The Speed of Auditory Low-Side Suppression

The nonlinear cochlear phenomenon of two-tone suppression is known to be very fast, but precisely how fast is unknown. We studied the timing of low-side suppression in the auditory nerve of the cat using multitone complexes as auditory stimuli. An evalution of the group delays of the responses to these complexes allowed us to measure the timing of the responses with sub-millisecond accuracy for a large number of fibers with characteristic frequencies (CFs) between 2 and 40 kHz. In particular, we measured the delays with which the same below-CF tone complexes affected the response either as an excitor (when presented alone) or as a suppressor (when combined with a CF probe). For CFs <10 kHz, we found that the delay of suppression was larger than the delay of excitation by several hundred microseconds. The difference between the delay of suppression and that of excitation decreased with increasing CF, becoming negligible for CFs >15 kHz. The results are analyzed in terms of traveling-wave delays and a purported cochlear gain control. The data suggest that suppression originates from a gain-control mechanism with an integration time in the order of two cycles of CF.

Download Full-text

Filamentary Nebulosity Surrounding M87

Symposium - International Astronomical Union ◽

10.1017/s0074180900150211 ◽

1987 ◽

Vol 117 ◽

pp. 216-217

Author(s):

S. van den Bergh ◽

C. J. Pritchet

Keyword(s):

Broad Band ◽

Integration Time ◽

The Difference ◽

Total Integration

Recently we have obtained both Hα + [NII] and broad-band red exposures of a number of galaxies with an RCA 320 × 512 CCD at the prime-focus of the 3.6 m CFH Telescope. Figure 1 shows the difference between Hα and red exposures (each with a total integration time of 60 min) of M87 = NGC4486.

Download Full-text

Data assimilation method to de-noise and de-filter particle image velocimetry data

Journal of Fluid Mechanics ◽

10.1017/jfm.2019.602 ◽

2019 ◽

Vol 877 ◽

pp. 196-213 ◽

Cited By ~ 2

Author(s):

Jurriaan J. J. Gillissen ◽

Roland Bouffanais ◽

Dick K. P. Yue

Keyword(s):

Particle Image Velocimetry ◽

Data Assimilation ◽

Particle Image ◽

Particle Image Velocimetry Data ◽

Reconstruction Error ◽

Integration Time ◽

Piv Measurement ◽

Image Velocimetry ◽

The Difference ◽

Filter Particle

We present a variational data assimilation method in order to improve the accuracy of velocity fields $\tilde{\boldsymbol{v}}$, that are measured using particle image velocimetry (PIV). The method minimises the space–time integral of the difference between the reconstruction $\boldsymbol{u}$ and $\tilde{\boldsymbol{v}}$, under the constraint, that $\boldsymbol{u}$ satisfies conservation of mass and momentum. We apply the method to synthetic velocimetry data, in a two-dimensional turbulent flow, where realistic PIV noise is generated by computationally mimicking the PIV measurement process. The method performs optimally when the assimilation integration time is of the order of the flow correlation time. We interpret these results by comparing them to one-dimensional diffusion and advection problems, for which we derive analytical expressions for the reconstruction error.

Download Full-text

Rapid Temporal Recalibration to Audiovisual Asynchrony Occurs Across the Difference in Neural Processing Speed Based on Spatial Frequency

i-Perception ◽

10.1177/2041669520966614 ◽

2020 ◽

Vol 11 (5) ◽

pp. 204166952096661

Author(s):

Yasuhiro Takeshima

Keyword(s):

Spatial Frequency ◽

Processing Speed ◽

Audiovisual Integration ◽

Auditory Stimuli ◽

Neural Processing ◽

Temporal Recalibration ◽

Synchrony Perception ◽

The Difference ◽

The One ◽

The Brain

Audiovisual integration relies on temporal synchrony between visual and auditory stimuli. The brain rapidly adapts to audiovisual asynchronous events by shifting the timing of subjective synchrony in the direction of the leading modality of the most recent event, a process called rapid temporal recalibration. This phenomenon is the flexible function of audiovisual synchrony perception. Previous studies found that neural processing speed based on spatial frequency (SF) affects the timing of subjective synchrony. This study examined the effects of SF on the rapid temporal recalibration process by discriminating whether the presentation of the visual and auditory stimuli was simultaneous. I compared the magnitudes of the recalibration effect between low and high SF visual stimuli using two techniques. First, I randomly presented each SF accompanied by a tone during one session, then in a second experiment, only a single SF was paired with the tone throughout the one session. The results indicated that rapid recalibration occurred regardless of difference in presented SF between preceding and test trials. The recalibration magnitude did not significantly differ between the SF conditions. These findings confirm that intersensory temporal process is important to produce rapid recalibration and suggest that rapid recalibration can be induced by the simultaneity judgment criterion changes attributed to the low-level temporal information of audiovisual events.

Download Full-text

Fundamental performance of a smart structural system utilizing thermal expansion for pointing

Journal of Intelligent Material Systems and Structures ◽

10.1177/1045389x17740965 ◽

2017 ◽

Vol 30 (9) ◽

pp. 1397-1408 ◽

Cited By ~ 1

Author(s):

Takeshi Shimada ◽

Kosei Ishimura ◽

Kawano Taro

Keyword(s):

Large Scale ◽

Control Mechanism ◽

Displacement Sensor ◽

Internal Displacement ◽

Structural System ◽

Element Analysis ◽

The Difference ◽

High Control ◽

Pointing Control ◽

Ball Joints

This study involved designing and developing a smart structural system for pointing control of large-scale trusses. The system consisted of a pointing control mechanism, an internal displacement-sensor, and a controller. The significant points of the system included the following: (1) artificial thermal expansions of truss members were utilized as linear actuators, (2) elastic hinges were employed instead of ball joints, and (3) the internal displacement-sensor that did not require external jigs and possessed high measuring accuracy was applied. The study involved conducting a feasibility study and an experimental demonstration. The results indicated that the pointing control mechanism produced a sufficient tilt angle to satisfy typical requirements of recent scientific satellites. Furthermore, the findings confirmed that the hysteresis of the pointing control mechanism could be kept sufficiently small due to the absence of sliding parts. The difference between the finite element analysis and the measured value corresponded to [Formula: see text] for a [Formula: see text] long truss. Additionally, the results suggested that the proposed smart structural system for pointing exhibited high control accuracy and tracking performance for a periodic motion. The root mean square error value for a circular trajectory with a radius of [Formula: see text] for a period of [Formula: see text] corresponded to [Formula: see text] for the [Formula: see text] long truss.

Download Full-text

Brainstem Frequency-following Response Recorded from One Vertical and Three Horizontal Electrode Derivations

Perceptual and Motor Skills ◽

10.2466/pms.2001.92.1.99 ◽

2001 ◽

Vol 92 (1) ◽

pp. 99-106 ◽

Cited By ~ 13

Author(s):

Gary C. Galbraith ◽

Bernadine Bagasan ◽

Jane Sulahian

Keyword(s):

Neural Activity ◽

Auditory Nerve ◽

Repeated Measure ◽

Auditory Stimuli ◽

Frequency Following Response ◽

Acoustic Nerve ◽

Measure Analysis ◽

Repeated Measure Analysis ◽

Noninvasive Assessment ◽

Correlation And Spectral Analysis

The human brainstem frequency-following response reflects neural activity to periodic auditory stimuli. Responses were simultaneously recorded from one vertically oriented and three horizontally oriented electrode derivations. Nine participants each received a total of 16,000 tone repetitions, 4,000 for each of four stimulus frequencies: 222, 266, 350, and 450 Hz. The responses were digitally filtered, quantified by correlation and spectral analysis, and statistically evaluated by repeated measure analysis of variance. While the various horizontal derivation responses did not differ from each other in latency (values tightly clustered around M = 2.60 msec), the vertical derivation response occurred significantly later ( M = 4.38 msec). The smaller latency for the horizontal responses suggests an origin within the acoustic nerve, while the larger latency for the vertical response suggests a central brainstem origin. The largest response amplitude resulted from gold “tiptrode” electrodes placed in each auditory meatus, suggesting that this electrode derivation provided the most accurate (noninvasive) assessment of short-latency events originating at the level of the auditory nerve.

Download Full-text

Accuracy of Synchrony Judgment and its Relation to the Auditory Brainstem Response: the Difference Between Pianists and Non-Pianists

Journal of Advanced Computational Intelligence and Intelligent Informatics ◽

10.20965/jaciii.2011.p0962 ◽

2011 ◽

Vol 15 (8) ◽

pp. 962-971

Author(s):

Eriko Aiba ◽

◽

Koji Kazai ◽

Takayuki Shimotomai ◽

Toshie Matsui ◽

...

Keyword(s):

Auditory Nerve ◽

Physiological Responses ◽

Auditory Brainstem ◽

Auditory Brainstem Responses ◽

Judgment Accuracy ◽

Synchrony Judgment ◽

Significant Difference ◽

Brainstem Response ◽

The Difference ◽

Onset Asynchrony

Synchrony judgment is one of the most important abilities for musicians. Only a few milliseconds of onset asynchrony result in a significant difference in musical expression. Using behavioural responses and Auditory Brainstem Responses (ABR), this study investigates whether synchrony judgment accuracy improves with training and, if so, whether physiological responses are also changed through training. Psychoacoustic experiments showed that accuracy of synchrony judgment of pianists was higher than that of non-pianists, implying that pianists’ ability to perceive tones increased through training. ABRmeasurements also showed differences between pianists and non-pianists. However, cochlear delay, an asymmetric aspect of temporal processing in the human auditory system, did not change with training. It is possible that training improved ability related to temporal tone perception and that training may increase synchrony in auditory nerve firing.

Download Full-text