The Representation of Amplitude Modulations in the Mammalian Auditory Midbrain

2008 ◽  
Vol 100 (3) ◽  
pp. 1602-1609 ◽  
Author(s):  
Bjarne Krebs ◽  
Nicholas A. Lesica ◽  
Benedikt Grothe
Keyword(s):  
Auditory System ◽  
Duty Cycle ◽  
Modulation Frequency ◽  
Acoustic Signals ◽  
Interpulse Interval ◽  
Neural Responses ◽  
Stimulus Amplitude ◽  
Auditory Midbrain ◽  
Pulse Trains ◽  
The Relationship

Temporal modulations in stimulus amplitude are essential for recognizing and categorizing behaviorally relevant acoustic signals such as speech. Despite this behavioral importance, it remains unclear how amplitude modulations (AMs) are represented in the responses of neurons at higher levels of the auditory system. Studies using stimuli with sinusoidal amplitude modulations (SAMs) have shown that the responses of many neurons are strongly tuned to modulation frequency, leading to the hypothesis that AMs are represented by their periodicity in the auditory midbrain. However, AMs in general are defined not only by their modulation frequency, but also by a number of other parameters (duration, duty cycle, etc.), which covary with modulation frequency in SAM stimuli. Thus the relationship between modulation frequency and neural responses as characterized with SAM stimuli alone is ambiguous. In this study, we characterize the representation of AMs in the gerbil inferior colliculus by analyzing neural responses to a series of pulse trains in which duration and interpulse interval are systematically varied to quantify the importance of duration, interpulse interval, duty cycle, and modulation frequency independently. We find that, although modulation frequency is indeed an important parameter for some neurons, the responses of many neurons are also strongly influenced by other AM parameters, typically duration and duty cycle. These results suggest that AMs are represented in the auditory midbrain not only by their periodicity, but by a complex combination of several important parameters.

scholarly journals The unbiased estimation of r2 between two sets of noisy neural responses

2021 ◽  
Author(s):  
Dean Pospisil ◽  
Wyeth A Bair
Keyword(s):  
Correlation Coefficient ◽  
Pearson Correlation ◽  
Unbiased Estimation ◽  
Pearson Correlation Coefficient ◽  
Neural Responses ◽  
Neural Data ◽  
Tuning Curves ◽  
The Relationship

The Pearson correlation coefficient squared, r2, is often used in the analysis of neural data to estimate the relationship between neural tuning curves. Yet this metric is biased by trial-to-trial variability: as trial-to-trial variability increases, measured correlation decreases. Major lines of research are confounded by this bias, including the study of invariance of neural tuning across conditions and the similarity of tuning across neurons. To address this, we extend the estimator, r̂2ER, developed for estimating model-to-neuron correlation to the neuron-to-neuron case. We compare the estimator to a prior method developed by Spearman, commonly used in other fields but widely overlooked in neuroscience, and find that our method has less bias. We then apply our estimator to the study of two forms of invariance and demonstrate how it avoids drastic confounds introduced by trial-to-trial variability.

scholarly journals Research on the Dual Modulation of All-Fiber Optic Current Sensor

Sensors ◽  
2022 ◽  
Vol 22 (2) ◽  
pp. 430
Author(s):  
Jianhua Wu ◽  
Xiaofeng Zhang ◽  
Liang Chen
Keyword(s):  
Duty Cycle ◽  
Modulation Frequency ◽  
Measurement Range ◽  
Optical Modulator ◽  
Current Sensor ◽  
Multiplication Factor ◽  
Pulsed Light ◽  
Frequency Multiplication ◽  
Integer Multiple ◽  
Ratio Error

Acousto-optic modulator (AOM) and electro-optical modulator (EOM) are applied to realize the all-fiber current sensor with a pulsed light source. The pulsed light is realized by amplitude modulation with AOM. The reflected interferometer current sensor is constructed by the mirror and phase modulation with EOM to improve the anti-interference ability. A correlation demodulation algorithm is applied for data processing. The influence of the modulation frequency and duty cycle of AOM on the optical system is determined by modeling and experiment. The duty cycle is the main factor affecting the normalized scale factor of the system. The modulation frequency mainly affects the output amplitude of the correlation demodulation and the system signal-to-noise ratio. The frequency multiplication factor links AOM and EOM, primarily affecting the ratio error. When the frequency multiplication factor is equal to the duty cycle of AOM and it is an integer multiple of 0.1, the ratio error of the system is less than 1.8% and the sensitivity and the resolution of AFOCS are 0.01063 mV/mA and 3 mA, respectively. The measurement range of AFOCS is from 11 mA to 196.62 A, which is excellent enough to meet the practical requirements for microcurrent measurement.

scholarly journals Features of external auditory canal anatomy

2021 ◽  
Vol 20 (1) ◽  
pp. 72-77
Author(s):  
I. A. Anikin ◽  
◽  
S. A. Eremin ◽  
A. E. Shinkareva ◽  
S. I. Sitnikov ◽  
...  
Keyword(s):  
Auditory System ◽  
Sound Wave ◽  
External Auditory Canal ◽  
Otitis Externa ◽  
External Ear ◽  
Tympanic Cavity ◽  
Ear Canal ◽  
Ear Diseases ◽  
Clinical Observations ◽  
The Relationship

The external auditory canal is not only a part of the external ear, but also an integral part of the human auditory system, which conducts and amplifies the sound wave. In the field of otosurgery, it is often the priority access to the tympanic cavity, and therefore it is necessary to clearly understand the features of its anatomy. The dimensions and anatomy of the external auditory canal are extremely variable: the length is 2–3,5 cm, the diameter ranges from 5-9 mm, it is somewhat curved in the horizontal and frontal planes and consists of a membranous cartilaginous part and a bony part, between which there is the most the bottleneck – the isthmus. The ear canal is covered with skin, the thickness and structure of which depends on the section of the ear canal. The membranous cartilaginous section contains sebaceous and sulfur glands. Studies identify several forms of the bony part of the ear canal: conical, hourglass-shaped, ovoid, reverse conical, and cylindrical. The endoscopic scale (CES) for the visibility of the tympanic membrane was also proposed for the convenience of assessment. It has been suggested that the shape of the external auditory canal is an etiological factor in chronic otitis externa. Unambiguous interpretations of the relationship between ear diseases and the shape of the external auditory canal have not yet been obtained, but modern developments tend to consider its importance in the development of ear diseases. Clinical observations show that certain anatomical forms of it may be involved in the pathogenesis of chronic inflammation, since they interfere with proper self-cleaning.

Dyscalculia in Patients with Vertigo

1990 ◽  
Vol 1 (1) ◽  
pp. 31-37
Author(s):  
John Risey ◽  
Wayne Briner
Keyword(s):  
Learning Disabilities ◽  
Cognitive Function ◽  
Auditory System ◽  
Auditory Processing ◽  
Mental Arithmetic ◽  
Central Auditory Processing ◽  
Balance Disorders ◽  
Central Origin ◽  
The Relationship

This paper reports a hitherto undescribed relationship between vertigo of central origin and dyscalculia. Subjects with vertigo skipped and displaced decades when counting backwards by two. The error is not recognized when presented visually. The subjects also display decrements in ability to do mental arithmetic and in central auditory processing. The results are discussed in light of the relationship between the central vestibular/auditory system and structures involved in higher cognitive function. The relationship between balance disorders and children with learning disabilities is also examined.

Effects of noise and cue enhancement on neural responses to speech in auditory midbrain, thalamus and cortex

2002 ◽  
Vol 169 (1-2) ◽  
pp. 97-111 ◽  
Author(s):  
Jenna Cunningham ◽  
Trent Nicol ◽  
Cynthia King ◽  
Steven G Zecker ◽  
Nina Kraus
Keyword(s):  
Neural Responses ◽  
Auditory Midbrain

scholarly journals Specific loss of neural sensitivity to interaural time difference of unmodulated noise stimuli following noise-induced hearing loss

2020 ◽  
Vol 124 (4) ◽  
pp. 1165-1182
Author(s):  
Hariprakash Haragopal ◽  
Ryan Dorkoski ◽  
Austin R. Pollard ◽  
Gareth A. Whaley ◽  
Timothy R. Wohl ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Interaural Time Difference ◽  
Acoustic Trauma ◽  
Sound Level ◽  
Broadband Noise ◽  
Neural Responses ◽  
Auditory Midbrain ◽  
Midbrain Neurons ◽  
Perceptual Abilities ◽  
Encode Time

Sensorineural hearing loss compromises perceptual abilities that arise from hearing with two ears, yet its effects on binaural aspects of neural responses are largely unknown. We found that, following severe hearing loss because of acoustic trauma, auditory midbrain neurons specifically lost the ability to encode time differences between the arrival of a broadband noise stimulus to the two ears, whereas the encoding of sound level differences between the two ears remained uncompromised.

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