maintain information in working memory (WM) while viewing the pictures, and a control "no load" (NL) condition. Picture-viewing instructions were identical across CL and NL. In both experiments, results showed a significant reduction of the emotional modulation of the startle eyeblink reflex in the CL condition compared to the NL condition. These findings suggest that a concurrent WM task disrupts emotional processing even when participants are directing visual focus on emotionally relevant information. Copyright © 2010 Society for Psychophysiological Research.

Amplitude interpretation and visualization of three-dimensional reflection data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Enachescu, M.E.

1994-07-01

Digital recording and processing of modern three-dimensional surveys allow for relative good preservation and correct spatial positioning of seismic reflection amplitude. A four-dimensional seismic reflection field matrix R (x,y,t,A), which can be computer visualized (i.e., real-time interactively rendered, edited, and animated), is now available to the interpreter. The amplitude contains encoded geological information indirectly related to lithologies and reservoir properties. The magnitude of the amplitude depends not only on the acoustic impedance contrast across a boundary, but is also strongly affected by the shape of the reflective boundary. This allows the interpreter to image subtle tectonic and structural elements notmore » obvious on time-structure maps. The use of modern workstations allows for appropriate color coding of the total available amplitude range, routine on-screen time/amplitude extraction, and late display of horizon amplitude maps (horizon slices) or complex amplitude-structure spatial visualization. Stratigraphic, structural, tectonic, fluid distribution, and paleogeographic information are commonly obtained by displaying the amplitude variation A = A(x,y,t) associated with a particular reflective surface or seismic interval. As illustrated with several case histories, traditional structural and stratigraphic interpretation combined with a detailed amplitude study generally greatly enhance extraction of subsurface geological information from a reflection data volume. In the context of three-dimensional seismic surveys, the horizon amplitude map (horizon slice), amplitude attachment to structure and [open quotes]bright clouds[close quotes] displays are very powerful tools available to the interpreter.« less

Acoustical tweezers using single spherically focused piston, X-cut, and Gaussian beams.

PubMed

Mitri, Farid G

2015-10-01

Partial-wave series expansions (PWSEs) satisfying the Helmholtz equation in spherical coordinates are derived for circular spherically focused piston (i.e., apodized by a uniform velocity amplitude normal to its surface), X-cut (i.e., apodized by a velocity amplitude parallel to the axis of wave propagation), and Gaussian (i.e., apodized by a Gaussian distribution of the velocity amplitude) beams. The Rayleigh-Sommerfeld diffraction integral and the addition theorems for the Legendre and spherical wave functions are used to obtain the PWSEs assuming weakly focused beams (with focusing angle α ⩽ 20°) in the Fresnel-Kirchhoff (parabolic) approximation. In contrast with previous analytical models, the derived expressions allow computing the scattering and acoustic radiation force from a sphere of radius a without restriction to either the Rayleigh (a ≪ λ, where λ is the wavelength of the incident radiation) or the ray acoustics (a ≫λ) regimes. The analytical formulations are valid for wavelengths largely exceeding the radius of the focused acoustic radiator, when the viscosity of the surrounding fluid can be neglected, and when the sphere is translated along the axis of wave propagation. Computational results illustrate the analysis with particular emphasis on the sphere's elastic properties and the axial distance to the center of the concave surface, with close connection of the emergence of negative trapping forces. Potential applications are in single-beam acoustical tweezers, acoustic levitation, and particle manipulation.

The interaction of acoustic and linguistic grouping cues in auditory object formation

NASA Astrophysics Data System (ADS)

Shapley, Kathy; Carrell, Thomas

2005-09-01

One of the earliest explanations for good speech intelligibility in poor listening situations was context [Miller et al., J. Exp. Psychol. 41 (1951)]. Context presumably allows listeners to group and predict speech appropriately and is known as a top-down listening strategy. Amplitude comodulation is another mechanism that has been shown to improve sentence intelligibility. Amplitude comodulation provides acoustic grouping information without changing the linguistic content of the desired signal [Carrell and Opie, Percept. Psychophys. 52 (1992); Hu and Wang, Proceedings of ICASSP-02 (2002)] and is considered a bottom-up process. The present experiment investigated how amplitude comodulation and semantic information combined to improve speech intelligibility. Sentences with high- and low-predictability word sequences [Boothroyd and Nittrouer, J. Acoust. Soc. Am. 84 (1988)] were constructed in two different formats: time-varying sinusoidal sentences (TVS) and reduced-channel sentences (RC). The stimuli were chosen because they minimally represent the traditionally defined speech cues and therefore emphasized the importance of the high-level context effects and low-level acoustic grouping cues. Results indicated that semantic information did not influence intelligibility levels of TVS and RC sentences. In addition amplitude modulation aided listeners' intelligibility scores in the TVS condition but hindered listeners' intelligibility scores in the RC condition.

Reduced-Order Models for Acoustic Response Prediction

DTIC Science & Technology

2011-07-01

pressure on the surface of a flight vehicle skin can have complex amplitude and phase content. However, the pressure is often assumed to be a plane ...were used in the simulations. The input spectrum excited the first two symmetric bending modes of the beam . These two modes occurred at 79.0 Hz...the modal amplitude vector and  is a truncated set of uncoupled, mass normalized, mode shapes for the exterior acoustic domain. There are two

Startle response memory and hippocampal changes in adult zebrafish pharmacologically-induced to exhibit anxiety/depression-like behaviors.

PubMed

Pittman, Julian T; Lott, Chad S

2014-01-17

Zebrafish (Danio rerio) are rapidly becoming a popular animal model for neurobehavioral and psychopharmacological research. While startle testing is a well-established assay to investigate anxiety-like behaviors in different species, screening of the startle response and its habituation in zebrafish is a new direction of translational biomedical research. This study focuses on a novel behavioral protocol to assess a tapping-induced startle response and its habituation in adult zebrafish that have been pharmacologically-induced to exhibit anxiety/depression-like behaviors. We demonstrated that zebrafish exhibit robust learning performance in a task adapted from the mammalian literature, a modified plus maze, and showed that ethanol and fluoxetine impair memory performance in this maze when administered after training at a dose that does not impair motor function, however, leads to significant upregulation of hippocampal serotoninergic neurons. These results suggest that the maze associative learning paradigm has face and construct validity and that zebrafish may become a translationally relevant study species for the analysis of the mechanisms of learning and memory changes associated with psychopharmacological treatment of anxiety/depression. © 2013.

Stimulated Parametric Decay of Large Amplitude Alfv'en waves in the Large Plasma Device (LaPD)

NASA Astrophysics Data System (ADS)

Dorfman, S.; Carter, T.; Pribyl, P.; Tripathi, S. K. P.; van Compernolle, B.; Vincena, S.

2012-10-01

Alfv'en waves, the fundamental mode of magnetized plasmas, are ubiquitous in lab and space. While the linear behaviour of these waves has been extensively studied, non-linear effects are important in many real systems. In particular, a parametric decay process in which a large amplitude Alfv'en wave decays into an ion acoustic wave and backward propagating Alfv'en wave may be key to the spectrum of solar wind turbulence. The present laboratory experiments aim to stimulate this process by launching counter-propagating Alfv'en waves from antennas placed at either end of the Large Plasma Device (LaPD). The resulting beat response has many properties consistent with an ion acoustic wave including: 1) The beat amplitude peaks when the frequency difference between the two Alfv'en waves is near the value predicted by Alfv'en-ion acoustic wave coupling. 2) This peak beat frequency scales with antenna and plasma parameters as predicted by three wave matching. 3) The beat amplitude peaks at the same location as the magnetic field from the Alfv'en waves. 4) The beat wave is carried by the ions and propagates in the direction of the higher-frequency Alfv'en wave. Strong damping observed after the pump Alfv'en waves are turned off is under investigation.

Acoustic method for levitation of small living animals

NASA Astrophysics Data System (ADS)

Xie, W. J.; Cao, C. D.; Lü, Y. J.; Hong, Z. Y.; Wei, B.

2006-11-01

Ultrasonic levitation of some small living animals such as ant, ladybug, and young fish has been achieved with a single-axis acoustic levitator. The vitality of ant and ladybug is not evidently influenced during the acoustic levitation, whereas that of the young fish is reduced because of the inadequacy of water supply. Numerical analysis shows that the sound pressures on the ladybug's surface almost reach the incident pressure amplitude p0 due to sound scattering. It is estimated that 99.98% of the acoustic energy is reflected away from the ladybug. The acoustic radiation pressure pa on the ladybug's surface is only 1%-3% of p0, which plays a compression role on the central region and a suction role on the peripheral region.

Dynamics of levitated objects in acoustic vortex fields.

PubMed

Hong, Z Y; Yin, J F; Zhai, W; Yan, N; Wang, W L; Zhang, J; Drinkwater, Bruce W

2017-08-02

Acoustic levitation in gaseous media provides a tool to process solid and liquid materials without the presence of surfaces such as container walls and hence has been used widely in chemical analysis, high-temperature processing, drop dynamics and bioreactors. To date high-density objects can only be acoustically levitated in simple standing-wave fields. Here we demonstrate the ability of a small number of peripherally placed sources to generate acoustic vortex fields and stably levitate a wide range of liquid and solid objects. The forces exerted by these acoustic vortex fields on a levitated water droplet are observed to cause a controllable deformation of the droplet and/or oscillation along the vortex axis. Orbital angular momentum transfer is also shown to rotate a levitated object rapidly and the rate of rotation can be controlled by the source amplitude. We expect this research can increase the diversity of acoustic levitation and expand the application of acoustic vortices.

Coherent acoustic phonons in nanostructures

NASA Astrophysics Data System (ADS)

Dekorsy, T.; Taubert, R.; Hudert, F.; Bartels, A.; Habenicht, A.; Merkt, F.; Leiderer, P.; Köhler, K.; Schmitz, J.; Wagner, J.

2008-02-01

Phonons are considered as a most important origin of scattering and dissipation for electronic coherence in nanostructures. The generation of coherent acoustic phonons with femtosecond laser pulses opens the possibility to control phonon dynamics in amplitude and phase. We demonstrate a new experimental technique based on two synchronized femtosecond lasers with GHz repetition rate to study the dynamics of coherently generated acoustic phonons in semiconductor heterostructures with high sensitivity. High-speed synchronous optical sampling (ASOPS) enables to scan a time-delay of 1 ns with 100 fs time resolution with a frequency in the kHz range without a moving part in the set-up. We investigate the dynamics of coherent zone-folded acoustic phonons in semiconductor superlattices (GaAs/AlAs and GaSb/InAs) and of coherent vibration of metallic nanostructures of non-spherical shape using ASOPS.

Pattern-formation under acoustic driving forces

NASA Astrophysics Data System (ADS)

Valverde, Jose Manuel

2015-07-01

Chemical and metallurgical processes enhanced by high intensity acoustic waves, thermoacoustic engines and refrigerators, fuel rods in nuclear reactors, heat exchanger tubes, offshore and vibrating structures, solar thermal collectors, acoustic levitators, microfluidic devices, cycling, musical acoustics, blood flow through veins/arteries, hearing in the mammalian ear, carbon nanotube loudspeakers, etc. The evolution of a myriad of processes involving the oscillation of viscous fluids in the presence of solid boundaries is up to a certain extent influenced by acoustic streaming. In addition to the sound field, viscous energy dissipation at the fluid-solid boundary causes a time-independent fluid circulation, which can lead to a significant enhancement of heat, mass and momentum transfer at large oscillation amplitudes. A particularly relevant phenomenon that can be notably affected by acoustic streaming is the promotion of sound waves by temperature gradients or viceversa (thermoacoustics), which is at the basis of potentially efficient and environmental friendly engines and refrigerators that have attracted a renewed interest in the last years. In the present manuscript, historical developments and the underlying basic physics behind acoustic streaming and thermoacoustics are reviewed from an unifying perspective.

Laser-nucleated acoustic cavitation in focused ultrasound.

PubMed

Gerold, Bjoern; Kotopoulis, Spiros; McDougall, Craig; McGloin, David; Postema, Michiel; Prentice, Paul

2011-04-01

Acoustic cavitation can occur in therapeutic applications of high-amplitude focused ultrasound. Studying acoustic cavitation has been challenging, because the onset of nucleation is unpredictable. We hypothesized that acoustic cavitation can be forced to occur at a specific location using a laser to nucleate a microcavity in a pre-established ultrasound field. In this paper we describe a scientific instrument that is dedicated to this outcome, combining a focused ultrasound transducer with a pulsed laser. We present high-speed photographic observations of laser-induced cavitation and laser-nucleated acoustic cavitation, at frame rates of 0.5×10(6) frames per second, from laser pulses of energy above and below the optical breakdown threshold, respectively. Acoustic recordings demonstrated inertial cavitation can be controllably introduced to the ultrasound focus. This technique will contribute to the understanding of cavitation evolution in focused ultrasound including for potential therapeutic applications. © 2011 American Institute of Physics

Effect of magnetic quantization on ion acoustic waves ultra-relativistic dense plasma

NASA Astrophysics Data System (ADS)

Javed, Asif; Rasheed, A.; Jamil, M.; Siddique, M.; Tsintsadze, N. L.

2017-11-01

In this paper, we have studied the influence of magnetic quantization of orbital motion of the electrons on the profile of linear and nonlinear ion-acoustic waves, which are propagating in the ultra-relativistic dense magneto quantum plasmas. We have employed both Thomas Fermi and Quantum Magneto Hydrodynamic models (along with the Poisson equation) of quantum plasmas. To investigate the large amplitude nonlinear structure of the acoustic wave, Sagdeev-Pseudo-Potential approach has been adopted. The numerical analysis of the linear dispersion relation and the nonlinear acoustic waves has been presented by drawing their graphs that highlight the effects of plasma parameters on these waves in both the linear and the nonlinear regimes. It has been noticed that only supersonic ion acoustic solitary waves can be excited in the above mentioned quantum plasma even when the value of the critical Mach number is less than unity. Both width and depth of Sagdeev potential reduces on increasing the magnetic quantization parameter η. Whereas the amplitude of the ion acoustic soliton reduces on increasing η, its width appears to be directly proportional to η. The present work would be helpful to understand the excitation of nonlinear ion-acoustic waves in the dense astrophysical environments such as magnetars and in intense-laser plasma interactions.

Acoustic reflex patterns in amyotrophic lateral sclerosis.

PubMed

Canale, Andrea; Albera, Roberto; Lacilla, Michelangelo; Canosa, Antonio; Albera, Andrea; Sacco, Francesca; Chiò, Adriano; Calvo, Andrea

2017-02-01

The aim of the study is to investigate acoustic reflex testing in amyotrophic lateral sclerosis patients. Amplitude, latency, and rise time of stapedial reflex were recorded for 500 and 1000 Hz contralateral stimulus. Statistical analysis was performed by the Wilcoxon test and the level of significance was set at 5 %. Fifty-one amyotrophic lateral sclerosis patients and ten sex- and age-matched control subjects were studied. Patients were further divided in two groups: amyotrophic lateral sclerosis-bulbar (38 cases, with bulbar signs at evaluation) and amyotrophic lateral sclerosis-spinal (13 cases, without bulbar signs at evaluation). Stapedial reflex was present in all patients. There was a statistically significant difference in the mean amplitude, latency, and rise time between the amyotrophic lateral sclerosis patients as compared with the controls. Amplitude was lower in both the amyotrophic lateral sclerosis-bulbar and the amyotrophic lateral sclerosis-spinal patients than in the controls (p < 0.05) and rise time was longer in both patient groups compared with the controls (p < 0.05). These results confirm the presence of abnormal acoustic reflex patterns in amyotrophic lateral sclerosis cases with bulbar signs and, moreover, suggesting a possible subclinical involvement of the stapedial motor neuron even in amyotrophic lateral sclerosis-spinal patients. Amplitude and rise time seem to be good sensitive parameters for investigating subclinical bulbar involvement.

Amplitude modulation detection by human listeners in sound fields.

PubMed

Zahorik, Pavel; Kim, Duck O; Kuwada, Shigeyuki; Anderson, Paul W; Brandewie, Eugene; Srinivasan, Nirmal

2011-10-01

The temporal modulation transfer function (TMTF) approach allows techniques from linear systems analysis to be used to predict how the auditory system will respond to arbitrary patterns of amplitude modulation (AM). Although this approach forms the basis for a standard method of predicting speech intelligibility based on estimates of the acoustical modulation transfer function (MTF) between source and receiver, human sensitivity to AM as characterized by the TMTF has not been extensively studied under realistic listening conditions, such as in reverberant sound fields. Here, TMTFs (octave bands from 2 - 512 Hz) were obtained in 3 listening conditions simulated using virtual auditory space techniques: diotic, anechoic sound field, reverberant room sound field. TMTFs were then related to acoustical MTFs estimated using two different methods in each of the listening conditions. Both diotic and anechoic data were found to be in good agreement with classic results, but AM thresholds in the reverberant room were lower than predictions based on acoustical MTFs. This result suggests that simple linear systems techniques may not be appropriate for predicting TMTFs from acoustical MTFs in reverberant sound fields, and may be suggestive of mechanisms that functionally enhance modulation during reverberant listening.

Acoustic-noise-optimized diffusion-weighted imaging.

PubMed

Ott, Martin; Blaimer, Martin; Grodzki, David M; Breuer, Felix A; Roesch, Julie; Dörfler, Arnd; Heismann, Björn; Jakob, Peter M

2015-12-01

This work was aimed at reducing acoustic noise in diffusion-weighted MR imaging (DWI) that might reach acoustic noise levels of over 100 dB(A) in clinical practice. A diffusion-weighted readout-segmented echo-planar imaging (EPI) sequence was optimized for acoustic noise by utilizing small readout segment widths to obtain low gradient slew rates and amplitudes instead of faster k-space coverage. In addition, all other gradients were optimized for low slew rates. Volunteer and patient imaging experiments were conducted to demonstrate the feasibility of the method. Acoustic noise measurements were performed and analyzed for four different DWI measurement protocols at 1.5T and 3T. An acoustic noise reduction of up to 20 dB(A) was achieved, which corresponds to a fourfold reduction in acoustic perception. The image quality was preserved at the level of a standard single-shot (ss)-EPI sequence, with a 27-54% increase in scan time. The diffusion-weighted imaging technique proposed in this study allowed a substantial reduction in the level of acoustic noise compared to standard single-shot diffusion-weighted EPI. This is expected to afford considerably more patient comfort, but a larger study would be necessary to fully characterize the subjective changes in patient experience.

Becoming the center of attention in social anxiety disorder: Startle reactivity to a virtual audience during speech anticipation

PubMed Central

Cornwell, Brian R.; Heller, Randi; Biggs, Arter; Pine, Daniel S.; Grillon, Christian

2012-01-01

Objective A detailed understanding of how individuals diagnosed with social anxiety disorder (SAD) respond physiologically under social-evaluative threat is lacking. We aimed to isolate the specific components of public speaking that trigger fear in vulnerable individuals and best discriminate among SAD and healthy individuals. Method Sixteen individuals diagnosed with SAD and 16 healthy individuals were asked to prepare and deliver a short speech in a virtual reality (VR) environment. The VR environment simulated standing center stage before a live audience and allowed us to gradually introduce social cues during speech anticipation. Startle eye-blink responses were elicited periodically by white noise bursts presented during anticipation, speech delivery, and recovery in VR, as well as outside VR during an initial habituation phase. Results SAD individuals reported greater distress and state anxiety than healthy individuals across the entire procedure (ps < .005). Analyses of startle reactivity revealed a robust group difference during speech anticipation in VR, specifically as audience members directed their eye gaze and turned their attention toward participants (p < .05, Bonferroni corrected). Conclusions The VR environment is sufficiently realistic to provoke fear and anxiety in individuals highly vulnerable to socially threatening situations. SAD individuals showed potentiated startle, indicative of a strong phasic fear response, specifically when they perceived themselves as occupying the focus of others' attention as speech time approached. Potentiated startle under social-evaluative threat indexes SAD-related fear of negative evaluation. PMID:21034683

Modeling Nonlinear Acoustic Standing Waves in Resonators: Theory and Experiments

NASA Technical Reports Server (NTRS)

Raman, Ganesh; Li, Xiaofan; Finkbeiner, Joshua

2004-01-01

The overall goal of the cooperative research with NASA Glenn is to fundamentally understand, computationally model, and experimentally validate non-linear acoustic waves in enclosures with the ultimate goal of developing a non-contact acoustic seal. The longer term goal is to transition the Glenn acoustic seal innovation to a prototype sealing device. Lucas and coworkers are credited with pioneering work in Resonant Macrosonic Synthesis (RMS). Several Patents and publications have successfully illustrated the concept of Resonant Macrosonic Synthesis. To utilize this concept in practical application one needs to have an understanding of the details of the phenomenon and a predictive tool that can examine the waveforms produced within resonators of complex shapes. With appropriately shaped resonators one can produce un-shocked waveforms of high amplitude that would result in very high pressures in certain regions. Our goal is to control the waveforms and exploit the high pressures to produce an acoustic seal. Note that shock formation critically limits peak-to-peak pressure amplitudes and also causes excessive energy dissipation. Proper shaping of the resonator is thus critical to the use of this innovation.

Available pressure amplitude of linear compressor based on phasor triangle model

NASA Astrophysics Data System (ADS)

Duan, C. X.; Jiang, X.; Zhi, X. Q.; You, X. K.; Qiu, L. M.

2017-12-01

The linear compressor for cryocoolers possess the advantages of long-life operation, high efficiency, low vibration and compact structure. It is significant to study the match mechanisms between the compressor and the cold finger, which determines the working efficiency of the cryocooler. However, the output characteristics of linear compressor are complicated since it is affected by many interacting parameters. The existing matching methods are simplified and mainly focus on the compressor efficiency and output acoustic power, while neglecting the important output parameter of pressure amplitude. In this study, a phasor triangle model basing on analyzing the forces of the piston is proposed. It can be used to predict not only the output acoustic power, the efficiency, but also the pressure amplitude of the linear compressor. Calculated results agree well with the measurement results of the experiment. By this phasor triangle model, the theoretical maximum output pressure amplitude of the linear compressor can be calculated simply based on a known charging pressure and operating frequency. Compared with the mechanical and electrical model of the linear compressor, the new model can provide an intuitionistic understanding on the match mechanism with faster computational process. The model can also explain the experimental phenomenon of the proportional relationship between the output pressure amplitude and the piston displacement in experiments. By further model analysis, such phenomenon is confirmed as an expression of the unmatched design of the compressor. The phasor triangle model may provide an alternative method for the compressor design and matching with the cold finger.

Subharmonic generation, chaos, and subharmonic resurrection in an acoustically driven fluid-filled cavity.

PubMed

Cantrell, John H; Adler, Laszlo; Yost, William T

2015-02-01

Traveling wave solutions of the nonlinear acoustic wave equation are obtained for the fundamental and second harmonic resonances of a fluid-filled cavity. The solutions lead to the development of a non-autonomous toy model for cavity oscillations. Application of the Melnikov method to the model equation predicts homoclinic bifurcation of the Smale horseshoe type leading to a cascade of period doublings with increasing drive displacement amplitude culminating in chaos. The threshold value of the drive displacement amplitude at tangency is obtained in terms of the acoustic drive frequency and fluid attenuation coefficient. The model prediction of subharmonic generation leading to chaos is validated from acousto-optic diffraction measurements in a water-filled cavity using a 5 MHz acoustic drive frequency and from the measured frequency spectrum in the bifurcation cascade regime. The calculated resonant threshold amplitude of 0.2 nm for tangency is consistent with values estimated for the experimental set-up. Experimental evidence for the appearance of a stable subharmonic beyond chaos is reported.

Oscillating load-induced acoustic emission in laboratory experiment

USGS Publications Warehouse

Ponomarev, Alexander; Lockner, David A.; Stroganova, S.; Stanchits, S.; Smirnov, Vladmir

2010-01-01

Spatial and temporal patterns of acoustic emission (AE) were studied. A pre-fractured cylinder of granite was loaded in a triaxial machine at 160 MPa confining pressure until stick-slip events occurred. The experiments were conducted at a constant strain rate of 10−7 s−1 that was modulated by small-amplitude sinusoidal oscillations with periods of 175 and 570 seconds. Amplitude of the oscillations was a few percent of the total load and was intended to simulate periodic loading observed in nature (e.g., earth tides or other sources). An ultrasonic acquisition system with 13 piezosensors recorded acoustic emissions that were generated during deformation of the sample. We observed a correlation between AE response and sinusoidal loading. The effect was more pronounced for higher frequency of the modulating force. A time-space spectral analysis for a “point” process was used to investigate details of the periodic AE components. The main result of the study was the correlation of oscillations of acoustic activity synchronized with the applied oscillating load. The intensity of the correlated AE activity was most pronounced in the “aftershock” sequences that followed large-amplitude AE events. We suggest that this is due to the higher strain-sensitivity of the failure area when the sample is in a transient, unstable mode. We also found that the synchronization of AE activity with the oscillating external load nearly disappeared in the period immediately after the stick-slip events and gradually recovered with further loading.

Improving Accuracy in Detecting Acoustic Onsets

ERIC Educational Resources Information Center

Duyck, Wouter; Anseel, Frederik; Szmalec, Arnaud; Mestdagh, Pascal; Tavernier, Antoine; Hartsuiker, Robert J.

2008-01-01

In current cognitive psychology, naming latencies are commonly measured by electronic voice keys that detect when sound exceeds a certain amplitude threshold. However, recent research (e.g., K. Rastle & M. H. Davis, 2002) has shown that these devices are particularly inaccurate in precisely detecting acoustic onsets. In this article, the authors…

Acoustic emission monitoring of degradation of cross ply laminates.

PubMed

Aggelis, D G; Barkoula, N M; Matikas, T E; Paipetis, A S

2010-06-01

The scope of this study is to relate the acoustic activity of damage in composites to the failure mechanisms associated with these materials. Cross ply fiber reinforced composites were subjected to tensile loading with recording of their acoustic activity. Acoustic emission (AE) parameters were employed to monitor the transition of the damage mechanism from transverse cracking (mode I) to delamination (mode II). Wave propagation measurements in between loading steps revealed an increase in the relative amplitude of the propagated wave, which was attributed to the development of delamination that confined the wave to the top longitudinal plies of the composite.

Deep seafloor arrivals in long range ocean acoustic propagation.

PubMed

Stephen, Ralph A; Bolmer, S Thompson; Udovydchenkov, Ilya A; Worcester, Peter F; Dzieciuch, Matthew A; Andrew, Rex K; Mercer, James A; Colosi, John A; Howe, Bruce M

2013-10-01

Ocean bottom seismometer observations at 5000 m depth during the long-range ocean acoustic propagation experiment in the North Pacific in 2004 show robust, coherent, late arrivals that are not readily explained by ocean acoustic propagation models. These "deep seafloor" arrivals are the largest amplitude arrivals on the vertical particle velocity channel for ranges from 500 to 3200 km. The travel times for six (of 16 observed) deep seafloor arrivals correspond to the sea surface reflection of an out-of-plane diffraction from a seamount that protrudes to about 4100 m depth and is about 18 km from the receivers. This out-of-plane bottom-diffracted surface-reflected energy is observed on the deep vertical line array about 35 dB below the peak amplitude arrivals and was previously misinterpreted as in-plane bottom-reflected surface-reflected energy. The structure of these arrivals from 500 to 3200 km range is remarkably robust. The bottom-diffracted surface-reflected mechanism provides a means for acoustic signals and noise from distant sources to appear with significant strength on the deep seafloor.

Strong wave/mean-flow coupling in baroclinic acoustic streaming

NASA Astrophysics Data System (ADS)

Chini, Greg; Michel, Guillaume

2017-11-01

Recently, Chini et al. demonstrated the potential for large-amplitude acoustic streaming in compressible channel flows subjected to strong background cross-channel density variations. In contrast with classic Rayleigh streaming, standing acoustic waves of O (ɛ) amplitude acquire vorticity owing to baroclinic torques acting throughout the domain rather than via viscous torques acting in Stokes boundary layers. More significantly, these baroclinically-driven streaming flows have a magnitude that also is O (ɛ) , i.e. comparable to that of the sound waves. In the present study, the consequent potential for fully two-way coupling between the waves and streaming flows is investigated using a novel WKBJ analysis. The analysis confirms that the wave-driven streaming flows are sufficiently strong to modify the background density gradient, thereby modifying the leading-order acoustic wave structure. Simulations of the wave/mean-flow system enabled by the WKBJ analysis are performed to illustrate the nature of the two-way coupling, which contrasts sharply with classic Rayleigh streaming, for which the waves can first be determined and the streaming flows subsequently computed.

The effect of time-variant acoustical properties on orchestral instrument timbres

NASA Astrophysics Data System (ADS)

Hajda, John Michael

1999-06-01

The goal of this study was to investigate the timbre of orchestral instrument tones. Kendall (1986) showed that time-variant features are important to instrument categorization. But the relative salience of specific time-variant features to each other and to other acoustical parameters is not known. As part of a convergence strategy, a battery of experiments was conducted to assess the importance of global amplitude envelope, spectral frequencies, and spectral amplitudes. An omnibus identification experiment investigated the salience of global envelope partitions (attack, steady state, and decay). Valid partitioning models should identify important boundary conditions in the evolution of a signal; therefore, these models should be based on signal characteristics. With the use of such a model for sustained continuant tones, the steady-state segment was more salient than the attack. These findings contradicted previous research, which used questionable operational definitions for signal partitioning. For the next set of experiments, instrument tones were analyzed by phase vocoder, and stimuli were created by additive synthesis. Edits and combinations of edits controlled global amplitude envelope, spectral frequencies, and relative spectral amplitudes. Perceptual measurements were made with distance estimation, Verbal Attribute Magnitude Estimation, and similarity scaling. Results indicated that the primary acoustical attribute was the long-time-average spectral centroid. Spectral centroid is a measure of the center of energy distribution for spectral frequency components. Instruments with high values of spectral centroid (bowed strings) sound nasal while instruments with low spectral centroid (flute, clarinet) sound not nasal. The secondary acoustical attribute was spectral amplitude time variance. Predictably, time variance correlated highly with subject ratings of vibrato. The control of relative spectral amplitudes was more salient than the control of global

Effect of D-amphetamine on emotion-potentiated startle in healthy humans: implications for psychopathy and antisocial behaviour.

PubMed

Corr, Philip J; Kumari, Veena

2013-01-01

An emerging literature associates increased dopaminergic neurotransmission with altered brain response to aversive stimuli in humans. The direction of the effect of dopamine on aversive motivation, however, remains unclear, with some studies reporting increased and others decreased amygdala activation to aversive stimuli following the administration of dopamine agonists. Potentiation of the startle response by aversive foreground stimuli provides an objective and directional measure of emotional reactivity and is considered useful as an index of the emotional effects of different drugs. We investigated the effects of two doses of D-amphetamine (5 and 10 mg), compared to placebo, for the first time to our knowledge, using the affect-startle paradigm. The study employed a between-subjects, double-blind design, with three conditions: 0 mg (placebo), and 5 and 10 mg D-amphetamine (initially n = 20/group; final sample: n = 18, placebo; n = 18, 5 mg; n = 16, 10 mg). After drug/placebo administration, startle responses (eyeblinks) to intermittent noise probes were measured during viewing of pleasant, neutral and unpleasant images. Participants' general and specific impulsivity and fear-related personality traits were also assessed. The three groups were comparable on personality traits. Only the placebo group showed significant startle potentiation by unpleasant, relative to neutral, images; this effect was absent in both 5- and 10-mg D-amphetamine groups (i.e. the same effect of D-amphetamine observed at different doses in different people). Our findings demonstrate a reduced aversive emotional response under D-amphetamine and may help to account for the known link between the use of psychostimulant drugs and antisocial behaviour.

Triad Resonance in the Gravity-Acoustic Family

NASA Astrophysics Data System (ADS)

Kadri, U.

2015-12-01

Resonance interactions of waves play a prominent role in energy share among the different wave types involved. Such interactions may significantly contribute, among others, to the evolution of the ocean energy spectrum by exchanging energy between surface-gravity waves; surface and internal gravity waves; or even surface and compression-type waves, that can transfer energy from the upper ocean through the whole water column reaching down to the seafloor. A resonant triad occurs among a triplet of waves, usually involving interaction of nonlinear terms of second order perturbed equations. Until recently, it has been believed that in a homogeneous fluid a resonant triad is possible only when tension forces are included, or at the limit of a shallow water, and that when the compressibility of water is considered, no resonant triads can occur within the family of gravity-acoustic waves. However, more recently it has been proved that, under some circumstances, resonant triads comprising two opposing surface-gravity waves of similar periods (though not identical) and a much longer acoustic-gravity wave, of almost double the frequency, exist [Kadri and Stiassnie 2013, J. Fluid Mech.735 R6]. Here, I report on a new resonant triad involving a gravity wave and two acoustic waves of almost double the length. Interestingly, the two acoustic waves propagate in the same direction with similar wavelengths, that are almost double of that of the gravity wave. The evolution of the wave triad amplitudes is periodic and it is derived analytically, in terms of Jacobian elliptic functions and elliptic integrals. The physical importance of this type of triad interactions is the modulation of pertinent acoustic signals, leading to inaccurate signal perceptions. Enclosed figure: presents an example spatio-temporal evolution of the wave triad amplitudes. The gravity wave (top) remains almost unaltered, while the envelope slowly displaces to the left. However, the prescribed acoustic

Neural Systems Involved in Fear and Anxiety Measured with Fear-Potentiated Startle

ERIC Educational Resources Information Center

Davis, Michael

2006-01-01

A good deal is now known about the neural circuitry involved in how conditioned fear can augment a simple reflex (fear-potentiated startle). This involves visual or auditory as well as shock pathways that project via the thalamus and perirhinal or insular cortex to the basolateral amygdala (BLA). The BLA projects to the central (CeA) and medial…

Combustion response to acoustic perturbation in liquid rocket engines

NASA Astrophysics Data System (ADS)

Ghafourian, Akbar

An experimental study of the effect of acoustic perturbations on combustion behavior of a model liquid propellant rocket engine has been carried out. A pair of compression drivers were used to excite transverse and longitudinal acoustic fields at strengths of up to 156.6 dB and 159.5 dB respectively in the combustion chamber of the experimental rocket engine. Propellant simulants were injected into the combustion chamber through a single element shear coaxial injector. Water and air were used in cold flow studies and ethanol and oxygen-enriched air were used as fuel and oxidizer in reacting hot flow studies. In cold flow studies an imposed transverse acoustic field had a more pronounced effect on the spray pattern than a longitudinal acoustic fields. A transverse acoustic field widened the spray by as much as 33 percent and the plane of impingement of the spray with chamber walls moved up closer to the injection plane. The behavior was strongly influenced by the gas phase velocity but was less sensitive to changes in the liquid phase velocity. In reacting hot flow studies the effects of changes in equivalence ratio, excitation amplitude, excitation frequency, liquid and gas phase velocity and chamber pressure on the response of the injector to imposed high frequency transverse acoustic excitation were measured. Reducing the equivalence ratio from 7.4 to 3.8 increased the chamber pressure response to the imposed excitation at 3000 Hz. Increasing the excitation amplitude from 147 dB to 155.6 dB at 3000 Hz increased the chamber pressure response to the excitation. In the frequency range of 1240 Hz to 3220 Hz, an excitation frequency of 3000 Hz resulted in the largest response of the chamber pressure indicating the importance of fluid dynamic coupling. Increasing the liquid phase velocity from 9.2 m/sec to 22.7 m/sec, did not change the amplitude of the chamber pressure response to excitation. This implied the importance of local equivalence ratio and not the overall

Acoustic radiation force control: Pulsating spherical carriers.

PubMed

Rajabi, Majid; Mojahed, Alireza

2018-02-01

The interaction between harmonic plane progressive acoustic beams and a pulsating spherical radiator is studied. The acoustic radiation force function exerted on the spherical body is derived as a function of the incident wave pressure and the monopole vibration characteristics (i.e., amplitude and phase) of the body. Two distinct strategies are presented in order to alter the radiation force effects (i.e., pushing and pulling states) by changing its magnitude and direction. In the first strategy, an incident wave field with known amplitude and phase is considered. It is analytically shown that the zero- radiation force state (i.e., radiation force function cancellation) is achievable for specific pulsation characteristics belong to a frequency-dependent straight line equation in the plane of real-imaginary components (i.e., Nyquist Plane) of prescribed surface displacement. It is illustrated that these characteristic lines divide the mentioned displacement plane into two regions of positive (i.e., pushing) and negative (i.e., pulling) radiation forces. In the second strategy, the zero, negative and positive states of radiation force are obtained through adjusting the incident wave field characteristics (i.e., amplitude and phase) which insonifies the radiator with prescribed pulsation characteristics. It is proved that zero radiation force state occurs for incident wave pressure characteristics belong to specific frequency-dependent circles in Nyquist plane of incident wave pressure. These characteristic circles divide the Nyquist plane into two distinct regions corresponding to positive (out of circles) and negative (in the circles) values of radiation force function. It is analytically shown that the maximum amplitude of negative radiation force is exactly equal to the amplitude of the (positive) radiation force exerted upon the sphere in the passive state, by the same incident field. The developed concepts are much more deepened by considering the required

Acoustic levitation and manipulation for space applications

NASA Technical Reports Server (NTRS)

Wang, T. G.

1979-01-01

A wide spectrum of experiments to be performed in space in a microgravity environment require levitation and manipulation of liquid or molten samples. A novel acoustic method has been developed at JPL for controlling liquid samples without physical contacts. This method utilizes the static pressure generated by three orthogonal acoustic standing waves excited within an enclosure. Furthermore, this method will allow the sample to be rotated and/or oscillated by modifying the phase angles and/or the amplitude of the acoustic field. This technique has been proven both in our laboratory and in a microgravity environment provided by KC-135 flights. Samples placed within our chamber driven at (1,0,0), (0,1,0), and (0,0,1), modes were indeed levitated, rotated, and oscillated.

Chirp resonance spectroscopy of single lipid-coated microbubbles using an "acoustical camera".

PubMed

Renaud, G; Bosch, J G; van der Steen, A F W; de Jong, N

2012-12-01

An acoustical method was developed to study the resonance of single lipid-coated microbubbles. The response of 127 SonoVue microbubbles to a swept sine excitation between 0.5 and 5.5 MHz with a peak acoustic pressure amplitude of 70 kPa was measured by means of a 25 MHz probing wave. The relative amplitude modulation in the signal scattered in response to the probing wave is approximately equal to the radial strain induced by the swept sine excitation. An average damping coefficient of 0.33 and an average resonance frequency of 2.5 MHz were measured. Microbubbles experienced an average peak radial strain of 20%.

STS-70 Discovery launch startling the birds

NASA Technical Reports Server (NTRS)

1995-01-01

Startled birds scatter as the stillness of a summer morning is broken by a giant's roar. The Space Shuttle Discovery thundered into space from launch Pad 39-B at 9:41:55:078 a.m. EDT. STS-70 is the 70th Shuttle flight overall, the 21st for Discovery (OV- 103), and the fourth Shuttle flight in 1995. On board for the nearly eight-day mission are a crew of five: Commander Terence 'Tom' Hendricks; Pilot Kevin R. Kregel; and Mission Specialists Nancy Jane Currie, Donald A. Thomas and Mary Ellen Weber. The crew's primary objective is to deploy the Tracking and Data Relay Satellite-G (TDRS-G), which will join a constellation of other TDRS spacecraft already on orbit.

Acoustic energy transmission in cast iron pipelines

NASA Astrophysics Data System (ADS)

Kiziroglou, Michail E.; Boyle, David E.; Wright, Steven W.; Yeatman, Eric M.

2015-12-01

In this paper we propose acoustic power transfer as a method for the remote powering of pipeline sensor nodes. A theoretical framework of acoustic power propagation in the ceramic transducers and the metal structures is drawn, based on the Mason equivalent circuit. The effect of mounting on the electrical response of piezoelectric transducers is studied experimentally. Using two identical transducer structures, power transmission of 0.33 mW through a 1 m long, 118 mm diameter cast iron pipe, with 8 mm wall thickness is demonstrated, at 1 V received voltage amplitude. A near-linear relationship between input and output voltage is observed. These results show that it is possible to deliver significant power to sensor nodes through acoustic waves in solid structures. The proposed method may enable the implementation of acoustic - powered wireless sensor nodes for structural and operation monitoring of pipeline infrastructure.

Effects of anxiety sensitivity and expectations on the modulation of the startle eyeblink response during a caffeine challenge.

PubMed

Benke, Christoph; Blumenthal, Terry D; Modeß, Christiane; Hamm, Alfons O; Pané-Farré, Christiane A

2015-09-01

The way in which the tendency to fear somatic arousal sensations (anxiety sensitivity), in interaction with the created expectations regarding arousal induction, might affect defensive responding to a symptom provocation challenge is not yet understood. The present study investigated the effect of anxiety sensitivity on autonomic arousal, startle eyeblink responses, and reported arousal and alertness to expected vs. unexpected caffeine consumption. To create a match/mismatch of expected and experienced arousal, high and low anxiety sensitive participants received caffeine vs. no drug either mixed in coffee (expectation of arousal induction) or in bitter lemon soda (no expectation of arousal induction) on four separate occasions. Autonomic arousal (heart rate, skin conductance level), respiration (end-tidal CO2, minute ventilation), defensive reflex responses (startle eyeblink), and reported arousal and alertness were recorded prior to, immediately and 30 min after beverage ingestion. Caffeine increased ventilation, autonomic arousal, and startle response magnitudes. Both groups showed comparable levels of autonomic and respiratory responses. The startle eyeblink responses were decreased when caffeine-induced arousal occurred unexpectedly, e.g., after administering caffeine in bitter lemon. This effect was more accentuated in high anxiety sensitive persons. Moreover, in high anxiety sensitive persons, the expectation of arousal (coffee consumption) led to higher subjective alertness when administering caffeine and increased arousal even if no drug was consumed. Unexpected symptom provocation leads to increased attention allocation toward feared arousal sensations in high anxiety sensitive persons. This finding broadens our understanding of modulatory mechanisms in defensive responding to bodily symptoms.

Cylindrical ion-acoustic solitary waves in electronegative plasmas with superthermal electrons

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eslami, Parvin; Mottaghizadeh, Marzieh

2012-06-15

By using the standard reductive perturbation technique, a three-dimensional cylindrical Kadomtsev-Petviashvili equation (CKPE), which governs the dynamics of ion acoustic solitary waves (IASWs), is derived for small but finite amplitude ion-acoustic waves in cylindrical geometry in a collisionless unmagnetized plasma with kappa distributed electrons, thermal positrons, and cold ions. The generalized expansion method is used to solve analytically the CKPE. The existence regions of localized pulses are investigated. It is found that the solution of the CKPE supports only compressive solitary waves. Furthermore, the effects of superthermal electrons, the ratio of the electron temperature to positron temperature, the ratio ofmore » the positron density to electron density and direction cosine of the wave propagation on the profiles of the amplitudes, and widths of the solitary structures are examined numerically. It is shown these parameters play a vital role in the formation of ion acoustic solitary waves.« less

NOTE ON TRAVEL TIME SHIFTS DUE TO AMPLITUDE MODULATION IN TIME-DISTANCE HELIOSEISMOLOGY MEASUREMENTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nigam, R.; Kosovichev, A. G., E-mail: rakesh@quake.stanford.ed, E-mail: sasha@quake.stanford.ed

Correct interpretation of acoustic travel times measured by time-distance helioseismology is essential to get an accurate understanding of the solar properties that are inferred from them. It has long been observed that sunspots suppress p-mode amplitude, but its implications on travel times have not been fully investigated so far. It has been found in test measurements using a 'masking' procedure, in which the solar Doppler signal in a localized quiet region of the Sun is artificially suppressed by a spatial function, and using numerical simulations that the amplitude modulations in combination with the phase-speed filtering may cause systematic shifts ofmore » acoustic travel times. To understand the properties of this procedure, we derive an analytical expression for the cross-covariance of a signal that has been modulated locally by a spatial function that has azimuthal symmetry and then filtered by a phase-speed filter typically used in time-distance helioseismology. Comparing this expression to the Gabor wavelet fitting formula without this effect, we find that there is a shift in the travel times that is introduced by the amplitude modulation. The analytical model presented in this paper can be useful also for interpretation of travel time measurements for the non-uniform distribution of oscillation amplitude due to observational effects.« less

Measurement of acoustic attenuation in South Pole ice

NASA Astrophysics Data System (ADS)

IceCube Collaboration; Abbasi, R.; Abdou, Y.; Abu-Zayyad, T.; Adams, J.; Aguilar, J. A.; Ahlers, M.; Andeen, K.; Auffenberg, J.; Bai, X.; Baker, M.; Barwick, S. W.; Bay, R.; Bazo Alba, J. L.; Beattie, K.; Beatty, J. J.; Bechet, S.; Becker, J. K.; Becker, K.-H.; Benabderrahmane, M. L.; Berdermann, J.; Berghaus, P.; Berley, D.; Bernardini, E.; Bertrand, D.; Besson, D. Z.; Bissok, M.; Blaufuss, E.; Boersma, D. J.; Bohm, C.; Böser, S.; Botner, O.; Bradley, L.; Braun, J.; Buitink, S.; Carson, M.; Chirkin, D.; Christy, B.; Clem, J.; Clevermann, F.; Cohen, S.; Colnard, C.; Cowen, D. F.; D'Agostino, M. V.; Danninger, M.; de Clercq, C.; Demirörs, L.; Depaepe, O.; Descamps, F.; Desiati, P.; de Vries-Uiterweerd, G.; Deyoung, T.; Díaz-Vélez, J. C.; Dreyer, J.; Dumm, J. P.; Duvoort, M. R.; Ehrlich, R.; Eisch, J.; Ellsworth, R. W.; Engdegård, O.; Euler, S.; Evenson, P. A.; Fadiran, O.; Fazely, A. R.; Feusels, T.; Filimonov, K.; Finley, C.; Foerster, M. M.; Fox, B. D.; Franckowiak, A.; Franke, R.; Gaisser, T. K.; Gallagher, J.; Ganugapati, R.; Geisler, M.; Gerhardt, L.; Gladstone, L.; Glüsenkamp, T.; Goldschmidt, A.; Goodman, J. A.; Grant, D.; Griesel, T.; Groß, A.; Grullon, S.; Gunasingha, R. M.; Gurtner, M.; Gustafsson, L.; Ha, C.; Hallgren, A.; Halzen, F.; Han, K.; Hanson, K.; Helbing, K.; Herquet, P.; Hickford, S.; Hill, G. C.; Hoffman, K. D.; Homeier, A.; Hoshina, K.; Hubert, D.; Huelsnitz, W.; Hülß, J.-P.; Hulth, P. O.; Hultqvist, K.; Hussain, S.; Imlay, R. L.; Ishihara, A.; Jacobsen, J.; Japaridze, G. S.; Johansson, H.; Joseph, J. M.; Kampert, K.-H.; Kappes, A.; Karg, T.; Karle, A.; Kelley, J. L.; Kemming, N.; Kenny, P.; Kiryluk, J.; Kislat, F.; Klein, S. R.; Knops, S.; Köhne, J.-H.; Kohnen, G.; Kolanoski, H.; Köpke, L.; Koskinen, D. J.; Kowalski, M.; Kowarik, T.; Krasberg, M.; Krings, T.; Kroll, G.; Kuehn, K.; Kuwabara, T.; Labare, M.; Lafebre, S.; Laihem, K.; Landsman, H.; Lauer, R.; Lehmann, R.; Lennarz, D.; Lünemann, J.; Madsen, J.; Majumdar, P.; Maruyama, R.; Mase, K.; Matis, H. S.; Matusik, M.; Meagher, K.; Merck, M.; Mészáros, P.; Meures, T.; Middell, E.; Milke, N.; Montaruli, T.; Morse, R.; Movit, S. M.; Nahnhauer, R.; Nam, J. W.; Naumann, U.; Nießen, P.; Nygren, D. R.; Odrowski, S.; Olivas, A.; Olivo, M.; Ono, M.; Panknin, S.; Paul, L.; Pérez de Los Heros, C.; Petrovic, J.; Piegsa, A.; Pieloth, D.; Porrata, R.; Posselt, J.; Price, P. B.; Prikockis, M.; Przybylski, G. T.; Rawlins, K.; Redl, P.; Resconi, E.; Rhode, W.; Ribordy, M.; Rizzo, A.; Rodrigues, J. P.; Roth, P.; Rothmaier, F.; Rott, C.; Roucelle, C.; Ruhe, T.; Rutledge, D.; Ruzybayev, B.; Ryckbosch, D.; Sander, H.-G.; Sarkar, S.; Schatto, K.; Schlenstedt, S.; Schmidt, T.; Schneider, D.; Schukraft, A.; Schultes, A.; Schulz, O.; Schunck, M.; Seckel, D.; Semburg, B.; Seo, S. H.; Sestayo, Y.; Seunarine, S.; Silvestri, A.; Slipak, A.; Spiczak, G. M.; Spiering, C.; Stamatikos, M.; Stanev, T.; Stephens, G.; Stezelberger, T.; Stokstad, R. G.; Stoyanov, S.; Strahler, E. A.; Straszheim, T.; Sullivan, G. W.; Swillens, Q.; Taboada, I.; Tamburro, A.; Tarasova, O.; Tepe, A.; Ter-Antonyan, S.; Tilav, S.; Toale, P. A.; Tosi, D.; Turčan, D.; van Eijndhoven, N.; Vandenbroucke, J.; van Overloop, A.; van Santen, J.; Voigt, B.; Walck, C.; Waldenmaier, T.; Wallraff, M.; Walter, M.; Wendt, C.; Westerhoff, S.; Whitehorn, N.; Wiebe, K.; Wiebusch, C. H.; Wikström, G.; Williams, D. R.; Wischnewski, R.; Wissing, H.; Woschnagg, K.; Xu, C.; Xu, X. W.; Yanez, J. P.; Yodh, G.; Yoshida, S.; Zarzhitsky, P.; IceCube Collaboration

2011-01-01

Using the South Pole Acoustic Test Setup (SPATS) and a retrievable transmitter deployed in holes drilled for the IceCube experiment, we have measured the attenuation of acoustic signals by South Pole ice at depths between 190 m and 500 m. Three data sets, using different acoustic sources, have been analyzed and give consistent results. The method with the smallest systematic uncertainties yields an amplitude attenuation coefficient α = 3.20 ± 0.57 km-1 between 10 and 30 kHz, considerably larger than previous theoretical estimates. Expressed as an attenuation length, the analyses give a consistent result for λ ≡ 1/α of ˜300 m with 20% uncertainty. No significant depth or frequency dependence has been found.

Laser and acoustic lens for lithotripsy

DOEpatents

Visuri, Steven R.; Makarewicz, Anthony J.; London, Richard A.; Benett, William J.; Krulevitch, Peter; Da Silva, Luiz B.

2002-01-01

An acoustic focusing device whose acoustic waves are generated by laser radiation through an optical fiber. The acoustic energy is capable of efficient destruction of renal and biliary calculi and deliverable to the site of the calculi via an endoscopic procedure. The device includes a transducer tip attached to the distal end of an optical fiber through which laser energy is directed. The transducer tip encapsulates an exogenous absorbing dye. Under proper irradiation conditions (high absorbed energy density, short pulse duration) a stress wave is produced via thermoelastic expansion of the absorber for the destruction of the calculi. The transducer tip can be configured into an acoustic lens such that the transmitted acoustic wave is shaped or focused. Also, compressive stress waves can be reflected off a high density/low density interface to invert the compressive wave into a tensile stress wave, and tensile stresses may be more effective in some instances in disrupting material as most materials are weaker in tension than compression. Estimations indicate that stress amplitudes provided by this device can be magnified more than 100 times, greatly improving the efficiency of optical energy for targeted material destruction.

Motion measurement of acoustically levitated object

NASA Technical Reports Server (NTRS)

Watkins, John L. (Inventor); Barmatz, Martin B. (Inventor)

1993-01-01

A system is described for determining motion of an object that is acoustically positioned in a standing wave field in a chamber. Sonic energy in the chamber is sensed, and variation in the amplitude of the sonic energy is detected, which is caused by linear motion, rotational motion, or drop shape oscillation of the object. Apparatus for detecting object motion can include a microphone coupled to the chamber and a low pass filter connected to the output of the microphone, which passes only frequencies below the frequency of sound produced by a transducer that maintains the acoustic standing wave field. Knowledge about object motion can be useful by itself, can be useful to determine surface tension, viscosity, and other information about the object, and can be useful to determine the pressure and other characteristics of the acoustic field.

A steadying effect of acoustic excitation on transitory stall

NASA Technical Reports Server (NTRS)

Zaman, K. B. M. Q.

1991-01-01

The effect of acoustic excitation on a class of separated flows with a transitional boundary layer at the point of separation is considered. Experimental results on the flow over airfoils, a two-dimensional backward-facing step, and through large angle conical diffusers are presented. In all cases, the separated flow undergoes large amplitude fluctuations, much of the energy being concentrated at unusually low frequencies. In each case, an appropriate high frequency acoustic excitation is found to be effective in reducing the fluctuations substantially. The effective excitation frequency scales on the initial boundary layer thickness and the effect is apparently achieved through acoustic tripping of the separating boundary layer.

CRF receptor blockade prevents initiation and consolidation of stress effects on affect in the predator stress model of PTSD.

PubMed

Adamec, Robert; Fougere, Dennis; Risbrough, Victoria

2010-07-01

Post traumatic stress disorder (PTSD) is a chronic anxiety disorder initiated by an intensely threatening, traumatic event. There is a great need for more efficacious pharmacotherapy and preventive treatments for PTSD. In animals, corticotropin-releasing factor (CRF) and the CRF1 receptor play a critical role in behavioural and neuroendocrine responses to stress. We tested the hypothesis that CRF1 activation is required for initiation and consolidation of long-term effects of trauma on anxiety-like behaviour in the predator exposure (predator stress) model of PTSD. Male C57BL6 mice were treated with the selective CRF1 antagonist CRA0450 (2, 20 mg/kg) 30 min before or just after predator stress. Long-term effects of stress on rodent anxiety were measured 7 d later using acoustic startle, elevated plus maze (EPM), light/dark box, and hole-board tests. Predator stress increased startle amplitude and delayed startle habituation, increased time in and decreased exits from the dark chamber in the light/dark box test, and decreased risk assessment in the EPM. CRF1 antagonism had limited effects on these behaviours in non-stressed controls, with the high dose decreasing risk assessment in the EPM. However, in stressed animals CRF1 antagonism blocked initiation and consolidation of stressor effects on startle, and returned risk assessment to baseline levels in predator-stressed mice. These findings implicate CRF1 activation in initiation and post-trauma consolidation of predator stress effects on anxiety-like behaviour, specifically on increased arousal as measured by exaggerated startle behaviours. These data support further research of CRF1 antagonists as potential prophylactic treatments for PTSD.

PREDICTIVE MODELING OF ACOUSTIC SIGNALS FROM THERMOACOUSTIC POWER SENSORS (TAPS)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dumm, Christopher M.; Vipperman, Jeffrey S.

2016-06-30

Thermoacoustic Power Sensor (TAPS) technology offers the potential for self-powered, wireless measurement of nuclear reactor core operating conditions. TAPS are based on thermoacoustic engines, which harness thermal energy from fission reactions to generate acoustic waves by virtue of gas motion through a porous stack of thermally nonconductive material. TAPS can be placed in the core, where they generate acoustic waves whose frequency and amplitude are proportional to the local temperature and radiation flux, respectively. TAPS acoustic signals are not measured directly at the TAPS; rather, they propagate wirelessly from an individual TAPS through the reactor, and ultimately to a low-powermore » receiver network on the vessel’s exterior. In order to rely on TAPS as primary instrumentation, reactor-specific models which account for geometric/acoustic complexities in the signal propagation environment must be used to predict the amplitude and frequency of TAPS signals at receiver locations. The reactor state may then be derived by comparing receiver signals to the reference levels established by predictive modeling. In this paper, we develop and experimentally benchmark a methodology for predictive modeling of the signals generated by a TAPS system, with the intent of subsequently extending these efforts to modeling of TAPS in a liquid sodium environmen« less

Locating interfaces in vertically-layered materials and determining concentrations in mixed materials utilizing acoustic impedance measurements

DOEpatents

Langlois, Gary N.

1983-09-13

Measurement of the relative and actual value of acoustic characteristic impedances of an unknown substance, location of the interfaces of vertically-layered materials, and the determination of the concentration of a first material mixed in a second material. A highly damped ultrasonic pulse is transmitted into one side of a reference plate, such as a tank wall, where the other side of the reference plate is in physical contact with the medium to be measured. The amplitude of a return signal, which is the reflection of the transmitted pulse from the interface between the other side of the reference plate and the medium, is measured. The amplitude value indicates the acoustic characteristic impedance of the substance relative to that of the reference plate or relative to that of other tested materials. Discontinuities in amplitude with repeated measurements for various heights indicate the location of interfaces in vertically-layered materials. Standardization techniques permit the relative acoustic characteristic impedance of a substance to be converted to an actual value. Calibration techniques for mixtures permit the amplitude to be converted to the concentration of a first material mixed in a second material.

Locating interfaces in vertically-layered materials and determining concentrations in mixed materials utilizing acoustic impedance measurements

DOEpatents

Langlois, G.N.

1983-09-13

Measurement of the relative and actual value of acoustic characteristic impedances of an unknown substance, location of the interfaces of vertically-layered materials, and the determination of the concentration of a first material mixed in a second material are disclosed. A highly damped ultrasonic pulse is transmitted into one side of a reference plate, such as a tank wall, where the other side of the reference plate is in physical contact with the medium to be measured. The amplitude of a return signal, which is the reflection of the transmitted pulse from the interface between the other side of the reference plate and the medium, is measured. The amplitude value indicates the acoustic characteristic impedance of the substance relative to that of the reference plate or relative to that of other tested materials. Discontinuities in amplitude with repeated measurements for various heights indicate the location of interfaces in vertically-layered materials. Standardization techniques permit the relative acoustic characteristic impedance of a substance to be converted to an actual value. Calibration techniques for mixtures permit the amplitude to be converted to the concentration of a first material mixed in a second material. 6 figs.

Increasing power-law range in avalanche amplitude and energy distributions

NASA Astrophysics Data System (ADS)

Navas-Portella, Víctor; Serra, Isabel; Corral, Álvaro; Vives, Eduard

2018-02-01

Power-law-type probability density functions spanning several orders of magnitude are found for different avalanche properties. We propose a methodology to overcome empirical constraints that limit the range of truncated power-law distributions. By considering catalogs of events that cover different observation windows, the maximum likelihood estimation of a global power-law exponent is computed. This methodology is applied to amplitude and energy distributions of acoustic emission avalanches in failure-under-compression experiments of a nanoporous silica glass, finding in some cases global exponents in an unprecedented broad range: 4.5 decades for amplitudes and 9.5 decades for energies. In the latter case, however, strict statistical analysis suggests experimental limitations might alter the power-law behavior.

Increasing power-law range in avalanche amplitude and energy distributions.

PubMed

Navas-Portella, Víctor; Serra, Isabel; Corral, Álvaro; Vives, Eduard

2018-02-01

Power-law-type probability density functions spanning several orders of magnitude are found for different avalanche properties. We propose a methodology to overcome empirical constraints that limit the range of truncated power-law distributions. By considering catalogs of events that cover different observation windows, the maximum likelihood estimation of a global power-law exponent is computed. This methodology is applied to amplitude and energy distributions of acoustic emission avalanches in failure-under-compression experiments of a nanoporous silica glass, finding in some cases global exponents in an unprecedented broad range: 4.5 decades for amplitudes and 9.5 decades for energies. In the latter case, however, strict statistical analysis suggests experimental limitations might alter the power-law behavior.

Finite amplitude effects on drop levitation for material properties measurement

NASA Astrophysics Data System (ADS)

Ansari Hosseinzadeh, Vahideh; Holt, R. Glynn

2017-05-01

The method of exciting shape oscillation of drops to extract material properties has a long history, which is most often coupled with the technique of acoustic levitation to achieve non-contact manipulation of the drop sample. We revisit this method with application to the inference of bulk shear viscosity and surface tension. The literature is replete with references to a "10% oscillation amplitude" as a sufficient condition for the application of Lamb's analytical expressions for the shape oscillations of viscous liquids. Our results show that even a 10% oscillation amplitude leads to dynamic effects which render Lamb's results inapplicable. By comparison with samples of known viscosity and surface tension, we illustrate the complicating finite-amplitude effects (mode-splitting and excess dissipation associated with vorticity) that can occur and then show that sufficiently small oscillations allow us to recover the correct material properties using Lamb's formula.

Evidence of Fearlessness in Behaviourally Disordered Children: A Study on Startle Reflex Modulation

ERIC Educational Resources Information Center

van Goozen, Stephanie H. M.; Snoek, Heddeke; Matthys, Walter; van Rossum, Inge; van Engeland, Herman

2004-01-01

Background: Patterns of low heart rate, skin conductance and cortisol seem to characterise children with disruptive behaviour disorder (DBD). Until now, the startle paradigm has not been used in DBD children. We investigated whether DBD children, like adult psychopaths, process emotional stimuli in an abnormal way. Method: Twenty-one DBD and 33…

Reflection and Refraction of Acoustic Waves by a Shock Wave

NASA Technical Reports Server (NTRS)

Brillouin, J.

1957-01-01

The presence of sound waves in one or the other of the fluid regions on either side of a shock wave is made apparent, in the region under superpressure, by acoustic waves (reflected or refracted according to whether the incident waves lie in the region of superpressure or of subpressure) and by thermal waves. The characteristics of these waves are calculated for a plane, progressive, and uniform incident wave. In the case of refraction, the refracted acoustic wave can, according to the incidence, be plane, progressive, and uniform or take the form of an 'accompanying wave' which remains attached to the front of the shock while sliding parallel to it. In all cases, geometrical constructions permit determination of the kinematic characteristics of the reflected or refractive acoustic waves. The dynamic relationships show that the amplitude of the reflected wave is always less than that of the incident wave. The amplitude of the refracted wave, whatever its type, may in certain cases be greater than that of the incident wave.

Effect of ion temperature on ion-acoustic solitary waves in a magnetized plasma in presence of superthermal electrons

DOE Office of Scientific and Technical Information (OSTI.GOV)

Singh, S. V.; Devanandhan, S.; Lakhina, G. S.

2013-01-15

Obliquely propagating ion-acoustic soliatry waves are examined in a magnetized plasma composed of kappa distributed electrons and fluid ions with finite temperature. The Sagdeev potential approach is used to study the properties of finite amplitude solitary waves. Using a quasi-neutrality condition, it is possible to reduce the set of equations to a single equation (energy integral equation), which describes the evolution of ion-acoustic solitary waves in magnetized plasmas. The temperature of warm ions affects the speed, amplitude, width, and pulse duration of solitons. Both the critical and the upper Mach numbers are increased by an increase in the ion temperature.more » The ion-acoustic soliton amplitude increases with the increase in superthermality of electrons. For auroral plasma parameters, the model predicts the soliton speed, amplitude, width, and pulse duration, respectively, to be in the range of (28.7-31.8) km/s, (0.18-20.1) mV/m; (590-167) m, and (20.5-5.25) ms, which are in good agreement with Viking observations.« less

Acoustic emission from trabecular bone during mechanical testing: the effect of osteoporosis and osteoarthritis.

PubMed

Leichter, I; Bivas, A; Margulies, J Y; Roman, I; Simkin, A

1990-01-01

This study examines the relation between the nature of acoustic emission signals emitted from cancellous bone under compression and the mechanical properties of the tissue. The examined bone specimens were taken from 12 normal, 31 osteoporotic and six osteoarthritic femoral heads. The mechanical behaviour of the osteoporotic bone specimens was found to be significantly different from that of the normal specimens both in the pre-yield and post-yield ranges. In the osteoarthritic bones only the elastic behaviour was significantly different. The rates of acoustic events before yield and beyond it were found to be significantly higher both in the osteoporotic and osteoarthritic bone specimens. The average peak amplitude of the signals was also significantly higher in the diseased bones. Stepwise regression analysis showed that a combination of the acoustic emission parameters could significantly predict some mechanical properties of the bone. The energy absorbed during compression and the ultimate compressive stress of the specimens could be estimated from the rate of pre-yield acoustic events, the average amplitude of the signals and the rate of post-yield events. However, the explanation power of the acoustic emission parameters was only moderate. The nature of acoustic emission signals was thus demonstrated to be a potential tool for assessing bone quality.

Sources and Radiation Patterns of Volcano-Acoustic Signals Investigated with Field-Scale Chemical Explosions

NASA Astrophysics Data System (ADS)

Bowman, D. C.; Lees, J. M.; Taddeucci, J.; Graettinger, A. H.; Sonder, I.; Valentine, G.

2014-12-01

We investigate the processes that give rise to complex acoustic signals during volcanic blasts by monitoring buried chemical explosions with infrasound and audio range microphones, strong motion sensors, and high speed imagery. Acoustic waveforms vary with scaled depth of burial (SDOB, units in meters per cube root of joules), ranging from high amplitude, impulsive, gas expansion dominated signals at low SDOB to low amplitude, longer duration, ground motion dominated signals at high SDOB. Typically, the sudden upward acceleration of the substrate above the blast produces the first acoustic arrival, followed by a second pulse due to the eruption of pressurized gas at the surface. Occasionally, a third overpressure occurs when displaced material decelerates upon impact with the ground. The transition between ground motion dominated and gas release dominated acoustics ranges between 0.0038-0.0018 SDOB, respectively. For example, one explosion registering an SDOB=0.0031 produced two overpressure pulses of approximately equal amplitude, one due to ground motion, the other to gas release. Recorded volcano infrasound has also identified distinct ground motion and gas release components during explosions at Sakurajima, Santiaguito, and Karymsky volcanoes. Our results indicate that infrasound records may provide a proxy for the depth and energy of these explosions. Furthermore, while magma fragmentation models indicate the possibility of several explosions during a single vulcanian eruption (Alidibirov, Bull Volc., 1994), our results suggest that a single explosion can also produce complex acoustic signals. Thus acoustic records alone cannot be used to distinguish between single explosions and multiple closely-spaced blasts at volcanoes. Results from a series of lateral blasts during the 2014 field experiment further indicates whether vent geometry can produce directional acoustic radiation patterns like those observed at Tungarahua volcano (Kim et al., GJI, 2012). Beside

Iron Deficiency with or without Anemia Impairs Prepulse Inhibition of the Startle Reflex

PubMed Central

Pisansky, Marc T.; Wickham, Robert J.; Su, Jianjun; Fretham, Stephanie; Yuan, Li-Lian; Sun, Mu; Gewirtz, Jonathan C.; Georgieff, Michael K.

2013-01-01

Iron deficiency (ID) during early life causes long-lasting detrimental cognitive sequelae, many of which are linked to alterations in hippocampus function, dopamine synthesis, and the modulation of dopaminergic circuitry by the hippocampus. These same features have been implicated in the origins of schizophrenia, a neuropsychiatric disorder with significant cognitive impairments. Deficits in sensorimotor gating represent a reliable endophenotype of schizophrenia that can be measured by prepulse inhibition (PPI) of the acoustic startle reflex. Using two rodent model systems, we investigated the influence of early-life ID on PPI in adulthood. To isolate the role of hippocampal iron in PPI, our mouse model utilized a timed (embryonic day 18.5), hippocampus-specific knockout of Slc11a2, a gene coding an important regulator of cellular iron uptake, the divalent metal transport type 1 protein (DMT-1). Our second model used a classic rat dietary-based global ID during gestation, a condition that closely mimics human gestational ID anemia (IDA). Both models exhibited impaired PPI in adulthood. Furthermore, our DMT-1 knockout model displayed reduced long-term potentiation (LTP) and elevated paired pulse facilitation (PPF), electrophysiological results consistent with previous findings in the IDA rat model. These results, in combination with previous findings demonstrating impaired hippocampus functioning and altered dopaminergic and glutamatergic neurotransmission, suggest that iron availability within the hippocampus is critical for the neurodevelopmental processes underlying sensorimotor gating. Ultimately, evidence of reduced PPI in both of our models may offer insights into the roles of fetal ID and the hippocampus in the pathophysiology of schizophrenia. PMID:23733517

Behavioral and electrophysiological auditory processing measures in traumatic brain injury after acoustically controlled auditory training: a long-term study

PubMed Central

Figueiredo, Carolina Calsolari; de Andrade, Adriana Neves; Marangoni-Castan, Andréa Tortosa; Gil, Daniela; Suriano, Italo Capraro

2015-01-01

ABSTRACT Objective To investigate the long-term efficacy of acoustically controlled auditory training in adults after tarumatic brain injury. Methods A total of six audioogically normal individuals aged between 20 and 37 years were studied. They suffered severe traumatic brain injury with diffuse axional lesion and underwent an acoustically controlled auditory training program approximately one year before. The results obtained in the behavioral and electrophysiological evaluation of auditory processing immediately after acoustically controlled auditory training were compared to reassessment findings, one year later. Results Quantitative analysis of auditory brainsteim response showed increased absolute latency of all waves and interpeak intervals, bilaterraly, when comparing both evaluations. Moreover, increased amplitude of all waves, and the wave V amplitude was statistically significant for the right ear, and wave III for the left ear. As to P3, decreased latency and increased amplitude were found for both ears in reassessment. The previous and current behavioral assessment showed similar results, except for the staggered spondaic words in the left ear and the amount of errors on the dichotic consonant-vowel test. Conclusion The acoustically controlled auditory training was effective in the long run, since better latency and amplitude results were observed in the electrophysiological evaluation, in addition to stability of behavioral measures after one-year training. PMID:26676270

Noninvasive treatment alternative for intractable startle epilepsy

PubMed Central

Klinkenberg, Sylvia; Ubbink, Sander; Vles, Johannes; de Louw, Anton; van Hall, Mariette Debeij; Scheijen, Dyon; Brokx, Jan

2014-01-01

We describe a treatment alternative for intractable, startle-provoked, epileptic seizures in four children aged between 8 and 14. Three of the four children had symptomatic localization-related epilepsy. They all suffered from intractable epilepsy precipitated by sudden sounds. The fact that seizures tended to occur with high frequency – more than one seizure a day – had a clear impact on daily life. Clinical seizure pattern demonstrated asymmetric tonic posturing in all four children. Three children experienced several seizure types including focal seizure onset. All children had focal neurological signs or learning disabilities or a combination of both. Our noninvasive treatment method using psychoeducational counseling and sound generators was applied in four children, resulting in a seizure frequency reduction of ≥ 50% in two of them. PMID:25667869

Effects of background noise on acoustic characteristics of Bengalese finch songs.

PubMed

Shiba, Shintaro; Okanoya, Kazuo; Tachibana, Ryosuke O

2016-12-01

Online regulation of vocalization in response to auditory feedback is one of the essential issues for vocal communication. One such audio-vocal interaction is the Lombard effect, an involuntary increase in vocal amplitude in response to the presence of background noise. Along with vocal amplitude, other acoustic characteristics, including fundamental frequency (F0), also change in some species. Bengalese finches (Lonchura striata var. domestica) are a suitable model for comparative, ethological, and neuroscientific studies on audio-vocal interaction because they require real-time auditory feedback of their own songs to maintain normal singing. Here, the changes in amplitude and F0 with a focus on the distinct song elements (i.e., notes) of Bengalese finches under noise presentation are demonstrated. To accurately analyze these acoustic characteristics, two different bandpass-filtered noises at two levels of sound intensity were used. The results confirmed that the Lombard effect occurs at the note level of Bengalese finch song. Further, individually specific modes of changes in F0 are shown. These behavioral changes suggested the vocal control mechanisms on which the auditory feedback is based have a predictable effect on amplitude, but complex spectral effects on individual note production.

Finding intonational boundaries using acoustic cues related to the voice source

NASA Astrophysics Data System (ADS)

Choi, Jeung-Yoon; Hasegawa-Johnson, Mark; Cole, Jennifer

2005-10-01

Acoustic cues related to the voice source, including harmonic structure and spectral tilt, were examined for relevance to prosodic boundary detection. The measurements considered here comprise five categories: duration, pitch, harmonic structure, spectral tilt, and amplitude. Distributions of the measurements and statistical analysis show that the measurements may be used to differentiate between prosodic categories. Detection experiments on the Boston University Radio Speech Corpus show equal error detection rates around 70% for accent and boundary detection, using only the acoustic measurements described, without any lexical or syntactic information. Further investigation of the detection results shows that duration and amplitude measurements, and, to a lesser degree, pitch measurements, are useful for detecting accents, while all voice source measurements except pitch measurements are useful for boundary detection.

Nonlinear response and bistability of driven ion acoustic waves

NASA Astrophysics Data System (ADS)

Akbari-Moghanjoughi, M.

2017-08-01

The hydrodynamic model is used to obtain a generalized pseudoforce equation through which the nonlinear response of periodically driven ion acoustic waves is studied in an electron-ion plasma with isothermal and adiabatic ion fluids. The pseudotime series, corresponding to different driving frequencies, indicates that nonlinearity effects appear more strongly for smaller frequency values. The existence of extra harmonic resonances in the nonlinear amplitude spectrum is a clear indication of the interaction of an external force with harmonic components of the nonlinear ion acoustic waves. It is shown that many plasma parameters significantly and differently affect the nonlinear resonance spectrum of ion acoustic excitations. A heuristic but accurate model for the foldover effect is used which quite satisfactorily predicts the bistability of driven plasma oscillations. It is remarked that the characteristic resonance peak of isothermal ion plasma oscillations appears at lower frequencies but is stronger compared to that of adiabatic ions. Comparison of the exact numerical results for fully nonlinear and approximate (weakly nonlinear) models indicates that a weakly nonlinear model exaggerates the hysteresis and jump phenomenon for higher values of the external force amplitude.

Increased startle potentiation to unpredictable stressors in alcohol dependence: Possible stress neuroadaptation in humans

PubMed Central

Moberg, Christine A.; Bradford, Daniel E.; Kaye, Jesse T.; Curtin, John J.

2017-01-01

Stress plays a key role in addiction etiology and relapse. Rodent models posit that following repeated periods of alcohol and other drug intoxication, compensatory allostatic changes occur in the central nervous system (CNS) circuits involved in behavioral and emotional response to stressors. We examine a predicted manifestation of this neuroadaptation in recently abstinent alcohol dependent humans. Participants completed a translational laboratory task that uses startle potentiation to unpredictable (vs. predictable) stressors implicated in the putative CNS mechanisms that mediate this neuroadaptation. Alcohol dependent participants displayed significantly greater startle potentiation to unpredictable than predictable stressors relative to non-alcoholic controls. The size of this effect covaried with alcohol-related problems and degree of withdrawal syndrome. This supports the rodent model thesis of a sensitized stress response in abstinent alcoholics. However, this effect could also represent pre-morbid risk or mark more severe and/or comorbid psychopathology. Regardless, pharmacotherapy and psychological interventions may target unpredictable stressor response to reduce stress-induced relapse. PMID:28394145

The effect of choice on the physiology of emotion: An affective startle modulation study

PubMed Central

Genevsky, Alexander; Gard, David E.

2014-01-01

The affective startle modulation task has been an important measure in understanding physiological aspects of emotion and motivational responses. Research utilizing this method has relied primarily on a ‘passive’ viewing paradigm, which stands in contrast to everyday life where much of emotion and motivation involves some active choice or agency. The present study investigated the role of choice on the physiology of emotion. Eighty-four participants were randomized into ‘choice’ (n=44) or ‘no-choice’ (n=40) groups distinguished by the ability to choose between stimuli. EMG eye blink responses were recorded in both anticipation and stimulus viewing. Results indicated a significant attenuation of the startle magnitude in choice condition trials (relative to no-choice) across all picture categories and probe times. We interpret these findings as an indication that the act of choice may decrease one’s defensive response, or conversely, lacking choice may heighten the defensive response. Implications for future research are discussed. PMID:22285891

The effect of choice on the physiology of emotion: an affective startle modulation study.

PubMed

Genevsky, Alexander; Gard, David E

2012-04-01

The affective startle modulation task has been an important measure in understanding physiological aspects of emotion and motivational responses. Research utilizing this method has relied primarily on a 'passive' viewing paradigm, which stands in contrast to everyday life where much of emotion and motivation involves some active choice or agency. The present study investigated the role of choice on the physiology of emotion. Eighty-four participants were randomized into 'choice' (n=44) or 'no-choice' (n=40) groups distinguished by the ability to choose between stimuli. EMG eye blink responses were recorded in both anticipation and stimulus viewing. Results indicated a significant attenuation of the startle magnitude in choice condition trials (relative to no-choice) across all picture categories and probe times. We interpret these findings as an indication that the act of choice may decrease one's defensive response, or conversely, lacking choice may heighten the defensive response. Implications for future research are discussed. Copyright © 2012 Elsevier B.V. All rights reserved.

Numerical simulation of the supersonic boundary layer interaction with arbitrary oriented acoustic waves

NASA Astrophysics Data System (ADS)

Semenov, A. N.; Gaponov, S. A.

2017-10-01

Based the direct numerical simulation in the paper the supersonic flow around of the infinitely thin plate, which was perturbed by the acoustic wave, was investigated. Calculations carried out in the case of small perturbations at the Mach number M=2 and Reynold's numbers Re<600. It is established that the velocity perturbation amplitude within the boundary layer is greater than the amplitude of the external acoustic wave in several times, the maximum amplitude growth is reached 10. At the small sliding and incidence angles the velocity perturbations amplitude increased monotonously with Reynold's numbers. At rather great values of these angles there are maxima in dependences of the velocity perturbations amplitude on the Reynold's number. The oscillations exaltation in the boundary layer by the sound wave more efficiently if the plate is irradiated from above. At the fixed Reynolds's number and frequency there are critical values of the sliding and incidence angles (χ, φ) at which the disturbances excited by a sound wave are maxima. At M=2 it takes place at χ≈ φ ≈30°. The excitation efficiency of perturbations in the boundary layer increases with the Mach number, and it decreases with a frequency.

Large eddy simulations of a transcritical round jet submitted to transverse acoustic modulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gonzalez-Flesca, M.; CNES DLA, 52 Rue Jacques Hillairet, 75612 Paris Cedex; Schmitt, T.

This article reports numerical computations of a turbulent round jet of transcritical fluid (low temperature nitrogen injected under high pressure conditions) surrounded by the same fluid at rest under supercritical conditions (high temperature and high pressure) and submitted to transverse acoustic modulations. The numerical framework relies on large eddy simulation in combination with a real-gas description of thermodynamics and transport properties. A stationary acoustic field is obtained by modulating the normal acoustic velocity at the lateral boundaries of the computational domain. This study specifically focuses on the interaction of the jet with the acoustic field to investigate how the roundmore » transcritical jet changes its shape and mixes with the surrounding fluid. Different modulation amplitudes and frequencies are used to sweep a range of conditions. When the acoustic field is established in the domain, the jet length is notably reduced and the jet is flattened in the spanwise direction. Two regimes of oscillation are identified: for low Strouhal numbers a large amplitude motion is observed, while for higher Strouhal numbers the jet oscillates with a small amplitude around the injector axis. The minimum length is obtained for a Strouhal number of 0.3 and the jet length increases with increasing Strouhal numbers after reaching this minimum value. The mechanism of spanwise deformation is shown to be linked with dynamical effects resulting from reduction of the pressure in the transverse direction in relation with increased velocities on the two sides of the jet. A propagative wave is then introduced in the domain leading to similar effects on the jet, except that a bending is also observed in the acoustic propagation direction. A kinematic model, combining hydrodynamic and acoustic contributions, is derived in a second stage to represent the motion of the jet centerline. This model captures details of the numerical simulations quite well. These

The characters of ion acoustic rogue waves in nonextensive plasma

NASA Astrophysics Data System (ADS)

Du, Hai-su; Lin, Mai-mai; Gong, Xue; Duan, Wen-shan

2017-10-01

Several well-known nonlinear waves in the rational solutions of the nonlinear Schrödinger equation are studied in two-component plasmas consisting of ions fluid and nonextensive electrons, such as Kuznetsov-Ma breather (K-M), bright soliton, rogue wave (RW), Akhmediev breather (AB) and dark soliton, and so on. In this paper, we have investigated the characteristics of K-M, AB, and RW's propagation in plasma with nonextensive electron distribution, and the dependence of amplitude and width for ion acoustic rogue waves in this system. It is found that K-M' triplet is appearance-disappearance-appearance-disappearance. AB solitons only appear once and RW is a single wave that appears from nowhere and then disappears. It is also noted that the wave number and nonextensive parameter of electrons have a significant influence on the maximum envelope amplitude, but, the influence of the width was not significant. At the same time, the effects of the small parameter, which represent the nonlinear strength, on the amplitude and width of ion acoustic rogue waves are also being highlighted.

Processing emotions: Effects of menstrual cycle phase and premenstrual symptoms on the startle reflex, facial EMG and heart rate.

PubMed

Armbruster, Diana; Grage, Tobias; Kirschbaum, Clemens; Strobel, Alexander

2018-10-01

Emotional reactivity varies across the menstrual cycle although physiological findings are not entirely consistent. We assessed facial EMG and heart rate (HR) changes in healthy free cycling women (N = 45) with an emotional startle paradigm both during the early follicular and the late luteal phase, verified by repeated salivary 17β-estradiol, progesterone and testosterone assessments. Cycle phase impacted startle responses with larger magnitudes during the luteal phase. Notably, this effect was only present when premenstrual symptoms and sequence of lab sessions were included as co-variates. At rest, participants showed a tendency towards higher HR and reduced high frequency (HF) power during the luteal phase indicating reduced parasympathetic tone. HF power was also negatively associated with startle magnitudes. HR changes in response to emotional images differed between the two cycle phases. Initial HR deceleration was more marked during the follicular phase particularly when viewing negative pictures. However, cycle phase did not significantly impact corrugator and zygomaticus activity in response to emotional pictures. Among the three gonadal steroids, correlation patterns were most consistent for testosterone. During the follicular phase, testosterone was associated with zygomaticus activity while viewing neutral or positive pictures and with less pronounced HR deceleration in response to negative images. During the luteal phase, testosterone was negatively associated with fear potentiated startle. The findings underscore the importance of considering menstrual cycle phase when investigating physiological indicators of emotion. However, the modulating effect of premenstrual symptoms also emphasizes potential inter-individual differences. Copyright © 2018 Elsevier B.V. All rights reserved.

Double dissociation in the neural substrates of acute opiate dependence as measured by withdrawal-potentiated startle.

PubMed

Harris, A C; Atkinson, D M; Aase, D M; Gewirtz, J C

2006-01-01

The basolateral amygdala and portions of the "extended" amygdala (i.e. central nucleus of the amygdala, bed nucleus of the stria terminalis and shell of the nucleus accumbens) have been implicated in the aversive aspects of withdrawal from chronic opiate administration. Given that similar withdrawal signs are observed following a single opiate exposure, these structures may also play a role in "acute opiate dependence." In the current study, drug-naïve rats underwent naloxone-precipitated withdrawal from acute morphine (10 mg/kg) exposure on two successive days. On either the first or second day of testing, the basolateral amygdala, central nucleus of the amygdala, bed nucleus of the stria terminalis, or nucleus accumbens was temporarily inactivated immediately prior to naloxone injection by microinfusion of the glutamatergic alpha-amino-3-hydroxy-5-methyl-4-isoxazole proprionic acid receptor antagonist 1,2,3,4-tetrahydro-6-nitro-2,3-dioxo-benzo(f)quinoxaline-7-sulfonamide (3 microg/0.5 microl). On the first day, inactivation of the basolateral amygdala, central nucleus of the amygdala, or bed nucleus of the stria terminalis, but not the nucleus accumbens blocked withdrawal-potentiated startle, a behavioral measure of the anxiogenic effects of withdrawal. On the second day, inactivation of the nucleus accumbens, but not the basolateral amygdala, central nucleus of the amygdala, or bed nucleus of the stria terminalis disrupted the withdrawal effect. Effects of structural inactivations on withdrawal-potentiated startle were not influenced by differences in withdrawal severity on the two days of testing. A fear-potentiated startle procedure provided functional confirmation of correct cannulae placement in basolateral amygdale- and central nucleus of the amygdala-implanted animals. Our findings indicate a double dissociation in the neural substrates of withdrawal-potentiated startle following a first versus second morphine exposure, and may reflect a reorganization of

Finite Difference Modeling of Wave Progpagation in Acoustic TiltedTI Media

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Linbin; Rector III, James W.; Hoversten, G. Michael

2005-03-21

Based on an acoustic assumption (shear wave velocity is zero) and a dispersion relation, we derive an acoustic wave equation for P-waves in tilted transversely isotropic (TTI) media (transversely isotropic media with a tilted symmetry axis). This equation has fewer parameters than an elastic wave equation in TTI media and yields an accurate description of P-wave traveltimes and spreading-related attenuation. Our TTI acoustic wave equation is a fourth-order equation in time and space. We demonstrate that the acoustic approximation allows the presence of shear waves in the solution. The substantial differences in traveltime and amplitude between data created using VTImore » and TTI assumptions is illustrated in examples.« less

Effect of static pressure on acoustic energy radiated by cavitation bubbles in viscous liquids under ultrasound.

PubMed

Yasui, Kyuichi; Towata, Atsuya; Tuziuti, Toru; Kozuka, Teruyuki; Kato, Kazumi

2011-11-01

The effect of static pressure on acoustic emissions including shock-wave emissions from cavitation bubbles in viscous liquids under ultrasound has been studied by numerical simulations in order to investigate the effect of static pressure on dispersion of nano-particles in liquids by ultrasound. The results of the numerical simulations for bubbles of 5 μm in equilibrium radius at 20 kHz have indicated that the optimal static pressure which maximizes the energy of acoustic waves radiated by a bubble per acoustic cycle increases as the acoustic pressure amplitude increases or the viscosity of the solution decreases. It qualitatively agrees with the experimental results by Sauter et al. [Ultrason. Sonochem. 15, 517 (2008)]. In liquids with relatively high viscosity (∼200 mPa s), a bubble collapses more violently than in pure water when the acoustic pressure amplitude is relatively large (∼20 bar). In a mixture of bubbles of different equilibrium radius (3 and 5 μm), the acoustic energy radiated by a 5 μm bubble is much larger than that by a 3 μm bubble due to the interaction with bubbles of different equilibrium radius. The acoustic energy radiated by a 5 μm bubble is substantially increased by the interaction with 3 μm bubbles.

Effects of the NMDA receptor antagonist memantine on the expression and development of acute opiate dependence as assessed by withdrawal-potentiated startle and hyperalgesia.

PubMed

Harris, Andrew C; Rothwell, Patrick E; Gewirtz, Jonathan C

2008-03-01

While the N-methyl-D: -aspartate (NMDA) glutamate receptor has been strongly implicated in chronic opiate dependence, relatively few studies have examined the effects of NMDA receptor antagonists on withdrawal from acute opiate exposure. The current study examined the effects of memantine, a well-tolerated NMDA receptor antagonist, on acute opiate dependence as assessed by elevations in rodent startle responding (i.e., "withdrawal-potentiated startle") and increased pain sensitivity (i.e., hyperalgesia). Administration of memantine either attenuated (5 mg/kg) or blocked (10 mg/kg) the expression of withdrawal-potentiated startle during naloxone (2.5 mg/kg)-precipitated withdrawal from a single dose of morphine sulfate (10 mg/kg). Pre-treatment with the NMDA receptor antagonist also inhibited the exacerbation of withdrawal-potentiated startle across repeated acute opiate exposures. Memantine blocked the expression of acute dependence, but was less effective in inhibiting its escalation, when hyperalgesia was used as a measure of withdrawal. These doses of memantine did not affect startle responding or nociception in otherwise drug-free animals. Data from additional control groups indicated that the effects of memantine on the expression of withdrawal were not influenced by nonspecific interactions between the NMDA antagonist and either morphine or naloxone. These findings suggest that the NMDA receptor may play a key role in the earliest stages of opiate dependence and provide further evidence that memantine may be useful for the treatment of opiate withdrawal.

Nonplanar ion acoustic waves with kappa-distributed electrons

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sahu, Biswajit

2011-06-15

Using the standard reductive perturbation technique, nonlinear cylindrical and spherical Kadomtsev-Petviashvili equations are derived for the propagation of ion acoustic solitary waves in an unmagnetized collisionless plasma with kappa distributed electrons and warm ions. The influence of kappa-distributed electrons and the effects caused by the transverse perturbation on cylindrical and spherical ion acoustic waves (IAWs) are investigated. It is observed that increase in the kappa distributed electrons (i.e., decreasing {kappa}) decreases the amplitude of the solitary electrostatic potential structures. The numerical results are presented to understand the formation of ion acoustic solitary waves with kappa-distributed electrons in nonplanar geometry. Themore » present investigation may have relevance in the study of propagation of IAWs in space and laboratory plasmas.« less

Linear Stability Analysis of an Acoustically Vaporized Droplet

NASA Astrophysics Data System (ADS)

Siddiqui, Junaid; Qamar, Adnan; Samtaney, Ravi

2015-11-01

Acoustic droplet vaporization (ADV) is a phase transition phenomena of a superheat liquid (Dodecafluoropentane, C5F12) droplet to a gaseous bubble, instigated by a high-intensity acoustic pulse. This approach was first studied in imaging applications, and applicable in several therapeutic areas such as gas embolotherapy, thrombus dissolution, and drug delivery. High-speed imaging and theoretical modeling of ADV has elucidated several physical aspects, ranging from bubble nucleation to its subsequent growth. Surface instabilities are known to exist and considered responsible for evolving bubble shapes (non-spherical growth, bubble splitting and bubble droplet encapsulation). We present a linear stability analysis of the dynamically evolving interfaces of an acoustically vaporized micro-droplet (liquid A) in an infinite pool of a second liquid (liquid B). We propose a thermal ADV model for the base state. The linear analysis utilizes spherical harmonics (Ynm, of degree m and order n) and under various physical assumptions results in a time-dependent ODE of the perturbed interface amplitudes (one at the vapor/liquid A interface and the other at the liquid A/liquid B interface). The perturbation amplitudes are found to grow exponentially and do not depend on m. Supported by KAUST Baseline Research Funds.

Pen-chant: Acoustic emissions of handwriting and drawing

NASA Astrophysics Data System (ADS)

Seniuk, Andrew G.

The sounds generated by a writing instrument ('pen-chant') provide a rich and underutilized source of information for pattern recognition. We examine the feasibility of recognition of handwritten cursive text, exclusively through an analysis of acoustic emissions. We design and implement a family of recognizers using a template matching approach, with templates and similarity measures derived variously from: smoothed amplitude signal with fixed resolution, discrete sequence of magnitudes obtained from peaks in the smoothed amplitude signal, and ordered tree obtained from a scale space signal representation. Test results are presented for recognition of isolated lowercase cursive characters and for whole words. We also present qualitative results for recognizing gestures such as circling, scratch-out, check-marks, and hatching. Our first set of results, using samples provided by the author, yield recognition rates of over 70% (alphabet) and 90% (26 words), with a confidence of +/-8%, based solely on acoustic emissions. Our second set of results uses data gathered from nine writers. These results demonstrate that acoustic emissions are a rich source of information, usable---on their own or in conjunction with image-based features---to solve pattern recognition problems. In future work, this approach can be applied to writer identification, handwriting and gesture-based computer input technology, emotion recognition, and temporal analysis of sketches.

Psychosocial stress alters the strength of reticulospinal input to the human upper trapezius.

PubMed

Marker, Ryan J; Campeau, Serge; Maluf, Katrina S

2017-01-01

Psychosocial stress has been shown to influence several aspects of human motor control associated with the fight-or-flight response, including augmentation of upper trapezius muscle activity. Given the established role of the reticular formation in arousal, this study investigated the contribution of reticulospinal activation to trapezius muscle activity during exposure to an acute psychosocial stressor. Twenty-five healthy adults were exposed to startling acoustic stimuli (SAS) while performing a motor task during periods of low and high psychosocial stress. Acoustic startle reflexes (ASRs) were recorded in the upper trapezius during low intensity contractions using both surface and intramuscular electromyography. Exposure to the stressor increased subjective and physiological measures of arousal (P < 0.01). The majority of participants demonstrated inhibitory ASRs, whereas a small subgroup with significantly higher trait anxiety (n = 5) demonstrated excitatory ASRs in the low stress condition. Changes in synaptic input for inhibitory ASRs were confirmed by decreases in the discharge rate of single motor units in response to the SAS. ASRs decreased in magnitude for all participants during exposure to the acute psychosocial stressor. These findings suggest that the reticular formation has predominately inhibitory effects on the human upper trapezius during an ongoing motor task and that disinhibition caused by psychosocial stress may contribute to augmentation of trapezius muscle activity. Further research is required to investigate mechanisms underlying the complex ASRs characterized by this study, particularly the phase reversal to excitatory responses observed among more anxious individuals. This study is the first to quantify stress-evoked changes in the acoustic startle reflex in the upper trapezius muscle of humans, and our findings reveal a complex pattern of inhibitory and facilitatory responses consistent with observations in nonhuman primates. We further

Psychosocial stress alters the strength of reticulospinal input to the human upper trapezius

PubMed Central

Marker, Ryan J.; Campeau, Serge

2016-01-01

Psychosocial stress has been shown to influence several aspects of human motor control associated with the fight-or-flight response, including augmentation of upper trapezius muscle activity. Given the established role of the reticular formation in arousal, this study investigated the contribution of reticulospinal activation to trapezius muscle activity during exposure to an acute psychosocial stressor. Twenty-five healthy adults were exposed to startling acoustic stimuli (SAS) while performing a motor task during periods of low and high psychosocial stress. Acoustic startle reflexes (ASRs) were recorded in the upper trapezius during low intensity contractions using both surface and intramuscular electromyography. Exposure to the stressor increased subjective and physiological measures of arousal (P < 0.01). The majority of participants demonstrated inhibitory ASRs, whereas a small subgroup with significantly higher trait anxiety (n = 5) demonstrated excitatory ASRs in the low stress condition. Changes in synaptic input for inhibitory ASRs were confirmed by decreases in the discharge rate of single motor units in response to the SAS. ASRs decreased in magnitude for all participants during exposure to the acute psychosocial stressor. These findings suggest that the reticular formation has predominately inhibitory effects on the human upper trapezius during an ongoing motor task and that disinhibition caused by psychosocial stress may contribute to augmentation of trapezius muscle activity. Further research is required to investigate mechanisms underlying the complex ASRs characterized by this study, particularly the phase reversal to excitatory responses observed among more anxious individuals. NEW & NOTEWORTHY This study is the first to quantify stress-evoked changes in the acoustic startle reflex in the upper trapezius muscle of humans, and our findings reveal a complex pattern of inhibitory and facilitatory responses consistent with observations in nonhuman

Holograms for acoustics.

PubMed

Melde, Kai; Mark, Andrew G; Qiu, Tian; Fischer, Peer

2016-09-22

Holographic techniques are fundamental to applications such as volumetric displays, high-density data storage and optical tweezers that require spatial control of intricate optical or acoustic fields within a three-dimensional volume. The basis of holography is spatial storage of the phase and/or amplitude profile of the desired wavefront in a manner that allows that wavefront to be reconstructed by interference when the hologram is illuminated with a suitable coherent source. Modern computer-generated holography skips the process of recording a hologram from a physical scene, and instead calculates the required phase profile before rendering it for reconstruction. In ultrasound applications, the phase profile is typically generated by discrete and independently driven ultrasound sources; however, these can only be used in small numbers, which limits the complexity or degrees of freedom that can be attained in the wavefront. Here we introduce monolithic acoustic holograms, which can reconstruct diffraction-limited acoustic pressure fields and thus arbitrary ultrasound beams. We use rapid fabrication to craft the holograms and achieve reconstruction degrees of freedom two orders of magnitude higher than commercial phased array sources. The technique is inexpensive, appropriate for both transmission and reflection elements, and scales well to higher information content, larger aperture size and higher power. The complex three-dimensional pressure and phase distributions produced by these acoustic holograms allow us to demonstrate new approaches to controlled ultrasonic manipulation of solids in water, and of liquids and solids in air. We expect that acoustic holograms will enable new capabilities in beam-steering and the contactless transfer of power, improve medical imaging, and drive new applications of ultrasound.

Three-dimensional manipulation of single cells using surface acoustic waves

PubMed Central

Guo, Feng; Mao, Zhangming; Chen, Yuchao; Xie, Zhiwei; Lata, James P.; Li, Peng; Ren, Liqiang; Liu, Jiayang; Yang, Jian; Dao, Ming; Suresh, Subra; Huang, Tony Jun

2016-01-01

The ability of surface acoustic waves to trap and manipulate micrometer-scale particles and biological cells has led to many applications involving “acoustic tweezers” in biology, chemistry, engineering, and medicine. Here, we present 3D acoustic tweezers, which use surface acoustic waves to create 3D trapping nodes for the capture and manipulation of microparticles and cells along three mutually orthogonal axes. In this method, we use standing-wave phase shifts to move particles or cells in-plane, whereas the amplitude of acoustic vibrations is used to control particle motion along an orthogonal plane. We demonstrate, through controlled experiments guided by simulations, how acoustic vibrations result in micromanipulations in a microfluidic chamber by invoking physical principles that underlie the formation and regulation of complex, volumetric trapping nodes of particles and biological cells. We further show how 3D acoustic tweezers can be used to pick up, translate, and print single cells and cell assemblies to create 2D and 3D structures in a precise, noninvasive, label-free, and contact-free manner. PMID:26811444

Three-dimensional manipulation of single cells using surface acoustic waves.

PubMed

Guo, Feng; Mao, Zhangming; Chen, Yuchao; Xie, Zhiwei; Lata, James P; Li, Peng; Ren, Liqiang; Liu, Jiayang; Yang, Jian; Dao, Ming; Suresh, Subra; Huang, Tony Jun

2016-02-09

The ability of surface acoustic waves to trap and manipulate micrometer-scale particles and biological cells has led to many applications involving "acoustic tweezers" in biology, chemistry, engineering, and medicine. Here, we present 3D acoustic tweezers, which use surface acoustic waves to create 3D trapping nodes for the capture and manipulation of microparticles and cells along three mutually orthogonal axes. In this method, we use standing-wave phase shifts to move particles or cells in-plane, whereas the amplitude of acoustic vibrations is used to control particle motion along an orthogonal plane. We demonstrate, through controlled experiments guided by simulations, how acoustic vibrations result in micromanipulations in a microfluidic chamber by invoking physical principles that underlie the formation and regulation of complex, volumetric trapping nodes of particles and biological cells. We further show how 3D acoustic tweezers can be used to pick up, translate, and print single cells and cell assemblies to create 2D and 3D structures in a precise, noninvasive, label-free, and contact-free manner.

Introversion and individual differences in middle ear acoustic reflex function.

PubMed

Bar-Haim, Yair

2002-10-01

A growing body of psychophysiological evidence points to the possibility that individual differences in early auditory processing may contribute to social withdrawal and introverted tendencies. The present study assessed the response characteristics of the acoustic reflex arc of introverted-withdrawn and extraverted-sociable individuals. Introverts displayed a greater incidence of abnormal middle ear acoustic reflexes and lower acoustic reflex amplitudes than extraverts. These findings were strongest for stimuli presented at a frequency of 2000 Hz. Results are discussed in light of the controversy concerning the anatomic loci (peripheral vs. central neuronal activity) of the individual differences between introverts and extraverts in early auditory processing. Copyright 2002 Elsevier Science B.V.

Solving transient acoustic boundary value problems with equivalent sources using a lumped parameter approach.

PubMed

Fahnline, John B

2016-12-01

An equivalent source method is developed for solving transient acoustic boundary value problems. The method assumes the boundary surface is discretized in terms of triangular or quadrilateral elements and that the solution is represented using the acoustic fields of discrete sources placed at the element centers. Also, the boundary condition is assumed to be specified for the normal component of the surface velocity as a function of time, and the source amplitudes are determined to match the known elemental volume velocity vector at a series of discrete time steps. Equations are given for marching-on-in-time schemes to solve for the source amplitudes at each time step for simple, dipole, and tripole source formulations. Several example problems are solved to illustrate the results and to validate the formulations, including problems with closed boundary surfaces where long-time numerical instabilities typically occur. A simple relationship between the simple and dipole source amplitudes in the tripole source formulation is derived so that the source radiates primarily in the direction of the outward surface normal. The tripole source formulation is shown to eliminate interior acoustic resonances and long-time numerical instabilities.

Time domain localization technique with sparsity constraint for imaging acoustic sources

NASA Astrophysics Data System (ADS)

Padois, Thomas; Doutres, Olivier; Sgard, Franck; Berry, Alain

2017-09-01

This paper addresses source localization technique in time domain for broadband acoustic sources. The objective is to accurately and quickly detect the position and amplitude of noise sources in workplaces in order to propose adequate noise control options and prevent workers hearing loss or safety risk. First, the generalized cross correlation associated with a spherical microphone array is used to generate an initial noise source map. Then a linear inverse problem is defined to improve this initial map. Commonly, the linear inverse problem is solved with an l2 -regularization. In this study, two sparsity constraints are used to solve the inverse problem, the orthogonal matching pursuit and the truncated Newton interior-point method. Synthetic data are used to highlight the performances of the technique. High resolution imaging is achieved for various acoustic sources configurations. Moreover, the amplitudes of the acoustic sources are correctly estimated. A comparison of computation times shows that the technique is compatible with quasi real-time generation of noise source maps. Finally, the technique is tested with real data.

The acoustic communities: Definition, description and ecological role.

PubMed

Farina, Almo; James, Philip

2016-09-01

An acoustic community is defined as an aggregation of species that produces sound by using internal or extra-body sound-producing tools. Such communities occur in aquatic (freshwater and marine) and terrestrial environments. An acoustic community is the biophonic component of a soundtope and is characterized by its acoustic signature, which results from the distribution of sonic information associated with signal amplitude and frequency. Distinct acoustic communities can be described according to habitat, the frequency range of the acoustic signals, and the time of day or the season. Near and far fields can be identified empirically, thus the acoustic community can be used as a proxy for biodiversity richness. The importance of ecoacoustic research is rapidly growing due to the increasing awareness of the intrusion of anthropogenic sounds (technophonies) into natural and human-modified ecosystems and the urgent need to adopt more efficient predictive tools to compensate for the effects of climate change. The concept of an acoustic community provides an operational scale for a non-intrusive biodiversity survey and analysis that can be carried out using new passive audio recording technology, coupled with methods of vast data processing and storage. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Analysis of the effect of a rectangular cavity resonator on acoustic wave transmission in a waveguide

NASA Astrophysics Data System (ADS)

Porter, R.; Evans, D. V.

2017-11-01

The transmission of acoustic waves along a two-dimensional waveguide which is coupled through an opening in its wall to a rectangular cavity resonator is considered. The resonator acts as a classical band-stop filter, significantly reducing acoustic transmission across a range of frequencies. Assuming wave frequencies below the first waveguide cut-off, the solution for the reflected and transmitted wave amplitudes is formulated exactly within the framework of inviscid linear acoustics. The main aim of the paper is to develop an approximation in closed form for reflected and transmitted amplitudes when the gap in the thin wall separating the waveguide and the cavity resonator is assumed to be small. This approximation is shown to accurately capture the effect of all cavities resonances, not just the fundamental Helmholtz resonance. It is envisaged this formula (and more generally the mathematical approach adopted) could be used in the development of acoustic metamaterial devices containing resonator arrays.

Generation and development of small-amplitude disturbances in a laminar boundary layer in the presence of an acoustic field

NASA Technical Reports Server (NTRS)

Kachanov, Y. S.; Kozlov, V. V.; Levchenko, V. Y.

1985-01-01

A low-turbulence subsonic wind tunnel was used to study the influence of acoustic disturbances on the development of small sinusoidal oscillations (Tollmien-Schlichting waves) which constitute the initial phase of turbulent transition. It is found that acoustic waves propagating opposite to the flow generate vibrations of the model (plate) in the flow. Neither the plate vibrations nor the acoustic field itself have any appreciable influence on the stability of the laminar boundary layer. The influence of an acoustic field on laminar boundary layer disturbances is limited to the generation of Tollmien-Schlichting waves at the leading-edge of the plate.

Non-linear effects in finite amplitude wave propagation through ducts and nozzles

NASA Technical Reports Server (NTRS)

Salikuddin, M.; Brown, W. H.

1986-01-01

In this paper an extensive study of non-linear effects in finite amplitude wave propagation through ducts and nozzles is summarized. Some results from earlier studies are included to illustrate the non-linear effects on the transmission characteristics of duct and nozzle terminations. Investigaiations, both experimental and analytical, were carried out to determine the magnitudes of the effects for high intensity pulse propagation. The results derived from these investigations are presented in this paper. They include the effect of the sound intensity on the acoustic characteristics of duct and nozzle terminations, the extent of the non-linearities in the propagation of high intensity impulsive sound inside the duct and out into free field, the acoustic energy dissipation mechanism at a termination as shown by flow visualizations, and quantitative evaluations by experimental and analytical means of the influence of the intensity of a sound pulse on the dissipation of its acoustic power.

Longitudinal and Transverse Instability of Ion Acoustic Waves

NASA Astrophysics Data System (ADS)

Chapman, T.; Berger, R. L.; Cohen, B. I.; Banks, J. W.; Brunner, S.

2017-08-01

Ion acoustic waves are found to be susceptible to at least two distinct decay processes. Which process dominates depends on the parameters. In the cases examined, the decay channel where daughter modes propagate parallel to the mother mode is found to dominate at larger amplitudes, while the decay channel where the daughter modes propagate at angles to the mother mode dominates at smaller amplitudes. Both decay processes may occur simultaneously and with onset thresholds below those suggested by fluid theory, resulting in the eventual multidimensional collapse of the mother mode to a turbulent state.

Auditory sensitivity of larval zebrafish (Danio rerio) measured using a behavioral prepulse inhibition assay

PubMed Central

Bhandiwad, Ashwin A.; Zeddies, David G.; Raible, David W.; Rubel, Edwin W.; Sisneros, Joseph A.

2013-01-01

SUMMARY Zebrafish (Danio rerio) have become a valuable model for investigating the molecular genetics and development of the inner ear in vertebrates. In this study, we employed a prepulse inhibition (PPI) paradigm to assess hearing in larval wild-type (AB) zebrafish during early development at 5–6 days post-fertilization (d.p.f.). We measured the PPI of the acoustic startle response in zebrafish using a 1-dimensional shaker that simulated the particle motion component of sound along the fish's dorsoventral axis. The thresholds to startle-inducing stimuli were determined in 5–6 d.p.f. zebrafish, and their hearing sensitivity was then characterized using the thresholds of prepulse tone stimuli (90–1200 Hz) that inhibited the acoustic startle response to a reliable startle stimulus (820 Hz at 20 dB re. 1 m s−2). Hearing thresholds were defined as the minimum prepulse tone level required to significantly reduce the startle response probability compared with the baseline (no-prepulse) condition. Larval zebrafish showed greatest auditory sensitivity from 90 to 310 Hz with corresponding mean thresholds of −19 to −10 dB re. 1 m s−2, respectively. Hearing thresholds of prepulse tones were considerably lower than previously predicted by startle response assays. The PPI assay was also used to investigate the relative contribution of the lateral line to the detection of acoustic stimuli. After aminoglycoside-induced neuromast hair-cell ablation, we found no difference in PPI thresholds between treated and control fish. We propose that this PPI assay can be used to screen for novel zebrafish hearing mutants and to investigate the ontogeny of hearing in zebrafish and other fishes. PMID:23966590

Acoustic response of vortex breakdown modes in a coaxial isothermal unconfined swirling jet

NASA Astrophysics Data System (ADS)

Santhosh, R.; Basu, Saptarshi

2015-03-01

The present experimental work is concerned with the study of amplitude dependent acoustic response of an isothermal coaxial swirling jet. The excitation amplitude is increased in five distinct steps at the burner's Helmholtz resonator mode (i.e., 100 Hz). Two flow states are compared, namely, sub-critical and super-critical vortex breakdown (VB) that occur before and after the critical conical sheet breakdown, respectively. The geometric swirl number is varied in the range 2.14-4.03. Under the influence of external pulsing, global response characteristics are studied based on the topological changes observed in time-averaged 2D flow field. These are obtained from high resolution 2D PIV (particle image velocimetry) in the longitudinal-mid plane. PIV results also illustrate the changes in the normalized vortex core coordinates (rvcc/(rvcc)0 Hz, yvcc/(yvcc)0 Hz) of internal recirculation zone (IRZ). A strong forced response is observed at 100 Hz (excitation frequency) in the convectively unstable region which get amplified based on the magnitude of external forcing. The radial extent of this forced response region at a given excitation amplitude is represented by the acoustic response region (b). The topological placement of the responsive convectively unstable region is a function of both the intensity of imparted swirl (characterized by swirl number) and forcing amplitude. It is observed that for sub-critical VB mode, an increase in the excitation amplitude till a critical value shifts the vortex core centre (particularly, the vortex core moves downstream and radially outwards) leading to drastic fanning-out/widening of the IRZ. This is accompanied by ˜30% reduction in the recirculation velocity of the IRZ. It is also observed that b < R (R: radial distance from central axis to outer shear layer-OSL). At super-critical amplitudes, the sub-critical IRZ topology transits back (the vortex core retracts upstream and radially inwards) and finally undergoes a transverse

High-speed acoustic communication by multiplexing orbital angular momentum

PubMed Central

Shi, Chengzhi; Dubois, Marc; Wang, Yuan

2017-01-01

Long-range acoustic communication is crucial to underwater applications such as collection of scientific data from benthic stations, ocean geology, and remote control of off-shore industrial activities. However, the transmission rate of acoustic communication is always limited by the narrow-frequency bandwidth of the acoustic waves because of the large attenuation for high-frequency sound in water. Here, we demonstrate a high-throughput communication approach using the orbital angular momentum (OAM) of acoustic vortex beams with one order enhancement of the data transmission rate at a single frequency. The topological charges of OAM provide intrinsically orthogonal channels, offering a unique ability to multiplex data transmission within a single acoustic beam generated by a transducer array, drastically increasing the information channels and capacity of acoustic communication. A high spectral efficiency of 8.0 ± 0.4 (bit/s)/Hz in acoustic communication has been achieved using topological charges between −4 and +4 without applying other communication modulation techniques. Such OAM is a completely independent degree of freedom which can be readily integrated with other state-of-the-art communication modulation techniques like quadrature amplitude modulation (QAM) and phase-shift keying (PSK). Information multiplexing through OAM opens a dimension for acoustic communication, providing a data transmission rate that is critical for underwater applications. PMID:28652341

STS-70 Discovery launch startled birds at ignition

NASA Technical Reports Server (NTRS)

1995-01-01

Startled birds scatter as the stillness of a summer morning is broken by a giant's roar. The Space Shuttle Discovery thundered into space from launch Pad 39-B at 9:41:55:078 a.m. EDT. STS-70 is the 70th Shuttle flight overall, the 21st for Discovery (OV- 103), and the fourth Shuttle flight in 1995. On board for the nearly eight-day mission are a crew of five: Commander Terence 'Tom' Hendricks; Pilot Kevin R. Kregel; and Mission Specialists Nancy Jane Currie, Donald A. Thomas and Mary Ellen Weber. The crew's primary objective is to deploy the Tracking and Data Relay Satellite-G (TDRS-G), which will join a constellation of other TDRS spacecraft already on orbit.

High-frequency modulation of ion-acoustic waves.

NASA Technical Reports Server (NTRS)

Albright, N. W.

1972-01-01

A large amplitude, high-frequency electromagnetic oscillation is impressed on a nonrelativistic, collisionless plasma from an external source. The frequency is chosen to be far from the plasma frequency (in fact, lower). The resulting electron velocity distribution function strongly modifies the propagation of ion-acoustic waves parallel to the oscillating electric field. The complex frequency is calculated numerically.

Sex-Related Acoustic Changes in Voiceless English Fricatives

ERIC Educational Resources Information Center

Fox, Robert Allen; Nissen, Shawn L.

2005-01-01

This investigation is a comprehensive acoustic study of 4 voiceless fricatives (/f [theta] s [esh]/) in English produced by adults and pre-and postpubescent children aged 6-14 years. Vowel duration, amplitude, and several different spectral measures (including spectral tilt and spectral moments) were examined. Of specific interest was the pattern…

Contextual-specificity of short-delay extinction in humans: Renewal of fear-potentiated startle in a virtual environment

PubMed Central

Alvarez, Ruben P.; Johnson, Linda; Grillon, Christian

2007-01-01

A recent fear-potentiated startle study in rodents suggested that extinction was not context dependent when extinction was conducted after a short delay following acquisition, suggesting that extinction can lead to erasure of fear learning in some circumstances. The main objective of this study was to attempt to replicate these findings in humans by examining the context specificity of short-delay extinction in an ABA renewal procedure using virtual reality environments. A second objective was to examine whether renewal, if any, would be influenced by context conditioning. Subjects underwent differential aversive conditioning in virtual context A, which was immediately followed by extinction in virtual context B. Extinction was followed by tests of renewal in context A and B, with the order counterbalanced across subjects. Results showed that extinction was context dependent. Evidence for renewal was established using fear-potentiated startle as well as skin conductance and fear ratings. In addition, although contextual anxiety was greater in the acquisition context than in the extinction context during renewal, as assessed with startle, context conditioning did not influence the renewal effect. These data do not support the view that extinction conducted shortly after acquisition is context independent. Hence, they do not provide evidence that extinction can lead to erasure of a fear memory established via Pavlovian conditioning. PMID:17412963

Power cepstrum technique with application to model helicopter acoustic data

NASA Technical Reports Server (NTRS)

Martin, R. M.; Burley, C. L.

1986-01-01

The application of the power cepstrum to measured helicopter-rotor acoustic data is investigated. A previously applied correction to the reconstructed spectrum is shown to be incorrect. For an exact echoed signal, the amplitude of the cepstrum echo spike at the delay time is linearly related to the echo relative amplitude in the time domain. If the measured spectrum is not entirely from the source signal, the cepstrum will not yield the desired echo characteristics and a cepstral aliasing may occur because of the effective sample rate in the frequency domain. The spectral analysis bandwidth must be less than one-half the echo ripple frequency or cepstral aliasing can occur. The power cepstrum editing technique is a useful tool for removing some of the contamination because of acoustic reflections from measured rotor acoustic spectra. The cepstrum editing yields an improved estimate of the free field spectrum, but the correction process is limited by the lack of accurate knowledge of the echo transfer function. An alternate procedure, which does not require cepstral editing, is proposed which allows the complete correction of a contaminated spectrum through use of both the transfer function and delay time of the echo process.

Oblique collision of dust acoustic solitons in a strongly coupled dusty plasma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boruah, A.; Sharma, S. K., E-mail: sumita-sharma82@yahoo.com; Bailung, H.

2015-09-15

The oblique collision between two equal amplitude dust acoustic solitons is observed in a strongly coupled dusty plasma. The solitons are subjected to oblique interaction at different colliding angles. We observe a resonance structure during oblique collision at a critical colliding angle which is described by the idea of three wave resonance interaction modeled by Kadomtsev-Petviashvili equation. After collision, the solitons preserve their identity. The amplitude of the resultant wave formed during interaction is measured for different collision angles as well as for different colliding soliton amplitudes. At resonance, the maximum amplitude of the new soliton formed is nearly 3.7more » times the initial soliton amplitude.« less

The influence of pitch and loudness changes on the acoustics of vocal tremor.

PubMed

Dromey, Christopher; Warrick, Paul; Irish, Jonathan

2002-10-01

The effect of tremor on phonation is to modulate an otherwise steady sound source in its amplitude, fundamental frequency, or both. The severity of untreated vocal tremor has been reported to change under certain conditions that may be related to muscle tension. In order to better understand the phenomenon of vocal tremor, its acoustic properties were examined as individuals volitionally altered their pitch and loudness. These voice conditions were anticipated to alter the tension of the intrinsic laryngeal muscles. The voices of 10 individuals with a diagnosis of vocal tremor were recorded before participating in a longitudinal treatment study. They produced vowels at low and high pitch and loudness levels as well as in a comfortable voice condition. Acoustic analyses quantified the amplitude and frequency modulations of the speakers' voices across the various conditions. Individual speakers varied in the way the pitch and loudness changes affected their tremor, but the following statistically significant effects for the speakers as a group were observed: Higher pitch phonation was associated with a more rapid rate for both amplitude and frequency modulations. Amplitude modulation become faster for louder phonation. Low-pitched phonotion led to decreases in the extent of amplitude tremor. Varying pitch led to dramatic changes in the phase relationship between amplitude and frequency modulation in some of the speakers, whereas this effect was not apparent in other speakers.

The effects of Eph-ephrin mutations on pre-pulse inhibition in mice.

PubMed

Liuzzo, Andrea; Gray, Lincoln; Wallace, Matthew; Gabriele, Mark

2014-08-01

Eph-ephrin signaling is known to be important in directing topographic projections in the afferent auditory pathway, including connections to various subdivisions of the inferior colliculus (IC). The acoustic startle-response (ASR) is a reliable reflexive behavioral response in mammals elicited by an unexpected intense acoustic startle-eliciting stimulus (ES). It is mediated by a sub-cortical pathway that includes the IC. The ASR amplitude can be measured with an accelerometer under the subject and can be decreased in amplitude by presenting a less intense, non-startling stimulus 5-300ms before the ES. This reflexive decrement in ASR is called pre-pulse inhibition (PPI) and indicates that the relatively soft pre-pulse was heard. PPI is a general trait among mammals. Mice have been used recently to study this response and to reveal how genetic mutations affect neural circuits and hence the ASR and PPI. In this experiment, we measured the effect of Eph-ephrin mutations using control mice (C57BL/6J), mice with compromised EphA4 signaling (EphA4(lacZ/+), EphA4(lacZ/lacZ)), and knockout ephrin-B3 mice (ephrin-B3 (+/-, -/-)). Control and EphA4(lacZ/+s)trains showed robust PPI (up to 75% decrement in ASR) to an offset of a 70dB SPL background noise at 50ms before the ES. Ephrin-B3 knockout mice and EphA4 homozygous mutants were only marginally significant in PPI (<25% decrement and <33% decrement, respectively) to the same conditions. This decrement in PPI highlights the importance of ephrin-B3 and EphA4 interactions in ordering auditory behavioral circuits. Thus, different mutations in certain members of the signaling family produce a full range of changes in PPI, from minimal to nearly maximal. This technique can be easily adapted to study other aspects of hearing in a wider range of mutations. Along with ongoing neuroanatomical studies, this allows careful quantification of how the auditory anatomical, physiological and now behavioral phenotype is affected by changes

Impedance matched joined drill pipe for improved acoustic transmission

DOEpatents

Moss, William C.

2000-01-01

An impedance matched jointed drill pipe for improved acoustic transmission. A passive means and method that maximizes the amplitude and minimize the temporal dispersion of acoustic signals that are sent through a drill string, for use in a measurement while drilling telemetry system. The improvement in signal transmission is accomplished by replacing the standard joints in a drill string with joints constructed of a material that is impedance matched acoustically to the end of the drill pipe to which it is connected. Provides improvement in the measurement while drilling technique which can be utilized for well logging, directional drilling, and drilling dynamics, as well as gamma-ray spectroscopy while drilling post shot boreholes, such as utilized in drilling post shot boreholes.

Numerical Investigations of High Pressure Acoustic Waves in Resonators

NASA Technical Reports Server (NTRS)

Athavale, Mahesh; Pindera, Maciej; Daniels, Christopher C.; Steinetz, Bruce M.

2004-01-01

This presentation presents work on numerical investigations of nonlinear acoustic phenomena in resonators that can generate high-pressure waves using acoustic forcing of the flow. Time-accurate simulations of the flow in a closed cone resonator were performed at different oscillation frequencies and amplitudes, and the numerical results for the resonance frequency and fluid pressure increase match the GRC experimental data well. Work on cone resonator assembly simulations has started and will involve calculations of the flow through the resonator assembly with and without acoustic excitation. A new technique for direct calculation of resonance frequency of complex shaped resonators is also being investigated. Script-driven command procedures will also be developed for optimization of the resonator shape for maximum pressure increase.

Correlating Inertial Acoustic Cavitation Emissions with Material Erosion Resistance

NASA Astrophysics Data System (ADS)

Ibanez, I.; Hodnett, M.; Zeqiri, B.; Frota, M. N.

The standard ASTM G32-10 concerns the hydrodynamic cavitation erosion resistance of materials by subjecting them to acoustic cavitation generated by a sonotrode. The work reported extends this technique by detecting and monitoring the ultrasonic cavitation, considered responsible for the erosion process, specifically for coupons of aluminium-bronze alloy. The study uses a 65 mm diameter variant of NPL's cavitation sensor, which detects broadband acoustic emissions, and logs acoustic signals generated in the MHz frequency range, using NPL's Cavimeter. Cavitation readings were made throughout the exposure duration, which was carried out at discrete intervals (900 to 3600 s), allowing periodic mass measurements to be made to assess erosion loss under a strict protocol. Cavitation measurements and erosion were compared for different separations of the sonotrode tip from the material under test. The maximum variation associated with measurement of cavitation level was between 2.2% and 3.3% when the separation (λ) between the transducer horn and the specimen increased from 0.5 to 1.0 mm, for a transducer (sonotrode) displacement amplitude of 43.5 μm. Experiments conducted at the same transducer displacement amplitude show that the mass loss of the specimen -a measure of erosion- was 67.0 mg (λ = 0.5 mm) and 66.0 mg (λ = 1.0 mm).

Model helicopter rotor high-speed impulsive noise: Measured acoustics and blade pressures

NASA Technical Reports Server (NTRS)

Boxwell, D. A.; Schmitz, F. H.; Splettstoesser, W. R.; Schultz, K. J.

1983-01-01

A 1/17-scale research model of the AH-1 series helicopter main rotor was tested. Model-rotor acoustic and simultaneous blade pressure data were recorded at high speeds where full-scale helicopter high-speed impulsive noise levels are known to be dominant. Model-rotor measurements of the peak acoustic pressure levels, waveform shapes, and directively patterns are directly compared with full-scale investigations, using an equivalent in-flight technique. Model acoustic data are shown to scale remarkably well in shape and in amplitude with full-scale results. Model rotor-blade pressures are presented for rotor operating conditions both with and without shock-like discontinuities in the radiated acoustic waveform. Acoustically, both model and full-scale measurements support current evidence that above certain high subsonic advancing-tip Mach numbers, local shock waves that exist on the rotor blades ""delocalize'' and radiate to the acoustic far-field.

Nonlinear acoustic spectroscopy of cracked flaws and disbonds: Fundamentals, techniques, and applications

NASA Astrophysics Data System (ADS)

Maev, R. Gr.; Solodov, I. Yu.

2000-05-01

Classical nonlinear acoustics of solids operates with distributed material nonlinearity related to unharmonicity of molecular interaction forces. Weakening of molecular bonds in a defect area or intermittent lack of elastic coupling between the faces of a vibrating crack or unbond ("clapping") results in anomalously high local contact acoustic nonlinearity (CAN). CAN properties and spectral features are different from those of the classical analog and important to develop new acoustic NDE techniques. Three approaches to nonlinear NDE methodology have been experimentally verified: low-frequency (hundreds of Hz) vibration technique, intermediate-frequency (hundreds of kHz) standing wave and high-frequency (tens of MHz) propagation modes. Low-frequency nonlinear contact vibrations revealed multiple sub- and super-harmonics generation featuring non-monotonous (sinx/x type) spectra. Parametric instability observed in resonator with a nonlinear contact leads to the output spectrum splitting up into successive sub-harmonics as the wave amplitude increases. High-frequency experiments demonstrated abnormal increases in the third harmonic amplitude: 3 or 4 order enhancement of the 3-ω nonlinear parameter was measured for the nonlinear contact. The CAN spectral features in both acoustic and vibration modes were used for nonlinear NDE of simulated and realistic flaws in glass, metal welds, etc. The sensitivities of the techniques are compared and their practical applicability assessed.

The effect of buildings on acoustic pulse propagation in an urban environment.

PubMed

Albert, Donald G; Liu, Lanbo

2010-03-01

Experimental measurements were conducted using acoustic pulse sources in a full-scale artificial village to investigate the reverberation, scattering, and diffraction produced as acoustic waves interact with buildings. These measurements show that a simple acoustic source pulse is transformed into a complex signature when propagating through this environment, and that diffraction acts as a low-pass filter on the acoustic pulse. Sensors located in non-line-of-sight (NLOS) positions usually recorded lower positive pressure maxima than sensors in line-of-sight positions. Often, the first arrival on a NLOS sensor located around a corner was not the largest arrival, as later reflection arrivals that traveled longer distances without diffraction had higher amplitudes. The waveforms are of such complexity that human listeners have difficulty identifying replays of the signatures generated by a single pulse, and the usual methods of source location based on the direction of arrivals may fail in many cases. Theoretical calculations were performed using a two-dimensional finite difference time domain (FDTD) method and compared to the measurements. The predicted peak positive pressure agreed well with the measured amplitudes for all but two sensor locations directly behind buildings, where the omission of rooftop ray paths caused the discrepancy. The FDTD method also produced good agreement with many of the measured waveform characteristics.

Transverse acoustic forcing of a round hydrodynamically self-excited jet

NASA Astrophysics Data System (ADS)

Kushwaha, Abhijit Kumar; Mazur, Marek; Worth, Nicholas; Dawson, James; Li, Larry K. B.

2017-11-01

Hydrodynamically self-excited jets can readily synchronize with longitudinal acoustic forcing, but their response to transverse acoustic forcing is less clear. In this experimental study, we apply transverse acoustic forcing to an axisymmetric low-density jet at frequencies around its natural global frequency. We place the jet in a rectangular box containing two loudspeakers, one at each end, producing nominally one-dimensional standing pressure waves. By traversing the jet across this box, we subject it to a range of acoustic modes, from purely longitudinal (streamwise) modes at the pressure anti-node to purely transverse (cross-stream) modes at the pressure node. Using time-resolved Background-Oriented Schlieren (BOS) imaging and hot-wire anemometry, we characterize the jet response for different forcing frequencies, amplitudes and mode shapes, providing new insight into the way transverse acoustic oscillations interact with axisymmetric hydrodynamic oscillations. This work was supported by the Research Grants Council of Hong Kong (Project No. 16235716 and 26202815).

Remote Acoustic Emission Monitoring of Metal Ware and Welded Joints

NASA Astrophysics Data System (ADS)

Kapranov, Boris I.; Sutorikhin, Vladimir A.

2017-10-01

An unusual phenomenon was revealed in the metal-ultrasound interaction. Microwave sensor generates surface electric conductivity oscillations from exposure to elastic ultrasonic vibrations on regions of defects embracing micro-defects termed as “crack mouth.” They are known as the region of “acoustic activity,” method of Acoustic Emission (AE) method. It was established that the high phase-modulation coefficient of reflected field generates intentional Doppler radar signal with the following parameters: amplitude-1-5 nm, 6-30 dB adjusted to 70- 180 mm. This phenomenon is termed as “Gorbunov effect,” which is applied as a remote non-destructive testing method replacing ultrasonic flaw detection and acoustic emission methods.

Novel types of surface acoustic wave microreflectors - Performance analysis and simulations

NASA Astrophysics Data System (ADS)

Golan, G.; Griffel, G.; Seidman, A.; Croitoru, N.

1990-06-01

Surface acoustic waves for micrograting reflectors have been characterized. Based on the perturbation theory, eight different types of structures on an acoustic waveguide were analyzed. Results of simulations of all eight types of corrugation structures were evaluated in order to find the least leaky waveguide, the most efficient reflector (with minimum necessary perturbations), and the optimal mode shape for improved performances. General design curves are presented in order to illustrate the behavior of the incident and reflected waves under a variety of structural conditions. Analytic expressions for the calculations of the mode amplitude and mode shape, and for general acoustic corrugations are derived and then the simulations results are presented.

Analysis of Particle Image Velocimetry (PIV) Data for Acoustic Velocity Measurements

NASA Technical Reports Server (NTRS)

Blackshire, James L.

1997-01-01

Acoustic velocity measurements were taken using Particle Image Velocimetry (PIV) in a Normal Incidence Tube configuration at various frequency, phase, and amplitude levels. This report presents the results of the PIV analysis and data reduction portions of the test and details the processing that was done. Estimates of lower measurement sensitivity levels were determined based on PIV image quality, correlation, and noise level parameters used in the test. Comparison of measurements with linear acoustic theory are presented. The onset of nonlinear, harmonic frequency acoustic levels were also studied for various decibel and frequency levels ranging from 90 to 132 dB and 500 to 3000 Hz, respectively.

The efficiency of simultaneous binaural ocular vestibular evoked myogenic potentials: a comparative study with monaural acoustic stimulation in healthy subjects.

PubMed

Kim, Min-Beom; Ban, Jae Ho

2012-12-01

To evaluate the test-retest reliability and convenience of simultaneous binaural acoustic-evoked ocular vestibular evoked myogenic potentials (oVEMP). Thirteen healthy subjects with no history of ear diseases participated in this study. All subjects underwent oVEMP test with both separated monaural acoustic stimulation and simultaneous binaural acoustic stimulation. For evaluating test-retest reliability, three repetitive sessions were performed in each ear for calculating the intraclass correlation coefficient (ICC) for both monaural and binaural tests. We analyzed data from the biphasic n1-p1 complex, such as latency of peak, inter-peak amplitude, and asymmetric ratio of amplitude in both ears. Finally, we checked the total time required to complete each test for evaluating test convenience. No significant difference was observed in amplitude and asymmetric ratio in comparison between monaural and binaural oVEMP. However, latency was slightly delayed in binaural oVEMP. In test-retest reliability analysis, binaural oVEMP showed excellent ICC values ranging from 0.68 to 0.98 in latency, asymmetric ratio, and inter-peak amplitude. Additionally, the test time was shorter in binaural than monaural oVEMP. oVEMP elicited from binaural acoustic stimulation yields similar satisfactory results as monaural stimulation. Further, excellent test-retest reliability and shorter test time were achieved in binaural than in monaural oVEMP.

Impact of Hypoxia on Startle Response (C-start) of Fish in a Tropical Urban Estuary

NASA Astrophysics Data System (ADS)

Sánchez-García, M.; Zottoli, S. J.; Roberson, L.

2016-02-01

Hypoxic zones have become more prevalent in marine ecosystems as a result of physical changes to the coastal zone, pollution and eutrophication, and are expected to increase in prevalence with climate change. While some studies have examined the behavioral effects of hypoxia on coastal fishes in temperate and sub-tropical zones, none have focused on tropical coastal zones. Behavioral changes may affect fish survival, predator-prey interactions and ultimately ecosystem structure. Through behavioral endpoints we evaluated the effects of non-lethal levels of hypoxia on estuarine fish collected from the tropical Condado Lagoon, San Juan P.R, in a laboratory setting. Two groups of 10 fishes were placed individually in a sound test chamber and oxygen concentrations were modulated from a pre-treatment at 100% oxygen to increasing levels of hypoxia (80, 70, & 60%), followed by a reversal treatment (100%) to test for recovery of pretreatment behavior. An abrupt sound stimulus was used to elicit a startle response, a quantifiable biological endpoint, while recording with a high speed camera. This approach can lend valuable insight into changes in the central nervous system and effects of anthropogenic inputs on tropical ecosystems at the individual- and population-level. We found that hypoxic conditions significantly decrease fish responsiveness; fish startled only half the time at 80% O2 and dropped as much as 61% at 60% O2. Additionally, responsiveness in reversal tests were significantly lower than under pre-treatment conditions. These results indicate that hypoxia may have long-term or possibly permanent effects, even under relatively mild hypoxia conditions common to tropical estuaries. Future work will aim to understand if the startle response can be regained after a hypoxic event.

Tsunami mitigation by resonant triad interaction with acoustic-gravity waves.

PubMed

Kadri, Usama

2017-01-01

Tsunamis have been responsible for the loss of almost a half million lives, widespread long lasting destruction, profound environmental effects, and global financial crisis, within the last two decades. The main tsunami properties that determine the size of impact at the shoreline are its wavelength and amplitude in the ocean. Here, we show that it is in principle possible to reduce the amplitude of a tsunami, and redistribute its energy over a larger space, through forcing it to interact with resonating acoustic-gravity waves. In practice, generating the appropriate acoustic-gravity modes introduces serious challenges due to the high energy required for an effective interaction. However, if the findings are extended to realistic tsunami properties and geometries, we might be able to mitigate tsunamis and so save lives and properties. Moreover, such a mitigation technique would allow for the harnessing of the tsunami's energy.

Tunable damper for an acoustic wave guide

DOEpatents

Rogers, Samuel C.

1984-01-01

A damper for tunably damping acoustic waves in an ultrasonic waveguide is provided which may be used in a hostile environment such as a nuclear reactor. The area of the waveguide, which may be a selected size metal rod in which acoustic waves are to be damped, is wrapped, or surrounded, by a mass of stainless steel wool. The wool wrapped portion is then sandwiched between tuning plates, which may also be stainless steel, by means of clamping screws which may be adjusted to change the clamping force of the sandwiched assembly along the waveguide section. The plates are preformed along their length in a sinusoidally bent pattern with a period approximately equal to the acoustic wavelength which is to be damped. The bent pattern of the opposing plates are in phase along their length relative to their sinusoidal patterns so that as the clamping screws are tightened a bending stress is applied to the waveguide at 180.degree. intervals along the damping section to oppose the acoustic wave motions in the waveguide and provide good coupling of the wool to the guide. The damper is tuned by selectively tightening the clamping screws while monitoring the amplitude of the acoustic waves launched in the waveguide. It may be selectively tuned to damp particular acoustic wave modes (torsional or extensional, for example) and/or frequencies while allowing others to pass unattenuated.

Tunable damper for an acoustic wave guide

DOEpatents

Rogers, S.C.

1982-10-21

A damper for tunably damping acoustic waves in an ultrasonic waveguide is provided which may be used in a hostile environment such as a nuclear reactor. The area of the waveguide, which may be a selected size metal rod in which acoustic waves are to be damped, is wrapped, or surrounded, by a mass of stainless steel wool. The wool wrapped portion is then sandwiched between tuning plates, which may also be stainless steel, by means of clamping screws which may be adjusted to change the clamping force of the sandwiched assembly along the waveguide section. The plates are preformed along their length in a sinusoidally bent pattern with a period approximately equal to the acoustic wavelength which is to be damped. The bent pattern of the opposing plates are in phase along their length relative to their sinusoidal patterns so that as the clamping screws are tightened a bending stress is applied to the waveguide at 180/sup 0/ intervals along the damping section to oppose the acoustic wave motions in the waveguide and provide good coupling of the wool to the guide. The damper is tuned by selectively tightening the clamping screws while monitoring the amplitude of the acoustic waves launched in the waveguide. It may be selectively tuned to damp particular acoustic wave modes (torsional or extensional, for example) and/or frequencies while allowing others to pass unattenuated.

In the Blink of an Eye: Investigating the Role of Awareness in Fear Responding by Measuring the Latency of Startle Potentiation

PubMed Central

Åsli, Ole; Flaten, Magne A.

2012-01-01

The latency of startle reflex potentiation may shed light on the aware and unaware processes underlying associative learning, especially associative fear learning. We review research suggesting that single-cue delay classical conditioning is independent of awareness of the contingency between the conditioned stimulus (CS) and the unconditioned stimulus (US). Moreover, we discuss research that argues that conditioning independent of awareness has not been proven. Subsequently, three studies from our lab are presented that have investigated the role of awareness in classical conditioning, by measuring the minimum latency from CS onset to observed changes in reflexive behavior. In sum, research using this method shows that startle is potentiated 30 to 100 ms after CS onset following delay conditioning. Following trace fear conditioning, startle is potentiated 1500 ms after CS presentation. These results indicate that the process underlying delay conditioned responding is independent of awareness, and that trace fear conditioned responding is dependent on awareness. Finally, this method of investigating the role of awareness is discussed and future research possibilities are proposed. PMID:24962686

Investigating acoustic-induced deformations in a foam using multiple light scattering.

PubMed

Erpelding, M; Guillermic, R M; Dollet, B; Saint-Jalmes, A; Crassous, J

2010-08-01

We have studied the effect of an external acoustic wave on bubble displacements inside an aqueous foam. The signature of the acoustic-induced bubble displacements is found using a multiple light scattering technique, and occurs as a modulation on the photon correlation curve. Measurements for various sound frequencies and amplitudes are compared to analytical predictions and numerical simulations. These comparisons finally allow us to elucidate the nontrivial acoustic displacement profile inside the foam; in particular, we find that the acoustic wave creates a localized shear in the vicinity of the solid walls holding the foam, as a consequence of inertial contributions. This study of how bubbles "dance" inside a foam as a response to sound turns out to provide new insights on foam acoustics and sound transmission into a foam, foam deformation at high frequencies, and analysis of light scattering data in samples undergoing nonhomogeneous deformations.

Different effects of isolation-rearing and neonatal MK-801 treatment on attentional modulations of prepulse inhibition of startle in rats.

PubMed

Wu, Zhe-Meng; Ding, Yu; Jia, Hong-Xiao; Li, Liang

2016-09-01

Prepulse inhibition (PPI) is suppression of the startle reflex by a weaker sensory stimulus (prepulse) preceding the startling stimulus. In people with schizophrenia, impairment of attentional modulation of PPI, but not impairment of baseline PPI, is correlated with symptom severity. In rats, both fear conditioning of prepulse and perceptually spatial separation between the conditioned prepulse and a noise masker enhance PPI (the paradigms of attentional modulation of PPI). As a neurodevelopmental model of schizophrenia, isolation rearing impairs both baseline PPI and attentional modulations of PPI in rats. This study examined in Sprague-Dawley male rats whether neonatally blocking N-methyl-D-aspartate (NMDA) receptors specifically affects attentional modulations of PPI during adulthood. Both socially reared rats with neonatal exposure to the NMDA receptor antagonist MK-801 and isolation-reared rats exhibited augmented startle responses, but only isolation rearing impaired baseline PPI. Fear conditioning of the prepulse enhanced PPI in socially reared rats, but MK-801-treated rats lost the prepulse feature specificity. Perceptually spatial separation between the conditioned prepulse and a noise masker further enhanced PPI only in normally reared rats. Clozapine administration during adulthood generally weakened startle, enhanced baseline PPI in neonatally interrupted rats, and restored the fear conditioning-induced PPI enhancement in isolation-reared rats with a loss of the prepulse feature specificity. Clozapine administration also abolished both the perceptual separation-induced PPI enhancement in normally reared rats and the fear conditioning-induced PPI enhancement in MK-801-treated rats. Isolation rearing impairs both baseline PPI and attentional modulations of PPI, but neonatally disrupting NMDA receptor-mediated transmissions specifically impair attentional modulations of PPI. Clozapine has limited alleviating effects.

Fear-Potential Startle as a Model System for Analyzing Learning and Memory

DTIC Science & Technology

1988-09-21

connection between the central nucleus of the amygdala and the nucleus reticularis pontis caudalis, an obligatory part of the startle pathway. Because we...Miserendino, M and Davis, M. A direct pathway from the central nucleus of the amygdala to the region of the nucleus reticularis pontis caudalis critical for...blocked by drugs that decrease anxiety in humans as well as by lesions of the central nucleus of the amygdala, an area of the brain known to be critical for

Artificial neural networks for acoustic target recognition

NASA Astrophysics Data System (ADS)

Robertson, James A.; Mossing, John C.; Weber, Bruce A.

1995-04-01

Acoustic sensors can be used to detect, track and identify non-line-of-sight targets passively. Attempts to alter acoustic emissions often result in an undesirable performance degradation. This research project investigates the use of neural networks for differentiating between features extracted from the acoustic signatures of sources. Acoustic data were filtered and digitized using a commercially available analog-digital convertor. The digital data was transformed to the frequency domain for additional processing using the FFT. Narrowband peak detection algorithms were incorporated to select peaks above a user defined SNR. These peaks were then used to generate a set of robust features which relate specifically to target components in varying background conditions. The features were then used as input into a backpropagation neural network. A K-means unsupervised clustering algorithm was used to determine the natural clustering of the observations. Comparisons between a feature set consisting of the normalized amplitudes of the first 250 frequency bins of the power spectrum and a set of 11 harmonically related features were made. Initial results indicate that even though some different target types had a tendency to group in the same clusters, the neural network was able to differentiate the targets. Successful identification of acoustic sources under varying operational conditions with high confidence levels was achieved.

Acoustic response of Helmholtz dampers in the presence of hot grazing flow

NASA Astrophysics Data System (ADS)

Ćosić, B.; Wassmer, D.; Terhaar, S.; Paschereit, C. O.

2015-01-01

Thermoacoustic instabilities are high amplitude instabilities of premixed gas turbine combustors. Cooled passive dampers are used to attenuate or suppress these instabilities in the combustion chamber. For the first time, the influence of temperature differences between the grazing flow in the combustor and the cross-flow emanating from the Helmholtz damper is comprehensively investigated in the linear and nonlinear amplitude regime. The flow field inside the resonator and in the vicinity of the neck is measured with high-speed particle image velocimetry for various amplitudes and at different momentum-flux ratios of grazing and purging flow. Seeding is used as a tracer to qualitatively assess the mixing of the grazing and purging flow as well as the ingestion into the neck of the resonator. Experimentally, the acoustic response for various temperature differences between grazing and purging flow is investigated. The multi-microphone method, in combination with two microphones flush-mounted in the resonator volume and two microphones in the plane of the resonator entrance, is used to determine the impedance of the Helmholtz resonator in the linear and nonlinear amplitude regime for various temperatures and different momentum-flux ratios. Additionally, a thermocouple was used to measure the temperature in the neck. The acoustic response and the temperature measurements are used to obtain the virtual neck length and the effective area jump from a detailed impedance model. This model is extended to include the observed acoustic energy dissipation caused by the density gradients at the neck vicinity. A clear correlation between temperature differences and changes of the mass end-correction is confirmed. The capabilities of the impedance model are demonstrated.

Effect of Forcing Function on Nonlinear Acoustic Standing Waves

NASA Technical Reports Server (NTRS)

Finkheiner, Joshua R.; Li, Xiao-Fan; Raman, Ganesh; Daniels, Chris; Steinetz, Bruce

2003-01-01

Nonlinear acoustic standing waves of high amplitude have been demonstrated by utilizing the effects of resonator shape to prevent the pressure waves from entering saturation. Experimentally, nonlinear acoustic standing waves have been generated by shaking an entire resonating cavity. While this promotes more efficient energy transfer than a piston-driven resonator, it also introduces complicated structural dynamics into the system. Experiments have shown that these dynamics result in resonator forcing functions comprised of a sum of several Fourier modes. However, previous numerical studies of the acoustics generated within the resonator assumed simple sinusoidal waves as the driving force. Using a previously developed numerical code, this paper demonstrates the effects of using a forcing function constructed with a series of harmonic sinusoidal waves on resonating cavities. From these results, a method will be demonstrated which allows the direct numerical analysis of experimentally generated nonlinear acoustic waves in resonators driven by harmonic forcing functions.

Acoustic measurement study 40 by 80 foot subsonic wind tunnel

NASA Technical Reports Server (NTRS)

1974-01-01

An acoustical study conducted during the period from September 1, 1973 to April 30, 1974 measured sound pressure levels and vibration amplitudes inside and outside of the subsonic tunnel and on the tunnel structure. A discussion of the technical aspects of the study, the field measurement and data reduction procedures, and results are presentd, and conclusions resulting from the study which bear upon near field and far field tunnel noise, upon the tunnel as an acoustical enclosure, and upon the sources of noise within the tunnel drive system are given.

Non-dimensional groups in the description of finite-amplitude sound propagation through aerosols

NASA Technical Reports Server (NTRS)

Scott, D. S.

1976-01-01

Several parameters, which have fairly transparent physical interpretations, appear in the analytic description of finite-amplitude sound propagation through aerosols. Typically, each of these parameters characterizes, in some sense, either the sound or the aerosol. It also turns out that fairly obvious combinations of these parameters yield non-dimensional groups which, in turn, characterize the nature of the acoustic-aerosol interaction. This theme is developed in order to illustrate how a quick examination of such parameters and groups can yield information about the nature of the processes involved, without the necessity of extensive mathematical analysis. This concept is developed primarily from the viewpoint of sound propagation through aerosols, although complimentary acoustic-aerosol interaction phenomena are briefly noted.

Nonlinear ultrasound imaging of nanoscale acoustic biomolecules

NASA Astrophysics Data System (ADS)

Maresca, David; Lakshmanan, Anupama; Lee-Gosselin, Audrey; Melis, Johan M.; Ni, Yu-Li; Bourdeau, Raymond W.; Kochmann, Dennis M.; Shapiro, Mikhail G.

2017-02-01

Ultrasound imaging is widely used to probe the mechanical structure of tissues and visualize blood flow. However, the ability of ultrasound to observe specific molecular and cellular signals is limited. Recently, a unique class of gas-filled protein nanostructures called gas vesicles (GVs) was introduced as nanoscale (˜250 nm) contrast agents for ultrasound, accompanied by the possibilities of genetic engineering, imaging of targets outside the vasculature and monitoring of cellular signals such as gene expression. These possibilities would be aided by methods to discriminate GV-generated ultrasound signals from anatomical background. Here, we show that the nonlinear response of engineered GVs to acoustic pressure enables selective imaging of these nanostructures using a tailored amplitude modulation strategy. Finite element modeling predicted a strongly nonlinear mechanical deformation and acoustic response to ultrasound in engineered GVs. This response was confirmed with ultrasound measurements in the range of 10 to 25 MHz. An amplitude modulation pulse sequence based on this nonlinear response allows engineered GVs to be distinguished from linear scatterers and other GV types with a contrast ratio greater than 11.5 dB. We demonstrate the effectiveness of this nonlinear imaging strategy in vitro, in cellulo, and in vivo.

Pre-pubertal stress exposure affects adult behavioral response in association with changes in circulating corticosterone and brain-derived neurotrophic factor.

PubMed

Bazak, Noam; Kozlovsky, Nitsan; Kaplan, Zeev; Matar, Michael; Golan, Hava; Zohar, Joseph; Richter-Levin, Gal; Cohen, Hagit

2009-07-01

Early-life stress produces a cascade of neurobiological events that cause enduring changes in neural plasticity and synaptic efficacy that appear to play pivotal roles in the pathophysiology of post-traumatic stress disorder (PTSD). Brain-derived neurotrophic factor (BDNF) has been implicated in the neurobiological mechanisms of these changes, in interaction with components of the stress response, such as corticosterone. This study examined the consequences of juvenile stress for behavior during adulthood in association with circulating corticosterone levels and BDNF expression. The experiments examined single exposure to predator scent stress (soiled cat litter for 10 min) as compared to repeated exposure, early in life and later on. Behavioral responses were assessed in the elevated plus maze and the acoustic startle response paradigms at 28, 60 and 90 days of age. Plasma corticosterone was measured and brain areas analyzed for BDNF levels. The results show that juvenile stress exposure increased anxiety-like behavior and startle amplitude and decreased plasma corticosterone. This response was seen immediately after exposure and also long term. Adult stress exposure increased anxiety-like behavior, startle amplitude and plasma corticosterone. Exposure to both early and later life trauma elicited reduced levels of corticosterone following the initial exposure, which were not raised by re-exposure, and elicited significant downregulation of BDNF mRNA and protein levels in the hippocampus CA1 subregion. The consequences of adult stress exposure were more severe in rats were exposed to the same stressor as juveniles, indicated increased vulnerability. The results suggest that juvenile stress has resounding effects in adulthood reflected in behavioral responses. The concomitant changes in BDNF and corticosterone levels may mediate the changes in neural plasticity and synaptic functioning underlying clinical manifestations of PTSD.

Effect of "enriched environment" during development on adult rat behavior and response to the dopamine receptor agonist apomorphine.

PubMed

Hoffmann, L C; Schütte, S R M; Koch, M; Schwabe, K

2009-02-18

Enriched housing conditions (enriched environment, EE) during development has been shown to influence adult rat behavior and transmitter systems, especially dopamine function. We were interested in how different degrees of enrichment during development would affect adult rats' behavior and response to dopamine receptor challenge. Two groups of male Wistar rats (n=11-12) were raised under two different degrees of EE, i.e. "high enriched" and "low enriched" groups. A third group was kept under standard conditions and served as "non-enriched" control. As adults, rats were tested for anxiety (elevated plus-maze), for spatial learning (four-arm-baited eight-arm radial maze), and for motivation (breakpoint of the progressive ratio test). Finally, locomotor activity (activity box) and sensorimotor gating (prepulse inhibition (PPI) of the acoustic startle response (ASR)) were tested with and without challenge with the dopamine receptor agonist apomorphine. The time spent on the open or enclosed arms of the elevated plus-maze did not differ between groups, but the high enriched group showed higher rearing activity on the open arms. The breakpoint did not differ between groups. Learning and memory in the radial maze task only differed on the first few trials, but high enriched rats run faster compared with the other groups. In contrast, in the activity box enriched groups were less active, but apomorphine had the highest effect. Between groups, no difference in PPI and startle amplitude was found, but in the high and low EE group startle amplitude was enhanced after administration of apomorphine, while the PPI deficit induced by this drug was not different between groups. Altogether, we found no evidence that different amounts of environmental enrichment without differences in social EE affect rats' cognitive, emotional or motivational behavior. However, motor activity seems to be enhanced when rats are behaviorally or pharmacologically challenged by dopamine receptor

Association between violent behaviour and impaired prepulse inhibition of the startle response in antisocial personality disorder and schizophrenia.

PubMed

Kumari, Veena; Das, Mrigen; Hodgins, Sheilagh; Zachariah, Elizabeth; Barkataki, Ian; Howlett, Michael; Sharma, Tonmoy

2005-03-07

Violent behaviour has a strong association with antisocial personality disorder (APD) and schizophrenia. Although developments in the understanding of socio-environmental factors associated with violence should not be ignored, advances in prevention and treatment of violent behaviour would benefit by improved understanding of its neurobiological and cognitive basis. The authors, therefore, investigated prepulse inhibition (PPI) of the startle response in APD and schizophrenia in relation to a history of serious violence. The neural substrates of PPI, especially the hippocampus, amygdala, thalamus and basal ganglia, are implicated in violence as well as in APD and schizophrenia. The study included four groups: (i) patients with APD and a history of violence, (ii) patients with schizophrenia and a history of violence, (iii) patients with schizophrenia without a history of violence, and (iv) healthy subjects with no history of violence or a mental disorder. All subjects were assessed identically on acoustic PPI. Compared to healthy subjects, significantly reduced PPI occurred in APD, violent schizophrenia and non-violent schizophrenia patients. Although PPI did not significantly differentiate the three clinical groups, high ratings of violence were modestly associated with reduced PPI across the entire study sample. Violent patients with impulsive and premeditated violence showed comparable PPI. The association between violent behaviour and impaired PPI suggests that neural structures and functions underlying PPI are implicated in (inhibition of) violence.

Interdependent effects of sound duration and amplitude on neuronal onset response in mice inferior colliculus.

PubMed

Wang, Ningqian; Wang, Xiao; Yang, Xiaoli; Tang, Jie; Xiao, Zhongju

2014-01-16

In this study, we adopted iso-frequency pure tone bursts to investigate the interdependent effects of sound amplitude/intensity and duration on mice inferior colliculus (IC) neuronal onset responses. On the majority of the sampled neurons (n=57, 89.1%), sound amplitude and duration had effects on the neuronal response to each other by showing complex changes of the rat-intensity function/duration selectivity types and/or best amplitudes (BAs)/durations (BDs), evaluated by spike counts. These results suggested that the balance between the excitatory and inhibitory inputs set by one acoustic parameter, amplitude or duration, affected the neuronal spike counts responses to the other. Neuronal duration selectivity types were altered easily by the low-amplitude sounds while the changes of rate-intensity function types had no obvious preferred stimulus durations. However, the first spike latencies (FSLs) of the onset response neurons were relative stable to iso-amplitude sound durations and changing systematically along with the sound levels. The superimposition of FSL and duration threshold (DT) as a function of stimulus amplitude after normalization indicated that the effects of the sound levels on FSLs are considered on DT actually. © 2013 Published by Elsevier B.V.

Measurement of acoustic velocity components in a turbulent flow using LDV and high-repetition rate PIV

NASA Astrophysics Data System (ADS)

Léon, Olivier; Piot, Estelle; Sebbane, Delphine; Simon, Frank

2017-06-01

The present study provides theoretical details and experimental validation results to the approach proposed by Minotti et al. (Aerosp Sci Technol 12(5):398-407, 2008) for measuring amplitudes and phases of acoustic velocity components (AVC) that are waveform parameters of each component of velocity induced by an acoustic wave, in fully turbulent duct flows carrying multi-tone acoustic waves. Theoretical results support that the turbulence rejection method proposed, based on the estimation of cross power spectra between velocity measurements and a reference signal such as a wall pressure measurement, provides asymptotically efficient estimators with respect to the number of samples. Furthermore, it is shown that the estimator uncertainties can be simply estimated, accounting for the characteristics of the measured flow turbulence spectra. Two laser-based measurement campaigns were conducted in order to validate the acoustic velocity estimation approach and the uncertainty estimates derived. While in previous studies estimates were obtained using laser Doppler velocimetry (LDV), it is demonstrated that high-repetition rate particle image velocimetry (PIV) can also be successfully employed. The two measurement techniques provide very similar acoustic velocity amplitude and phase estimates for the cases investigated, that are of practical interest for acoustic liner studies. In a broader sense, this approach may be beneficial for non-intrusive sound emission studies in wind tunnel testings.

Altered cerebellar development in nuclear receptor TAK1/ TR4 null mice is associated with deficits in GLAST(+) glia, alterations in social behavior, motor learning, startle reactivity, and microglia.

PubMed

Kim, Yong-Sik; Harry, G Jean; Kang, Hong Soon; Goulding, David; Wine, Rob N; Kissling, Grace E; Liao, Grace; Jetten, Anton M

2010-09-01

Previously, deficiency in the expression of the nuclear orphan receptor TAK1 was found to be associated with delayed cerebellar granule cell migration and Purkinje cell maturation with a permanent deficit in foliation of lobules VI–VII, suggesting a role for TAK1 in cerebellum development. In this study, we confirm that TAK1-deficient (TAK1(−/−)) mice have a smaller cerebellum and exhibit a disruption of lobules VI–VII. We extended these studies and show that at postnatal day 7, TAK1(−/−) mice exhibit a delay in monolayer maturation of dysmorphic calbindin 28K-positive Purkinje cells. The astrocyte-specific glutamate transporter (GLAST) was expressed within Bergmann fibers and internal granule cell layer at significantly lower levels in the cerebellum of TAK1(−/−) mice. At PND21, Golgi-positive Purkinje cells in TAK1(−/−) mice displayed a smaller soma (18%) and shorter distance to first branch point (35%). Neuronal death was not observed in TAK1(−/−) mice at PND21; however, activated microglia were present in the cerebellum, suggestive of earlier cell death. These structural deficits in the cerebellum were not sufficient to alter motor strength, coordination, or activity levels; however, deficits in acoustic startle response, prepulse startle inhibition, and social interactions were observed. Reactions to a novel environment were inhibited in a light/dark chamber, open-field, and home-cage running wheel. TAK1(−/−) mice displayed a plateau in performance on the running wheel, suggesting a deficit in learning to coordinate performance on a motor task. These data indicate that TAK1 is an important transcriptional modulator of cerebellar development and neurodevelopmentally regulated behavior.

The effects of external acoustic pressure fields on a free-running supercavitating projectile.

PubMed

Cameron, Peter J K; Rogers, Peter H; Doane, John W

2010-12-01

Proliferation of supercavitating torpedoes has motivated research on countermeasures against them as well as on the fluid phenomenon which makes them possible. The goal of this research was to investigate an envisaged countermeasure, an acoustic field capable of slowing or diverting the weapon by disrupting the cavitation envelope. The research focused on the interactions between high pressure amplitude sound waves and a supercavity produced by a small free-flying projectile. The flight dynamics and cavity geometry measurements were compared to control experiments and theoretical considerations were made for evaluating the effects. Corrugations on the cavity/water interface caused by the pressure signal have been observed and characterized. Results also show that the accuracy of a supercavitating projectile can be adversely affected by the sound signal. This research concludes with results that indicate that it is acoustic cavitation in the medium surrounding the supercavity, caused by the high pressure amplitude sound, that is responsible for the reduced accuracy. A hypothesis has been presented addressing the means by which the acoustic cavitation could cause this effect.