Processing of interaural phase differences in components of harmonic and mistuned complexes in the inferior colliculus of the Mongolian gerbil

2018 ◽  
Vol 47 (10) ◽  
pp. 1242-1251 ◽  
Author(s):  
Lena Eipert ◽  
Astrid Klinge-Strahl ◽  
Georg M. Klump
Keyword(s):  
Inferior Colliculus ◽  
Mongolian Gerbil ◽  
Interaural Phase ◽  
Phase Differences

Response of auditory units in the barn owl's inferior colliculus to continuously varying interaural phase differences

1992 ◽  
Vol 67 (6) ◽  
pp. 1428-1436 ◽  
Author(s):  
A. Moiseff ◽  
T. Haresign
Keyword(s):  
Inferior Colliculus ◽  
Interaural Time Difference ◽  
Stimulus Onset ◽  
Central Nucleus ◽  
Intensity Difference ◽  
Phase Sensitivity ◽  
Tyto Alba ◽  
Interaural Phase ◽  
Stimulus Generation ◽  
Phase Differences

1. We studied the response of single units in the central nucleus of the inferior colliculus (ICc) of the barn owl (Tyto alba) to continuously varying interaural phase differences (IPDs) and static IPDs. Interaural phase was varied in two ways: continuously, by delivering tones to each ear that varied by a few hertz (binaural beat, Fig. 1), and discretely, by delaying in fixed steps the phase of sound delivered to one ear relative to the other (static phase). Static presentations were repeated at several IPDs to characterize interaural phase sensitivity. 2. Units sensitive to IPDs responded to the binaural beat stimulus over a broad range of delta f(Fig. 4). We selected a 3-Hz delta f for most of our comparative measurements on the basis of constraints imposed by our stimulus generation system and because it allowed us to reduce the influence of responses to stimulus onset and offset (Fig. 3A). 3. Characteristic interaural time or phase sensitivity obtained by the use of the binaural beat stimulus were comparable with those obtained by the use of the static technique (Fig. 5; r2 = 0.93, Fig. 6). 4. The binaural beat stimulus facilitated the measurement of characteristic delay (CD) and characteristic phase (CP) of auditory units. We demonstrated that units in the owl's inferior colliculus (IC) include those that are maximally excited by specific IPDs (CP = 0 or 1.0) as well as those that are maximally suppressed by specific IPDs (CP = 0.5; Figs. 7 and 8). 5. The selectivity of units sensitive to IPD or interaural time difference (ITD) were weakly influenced by interaural intensity difference (IID).(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of interaural time delays of noise stimuli on low-frequency cells in the cat's inferior colliculus. I. Responses to wideband noise

1986 ◽  
Vol 55 (2) ◽  
pp. 280-300 ◽  
Author(s):  
T. C. Yin ◽  
J. C. Chan ◽  
D. R. Irvine
Keyword(s):  
Inferior Colliculus ◽  
Discharge Rate ◽  
Low Frequency ◽  
Central Peak ◽  
Stimulus Level ◽  
Central Nucleus ◽  
Interaural Phase ◽  
Wideband Noise ◽  
Pure Tones ◽  
Phase Differences

We examined the responses of low-frequency neurons in the central nucleus of the inferior colliculus (ICC) of the cat to interaurally delayed, wideband noise stimuli. The stimuli were pseudorandom noise signals that were generated digitally with a nominal bandwidth of 60-4,000 Hz. We also compared the responses to noise with those obtained from interaural phase differences of pure tones. We studied 144 neurons with characteristic frequencies below 2.5 kHz. Eighty-five percent (85%) of these were sensitive to changes in both interaural time differences (ITDs) of noise and interaural phase differences of pure tones, only 2% were sensitive to one stimulus but not the other, and the remainder were insensitive to both stimuli. For most cells the discharge rate was modulated in an approximately cyclic fashion by changes in ITDs of the wideband noise stimuli. The maximal spike counts often occurred near zero ITD, and there was considerable variability in the nature of the cycling, though it usually disappeared for ITDs greater than +/- 4,000 microseconds. The position of the central peak was usually (65%) within the physiologically relevant range of +/- 400 microseconds, and most (80%) occurred at positive ITDs, which corresponded to delays to the ipsilateral stimulus. In general, the shapes of the responses were not affected by changes in stimulus level above threshold. As long as identical noises were delivered to both ears, the responses were not sensitive to the particular noise stimulus used. When uncorrelated noises were delivered to the two ears, there was no sensitivity to ITDs. Composite curves were computed by linear summation of the responses to ITDs of pure tones at frequencies spaced at equal intervals throughout each cell's response area. The shapes of composite curves were similar to the responses of the same cell to ITDs of wideband noise stimuli. The positions of the central peaks of these two functions were highly correlated (r = 0.91, slope = 0.97). The values of characteristic delay and characteristic phase computed from the tonal responses were found to be good indicators of the shapes of the noise delay curves. Characteristic phases (CPs) near zero were associated with noise delay curves symmetric about the central peak, CPs near 0.5 cycles with those symmetric about the trough, while CPs between 0 and 0.5 or between 0.5 and 1.0 had noise delay curves that were asymmetric with a prominent trough to the left or right, respectively, of the central peak.(ABSTRACT TRUNCATED AT 400 WORDS)

Effects of Auditory Stimulus Context on the Representation of Frequency in the Gerbil Inferior Colliculus

2001 ◽  
Vol 86 (3) ◽  
pp. 1113-1130 ◽  
Author(s):  
B. J. Malone ◽  
M. N. Semple
Keyword(s):  
Inferior Colliculus ◽  
Duty Cycle ◽  
Selective Adaptation ◽  
Stimulus Context ◽  
Effective Stimulus ◽  
Spatial Stimulus ◽  
Interaural Phase ◽  
Wide Range ◽  
Conditioned Responses ◽  
Frequency Changes

Prior studies of dynamic conditioning have focused on modulation of binaural localization cues, revealing that the responses of inferior colliculus (IC) neurons to particular values of interaural phase and level disparities depend critically on the context in which they occur. Here we show that monaural frequency transitions, which do not simulate azimuthal motion, also condition the responses of IC neurons. We characterized single-unit responses to two frequency transition stimuli: a glide stimulus comprising two tones linked by a linear frequency sweep (origin-sweep-target) and a step stimulus consisting of one tone followed immediately by another (origin-target). Using sets of glide and step stimuli converging on a common target, we constructed conditioned response functions (RFs) depicting the variability in the response to an identical stimulus as a function of the preceding origin frequency. For nearly all cells, the response to the target depended on the origin frequency, even for origins outside the excitatory frequency response area of the cell. Results from conditioned RFs based on long (2–4 s) and short (200 ms) duration step stimuli indicate that conditioning effects can be induced in the absence of the dynamic sweep, and by stimuli of relatively short duration. Because IC neurons are tuned to frequency, changes in the origin frequency often change the “effective” stimulus duty cycle. In many cases, the enhancement of the target response appeared related to the decrease in the “effective” stimulus duty cycle rather than to the prior presentation of a particular origin frequency. Although this implies that nonselective adaptive mechanisms are responsible for conditioned responses, slightly more than half of IC neurons in each paradigm responded significantly differently to targets following origins that elicited statistically indistinguishable responses. The prevailing influence of stimulus context when discharge history is controlled demonstrates that not all the mechanisms governing conditioning depend on the discharge history of the recorded neuron. Selective adaptation among the neuron's variously tuned afferents may help engender stimulus-specific conditioning. The demonstration that conditioning effects reflect sensitivity to spectral as well as spatial stimulus contrast has broad implications for the processing of a wide range of dynamic acoustic signals and sound sequences.

Physiological detection of interaural phase differences

2007 ◽  
Vol 121 (2) ◽  
pp. 1017-1027 ◽  
Author(s):  
Bernhard Ross ◽  
Kelly L. Tremblay ◽  
Terence W. Picton
Keyword(s):  
Interaural Phase ◽  
Phase Differences

Interaural Phase Disparity of Stutterers and Nonstutterers

1972 ◽  
Vol 15 (4) ◽  
pp. 771-780 ◽  
Author(s):  
Courtney Stromsta
Keyword(s):  
Control System ◽  
Phase Shift ◽  
Phase Difference ◽  
Auditory Feedback ◽  
Laryngeal Function ◽  
Interaural Phase ◽  
Frequency Criterion ◽  
Interaural Phase Difference ◽  
The Mean ◽  
Phase Differences

Stutterers and nonstutterers cancelled the auditory sensation evoked by bone-conducted sinusoidal signals. They accomplished this by appropriate phase and amplitude adjustments of simultaneously presented bilateral air-conducted signals of the same frequency. Criterion measures of interaural phase difference at the point of cancellation were obtained for seven frequencies. The mean interaural phase differences obtained by stutterers were consistently greater than those of the nonstutterers. Based on time-equivalent values of the mean interaural phase differences, the values for stutterers were approximately twice as great as for nonstutterers at 150, 300, and 1200 Hz. The mean interaural phase difference found to exist for stutterers at 150 Hz approximates the magnitude of phase shift of normally delayed air-conducted auditory feedback of speech sounds that serves to induce experimental blockage of phonation. This relationship, in view of other findings, offers credence to the idea that disturbance of laryngeal function effected by an anomalous audition-phonation control system could be a causative agent in stuttering.

scholarly journals Perception of Interaural Phase Differences With Envelope and Fine Structure Coding Strategies in Bilateral Cochlear Implant Users

2016 ◽  
Vol 20 ◽  
pp. 233121651666560 ◽  
Author(s):  
Stefan Zirn ◽  
Susan Arndt ◽  
Antje Aschendorff ◽  
Roland Laszig ◽  
Thomas Wesarg
Keyword(s):  
Fine Structure ◽  
Cochlear Implant ◽  
Interaural Phase ◽  
Coding Strategies ◽  
Bilateral Cochlear Implant ◽  
Phase Differences

scholarly journals First Spike Latency Code for Interaural Phase Difference Discrimination in the Guinea Pig Inferior Colliculus

2011 ◽  
Vol 31 (25) ◽  
pp. 9192-9204 ◽  
Author(s):  
O. Zohar ◽  
T. M. Shackleton ◽  
I. Nelken ◽  
A. R. Palmer ◽  
M. Shamir
Keyword(s):  
Guinea Pig ◽  
Inferior Colliculus ◽  
Phase Difference ◽  
Interaural Phase ◽  
Interaural Phase Difference ◽  
Spike Latency
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