The CCN Executive Committee invites you to a lecture by Dr. George Koob!

The Center for Clinical and Cognitive Neuroscience Executive Committee is pleased to announce the CCN Distinguished Speaker Series. The goal of this speaker series is to invite high profile speakers to the SDSU campus to provide both public lectures and lectures that highlight new discoveries and cutting-edge research in cognitive neuroscience.

---

Up Next – Dr. George Koob!

The CCN Executive Committee invites you to a lecture by Dr. George Koob!

Dr. George Koob

“Neurobiology of addiction: A stress surfeit disorder” Dr. George Koob Director of the National Institute of Alcohol Abuse and Alcoholism Friday, April 22, 2016 1-2:30pm, Conrad Prebys Aztec Center Theatre 2:30-3:30pm, Light reception to follow on the 4th Floor Outdoor Terrace Paid parking available in PS6 (pdf)

Abstract:

Addiction to alcohol and drugs has been conceptualized as a chronically relapsing disorder of compulsive drug seeking and taking that progresses through three stages: binge/intoxication, withdrawal/negative affect, and preoccupation/anticipation. Multiple sources of reinforcement contribute to the motivation to compulsively seek drugs including core elements of positive reinforcement (binge/intoxication stage) and negative reinforcement (withdrawal/negative affect stage) and conditioned reinforcement (preoccupation-anticipation stage). The construct of negative reinforcement can be defined here as drug taking that alleviates a negative emotional state created by drug abstinence. The negative emotional state that drives such negative reinforcement is hypothesized to derive from dysregulation of key neurochemical circuits that form the brain stress systems within the extended amygdala, basal ganglia and frontal cortex. Specific neuroplasticity in these circuits includes not only recruitment of the classic hormonal stress axis mediated by corticotropin-releasing factor (CRF) in the hypothalamus, but also extrahypothalamic CRF in the extended amygdala and frontal cortex. Recruitment of dynorphin-k opioid aversive systems in the ventral striatum and extended amygdala represents another dynamic neuroplasticity of the brain stress systems. In animal models, acute withdrawal from all major drugs of abuse increases reward thresholds, increases anxiety-like responses, increases extracellular levels of CRF in the central nucleus of the amygdala and increases basal ganglia dynorphin. CRF and kappa receptor antagonists block motivational responses associated with withdrawal, and compulsive-like drug taking during extended access. Excessive drug taking also engages activation of CRF in the medial prefrontal cortex and is accompanied by deficits in executive function that may facilitate the transition to compulsive-like responding and relapse. Thus, compelling evidence exists to argue that plasticity in the brain stress systems, a heretofore largely neglected component of dependence and addiction, is triggered by acute excessive drug intake, is sensitized during repeated withdrawal, persists into protracted abstinence, and contributes to the development and persistence of addiction. The neuroplasticity of the brain stress systems in addiction not only provides understanding of the neurobiology of negative reinforcement mechanisms in addiction, but also provides key insights into how the brain processes negative emotions.

 

 

 

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The CCN Executive Committee invites you to a lecture by Dr. George Koob!

The Center for Clinical and Cognitive Neuroscience Executive Committee is pleased to announce the CCN Distinguished Speaker Series. The goal of this speaker series is to invite high profile speakers to the SDSU campus to provide both public lectures and lectures that highlight new discoveries and cutting-edge research in cognitive neuroscience.

---

Up Next – Dr. George Koob!

The CCN Executive Committee invites you to a lecture by Dr. George Koob!

Dr. George Koob

“Neurobiology of addiction: A stress surfeit disorder” Dr. George Koob Director of the National Institute of Alcohol Abuse and Alcoholism Friday, April 22, 2016 1-2:30pm, Conrad Prebys Aztec Center Theatre 2:30-3:30pm, Light reception to follow on the 4th Floor Outdoor Terrace Paid parking available in PS6 (pdf)

Abstract:

Addiction to alcohol and drugs has been conceptualized as a chronically relapsing disorder of compulsive drug seeking and taking that progresses through three stages: binge/intoxication, withdrawal/negative affect, and preoccupation/anticipation. Multiple sources of reinforcement contribute to the motivation to compulsively seek drugs including core elements of positive reinforcement (binge/intoxication stage) and negative reinforcement (withdrawal/negative affect stage) and conditioned reinforcement (preoccupation-anticipation stage). The construct of negative reinforcement can be defined here as drug taking that alleviates a negative emotional state created by drug abstinence. The negative emotional state that drives such negative reinforcement is hypothesized to derive from dysregulation of key neurochemical circuits that form the brain stress systems within the extended amygdala, basal ganglia and frontal cortex. Specific neuroplasticity in these circuits includes not only recruitment of the classic hormonal stress axis mediated by corticotropin-releasing factor (CRF) in the hypothalamus, but also extrahypothalamic CRF in the extended amygdala and frontal cortex. Recruitment of dynorphin-k opioid aversive systems in the ventral striatum and extended amygdala represents another dynamic neuroplasticity of the brain stress systems. In animal models, acute withdrawal from all major drugs of abuse increases reward thresholds, increases anxiety-like responses, increases extracellular levels of CRF in the central nucleus of the amygdala and increases basal ganglia dynorphin. CRF and kappa receptor antagonists block motivational responses associated with withdrawal, and compulsive-like drug taking during extended access. Excessive drug taking also engages activation of CRF in the medial prefrontal cortex and is accompanied by deficits in executive function that may facilitate the transition to compulsive-like responding and relapse. Thus, compelling evidence exists to argue that plasticity in the brain stress systems, a heretofore largely neglected component of dependence and addiction, is triggered by acute excessive drug intake, is sensitized during repeated withdrawal, persists into protracted abstinence, and contributes to the development and persistence of addiction. The neuroplasticity of the brain stress systems in addiction not only provides understanding of the neurobiology of negative reinforcement mechanisms in addiction, but also provides key insights into how the brain processes negative emotions.

 

 

 

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The CCN Executive Committee invites you to a lecture by Dr. George Koob!

The Center for Clinical and Cognitive Neuroscience Executive Committee is pleased to announce the CCN Distinguished Speaker Series. The goal of this speaker series is to invite high profile speakers to the SDSU campus to provide both public lectures and lectures that highlight new discoveries and cutting-edge research in cognitive neuroscience.

---

Up Next – Dr. George Koob!

The CCN Executive Committee invites you to a lecture by Dr. George Koob!

Dr. George Koob

“Neurobiology of addiction: A stress surfeit disorder” Dr. George Koob Director of the National Institute of Alcohol Abuse and Alcoholism Friday, April 22, 2016 1-2:30pm, Conrad Prebys Aztec Center Theatre 2:30-3:30pm, Light reception to follow on the 4th Floor Outdoor Terrace Paid parking available in PS6 (pdf)

Abstract:

Addiction to alcohol and drugs has been conceptualized as a chronically relapsing disorder of compulsive drug seeking and taking that progresses through three stages: binge/intoxication, withdrawal/negative affect, and preoccupation/anticipation. Multiple sources of reinforcement contribute to the motivation to compulsively seek drugs including core elements of positive reinforcement (binge/intoxication stage) and negative reinforcement (withdrawal/negative affect stage) and conditioned reinforcement (preoccupation-anticipation stage). The construct of negative reinforcement can be defined here as drug taking that alleviates a negative emotional state created by drug abstinence. The negative emotional state that drives such negative reinforcement is hypothesized to derive from dysregulation of key neurochemical circuits that form the brain stress systems within the extended amygdala, basal ganglia and frontal cortex. Specific neuroplasticity in these circuits includes not only recruitment of the classic hormonal stress axis mediated by corticotropin-releasing factor (CRF) in the hypothalamus, but also extrahypothalamic CRF in the extended amygdala and frontal cortex. Recruitment of dynorphin-k opioid aversive systems in the ventral striatum and extended amygdala represents another dynamic neuroplasticity of the brain stress systems. In animal models, acute withdrawal from all major drugs of abuse increases reward thresholds, increases anxiety-like responses, increases extracellular levels of CRF in the central nucleus of the amygdala and increases basal ganglia dynorphin. CRF and kappa receptor antagonists block motivational responses associated with withdrawal, and compulsive-like drug taking during extended access. Excessive drug taking also engages activation of CRF in the medial prefrontal cortex and is accompanied by deficits in executive function that may facilitate the transition to compulsive-like responding and relapse. Thus, compelling evidence exists to argue that plasticity in the brain stress systems, a heretofore largely neglected component of dependence and addiction, is triggered by acute excessive drug intake, is sensitized during repeated withdrawal, persists into protracted abstinence, and contributes to the development and persistence of addiction. The neuroplasticity of the brain stress systems in addiction not only provides understanding of the neurobiology of negative reinforcement mechanisms in addiction, but also provides key insights into how the brain processes negative emotions.

 

 

 

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Effect of Gait Retraining for Reducing Ambulatory Knee Load on Trunk Biomechanics and Trunk Muscle Activity

Publication date: Available online 4 April 2016
Source:Gait & Posture
Author(s): Corina Nüesch, Dominik Laffer, Cordula Netzer, Geert Pagenstert, Annegret Mündermann
The purpose of this study was to test the hypothesis that walking with increased medio-lateral trunk sway is associated with lower external knee adduction moment and lower extremity muscle activation, and higher external ipsilateral trunk moment and trunk muscle activity than walking with normal trunk sway in healthy participants. Fifteen participants performed walking trials with normal and increased medio-lateral trunk sway. Maximum trunk sway, first maximum knee adduction moment, lateral trunk bending moment, and bilateral vastus medialis, vastus lateralis, gluteus medius, rectus abdominis, external oblique and erector spinae muscle activity were computed. Walking with increased trunk sway was associated with lower maximum knee adduction moment (95% confidence interval (CI): 0.50 to 0.62 Nm/kg vs. 0.62 to 0.76 Nm/kg; P<.001) and ipsilateral gluteus medius (-17%; P=.014) and erector spinae muscle activity (-24%; P=.004) and greater maximum lateral trunk bending moment (+34%; P<.001) and contralateral external oblique muscle activity (+60%; P=.009). In all participants, maximum knee adduction moment was negatively correlated and maximum trunk moment was positively correlated with maximum trunk sway. The results of this study suggest that walking with increased trunk sway not only reduces the external knee adduction moment but also alters and possibly increases the load on the trunk. Hence, load-altering biomechanical interventions should always be evaluated not only regarding their effects on the index joint but on other load-bearing joints such as the spine.



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Effect of Gait Retraining for Reducing Ambulatory Knee Load on Trunk Biomechanics and Trunk Muscle Activity

Publication date: Available online 4 April 2016
Source:Gait & Posture
Author(s): Corina Nüesch, Dominik Laffer, Cordula Netzer, Geert Pagenstert, Annegret Mündermann
The purpose of this study was to test the hypothesis that walking with increased medio-lateral trunk sway is associated with lower external knee adduction moment and lower extremity muscle activation, and higher external ipsilateral trunk moment and trunk muscle activity than walking with normal trunk sway in healthy participants. Fifteen participants performed walking trials with normal and increased medio-lateral trunk sway. Maximum trunk sway, first maximum knee adduction moment, lateral trunk bending moment, and bilateral vastus medialis, vastus lateralis, gluteus medius, rectus abdominis, external oblique and erector spinae muscle activity were computed. Walking with increased trunk sway was associated with lower maximum knee adduction moment (95% confidence interval (CI): 0.50 to 0.62 Nm/kg vs. 0.62 to 0.76 Nm/kg; P<.001) and ipsilateral gluteus medius (-17%; P=.014) and erector spinae muscle activity (-24%; P=.004) and greater maximum lateral trunk bending moment (+34%; P<.001) and contralateral external oblique muscle activity (+60%; P=.009). In all participants, maximum knee adduction moment was negatively correlated and maximum trunk moment was positively correlated with maximum trunk sway. The results of this study suggest that walking with increased trunk sway not only reduces the external knee adduction moment but also alters and possibly increases the load on the trunk. Hence, load-altering biomechanical interventions should always be evaluated not only regarding their effects on the index joint but on other load-bearing joints such as the spine.



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Effect of Gait Retraining for Reducing Ambulatory Knee Load on Trunk Biomechanics and Trunk Muscle Activity

Publication date: Available online 4 April 2016
Source:Gait & Posture
Author(s): Corina Nüesch, Dominik Laffer, Cordula Netzer, Geert Pagenstert, Annegret Mündermann
The purpose of this study was to test the hypothesis that walking with increased medio-lateral trunk sway is associated with lower external knee adduction moment and lower extremity muscle activation, and higher external ipsilateral trunk moment and trunk muscle activity than walking with normal trunk sway in healthy participants. Fifteen participants performed walking trials with normal and increased medio-lateral trunk sway. Maximum trunk sway, first maximum knee adduction moment, lateral trunk bending moment, and bilateral vastus medialis, vastus lateralis, gluteus medius, rectus abdominis, external oblique and erector spinae muscle activity were computed. Walking with increased trunk sway was associated with lower maximum knee adduction moment (95% confidence interval (CI): 0.50 to 0.62 Nm/kg vs. 0.62 to 0.76 Nm/kg; P<.001) and ipsilateral gluteus medius (-17%; P=.014) and erector spinae muscle activity (-24%; P=.004) and greater maximum lateral trunk bending moment (+34%; P<.001) and contralateral external oblique muscle activity (+60%; P=.009). In all participants, maximum knee adduction moment was negatively correlated and maximum trunk moment was positively correlated with maximum trunk sway. The results of this study suggest that walking with increased trunk sway not only reduces the external knee adduction moment but also alters and possibly increases the load on the trunk. Hence, load-altering biomechanical interventions should always be evaluated not only regarding their effects on the index joint but on other load-bearing joints such as the spine.



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Multidimensional Approach to the Development of a Mandarin Chinese–Oriented Sound Test

Purpose

Because the Ling six-sound test is based on American English phonemes, it can yield unreliable results when administered to non-English speakers. In this study, we aimed to improve specifically the diagnostic palette for Mandarin Chinese users by developing an adapted version of the Ling six-sound test.

Method

To determine the set of testing sounds, we performed an exhaustive acoustic and statistical analysis in which we considered not only the general acoustic properties but also the order of acquisition and the inter- and intraspeaker variability.

Results

Six phonemes (/u, ə, a, i, tɕ^h, s/) were selected as the testing items for the Mandarin Chinese sound test because these sounds exhibit a highly compartmentalized frequency specificity, spanning the entire Chinese speech spectrum, as well as a relatively low articulatory variability and can be acquired fairly early.

Conclusion

Through adopting language-dependent modifications, caregivers and professionals should have a more adequate tool to monitor children's auditory access to the full range of Mandarin speech sounds.

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Multidimensional Approach to the Development of a Mandarin Chinese–Oriented Sound Test

Purpose

Because the Ling six-sound test is based on American English phonemes, it can yield unreliable results when administered to non-English speakers. In this study, we aimed to improve specifically the diagnostic palette for Mandarin Chinese users by developing an adapted version of the Ling six-sound test.

Method

To determine the set of testing sounds, we performed an exhaustive acoustic and statistical analysis in which we considered not only the general acoustic properties but also the order of acquisition and the inter- and intraspeaker variability.

Results

Six phonemes (/u, ə, a, i, tɕ^h, s/) were selected as the testing items for the Mandarin Chinese sound test because these sounds exhibit a highly compartmentalized frequency specificity, spanning the entire Chinese speech spectrum, as well as a relatively low articulatory variability and can be acquired fairly early.

Conclusion

Through adopting language-dependent modifications, caregivers and professionals should have a more adequate tool to monitor children's auditory access to the full range of Mandarin speech sounds.

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Multidimensional Approach to the Development of a Mandarin Chinese–Oriented Sound Test

Purpose

Because the Ling six-sound test is based on American English phonemes, it can yield unreliable results when administered to non-English speakers. In this study, we aimed to improve specifically the diagnostic palette for Mandarin Chinese users by developing an adapted version of the Ling six-sound test.

Method

To determine the set of testing sounds, we performed an exhaustive acoustic and statistical analysis in which we considered not only the general acoustic properties but also the order of acquisition and the inter- and intraspeaker variability.

Results

Six phonemes (/u, ə, a, i, tɕ^h, s/) were selected as the testing items for the Mandarin Chinese sound test because these sounds exhibit a highly compartmentalized frequency specificity, spanning the entire Chinese speech spectrum, as well as a relatively low articulatory variability and can be acquired fairly early.

Conclusion

Through adopting language-dependent modifications, caregivers and professionals should have a more adequate tool to monitor children's auditory access to the full range of Mandarin speech sounds.

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Exploring the Utility of a School-Age Narrative Microstructure Index: Proportion of Restricted Utterances

Purpose

This research attempted to replicate Hoffman's 2009 finding that the proportion of narrative utterances with semantic or syntactic errors (i.e., ≥ 14% “restricted utterances”) can differentiate school-age children with typical development from those with language impairment with a sensitivity of 83% and specificity of 88%.

Method

Methods similar to Hoffman (2009) were used to evaluate an existing set of narratives from 16 age-matched pairs of 8- to 9-year-old children, half with known language impairment. Transcripts were segmented into T-units; a code of [RESTRICTED] was assigned to any utterance with semantic or syntactic errors.

Results

A Welch's t test for independent samples revealed a statistically significant difference in the mean proportion of restricted utterances between the two groups after accommodation for an outlier with typical development. A cutoff of ≥ 14% restricted utterances replicated Hoffman's (2009) sensitivity but not specificity. Post hoc analysis of specific error types found sensitivity and specificity rates similar to Hoffman's as well as a significant difference in means when using a proportion of sentence–internal morphosyntactic errors.

Conclusion

Results support further exploration of utterance-level error coding for diagnostic purposes and future development of this approach to meet clinical assessment needs.

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Exploring the Utility of a School-Age Narrative Microstructure Index: Proportion of Restricted Utterances

Purpose

This research attempted to replicate Hoffman's 2009 finding that the proportion of narrative utterances with semantic or syntactic errors (i.e., ≥ 14% “restricted utterances”) can differentiate school-age children with typical development from those with language impairment with a sensitivity of 83% and specificity of 88%.

Method

Methods similar to Hoffman (2009) were used to evaluate an existing set of narratives from 16 age-matched pairs of 8- to 9-year-old children, half with known language impairment. Transcripts were segmented into T-units; a code of [RESTRICTED] was assigned to any utterance with semantic or syntactic errors.

Results

A Welch's t test for independent samples revealed a statistically significant difference in the mean proportion of restricted utterances between the two groups after accommodation for an outlier with typical development. A cutoff of ≥ 14% restricted utterances replicated Hoffman's (2009) sensitivity but not specificity. Post hoc analysis of specific error types found sensitivity and specificity rates similar to Hoffman's as well as a significant difference in means when using a proportion of sentence–internal morphosyntactic errors.

Conclusion

Results support further exploration of utterance-level error coding for diagnostic purposes and future development of this approach to meet clinical assessment needs.

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Exploring the Utility of a School-Age Narrative Microstructure Index: Proportion of Restricted Utterances

Purpose

This research attempted to replicate Hoffman's 2009 finding that the proportion of narrative utterances with semantic or syntactic errors (i.e., ≥ 14% “restricted utterances”) can differentiate school-age children with typical development from those with language impairment with a sensitivity of 83% and specificity of 88%.

Method

Methods similar to Hoffman (2009) were used to evaluate an existing set of narratives from 16 age-matched pairs of 8- to 9-year-old children, half with known language impairment. Transcripts were segmented into T-units; a code of [RESTRICTED] was assigned to any utterance with semantic or syntactic errors.

Results

A Welch's t test for independent samples revealed a statistically significant difference in the mean proportion of restricted utterances between the two groups after accommodation for an outlier with typical development. A cutoff of ≥ 14% restricted utterances replicated Hoffman's (2009) sensitivity but not specificity. Post hoc analysis of specific error types found sensitivity and specificity rates similar to Hoffman's as well as a significant difference in means when using a proportion of sentence–internal morphosyntactic errors.

Conclusion

Results support further exploration of utterance-level error coding for diagnostic purposes and future development of this approach to meet clinical assessment needs.

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Oculoleptomeningeal Amyloidosis associated with transthyretin Leu12Pro in an African patient.

Related Articles

Oculoleptomeningeal Amyloidosis associated with transthyretin Leu12Pro in an African patient.

J Neurol. 2015 Jan;262(1):228-34

Authors: McColgan P, Viegas S, Gandhi S, Bull K, Tudor R, Sheikh F, Pinney J, Fontana M, Rowczenio D, Gillmore JD, Gilbertson JA, Whelan CJ, Shah S, Jaunmuktane Z, Holton JL, Schott JM, Werring DJ, Hawkins PN, Reilly MM

Abstract
Oculoleptomeningeal amyloidosis is a rare manifestation of hereditary transthyretin (TTR) amyloidosis. Here, we present the first case of leptomeningeal amyloidosis associated with the TTR variant Leu12Pro mutation in an African patient. A 43-year-old right-handed Nigerian man was referred to our centre with rapidly progressive neurological decline. He presented initially with weight loss, confusion, fatigue, and urinary and erectile dysfunction. He then suffered recurrent episodes of slurred speech with right-sided weakness. He went on to develop hearing difficulties and painless paraesthesia. Neurological examination revealed horizontal gaze-evoked nystagmus, brisk jaw jerk, increased tone, brisk reflexes throughout and bilateral heel-shin ataxia. Magnetic resonance imaging showed extensive leptomeningeal enhancement. Cerebrospinal fluid analysis showed a raised protein of 6.4 g/dl. Nerve conduction studies showed an axonal neuropathy. Echocardiography was characteristic of cardiac amyloid. TTR gene sequencing showed that he was heterozygous for the leucine 12 proline mutation. Meningeal and brain biopsy confirmed widespread amyloid angiopathy. TTR amyloidosis is a rare cause of leptomeningeal enhancement, but should be considered if there is evidence of peripheral or autonomic neuropathy with cardiac or ocular involvement. The relationship between different TTR mutations and clinical phenotype, disease course, and response to treatment remains unclear.

PMID: 25488473 [PubMed - indexed for MEDLINE]

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Cylindrical spreading due to downwind refraction

Downwind propagation is analyzed for a low level jet (LLJ). The LLJ is characterized by a wind speed maximum (at least 10–20 m/s with peak speeds up to 30 m/s) a few hundred meters above the ground. Close to an elevated point source, such as a wind turbine or an aircraft, spherical spreading results in a 6 dB decrease in sound level per doubling of the distance. Wind turbine noise measurements show that at a transition distance, the downwind propagation changes the spherical spreading into a cylindrical spreading with a 3 dB decrease. It is shown how the transition distance and sound intensity depend on the LLJ parameters. The pivotal phenomenon is the non-coherent superposition of ground reflected rays in the turbulent atmosphere.

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The effect of noise fluctuation and spectral bandwidth on gap detection

Experiment 1 investigated gap detection for random and low-fluctuation noise (LFN) markers as a function of bandwidth (25–1600 Hz), level [40 or 75 dB sound pressure level (SPL)], and center frequency (500–4000 Hz). Gap thresholds for random noise improved as bandwidth increased from 25 to 1600 Hz, but there were only minor effects related to center frequency and level. For narrow bandwidths, thresholds were lower for LFN than random markers; this difference extended to higher bandwidths at the higher center frequencies and was particularly large at high stimulus level. Effects of frequency and level were broadly consistent with the idea that peripheral filtering can increase fluctuation in the encoded LFN stimulus. Experiment 2 tested gap detection for 200-Hz-wide noise bands centered on 2000 Hz, using high-pass maskers to examine spread of excitation effects. Such effects were absent or minor for random noise markers and the 40-dB-SPL LFN markers. In contrast, some high-pass maskers substantially worsened performance for the 75-dB-SPL LFN markers. These results were consistent with an interpretation that relatively acute gap detection for the high-level LFN gap markers resulted from spread of excitation to higher-frequency auditory filters where the magnitude and phase characteristics of the LFN stimuli are better preserved.

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An acoustical study of the qin

The qin (guqin, chi'in) is a seven-string zither of ancient lineage that is prominent in Chinese musical culture. The qin's history is intertwined with philosophy and folklore and its construction is replete with symbolism. The qin was associated with the Imperial aristocracy, and it remains an instrument of high culture. The qin is played with strings horizontal, and the soundbox is made in two halves; the front is usually carved out of paulownia and the back is a flat plate of catalpa. There are two sound holes in the back. It appears that no acoustical study of the qin has been published hitherto. This paper describes vibroacoustic measurements on five examples, the analysis of which reveals the qin's basic sound radiation mechanisms. At low frequencies the qin shows beam bending and torsional modes with some coupling to air in the cavity. At higher frequencies the radiation is dominated by a dense spectrum of mixed cavity and wood modes; the cavity modes are described by a one-dimensional transmission matrix model.

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Rate discrimination at low pulse rates in normal-hearing and cochlear implant listeners: Influence of intracochlear stimulation sitea)

Temporal pitch perception in cochlearimplantees remains weaker than in normal hearing listeners and is usually limited to rates below about 300 pulses per second (pps). Recent studies have suggested that stimulating the apical part of the cochlea may improve the temporal coding of pitch by cochlear implants(CIs), compared to stimulating other sites. The present study focuses on rate discrimination at low pulse rates (ranging from 20 to 104 pps). Two experiments measured and compared pulse rate difference limens (DLs) at four fundamental frequencies (ranging from 20 to 104 Hz) in both CI and normal-hearing (NH) listeners. Experiment 1 measured DLs in users of the (Med-El CI, Innsbruck, Austria) device for two electrodes (one apical and one basal). In experiment 2, DLs for NH listeners were compared for unresolved harmonic complex tones filtered in two frequency regions (lower cut-off frequencies of 1200 and 3600 Hz, respectively) and for different bandwidths. Pulse rate discrimination performance was significantly better when stimulation was provided by the apical electrode in CI users and by the lower-frequency tone complexes in NH listeners. This set of data appears consistent with better temporal coding when stimulation originates from apical regions of the cochlea.

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Music appreciation and music listening in prelingual and postlingually deaf adult cochlear implant recipients

10.3109/14992027.2016.1157630<br/>Michelle Moran

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Music appreciation and music listening in prelingual and postlingually deaf adult cochlear implant recipients

10.3109/14992027.2016.1157630<br/>Michelle Moran

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Music appreciation and music listening in prelingual and postlingually deaf adult cochlear implant recipients

10.3109/14992027.2016.1157630<br/>Michelle Moran

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