Binaural interaction in single units of the chinchilla auditory cortex

1974 ◽  
Vol 55 (S1) ◽  
pp. S52-S52
Author(s):  
D. A. Benson ◽  
D. C. Teas
Keyword(s):  
Auditory Cortex ◽  
Single Units ◽  
Binaural Interaction

Sensitivity to interaural intensity differences of neurons in primary auditory cortex of the cat. I. types of sensitivity and effects of variations in sound pressure level

1996 ◽  
Vol 75 (1) ◽  
pp. 75-96 ◽  
Author(s):  
D. R. Irvine ◽  
R. Rajan ◽  
L. M. Aitkin
Keyword(s):  
Auditory Cortex ◽  
High Frequency ◽  
Primary Auditory Cortex ◽  
Mirror Image ◽  
Sensitivity Function ◽  
Maximum Response ◽  
Binaural Interaction ◽  
Sensitivity Functions ◽  
Monaural Stimulation ◽  
Stimulation Of

1. Interaural intensity differences (IIDs) provide the major cue to the azimuthal location of high-frequency narrowband sounds. In recent studies of the azimuthal sensitivity of high-frequency neurons in the primary auditory cortex (field AI) of the cat, a number of different types of azimuthal sensitivity have been described and the azimuthal sensitivity of many neurons was found to vary as a function of changes in stimulus intensity. The extent to which the shape and the intensity dependence of the azimuthal sensitivity of AI neurons reflects features of their IID sensitivity was investigated by obtaining data on IID sensitivity from a large sample of neurons with a characteristic frequency (CF) > 5.5 kHz in AI of anesthetized cats. IID sensitivity functions were classified in a manner that facilitated comparison with previously obtained data on azimuthal sensitivity, and the effects of changes in the base intensity at which IIDs were introduced were examined. 2. IID sensitivity functions for CF tonal stimuli were obtained at one or more intensities for a total of 294 neurons, in most cases by a method of generating IIDs that kept the average binaural intensity (ABI) of the stimuli at the two ears constant. In the standard ABI range at which a function was obtained for each unit, five types of IID sensitivity were distinguished. Contra-max neurons (50% of the sample) had maximum response (a peak or a plateau) at IIDs corresponding to contralateral azimuths, whereas ipsi-max neurons (17%) had the mirror-image form of sensitivity. Near-zero-max neurons (18%) had a clearly defined maximum response (peak) in the range of +/- 10 dB IID, whereas a small group of tough neurons (2%) had a restricted range of minimal responsiveness with near-maximal responses at IIDs on either side. A final 18% of AI neurons were classified as insensitive to IIDs. The proportions of neurons exhibiting the various types of sensitivity corresponded closely to the proportions found to exhibit corresponding types of azimuthal sensitivity in a previous study. 3. There was a strong correlation between a neuron's binaural interaction characteristics and the form of its IID sensitivity function. Thus, neurons excited by monaural stimulation of only one ear but with either inhibitory, facilitatory, or mixed facilitatory-inhibitory effects of stimulation of the other ear had predominantly contra-max IID sensitivity (if contralateral monaural stimulation was excitatory) or ipsi-max sensitivity (if ipsilateral monaural stimulation was excitatory). Neurons driven weakly or not at all by monaural stimulation but facilitated binaurally almost all exhibited near-zero-max IID sensitivity. The exception to this tight association between binaural input and IID sensitivity was provided by neurons excited by monaural stimulation of either ear (EE neurons). Although EE neurons have frequently been considered to be insensitive to IIDs, our data were in agreement with two recent reports indicating that they can exhibit various forms of IID sensitivity: only 23 of 75 EE neurons were classified as insensitive and the remainder exhibited diverse types of sensitivity. 4. IID sensitivity was examined at two or more intensities (3-5 in most cases) for 84 neurons. The form of the IID sensitivity function (defined in terms of both shape and position along the IID axis) was invariant with changes in ABI for only a small proportion of IID-sensitive neurons (approximately 15% if a strict criterion of invariance was employed), and for many of these neurons the spike counts associated with a given IID varied with ABI, particularly at near-threshold levels. When the patterns of variation in the form of IID sensitivity produced by changes in ABI were classified in a manner equivalent to that used previously to classify the effects of intensity on azimuthal sensitivity, there was a close correspondence between the effects of intensity on corresponding types of azimuthal and IID sensitivity

Binaural Interaction in the Cod

1980 ◽  
Vol 85 (1) ◽  
pp. 323-332
Author(s):  
KATHLEEN HORNER ◽  
OLAV SAND ◽  
PER S. ENGER
Keyword(s):  
Phase Locking ◽  
Large Fraction ◽  
Excitatory Input ◽  
Single Units ◽  
Torus Semicircularis ◽  
Sound Stimulation ◽  
Binaural Interaction

1. Recordings were made from 93 single units in the acoustical lobes and the torus semicircularis of the cod during sound stimulation and anodal blocking of the posterior saccular nerves. 2. Most medullary sound responses were phase locked to the stimulus to some degree. The phase locking was less pronounced in the torus semicircularis, and sound stimulation sometimes caused clear inhibition of activity in this area. A large fraction of the units in both recording loci was insensitive to our sound stimuli, which acted mainly via the swimbladder. 3. Peripheral blocking caused decreased activity and inhibition of sound responses in the acoustic lobes, indicating excitatory ascending input to this region. Binaural interaction was found in 8 of 29 medullary units tested during both ipsi- and contralateral block. 4. Single-sided blocking experiments revealed both inhibitory and excitatory input to the torus semicircularis region. Binaural interaction was found in 3 of the 5 units tested during both ipsi- and contralateral block in this area.

Processing of Sound Sequences in Macaque Auditory Cortex: Response Enhancement

1999 ◽  
Vol 82 (3) ◽  
pp. 1542-1559 ◽  
Author(s):  
Michael Brosch ◽  
Andreas Schulz ◽  
Henning Scheich
Keyword(s):  
Auditory Cortex ◽  
Temporal Structure ◽  
Neural Mechanism ◽  
Stimulus Onset ◽  
Evoked Response ◽  
Single Units ◽  
Frequency Separation ◽  
Induced Response ◽  
Wide Range ◽  
Response Enhancement

It is well established that the tone-evoked response of neurons in auditory cortex can be attenuated if another tone is presented several hundred milliseconds before. The present study explores in detail a complementary phenomenon in which the tone-evoked response is enhanced by a preceding tone. Action potentials from multiunit groups and single units were recorded from primary and caudomedial auditory cortical fields in lightly anesthetized macaque monkeys. Stimuli were two suprathreshold tones of 100-ms duration, presented in succession. The frequency of the first tone and the stimulus onset asynchrony (SOA) between the two tones were varied systematically, whereas the second tone was fixed. Compared with presenting the second tone in isolation, the response to the second tone was enhanced significantly when it was preceded by the first tone. This was observed in 87 of 130 multiunit groups and in 29 of 69 single units with no obvious difference between different auditory fields. Response enhancement occurred for a wide range of SOA (110–329 ms) and for a wide range of frequencies of the first tone. Most of the first tones that enhanced the response to the second tone evoked responses themselves. The stimulus, which on average produced maximal enhancement, was a pair with a SOA of 120 ms and with a frequency separation of about one octave. The frequency/SOA combinations that induced response enhancement were mostly different from the ones that induced response attenuation. Results suggest that response enhancement, in addition to response attenuation, provides a basic neural mechanism involved in the cortical processing of the temporal structure of sounds.

Optical imaging of binaural interaction in multiple fields of the guinea pig auditory cortex

Neuroreport ◽  
2004 ◽  
Vol 15 (7) ◽  
pp. 1093-1097 ◽  
Author(s):  
Yutaka Hosokawa ◽  
Shunji Sugimoto ◽  
Michinori Kubota ◽  
Ikuo Taniguchi ◽  
Junsei Horikawa
Keyword(s):  
Guinea Pig ◽  
Auditory Cortex ◽  
Optical Imaging ◽  
Binaural Interaction

Single unit study of binaural interaction in the auditory cortex of the chinchilla

1976 ◽  
Vol 103 (2) ◽  
pp. 313-338 ◽  
Author(s):  
Dennis A. Benson ◽  
Donald C. Teas
Keyword(s):  
Auditory Cortex ◽  
Single Unit ◽  
Binaural Interaction
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