scholarly journals Repetition detection and rapid auditory learning for stochastic tone clouds

2021 ◽  
Author(s):  
Trevor Agus ◽  
Daniel Pressnitzer
Keyword(s):  
Amplitude Modulation ◽  
Task Difficulty ◽  
Full Range ◽  
Auditory Memory ◽  
Perceptual Range ◽  
Experimental Conditions ◽  
Auditory Learning ◽  
Rapid Learning ◽  
Repetition Detection ◽  
Neurophysiological Studies

Stochastic sounds are useful to probe auditory memory, as they require listeners to learn unpredictable and novel patterns under controlled experimental conditions. Previous studies using white noise or random click trains have demonstrated rapid auditory learning for instances of such a class of sounds. Here, we tested stochastic sounds that enabled parametrical control of spectrotemporal complexity: tone clouds. Tone clouds were defined as broadband combinations of tone pips at randomized frequencies and onset times. Varying the density of tones covered a perceptual range from random melodies to noise. Results showed that listeners could detect repeating patterns in tone clouds at all tested densities, with sparse tone clouds being the easiest. A model estimating amplitude modulation within cochlear filters showed that repetition detection was correlated with the amount of amplitude modulation at lower rates. Rapid learning of individual tone clouds was also observed, again for all densities. Tone clouds thus provide a tool to probe auditory learning in a variety of task-difficulty settings, which could be useful for clinical or neurophysiological studies. They also show that rapid auditory learning operates over the full range of spectrotemporal complexity typical of natural sounds, essentially from melodies to noise.

Covert orienting of attention in macaques. I. Effects of behavioral context

1993 ◽  
Vol 70 (1) ◽  
pp. 431-443 ◽  
Author(s):  
E. M. Bowman ◽  
V. J. Brown ◽  
C. Kertzman ◽  
U. Schwarz ◽  
D. L. Robinson
Keyword(s):  
Cognitive Processes ◽  
Reaction Times ◽  
Orienting Response ◽  
Validity Effect ◽  
Experimental Conditions ◽  
Covert Orienting ◽  
Cognitive Influences ◽  
Attentional Effect ◽  
Peripheral Cues ◽  
Neurophysiological Studies

1. A task was used by Posner (1980) to measure shifts of attention that occurred covertly, in the absence of an eye movement or other orienting response. This paradigm was used here to assess the nature of covert attentional orienting in monkeys to develop an animal model for neurophysiological studies. Shifts of attention were measurable in monkeys and were consistent across a variety of experimental conditions. 2. The paradigm required that monkeys fixate and release a bar at the appearance of a target, which was preceded by a cue. Reaction times to targets that followed peripheral cues at the same location (validly cued) were significantly faster than those that followed cues in the opposite visual field (invalidly cued). This difference was defined as the validity effect, which as in humans, is used as the measure of a covert attentional shift. 3. When the proportion of validly to invalidly cued targets was decreased, no change was seen in the validity effect of the monkeys. This is in contrast to humans, for whom the ratio of validly to invalidly cued targets affected the magnitude of the validity effect. When 80% of the targets were preceded by cues at the same location, the validity effect was greatest. The effect was reversed when the proportions were reversed. From this result, it is concluded that cognitive processes can affect covert orienting to peripheral cues in humans, whereas in trained monkeys, performance was automatic. 4. To test whether cognitive influences on attention could be demonstrated in the monkey, an animal was taught to use symbolic, foveal signals to covertly direct attention. The magnitude of this validity effect was greater than that obtained with peripheral cues. 5. The effects of motivational and perceptual processes were tested. Although overall reaction times could be modified, the facilitating effects of the cues persisted. This constancy across motivational and perceptual levels supports the notion that the monkeys were performing the task in an automatic way, under the exogenous control of peripheral cues. 6. Most visual cuing has been tested with visual landmarks at the locations of cues and targets. These monkeys were trained with such landmarks, and when tested without them, the attentional effect of the cues was nearly abolished. These data suggest that local visual features can be important for covert orienting. 7. To determine the spatial extent of the effect of the cue, monkeys and humans were tested with four cue-target distances (0-60 degrees).(ABSTRACT TRUNCATED AT 400 WORDS)

Effect on the Cushing response of different rates of expansion of a supratentorial mass

1978 ◽  
Vol 49 (1) ◽  
pp. 61-70 ◽  
Author(s):  
Abdul Hamid Zidan ◽  
John P. Girvin
Keyword(s):  
Heart Rate ◽  
Full Range ◽  
Blood Gases ◽  
Systemic Arterial Pressure ◽  
Critical Volume ◽  
Experimental Conditions ◽  
Content Type ◽  
Cerebral Dysfunction ◽  
Cushing Response ◽  
Supratentorial Mass

✓ The effects on the three components (respiration, blood pressure, and heart rate) of the Cushing response (CR) were studied in cats by the continuous expansion of a supratentorial balloon. The rate of expansion was varied over the range of 0.006 to 0.6 ml/min, during which systemic arterial pressure, heart rate, respiratory rate, and blood gases were monitored. For the different rates the time the CR took to develop, and the balloon volume required for that development were measured. The final volume (“critical volume”) for eliciting the CR was more or less constant over the full range of rates of infusion (balloon expansion), a fact that supports the Monro-Kellie doctrine. This constancy of critical volume (CCV) gives rise to a highly statistically significant relationship between the rate of infusion and the latency to the production of the CR, and it is described by a power curve. Thus the development of cerebral dysfunction under these experimental conditions is independent of the rate of expansion and only dependent upon this critical volume. Exceptions to this concept of a critical volume, at the extreme of rates of expansion of lesions in patients, are predicted.

scholarly journals Auditory Cortical Changes Precede Brainstem Changes During Rapid Implicit Learning: Evidence From Human EEG

2021 ◽  
Vol 15 ◽  
Author(s):  
Erika Skoe ◽  
Jennifer Krizman ◽  
Emily R. Spitzer ◽  
Nina Kraus
Keyword(s):  
Young Adults ◽  
Auditory Brainstem ◽  
Pattern Learning ◽  
Subcortical Structures ◽  
Auditory Pattern ◽  
Auditory Learning ◽  
Rapid Learning ◽  
Functional Changes ◽  
Learning Conditions ◽  
Electroencephalogram Eeg

The auditory system is sensitive to stimulus regularities such as frequently occurring sounds and sound combinations. Evidence of regularity detection can be seen in how neurons across the auditory network, from brainstem to cortex, respond to the statistical properties of the soundscape, and in the rapid learning of recurring patterns in their environment by children and adults. Although rapid auditory learning is presumed to involve functional changes to the auditory network, the chronology and directionality of changes are not well understood. To study the mechanisms by which this learning occurs, auditory brainstem and cortical activity was simultaneously recorded via electroencephalogram (EEG) while young adults listened to novel sound streams containing recurring patterns. Neurophysiological responses were compared between easier and harder learning conditions. Collectively, the behavioral and neurophysiological findings suggest that cortical and subcortical structures each provide distinct contributions to auditory pattern learning, but that cortical sensitivity to stimulus patterns likely precedes subcortical sensitivity.

Reshaping biological membranes in endocytosis: crossing the configurational space of membrane-protein interactions

2014 ◽  
Vol 395 (3) ◽  
pp. 275-283 ◽  
Author(s):  
Mijo Simunovic ◽  
Patricia Bassereau
Keyword(s):  
Membrane Protein ◽  
Protein Interactions ◽  
Molecular Mechanisms ◽  
Full Range ◽  
Biological Membranes ◽  
Membrane Properties ◽  
Physical Parameters ◽  
Membrane Remodeling ◽  
Experimental Conditions ◽  
The Way

Abstract Lipid membranes are highly dynamic. Over several decades, physicists and biologists have uncovered a number of ways they can change the shape of membranes or alter their phase behavior. In cells, the intricate action of membrane proteins drives these processes. Considering the highly complex ways proteins interact with biological membranes, molecular mechanisms of membrane remodeling still remain unclear. When studying membrane remodeling phenomena, researchers often observe different results, leading them to disparate conclusions on the physiological course of such processes. Here we discuss how combining research methodologies and various experimental conditions contributes to the understanding of the entire phase space of membrane-protein interactions. Using the example of clathrin-mediated endocytosis we try to distinguish the question ‘how can proteins remodel the membrane?’ from ‘how do proteins remodel the membrane in the cell?’ In particular, we consider how altering physical parameters may affect the way membrane is remodeled. Uncovering the full range of physical conditions under which membrane phenomena take place is key in understanding the way cells take advantage of membrane properties in carrying out their vital tasks.

scholarly journals Atmospheric isoprene ozonolysis: impacts of stabilized Criegee intermediate reactions with SO<sub>2</sub>, H<sub>2</sub>O and dimethyl sulfide

2015 ◽  
Vol 15 (6) ◽  
pp. 8839-8881 ◽  
Author(s):  
M. J. Newland ◽  
A. R. Rickard ◽  
L. Vereecken ◽  
A. Muñoz ◽  
M. Ródenas ◽  
...  
Keyword(s):  
Rate Constant ◽  
Dimethyl Sulfide ◽  
Relative Rate ◽  
Full Range ◽  
Substantial Contribution ◽  
Sulfide Concentration ◽  
Relative Rate Constant ◽  
So2 Oxidation ◽  
Experimental Conditions ◽  
So2 Removal

Abstract. Isoprene is the dominant global biogenic volatile organic compound (VOC) emission. Reactions of isoprene with ozone are known to form stabilised Criegee intermediates (SCIs), which have recently been shown to be potentially important oxidants for SO2 and NO2 in the atmosphere; however the significance of this chemistry for SO2 processing (affecting sulfate aerosol) and NO2 processing (affecting NOx levels) depends critically upon the fate of the SCI with respect to reaction with water and decomposition. Here, we have investigated the removal of SO2 in the presence of isoprene and ozone, as a function of humidity, under atmospheric boundary layer conditions. The SO2 removal displays a clear dependence on relative humidity, confirming a significant reaction for isoprene derived SCI with H2O. Under excess SO2 conditions, the total isoprene ozonolysis SCI yield was calculated to be 0.56 (±0.03). The observed SO2 removal kinetics are consistent with a relative rate constant, k(SCI + H2O)/k(SCI + SO2), of 5.4 (±0.8) × 10−5 for isoprene derived SCI. The relative rate constant for k(SCI decomposition)/k(SCI + SO2) is 8.4 (±5.0) × 1010 cm−3. Uncertainties are ±2σ and represent combined systematic and precision components. These kinetic parameters are based on the simplification that a single SCI species is formed in isoprene ozonolysis, an approximation which describes the results well across the full range of experimental conditions. Our data indicate that isoprene-derived SCIs are unlikely to make a substantial contribution to gas-phase SO2 oxidation in the troposphere. We also present results from an analogous set of experiments, which show a clear dependence of SO2 removal in the isoprene-ozone system as a function of dimethyl sulfide concentration. We propose that this behaviour arises from a rapid reaction between isoprene-derived SCI and DMS; the observed SO2 removal kinetics are consistent with a relative rate constant, k(SCI + DMS)/k(SCI + SO2), of 4.1 (±2.2). This result suggests that SCIs may contribute to the oxidation of DMS in the atmosphere and that this process could therefore influence new particle formation in regions impacted by emissions of unsaturated hydrocarbons and DMS.

Hysteresis in Mental Workload and Task Performance

2016 ◽  
Vol 58 (8) ◽  
pp. 1143-1157 ◽  
Author(s):  
Reinier J. Jansen ◽  
Ben D. Sawyer ◽  
René van Egmond ◽  
Huib de Ridder ◽  
Peter A. Hancock
Keyword(s):  
Mental Workload ◽  
Memory Task ◽  
Task Demands ◽  
Auditory Memory ◽  
Task Demand ◽  
Experimental Conditions ◽  
Lane Changing ◽  
Transient Nature ◽  
Hysteretic Effect ◽  
And Performance

Objective: We examine how transitions in task demand are manifested in mental workload and performance in a dual-task setting. Background: Hysteresis has been defined as the ongoing influence of demand levels prior to a demand transition. Authors of previous studies predominantly examined hysteretic effects in terms of performance. However, little is known about the temporal development of hysteresis in mental workload. Method: A simulated driving task was combined with an auditory memory task. Participants were instructed to prioritize driving or to prioritize both tasks equally. Three experimental conditions with low, high, and low task demands were constructed by manipulating the frequency of lane changing. Multiple measures of subjective mental workload were taken during experimental conditions. Results: Contrary to our prediction, no hysteretic effects were found after the high- to low-demand transition. However, a hysteretic effect in mental workload was found within the high-demand condition, which degraded toward the end of the high condition. Priority instructions were not reflected in performance. Conclusion: Online assessment of both performance and mental workload demonstrates the transient nature of hysteretic effects. An explanation for the observed hysteretic effect in mental workload is offered in terms of effort regulation. Application: An informed arrival at the scene is important in safety operations, but peaks in mental workload should be avoided to prevent buildup of fatigue. Therefore, communication technologies should incorporate the historical profile of task demand.

scholarly journals Cognitive Algebra Underlying High School Student´s Self-Efficacy Judgment to Solve Mathematical Problems in the Classroom or Online

2016 ◽  
Vol 8 (2) ◽  
pp. 136
Author(s):  
Carlos Briones-Rodriguez ◽  
Guadalupe Elizabeth Morales-Martinez ◽  
Maria Guadalupe Santos-Alcantara ◽  
Ernesto Octavio Lopez-Ramirez ◽  
Maria Elena Urdiales-Ibarra
Keyword(s):  
High School ◽  
High School Students ◽  
Self Efficacy ◽  
Task Difficulty ◽  
Math Skills ◽  
School Students ◽  
Experimental Conditions ◽  
Mathematical Problems ◽  
Summation Rule ◽  
Math Problems

<p>This study includes a sample of 112 high school students who provided self-efficacy<br />judgments to solve math problems. Thirty-six experimental conditions called scenarios were<br />created for this study by combining 4 factors regarding solving mathematical problems<br />(modality, degree of difficulty, structuring, and relevance of the task). Each scenario<br />described a hypothetical context that required the participant to imagine an activity to<br />reinforce the learning of math skills in the scenario. Thus, the experimental task was to read<br />each scenario and to judge how capable the participant felt to undertake each math task under<br />the hypothetical context. Results showed two levels of self-efficacy judgment among<br />participants. Students in the first level judged themselves as highly capable of performing<br />math activities, while those in the second level, judged themselves as moderate capable.<br />Regarding the first cluster factors regarding difficulty and the structure of the task had a<br />greater weight whereas in the second cluster task difficulty and task relevance factors<br />obtained the higher weight values. Finally, a cognitive summation rule used by participants to<br />integrate information from the different study factors was identified. Results implications on<br />education are discussed in this article.</p>

scholarly journals Embedding single-cell experimental conditions to reveal manifold structure of cancer drug perturbation effects

2018 ◽  
Author(s):  
William S. Chen ◽  
Nevena Zivanovic ◽  
David van Dijk ◽  
Guy Wolf ◽  
Bernd Bodenmiller ◽  
...  
Keyword(s):  
Single Cell ◽  
State Space ◽  
Expression Profiles ◽  
Full Range ◽  
New Drugs ◽  
Cancer Drug ◽  
Experimental Conditions ◽  
Manifold Structure ◽  
Cell Technologies ◽  
Analytical Approaches

AbstractPreviously, the effect of a drug on a cell population was measured based on simple metrics such as cell viability. However, as single-cell technologies are becoming more advanced, drug screen experiments can now be conducted with more complex readouts such as gene expression profiles of individual cells. The increasing complexity of measurements from these multi-sample experiments calls for more sophisticated analytical approaches than are currently available. We developed a novel method called PhEMD (Phenotypic Earth Mover’s Distance) and show that it can be used to embed the space of drug perturbations on the basis of the drugs’ effects on cell populations. When testing PhEMD on a newly-generated, 300-sample CyTOF kinase inhibition screen experiment, we find that the state space of the perturbation conditions is surprisingly low-dimensional and that the network of drugs demonstrates manifold structure. We show that because of the fairly simple manifold geometry of the 300 samples, we can accurately capture the full range of drug effects using a dictionary of only 30 experimental conditions. We also show that new drugs can be added to our PhEMD embedding using similarities inferred from other characterizations of drugs using a technique called Nystrom extension. Our findings suggest that large-scale drug screens can be conducted by measuring only a small fraction of the drugs using the most expensive high-throughput single-cell technologies—the effects of other drugs may be inferred by mapping and extending the perturbation space. We additionally show that PhEMD can be useful for analyzing other types of single-cell samples, such as patient tumor biopsies, by mapping the patient state space in a similar way as the drug state space. We demonstrate that PhEMD is scalable, compatible with leading batch effect correction techniques, and generalizable to multiple experimental designs. Altogether, our analyses suggest that PhEMD may facilitate drug discovery efforts and help uncover the network geometry of a collection of single-cell samples.

scholarly journals Sound frequency-invariant neural coding of a frequency-dependent cue to sound source location

2015 ◽  
Vol 114 (1) ◽  
pp. 531-539 ◽  
Author(s):  
Heath G. Jones ◽  
Andrew D. Brown ◽  
Kanthaiah Koka ◽  
Jennifer L. Thornton ◽  
Daniel J. Tollin
Keyword(s):  
Sound Source ◽  
High Frequency ◽  
Neural Coding ◽  
Full Range ◽  
Low Frequency ◽  
Biologically Relevant ◽  
Behavioral Studies ◽  
Neurophysiological Studies ◽  
Behavioral Sensitivity ◽  
Duplex Theory

The century-old duplex theory of sound localization posits that low- and high-frequency sounds are localized with two different acoustical cues, interaural time and level differences (ITDs and ILDs), respectively. While behavioral studies in humans and behavioral and neurophysiological studies in a variety of animal models have largely supported the duplex theory, behavioral sensitivity to ILD is curiously invariant across the audible spectrum. Here we demonstrate that auditory midbrain neurons in the chinchilla ( Chinchilla lanigera) also encode ILDs in a frequency-invariant manner, efficiently representing the full range of acoustical ILDs experienced as a joint function of sound source frequency, azimuth, and distance. We further show, using Fisher information, that nominal “low-frequency” and “high-frequency” ILD-sensitive neural populations can discriminate ILD with similar acuity, yielding neural ILD discrimination thresholds for near-midline sources comparable to behavioral discrimination thresholds estimated for chinchillas. These findings thus suggest a revision to the duplex theory and reinforce ecological and efficiency principles that hold that neural systems have evolved to encode the spectrum of biologically relevant sensory signals to which they are naturally exposed.

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