Acute spiral ganglion lesions change the tuning and tonotopic organization of cat inferior colliculus neurons

2000 ◽  
Vol 147 (1-2) ◽  
pp. 200-220 ◽  
Author(s):  
Russell L. Snyder ◽  
Donal G. Sinex ◽  
JoAnn D. McGee ◽  
Edward W. Walsh
Keyword(s):  
Inferior Colliculus ◽  
Spiral Ganglion ◽  
Tonotopic Organization

Inferior colliculus. II. Development of tuning characteristics and tonotopic organization in central nucleus of the neonatal cat

1975 ◽  
Vol 38 (5) ◽  
pp. 1208-1216 ◽  
Author(s):  
L. M. Aitkin ◽  
D. R. Moore
Keyword(s):  
Inferior Colliculus ◽  
Tuning Curve ◽  
External Auditory Meatus ◽  
Auditory Pathway ◽  
Central Nucleus ◽  
Synaptic Density ◽  
Tonotopic Organization ◽  
Tuning Curves ◽  
Sharp Form ◽  
Cochlear Development

Tuning curves were measured for 65 units in the inferior colliculus of seven anesthetized kittens aged from 6 to 28 days. At 2 days of age the inferior colliculus was divisible into central, pericentral, and external nuclei. Evidence was found for broader tuning curves to occur in the pericentral nucleus compared with the central nucleus, as has been observed in the adult. The middle ear was filled with serous fluid to 6 days, while the external auditory meatus remained collapsed until 10 days. Central nucleus tuning curves in kittens were relatively flat with high thresholds. Best-frequency thresholds diminished from a mean of near 100 dB SPL at 6-11 days to near 50 dB in the adult. The marked drop in thresholds between days 22 and 21 led to the adoption of the sharp form of tuning curve common for adults. Tonotopic organization of the central nucleus was clear at day 11. Speculations were advanced about the dependence of central auditory maturations on cochlear development, axon myelination in the auditory pathway, and changes in synaptic density as a function of age.

Effects of intracochlear factors on spiral ganglion cells and auditory brain stem response after long-term electrical stimulation in deafened kittens

2000 ◽  
Vol 122 (3) ◽  
pp. 425-433
Author(s):  
Eugene N. Myers ◽  
Susumu Araki ◽  
Atsushi Kawano ◽  
H. Lee Seldon ◽  
Robert K. Shepherd ◽  
...  
Keyword(s):  
Brain Stem ◽  
Inferior Colliculus ◽  
Negative Correlation ◽  
Volume Fraction ◽  
Spiral Ganglion ◽  
Organ Of Corti ◽  
Scala Tympani ◽  
Auditory Brain Stem Response ◽  
Spiral Ganglion Cell ◽  
Auditory Brain Stem

Using an animal model, we have studied the response of the auditory brain stem to cochlear implantation and the effect of intracochlear factors on this response. Neonatally, pharmacologically deafened cats (100 to more than 180 days old) were implanted with a 4-electrode array in both cochleas. Then, the left cochlea of each cat was electrically stimulated for total periods of up to 1000 hours. After a terminal 14C-2-deoxyglucose (2DG) experiment, the fraction of the right inferior colliculus with a significant accumulation of 2DG label was calculated. Using 3-dimensional computer-aided reconstruction, we examined the cochleas of these animals for spiral ganglion cell (SGC) survival and intracochlear factors such as electrode positions, degeneration of the organ of Corti, and the degree of fibrosis of the scala tympani. The distribution of each parameter was calculated along the organ of Corti from the basal end. There was a positive correlation between SGC survival and the level of fibrosis in the scala tympani, and a negative correlation between SGC survival and the degree of organ of Corti degeneration. Finally, there was a negative correlation between the 2DG-labeled inferior colliculus volume fraction and the degree of fibrosis, particularly in the 1-mm region nearest the pair of electrodes, and presumably in the basal turn.

Observations on Tonotopic Organization within the Rat Inferior Colliculus Using 2-Deoxy-D[1-3H] Glucose

1982 ◽  
Vol 90 (6) ◽  
pp. 795-800 ◽  
Author(s):  
James R. Coleman ◽  
Maurice Campbell ◽  
William J. Clerici
Keyword(s):  
Inferior Colliculus ◽  
Pure Tone ◽  
Central Nucleus ◽  
Banding Patterns ◽  
Tonotopic Organization ◽  
Marking Technique

Tonotopic organization is a major feature of central auditory structures. The tritiated 2-deoxyglucose metabolic marking technique is demonstrated to be useful for visualizing isofrequency contours in the rat inferior colliculus. Following pure-tone stimulation, the central nucleus of the inferior colliculus shows discrete, prominent banding patterns and a well-organized tonotopic arrangement.

scholarly journals A Discontinuous Tonotopic Organization in the Inferior Colliculus of the Rat

2008 ◽  
Vol 28 (18) ◽  
pp. 4767-4776 ◽  
Author(s):  
M. S. Malmierca ◽  
M. A. Izquierdo ◽  
S. Cristaudo ◽  
O. Hernandez ◽  
D. Perez-Gonzalez ◽  
...  
Keyword(s):  
Inferior Colliculus ◽  
Tonotopic Organization

Tonotopic organization in the inferior colliculus of the rat

1973 ◽  
Vol 56 ◽  
pp. 355-358 ◽  
Author(s):  
Ben M. Clopton ◽  
Jeffrey A. Winfield
Keyword(s):  
Inferior Colliculus ◽  
Tonotopic Organization

scholarly journals Anisotropic Panglial Coupling Reflects Tonotopic Organization in the Inferior Colliculus

2018 ◽  
Vol 12 ◽  
Author(s):  
Simon L. Wadle ◽  
Vanessa Augustin ◽  
Julia Langer ◽  
Ronald Jabs ◽  
Camille Philippot ◽  
...  
Keyword(s):  
Inferior Colliculus ◽  
Tonotopic Organization

scholarly journals Spatial Selectivity to Intracochlear Electrical Stimulation in the Inferior Colliculus is Degraded After Long-Term Deafness in Cats

2007 ◽  
Vol 98 (5) ◽  
pp. 2588-2603 ◽  
Author(s):  
Maike Vollmer ◽  
Ralph E. Beitel ◽  
Russell L. Snyder ◽  
Patricia A. Leake
Keyword(s):  
Electrical Stimulation ◽  
Inferior Colliculus ◽  
Dynamic Range ◽  
Spiral Ganglion ◽  
Auditory Brain Stem Response ◽  
Spatial Selectivity ◽  
Spiral Ganglion Cell ◽  
Response Thresholds ◽  
And Control

In an animal model of electrical hearing in prelingually deaf adults, this study examined the effects of deafness duration on response thresholds and spatial selectivity (i.e., cochleotopic organization, spatial tuning and dynamic range) in the central auditory system to intracochlear electrical stimulation. Electrically evoked auditory brain stem response (EABR) thresholds and neural response thresholds in the external (ICX) and central (ICC) nuclei of the inferior colliculus were estimated in cats after varying durations of neonatally induced deafness: in animals deafened <1.5 yr (short-deafened unstimulated, SDU cats) with a mean spiral ganglion cell (SGC) density of ∼45% of normal and in animals deafened >2.5 yr (long-deafened, LD cats) with severe cochlear pathology (mean SGC density <7% of normal). LD animals were subdivided into unstimulated cats and those that received chronic intracochlear electrical stimulation via a feline cochlear implant. Acutely deafened, implanted adult cats served as controls. Independent of their stimulation history, LD animals had significantly higher EABR and ICC thresholds than SDU and control animals. Moreover, the spread of electrical excitation was significantly broader and the dynamic range significantly reduced in LD animals. Despite the prolonged durations of deafness the fundamental cochleotopic organization was maintained in both the ICX and the ICC of LD animals. There was no difference between SDU and control cats in any of the response properties tested. These findings suggest that long-term auditory deprivation results in a significant and possibly irreversible degradation of response thresholds and spatial selectivity to intracochlear electrical stimulation in the auditory midbrain.

Immediate Changes in Tuning of Inferior Colliculus Neurons Following Acute Lesions of Cat Spiral Ganglion

2002 ◽  
Vol 87 (1) ◽  
pp. 434-452 ◽  
Author(s):  
Russell L. Snyder ◽  
Donal G. Sinex
Keyword(s):  
Inferior Colliculus ◽  
Spiral Ganglion ◽  
Primary Auditory Cortex ◽  
Compound Action Potential ◽  
Central Nucleus ◽  
Auditory Information ◽  
Cells Of Origin ◽  
Wide Range ◽  
Before And After ◽  
Evoked Compound Action Potential

In previous studies, we demonstrated that acute lesions the spiral ganglion (SG), the cells of origin of the auditory nerve (AN), change the frequency organization of the inferior colliculus central nucleus (ICC) and primary auditory cortex (AI). In those studies, we used a map/re-map approach and recorded the tonotopic organization of neurons before and after restricted SG lesions. In the present study, response areas (RAs) of ICC multi-neuronal clusters were recorded to contralateral and ipsilateral tones after inserting and fixing-in-place tungsten microelectrodes. RAs were recorded from most electrodes before, immediately (within 33–78 min) after, and long(several hours) after restricted mechanical lesions of the ganglion. Each SG lesion produced a “notch” in the tone-evoked compound action potential (CAP) audiogram corresponding to a narrow range of lesion frequencies with elevated thresholds. Responses of contralateral IC neurons, which responded to these lesion frequencies, underwent an elevation in threshold to the lesion frequencies with either no change in sensitivity to other frequencies or with dramatic decreases in threshold to lesion-edge frequencies. These changes in sensitivity produced shifts in characteristic frequency (CF) that could be more than an octave. Thresholds at these new CFs matched the prelesion thresholds of neurons tuned to the lesion-edge frequencies. Responses evoked by ipsilateral tones delivered to the intact ear often underwent complementary changes, i.e., decreased thresholds to lesion frequency tones with little or no change in sensitivity to other frequencies. These results indicate that responses of IC neurons are produced by convergence of auditory information across a wide range of AN fibers and that the acute “plastic” changes reported in our previous studies occur within 1 h of an SG lesion.

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