Eye Movements of the Crab Leptograpsus Variegatus Elicited by Imposed Leg Movements

1982 ◽  
Vol 98 (1) ◽  
pp. 151-173
Author(s):  
D. VARJÜ ◽  
D.C. SANDEMAN
Keyword(s):  
Eye Movements ◽  
Visual System ◽  
Frequency Response ◽  
Functional Significance ◽  
Horizontal Plane ◽  
Vertical Axis ◽  
Horizontal Component ◽  
Eye Rotation ◽  
Freely Moving ◽  
Leg Movements

1. The horizontal component of eyestalk movements elicited by moving the legs of blinded crabs is described. 2. The animals' bodies were fixed to a stand and the legs were supported on either a sphere or platform and subjected to movement around the three major axes (yaw, pitch, and roll). Both sinusoidal and stepped movements of the legs were studied. 3. The effect of moving the legs on one side only, homolateral or contralateral to the eyestalk was also studied. 4. The eyestalk excursion elicited by sinusoidal leg excursion around the vertical axis (yaw) is a nearly linear function of the leg excursions over the range of 1–40° peak to peak at 0.1 Hz. The amplification of the system is about 0.4 when the animal's legs are supported on a ball, and 0.8-1.0 when the legs are supported on a platform. 5. The frequency response of the system to yaw is nearly flat for eye excursions of 16° peak to peak, over the range of 0.005-0.1 Hz. 6. The visual system has a powerful braking effect on the eye rotation, when this is generated by the imposed leg movements. 7. Eyestalk responses to yaw can be interpreted to be compensatory in that they stabilize the eyes in space in freely moving animals. 8. Eyestalk movements to pitch and roll are complex. In roll, their horizontal component indicates the presence of considerable rectification in the leg proprioceptor-eye system. 9. The functional significance of the eyestalk movements in the horizontal plane is discussed. Note:

scholarly journals Vision as oculomotor reward: cognitive contributions to the dynamic control of saccadic eye movements

2021 ◽  
Author(s):  
Christian Wolf ◽  
Markus Lappe
Keyword(s):  
Eye Movements ◽  
Visual Field ◽  
Visual System ◽  
Dynamic Control ◽  
Saccadic Eye Movements ◽  
Saccade Target ◽  
Cognitive Mechanisms ◽  
Foveal Vision ◽  
Subsequent Behavior ◽  
High Level

AbstractHumans and other primates are equipped with a foveated visual system. As a consequence, we reorient our fovea to objects and targets in the visual field that are conspicuous or that we consider relevant or worth looking at. These reorientations are achieved by means of saccadic eye movements. Where we saccade to depends on various low-level factors such as a targets’ luminance but also crucially on high-level factors like the expected reward or a targets’ relevance for perception and subsequent behavior. Here, we review recent findings how the control of saccadic eye movements is influenced by higher-level cognitive processes. We first describe the pathways by which cognitive contributions can influence the neural oculomotor circuit. Second, we summarize what saccade parameters reveal about cognitive mechanisms, particularly saccade latencies, saccade kinematics and changes in saccade gain. Finally, we review findings on what renders a saccade target valuable, as reflected in oculomotor behavior. We emphasize that foveal vision of the target after the saccade can constitute an internal reward for the visual system and that this is reflected in oculomotor dynamics that serve to quickly and accurately provide detailed foveal vision of relevant targets in the visual field.

Inactivation of Semicircular Canals Causes Adaptive Increases in Otolith-Driven Tilt Responses

2002 ◽  
Vol 87 (3) ◽  
pp. 1635-1640 ◽  
Author(s):  
Dora E. Angelaki ◽  
Shawn D. Newlands ◽  
J. David Dickman
Keyword(s):  
Eye Movements ◽  
Semicircular Canal ◽  
Translational Motion ◽  
Semicircular Canals ◽  
Vertical Axis ◽  
Lateral Motion ◽  
Functional Interaction ◽  
Gaze Stabilization ◽  
Theoretical Evidence ◽  
Ocular System

Growing experimental and theoretical evidence suggests a functional synergy in the processing of otolith and semicircular canal signals for the generation of the vestibulo-ocular reflexes (VORs). In this study we have further tested this functional interaction by quantifying the adaptive changes in the otolith-ocular system during both rotational and translational movements after surgical inactivation of the semicircular canals. For 0.1–0.5 Hz (stimuli for which there is no recovery of responses from the plugged canals), pitch and roll VOR gains recovered during earth-horizontal (but not earth-vertical) axis rotations. Corresponding changes were also observed in eye movements elicited by translational motion (0.1–5 Hz). Specifically, torsional eye movements increased during lateral motion, whereas vertical eye movements increased during fore-aft motion. The findings indicate that otolith signals can be adapted according to a compromised strategy that leads to improved gaze stabilization during motion. Because canal-plugged animals permanently lose the ability to discriminate gravitoinertial accelerations, adapted animals can use the presence of gravity through otolith-driven tilt responses to assist gaze stabilization during earth-horizontal axis rotations.

scholarly journals Evaluation of the panoramic image formation in different anatomic positions

2010 ◽  
Vol 21 (5) ◽  
pp. 458-462 ◽  
Author(s):  
Daniela Brait Silva Ladeira ◽  
Adriana Dibo da Cruz ◽  
Solange Maria de Almeida ◽  
Frab Norberto Bóscolo
Keyword(s):  
Horizontal Plane ◽  
Image Formation ◽  
Vertical Axis ◽  
Image Size ◽  
Radiographic Image ◽  
Middle Portion ◽  
Image Layer ◽  
Acrylic Plate ◽  
Recorded Data ◽  
Digital Caliper

The aim of this study was to determine size, shape and position of the image layer by evaluation of the radiographic image formation in different anatomic positions. A customized phantom was made of a rectangular acrylic plate measuring 14 cm² and 0.3 cm thick, with holes spaced 0.5 cm away and arranged in rows and columns. Each column was separately filled with 0.315 cm diameter metal spheres to acquire panoramic radiographs using the Orthopantomograph OP 100 unit. The customized phantom was placed on the mental support of the device, with its top surface kept parallel to the horizontal plane, and was radiographed at three different heights from the horizontal plane, i.e., the orbital, occlusal and mandibular symphysis levels. The images of the spheres were measured using a digital caliper to locate the image layer. The recorded data were analyzed statistically by the Student'-t test, ANOVA and Tukey' test (?=0.05). When the image size of spheres in horizontal and vertical axes were compared, statistically significant differences (p<0.05) were observed in all areas, portions of the image layer and heights of horizontal plane evaluated. In the middle portion of the image layer, differences in the image size of spheres were observed only along the horizontal axis (p<0.05), whereas no differences were observed along the vertical axis (p>0.05). The methodology used in this determined the precise size, shape and position of the image layer and differences in magnification were observed in both the horizontal and vertical axes.

Neostriatal administration of somatostatin: differential effect of small and large doses on behavior and motor control

1977 ◽  
Vol 55 (2) ◽  
pp. 234-242 ◽  
Author(s):  
M. Rezek ◽  
V. Havlicek ◽  
L. Leybin ◽  
C. Pinsky ◽  
E. A. Kroeger ◽  
...  
Keyword(s):  
Motor Control ◽  
Eye Movements ◽  
Slow Wave ◽  
Rem Sleep ◽  
Differential Effect ◽  
Slow Wave Sleep ◽  
Small Doses ◽  
Freely Moving ◽  
Behavioral Excitation ◽  
Higher Doses

The administration of small doses of somatostatin (SRIF) (0.01 and 0.1 μg) into the neostriatal complex of unrestrained, freely moving rats induced general behavioral excitation associated with a variety of stereotyped movements, tremors, and a reduction of rapid eye movements (REM) and deep slow wave sleep (SWS). In contrast, the higher doses of SRIF (1.0 and 10.0 μg) caused movements to be uncoordinated and frequently induced more severe difficulties in motor control such as contralateral hemiplegia-in-extension which restricted or completely prevented the expression of normal behavioral patterns. As a result, the animals appeared drowsy and inhibited. Analysis of the sleep-waking cycle revealed prolonged periods of a shallow SWS while REM sleep and deep SWS were markedly reduced; electroencephalogram recordings revealed periods of dissociation from behavior. The administration of endocrinologically inactive as well as the active analogues of SRIF failed to induce effects comparable with those observed after the administration of the same dose of the native hormone (10.0 μg).

scholarly journals Selection of visual information for lightness judgements by eye movements

2013 ◽  
Vol 368 (1628) ◽  
pp. 20130056 ◽  
Author(s):  
Matteo Toscani ◽  
Matteo Valsecchi ◽  
Karl R. Gegenfurtner
Keyword(s):  
Eye Movements ◽  
Visual System ◽  
Visual Information ◽  
Selection Process ◽  
Sampling Strategy ◽  
Selection Strategy ◽  
Eye Fixations ◽  
Target Layer ◽  
Highly Correlated ◽  
Selection Of

When judging the lightness of objects, the visual system has to take into account many factors such as shading, scene geometry, occlusions or transparency. The problem then is to estimate global lightness based on a number of local samples that differ in luminance. Here, we show that eye fixations play a prominent role in this selection process. We explored a special case of transparency for which the visual system separates surface reflectance from interfering conditions to generate a layered image representation. Eye movements were recorded while the observers matched the lightness of the layered stimulus. We found that observers did focus their fixations on the target layer, and this sampling strategy affected their lightness perception. The effect of image segmentation on perceived lightness was highly correlated with the fixation strategy and was strongly affected when we manipulated it using a gaze-contingent display. Finally, we disrupted the segmentation process showing that it causally drives the selection strategy. Selection through eye fixations can so serve as a simple heuristic to estimate the target reflectance.

scholarly journals Dynamics of gaze control during prey capture in freely moving mice

2020 ◽  
Author(s):  
Angie M. Michaiel ◽  
Elliott T.T. Abe ◽  
Cristopher M. Niell
Keyword(s):  
Eye Movements ◽  
Visual Processing ◽  
Visual Information ◽  
Prey Capture ◽  
Active Vision ◽  
Head Movements ◽  
Visual Scene ◽  
Specific Point ◽  
Binocular Field ◽  
Freely Moving

ABSTRACTMany studies of visual processing are conducted in unnatural conditions, such as head- and gaze-fixation. As this radically limits natural exploration of the visual environment, there is much less known about how animals actively use their sensory systems to acquire visual information in natural, goal-directed contexts. Recently, prey capture has emerged as an ethologically relevant behavior that mice perform without training, and that engages vision for accurate orienting and pursuit. However, it is unclear how mice target their gaze during such natural behaviors, particularly since, in contrast to many predatory species, mice have a narrow binocular field and lack foveate vision that would entail fixing their gaze on a specific point in the visual field. Here we measured head and bilateral eye movements in freely moving mice performing prey capture. We find that the majority of eye movements are compensatory for head movements, thereby acting to stabilize the visual scene. During head turns, however, these periods of stabilization are interspersed with non-compensatory saccades that abruptly shift gaze position. Analysis of eye movements relative to the cricket position shows that the saccades do not preferentially select a specific point in the visual scene. Rather, orienting movements are driven by the head, with the eyes following in coordination to sequentially stabilize and recenter the gaze. These findings help relate eye movements in the mouse to other species, and provide a foundation for studying active vision during ethological behaviors in the mouse.

Eye Movements and Motion Perception Induced by Off-vertical Axis Rotation (OVAR) at Small Angles of Tilt after Spaceflight

1995 ◽  
Vol 115 (5) ◽  
pp. 603-609 ◽  
Author(s):  
Gilles Clement ◽  
Christian Darlot ◽  
Anna Petropoulos ◽  
Alain Berthoz
Keyword(s):  
Eye Movements ◽  
Motion Perception ◽  
Vertical Axis ◽  
Axis Rotation
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