scholarly journals Reduced temporal processing in older, normal-hearing listeners evident from electrophysiological responses to shifts in interaural time difference

2016 ◽  
Vol 116 (6) ◽  
pp. 2720-2729 ◽  
Author(s):  
Erol J. Ozmeral ◽  
David A. Eddins ◽  
Ann C. Eddins
Keyword(s):  
Cognitive Processing ◽  
Temporal Processing ◽  
Spatial Perception ◽  
Interaural Time Difference ◽  
Relative Activity ◽  
Time Difference ◽  
Asymmetric Distribution ◽  
Neural Synchrony ◽  
Spatial Cues ◽  
Age Related

Previous electrophysiological studies of interaural time difference (ITD) processing have demonstrated that ITDs are represented by a nontopographic population rate code. Rather than narrow tuning to ITDs, neural channels have broad tuning to ITDs in either the left or right auditory hemifield, and the relative activity between the channels determines the perceived lateralization of the sound. With advancing age, spatial perception weakens and poor temporal processing contributes to declining spatial acuity. At present, it is unclear whether age-related temporal processing deficits are due to poor inhibitory controls in the auditory system or degraded neural synchrony at the periphery. Cortical processing of spatial cues based on a hemifield code are susceptible to potential age-related physiological changes. We consider two distinct predictions of age-related changes to ITD sensitivity: declines in inhibitory mechanisms would lead to increased excitation and medial shifts to rate-azimuth functions, whereas a general reduction in neural synchrony would lead to reduced excitation and shallower slopes in the rate-azimuth function. The current study tested these possibilities by measuring an evoked response to ITD shifts in a narrow-band noise. Results were more in line with the latter outcome, both from measured latencies and amplitudes of the global field potentials and source-localized waveforms in the left and right auditory cortices. The measured responses for older listeners also tended to have reduced asymmetric distribution of activity in response to ITD shifts, which is consistent with other sensory and cognitive processing models of aging.

Temporal processing as a function of age: Interaural time difference discrimination.

2009 ◽  
Vol 125 (4) ◽  
pp. 2722-2722
Author(s):  
John H. Grose ◽  
Sara K. Mamo ◽  
Emily Buss ◽  
Joseph W. Hall
Keyword(s):  
Temporal Processing ◽  
Interaural Time Difference ◽  
Time Difference

scholarly journals Natural ITD statistics predict human auditory spatial perception

2018 ◽  
Author(s):  
Rodrigo Pavão ◽  
Elyse S. Sussman ◽  
Brian J. Fischer ◽  
José L. Peña
Keyword(s):  
Spatial Perception ◽  
Novelty Detection ◽  
Interaural Time Difference ◽  
Subject Area ◽  
Neural Code ◽  
Rate Of Change ◽  
Spatial Cues ◽  
Sensory Cue ◽  
Invariant Statistics ◽  
Natural Statistics

A neural code adapted to the statistical structure of sensory cues may optimize perception. We investigated whether interaural time difference (ITD) statistics inherent in natural acoustic scenes are parameters determining spatial discriminability. The natural ITD rate of change across azimuth (ITDrc) and ITD variability over time (ITDv) were combined in a Fisher information statistic for assessing the amount of azimuthal information conveyed by this sensory cue. We hypothesized that natural ITD statistics drive the neural code for ITD and thus influence spatial perception. Human spatial discriminability and spatial novelty detection of sounds with invariant statistics correlated with natural ITD statistics. The lack of natural statistics in the stimuli suggests that this correlation results from natural statistics driving the neural code. Additionally, the density distribution of ITD tuning matching natural statistics is consistent with classic models of ITD coding and can explain the ITD tuning distribution observed in the mammalian brainstem.Impact statementHuman brain has incorporated natural statistics of spatial cues to the neural code supporting perception of sound location.Major subject areaNeuroscience;Research organismHuman;

scholarly journals The Positive Legacy of Vision Loss: Pathways to Posttraumatic Growth

2020 ◽  
Vol 4 (Supplement_1) ◽  
pp. 616-617
Author(s):  
Corinna Tanner ◽  
Michael Caserta ◽  
Jia-Wen Guo ◽  
Margaret Clayton ◽  
Paul Bernstein ◽  
...  
Keyword(s):  
Posttraumatic Growth ◽  
Cognitive Processing ◽  
Mixed Method ◽  
Vision Loss ◽  
Social Issues ◽  
Qualitative Interviews ◽  
Age Related Macular Degeneration ◽  
Age Related ◽  
Severe Vision Loss ◽  
Age Range

Abstract This mixed method study describes posttraumatic growth (PTG) accruing form experience with vision loss caused by severe age related macular degeneration (AMD) and explores relationships between depression, social support, and cognitive processing, on the path to PTG. Research describing the psychological and social issues surrounding AMD has focused on negative outcomes. However, learning from highly challenging experiences, such as vision loss, can offer benefits. In this study, these included an increased sense of personal strength, increased spirituality, and empathy for others (all domains of PTG). 89 participants with severe vision loss (mean age = 85.3 years, age range = 74–98 years) completed the interviewer-administered composite questionnaire, which identified elements of Tedeschi and Calhoun’s model of PTG. Relationships between variables were examined using path analysis. Findings were contextualized with data from 15 qualitative interviews. Findings underscored the importance of supportive others and deliberate cognitive processing in the path to PTG.

scholarly journals Age-related differences in binaural masking level differences: behavioral and electrophysiological evidence

2018 ◽  
Vol 120 (6) ◽  
pp. 2939-2952 ◽  
Author(s):  
Samira Anderson ◽  
Robert Ellis ◽  
Julie Mehta ◽  
Matthew J. Goupell
Keyword(s):  
Aging Effect ◽  
Normal Hearing ◽  
Behavioral Experiment ◽  
Spatial Cues ◽  
Sound Sources ◽  
Frequency Following Response ◽  
Binaural Processing ◽  
Threshold Difference ◽  
Age Related ◽  
Effects Of Aging

The effects of aging and stimulus configuration on binaural masking level differences (BMLDs) were measured behaviorally and electrophysiologically, using the frequency-following response (FFR) to target brainstem/midbrain encoding. The tests were performed in 15 younger normal-hearing (<30 yr) and 15 older normal-hearing (>60 yr) participants. The stimuli consisted of a 500-Hz target tone embedded in a narrowband (50-Hz bandwidth) or wideband (1,500-Hz bandwidth) noise masker. The interaural phase conditions included NoSo (tone and noise presented interaurally in-phase), NoSπ (noise presented interaurally in-phase and tone presented out-of-phase), and NπSo (noise presented interaurally out-of-phase and tone presented in-phase) configurations. In the behavioral experiment, aging reduced the magnitude of the BMLD. The magnitude of the BMLD was smaller for the NoSo–NπSo threshold difference compared with the NoSo–NoSπ threshold difference, and it was also smaller in narrowband compared with wideband conditions, consistent with previous measurements. In the electrophysiology experiment, older participants had reduced FFR magnitudes and smaller differences between configurations. There were significant changes in FFR magnitude between the NoSo to NoSπ configurations but not between the NoSo to NπSo configurations. The age-related reduction in FFR magnitudes suggests a temporal processing deficit, but no correlation was found between FFR magnitudes and behavioral BMLDs. Therefore, independent mechanisms may be contributing to the behavioral and neural deficits. Specifically, older participants had higher behavioral thresholds than younger participants for the NoSπ and NπSo configurations but had equivalent thresholds for the NoSo configuration. However, FFR magnitudes were reduced in older participants across all configurations. NEW & NOTEWORTHY Behavioral and electrophysiological testing reveal an aging effect for stimuli presented in wideband and narrowband noise conditions, such that behavioral binaural masking level differences and subcortical spectral magnitudes are reduced in older compared with younger participants. These deficits in binaural processing may limit the older participant's ability to use spatial cues to understand speech in environments containing competing sound sources.

scholarly journals Disparity in interaural time difference improves the accuracy of neural representations of individual concurrent narrowband sounds in rat inferior colliculus and auditory cortex

2020 ◽  
Vol 123 (2) ◽  
pp. 695-706
Author(s):  
Lu Luo ◽  
Na Xu ◽  
Qian Wang ◽  
Liang Li
Keyword(s):  
Auditory Cortex ◽  
Inferior Colliculus ◽  
Interaural Time Difference ◽  
Critical Role ◽  
Low Frequency ◽  
Time Difference ◽  
Neural Representation ◽  
Frequency Bands ◽  
Neural Segregation ◽  
Peripheral Auditory System

The central mechanisms underlying binaural unmasking for spectrally overlapping concurrent sounds, which are unresolved in the peripheral auditory system, remain largely unknown. In this study, frequency-following responses (FFRs) to two binaurally presented independent narrowband noises (NBNs) with overlapping spectra were recorded simultaneously in the inferior colliculus (IC) and auditory cortex (AC) in anesthetized rats. The results showed that for both IC FFRs and AC FFRs, introducing an interaural time difference (ITD) disparity between the two concurrent NBNs enhanced the representation fidelity, reflected by the increased coherence between the responses evoked by double-NBN stimulation and the responses evoked by single NBNs. The ITD disparity effect varied across frequency bands, being more marked for higher frequency bands in the IC and lower frequency bands in the AC. Moreover, the coherence between IC responses and AC responses was also enhanced by the ITD disparity, and the enhancement was most prominent for low-frequency bands and the IC and the AC on the same side. These results suggest a critical role of the ITD cue in the neural segregation of spectrotemporally overlapping sounds. NEW & NOTEWORTHY When two spectrally overlapped narrowband noises are presented at the same time with the same sound-pressure level, they mask each other. Introducing a disparity in interaural time difference between these two narrowband noises improves the accuracy of the neural representation of individual sounds in both the inferior colliculus and the auditory cortex. The lower frequency signal transformation from the inferior colliculus to the auditory cortex on the same side is also enhanced, showing the effect of binaural unmasking.

Sign in / Sign up

Export Citation Format

Share Document