Superior Colliculus Inactivation Alters the Weighted Integration of Visual Stimuli

Nummela, Samuel U.; Krauzlis, Richard J.

doi:10.1523/jneurosci.5480-10.2011

Cited by 24 publications

(19 citation statements)

References 49 publications

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“…Other studies of the FEF SEM show that its activity mostly follows the selection of a pursuit target, in agreement with the idea that modulation by reward and other voluntary mechanisms occurs in the inputs to, or directly on, the neurons of the FEF SEM (Mahaffy and Krauzlis, 2011a, b). The FEF SEM need not act alone in modulation of pursuit eye movement, and other evidence indicates that the superior colliculus also could play a role (Nummela and Krauzlis, 2011). …”

Section: Discussionmentioning

confidence: 99%

Reward Action in the Initiation of Smooth Pursuit Eye Movements

Joshua

Lisberger²

2012

J. Neurosci.

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Reward has a powerful influence on motor behavior. To probe how and where reward systems alter motor behavior, we studied smooth pursuit eye movements in monkeys trained to associate the color of a visual cue with the size of the reward to be issued at the end of the target motion. When the tracking task presented two different colored targets that moved orthogonally, monkeys biased the initiation of pursuit towards the direction of motion of the target that led to larger reward. The bias was larger than expected given the modest effects of reward size on tracking of single targets. Experiments with three different reward sizes suggested the bias afforded a given target depends mainly on the size of the larger reward. To analyze the effect of reward on directional learning in pursuit, monkeys tracked a single moving target that changed direction 250 ms after the onset of motion. Expectation of a larger reward led to a larger learned eye movement during the acquisition of the learned response, and during subsequent probes of what had been learned, implying that reward influenced the expression rather than the acquisition of learning. The specific effects of reward size on learning and two-target stimuli imply that the site of reward modulation is at a level where multiple target motions compete for control of eye movement, downstream from sensory processing and learning and upstream from final motor processing.

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Section: Discussionmentioning

confidence: 99%

Reward Action in the Initiation of Smooth Pursuit Eye Movements

Joshua

Lisberger²

2012

J. Neurosci.

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“…There are two possible explanations that could account for the inaccuracy sometimes observed during ipsilateral perturbations. One, the dSC microstimulation could generate activities that interfere with the processing of target motion signals (Nummela and Krauzlis, 2011). Two, the microstimulation could interfere with signals encoding the expected target location.…”

Section: Discussionmentioning

confidence: 99%

Saccadic Interception of a Moving Visual Target after a Spatiotemporal Perturbation

Filippi¹,

Goffart²

2012

J. Neurosci.

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Animals can make saccadic eye movements to intercept a moving object at the right place and time. Such interceptive saccades indicate that, despite variable sensorimotor delays, the brain is able to estimate the current spatiotemporal (hic et nunc) coordinates of a target at saccade end. The present work further tests the robustness of this estimate in the monkey when a change in eye position and a delay are experimentally added before the onset of the saccade and in the absence of visual feedback. These perturbations are induced by brief microstimulation in the deep superior colliculus (dSC). When the microstimulation moves the eyes in the direction opposite to the target motion, a correction saccade brings gaze back on the target path or very near. When it moves the eye in the same direction, the performance is more variable and depends on the stimulated sites. Saccades fall ahead of the target with an error that increases when the stimulation is applied more caudally in the dSC. The numerous cases of compensation indicate that the brain is able to maintain an accurate and robust estimate of the location of the moving target. The inaccuracies observed when stimulating the dSC that encodes the visual field traversed by the target indicate that dSC microstimulation can interfere with signals encoding the target motion path. The results are discussed within the framework of the dual-drive and the remapping hypotheses.

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“…Chemically inhibiting SC activity causes a neglect-like impairment (see Figure 1). Choices are strongly biased against the stimulus initially located inside the affected part of the visual field, in favor of whichever stimulus is located outside the affected region (Nummela & Krauzlis 2010, 2011); similar pursuit impairments occur in patients with hemineglect (Rizzo & Hurtig 1992). Conversely, artificially activating the SC biases target choice in favor of the stimulus placed at the matching location in the visual field (Carello & Krauzlis 2004).…”

Section: Evidence For a Role In Spatial Attentionmentioning

confidence: 99%

Superior Colliculus and Visual Spatial Attention

Krauzlis

Lovejoy

Zénon

2013

Annu. Rev. Neurosci.

549

488

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The superior colliculus (SC) has long been known to be part of the network of brain areas involved in spatial attention, but recent findings have dramatically refined our understanding of its functional role. The SC both implements the motor consequences of attention and plays a crucial role in the process of target selection that precedes movement. Moreover, even in the absence of overt orienting movements, SC activity is related to shifts of covert attention and is necessary for the normal control of spatial attention during perceptual judgments. The neuronal circuits that link the SC to spatial attention may include attention-related areas of the cerebral cortex, but recent results show that the SC's contribution involves mechanisms that operate independently of the established signatures of attention in visual cortex. These findings raise new issues and suggest novel possibilities for understanding the brain mechanisms that enable spatial attention.

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Superior Colliculus Inactivation Alters the Weighted Integration of Visual Stimuli

Cited by 24 publications

References 49 publications

Reward Action in the Initiation of Smooth Pursuit Eye Movements

Reward Action in the Initiation of Smooth Pursuit Eye Movements

Saccadic Interception of a Moving Visual Target after a Spatiotemporal Perturbation

Superior Colliculus and Visual Spatial Attention

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