scholarly journals Effects of chronic cochlear electrical stimulation after an extended period of profound deafness on primary auditory cortex organization in cats

2013 ◽  
Vol 39 (5) ◽  
pp. 811-820 ◽  
Author(s):  
James B. Fallon ◽  
Robert K. Shepherd ◽  
Dexter R. F. Irvine
Keyword(s):  
Electrical Stimulation ◽  
Auditory Cortex ◽  
Primary Auditory Cortex ◽  
Extended Period ◽  
Profound Deafness

Neuronal Responses in Cat Primary Auditory Cortex to Electrical Cochlear Stimulation: IV. Activation Pattern for Sinusoidal Stimulation

2003 ◽  
Vol 89 (6) ◽  
pp. 3190-3204 ◽  
Author(s):  
Marcia W. Raggio ◽  
Christoph E. Schreiner
Keyword(s):  
Electrical Stimulation ◽  
Auditory Cortex ◽  
Primary Auditory Cortex ◽  
High Threshold ◽  
Threshold Behavior ◽  
Activation Pattern ◽  
Short Term ◽  
Low Threshold ◽  
Response Thresholds

Patterns of threshold distributions for single-cycle sinusoidal electrical stimulation and single pulse electrical stimulation were compared in primary auditory cortex of the adult cat. Furthermore, the effects of auditory deprivation on these distributions were evaluated and compared across three groups of adult cats. Threshold distributions for single and multiple unit responses from the middle cortical layers were obtained on the ectosylvian gyrus in an acutely implanted animal; 2 wk after deafening and implantation (short-term group); and neonatally deafened animals implanted following 2–5 yr of deafness (long-term group). For all three cases, we observed similar patterns of circumscribed regions of low response thresholds in the region of primary auditory cortex (AI). A dorsal and a ventral region of low response thresholds were found separated by a narrow, anterior-posterior strip of elevated thresholds. The ventral low-threshold regions in the short-term group were cochleotopically arranged. By contrast, the dorsal region in the short-term animals and both low-threshold regions in long-term deafened animals maintained only weak cochleotopicity. Analysis of the spatial extent of the low-threshold regions revealed that the activated area for sinusoidal stimulation was smaller and more circumscribed than for pulsatile stimulation for both dorsal and ventral AI. The width of the high-threshold ridge that separated the dorsal and ventral low-threshold regions was greater for sinusoidal stimulation. Sinusoidal and pulsatile threshold behavior differed significantly for electrode configurations with low and high minimum thresholds. Differences in threshold behavior and cortical response distributions between the sinusoidal and pulsatile stimulation suggest that stimulus shape plays a significant role in the activation of cortical activity. Differences in the activation pattern for short-term and long-term deafness reflect deafness-induced reorganizational changes based on factors such as differences in excitatory and inhibitory balance that are affected by the stimulation parameters.

Stimulation-mapping of the upper human auditory pathway

1973 ◽  
Vol 38 (3) ◽  
pp. 320-325 ◽  
Author(s):  
Ronald R. Tasker ◽  
L. W. Organ
Keyword(s):  
Electrical Stimulation ◽  
Auditory Cortex ◽  
Brain Stem ◽  
Inferior Colliculus ◽  
Primary Auditory Cortex ◽  
Auditory Pathway ◽  
Association Cortex ◽  
Content Type ◽  
Medial Geniculate ◽  
Stimulation Of

✓ Auditory hallucinations were produced by electrical stimulation of the human upper brain stem during stereotaxic operations. The responses were confined to stimulation of the inferior colliculus, brachium of the inferior colliculus, medial geniculate body, and auditory radiations. Anatomical confirmation of an auditory site was obtained in one patient. The hallucination produced was a low-pitched nonspecific auditory “paresthesia” independent of the structure stimulated, the conditions of stimulation, or sonotopic factors. The effect was identical to that reported from stimulating the primary auditory cortex, and virtually all responses were contralateral. These observations have led to the following generalizations concerning electrical stimulation of the somesthetic, auditory, vestibular, and visual pathways within the human brain stem: the hallucination induced in each is the response to comparable conditions of stimulation, is nonspecific, independent of stimulation site, confined to the primary pathway concerned, chiefly contralateral, and identical to that induced by stimulating the corresponding primary auditory cortex. No sensory responses are found in the brain stem corresponding to those from the sensory association cortex.

Reorganization of the Frequency Map of the Auditory Cortex Evoked by Cortical Electrical Stimulation in the Big Brown Bat

2000 ◽  
Vol 83 (4) ◽  
pp. 1856-1863 ◽  
Author(s):  
Syed A. Chowdhury ◽  
Nobuo Suga
Keyword(s):  
Electrical Stimulation ◽  
Auditory Cortex ◽  
Cortical Neurons ◽  
Frequency Tuning ◽  
Acoustic Stimulus ◽  
Primary Auditory Cortex ◽  
Neural Representation ◽  
Tuning Curves ◽  
Big Brown Bat ◽  
Frequency Map

In a search phase of echolocation, big brown bats, Eptesicus fuscus, emit biosonar pulses at a rate of 10/s and listen to echoes. When a short acoustic stimulus was repetitively delivered at this rate, the reorganization of the frequency map of the primary auditory cortex took place at and around the neurons tuned to the frequency of the acoustic stimulus. Such reorganization became larger when the acoustic stimulus was paired with electrical stimulation of the cortical neurons tuned to the frequency of the acoustic stimulus. This reorganization was mainly due to the decrease in the best frequencies of the neurons that had best frequencies slightly higher than those of the electrically stimulated cortical neurons or the frequency of the acoustic stimulus. Neurons with best frequencies slightly lower than those of the acoustically and/or electrically stimulated neurons slightly increased their best frequencies. These changes resulted in the over-representation of repetitively delivered acoustic stimulus. Because the over-representation resulted in under-representation of other frequencies, the changes increased the contrast of the neural representation of the acoustic stimulus. Best frequency shifts for over-representation were associated with sharpening of frequency-tuning curves of 25% of the neurons studied. Because of the increases in both the contrast of neural representation and the sharpness of tuning, the over-representation of the acoustic stimulus is accompanied with an improvement of analysis of the acoustic stimulus.

Intensity Tuning of Neurons in The Primary Auditory Cortex of Albino Mouse

2013 ◽  
Vol 40 (4) ◽  
pp. 365
Author(s):  
Qiao-Zhen QI ◽  
Wen-Juan SI ◽  
Feng LUO ◽  
Xin WANG
Keyword(s):  
Auditory Cortex ◽  
Primary Auditory Cortex

Influence of Primary Auditory Cortex in the Characterization of Autism Spectrum in Young Adults using Brain Connectivity Parameters and Deep Belief Networks: An fMRI Study

2020 ◽  
Vol 16 (9) ◽  
pp. 1059-1073
Author(s):  
Vidhusha Srinivasan ◽  
N. Udayakumar ◽  
Kavitha Anandan
Keyword(s):  
Functional Connectivity ◽  
Auditory Cortex ◽  
Language Processing ◽  
Brain Connectivity ◽  
Primary Auditory Cortex ◽  
Autism Spectrum ◽  
Belief Networks ◽  
Deep Belief Networks ◽  
High Functioning ◽  
Low Functioning

Background: The spectrum of autism encompasses High Functioning Autism (HFA) and Low Functioning Autism (LFA). Brain mapping studies have revealed that autism individuals have overlaps in brain behavioural characteristics. Generally, high functioning individuals are known to exhibit higher intelligence and better language processing abilities. However, specific mechanisms associated with their functional capabilities are still under research. Objective: This work addresses the overlapping phenomenon present in autism spectrum through functional connectivity patterns along with brain connectivity parameters and distinguishes the classes using deep belief networks. Methods: The task-based functional Magnetic Resonance Images (fMRI) of both high and low functioning autistic groups were acquired from ABIDE database, for 58 low functioning against 43 high functioning individuals while they were involved in a defined language processing task. The language processing regions of the brain, along with Default Mode Network (DMN) have been considered for the analysis. The functional connectivity maps have been plotted through graph theory procedures. Brain connectivity parameters such as Granger Causality (GC) and Phase Slope Index (PSI) have been calculated for the individual groups. These parameters have been fed to Deep Belief Networks (DBN) to classify the subjects under consideration as either LFA or HFA. Results: Results showed increased functional connectivity in high functioning subjects. It was found that the additional interaction of the Primary Auditory Cortex lying in the temporal lobe, with other regions of interest complimented their enhanced connectivity. Results were validated using DBN measuring the classification accuracy of 85.85% for high functioning and 81.71% for the low functioning group. Conclusion: Since it is known that autism involves enhanced, but imbalanced components of intelligence, the reason behind the supremacy of high functioning group in language processing and region responsible for enhanced connectivity has been recognized. Therefore, this work that suggests the effect of Primary Auditory Cortex in characterizing the dominance of language processing in high functioning young adults seems to be highly significant in discriminating different groups in autism spectrum.

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