Postsaccadic eye position contributes to oculomotor error estimation in saccadic adaptation

2019 ◽  
Vol 122 (5) ◽  
pp. 1909-1917
Author(s):  
Svenja Gremmler ◽  
Markus Lappe
Keyword(s):  
Visual Feedback ◽  
Eye Position ◽  
Time Interval ◽  
Proprioceptive Information ◽  
Experimental Conditions ◽  
Position Information ◽  
Saccadic Adaptation ◽  
Position Signal ◽  
Motor Error ◽  
Saccade Control

We investigated whether the proprioceptive eye position signal after the execution of a saccadic eye movement is used to estimate the accuracy of the movement. If so, saccadic adaptation, the mechanism that maintains saccade accuracy, could use this signal in a similar way as it uses visual feedback after the saccade. To manipulate the availability of the proprioceptive eye position signal we utilized the finding that proprioceptive eye position information builds up gradually after a saccade over a time interval comparable to typical saccade latencies. We confined the retention time of gaze at the saccade landing point by asking participants to make fast return saccades to the fixation point that preempt the usability of proprioceptive eye position signals. In five experimental conditions we measured the influence of the visual and proprioceptive feedback, together and separately, on the development of adaptation. We found that the adaptation of the previously shortened saccades in the case of visual feedback being unavailable after the saccade was significantly weaker when the use of proprioceptive eye position information was impaired by fast return saccades. We conclude that adaptation can be driven by proprioceptive eye position feedback. NEW & NOTEWORTHY We show that proprioceptive eye position information is used after a saccade to estimate motor error and adapt saccade control. Previous studies on saccadic adaptation focused on visual feedback about saccade accuracy. A multimodal error signal combining visual and proprioceptive information is likely more robust. Moreover, combining proprioceptive and visual measures of saccade performance can be helpful to keep vision, proprioception, and motor control in alignment and produce a coherent representation of space.

Eye position effects in saccadic adaptation

2011 ◽  
Vol 106 (5) ◽  
pp. 2536-2545 ◽  
Author(s):  
Katharina Havermann ◽  
Eckart Zimmermann ◽  
Markus Lappe
Keyword(s):  
Eye Movements ◽  
Visual Space ◽  
Initial Position ◽  
Head Movements ◽  
Eye Position ◽  
Saccade Amplitude ◽  
Position Effects ◽  
Position Information ◽  
Saccadic Adaptation ◽  
Visual Error

Saccades are used by the visual system to explore visual space with the high accuracy of the fovea. The visual error after the saccade is used to adapt the control of subsequent eye movements of the same amplitude and direction in order to keep saccades accurate. Saccadic adaptation is thus specific to saccade amplitude and direction. In the present study we show that saccadic adaptation is also specific to the initial position of the eye in the orbit. This is useful, because saccades are normally accompanied by head movements and the control of combined head and eye movements depends on eye position. Many parts of the saccadic system contain eye position information. Using the intrasaccadic target step paradigm, we adaptively reduced the amplitude of reactive saccades to a suddenly appearing target at a selective position of the eyes in the orbitae and tested the resulting amplitude changes for the same saccade vector at other starting positions. For central adaptation positions the saccade amplitude reduction transferred completely to eccentric starting positions. However, for adaptation at eccentric starting positions, there was a reduced transfer to saccades from central starting positions or from eccentric starting positions in the opposite hemifield. Thus eye position information modifies the transfer of saccadic amplitude changes in the adaptation of reactive saccades. A gain field mechanism may explain the eye position dependence found.

scholarly journals Efference Copy Provides the Eye Position Information Required for Visually Guided Reaching

1998 ◽  
Vol 80 (3) ◽  
pp. 1605-1608 ◽  
Author(s):  
Richard F. Lewis ◽  
Bertrand M. Gaymard ◽  
Rafael J. Tamargo
Keyword(s):  
Visual Information ◽  
Constant Error ◽  
Efference Copy ◽  
Eye Position ◽  
Sufficient Information ◽  
Visually Guided ◽  
Position Information ◽  
Visually Guided Reaching ◽  
Position Signal ◽  
The Mean

Lewis, Richard F., Bertrand M. Gaymard, and Rafael J. Tamargo. Efference copy provides the eye position information required for visually guided reaching. J. Neurophysiol. 80: 1605–1608, 1998. The contribution of extraocular muscle (EOM) proprioception to the eye position signal used to transform retinotopic visual information to a craniotopic reference frame remains uncertain. In this study we examined the effects of unilateral and bilateral proprioceptive deafferentation of the EOMs on the accuracy of reaching movements directed to visual targets. No significant changes occurred in the mean accuracy (constant error) or variance (variable error) of pointing after unilateral or bilateral deafferentation. We concluded that in normal animals efference copy provides sufficient information about orbital eye position to code space in craniotopic coordinates.

Scaling of the Fore-Aft Vestibulo-Ocular Reflex by Eye Position During Smooth Pursuit

2006 ◽  
Vol 96 (2) ◽  
pp. 936-940 ◽  
Author(s):  
Jennifer A. Semrau ◽  
Min Wei ◽  
Dora Angelaki
Keyword(s):  
Rhesus Monkeys ◽  
Eye Position ◽  
Proprioceptive Information ◽  
Ocular Reflex ◽  
Position Signal ◽  
Vestibulo Ocular Reflex ◽  
Central Motor Commands ◽  
Pursuit Velocity ◽  
The Right ◽  
Eye Velocity

An eye position signal scales the amplitude of compensatory eye velocity in the translational vestibulo-ocular reflex (TVOR). To investigate the origin of such a modulatory signal, we studied the kinematics of the fore-aft TVOR as rhesus monkeys pursued a horizontally moving target at velocities between 0.5 and 30°/s. We found that the “V-shaped” curve of the fore-aft TVOR amplitude as a function of eye position was shifted opposite to the direction of pursuit eye movement. As a result, the tip of the V-shaped curve that occurred close to zero eye position during steady-state fixation was shifted to the right during leftward pursuit and to the left during rightward pursuit eye movements. The faster the pursuit velocity the larger the observed shift. These results suggest that the scaling of the TVOR can precede actual eye position changes by several tens of milliseconds, which averaged 169 ± 87 ms in three rhesus monkeys. Thus, central motor commands, rather than low-level efference copy or proprioceptive information, may be the signals scaling TVOR amplitude.

Corollary discharge provides accurate eye position information to the oculomotor system

Science ◽  
1983 ◽  
Vol 221 (4616) ◽  
pp. 1193-1195 ◽  
Author(s):  
B. Guthrie ◽  
J. Porter ◽  
D. Sparks
Keyword(s):  
Oculomotor System ◽  
Corollary Discharge ◽  
Eye Position ◽  
Position Information

Optokinetic Memory in the Crab, Carcinus

1966 ◽  
Vol 44 (2) ◽  
pp. 233-245
Author(s):  
G. A. HORRIDGE
Keyword(s):  
Eye Movements ◽  
Visual Field ◽  
Visual Feedback ◽  
Opposite Direction ◽  
Feedback Loop ◽  
Closed Loop ◽  
Dark Period ◽  
Eye Position ◽  
Movement Perception ◽  
Memory Experiment

1. A crab is held at the centre of an illuminated stationary striped drum or any visual field with strong contrasts. After a time all lights are turned off and the drum is moved in the dark. The light is restored when the drum is stationary in its new position. The animal responds by a movement of the eyes. 2. Stimuli of 0.5° over a dark period of 2 min. or 1° over 15 min. give a response. The response depends on the angle of the drum movement, and is slower in performance and less in total amount for longer periods of darkness. 3. On re-illumination the movement of the eye relative to the stationary drum is such that the visual field moves across the eye in the opposite direction to the eye's movement, but nevertheless the perception of small drum oscillations is not impaired. 4. When the visual feedback loop is opened by clamping the seeing eye and painting over the moving one, eye movements can be greater than drum movements, as in movement perception. Comparison of calculated with experimental closed-loop conditions shows that in the memory experiment there is no attenuation or amplification in the visual feedback loop. 5. Perception of very slow movements and stabilization of eye position could, but do not necessarily, depend on this accurate but short-lived directional memory.

Sensorimotor and Perceptual Function of Muscle Proprioception in Microgravity

1993 ◽  
Vol 3 (3) ◽  
pp. 259-273
Author(s):  
J.P. Roll ◽  
K. Popov ◽  
V. Gurfinkel ◽  
M. Lipshits ◽  
C. André-Deshays ◽  
...  
Keyword(s):  
Motor Behavior ◽  
Tibialis Anterior Muscle ◽  
Sensory Function ◽  
Whole Body ◽  
Proprioceptive Information ◽  
Muscle Vibration ◽  
Flexor Muscle ◽  
Experimental Conditions ◽  
Postural Responses ◽  
Third Dimension

Adaptive properties of the human proprioceptive systems were studied during the French-Soviet orbital flight (Aragatz mission, December 1988). The present space experiment investigated the hypothesis that the modifications of both biomechanical and physiological conditions occurring under microgravity involve considerable reorganization of body perception and postural control. The proprioceptive information originating in muscles is known to contribute, together with visual, vestibular, and sole cutaneous information to postural regulation. Moreover, by specifically activating the proprioceptive channel, muscle vibration is able to elicit both illusory movement sensations and postural responses. This experimental tool was used in microgravity in order to test various aspects of muscle sensory function. Ankle flexor and extensor vibration was applied under different experimental conditions. Quantitative analysis of motor responses was carried out on leg muscle EMG, goniometric, and kinesigraphic recordings. Joystick recordings and astronauts’ comments were used to describe the kinaesthetic sensations. The main results were as follows: 1) Under microgravity, the sensitivity of muscle receptors remains unchanged. 2) During the flight, the tonic vibration reflexes (TVR) increased significantly in flexor muscles, which exhibited a sustained tonic activity. 3) The whole-body postural responses normally induced by ankle flexor muscle vibration were suppressed, whereas they remained unchanged or were only reduced when vibrations were applied to the ankle extensor muscles. In all cases, the postural response velocity decreased. 4) A disfacilitation of the vibration-induced postural illusions was observed to occur during long-term exposure to microgravity. These illusions became atypical however. For example: body lift illusion could be induced by tibialis anterior muscle vibration, whereas it was never induced in the controls. The characteristics of the illusory body movements described under normal gravity can be restored by artificially increasing the axial foot support forces during the flight. In conclusion, these data suggest that a functional reorganization of the proprioceptive information processing occurs in microgravity, affecting both perceptual and motor aspects of behavior. It is possible that these proprioceptive adaptations may be partly attributable to the new whole-body propulsive foot functions imposed by exposure to weightlessness and to the adaptation of motor behavior to the third dimension of space.

Relation Between the Metrics of the Presaccadic Attention Shift and of the Saccade Before and After Saccadic Adaptation

2000 ◽  
Vol 84 (4) ◽  
pp. 1809-1813 ◽  
Author(s):  
J. Ditterich ◽  
T. Eggert ◽  
A. Straube
Keyword(s):  
Hierarchical Level ◽  
Saccade Target ◽  
Eye Position ◽  
Attention Shift ◽  
Short Term ◽  
Saccadic Adaptation ◽  
Attention Focus ◽  
Before And After ◽  
Saccade Size ◽  
Saccade Programming

A shift of the visual attention focus is known to precede saccades. However, how the metrics of both this presaccadic attention shift and the saccade are coupled is still unclear. We altered the saccade size by short-term saccadic adaptation to determine whether the attention focus would still be shifted to the location of the saccade target or to the modified postsaccadic eye position. The results showed that saccadic adaptation had no influence on the presaccadic attention shift. Thus either different processes determine the metrics of the attention shift and of the saccade or saccadic adaptation causes only modifications on a lower hierarchical level of saccade programming, thereby not influencing the metrics of the attention shift.

Motor Dynamics Encoding in Cat Cerebellar Flocculus Middle Zone During Optokinetic Eye Movements

1999 ◽  
Vol 82 (5) ◽  
pp. 2235-2248 ◽  
Author(s):  
Toshihiro Kitama ◽  
Tomohiro Omata ◽  
Akihito Mizukoshi ◽  
Takehiko Ueno ◽  
Yu Sato
Keyword(s):  
Time Course ◽  
Inverse Dynamics ◽  
Coefficient Of Determination ◽  
Eye Position ◽  
Middle Zone ◽  
Forward Selection ◽  
Optokinetic Response ◽  
Position Information ◽  
Stimulus Velocity ◽  
Cerebellar Flocculus

We investigated the relationship between eye movement and simple-spike (SS) frequency of Purkinje cells in the cerebellar flocculus middle zone during the optokinetic response (OKR) in alert cats. The OKR was elicited by a sequence of a constant-speed visual pattern movement in one direction for 1 s and then in the opposite direction for 1 s. Quick-phase-free trials were selected. Sixty-six cells had direction-selective complex spike (CS) activity that was modulated during horizontal (preferring contraversive) but not vertical stimuli. The SS activity was modulated during horizontal OKR, preferring ipsiversive stimuli. Forty-one cells had well-modulated activity and were suitable for the regression model. In these cells, an inverse dynamics approach was applied, and the time course of the SS rate was reconstructed, with mean coefficient of determination 0.76, by a linear weighted superposition of the eye acceleration (mean coefficient, 0.056 spikes/s per deg/s2), velocity (5.10 spikes/s per deg/s), position (−2.40 spikes/s per deg), and constant (mean 34.3 spikes/s) terms, using a time delay (mean 11 ms) from the unit response to the eye response. The velocity and acceleration terms contributed to the increase in the reconstructed SS rates during ipsilateral movements, whereas the position term contributed during contralateral movements. The standard regression coefficient analyses revealed that the contribution of the velocity term (mean coefficient 0.81) was predominant over the acceleration (0.03) and position (−0.17) terms. Forward selection analysis revealed three cell types: Velocity-Position-Acceleration type ( n = 27): velocity, position, and acceleration terms are significant ( P < 0.05); Velocity-Position type ( n = 12): velocity and position terms are significant; and Velocity-Acceleration type ( n = 2): velocity and acceleration terms are significant. Using the set of coefficients obtained by regression of the response to a 5 deg/s stimulus velocity, the SS rates during higher (10, 20, and 40 deg/s) stimulus velocities were successfully reconstructed, suggesting generality of the model. The eye-position information encoded in the SS firing during the OKR was relative but not absolute in the sense that the magnitude of the position shift from the initial eye position (0 deg/s velocity) contributed to firing rate changes, but the initial eye position did not. It is concluded that 1) the SS firing frequency in the cat middle zone encodes the velocity and acceleration information for counteracting the viscosity and inertia forces respectively, during short-duration horizontal OKR and 2) the apparent position information encoded in the SS firing is not appropriate for counteracting the elastic force during the OKR.

scholarly journals Design and Evaluation of LYSO/SiPM LIGHTENING PET Detector with DTI Sampling Method

Sensors ◽  
2020 ◽  
Vol 20 (20) ◽  
pp. 5820
Author(s):  
Zhenzhou Deng ◽  
Yushan Deng ◽  
Guandong Chen
Keyword(s):  
High Performance ◽  
Sampling Method ◽  
Average Energy ◽  
High Sensitivity ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Time Interval ◽  
Silicon Photomultiplier ◽  
Experimental Conditions ◽  
Wide Range

Positron emission tomography (PET) has a wide range of applications in the treatment and prevention of major diseases owing to its high sensitivity and excellent resolution. However, there is still much room for optimization in the readout circuit and fast pulse sampling to further improve the performance of the PET scanner. In this work, a LIGHTENING® PET detector using a 13 × 13 lutetium-yttrium oxyorthosilicate (LYSO) crystal array read out by a 6 × 6 silicon photomultiplier (SiPM) array was developed. A novel sampling method, referred to as the dual time interval (DTI) method, is therefore proposed to realize digital acquisition of fast scintillation pulse. A semi-cut light guide was designed, which greatly improves the resolution of the edge region of the crystal array. The obtained flood histogram shown that all the 13 × 13 crystal pixels can be clearly discriminated. The optimum operating conditions for the detector were obtained by comparing the flood histogram quality under different experimental conditions. An average energy resolution (FWHM) of 14.3% and coincidence timing resolution (FWHM) of 972 ps were measured. The experimental results demonstrated that the LIGHTENING® PET detector achieves extremely high resolution which is suitable for the development of a high performance time-of-flight PET scanner.

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