R J Krauzlis

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..These results suggest how SC neurons may coordinate the initiation of pursuit and saccades: buildup activity may gate the initiation of pursuit, whereas it indirectly triggers saccades by recruiting a saccade-related burst...

..In one version of this mechanism, the decision to select a new goal would occur each time the null hypothesis, represented by neurons in the rostral SC, was rejected in favor of an alternative represented elsewhere in the SC...

..These points of similarity may hold the key for understanding how neural circuits negotiate the links between the many higher order functions that can influence behavior and the singular and coordinated motor actions that follow...

..These results show that activity from the same set of neurons in the superior colliculus can predict target choices for both pursuit and saccades...

..In this issue of Neuron, Wilmer and Nakayama use a novel analysis to show that the initial changes in smooth-pursuit eye speed are driven by low-level motion signals, whereas the later eye speed is determined by high-level signals...

..These results indicate that discharge of rostral SC neurons during pursuit is not simply a visual response, but includes extraretinal signals...

..Applying cognitive factors such as expectations at relatively early stages of visual processing could act to coordinate the metrics of eye movements with perceptual judgements...

..In this issue of Neuron, Felsen and Mainen use an olfactory-guided orienting task to show that the superior colliculus is necessary in rodents for the normal execution of spatial locomotor choices...

..Thus the tonic activity of these rostral neurons provides a potential position-error signal rather than a motor command-a principle that may be applicable to buildup neurons elsewhere in the SC...

..The differences in the details of the effects on pursuit and saccades suggest that the neural mechanisms that trigger these two movements can be independently regulated...

..Although the traditional view describes pursuit and saccades as two distinct neural systems, it may be more accurate to consider the two movements as different outcomes from a shared cascade of sensory-motor functions...

..The gap paradigm did not produce "express" pursuit, even though express saccades could be elicited on interleaved trials...

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..These results provide evidence that the superior colliculus is part of the mechanism for suppressing self-generated visual signals during microsaccades that might otherwise disrupt perceptual stability...

..small. We propose that the timing of the saccade decision process depends on both the size of the attended object and the magnitude of the perturbation...

..In this issue of Neuron, present provocative data showing that microstimulation of the precentral cortex evokes complex movements, and conclude that the motor and premotor cortex together may form a single map of complex postures...

..When distracting stimuli contained no information, discrimination performance was largely unaffected. Thus, the superior colliculus is a bottleneck in the covert selection of signals for perceptual judgments...

..Spatial cues were only partly effective in directing attention to other locations in our task, and these cueing effects were biased for locations ahead of the tracked target...

..These results demonstrate that Markov chains can be used to dynamically assign probabilities that are rapidly exploited by human subjects during saccade target selection...

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..These results demonstrate the flexibility with which activity across the SC represents the location, as well as the spatial precision, of behaviorally relevant goals for multiple eye movements...

..We found that eye movements significantly promoted perceptual coherence compared to fixation. These results indicate that eye movement information constrains the perceptual interpretation of visual inputs...

..We argue that this pattern occurs because pursuit and saccades share a decision signal, but utilize different response thresholds and are subject to different motor processing delays...

..We suggest that the primacy of spatial information for both pursuit and saccades reflects the importance of spatial attention in selecting the stimulus target for both eye movements...

..Together, these results suggest that a common inhibitory mechanism regulates the initiation of pursuit and saccades...

..The inactivation-induced bias for smooth pursuit and button press responses indicates SC activity is important for selecting the target, independent of any role in saccade preparation...

..Our results demonstrate that learned contingencies can increase eye velocity in the absence of visual signals and support the view that pursuit is regulated by extra-retinal signals that can undergo long-term plasticity...

..These results, coupled with computational modeling of SC activity, demonstrate that microsaccades are controlled by the SC and explain the link between microsaccades and visual attention...

..These results show that the SC helps decide the object of the next movement, beyond its traditional responsibility of saccade production...

..Smooth pursuit and the perception of motion direction were in temporal register and highly correlated, suggesting that pursuit can provide a real-time readout for the state of motion perception...

..This shared processing may help ensure the coordination of pursuit and saccadic eye movements in selecting a single target...

..Despite these changes, both manipulations failed to significantly alter choice behavior. These results show that FPA activity is not necessary for pursuit target selection...

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..We conclude that the neural signal encoding the direction of target motion that drives steady-state pursuit and supports concurrent perceptual judgments emanates from a shared ensemble of cortical neurons...

..Understanding how these systems interact will also help us understand how and why these circuits malfunction in a variety of developmental disorders. ..

..Understanding how these systems interact will also help us understand how and why these circuits malfunction in a variety of developmental disorders. ..

..Understanding how these systems interact will also help us understand how and why these circuits malfunction in a variety of developmental disorders. ..

..The results from these studies will therefore help refine clinical descriptions of the oculomotor system that are used to diagnose eye movement disorders in humans. ..

..These studies will therefore help refine clinical descriptions of the oculomotor system that are used to diagnose eye movement disorders in humans. ..

..Understanding how these systems interact will also help us understand how and why these circuits malfunction in a variety of developmental disorders. ..