Factors affecting gap duration discrimination performance

2005 ◽  
Vol 117 (4) ◽  
pp. 2535-2535
Author(s):  
John H. Grose ◽  
Joseph W. Hall ◽  
Emily Buss
Keyword(s):  
Discrimination Performance ◽  
Duration Discrimination ◽  
Factors Affecting

Developmental Patterns of Duration Discrimination

1993 ◽  
Vol 36 (4) ◽  
pp. 842-849 ◽  
Author(s):  
Jill L. Elfenbein ◽  
Arnold M. Small ◽  
Julia M. Davis
Keyword(s):  
Standard Stimulus ◽  
Discrimination Performance ◽  
Noise Burst ◽  
Duration Discrimination ◽  
Broadband Noise ◽  
Developmental Patterns ◽  
Age Related ◽  
Perceptual Abilities

The purpose of this study was to determine whether the auditory perceptual abilities of children are characterized by an age-related improvement in duration discrimination. Forty children, ages 4 to 10 years, and 10 adults served as subjects. Difference limens were obtained using a 350-msec broadband noise burst as the standard stimulus in a three-interval forcedchoice paradigm. Data were characterized by significant differences between the performances of the 4-, 6-, and 8-year-olds and those of the adults. Acquisition of adult-like discrimination performance was demonstrated between the ages of 8 and 10 years.

scholarly journals Diverse cortical codes for scene segmentation in primate auditory cortex

2015 ◽  
Vol 113 (7) ◽  
pp. 2934-2952 ◽  
Author(s):  
Brian J. Malone ◽  
Brian H. Scott ◽  
Malcolm N. Semple
Keyword(s):  
Spike Train ◽  
Cortical Neurons ◽  
Rhesus Macaques ◽  
Discrimination Performance ◽  
Duration Discrimination ◽  
Stimulus Onset ◽  
Cortical Response ◽  
Substantial Contribution ◽  
Response Patterns ◽  
Amplitude Fluctuations

The temporal coherence of amplitude fluctuations is a critical cue for segmentation of complex auditory scenes. The auditory system must accurately demarcate the onsets and offsets of acoustic signals. We explored how and how well the timing of onsets and offsets of gated tones are encoded by auditory cortical neurons in awake rhesus macaques. Temporal features of this representation were isolated by presenting otherwise identical pure tones of differing durations. Cortical response patterns were diverse, including selective encoding of onset and offset transients, tonic firing, and sustained suppression. Spike train classification methods revealed that many neurons robustly encoded tone duration despite substantial diversity in the encoding process. Excellent discrimination performance was achieved by neurons whose responses were primarily phasic at tone offset and by those that responded robustly while the tone persisted. Although diverse cortical response patterns converged on effective duration discrimination, this diversity significantly constrained the utility of decoding models referenced to a spiking pattern averaged across all responses or averaged within the same response category. Using maximum likelihood-based decoding models, we demonstrated that the spike train recorded in a single trial could support direct estimation of stimulus onset and offset. Comparisons between different decoding models established the substantial contribution of bursts of activity at sound onset and offset to demarcating the temporal boundaries of gated tones. Our results indicate that relatively few neurons suffice to provide temporally precise estimates of such auditory “edges,” particularly for models that assume and exploit the heterogeneity of neural responses in awake cortex.

scholarly journals Factors Affecting Speech Discrimination in Children with Cochlear Implants: Evidence from Early-Implanted Infants

2016 ◽  
Vol 27 (06) ◽  
pp. 480-488 ◽  
Author(s):  
Jennifer Phan ◽  
Derek M. Houston ◽  
Chad Ruffin ◽  
Jonathan Ting ◽  
Rachael Frush Holt
Keyword(s):  
Speech Perception ◽  
Cochlear Implants ◽  
Cochlear Implantation ◽  
Pure Tone ◽  
Early Period ◽  
Discrimination Performance ◽  
Speech Discrimination ◽  
Communication Mode ◽  
Factors Affecting ◽  
Pure Tone Average

Background: To learn words and acquire language, children must be able to discriminate and correctly perceive phonemes. Although there has been much research on the general language outcomes of children with cochlear implants (CIs), little is known about the development of speech perception with regard to specific speech processes, such as speech discrimination. Purpose: The purpose of this study was to investigate the development of speech discrimination in infants with CIs and identify factors that might correlate with speech discrimination skills. Research Design: Using a Hybrid Visual Habituation procedure, we tested infants with CIs on their ability to discriminate the vowel contrast /i/-/u/. We also gathered demographic and audiological information about each infant. Study Sample: Children who had received CIs before 2 yr of age served as participants. We tested the children at two post cochlear implantation intervals: 2–4 weeks post CI stimulation (N = 17) and 6–9 mo post CI stimulation (N = 10). Data Collection and Analysis: The infants’ mean looking times during the novel versus old trials of the experiment were measured. A linear regression model was used to evaluate the relationship between the normalized looking time difference and the following variables: chronological age, age at CI stimulation, gender, communication mode, and best unaided pure-tone average. Results: We found that the best unaided pure-tone average predicted speech discrimination at the early interval. In contrast to some previous speech perception studies that included children implanted before 3 yr of age, age at CI stimulation did not predict speech discrimination performance. Conclusions: The results suggest that residual acoustic hearing before implantation might facilitate speech discrimination during the early period post cochlear implantation; with more hearing experience, communication mode might have a greater influence on the ability to discriminate speech. This and other studies on age at cochlear implantation suggest that earlier implantation might not have as large an effect on speech perception as it does on other language skills.

scholarly journals Factors affecting pitch discrimination performance in a cohort of extensively phenotyped healthy volunteers

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Lauren M. Smith ◽  
Alex J. Bartholomew ◽  
Lauren E. Burnham ◽  
Barbara Tillmann ◽  
Elizabeth T. Cirulli
Keyword(s):  
Healthy Volunteers ◽  
Discrimination Performance ◽  
Pitch Discrimination ◽  
Factors Affecting

scholarly journals Using adaptive psychophysics to identify the neural network reset time in subsecond interval timing

2021 ◽  
Author(s):  
Renata Sadibolova ◽  
Stella Sun ◽  
Devin B. Terhune
Keyword(s):  
Discrimination Performance ◽  
Network Models ◽  
Interval Timing ◽  
Duration Discrimination ◽  
Optimal Timing ◽  
Stimulus Interval ◽  
Optimal Interval ◽  
Neuronal Populations ◽  
Inter Stimulus Interval ◽  
State Dependent

AbstractState-dependent network models of sub-second interval timing propose that duration is encoded in states of neuronal populations that need to reset prior to a novel timing operation to maintain optimal timing performance. Previous research has shown that the approximate boundary of this reset interval can be inferred by varying the inter-stimulus interval between two to-be-timed intervals. However, the estimated boundary of this reset interval is broad (250–500 ms) and remains under-specified with implications for the characteristics of state-dependent network dynamics sub-serving interval timing. Here, we probed the interval specificity of this reset boundary by manipulating the inter-stimulus interval between standard and comparison intervals in two sub-second auditory duration discrimination tasks (100 and 200 ms) and a control (pitch) discrimination task using adaptive psychophysics. We found that discrimination thresholds improved with the introduction of a 333 ms inter-stimulus interval relative to a 250 ms inter-stimulus interval in both duration discrimination tasks, but not in the control task. This effect corroborates previous findings of a breakpoint in the discrimination performance for sub-second stimulus interval pairs as a function of an incremental inter-stimulus delay but more precisely localizes the minimal inter-stimulus delay range. These results suggest that state-dependent networks sub-serving sub-second timing require approximately 250–333 ms for the network to reset to maintain optimal interval timing.

scholarly journals Using Adaptive Psychophysics to Identify the Neural Network Reset Time in Sub-second Interval Timing

2021 ◽  
Author(s):  
Renata Sadibolova ◽  
Stella Sun ◽  
Devin B. Terhune
Keyword(s):  
Interstimulus Interval ◽  
Temporal Discrimination ◽  
Discrimination Performance ◽  
Interval Timing ◽  
Duration Discrimination ◽  
Collective State ◽  
Stimulus Interval ◽  
Neuronal Populations ◽  
State Dependent ◽  
Reset Time

AbstractState dependent network models of sub-second interval timing propose that duration is encoded in states of neuronal populations that need to reset prior to a novel timing operation in order to maintain optimal timing performance. Previous research has shown that the approximate boundary of this reset interval can be inferred by varying the interstimulus interval between two to-be-timed intervals. However, the estimated boundary of this reset interval is broad (250-500ms) and remains underspecified with implications for the characteristics of state dependent network dynamics subserving interval timing. Here we probed the interval specificity of this reset boundary by manipulating the interstimulus interval between standard and comparison intervals in two sub-second auditory duration discrimination tasks (100 and 200ms) and a control (pitch) discrimination task using adaptive psychophysics. We found that discrimination thresholds improved with the introduction of a 333ms interstimulus interval relative to a 250ms interstimulus interval in both duration discrimination tasks, but not in the control task. This effect corroborates previous findings of a breakpoint in the discrimination performance for sub-second stimulus interval pairs as a function of an incremental interstimulus delay but more precisely localizes the minimal interstimulus delay range. These results suggest that state dependent networks subserving sub-second timing require approximately 250-333ms for the network to reset in order to maintain optimal interval timing.New & NoteworthyThe state-dependent-network model considers interval timing as an intrinsic ability of neuronal populations to track the temporal evolution of their collective state. However, the time-dependent nature of neuronal properties imposes constraints on a maximum encodable interval and on the processing of intervals that are presented before the network resets to its baseline state. Investigating temporal discrimination thresholds as a function of variable inter-stimulus-intervals, we showed that the network reset time is between 250 and 333ms.

Progress In The Practical Application Of Automated Image Analysis To Tem Negatives

1977 ◽  
Vol 35 ◽  
pp. 214-217
Author(s):  
F. A. Heckman ◽  
E. Redman ◽  
J.E. Connolly
Keyword(s):  
Image Analysis ◽  
Image Quality ◽  
Exposure Time ◽  
Image Contrast ◽  
Automated Image Analysis ◽  
Practical Application ◽  
Factors Affecting ◽  
High Image Quality ◽  
Qualitative Evidence ◽  
Comprehensive Study

In our initial publication on this subject1) we reported results demonstrating that contrast is the most important factor in producing the high image quality required for reliable image analysis. We also listed the factors which enhance contrast in order of the experimentally determined magnitude of their effect. The two most powerful factors affecting image contrast attainable with sheet film are beam intensity and KV. At that time we had only qualitative evidence for the ranking of enhancing factors. Later we carried out the densitometric measurements which led to the results outlined below.Meaningful evaluations of the cause-effect relationships among the considerable number of variables in preparing EM negatives depend on doing things in a systematic way, varying only one parameter at a time. Unless otherwise noted, we adhered to the following procedure evolved during our comprehensive study:Philips EM-300; 30μ objective aperature; magnification 7000- 12000X, exposure time 1 second, anti-contamination device operating.

Factors affecting microstructural scale in liquid crystalline polymers

1990 ◽  
Vol 48 (4) ◽  
pp. 220-221
Author(s):  
Christine M. Dannels ◽  
Christopher Viney
Keyword(s):  
Liquid Crystalline ◽  
Liquid Crystalline Polymers ◽  
Factors Affecting ◽  
Crystalline Polymers ◽  
Thermal Expansion Coefficients ◽  
Low Thermal Expansion ◽  
Lower Viscosity ◽  
Fine Microstructure ◽  
Planar Orientation ◽  
Strength And Stiffness

Processing polymers from the liquid crystalline state offers several advantages compared to processing from conventional fluids. These include: better axial strength and stiffness in fibers, better planar orientation in films, lower viscosity during processing, low solidification shrinkage of injection moldings (thermotropic processing), and low thermal expansion coefficients. However, the compressive strength of the solid is disappointing. Previous efforts to improve this property have focussed on synthesizing stiffer molecules. The effect of microstructural scale has been overlooked, even though its relevance to the mechanical and physical properties of more traditional materials is well established. By analogy with the behavior of metals and ceramics, one would expect a fine microstructure (i..e. a high density of orientational defects) to be desirable.Also, because much microstructural detail in liquid crystalline polymers occurs on a scale close to the wavelength of light, light is scattered on passing through these materials.

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