scholarly journals Biosonar spatial resolution along the distance axis: revisiting the clutter interference zone

2020 ◽  
Author(s):  
Peter A. Wagenhäuser ◽  
Lutz Wiegrebe ◽  
A. Leonie Baier
Keyword(s):  
Time Delay ◽  
Auditory Cortex ◽  
Spatial Resolution ◽  
Absolute Distance ◽  
Cortical Cells ◽  
Distance Information ◽  
Object Distance ◽  
Reference Distance ◽  
Summary Statement ◽  
Phyllostomus Discolor

AbstractUnlike all other remote senses like vision or hearing, echolocation allows estimating the distance of an object. Not only have echolocating bats and toothed whales been shown to measure distance by echolocation extremely precisely, distance information is even topographically represented by a neuro-computational map in bats’ auditory cortex. This topographic representation and the corresponding tuning of cortical cells to object distance suggests the bats may be able to perceptually resolve multiple, simultaneously present objects along the distance axis. Here we use a novel psychophysical paradigm with complex phantom targets to quantity spatial resolution along the distance axis in the echolocating bat Phyllostomus discolor. We show that our bats can indeed perceptually resolve objects along the distance axis when they are separated by about 40 cm (around a reference distance of 108 cm) along the distance axis. These results are well comparable to earlier work on bats’ clutter interference zone (Simmons et al., 1988) and confirm those results with a more robust psychophysical paradigm.Summary statementEcholocating bats perceive absolute distance to objects by measuring the time delay between call and echo. In addition, they possess spatial resolution along the distance axis.

The Binocular Measuring System Research Based on OpenCV

2011 ◽  
Vol 341-342 ◽  
pp. 898-901
Author(s):  
De Jun Li ◽  
Xiao Hui Ma
Keyword(s):  
Machine Vision ◽  
Measuring System ◽  
System Research ◽  
Distance Information ◽  
Vision Development ◽  
Object Distance ◽  
Automobile Body ◽  
Pillar Industry ◽  
Vision Function ◽  
Development Step

Along with the economical development, the automobile enhances unceasingly in our country's inventory. The automobile profession takes the national support the pillar industry, has the very big promoter action to national economy's development. In recent years, the independent road sense's research and the application in domestic and foreign developed rapidly, was honored as the automobile profession the next technological revolution. This topic basis independent road sense's demand, studied one kind to be possible to use in independent driving the range measuring system. This system take the binocular range finder as a principle, may supply around the automobile body the object distance information, the precise periphery object distance information is the independent road sense foundation, thus this topic research results have the broad application space. Carries on regarding the binocular range finder's analysis under the OpenCV environment, OpenCV takes one kind to open the source the machine vision function storehouse, in the last few years along with the edition renewal, the function strengthened gradually, has involved machine vision nearly all domains. The research on two-sided visual in the OpenCV environment, simplified the binocular vision development step, sped up the development progress.

scholarly journals Processing of fast amplitude modulations in bat auditory cortex matches communication call-specific sound features

2019 ◽  
Vol 121 (4) ◽  
pp. 1501-1512 ◽  
Author(s):  
Stephen Gareth Hörpel ◽  
Uwe Firzlaff
Keyword(s):  
Auditory Cortex ◽  
Cortical Neurons ◽  
Transfer Functions ◽  
Modulation Transfer ◽  
Modulation Transfer Functions ◽  
Communication Calls ◽  
Species Specific ◽  
Frequency Modulations ◽  
Phyllostomus Discolor ◽  
Sound Features

Bats use a large repertoire of calls for social communication. In the bat Phyllostomus discolor, social communication calls are often characterized by sinusoidal amplitude and frequency modulations with modulation frequencies in the range of 100–130 Hz. However, peaks in mammalian auditory cortical modulation transfer functions are typically limited to modulation frequencies below 100 Hz. We investigated the coding of sinusoidally amplitude modulated sounds in auditory cortical neurons in P. discolor by constructing rate and temporal modulation transfer functions. Neuronal responses to playbacks of various communication calls were additionally recorded and compared with the neurons’ responses to sinusoidally amplitude-modulated sounds. Cortical neurons in the posterior dorsal field of the auditory cortex were tuned to unusually high modulation frequencies: rate modulation transfer functions often peaked around 130 Hz (median: 87 Hz), and the median of the highest modulation frequency that evoked significant phase-locking was also 130 Hz. Both values are much higher than reported from the auditory cortex of other mammals, with more than 51% of the units preferring modulation frequencies exceeding 100 Hz. Conspicuously, the fast modulations preferred by the neurons match the fast amplitude and frequency modulations of prosocial, and mostly of aggressive, communication calls in P. discolor. We suggest that the preference for fast amplitude modulations in the P. discolor dorsal auditory cortex serves to reliably encode the fast modulations seen in their communication calls. NEW & NOTEWORTHY Neural processing of temporal sound features is crucial for the analysis of communication calls. In bats, these calls are often characterized by fast temporal envelope modulations. Because auditory cortex neurons typically encode only low modulation frequencies, it is unclear how species-specific vocalizations are cortically processed. We show that auditory cortex neurons in the bat Phyllostomus discolor encode fast temporal envelope modulations. This property improves response specificity to communication calls and thus might support species-specific communication.

Noradrenergic Induction of Selective Plasticity in the Frequency Tuning of Auditory Cortex Neurons

2004 ◽  
Vol 92 (3) ◽  
pp. 1445-1463 ◽  
Author(s):  
Yves Manunta ◽  
Jean-Marc Edeline
Keyword(s):  
Auditory Cortex ◽  
Cortical Neurons ◽  
Cortical Plasticity ◽  
Frequency Tuning ◽  
Tone Frequency ◽  
Cortical Cells ◽  
Tuning Curves ◽  
Alpha Receptors ◽  
Frequency Changes ◽  
Selective Effects

Neuromodulators have long been viewed as permissive factors in experience-induced cortical plasticity, both during development and in adulthood. Experiments performed over the last two decades have reported the potency of acetylcholine to promote changes in functional properties of cortical cells in the auditory, visual, and somatosensory modality. In contrast, very few attempts were made with the monoaminergic systems. The present study evaluates how repeated presentation of brief pulses of noradrenaline (NA) concomitant with presentation of a particular tone frequency changes the frequency tuning curves of auditory cortex neurons determined at 20 dB above threshold. After 100 trials of NA-tone pairing, 28% of the cells (19/67) exhibited selective tuning modifications for the frequency paired with NA. All the selective effects were obtained when the paired frequency was within 1/4 of an octave from the initial best frequency. For these cells, selective decreases were prominent (15/19 cases), and these effects lasted ≥15 min after pairing. No selective effects were observed under various control conditions: tone alone ( n = 10 cells), NA alone ( n = 11 cells), pairing with ascorbic acid ( n = 6 cells), or with GABA ( n = 20 cells). Selective effects were observed when the NA-tone pairing was performed in the presence of propranolol (4/10 cells) but not when it was performed in the presence phentolamine (0/13 cells), suggesting that the effects were mediated by alpha receptors. These results indicate that brief increases in noradrenaline concentration can trigger selective modifications in the tuning curves of cortical neurons that, in most of the cases, go in opposite direction compared with those usually reported with acetylcholine.

Localization of a Time-Delayed, Monocular Virtual Object Superimposed on a Real Environment

2000 ◽  
Vol 9 (1) ◽  
pp. 15-24 ◽  
Author(s):  
Jeffrey W. McCandless ◽  
Stephen R. Ellis ◽  
Bernard D. Adelstein
Keyword(s):  
Time Delay ◽  
Time Delays ◽  
Motion Parallax ◽  
Virtual Object ◽  
Distance Information ◽  
Object Position ◽  
Real Environment ◽  
Judgment Error ◽  
Projected Position ◽  
Apparent Stability

Observers adjusted a pointer to match the depicted distance of a monocular virtual object viewed in a see-through, had-mounted display. Distance information was available through motion parallax produced as the observers rocked side to side. The apparent stability of the virtual object was impaired by a time delay between the observers' head motions and the corresponding change in the object position on the display. Localizations were made for four time delays (31 ms, 64 ms, 131 ms, and 197 ms) and three depicted distances (75 cm, 95 cm, and 113 cm). The errors in localizations increased systematically with time delay and depicted distance. A model of the results shows that the judgment error and lateral projected position of the virtual object are each linearly related to time delay.

scholarly journals Time Course of Forward Masking Tuning Curves in Cat Primary Auditory Cortex

1997 ◽  
Vol 77 (2) ◽  
pp. 923-943 ◽  
Author(s):  
Michael Brosch ◽  
Christoph E. Schreiner
Keyword(s):  
Receptive Field ◽  
Auditory Cortex ◽  
Stimulus Onset Asynchrony ◽  
Time Course ◽  
Tuning Curve ◽  
Primary Auditory Cortex ◽  
Stimulus Onset ◽  
Cortical Cells ◽  
Tuning Curves ◽  
Onset Asynchrony

Brosch, Michael and Christoph E. Schreiner. Time course of forward masking tuning curves in cat primary auditory cortex. J. Neurophysiol. 77: 923–943, 1997. Nonsimultaneous two-tone interactions were studied in the primary auditory cortex of anesthetized cats. Poststimulatory effects of pure tone bursts (masker) on the evoked activity of a fixed tone burst (probe) were investigated. The temporal interval from masker onset to probe onset (stimulus onset asynchrony), masker frequency, and intensity were parametrically varied. For all of the 53 single units and 58 multiple-unit clusters, the neural activity of the probe signal was either inhibited, facilitated, and/or delayed by a limited set of masker stimuli. The stimulus range from which forward inhibition of the probe was induced typically was centered at and had approximately the size of the neuron's excitatory receptive field. This “masking tuning curve” was usually V shaped, i.e., the frequency range of inhibiting masker stimuli increased with the masker intensity. Forward inhibition was induced at the shortest stimulus onset asynchrony between masker and probe. With longer stimulus onset asynchronies, the frequency range of inhibiting maskers gradually became smaller. Recovery from forward inhibition occurred first at the lower- and higher-frequency borders of the masking tuning curve and lasted the longest for frequencies close to the neuron's characteristic frequency. The maximal duration of forward inhibition was measured as the longest period over which reduction of probe responses was observed. It was in the range of 53–430 ms, with an average of 143 ± 71 (SD) ms. Amount, duration and type of forward inhibition were weakly but significantly correlated with “static” neural receptive field properties like characteristic frequency, bandwidth, and latency. For the majority of neurons, the minimal inhibitory masker intensity increased when the stimulus onset asynchrony became longer. In most cases the highest masker intensities induced the longest forward inhibition. A significant number of neurons, however, exhibited longest periods of inhibition after maskers of intermediate intensity. The results show that the ability of cortical cells to respond with an excitatory activity depends on the temporal stimulus context. Neurons can follow higher repetition rates of stimulus sequences when successive stimuli differ in their spectral content. The differential sensitivity to temporal sound sequences within the receptive field of cortical cells as well as across different cells could contribute to the neural processing of temporally structured stimuli like speech and animal vocalizations.

A New System of High-Precision Absolute Laser Interferometer Distance Measurement

2013 ◽  
Vol 380-384 ◽  
pp. 769-772
Author(s):  
Chen Yang Zhang ◽  
Bing Li
Keyword(s):  
High Precision ◽  
Laser Scanning ◽  
Laser Interferometer ◽  
Laser Interferometry ◽  
Distance Measurement ◽  
Absolute Distance ◽  
Distance Information ◽  
New Methods ◽  
Interference Fringes ◽  
New System

With the improvement of precision in various fields, we present a new method for the measurement of the absolute distance of a remote target based on the laser interferometry technique. In this paper, we obtain the interference fringes change information (the distance information) with the help of laser scanning with different frequency. It does not require the target to move in the direction of measurement. We have done experiments to compare this new methods results with the results of RENISHAW interferometer. Its improved that the accuracy of distance measurement is 10-4~10-5 relatively.

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