scholarly journals Does the saccade-related burst in the superior colliculus convey commands related to the future location of a moving target ?

2016 ◽  
Vol 16 (12) ◽  
pp. 98 ◽  
Author(s):  
Laurent Goffart ◽  
Aaron Cecala ◽  
Neeraj Gandhi
Keyword(s):  
Superior Colliculus ◽  
Moving Target ◽  
The Future

scholarly journals The superior colliculus and the steering of saccades toward a moving visual target

2017 ◽  
Author(s):  
Laurent Goffart ◽  
Aaron Cecala ◽  
Neeraj Gandhi
Keyword(s):  
Superior Colliculus ◽  
Firing Rate ◽  
Target Location ◽  
Residual Activity ◽  
Target Motion ◽  
Moving Target ◽  
Average Firing Rate ◽  
Active Population ◽  
The Future ◽  
Movement Field

ABSTRACTFollowing the suggestion that a command encoding the expected here-and-now target location feeds the oculomotor system during interceptive saccades, we tested whether this command originates in the deep superior colliculus (SC). Monkeys generated saccades to targets that were static or moving along the preferred axis, away from (outward) or toward a fixated target (inward) with a constant speed (20°/s). Vertical and horizontal motions were also tested. Extracellular activity of 57 saccade-related neurons was recorded in 3 monkeys. The movement field (MF) parameters (boundaries, center and firing rate) were estimated after spline fitting the relation between the saccade amplitude and the average firing rate of the motor burst. During radial motion, the inner MF boundary shifted in the same direction as the target motion for some neurons, not all. During vertical motion, both lower and upper boundaries were shifted upward during upward motion whereas the upper boundary only shifted during downward motions. For horizontal motions, the medial boundaries were not changed. The MF center was shifted only for outward motion. Regardless of the motion direction, the average firing rate was consistently reduced during interceptive saccades. Our study shows an involvement of the saccade-related burst of SC neurons in steering the gaze toward a moving target. When observed, the shifts of MF boundary in the direction of target motion correspond to commands related to antecedent target locations. The absence of shift in the opposite direction shows that SC activity does not issue predictive commands related to the future target location.SIGNIFICANCE STATEMENTBy comparing the movement field (MF) of saccade-related neurons between saccades toward static and moving targets, we show that the motor burst issued by neurons in the superior colliculus does not convey commands related to the future location of a moving target. During interceptive saccades, the active population consists of a continuum of neurons, ranging from cells exhibiting a shift in the center or boundary of their MF to cells which exhibit no change. The shifts correspond to residual activity related to the fact that the active population does not change as fast as the target in the visual field. By contrast, the absence of shift indicates commands related to the current target location, as if it were static.

scholarly journals The influence of temporal predictability on express visuomotor responses

2020 ◽  
Author(s):  
Samuele Contemori ◽  
Gerald E. Loeb ◽  
Brian D. Corneil ◽  
Guy Wallis ◽  
Timothy J. Carroll
Keyword(s):  
Superior Colliculus ◽  
Onset Time ◽  
Surface Emg ◽  
Stimulus Onset ◽  
Target Motion ◽  
Target Velocity ◽  
Moving Target ◽  
Visuomotor Transformations ◽  
Shoulder Muscles ◽  
Temporal Predictability

ABSTRACTVolitional visuomotor responses in humans are generally thought to manifest 100ms or more after stimulus onset. Under appropriate conditions, however, much faster target-directed responses can be produced at upper limb and neck muscles. These “express” responses have been termed stimulus-locked responses (SLRs) and are proposed to be modulated by visuomotor transformations performed subcortically via the superior colliculus. Unfortunately, for those interested in studying SLRs, these responses have proven difficult to detect consistently across individuals. The recent report of an effective paradigm for generating SLRs in 100% of participants appears to change this. The task required the interception of a moving target that emerged from behind a barrier at a time consistent with the target velocity. Here we aimed to reproduce the efficacy of this paradigm for eliciting SLRs and to test the hypothesis that its effectiveness derives from the predictability of target onset time as opposed to target motion per se. In one experiment, we recorded surface EMG from shoulder muscles as participants made reaches to intercept temporally predictable or unpredictable targets. Consistent with our hypothesis, predictably timed targets produced more frequent and stronger SLRs than unpredictably timed targets. In a second experiment, we compared different temporally predictable stimuli and observed that transiently presented targets produced larger and earlier SLRs than sustained moving targets. Our results suggest that target motion is not critical for facilitating the expression of an SLR and that timing predictability does not rely on extrapolation of a physically plausible motion trajectory. These findings provide support for a mechanism whereby an internal timer, probably located in cerebral cortex, primes the processing of both visual input and motor output within the superior colliculus to produce SLRs.

Predicting the Future Position of a Moving Target

Perception ◽  
1991 ◽  
Vol 20 (1) ◽  
pp. 5-16 ◽  
Author(s):  
Carolyn Peterken ◽  
Brian Brown ◽  
Ken Bowman
Keyword(s):  
Moving Target ◽  
The Future ◽  
Future Position

scholarly journals The superior colliculus and the steering of saccades toward a moving visual target

2017 ◽  
Vol 118 (5) ◽  
pp. 2890-2901 ◽  
Author(s):  
Laurent Goffart ◽  
Aaron L. Cecala ◽  
Neeraj J. Gandhi
Keyword(s):  
Superior Colliculus ◽  
Firing Rate ◽  
Target Location ◽  
Oculomotor System ◽  
Moving Target ◽  
Motion Direction ◽  
Active Population ◽  
Spline Fitting ◽  
Current Location ◽  
Consistent Change

Following the suggestion that a command encoding current target location feeds the oculomotor system during interceptive saccades, we tested the involvement of the deep superior colliculus (dSC). Extracellular activity of 52 saccade-related neurons was recorded in three monkeys while they generated saccades to targets that were static or moving along the preferred axis, away from (outward) or toward (inward) a fixated target with a constant speed (20°/s). Vertical and horizontal motions were tested when possible. Movement field (MF) parameters (boundaries, preferred vector, and firing rate) were estimated after spline fitting of the relation between the average firing rate during the motor burst and saccade amplitude. During radial target motions, the inner MF boundary shifted in the motion direction for some, but not all, neurons. Likewise, for some neurons, the lower boundaries were shifted upward during upward motions and the upper boundaries downward during downward motions. No consistent change was observed during horizontal motions. For some neurons, the preferred vectors were also shifted in the motion direction for outward, upward, and “toward the midline” target motions. The shifts of boundary and preferred vector were not correlated. The burst firing rate was consistently reduced during interceptive saccades. Our study demonstrates an involvement of dSC neurons in steering the interceptive saccade. When observed, the shifts of boundary in the direction of target motion correspond to commands related to past target locations. The absence of shift in the opposite direction implies that dSC activity does not issue predictive commands related to future target location. NEW & NOTEWORTHY The deep superior colliculus is involved in steering the saccade toward the current location of a moving target. During interceptive saccades, the active population consists of a continuum of cells ranging from neurons issuing commands related to past locations of the target to neurons issuing commands related to its current location. The motor burst of collicular neurons does not contain commands related to the future location of a moving target.

The Future of Platform Power: Solving for a Moving Target

2021 ◽  
Vol 32 (3) ◽  
pp. 173-177
Author(s):  
Francis Fukuyama
Keyword(s):  
Moving Target ◽  
The Future

scholarly journals On Moving Target Techniques for Network Defense Security

2021 ◽  
Vol 9 (5) ◽  
pp. 84-90
Author(s):  
Shouq Mohsen Alnemari ◽  
Sabah M Alzahrani
Keyword(s):  
Defense Mechanisms ◽  
Assessment Methods ◽  
Moving Target ◽  
Moving Target Defense ◽  
Network Defense ◽  
Success Ratio ◽  
The Future ◽  
Traditional Technologies ◽  
Comprehensive Study

The traditional technologies, tools and procedures of any network cannot be protected from attackers due to the unchanged services and configurations of the networks. To get rid of the asymmetrical feature, Moving Target Defense technique constantly changes the platform conformation which reduces success ratio of the cyberattack. Users are faced with realness with the increase of continual, progressive, and smart attacks. However, the defenders often follow the attackers in taking suitable action to frustrate expected attackers. The moving target defense idea appeared as a preemptive protect mechanism aimed at preventing attacks. This paper conducts a comprehensive study to cover the following aspects of moving target defense, characteristics of target attacks and its limitation, classifications of defense types, major methodologies, promising defense solutions, assessment methods and applications of defense. Finally, we conclude the study and the future concern proposals. The purpose of the study is to give general directions of research regarding critical features of defense techniques to scholars seeking to improve proactive and adaptive moving target defense mechanisms.

Introduction

Outsiders ◽  
2019 ◽  
pp. 1-8
Author(s):  
Zachary Kramer
Keyword(s):  
Civil Rights ◽  
Moving Target ◽  
The World ◽  
The Future ◽  
The Times

Everyone is different in some way. Each of us has a part of our identity that, if revealed, would mark us as outsiders. These differences matter, as they define who we are and how we relate to the world around us. Because equality is a moving target, civil rights law needs to change with the times. Though we live in an age of individuality, difference can be a uniting force. As we look to the future, the charge of civil rights is to carve space for people to define who they are for themselves. We are all outsiders. We need a civil rights for everyone.

Introduction: Regulation—the Field and the Developing Agenda

2010 ◽  
pp. 2-16 ◽  
Author(s):  
Robert Baldwin ◽  
Martin Cave ◽  
Martin Lodge
Keyword(s):  
Social Life ◽  
Economic Life ◽  
Theory And Practice ◽  
Moving Target ◽  
Direct Control ◽  
Language Practice ◽  
The Past ◽  
The Future ◽  
Continuous Interaction

This text seeks to highlight the growing importance of the language, practice, and study of regulation for contemporary social life, to show how the theory and practice of regulation have developed through a process of continuous interaction, to explore key themes in the study and practice of regulation, to assess developments, and to suggest how these trajectories will develop in the future. The challenge for this book is not only to account for this broadening and maturation of interest, but also to illustrate how regulation has remained a moving target, both in the fields of practice and study, for the past three decades. The very concept of regulation has evolved so that study in this area is no longer confined to the examination of dedicated ‘command’ regimes that are designed to offer continuing and direct control over an area of economic life.

The future is a moving target

1977 ◽  
Vol 5 (5) ◽  
pp. 23-31
Author(s):  
Milton Leontiades
Keyword(s):  
Moving Target ◽  
The Future
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