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.

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.

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.

scholarly journals Normal correspondence of tectal maps for saccadic eye movements in strabismus

2016 ◽  
Vol 116 (6) ◽  
pp. 2541-2549 ◽  
Author(s):  
John R. Economides ◽  
Daniel L. Adams ◽  
Jonathan C. Horton
Keyword(s):  
Electrical Stimulation ◽  
Eye Movements ◽  
Superior Colliculus ◽  
Saccadic Eye Movements ◽  
Systematic Change ◽  
Free Viewing ◽  
Pattern Deviation ◽  
Ocular Deviation ◽  
The Right ◽  
Stem Structure

The superior colliculus is a major brain stem structure for the production of saccadic eye movements. Electrical stimulation at any given point in the motor map generates saccades of defined amplitude and direction. It is unknown how this saccade map is affected by strabismus. Three macaques were raised with exotropia, an outwards ocular deviation, by detaching the medial rectus tendon in each eye at age 1 mo. The animals were able to make saccades to targets with either eye and appeared to alternate fixation freely. To probe the organization of the superior colliculus, microstimulation was applied at multiple sites, with the animals either free-viewing or fixating a target. On average, microstimulation drove nearly conjugate saccades, similar in both amplitude and direction but separated by the ocular deviation. Two monkeys showed a pattern deviation, characterized by a systematic change in the relative position of the two eyes with certain changes in gaze angle. These animals' saccades were slightly different for the right eye and left eye in their amplitude or direction. The differences were consistent with the animals' underlying pattern deviation, measured during static fixation and smooth pursuit. The tectal map for saccade generation appears to be normal in strabismus, but saccades may be affected by changes in the strabismic deviation that occur with different gaze angles.

scholarly journals Laminar Variation in Threshold for Detection of Electrical Excitation of Striate Cortex by Macaques

2005 ◽  
Vol 94 (5) ◽  
pp. 3443-3450 ◽  
Author(s):  
Edgar A. DeYoe ◽  
Jeffrey D. Lewine ◽  
Robert W. Doty
Keyword(s):  
Electrical Stimulation ◽  
Striate Cortex ◽  
Human Subjects ◽  
Human Case ◽  
Constant Current ◽  
Electrical Excitation ◽  
Detection Thresholds ◽  
Current Pulses ◽  
A Site ◽  
Stimulation Of

Macaques were trained to signal their detection of electrical stimulation applied by a movable microelectrode to perifoveal striate cortex. Trains of ≤100 cathodal, 0.2-ms, constant current pulses were delivered at 50 or 100 Hz. The minimum current that could be reliably detected was measured at successive depths along radial electrode penetrations through the cortex. The lowest detection thresholds were routinely encountered when the stimulation was applied to layer 3, particularly just at the juncture between layers 3 and 4A. On the average, there was a twofold variation in threshold along the penetrations, with the highest intracortical thresholds being in layers 4C and 6. Variations as high as 20-fold were obtained in some individual penetrations, whereas relatively little change was observed in others. The minimum detectable current was 1 μA at a site in layer 3, i.e., 10–100 times lower than that for surface stimulation. Because macaques, as do human subjects, find electrical stimulation of striate cortex to be highly similar at all loci (a phosphene in the human case), it is puzzling as to how such uniformity of effect evolves from the exceedingly intricate circuitry available to the effective stimuli. It is hypothesized that the stimulus captures the most excitable elements, which then suppress other functional moieties, producing only the luminance of the phosphene. Lowest thresholds presumably are encountered when the electrode lies among these excitable elements that can, with higher currents, be stimulated directly from some distance or indirectly by the horizontal bands of myelinated axons, the stria of Baillarger.

scholarly journals Doing Without Learning: Stimulation of the Frontal Eye Fields and Floccular Complex Does Not Instruct Motor Learning in Smooth Pursuit Eye Movements

2008 ◽  
Vol 100 (3) ◽  
pp. 1320-1331 ◽  
Author(s):  
Hilary W. Heuer ◽  
Stefanie Tokiyama ◽  
Stephen G. Lisberger
Keyword(s):  
Electrical Stimulation ◽  
Eye Movements ◽  
Motor Learning ◽  
Visual Image ◽  
Image Motion ◽  
Frontal Eye Fields ◽  
Electrical Microstimulation ◽  
Pursuit Eye Movements ◽  
Time Period ◽  
Fixed Times

Under natural conditions, motor learning is instructed by sensory feedback. We have asked whether sensory signals that indicate motor errors are necessary to instruct learning or if the motor signals related to movements normally driven by sensory error signals would be sufficient. We measured eye movements in trained rhesus monkeys while employing electrical microstimulation of the floccular complex of the cerebellum and the smooth eye movement region of the frontal eye fields to alter ongoing pursuit eye movements. Repeated electrical stimulation at fixed times after the onset of target motion and pursuit failed to cause any learning that was retained beyond the time period used to instruct learning. Learning was not uncovered when the target was stabilized with respect to the moving eye to prevent competition between instructive signals created by electrical stimulation and visual image motion signals evoked when stimulation drove the eye away from the tracking target. We suggest that signals emanating from motor-related structures in the pursuit circuit do not instruct learning. Instead, instructive sensory error signals seem to be necessary.

scholarly journals Vestibular implantation and longitudinal electrical stimulation of the semicircular canal afferents in human subjects

2015 ◽  
Vol 113 (10) ◽  
pp. 3866-3892 ◽  
Author(s):  
James O. Phillips ◽  
Leo Ling ◽  
Kaibao Nie ◽  
Elyse Jameyson ◽  
Christopher M. Phillips ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Eye Movements ◽  
Human Subjects ◽  
Vestibular Function ◽  
Slow Phase ◽  
Vestibular Loss ◽  
Stimulation Current ◽  
Eye Velocity ◽  
Over Time ◽  
Stimulation Of

Animal experiments and limited data in humans suggest that electrical stimulation of the vestibular end organs could be used to treat loss of vestibular function. In this paper we demonstrate that canal-specific two-dimensionally (2D) measured eye velocities are elicited from intermittent brief 2 s biphasic pulse electrical stimulation in four human subjects implanted with a vestibular prosthesis. The 2D measured direction of the slow phase eye movements changed with the canal stimulated. Increasing pulse current over a 0–400 μA range typically produced a monotonic increase in slow phase eye velocity. The responses decremented or in some cases fluctuated over time in most implanted canals but could be partially restored by changing the return path of the stimulation current. Implantation of the device in Meniere's patients produced hearing and vestibular loss in the implanted ear. Electrical stimulation was well tolerated, producing no sensation of pain, nausea, or auditory percept with stimulation that elicited robust eye movements. There were changes in slow phase eye velocity with current and over time, and changes in electrically evoked compound action potentials produced by stimulation and recorded with the implanted device. Perceived rotation in subjects was consistent with the slow phase eye movements in direction and scaled with stimulation current in magnitude. These results suggest that electrical stimulation of the vestibular end organ in human subjects provided controlled vestibular inputs over time, but in Meniere's patients this apparently came at the cost of hearing and vestibular function in the implanted ear.

Analysis of Saccadic Eye Movements Using an Infrared Video System in Human Subjects

1991 ◽  
Vol 111 (sup481) ◽  
pp. 382-387 ◽  
Author(s):  
Takeshi Kubo ◽  
Takanori Saika ◽  
Yoshiharu Sakata ◽  
Yasuhiro Morita ◽  
Toru Matsunaga ◽  
...  
Keyword(s):  
Eye Movements ◽  
Human Subjects ◽  
Saccadic Eye Movements ◽  
Video System ◽  
Infrared Video

Effects of caudate microstimulation on spontaneous and purposive saccades

2013 ◽  
Vol 110 (2) ◽  
pp. 334-343 ◽  
Author(s):  
Masayuki Watanabe ◽  
Douglas P. Munoz
Keyword(s):  
Electrical Stimulation ◽  
Eye Movements ◽  
Basal Ganglia ◽  
Saccadic Eye Movements ◽  
Task Demands ◽  
Behavioral Symptoms ◽  
Intrinsic Signals ◽  
Clinical Disorders ◽  
Behavioral Paradigm ◽  
The Impact

Electrical stimulation has been delivered to the basal ganglia (BG) to treat intractable symptoms of a variety of clinical disorders. However, it is still unknown how such treatments improve behavioral symptoms. A difficulty of this problem is that artificial signals created by electrical stimulation interact with intrinsic signals before influencing behavior, thereby making it important to understand how such interactions between artificial and intrinsic signals occur. We addressed this issue by analyzing the effects of electrical stimulation under the following two behavioral conditions that induce different states of intrinsic signals: 1) subjects behave spontaneously without task demands; and 2) subjects perform a behavioral paradigm purposefully. We analyzed saccadic eye movements in monkeys while delivering microstimulation to the head and body of the caudate nucleus, a major input stage of the oculomotor BG. When monkeys generated spontaneous saccades, caudate microstimulation biased saccade vector endpoints toward the contralateral direction of stimulation sites. However, when caudate microstimulation was delivered during a purposive prosaccade (look toward a visual stimulus) or an antisaccade (look away from a stimulus) paradigm, it created overall ipsilateral biases by suppressing contralateral saccades more strongly than ipsilateral saccades. These results suggest that the impact of BG electrical stimulation changes dynamically depending on the state of intrinsic signals that vary under a variety of behavioral demands in everyday life.

Suppression of Task-Related Saccades by Electrical Stimulation in the Primate's Frontal Eye Field

1997 ◽  
Vol 77 (5) ◽  
pp. 2252-2267 ◽  
Author(s):  
Douglas D. Burman ◽  
Charles J. Bruce
Keyword(s):  
Electrical Stimulation ◽  
Eye Movements ◽  
Frontal Lobe ◽  
Premotor Cortex ◽  
Saccadic Eye Movements ◽  
Association Cortex ◽  
Frontal Eye Field ◽  
Visually Guided ◽  
Low Intensity ◽  
Eye Field

Burman, Douglas D. and Charles J. Bruce. Suppression of task-related saccades by electrical stimulation in the primate's frontal eye field. J. Neurophysiol. 77: 2252–2267, 1997. Patients with frontal lobe damage have difficulty suppressing reflexive saccades to salient visual stimuli, indicating that frontal lobe neocortex helps to suppress saccades as well as to produce them. In the present study, a role for the frontal eye field (FEF) in suppressing saccades was demonstrated in macaque monkeys by application of intracortical microstimulation during the performance of a visually guided saccade task, a memory prosaccade task, and a memory antisaccade task. A train of low-intensity (20–50 μA) electrical pulses was applied simultaneously with the disappearance of a central fixation target, which was always the cue to initiate a saccade. Trials with and without stimulation were compared, and significantly longer saccade latencies on stimulation trials were considered evidence of suppression. Low-intensity stimulation suppressed task-related saccades at 30 of 77 sites tested. In many cases saccades were suppressed throughout the microstimulation period (usually 450 ms) and then executed shortly after the train ended. Memory-guided saccades were most dramatically suppressed and were often rendered hypometric, whereas visually guided saccades were less severely suppressed by stimulation. At 18 FEF sites, the suppression of saccades was the only observable effect of electrical stimulation. Contraversive saccades were usually more strongly suppressed than ipsiversive ones, and cells recorded at such purely suppressive sites commonly had either foveal receptive fields or postsaccadic responses. At 12 other FEF sites at which saccadic eye movements were elicited at low thresholds, task-related saccades whose vectors differed from that of the electrically elicited saccade were suppressed by electrical stimulation. Such suppression at saccade sites was observed even with currents below the threshold for eliciting saccades. Pure suppression sites tended to be located near or in the fundus, deeper in the anterior bank of the arcuate than elicited saccade sites. Stimulation in the prefrontal association cortex anterior to FEF did not suppress saccades, nor did stimulation in premotor cortex posterior to FEF. These findings indicate that the primate FEF can help orchestrate saccadic eye movements by suppressing inappropriate saccade vectors as well as by selecting, specifying, and triggering appropriate saccades. We hypothesize that saccades could be suppressed both through local FEF interactions and through FEF projections to subcortical regions involved in maintaining fixation.

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