scholarly journals Neuronal responses to target onset in oculomotor and somatomotor parietal circuits differ markedly in a choice task

2013 ◽  
Vol 110 (10) ◽  
pp. 2247-2256 ◽  
Author(s):  
J. Kubanek ◽  
C. Wang ◽  
L. H. Snyder
Keyword(s):  
Transient Response ◽  
Rise Time ◽  
Oculomotor System ◽  
Choice Task ◽  
Striking Difference ◽  
Target Onset ◽  
Visually Guided ◽  
Neuronal Responses ◽  
Visually Guided Movement ◽  
Reach Planning

We often look at and sometimes reach for visible targets. Looking at a target is fast and relatively easy. By comparison, reaching for an object is slower and is associated with a larger cost. We hypothesized that, as a result of these differences, abrupt visual onsets may drive the circuits involved in saccade planning more directly and with less intermediate regulation than the circuits involved in reach planning. To test this hypothesis, we recorded discharge activity of neurons in the parietal oculomotor system (area LIP) and in the parietal somatomotor system (area PRR) while monkeys performed a visually guided movement task and a choice task. We found that in the visually guided movement task LIP neurons show a prominent transient response to target onset. PRR neurons also show a transient response, although this response is reduced in amplitude, is delayed, and has a slower rise time compared with LIP. A more striking difference is observed in the choice task. The transient response of PRR neurons is almost completely abolished and replaced with a slow buildup of activity, while the LIP response is merely delayed and reduced in amplitude. Our findings suggest that the oculomotor system is more closely and obligatorily coupled to the visual system, whereas the somatomotor system operates in a more discriminating manner.

Pulsed High-Voltage Sensor with Nanosecond Transient Response Rise Time

2018 ◽  
Vol 61 (9) ◽  
pp. 941-943
Author(s):  
K. Yu. Sakharov ◽  
M. Yu. Denisov ◽  
V. L. Ugolev ◽  
R. A. Rodin
Keyword(s):  
Transient Response ◽  
High Voltage ◽  
Rise Time ◽  
Voltage Sensor

Independent coding of movement duration in a repetitive non-visually guided movement

2006 ◽  
Vol 23 (1-2) ◽  
pp. 19-24
Author(s):  
Rouzbeh Motiei-Langroudi ◽  
Mohsen Omrani ◽  
Mohammad Ali Khoshnoodi ◽  
Firouz Ghaderi Pakdel ◽  
Emad Yazdanpanah ◽  
...  
Keyword(s):  
Movement Duration ◽  
Visually Guided ◽  
Visually Guided Movement

Reference Frames for Reach Planning in Macaque Dorsal Premotor Cortex

2007 ◽  
Vol 98 (2) ◽  
pp. 966-983 ◽  
Author(s):  
Aaron P. Batista ◽  
Gopal Santhanam ◽  
Byron M. Yu ◽  
Stephen I. Ryu ◽  
Afsheen Afshar ◽  
...  
Keyword(s):  
Reference Frame ◽  
Reference Frames ◽  
Premotor Cortex ◽  
Visually Guided ◽  
Electrode Arrays ◽  
Reference Frame Transformation ◽  
Frame Transformation ◽  
Visual Reference Frame ◽  
Reach Planning ◽  
The Brain

When a human or animal reaches out to grasp an object, the brain rapidly computes a pattern of muscular contractions that can acquire the target. This computation involves a reference frame transformation because the target's position is initially available only in a visual reference frame, yet the required control signal is a set of commands to the musculature. One of the core brain areas involved in visually guided reaching is the dorsal aspect of the premotor cortex (PMd). Using chronically implanted electrode arrays in two Rhesus monkeys, we studied the contributions of PMd to the reference frame transformation for reaching. PMd neurons are influenced by the locations of reach targets relative to both the arm and the eyes. Some neurons encode reach goals using limb-centered reference frames, whereas others employ eye-centered reference fames. Some cells encode reach goals in a reference frame best described by the combined position of the eyes and hand. In addition to neurons like these where a reference frame could be identified, PMd also contains cells that are influenced by both the eye- and limb-centered locations of reach goals but for which a distinct reference frame could not be determined. We propose two interpretations for these neurons. First, they may encode reach goals using a reference frame we did not investigate, such as intrinsic reference frames. Second, they may not be adequately characterized by any reference frame.

scholarly journals Are there right hemisphere contributions to visually-guided movement? Manipulating left hand reaction time advantages in dextrals

2015 ◽  
Vol 6 ◽  
Author(s):  
David P. Carey ◽  
E. Grace Otto-de Haart ◽  
Gavin Buckingham ◽  
H. Chris Dijkerman ◽  
Eric L. Hargreaves ◽  
...  
Keyword(s):  
Reaction Time ◽  
Right Hemisphere ◽  
Visually Guided ◽  
Left Hand ◽  
Visually Guided Movement

scholarly journals Myoclonic-like Finger Microdisplacements in Patients With Cerebellar Deficits

1995 ◽  
Vol 22 (2) ◽  
pp. 144-152 ◽  
Author(s):  
Anne Beuter ◽  
John G. Milton ◽  
Christiane Labrie ◽  
Deborah Black
Keyword(s):  
Healthy Subjects ◽  
Index Finger ◽  
Neurological Deficits ◽  
Unexpected Finding ◽  
Physiological Tremor ◽  
Visually Guided ◽  
Cerebellar Disease ◽  
Simple Motor ◽  
Finger Position ◽  
Visually Guided Movement

AbstractBackground:Here we assess the ability of patients with cerebellar disease to execute a simple visually-guided movement task involving tracking of a target with the index finger.Methods:Spontaneous microdisplacements in index finger position are compared in patients with cerebellar deficits (ischemia [n = 3], multiple sclerosis [n = 3], degenerative cerebellar disease [n = 3]) and age-matched healthy subjects. Subjects were required to maintain a constant finger position relative to a stationary baseline displayed on an oscilloscope.Results:Unusual transient abrupt movements (saccadic or myoclonic-like) directed with or against gravity were seen in patients whose neurological deficits were the most severe (7/9 patients). These abrupt myoclonic-like movements occurred independently of visual input, were not associated with clinically observable myoclonus, and were not detected previously in patients with Parkinson’s disease. These abrupt myoclonic-like movements were not associated with abnormalities in either physiological tremor, or oscillations in finger microdisplacements induced by insertion of a delay (300–1400 ms) into the visual feedback of this finger “holding” experiment. An unexpected finding is that the results obtained for patients with cerebellar deficits by insertion of an experimental delay are not significantly different from those obtained with their age-matched controls.Conclusions:These observations suggest that abrupt myoclonic-like movements are a characteristic abnormality of patients with a variety of cerebellar deficits and emphasize the value of this simple motor tracking task for characterizing movement disorders.

Trial-to-Trial Variability of Spike Response of V1 and Saccadic Response Time

2010 ◽  
Vol 104 (5) ◽  
pp. 2556-2572 ◽  
Author(s):  
Jungah Lee ◽  
HyungGoo R. Kim ◽  
Choongkil Lee
Keyword(s):  
Response Time ◽  
Firing Rate ◽  
Spike Activity ◽  
Cell Activity ◽  
Onset Time ◽  
Neural Response ◽  
Target Onset ◽  
Visually Guided ◽  
Spike Response ◽  
Saccadic Response

Single neurons in the primary visual cortex (V1) show variability in spike activity in response to an identical visual stimulus. In the current study, we examined the behavioral significance of the variability in spike activity of V1 neurons for visually guided saccades. We recorded single-cell activity from V1 of monkeys trained to detect and make saccades toward visual targets of varying contrast and analyzed trial-to-trial covariation between the onset time or firing rate of neural response and saccadic response time (RT). Neural latency (NL, the time of the first spike of neural response) was correlated with RT, whereas firing rate (FR) was not. When FR was computed with respect to target onset ignoring NL, a “false” correlation between FR and RT emerged. Multiple regression and partial correlation analyses on NL and FR for predictability of RT variability, as well as a simulation with artificial Poisson spike trains, supported the conclusion that the correlation between FR with respect to target onset and RT was mediated by a correlation between NL and RT, emphasizing the role of trial-to-trial variability of NL for extracting RT-related signals. We attempted to examine laminar differences in RT-related activity. Neurons recorded in the superficial layers tended to show a higher sensitivity to stimulus contrast and a lower correlation with RT compared with those in the lower layers, suggesting a sensory-to-motor transformation within V1 that follows the order of known anatomical connections. These results demonstrate that the trial-to-trial variability of neural response in V1 propagates to the stage of saccade execution, resulting in trial-to-trial variability of RT of a visually guided saccade.

scholarly journals Effects of Processing Difficulty on Eye Movements in Reading: A Review of Behavioral and Neural Observations

2012 ◽  
Vol 5 (4) ◽  
Author(s):  
Shun-nan Yang
Keyword(s):  
Eye Movements ◽  
Electric Current ◽  
Present Article ◽  
Onset Time ◽  
Target Onset ◽  
Visually Guided ◽  
Applied Current ◽  
Effect Theory ◽  
Reading Text ◽  
Processing Difficulty

In reading, text difficulties increase the duration of eye fixation and the frequency of refixation and regression. The present article reviews previous attempts to quantify these effects based on the frequency of effect theory (FET), and links these effects to results from microstimulation of primate supple-mentary eye fields. Observed stimulation effects on the latency and frequency of visually-guided saccades depend on the onset time of electric current relative to target onset, and the strength of applied current. Resultant saccade delay was only observed for those made towards a highly predictive location ipsilateral to stimulated SEF sites. These findings are inter-preted in the context of reading, where the detection of processing difficulty allows a suppression signal to supersede a forward saccade signal in a time race. This in turn permits a cognitively-based refixation/regression to be initiated in place of the suppressed forward saccade.

scholarly journals The Limitations of Reward Effects on Saccade Latencies: An Exploration of Task-Specificity and Strength

Vision ◽  
2019 ◽  
Vol 3 (2) ◽  
pp. 20 ◽  
Author(s):  
Stephen Dunne ◽  
Amanda Ellison ◽  
Daniel T. Smith
Keyword(s):  
Eye Movements ◽  
Operant Conditioning ◽  
Saccadic Eye Movements ◽  
Oculomotor System ◽  
Saccade Latency ◽  
Visually Guided ◽  
Task Specificity ◽  
Specific Effects ◽  
Spatial Locations

Saccadic eye movements are simple, visually guided actions. Operant conditioning of specific saccade directions can reduce the latency of eye movements in the conditioned direction. However, it is not clear to what extent this learning transfers from the conditioned task to novel tasks. The purpose of this study was to investigate whether the effects of operant conditioning of prosaccades to specific spatial locations would transfer to more complex oculomotor behaviours, specifically, prosaccades made in the presence of a distractor (Experiment 1) and antisaccades (Experiment 2). In part 1 of each experiment, participants were rewarded for making a saccade to one hemifield. In both experiments, the reward produced a significant facilitation of saccadic latency for prosaccades directed to the rewarded hemifield. In part 2, rewards were withdrawn, and the participant made a prosaccade to targets that were accompanied by a contralateral distractor (Experiment 1) or an antisaccade (Experiment 2). There were no hemifield-specific effects of the reward on saccade latency on the remote distractor effect or antisaccades, although the reward was associated with an overall slowing of saccade latency in Experiment 1. These data indicate that operant conditioning of saccadic eye movements does not transfer to similar but untrained tasks. We conclude that rewarding specific spatial locations is unlikely to induce long-term, systemic changes to the human oculomotor system.

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