Eye position effects in saccadic adaptation in macaque monkeys

2012 ◽  
Vol 108 (10) ◽  
pp. 2819-2826 ◽  
Author(s):  
Svenja Wulff ◽  
Annalisa Bosco ◽  
Katharina Havermann ◽  
Giacomo Placenti ◽  
Patrizia Fattori ◽  
...  
Keyword(s):  
Macaca Fascicularis ◽  
Species Differences ◽  
The Other ◽  
Eye Position ◽  
Saccadic Amplitude ◽  
Position Effects ◽  
Starting Position ◽  
Saccadic Adaptation ◽  
Gaussian Profile ◽  
Position Dependence

The saccadic amplitude of humans and monkeys can be adapted using intrasaccadic target steps in the McLaughlin paradigm. It is generally believed that, as a result of a purely retinal reference frame, after adaptation of a saccade of a certain amplitude and direction, saccades of the same amplitude and direction are all adapted to the same extent, independently from the initial eye position. However, recent studies in humans have put the pure retinal coding in doubt by revealing that the initial eye position has an effect on the transfer of adaptation to saccades of different starting points. Since humans and monkeys show some species differences in adaptation, we tested the eye position dependence in monkeys. Two trained Macaca fascicularis performed reactive rightward saccades from five equally horizontally distributed starting positions. All saccades were made to targets with the same retinotopic motor vector. In each session, the saccades that started at one particular initial eye position, the adaptation position, were adapted to shorter amplitude, and the adaptation of the saccades starting at the other four positions was measured. The results show that saccades that started at the other positions were less adapted than saccades that started at the adaptation position. With increasing distance between the starting position of the test saccade and the adaptation position, the amplitude change of the test saccades decreased with a Gaussian profile. We conclude that gain-decreasing saccadic adaptation in macaques is specific to the initial eye position at which the adaptation has been induced.

Eye position effects in saccadic adaptation

2011 ◽  
Vol 106 (5) ◽  
pp. 2536-2545 ◽  
Author(s):  
Katharina Havermann ◽  
Eckart Zimmermann ◽  
Markus Lappe
Keyword(s):  
Eye Movements ◽  
Visual Space ◽  
Initial Position ◽  
Head Movements ◽  
Eye Position ◽  
Saccade Amplitude ◽  
Position Effects ◽  
Position Information ◽  
Saccadic Adaptation ◽  
Visual Error

Saccades are used by the visual system to explore visual space with the high accuracy of the fovea. The visual error after the saccade is used to adapt the control of subsequent eye movements of the same amplitude and direction in order to keep saccades accurate. Saccadic adaptation is thus specific to saccade amplitude and direction. In the present study we show that saccadic adaptation is also specific to the initial position of the eye in the orbit. This is useful, because saccades are normally accompanied by head movements and the control of combined head and eye movements depends on eye position. Many parts of the saccadic system contain eye position information. Using the intrasaccadic target step paradigm, we adaptively reduced the amplitude of reactive saccades to a suddenly appearing target at a selective position of the eyes in the orbitae and tested the resulting amplitude changes for the same saccade vector at other starting positions. For central adaptation positions the saccade amplitude reduction transferred completely to eccentric starting positions. However, for adaptation at eccentric starting positions, there was a reduced transfer to saccades from central starting positions or from eccentric starting positions in the opposite hemifield. Thus eye position information modifies the transfer of saccadic amplitude changes in the adaptation of reactive saccades. A gain field mechanism may explain the eye position dependence found.

Species differences in effect of gram-negative endotoxin on circulation

1961 ◽  
Vol 200 (6) ◽  
pp. 1197-1202 ◽  
Author(s):  
Hiroshi Kuida ◽  
Robert P. Gilbert ◽  
Lerner B. Hinshaw ◽  
Joel G. Brunson ◽  
Maurice B. Visscher
Keyword(s):  
Pulmonary Artery ◽  
Right Ventricular ◽  
Species Differences ◽  
The Other ◽  
Short Segment ◽  
Gram Negative ◽  
Microscopic Studies ◽  
Significant Mechanism ◽  
Dramatic Fall ◽  
Made In

Studies were made in 5 monkeys, 7 rabbits, and 33 cats of the effect of gram-negative endotoxin on aortic, pulmonary artery (PAP), and portal venous (PVP) pressures; and on changes in weight of a short segment of intestine. Studies of blood pooling were also made in 12 cats. The responses in these species were compared with those previously observed in the dog. Although variable degrees of hypotension developed at one time or another in all animals following injection of endotoxin, the early precipitous hypotension that characteristically occurs in the dog was observed only in the cat. However, in this species the dramatic fall in pressure could be ascribed to pulmonary vascular constriction and acute right ventricular hypertension and failure, and not to splanchnic pooling. PAP also became elevated in the monkey and the rabbit, but usually was of lesser magnitude and did not appear to explain the development of the relatively late hypotension that occurred in these species. The absence of significant increases in gut weight and the minor increments in PVP in all animals indicate that in none of these species is hepatic vein constriction and splanchnic pooling a significant mechanism in producing early shock as it is in the dog. Pathologic gross and microscopic studies in the monkey and gross examinations in the other species supported this conclusion.

Eye Position Dependence of Innervation On-directions of Motoneurons in the Monkey

1996 ◽  
Vol 781 (1 Lipids and Sy) ◽  
pp. 629-632 ◽  
Author(s):  
K. HEPP ◽  
Y. SUZUKI ◽  
D. STRAUMANN ◽  
B. J. M. HESS ◽  
V. HENN
Keyword(s):  
Eye Position ◽  
Position Dependence

Relation Between the Metrics of the Presaccadic Attention Shift and of the Saccade Before and After Saccadic Adaptation

2000 ◽  
Vol 84 (4) ◽  
pp. 1809-1813 ◽  
Author(s):  
J. Ditterich ◽  
T. Eggert ◽  
A. Straube
Keyword(s):  
Hierarchical Level ◽  
Saccade Target ◽  
Eye Position ◽  
Attention Shift ◽  
Short Term ◽  
Saccadic Adaptation ◽  
Attention Focus ◽  
Before And After ◽  
Saccade Size ◽  
Saccade Programming

A shift of the visual attention focus is known to precede saccades. However, how the metrics of both this presaccadic attention shift and the saccade are coupled is still unclear. We altered the saccade size by short-term saccadic adaptation to determine whether the attention focus would still be shifted to the location of the saccade target or to the modified postsaccadic eye position. The results showed that saccadic adaptation had no influence on the presaccadic attention shift. Thus either different processes determine the metrics of the attention shift and of the saccade or saccadic adaptation causes only modifications on a lower hierarchical level of saccade programming, thereby not influencing the metrics of the attention shift.

Differences in intersaccadic adaptation transfer between inward and outward adaptation

2011 ◽  
Vol 106 (3) ◽  
pp. 1399-1410 ◽  
Author(s):  
Fabian Schnier ◽  
Markus Lappe
Keyword(s):  
Peak Velocity ◽  
The Other ◽  
Saccade Target ◽  
Control Mechanisms ◽  
Saccadic Adaptation ◽  
Saccade Onset ◽  
Independent Parameters ◽  
Saccade Duration ◽  
Velocity Decrease

Saccadic adaptation is a mechanism to increase or decrease the amplitude gain of subsequent saccades, if a saccade is not on target. Recent research has shown that the mechanism of gain increasing, or outward adaptation, and the mechanism of gain decreasing, or inward adaptation, rely on partly different processes. We investigate how outward and inward adaptation of reactive saccades transfer to other types of saccades, namely scanning, overlap, memory-guided, and gap saccades. Previous research has shown that inward adaptation of reactive saccades transfers only partially to these other saccade types, suggesting differences in the control mechanisms between these saccade categories. We show that outward adaptation transfers stronger to scanning and overlap saccades than inward adaptation, and that the strength of transfer depends on the duration for which the saccade target is visible before saccade onset. Furthermore, we show that this transfer is mainly driven by an increase in saccade duration, which is apparent for all saccade categories. Inward adaptation, in contrast, is accompanied by a decrease in duration and in peak velocity, but only the peak velocity decrease transfers from reactive saccades to other saccade categories, i.e., saccadic duration remains constant or even increases for test saccades of the other categories. Our results, therefore, show that duration and peak velocity are independent parameters of saccadic adaptation and that they are differently involved in the transfer of adaptation between saccade categories. Furthermore, our results add evidence that inward and outward adaptation are different processes.

The Reception Process in Austria and Switzerland

2008 ◽  
Author(s):  
Daniela Thurnherr
Keyword(s):  
Human Rights ◽  
Early Stage ◽  
Case Law ◽  
Legal Order ◽  
The Other ◽  
Council Of Europe ◽  
Starting Position ◽  
European Court ◽  
The Status ◽  
The Common

This chapter discusses the reception of the ECHR in Austria and Switzerland. Topics covered include the accession and ratification of the ECHR in both countries, the status of the ECHR in national law, an overview of the activity of the European Court of Human Rights, and the ECtHR's case law and its effects on the national legal order. Although both countries joined the ECHR at a relatively early stage, this starting position led to different outcomes. The main reason is because the common denominators of neutrality and federalism in these two countries are actually rather small: as Austria follows a very different concept of neutrality, it did not face any (political) difficulties before and during the ratification process. Switzerland, on the other hand, was very reluctant to join the Council of Europe and careful to avoid any concessions with regard to neutrality.

Postsaccadic eye position contributes to oculomotor error estimation in saccadic adaptation

2019 ◽  
Vol 122 (5) ◽  
pp. 1909-1917
Author(s):  
Svenja Gremmler ◽  
Markus Lappe
Keyword(s):  
Visual Feedback ◽  
Eye Position ◽  
Time Interval ◽  
Proprioceptive Information ◽  
Experimental Conditions ◽  
Position Information ◽  
Saccadic Adaptation ◽  
Position Signal ◽  
Motor Error ◽  
Saccade Control

We investigated whether the proprioceptive eye position signal after the execution of a saccadic eye movement is used to estimate the accuracy of the movement. If so, saccadic adaptation, the mechanism that maintains saccade accuracy, could use this signal in a similar way as it uses visual feedback after the saccade. To manipulate the availability of the proprioceptive eye position signal we utilized the finding that proprioceptive eye position information builds up gradually after a saccade over a time interval comparable to typical saccade latencies. We confined the retention time of gaze at the saccade landing point by asking participants to make fast return saccades to the fixation point that preempt the usability of proprioceptive eye position signals. In five experimental conditions we measured the influence of the visual and proprioceptive feedback, together and separately, on the development of adaptation. We found that the adaptation of the previously shortened saccades in the case of visual feedback being unavailable after the saccade was significantly weaker when the use of proprioceptive eye position information was impaired by fast return saccades. We conclude that adaptation can be driven by proprioceptive eye position feedback. NEW & NOTEWORTHY We show that proprioceptive eye position information is used after a saccade to estimate motor error and adapt saccade control. Previous studies on saccadic adaptation focused on visual feedback about saccade accuracy. A multimodal error signal combining visual and proprioceptive information is likely more robust. Moreover, combining proprioceptive and visual measures of saccade performance can be helpful to keep vision, proprioception, and motor control in alignment and produce a coherent representation of space.

Visual Mental Rotation: Different Processes Used by Pilots

1992 ◽  
Vol 36 (18) ◽  
pp. 1368-1372
Author(s):  
Itiel E. Dror
Keyword(s):  
Mental Rotation ◽  
Single Step ◽  
The Other ◽  
Angular Rotation ◽  
Small Perturbations ◽  
Starting Position ◽  
Control Subjects ◽  
Complex Stimuli ◽  
And Control ◽  
Incremental Rotation

Air Force pilots and control subjects were tested on a visual “mental rotation” task. Nine of the 16 pilots, as well as all of the 16 control subjects, required more time to rotate greater angular distances. The performance of the other 7 pilots was unique: their response time did not increase with greater angular rotations. The results suggest that visual mental rotation can be accomplished by at least two different processes. One process involves incremental object rotations in a multi-step mapping –like an actual physical rotation of an object– going through intermediate stages. This process requires more time to rotate greater angular distances. The other process involves direct translation in a single-step mapping. In this process, the starting position transforms into the final position in one mapping without any intermediate steps, and thus does not require more time to rotate greater angular rotation. The lack of intermediate stages, which may allow small perturbations in location to be corrected, affects the accuracy of this process; this is particularly apparent when more complex stimuli are rotated. The pilots who did not show incremental rotation effects had different and distinct error patterns, their errors increased when rotating the more complex stimuli.

Eye Position Effects on the Neuronal Activity of Dorsal Premotor Cortex in the Macaque Monkey

1998 ◽  
Vol 80 (3) ◽  
pp. 1132-1150 ◽  
Author(s):  
Driss Boussaoud ◽  
Christophe Jouffrais ◽  
Frank Bremmer
Keyword(s):  
Reference Frame ◽  
Neuronal Activity ◽  
Premotor Cortex ◽  
Macaque Monkey ◽  
Limb Movement ◽  
Movement Direction ◽  
Eye Position ◽  
Dorsal Premotor Cortex ◽  
Position Effects ◽  
The Brain

Boussaoud, Driss, Christophe Jouffrais, and Frank Bremmer. Eye position effects on the neuronal activity of dorsal premotor cortex in the macaque monkey. J. Neurophysiol. 80: 1132–1150, 1998. Visual inputs to the brain are mapped in a retinocentric reference frame, but the motor system plans movements in a body-centered frame. This basic observation implies that the brain must transform target coordinates from one reference frame to another. Physiological studies revealed that the posterior parietal cortex may contribute a large part of such a transformation, but the question remains as to whether the premotor areas receive visual information, from the parietal cortex, readily coded in body-centered coordinates. To answer this question, we studied dorsal premotor cortex (PMd) neurons in two monkeys while they performed a conditional visuomotor task and maintained fixation at different gaze angles. Visual stimuli were presented on a video monitor, and the monkeys made limb movements on a panel of three touch pads located at the bottom of the monitor. A trial begins when the monkey puts its hand on the central pad. Then, later in the trial, a colored cue instructed a limb movement to the left touch pad if red or to the right one if green. The cues lasted for a variable delay, the instructed delay period, and their offset served as the go signal. The fixation spot was presented at the center of the screen or at one of four peripheral locations. Because the monkey's head was restrained, peripheral fixations caused a deviation of the eyes within the orbit, but for each fixation angle, the instructional cue was presented at nine locations with constant retinocentric coordinates. After the presentation of the instructional cue, 133 PMd cells displayed a phasic discharge (signal-related activity), 157 were tonically active during the instructed delay period (set-related or preparatory activity), and 104 were active after the go signal in relation to movement (movement-related activity). A large proportion of cells showed variations of the discharge rate in relation to limb movement direction, but only modest proportions were sensitive to the cue's location (signal, 43%; set, 34%; movement, 29%). More importantly, the activity of most neurons (signal, 74%; set, 79%; movement, 79%) varied significantly (analysis of variance, P < 0.05) with orbital eye position. A regression analysis showed that the neuronal activity varied linearly with eye position along the horizontal and vertical axes and can be approximated by a two-dimensional regression plane. These data provide evidence that eye position signals modulate the neuronal activity beyond sensory areas, including those involved in visually guided reaching limb movements. Further, they show that neuronal activity related to movement preparation and execution combines at least two directional parameters: arm movement direction and gaze direction in space. It is suggested that a substantial population of PMd cells codes limb movement direction in a head-centered reference frame.

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