What Delay Fields Tell Us About Striate Cortex

2007 ◽  
Vol 98 (2) ◽  
pp. 559-576 ◽  
Author(s):  
Edward J. Tehovnik ◽  
Warren M. Slocum
Keyword(s):  
Striate Cortex ◽  
Visual Space ◽  
Saccadic Eye Movements ◽  
Visual Signal ◽  
Delay Effect ◽  
Electrical Microstimulation ◽  
Cortex Area ◽  
Motor Signal ◽  
The Brain ◽  
Stimulation Of

It is well known that electrical activation of striate cortex (area V1) can disrupt visual behavior. Based on this knowledge, we discovered that electrical microstimulation of V1 in macaque monkeys delays saccadic eye movements when made to visual targets located in the receptive field of the stimulated neurons. This review discusses the following issues. First, the parameters that affect the delay of saccades by microstimulation of V1 are reviewed. Second, the excitability properties of the V1 elements mediating the delay are discussed. Third, the properties that determine the size and shape of the region of visual space affected by stimulation of V1 are described. This region is called a delay field. Fourth, whether the delay effect is mainly due to a disruption of the visual signal transmitted through V1 or whether it is a disturbance of the motor signal transmitted between V1 and the brain stem saccade generator is investigated. Fifth, the properties of delay fields are used to estimate the number of elements activated directly by electrical microstimulation of macaque V1. Sixth, these properties are used to make inferences about the characteristics of visual percepts induced by such stimulation. Seventh, the disruptive effects of V1 stimulation in monkeys and humans are compared. Eighth, a cortical mechanism to account for the disruptive effects of V1 stimulation is proposed. Finally, these effects are related to normal vision.

Saccadic eye movements evoked by electrical stimulation of the cat's visual cortex

1988 ◽  
Vol 1 (1) ◽  
pp. 135-143 ◽  
Author(s):  
James T. McIlwain
Keyword(s):  
Eye Movements ◽  
Striate Cortex ◽  
Saccadic Eye Movements ◽  
Normal Response ◽  
Visual Orienting ◽  
Cortex Area ◽  
Orienting Behavior ◽  
Alert Cats ◽  
Coil Method ◽  
Stimulation Of

AbstractEye movements were recorded with the scleral search coil method while striate cortex (area 17) was stimulated in alert cats with their heads fixed. Regardless of where stimulation was applied in the retinotopic map, eye position at the onset of stimulation strongly affected the amplitudes of evoked saccades, but had much less influence on their directions. Application of long stimulus trains evoked repeated saccades at all sites tested. Highly convergent or goal-directed saccades were not observed. Cortically evoked saccades appeared to habituate with repeated stimulation and had higher thresholds and longer latencies that those reported for saccades evoked from the superior colliculus. The directions of cortically evoked saccades generally agreed with those predicted from the retinotopic coordinates of the stimulus sites, but saccade amplitudes were usually lower than expected. It is suggested that these findings are consistent with certain characteristics of eye-head coordination in the cat's normal visual orienting behavior. The results are difficult to reconcile with the hypothesis that goal-directed saccades are a normal response to targets outside the cat's oculomotor range.

scholarly journals Phosphene Induction and the Generation of Saccadic Eye Movements by Striate Cortex

2005 ◽  
Vol 93 (1) ◽  
pp. 1-19 ◽  
Author(s):  
E. J. Tehovnik ◽  
W. M. Slocum ◽  
C. E. Carvey ◽  
P. H. Schiller
Keyword(s):  
Electrical Stimulation ◽  
Eye Movements ◽  
Striate Cortex ◽  
Human Subjects ◽  
Saccadic Eye Movements ◽  
Visual Prosthesis ◽  
Prosthetic Device ◽  
Electrical Microstimulation ◽  
Stimulation Parameters ◽  
Cortex Area

The purpose of this review is to critically examine phosphene induction and saccadic eye movement generation by electrical microstimulation of striate cortex (area V1) in humans and monkeys. The following issues are addressed: 1) Properties of electrical stimulation as they pertain to the activation of V1 elements; 2) the induction of phosphenes in sighted and blind human subjects elicited by electrical stimulation using various stimulation parameters and electrode types; 3) the induction of phosphenes with electrical microstimulation of V1 in monkeys; 4) the generation of saccadic eye movements with electrical microstimulation of V1 in monkeys; and 5) the tasks involved for the development of a cortical visual prosthesis for the blind. In this review it is concluded that electrical microstimulation of area V1 in trained monkeys can be used to accelerate the development of an effective prosthetic device for the blind.

Review Lecture - Behavioural analysis of the monkey’s visual nervous system

1972 ◽  
Vol 182 (1069) ◽  
pp. 427-455 ◽  
Keyword(s):  
Lateral Geniculate Nucleus ◽  
Striate Cortex ◽  
Visual Space ◽  
Dorsal Lateral Geniculate Nucleus ◽  
Anterior Portion ◽  
Lateral Geniculate ◽  
Early Results ◽  
Negative Effect ◽  
Occipital Lobes ◽  
The Brain

1. Introduction Of the three million or so nerve fibres that stream into the primate brain, about two million originate in the eyes. Of these fibres, about one-and-a-half million are in the geniculo-striate system, so named because it connects the eyes with a region of the thalamus known as the dorsal lateral geniculate nucleus and that nucleus with the striate cortex (also known as area 17 or area OC, figure 1) in the occipital lobes. About half, therefore, of all the inputs to the brain are fibres of retinal origin having relatively direct and concentrated access to the cerebral cortex. One may be allowed some surprise, therefore, to find that David Ferrier claimed in 1886 that monkeys subjected to large occipital lobectomies (figures 2, 3) were unaffected by this drastic interruption of such a massive afferent channel. He said 'I removed the greater portion of both occipital lobes at the same time without causing the slightest appreciable impairment of vision. One of these animals within 2 h of the operation was able to run about freely, avoiding obstacles, to pick up such a minute object as a raisin without the slightest hesitation or want of precision, and to act in accordance with its visual experience in a perfectly normal manner’ (Ferrier 1886, p. 273). Ferrier went on to say that ‘Horseley and Schäfer inform me that their results of removal of the occipital lobes entirely harmonize with mine as to the completely negative effect of this operation’ (p. 276), which is a curious claim because two years later Schäfer was locked in a most bitter dispute with Ferrier over just this point, and their argument is merely the most extreme example of the lack of agreement about the functions of the visual cortex in animals that has persisted over the years. We now know, with the benefit of hindsight, that there may have been an uninteresting explanation of these early results of Ferrier’s, because not all of the fibres from the lateral geniculate nucleus project to the lateral surface of the brain. Some of the striate cortex ─ that part which responds to stimulation of the most peripheral parts of the retinae ─ is buried in the calcarine fissure on the medial aspect of the brain, and the most anterior portion of this may be spared even after a complete occipital lobectomy (figure 1). Were Ferrier’s animals using an intact part of their visual space?

Microstimulation of the Frontal Eye Field and Its Effects on Covert Spatial Attention

2004 ◽  
Vol 91 (1) ◽  
pp. 152-162 ◽  
Author(s):  
Tirin Moore ◽  
Mazyar Fallah
Keyword(s):  
Eye Movements ◽  
Spatial Attention ◽  
Saccadic Eye Movements ◽  
Visual Signals ◽  
Luminance Change ◽  
Target Event ◽  
Target Luminance ◽  
Electrical Microstimulation ◽  
Increased Sensitivity ◽  
Stimulation Of

Many studies have established that the strength of visual perception and the strength of visual representations within visual cortex vary according to the focus of covert spatial attention. While it is clear that attention can modulate visual signals, the source of this modulation remains unknown. We have examined the possibility that saccade related mechanisms provide a source of spatial attention by studying the effects of electrical microstimulation of the frontal eye fields (FEF) on spatial attention. Monkeys performed a task in which they had to detect luminance changes of a peripheral target while ignoring a flashing distracter. The target luminance change could be preceded by stimulation of the FEF at current levels below that which evoked saccadic eye movements. We found that when the target change was preceded by stimulation of FEF, the monkey could detect smaller changes in target luminance. The increased sensitivity to the target change only occurred when the target was placed in the part of the visual field represented by neurons at the stimulation site. The magnitude of improvement depended on the temporal asynchrony of the stimulation onset and the target event. No significant effect of stimulation was observed when long intervals (>300 ms) between stimulation and the target event were used, and the magnitude of the increased sensitivity decreased systematically with increasing asynchrony. At the shortest asynchrony, FEF stimulation temporally overlapped the target event and the magnitude of the improvement was comparable to that of removing the distracter from the task. These results demonstrate that transient, but potent improvements in the deployment of covert spatial attention can be obtained by microstimulation of FEF sites from which saccadic eye movements are also evoked.

scholarly journals Fixation Induced Blindness

2020 ◽  
Author(s):  
Ahmad Yousef
Keyword(s):  
Receptive Field ◽  
Visual Awareness ◽  
Visual Space ◽  
Saccadic Eye Movements ◽  
Retinal Photoreceptors ◽  
Invariance Hypothesis ◽  
Respective Field ◽  
The Brain ◽  
Emmert’S Law

This article reports how fixation could convey visual stimuli to the invisibility region whether the stimuli are presented centrally or peripherally regardless the textures of the background. It also reports the impossibility of conveying visual stimulus to the invisibility region when the stimulus is not fixated, namely, when the stimulus is in motion. We started in discussing how visual fixation could convey a centrally presented stimulus (pink horse) into the invisibility region under certain conditions, and why breaking the aforementioned invisibility by an intentional saccade away from the fixational point allows the stimulus to exert a ghostly horse but with complementary colours. Scientists had been hypothesizing that image aftereffect is caused by neural adaptation. In another word, the retinal photoreceptors & its corresponding neurological pathways to the visual awareness might be being idle, namely, the visual respective field might be idle. Idle visual receptive field seems to be the best explanation of the present illusion, namely, we see the light grayish background turned to greenish in the aforementioned desensitized receptive field. Important to mention, fixation greatly inhibits the spontaneous saccadic eye movements, and thus, it reduces the rooms of the receptive field remapping. Namely, every visual space will be possibly have unchangeable visual map in the brain. To arrest the aforementioned statements, we built a running stimulus to disallow the overlapping of the image and its aftereffect, and we found that the image cannot disappear. In another word, the visual awareness of the aforementioned stimulus would have ghostly & cloudy green balls in between the original materials (purple balls). The previously mentioned finding confirms the role of the spontaneous saccadic movement in promoting visibility & preventing the blindness, also see reference 1. We ended this research with asserting whether the claims against Emmert's law which raised doubts about the accurate compliance of the aforementioned law and size–distance invariance hypothesis. Weirdly enough, the claims are correct as if the image aftereffect projected against distant wall is following the dynamical visual angle but not the static one.

Compression of Visual Space before Saccades

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 100-100 ◽  
Author(s):  
D C Burr ◽  
M C Morrone ◽  
J Ross
Keyword(s):  
Eye Movements ◽  
Coordinate System ◽  
Human Visual System ◽  
Visual Space ◽  
Saccadic Eye Movements ◽  
Forced Choice ◽  
Smooth Transition ◽  
Visual Signal ◽  
Saccade Target ◽  
Apparent Position

We studied how the human visual system recalibrates visual coordinates to compensate for saccadic eye movements. Observers made 20 horizontal saccades to a target on an otherwise featureless red screen, and reported the apparent position of a vertical green bar that was briefly displayed before, during, or after the saccade. Bars presented 50 ms before the beginning of the saccade, or after its completion, were perceived accurately and veridically. However, bars presented immediately prior to the saccade were systematically mislocated, either in the direction of the saccade or in the opposite direction, depending on the spatial position of the bar. This result has been verified by various techniques including Vernier offset estimation, and a forced-choice annulling task. When four bars (straddling the saccade target) were displayed in the interval −25 to 0 ms, they were seen to be merged into 1 bar (forced choice). None of these effects could be mimicked by causing the scene to move at saccadic speeds and amplitudes. The results suggest that each saccade is accompanied by a non-visual signal that displaces the retinal coordinate system, and a momentary compression of visual space. The perceptual compression may be instrumental in ensuring a smooth transition from fixation to fixation.

Chemical Stimulation of the Brain Makes Stimulating Reading

1975 ◽  
Vol 20 (12) ◽  
pp. 923-924
Author(s):  
MADGE E. SCHEIBEL ◽  
ARNOLD B. SCHEIBEL
Keyword(s):  
Chemical Stimulation ◽  
The Brain ◽  
Stimulation Of

High Frequency Vibration of Worst Ear Lobule induced short period of Rapid Inhibition of any Cancer Activity including Advanced Terminal Cancers, Most Malignant Brain Tumor "Glioblastoma" as well as Cancer of Lung, Breast & Gastrointestinal Cancers particularly Pancreatic Cancer.

2020 ◽  
Vol 44 (3) ◽  
pp. 241-249
Author(s):  
Yoshiaki Omura
Keyword(s):  
Pancreatic Cancer ◽  
Vitamin D3 ◽  
High Frequency ◽  
Optimal Dose ◽  
High Frequency Stimulation ◽  
Frequency Stimulation ◽  
Short Time ◽  
The Brain ◽  
Cancer Activity ◽  
Stimulation Of

While a visiting Professor at the University of Paris, VI (formerly Sorvonne) more than 40 years ago, the Author became very good friends with Dr. Paul Nogier who periodically gave seminars and workshops in Paris. After the author diagnosed his cervical problem & offered him simple help, Dr. Nogier asked the Author to present lectures and demonstrations on the effects of ear stimulation, namely the effects of acupuncture & electrical stimulation of the ear lobules. It is only now, in 2019 that we have discovered 2–5 minute high frequency stimulation of the ear lobule inhibits cancer activity for 1– 4 hours post stimulation. Although the procedure is extremely simple. First take optimal dose of Vitamin D3, which has the most essential 10 unique beneficial factors required for every human cell activity. Next, apply high frequency stimulation to ear lobule while the worst ear lobule is held by all fingers with vibrator directly touching the surface of the worst ear lobule, preferably after patient repeatedly takes optimal dose of Vitamin D3. When the worst ear lobule is held between thumb & index fingers and applying mechanical stimulation of 250 ~ 500 mechanical vibration/second for 2 ~ 5 minutes using an electrical vibrator, there is rapid disappearance of cancer activity in both the brain and rest of the body for short time duration 1 ~ 4 hours. The effect often increases by additional pressure by holding fingers. As of May 2019, the Author found that many people from various regions of the world developed early stages of multiple cancers. For evaluation of this study, U. S. patented Bi-Digital O-Ring Test (BDORT) was used which was developed by the Author while doing his Graduate experimental physics research at Colombia University. BDORT was found to be most essential for determining the beneficial effects as well as harmful effects of any substance or treatment. Using BDORT, Author was the first to recognize severe increasing mid-backache was an early sign of pancreatic cancer of President of New York State Board of Medicine after top pain specialists failed to detect the cause after 3 years of effort, while the BDORT showed early stages of cancer whereas conventional X-Ray of the pancreas did not show any cancer image until 2 months after Author detected with BDORT. For example, the optimal dose of the banana is usually about 2.0 - 2.5 millimeters cross section of the banana. A whole banana is more than 50 ~ 100 times the optimal dose. Any substance eaten in more than 25 times of its optimal dose becomes highly toxic and creates DNA mutations which can cause multiple malignancies in the presence of strong electro-magnetic field. With standard medication given by doctor, patients often become sick and they are unable to reduce body weight, unless medication is reduced or completely stopped. When the amount of zinc is very high, DNA often becomes unstable and multiple cancers can grow rapidly in the presence of strong electromagnetic field. Large amount of Vitamin C from regular orange or orange juice inhibit the most important Vitamin D3 effects. At least 3 kinds of low Vitamin C oranges will not inhibit Vitamin D3. Since B12 particularly methyl cobalamin which is a red small tablet is known to improve brain circulation very significantly we examined its effect within 20 seconds of oral intake we found the following very significant changes. Acetylcholine in both sides of the brain often increases over 4,500 ng. Longevity gene Sirtuin 1 level increases significantly for short time of few hours. Thymosin α1 and Thymosinβ4 both increase to over 1500 ng from 20 ng or less.

scholarly journals A Simple Method to Avoid Brain Shift during Neuronavigation: Technical Note

2020 ◽  
Author(s):  
Jair Leopoldo Raso
Keyword(s):  
Dura Mater ◽  
Brain Area ◽  
Conventional Technique ◽  
Technical Note ◽  
Cortical Surface ◽  
Brain Shift ◽  
Simple Method ◽  
Cortex Area ◽  
Neuronavigation System ◽  
The Brain

Abstract Introduction The precise identification of anatomical structures and lesions in the brain is the main objective of neuronavigation systems. Brain shift, displacement of the brain after opening the cisterns and draining cerebrospinal fluid, is one of the limitations of such systems. Objective To describe a simple method to avoid brain shift in craniotomies for subcortical lesions. Method We used the surgical technique hereby described in five patients with subcortical neoplasms. We performed the neuronavigation-guided craniotomies with the conventional technique. After opening the dura and exposing the cortical surface, we placed two or three arachnoid anchoring sutures to the dura mater, close to the edges of the exposed cortical surface. We placed these anchoring sutures under microscopy, using a 6–0 mononylon wire. With this technique, the cortex surface was kept close to the dura mater, minimizing its displacement during the approach to the subcortical lesion. In these five cases we operated, the cortical surface remained close to the dura, anchored by the arachnoid sutures. All the lesions were located with a good correlation between the handpiece tip inserted in the desired brain area and the display on the navigation system. Conclusion Arachnoid anchoring sutures to the dura mater on the edges of the cortex area exposed by craniotomy constitute a simple method to minimize brain displacement (brain-shift) in craniotomies for subcortical injuries, optimizing the use of the neuronavigation system.

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