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  • stimulus
  • Although saccades can occur in complete darkness, they are often elicited when something attracts attention and the observer directs the foveas toward the stimulus. (nih.gov)
  • Behavior
  • The saccade neural network requires involvement of a series of neurons designed to imitate the behavior of actual neuronal populations in the horizontal saccade controller. (hindawi.com)
  • Saccade metrics and behavior were analyzed for sex and group differences. (frontiersin.org)
  • The first study tested whether a 'threshold' theory of how neuronal activity cues saccade initiation is consistent with the flexible control of behavior. (queensu.ca)
  • Our results provide strong evidence against a fixed saccade threshold in either structure during flexible behavior, and indicate that threshold variability might depend on the level of inhibitory signals applied to the FEF or SC. (queensu.ca)
  • To contrast VE behavior with classic measurements, the monkeys also performed a simple Cued Saccade task. (arvojournals.org)
  • However, most of these studies have used two-dimensional displays in which most objects and the background remain stationary, requiring subjects to respond with a single type of eye movement behavior (e.g., saccades, smooth pursuits, or fixations). (arvojournals.org)
  • Additional experimental evidence suggests that information carried through this pathway bears direct functional relevance for visuomotor behavior: transient inactivation of this pathway on the thalamic level impaired oculomotor behavior in a task that required internal monitoring of saccade metrics ( Sommer and Wurtz, 2002 ). (frontiersin.org)
  • These results provide support for concurrent encoding of visuospatial attention and saccade preparation during visual search behavior. (jneurosci.org)
  • metrics
  • The simulation results corroborate the experimental Purkinje cell population activity patterns and their relation with saccade kinematic metrics. (frontiersin.org)
  • The purpose of the present experiments was to test the hypothesis that the metrics of saccades caused by the activation of distinct collicular sites depend on the strength of their projections onto the burst generators. (jneurosci.org)
  • tasks
  • During these tasks, in which subjects make delayed saccades to previously cued locations in space, many FEF neurons exhibit spatially selective persistent activity. (jneurosci.org)
  • We trained two rhesus macaques to use a joystick to navigate in a VE to complete two tasks. (arvojournals.org)
  • We then analyzed the kinematics of saccades during all tasks, and specifically during different phases of the VE tasks. (arvojournals.org)
  • Blinks effectively remove saccadic inhibition and prematurely trigger impending saccades in reaction time tasks, thus providing a behavioral readout of the premotor plan. (jneurosci.org)
  • We analyzed dorsal raphe neuron activity recorded while animals performed two reward-oriented saccade tasks. (jneurosci.org)
  • signals
  • Because the attenuated pre-saccade activity that we found in the SC may be insufficient by itself to elicit correct anti-saccades, additional movement signals from other brain areas are presumably required. (jneurosci.org)
  • Our findings suggest that the error signals for saccade adaptation are conveyed in a pathway that courses through the midbrain tegmentum. (jneurosci.org)
  • Taking advantage of the directional specificity of saccade adaptation, we further show that microstimulation creates signals that are equivalent to the neural correlate of visual error in two-dimensional space. (jneurosci.org)
  • The next two studies investigated the BG network as a likely candidate to modulate a saccade initiation mechanism, based on strong inhibitory output signals from the BG to the FEF and SC. (queensu.ca)
  • dynamics
  • Brainstem saccadic circuitry, corroborated by several contributions of local field potentials (LFPs) to the dynamics of neuronal synaptic activity between three neural populations in generating horizontal and vertical saccades in two rhesus monkeys, was introduced by van Horn et al. (hindawi.com)
  • We report that the task-dependent use of visual information can have a strong influence on the patterns of fixations, whilst not influencing saccade dynamics. (arvojournals.org)
  • neuronal
  • The theory suggests there is a fixed level of FEF and SC neuronal activation at which saccades are initiated. (queensu.ca)
  • Humans
  • Even though our findings confirm the existence of very-short-latency saccades in humans, it is questionable whether they represent a different population of saccades, as they were equally affected by the presence of distractors as are regular saccades. (arvojournals.org)
  • Here, we investigated whether such saccade-by-saccade compensation occurs in humans, and we made three new observations. (arvojournals.org)
  • Together, our results demonstrate that it is likely that a corollary discharge in humans can be used to adjust both saccade direction and amplitude following variations in individual saccades. (arvojournals.org)
  • This guidance of saccades based on an internally generated CD has been studied in both monkeys and humans using the double-step task introduced by Hallett and Lightstone ( 1976 ). (arvojournals.org)
  • To facilitate linking physiology in monkeys with psychophysics in humans, we directly compared color-detection thresholds in humans and rhesus monkeys. (arvojournals.org)
  • cues
  • In addition, monkeys with unilateral lesions exhibited specific impairment only in the performance of memory-guided saccades directed toward visual cues in the visual field contralateral to the lesioned hemisphere. (frontiersin.org)
  • In the present study, rhesus monkeys were trained in a novel inter-temporal choice task in which the magnitude and delay of reward were indicated symbolically using visual cues and varied randomly across trials. (frontiersin.org)
  • lesions
  • Since Jacobsen's (1936) first reported that rhesus monkeys with bilateral prefrontal lesions exhibited a severe and long-lasting impairment of delayed-response performance, the delayed-response task became an essential behavioral task for examining prefrontal functions. (frontiersin.org)
  • These two tracking deficits are similar to those described in rhesus monkeys with lesions of the medial superior temporal and middle temporal visual areas. (lancs.ac.uk)
  • Hallett
  • If the position of the first saccade can be derived from some extra-retinal input, then subjects have the information to make the saccade to the target accurately ( Figure 1A , second saccade with CD), which Hallett and Lightstone ( 1976 ) showed they could do. (arvojournals.org)
  • paradigm
  • In a paradigm in which a target on the horizontal meridian jumped vertically during the saccade (resulting in an endpoint error), the adaptive response exhibited two timescales: a fast timescale that learned quickly from endpoint error but had poor retention, and a slow timescale that learned slowly but had strong retention. (jneurosci.org)
  • Superior Colliculus
  • Neural activity was recorded in the superior colliculus (SC), a structure that is known to be involved in the generation of fast saccades, to determine whether it was also involved in the generation of anti-saccades. (jneurosci.org)
  • As a first step to identify the pathway that transmits the error signal for motor learning in saccades, we investigated the effect of local microstimulation in the medial part of the mesencephalic tegmentum, a region that contains fibers from two candidate structures that instruct the cerebellum, superior colliculus, and parvocellular red nucleus. (jneurosci.org)
  • We examined five nuclei critical for saccade initiation and modulation: the frontal eye field (FEF) in the cerebral cortex, the subthalamic nucleus (STN), caudate nucleus (CD), and substantia nigra pars reticulata (SNr) in the basal ganglia (BG), and the superior colliculus (SC) in the midbrain. (queensu.ca)
  • nuclei
  • The OMV, through the caudal fastigial nuclei, interacts with the brainstem to provide adaptive saccade gain corrections that minimize the visual error in reaching a given target location. (frontiersin.org)
  • sensory
  • A computational framework that captures these ideas is one in which motor commands are monitored via a forward model, predicting sensory consequences and allowing for within-saccade compensation. (jneurosci.org)
  • 1997
  • Saccade averaging has been explained in terms of a weighted average (Tipper, Howard, & Jackson, 1997 ), which assumes that each element evokes a peak of activity within a common saccade map. (arvojournals.org)
  • premotor
  • These studies provide abundant evidence that an SNN is well suited to evoke the properties of the firing patterns of the premotor neurons during the pulse and slide phases of a saccade. (hindawi.com)
  • sequential
  • There is strong evidence that the brain can use an internally generated copy of motor commands, a corollary discharge, to guide rapid sequential saccades. (arvojournals.org)
  • PPRF
  • It probably results from a dysfunction of brainstem ocular motor structures, in particular the paramedian pontine reticular formation (PPRF) involved in saccade generation: excitatory burst neurons (EBN), inhibitory burst neurons (IBN) and omnipause neurons (OPN). (biomedcentral.com)
  • Compared to a rostral SC site, the excitation of a caudal SC site should then engage a larger number of SC neurons projecting to the horizontal saccade generator in the PPRF, and such a gradient would account for the spatiotemporal transformation in the horizontal plane. (jneurosci.org)
  • fovea
  • Like a flick of the wrist swivels a hand-held camera, saccades swiftly point the fovea to locations of interest, ensuring high-acuity vision for the scene's relevant information. (jneurosci.org)
  • magnitude
  • It is concluded that the neural network is constrained by a minimum duration of the agonist pulse and that the most dominant factor in determining the saccade magnitude is the number of active neurons for the small saccades. (hindawi.com)
  • prefrontal
  • The frontal eye field (FEF), supplementary eye field (SEF), and dorsolateral prefrontal cortex (DPC) are considered to be the predominate brain regions involved in the generation of incongruent saccades. (jneurosci.org)
  • whereas
  • In this restricted amplitude dataset, the females with FASD made saccades with significantly lower velocity and longer duration, whereas the males with FASD did not differ from the control group. (frontiersin.org)