scholarly journals Excitation of the Pre-frontal and Primary Visual Cortex in Response to Transcorneal Electrical Stimulation in Retinal Degeneration Mice

2020 ◽  
Vol 14 ◽  
Author(s):  
Stephen K. Agadagba ◽  
Xin Li ◽  
Leanne Lai Hang Chan
Keyword(s):  
Electrical Stimulation ◽  
Visual Cortex ◽  
Retinal Degeneration ◽  
Primary Visual Cortex ◽  
Transcorneal Electrical Stimulation

scholarly journals A machine-learning algorithm correctly classifies cortical evoked potentials from both natural retinal stimulation and electrical stimulation of the optic nerve

2021 ◽  
Author(s):  
Vivien Gaillet ◽  
Elodie Geneviève Zollinger ◽  
Diego Ghezzi
Keyword(s):  
Electrical Stimulation ◽  
Visual Cortex ◽  
Optic Nerve ◽  
Visual Field ◽  
Primary Visual Cortex ◽  
Nerve Stimulation ◽  
Visual Stimulation ◽  
Cortical Activity ◽  
Artificial Vision ◽  
Optic Nerve Stimulation

AbstractObjectiveOptic nerve’s intraneural stimulation is an emerging neuroprosthetic approach to provide artificial vision to totally blind patients. An open question is the possibility to evoke individual non-overlapping phosphenes via selective intraneural optic nerve stimulation. To begin answering this question, first, we aim at showing in preclinical experiments with animals that each intraneural electrode could evoke a distinguishable activity pattern in the primary visual cortex.ApproachWe performed both patterned visual stimulation and patterned electrical stimulation in healthy rabbits while recording evoked cortical activity with an electrocorticogram array in the primary visual cortex. Electrical stimulation was delivered to the optic nerve with the intraneural array OpticSELINE. We used a support vector machine algorithm paired to a linear regression model to classify cortical responses originating from visual stimuli located in different portions of the visual field and electrical stimuli from the different electrodes of the OpticSELINE.Main resultsCortical activity induced by visual and electrical stimulation could be classified with nearly 100% accuracy relative to the specific location in the visual field or electrode in the array from which it originated. For visual stimulation, the accuracy increased with the separation of the stimuli and reached 100% for separation higher than 7 degrees. For electrical stimulation, at low current amplitudes, the accuracy increased with the distance between electrodes, while at higher current amplitudes, the accuracy was nearly 100% already for the shortest separation.SignificanceOptic nerve’s intraneural stimulation with the OpticSELINE induced discernible cortical activity patterns. These results represent a leap forward for intraneural optic nerve stimulation towards artificial vision.

scholarly journals Serotonergic Modulation of Orientation Tuning of Neurons in Primary Visual Cortex of Anesthetized Mice

2021 ◽  
Author(s):  
Sareh Rostami ◽  
◽  
Amin Asgharzadeh Alvar ◽  
Parviz Ghaderi ◽  
Leila Dargahi ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Visual Cortex ◽  
Firing Rate ◽  
Primary Visual Cortex ◽  
Serotonergic System ◽  
Orientation Tuning ◽  
Visual Response ◽  
Visual Responses ◽  
Patch Clamp Recording ◽  
Serotonergic Modulation

Introduction: Sensory processing is profoundly regulated by brain neuromodulatory systems. One of the main neuromodulators is serotonin which influences higher cognitive functions such as different aspects of perceptual processing. So, malfunction in the serotonergic system may lead to visual illusion in psychiatric disorders such as autism and schizophrenia. In this work, we examined the serotonergic modulation of visual responses of neurons to stimulus orientation in the primary visual cortex. Methods: Eight-weeks old naive mice were anesthetized and craniotomy was done on the region of interest in primary visual cortex. Spontaneous and visual-evoked activities of neurons were recorded before and during the electrical stimulation of dorsal raphe nucleus using in vivo whole-cell patch-clamp recording. Square-wave grating of 12 orientations was presented. Data was analyzed and Wilcoxon signed-rank test, used in order to compare the data of two conditions that belong to the same neurons, with or without electrical stimulation. Results: The serotonergic system changed orientation tuning of about 60 % recorded neurons by decreasing the mean firing rate in two independent visual response components: gain and baseline response. It also increased mean firing rate in a small number of neurons (about 20%). Beyond that, it left the preferred orientation and sensitivity of neurons unchanged. Conclusion: However, serotonergic modulation showed a bi-directional effect; it seems to cause predominately divisive and subtractive decreases in the visual responses of the neurons in the primary visual cortex that can modify the balance between internal and external sensory signals and result in disorders.

Residual contrast response in primary visual cortex of rats with inherited retinal degeneration

2020 ◽  
Vol 177 ◽  
pp. 6-11
Author(s):  
Ke Chen ◽  
Bojun Hou ◽  
Yilei Zhao ◽  
Peimin Yuan ◽  
Dezhong Yao ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Retinal Degeneration ◽  
Primary Visual Cortex ◽  
Contrast Response ◽  
Inherited Retinal Degeneration

scholarly journals Electrophysiology Alterations in Primary Visual Cortex Neurons of Retinal Degeneration (S334ter-line-3) Rats

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Ke Chen ◽  
Yi Wang ◽  
Xiaohua Liang ◽  
Yihuai Zhang ◽  
Tsz Kin Ng ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Retinal Degeneration ◽  
Primary Visual Cortex ◽  
Visual Cortex Neurons

scholarly journals A vision prosthesis based on electrical stimulation of the primary visual cortex using epicortical microelectrodes

2020 ◽  
Author(s):  
Denise Oswalt ◽  
Projag Datta ◽  
Neil Talbot ◽  
Zaman Mirzadeh ◽  
Bradley Greger
Keyword(s):  
Electrical Stimulation ◽  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Microelectrode Array ◽  
Electrical Current ◽  
Electrical Currents ◽  
Chronic Electrical Stimulation ◽  
Multiple Array ◽  
Visual Cortical ◽  
Stimulation Of

Prostheses that can restore limited vision in the profoundly blind have been under investigation for several decades. Studies using epicortical macroelectrodes and intracortical microelectrodes have validated that electrical stimulation of primary visual cortical can serve as the basis for a vision prosthesis. However, neither of these approaches has resulted in a clinically viable vision prosthesis. Epicortical macroelectrodes required high levels of electrical current to evoke visual percepts, while intracortical microelectrodes faced challenges with longevity and stability. We hypothesized that epicortical microelectrodes could evoke visual percepts at lower currents than macroelectrodes and provide improved longevity and stability compared with intracortical microelectrodes. To test this hypotheses we implanted epicortical microelectrode arrays over the primary visual cortex of a nonhuman primate. Electrical stimulation via this array was used to evaluate the ability of epicortical microstimulation to evoke differentiable visual percepts. Visual percepts were evoked using the epicortical microelectrode array, and at electrical currents notably lower than those required to evoke visual percepts on macroelectrode arrays. The electrical current thresholds for evoking visual percepts on the epicortical microelectrode array were consistent across multiple array implants and over several months. Normal vision of light perception was not impaired by multiple array implants or chronic electrical stimulation, demonstrating that no gross visual deficit resulted from the experiments. We specifically demonstrate that epicortical microelectrode interfaces can serve as the basis for a vision prosthesis and more generally may provide an approach to evoking perception in multiple sensory modalities.

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