scholarly journals Changes in absolute detection threshold and in subjective intensity of suprathreshold stimuli during olfactory adaptation and recovery

1970 ◽  
Vol 8 (5) ◽  
pp. 331-335 ◽  
Author(s):  
Gordon T. Pryor ◽  
Gerald Steinmetz ◽  
Herbert Stone
Keyword(s):  
Detection Threshold ◽  
Subjective Intensity ◽  
Olfactory Adaptation

Capacities of humans and monkeys to discriminate vibratory stimuli of different frequency and amplitude: a correlation between neural events and psychological measurements

1975 ◽  
Vol 38 (3) ◽  
pp. 539-559 ◽  
Author(s):  
R. H. LaMotte ◽  
V. B. Mountcastle
Keyword(s):  
Detection Threshold ◽  
Absolute Threshold ◽  
Frequency Discrimination ◽  
Total Activity ◽  
Difference Limen ◽  
Small Population ◽  
Neural Population ◽  
Active Population ◽  
Subjective Intensity ◽  
The Difference

The capacities of monkeys and humans to discriminate between mechanical sinusoids differing in amplitude or frequency were measured in a two-alternative, forced-choice task. The difference limen for amplitude discrimination for both species remained constant near 10% of the standard amplitude over the range of 17-30 dB, relative to detection threshold. Equal subjective intensity curves in the 20-40 Hz range were determined at 20 and 29 dB, relative to detection threshold. These curves followed the threshold curve and were identical for the two species. The difference limen for frequency discrimination averaged 1.8 Hz for humans and 2.7 Hz for monkeys; the range of values for the two species overlapped nearly completely. The small sizes of these difference limens indicate, we believe, the capacity of highly trained individuals of either species to ascertain small differences in the temporal order of somesthetic stimuli and of the neural events evoked by them. In one series of experiments we demonstrated that subjects of both species possess two threshold for two different aspects of flutter-vibration which are displaced from each other along the intensive continuum. For either species, the minimum level of stimulus amplitude required for threshold frequency discrimination is about 8 dB above that sufficient for detection. This difference in amplitude is called the atonal interval and matches that observed between absolute and tuning thresholds for quickly adapting, mechanoreceptor afferents (the Meissner afferents) which innervate the glabrous skin of the monkey hand. These and previous findings have permitted a number of direct correlations between behavioral and neural events as regards the sense of flutter. The neural codes for the intensity and frequency of flutter appear to be different. The capacity to detect the presence of a mechanical sinusoid and the capacity to judge its subjective intensity are likely to depend on criterion levels of activity in the total population of Meissner afferents, the former on the appearance of any activity (absolute threshold) in a small population of the most sensitive of these fibers and the latter on the overall size of the active population of neuronal elements at each level of amplitude. The total activity in the relevant neural population elicited by sinusoids of increasing amplitude defines a prothetic continuum along which subjects can judge the magnitude of sensation..

Detection threshold for electric shock in psychopaths.

1968 ◽  
Vol 73 (3, Pt.1) ◽  
pp. 268-272 ◽  
Author(s):  
Robert D. Hare
Keyword(s):  
Electric Shock ◽  
Detection Threshold

Absolute pitch ability is not associated with advantage in musical tension processing

2020 ◽  
Author(s):  
Linshu Zhou ◽  
Fang Liu ◽  
Tang Hai ◽  
Jun Jiang ◽  
Dongrui Man ◽  
...  
Keyword(s):  
Detection Threshold ◽  
Absolute Pitch ◽  
Discrimination Threshold ◽  
Pitch Change ◽  
Letter Naming ◽  
Direction Discrimination ◽  
Pitch Direction ◽  
Lower Accuracy ◽  
Tonal Hierarchy ◽  
The Stability

Absolute pitch (AP), a superior ability of pitch letter naming in the absence of a reference note, has long been viewed as an indicator of human musical talent and thus as evidence for the adaptationist hypothesis of music evolution. Little is known, however, whether AP possessors are superior to non-AP possessors in music processing. The present study investigated whether the AP ability facilitates musical tension processing in perceptual and experienced tasks. Twenty-one AP possessors and 21 matched non-AP possessors were tested using novel melodies in C and non-C contexts. Results indicated that the two groups provided comparable ratings of perceived and felt tension for melodies in both contexts. While AP possessors demonstrated lower accuracy with longer reaction time than non-AP possessors in naming movable solfège syllables for pitch in the pretest, their tension rating profiles showed a similar tonal hierarchy as non-AP possessors in regard to the stability of the ending tones of the melodies in both major and minor keys. Correlation analyses suggested that musical tension ratings were not significantly related to performance in pitch letter, movable solfège syllable naming, pitch change detection threshold, or pitch direction discrimination threshold for either group. These findings suggest that pitch naming abilities (either pitch letter or movable solfège syllable naming) do not benefit processing of perceived or felt musical tension, providing evidence to support the hypothesis that AP ability is not associated with advantage in music processing.

ARFIS: Adaptive-Receiver-Based Fuzzy Inference System for Diffusion- Based Molecular Communications

2020 ◽  
Vol 16 (2) ◽  
pp. 280-289
Author(s):  
Ghalib H. Alshammri ◽  
Walid K. M. Ahmed ◽  
Victor B. Lawrence
Keyword(s):  
Fuzzy Inference System ◽  
Fuzzy Inference ◽  
Detection Threshold ◽  
Learning Rule ◽  
Optimal Number ◽  
Molecular Communication ◽  
Inference System ◽  
Detection Scheme ◽  
Adaptive Receiver ◽  
Detection Schemes

Background: The architecture and sequential learning rule-based underlying ARFIS (adaptive-receiver-based fuzzy inference system) are proposed to estimate and predict the adaptive threshold-based detection scheme for diffusion-based molecular communication (DMC). Method: The proposed system forwards an estimate of the received bits based on the current molecular cumulative concentration, which is derived using sequential training-based principle with weight and bias and an input-output mapping based on both human knowledge in the form of fuzzy IFTHEN rules. The ARFIS architecture is employed to model nonlinear molecular communication to predict the received bits over time series. Result: This procedure is suitable for binary On-OFF-Keying (Book signaling), where the receiver bio-nanomachine (Rx Bio-NM) adapts the 1/0-bit detection threshold based on all previous received molecular cumulative concentrations to alleviate the inter-symbol interference (ISI) problem and reception noise. Conclusion: Theoretical and simulation results show the improvement in diffusion-based molecular throughput and the optimal number of molecules in transmission. Furthermore, the performance evaluation in various noisy channel sources shows promising improvement in the un-coded bit error rate (BER) compared with other threshold-based detection schemes in the literature.

scholarly journals Field Theoretical Approach for Signal Detection in Nearly Continuous Positive Spectra II: Tensorial Data

Entropy ◽  
2021 ◽  
Vol 23 (7) ◽  
pp. 795
Author(s):  
Vincent Lahoche ◽  
Mohamed Ouerfelli ◽  
Dine Ousmane Samary ◽  
Mohamed Tamaazousti
Keyword(s):  
Principal Component Analysis ◽  
Renormalization Group ◽  
Signal Detection ◽  
Detection Threshold ◽  
Principal Component ◽  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Component Analysis ◽  
Slight Generalization ◽  
Nearly Continuous

The tensorial principal component analysis is a generalization of ordinary principal component analysis focusing on data which are suitably described by tensors rather than matrices. This paper aims at giving the nonperturbative renormalization group formalism, based on a slight generalization of the covariance matrix, to investigate signal detection for the difficult issue of nearly continuous spectra. Renormalization group allows constructing an effective description keeping only relevant features in the low “energy” (i.e., large eigenvalues) limit and thus providing universal descriptions allowing to associate the presence of the signal with objectives and computable quantities. Among them, in this paper, we focus on the vacuum expectation value. We exhibit experimental evidence in favor of a connection between symmetry breaking and the existence of an intrinsic detection threshold, in agreement with our conclusions for matrices, providing a new step in the direction of a universal statement.

scholarly journals Evidence accumulation relates to perceptual consciousness and monitoring

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Michael Pereira ◽  
Pierre Megevand ◽  
Mi Xue Tan ◽  
Wenwen Chang ◽  
Shuo Wang ◽  
...  
Keyword(s):  
Posterior Parietal Cortex ◽  
Detection Threshold ◽  
Task Demands ◽  
Neuron Activity ◽  
Neural Responses ◽  
Neuronal Responses ◽  
Neural Basis ◽  
Perceptual Consciousness ◽  
Evidence Accumulation ◽  
Posterior Parietal

AbstractA fundamental scientific question concerns the neural basis of perceptual consciousness and perceptual monitoring resulting from the processing of sensory events. Although recent studies identified neurons reflecting stimulus visibility, their functional role remains unknown. Here, we show that perceptual consciousness and monitoring involve evidence accumulation. We recorded single-neuron activity in a participant with a microelectrode in the posterior parietal cortex, while they detected vibrotactile stimuli around detection threshold and provided confidence estimates. We find that detected stimuli elicited neuronal responses resembling evidence accumulation during decision-making, irrespective of motor confounds or task demands. We generalize these findings in healthy volunteers using electroencephalography. Behavioral and neural responses are reproduced with a computational model considering a stimulus as detected if accumulated evidence reaches a bound, and confidence as the distance between maximal evidence and that bound. We conclude that gradual changes in neuronal dynamics during evidence accumulation relates to perceptual consciousness and perceptual monitoring in humans.

scholarly journals HIV Drug Resistance Mutations Detection by Next-Generation Sequencing during Antiretroviral Therapy Interruption in China

Pathogens ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 264
Author(s):  
Miaomiao Li ◽  
Shujia Liang ◽  
Chao Zhou ◽  
Min Chen ◽  
Shu Liang ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Next Generation Sequencing ◽  
Antiretroviral Therapy ◽  
Detection Threshold ◽  
Next Generation ◽  
Resistance Mutations ◽  
Hiv Drug Resistance ◽  
Drug Resistance Mutations ◽  
Therapy Interruption ◽  
Generation Sequencing

Patients with antiretroviral therapy interruption have a high risk of virological failure when re-initiating antiretroviral therapy (ART), especially those with HIV drug resistance. Next-generation sequencing may provide close scrutiny on their minority drug resistance variant. A cross-sectional study was conducted in patients with ART interruption in five regions in China in 2016. Through Sanger and next-generation sequencing in parallel, HIV drug resistance was genotyped on their plasma samples. Rates of HIV drug resistance were compared by the McNemar tests. In total, 174 patients were included in this study, with a median 12 (interquartile range (IQR), 6–24) months of ART interruption. Most (86.2%) of them had received efavirenz (EFV)/nevirapine (NVP)-based first-line therapy for a median 16 (IQR, 7–26) months before ART interruption. Sixty-one (35.1%) patients had CRF07_BC HIV-1 strains, 58 (33.3%) CRF08_BC and 35 (20.1%) CRF01_AE. Thirty-four (19.5%) of the 174 patients were detected to harbor HIV drug-resistant variants on Sanger sequencing. Thirty-six (20.7%), 37 (21.3%), 42 (24.1%), 79 (45.4%) and 139 (79.9) patients were identified to have HIV drug resistance by next-generation sequencing at 20% (v.s. Sanger, p = 0.317), 10% (v.s. Sanger, p = 0.180), 5% (v.s. Sanger, p = 0.011), 2% (v.s. Sanger, p < 0.001) and 1% (v.s. Sanger, p < 0.001) of detection thresholds, respectively. K65R was the most common minority mutation, of 95.1% (58/61) and 93.1% (54/58) in CRF07_BC and CRF08_BC, respectively, when compared with 5.7% (2/35) in CRF01_AE (p < 0.001). In 49 patients that followed-up a median 10 months later, HIV drug resistance mutations at >20% frequency such as K103N, M184VI and P225H still existed, but with decreased frequencies. The prevalence of HIV drug resistance in ART interruption was higher than 15% in the survey. Next-generation sequencing was able to detect more minority drug resistance variants than Sanger. There was a sharp increase in minority drug resistance variants when the detection threshold was below 5%.

scholarly journals Sympathetic and sensory nerve fiber function in multiple system atrophy and idiopathic Parkinson’s disease

2021 ◽  
Author(s):  
Heidrun H. Krämer ◽  
Cora Rebhorn ◽  
Christian Geber ◽  
Frank Birklein
Keyword(s):  
Detection Threshold ◽  
Sensory Nerve ◽  
Research Network ◽  
Sensory Testing ◽  
Sympathetic Function ◽  
Autonomic Testing ◽  
German Research ◽  
Pain Sensitization ◽  
Mechanical Detection ◽  
Mechanical Pain Thresholds

Abstract Objective To explore small fiber somatosensory and sympathetic function in PD and MSA. Methods We recruited 20 PD patients (7 women, median age 65.5 years; IQR 54.75–70.0), 10 MSA patients (4 women; median age 68 years; IQR 66.25–74.0), and 10 healthy subjects (HC; 4 women, median age 68; IQR 59.0–71.0 years). Autonomic testing included forehead cooling, intradermal microdialysis of norepinephrine (NE; 10–5; 10–6; 10–7; and 10–8), and orthostatic hypotension (OH); somatosensory testing included quantitative sensory testing (QST) according to the protocol of the German Research Network on Neuropathic Pain (DFNS). Results OH occurred more frequently in PD (p = 0.018) and MSA (p = 0.002) compared to HC. Vasoconstriction responses were stronger in PD compared to MSA during forehead cooling (p = 0.044) and microdialysis of physiologically concentrated NE solutions (10–7; 10–8; p = 0.017). PD and MSA had impaired cold (PD: p < 0.01; MSA: p < 0.05) and warm detection thresholds (PD and MSA, both p < 0.05). The mechanical detection threshold was higher in PD (p < 0.01). Conversely, mechanical pain thresholds were decreased in PD and MSA (both p < 0.001), indicating mechanical hyperalgesia. Conclusion In contrast to MSA, we found evidence of peripheral adrenoreceptor hypersensitivity in PD, probably caused by peripheral sympathetic denervation. Sensory testing revealed peripheral neuropathy and central pain sensitization in PD and MSA. Jointly, our data demonstrate autonomic and somatosensory dysfunction in PD and MSA.

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