scholarly journals Inter-Collicular Suppression Compresses All Types of Rate-Amplitude Functions of Inferior Collicular Neurons in Mice

2016 ◽  
pp. 527-536
Author(s):  
L. CHENG ◽  
H.-X. MEI ◽  
Y. HUANG
Keyword(s):  
Signal Processing ◽  
Dynamic Range ◽  
High Amplitude ◽  
Sound Signal ◽  
Sound Processing ◽  
Inferior Collicular ◽  
Inferior Colliculi ◽  
High Sound ◽  
Amplitude Level ◽  
Stimulation Of

The two inferior colliculi (IC) are paired structures in the midbrain that are connected to each other by a bundle of commissural fibers. The fibers play an important role in coordinating sound signal processing between the two inferior colliculi. This study examined inter-collicular suppression on sound signal processing in amplitude domain of mice by measuring the rate-amplitude functions (RAFs) of neurons in one IC during the electrical stimulation of the opposite IC. Three types (monotonic, saturated and non-monotonic) RAFs of collicular neurons were measured before and during inter-collicular suppression. Inter-collicular suppression significantly increased the slope, decreased the dynamic range and narrowed down the responsive amplitude of all RAFs to high amplitude level but did not change the type of most (36/43, 84 %) RAFs. As a result, all types of RAFs were compressed at a greater degree at low than at high sound amplitude during inter-collicular suppression. These data indicate that inter-collicular suppression improve sound processing in the high amplitude domain.

Influence of the Acoustic Reflex on Vowel Recognition

1986 ◽  
Vol 29 (3) ◽  
pp. 420-424 ◽  
Author(s):  
Michael Dorman ◽  
Ingrid Cedar ◽  
Maureen Hannley ◽  
Marjorie Leek ◽  
Julie Mapes Lindholm
Keyword(s):  
Auditory System ◽  
Sound Pressure ◽  
Dynamic Range ◽  
Recognition Accuracy ◽  
Pressure Level ◽  
Acoustic Reflex ◽  
The Poor ◽  
Stapedial Reflex ◽  
Vowel Recognition ◽  
High Sound

Computer synthesized vowels of 50- and 300-ms duration were presented to normal-hearing listeners at a moderate and high sound pressure level (SPL). Presentation at the high SPL resulted in poor recognition accuracy for vowels of a duration (50 ms) shorter than the latency of the acoustic stapedial reflex. Presentation level had no effect on recognition accuracy for vowels of sufficient duration (300 ms) to elicit the reflex. The poor recognition accuracy for the brief, high intensity vowels was significantly improved when the reflex was preactivated. These results demonstrate the importance of the acoustic reflex in extending the dynamic range of the auditory system for speech recognition.

High Dynamic Range (HDR) Signal Processing on Software-Defined Radio

2020 ◽  
Author(s):  
Phillip V. Do ◽  
Jesse Hernandez ◽  
Zhao Lu ◽  
Danson Evan Garcia ◽  
Steve Mann
Keyword(s):  
Signal Processing ◽  
Software Defined Radio ◽  
Dynamic Range ◽  
High Dynamic Range ◽  
High Dynamic

A High-Performance Signal Processing System for Monopulse Tracking Radar

2011 ◽  
Vol 383-390 ◽  
pp. 471-475
Author(s):  
Yong Bin Hong ◽  
Cheng Fa Xu ◽  
Mei Guo Gao ◽  
Li Zhi Zhao
Keyword(s):  
Signal Processing ◽  
High Performance ◽  
Dynamic Range ◽  
Signal To Noise Ratio ◽  
Processing System ◽  
Digital Signal ◽  
Radar Signal ◽  
Signal Processing System ◽  
Parallel Pipelined ◽  
Tracking Radar

A radar signal processing system characterizing high instantaneous dynamic range and low system latency is designed based on a specifically developed signal processing platform. Instantaneous dynamic range loss is a critical problem when digital signal processing is performed on fixed-point FPGAs. In this paper, the problem is well resolved by increasing the wordlength according to signal-to-noise ratio (SNR) gain of the algorithms through the data path. The distinctive software structure featuring parallel pipelined processing and “data flow drive” reduces the system latency to one coherent processing interval (CPI), which significantly improves the maximum tracking angular velocity of the monopulse tracking radar. Additionally, some important electronic counter-countermeasures (ECCM) are incorporated into this signal processing system.

Electronmicroscopic and electrophysiological studies of the teat branch of the XIII thoracic nerve: relationship with lactation in the rat

1988 ◽  
Vol 118 (3) ◽  
pp. 471-483 ◽  
Author(s):  
L. M. Voloschin ◽  
E. Décima ◽  
J. H. Tramezzani
Keyword(s):  
Electrical Stimulation ◽  
Conduction Velocity ◽  
Action Potentials ◽  
Silent Period ◽  
High Amplitude ◽  
Milk Ejection ◽  
Nerve Activity ◽  
Thoracic Nerve ◽  
Myelinated Fibres ◽  
Stimulation Of

ABSTRACT Electrical stimulation of the XIII thoracic nerve (the 'mammary nerve') causes milk ejection and the release of prolactin and other hormones. We have analysed the route of the suckling stimulus at the level of different subgroups of fibres of the teat branch of the XIII thoracic nerve (TBTN), which innervates the nipple and surrounding skin, and assessed the micromorphology of the TBTN in relation to lactation. There were 844 ± 63 and 868 ± 141 (s.e.m.) nerve fibres in the TBTN (85% non-myelinated) in virgin and lactating rats respectively. Non-myelinated fibres were enlarged in lactating rats; the modal value being 0·3–0·4 μm2 for virgin and 0·4–0·5 μm2 for lactating rats (P > 0·001; Kolmogorov–Smirnov test). The modal value for myelinated fibres was 3–6 μm2 in both groups. The compound action potential of the TBTN in response to electrical stimulation showed two early volleys produced by the Aα- and Aδ-subgroups of myelinated fibres (conduction velocity rate of 60 and 14 m/s respectively), and a late third volley originated in non-myelinated fibres ('C') group; conduction velocity rate 1·4 m/s). Before milk ejection the suckling pups caused 'double bursts' of fibre activity in the Aδ fibres of the TBTN. Each 'double burst' consisted of low amplitude action potentials and comprised two multiple discharges (33–37 ms each) separated by a silent period of around 35 ms. The 'double bursts' occurred at a frequency of 3–4/s, were triggered by the stimulation of the nipple and were related to fast cheek movements visible only by watching the pups closely. In contrast, the Aα fibres of the TBTN showed brief bursts of high amplitude potentials before milk ejection. These were triggered by the stimulation of cutaneous receptors during gross slow sucking motions of the pup (jaw movements). Immediately before the triggering of milk ejection the mother was always asleep and a low nerve activity was recorded in the TBTN at this time. When reflex milk ejection occurred, the mother woke and a brisk increase in nerve activity was detected; this decreased when milk ejection was accomplished. In conscious rats the double-burst type of discharges in Aδ fibres was not observed, possibly because this activity cannot be detected by the recording methods currently employed in conscious animals. During milk ejection, action potentials of high amplitude were conveyed in the Aα fibres of the TBTN. During the treading time of the stretch reaction (SR), a brisk increase in activity occurred in larger fibres; during the stretching periods of the SR a burst-type discharge was again observed in slow-conducting afferents; when the pups changed nipple an abrupt increase in activity occurred in larger fibres. In summary, the non-myelinated fibres of the TBTN are increased in diameter during lactation, and the pattern of suckling-evoked nerve activity in myelinated fibres showed that (a) the double burst of Aδ fibres, produced by individual sucks before milk ejection, could be one of the conditions required for the triggering of the reflex, and (b) the nerve activity displayed during milk-ejection action may result, at least in part, from 'non-specific' stimulation of cutaneous receptors. J. Endocr. (1988) 118, 471–483

scholarly journals Speech Function Following Deep Brain Stimulation of the Caudal Zona Incerta: Effects of Habitual and High-Amplitude Stimulation

2021 ◽  
pp. 1-13
Author(s):  
Linda Sandström ◽  
Ellika Schalling ◽  
Fredrik Karlsson ◽  
Patric Blomstedt ◽  
Lena Hartelius
Keyword(s):  
Deep Brain Stimulation ◽  
Brain Stimulation ◽  
High Amplitude ◽  
Nonparametric Tests ◽  
Zona Incerta ◽  
Maximal Amplitude ◽  
Significant Group ◽  
Preliminary Study ◽  
Deep Brain ◽  
Stimulation Of

Purpose Deep brain stimulation (DBS) is often successful in alleviating motor symptoms of essential tremor (ET); however, DBS may also induce adverse speech effects. The caudal zona incerta (cZi) is a promising DBS target for tremor, but less is known about the consequences of cZi DBS for speech. This preliminary study examined how habitual cZi DBS and cZi stimulation at high amplitudes may affect speech function in persons with ET. Method Fourteen participants with ET were evaluated: off stimulation, on habitual cZi DBS, and with unilateral cZi stimulation at increasing stimulation amplitudes. At each stimulation condition, the participants read three 16-word sentences. Two speech-language pathologists made audio-perceptual consensus ratings of overall speech function, articulation, and voice using a visual sort and rate method. Rated functions when off stimulation, on habitual cZi DBS, and at maximal-amplitude stimulation were compared using Friedman nonparametric tests. For participants with bilateral habitual DBS ( n = 5), the effects of bilateral and unilateral stimulation were described in qualitative terms. Results Habitual cZi DBS had no significant group-level effect on any of the investigated speech parameters. Maximal-amplitude stimulation had a small but significant negative effect on articulation. Participants with reduced articulatory precision ( n = 9) had more medially placed electrodes than the nonaffected group ( n = 5). Bilateral and unilateral left stimulation had comparable effects on speech. Conclusions Findings from this preliminary study of cZi DBS indicate that speech is generally not affected by stimulation at habitual levels. High-amplitude cZi stimulation may, however, induce adverse effects, particularly on articulation. Instances of decreased articulatory function were associated with stimulation of more medial electrode contacts, which could suggest cerebello-rubrospinal involvement.

Evaluation of Automatic Directional Processing with Cochlear Implant Recipients

2021 ◽  
Vol 32 (08) ◽  
pp. 478-486
Author(s):  
Lisa G. Potts ◽  
Soo Jang ◽  
Cory L. Hillis
Keyword(s):  
Signal Processing ◽  
Speech Recognition ◽  
Cochlear Implant ◽  
Mixed Model ◽  
Dynamic Range ◽  
Individual Variability ◽  
Noise Performance ◽  
Mixed Model Analysis ◽  
Speech In Noise ◽  
Speech Recognition In Noise

Abstract Background For cochlear implant (CI) recipients, speech recognition in noise is consistently poorer compared with recognition in quiet. Directional processing improves performance in noise and can be automatically activated based on acoustic scene analysis. The use of adaptive directionality with CI recipients is new and has not been investigated thoroughly, especially utilizing the recipients' preferred everyday signal processing, dynamic range, and/or noise reduction. Purpose This study utilized CI recipients' preferred everyday signal processing to evaluate four directional microphone options in a noisy environment to determine which option provides the best speech recognition in noise. A greater understanding of automatic directionality could ultimately improve CI recipients' speech-in-noise performance and better guide clinicians in programming. Study Sample Twenty-six unilateral and seven bilateral CI recipients with a mean age of 66 years and approximately 4 years of CI experience were included. Data Collection and Analysis Speech-in-noise performance was measured using eight loudspeakers in a 360-degree array with HINT sentences presented in restaurant noise. Four directional options were evaluated (automatic [SCAN], adaptive [Beam], fixed [Zoom], and Omni-directional) with participants' everyday use signal processing options active. A mixed-model analysis of variance (ANOVA) and pairwise comparisons were performed. Results Automatic directionality (SCAN) resulted in the best speech-in-noise performance, although not significantly better than Beam. Omni-directional performance was significantly poorer compared with the three other directional options. A varied number of participants performed their best with each of the four-directional options, with 16 performing best with automatic directionality. The majority of participants did not perform best with their everyday directional option. Conclusion The individual variability seen in this study suggests that CI recipients try with different directional options to find their ideal program. However, based on a CI recipient's motivation to try different programs, automatic directionality is an appropriate everyday processing option.

Primate nucleus gracilis neurons: responses to innocuous and noxious stimuli

1988 ◽  
Vol 59 (3) ◽  
pp. 886-907 ◽  
Author(s):  
D. G. Ferrington ◽  
J. W. Downie ◽  
W. D. Willis
Keyword(s):  
Conduction Velocity ◽  
Dynamic Range ◽  
Subcutaneous Tissue ◽  
Receptive Fields ◽  
High Threshold ◽  
Spinothalamic Tract ◽  
Sinusoidal Vibration ◽  
Nucleus Gracilis ◽  
Pressure Sensitive ◽  
Stimulation Of

1. Recordings were made from 67 neurons in the nucleus gracilis (NG) of anesthetized macaque monkeys. All of the cells were activated antidromically from the ventral posterior lateral (VPL) nucleus of the contralateral thalamus. Stimuli used to activate the cells orthodromically were graded innocuous and noxious mechanical stimuli, including sinusoidal vibration and thermal pulses. 2. The latencies of antidromic action potentials following stimulation in the VPL nucleus were significantly shorter for cells in the caudal compared with the rostral NG. The mean minimum afferent conduction velocity of the afferent conduction velocity of the afferent fibers exciting the NG cells was 52 m/s, as judged from the latencies of the cells to orthodromic volleys evoked by electrical stimulation of peripheral nerves. The overall conduction velocity of the pathway from peripheral nerve to thalamus was approximately 40 m/s. 3. Cutaneous receptive fields on the distal hindlimb usually occupied an area equivalent to much less than a single digit. However, a few cells had receptive fields up to or exceeding the area of the foot. 4. NG cells were classified by their responses to graded mechanical stimulation of the skin as low threshold (LT) or wide dynamic range (WDR). No high-threshold NG cells were found. A special subcategory of pressure-sensitive LT (SA) neurons was recognized. Many of these cells were maximally responsive to maintained indentation of the skin. The sample of NG cells differed from the population of primate spinothalamic and spinocervicothalamic pathways so far examined, in having a larger proportion of LT neurons and a smaller proportion of WDR cells. A few NG cells responded best to manipulation of subcutaneous tissue. 5. Discriminant analysis permitted the NG cells to be assigned to classes determined by a k-means cluster analysis of the responses of a reference set of 318 primate spinothalamic tract (STT) cells. There were four classes of cells based on normalized responses of individual neurons and another four classes based upon responses compared across the population of cells. The NG cells were allocated to the various categories in different proportions than either primate STT cells or spinocervicothalamic neurons, consistent with the view that the functional roles of these somatosensory pathways differ. 6. Some of the pressure-sensitive NG cells were excited when the skin was stretched, suggesting an input from type II slowly adapting (Ruffini) mechanoreceptors.(ABSTRACT TRUNCATED AT 400 WORDS)

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