scholarly journals Linking Electrical Stimulation of Human Primary Visual Cortex, Size of Affected Cortical Area, Neuronal Responses, and Subjective Experience

Neuron ◽  
2016 ◽  
Vol 92 (6) ◽  
pp. 1213-1219 ◽  
Author(s):  
Jonathan Winawer ◽  
Josef Parvizi
Keyword(s):  
Electrical Stimulation ◽  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Cortical Area ◽  
Subjective Experience ◽  
Neuronal Responses ◽  
Stimulation Of

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.

scholarly journals Electrical Stimulation of the Human Visual Cortex Preliminary Report

1974 ◽  
Vol 1 (4) ◽  
pp. 236-238 ◽  
Author(s):  
Andrew Talalla ◽  
Leo Bullara ◽  
Robert Pudenz
Keyword(s):  
Electrical Stimulation ◽  
Visual Cortex ◽  
Feasibility Study ◽  
Preliminary Report ◽  
Visual Prosthesis ◽  
Human Visual Cortex ◽  
Stimulation Of

SUMMARY:A feasibility study for the development of a human visual prosthesis has led several workers to observe the effects of electrical stimulation of the human visual cortex. Experience with such stimulations of three normal-sighted patients is reported. The results confirm some of the findings of other workers, but do not show that multiple phosphenes were experienced by our patients, using strictly limited parameters of stimulation.

scholarly journals Bottom-up saliency and top-down learning in the primary visual cortex of monkeys

2018 ◽  
Vol 115 (41) ◽  
pp. 10499-10504 ◽  
Author(s):  
Yin Yan ◽  
Li Zhaoping ◽  
Wu Li
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Detection Task ◽  
Late Response ◽  
Late Component ◽  
Neuronal Responses ◽  
Top Down ◽  
Bottom Up ◽  
Response Component ◽  
Orientation Contrast

Early sensory cortex is better known for representing sensory inputs but less for the effect of its responses on behavior. Here we explore the behavioral correlates of neuronal responses in primary visual cortex (V1) in a task to detect a uniquely oriented bar—the orientation singleton—in a background of uniformly oriented bars. This singleton is salient or inconspicuous when the orientation contrast between the singleton and background bars is sufficiently large or small, respectively. Using implanted microelectrodes, we measured V1 activities while monkeys were trained to quickly saccade to the singleton. A neuron’s responses to the singleton within its receptive field had an early and a late component, both increased with the orientation contrast. The early component started from the outset of neuronal responses; it remained unchanged before and after training on the singleton detection. The late component started ∼40 ms after the early one; it emerged and evolved with practicing the detection task. Training increased the behavioral accuracy and speed of singleton detection and increased the amount of information in the late response component about a singleton’s presence or absence. Furthermore, for a given singleton, faster detection performance was associated with higher V1 responses; training increased this behavioral–neural correlate in the early V1 responses but decreased it in the late V1 responses. Therefore, V1’s early responses are directly linked with behavior and represent the bottom-up saliency signals. Learning strengthens this link, likely serving as the basis for making the detection task more reflexive and less top-down driven.

Influences from laryngeal afferents on expiratory bulbospinal neurons and motoneurons

1988 ◽  
Vol 64 (4) ◽  
pp. 1337-1345 ◽  
Author(s):  
J. S. Jodkowski ◽  
A. J. Berger
Keyword(s):  
Electrical Stimulation ◽  
Cold Water ◽  
Superior Laryngeal Nerve ◽  
Intercostal Nerve ◽  
Firing Frequency ◽  
Neuronal Responses ◽  
Water Infusion ◽  
Afferent Activation ◽  
Expiratory Neurons ◽  
Stimulation Of

The purpose of this study is to analyze the reflex effects of laryngeal afferent activation on respiratory patterns in anesthetized, vagotomized, paralyzed, ventilated cats. We recorded simultaneously from the phrenic nerve, T10 internal intercostal nerve, and single bulbospinal expiratory neurons of the caudal ventral respiratory group (VRG). Laryngeal afferents were activated by electrical stimulation of the superior laryngeal nerve (SLN) or by cold-water infusion into the larynx. Both types of stimuli caused inhibition of phrenic activity and facilitation of internal intercostal nerve activity, indicating expiratory effort. The activity of 46 bulbospinal expiratory cells was depressed during SLN electrical stimulation, and 13 of them were completely inhibited. In 44 of 56 neurons tested, mean firing frequency (FFmean) was decreased in response to cold-water infusion and 8 others responded with increased FFmean; in the remaining 4 neurons, FFmean was unchanged. Possible reasons for different neuronal responses to SLN electrical stimulation and water infusion are discussed. We conclude that bulbospinal expiratory neurons of VRG were not the source of the reflex motoneuronal expiratory-like activity produced by SLN stimulation. Other, not yet identified inputs to spinal expiratory motoneurons are activated during this experimental condition.

scholarly journals The Mystery of Louis Verrey (1854-1916)

Gesnerus ◽  
1993 ◽  
Vol 50 (1-2) ◽  
pp. 96-112
Author(s):  
Semir Zeki
Keyword(s):  
Visual Cortex ◽  
Human Brain ◽  
Primary Visual Cortex ◽  
Cortical Area ◽  
Functional Specialization ◽  
Colour Centre ◽  
Monkey Brain ◽  
Experimental Discovery ◽  
Separate Area

In 1888, Louis Verrey, a Swiss ophthalmologist, stated emphatically that there is a "centre for the chromatic sense" in the human brain and that it is located in the lingual and fusiform gyri. He did not, however, consider the “colour centre” to be a separate area but a large sub-division of the primary visual cortex. His evidence was quickly dismissed and forgotten. It was not to be taken seriously again until after the experimental discovery of functional specialization in the monkey brain. This paper considers why it is that Verrey did not consider the “colour centre” to be a separate cortical area, distinct from the primary visual cortex, why his evidence was so quickly and effectively dismissed, and why it is that Verrey did not pursue the logic of his findings.

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