scholarly journals A head-mounted multi-camera system for electrophysiology and behavior in freely-moving mice

2020 ◽  
Author(s):  
Nicholas Sattler ◽  
Michael Wehr

AbstractAdvances in the ability to monitor freely-moving mice may prove valuable for the study of behavior and its neural correlates. Here we describe a head-mounted multi-camera system for mice, comprised of inexpensive miniature analog camera modules. We illustrate the use of this system with several natural behaviors including prey capture, courtship, jumping, and exploration. With a four-camera headset, monitoring the eyes, ears, whiskers, rhinarium, and binocular visual field can all be achieved simultaneously with high-density electrophysiology. With appropriate focus and positioning, all eye movements can be captured, including cyclotorsion. For studies of vision and eye movements, cyclotorsion provides the final degree of freedom required to reconstruct the visual scene in retinotopic coordinates or to investigate the vestibulo-ocular reflex in mice. Altogether, this system allows for comprehensive measurement of freely-moving mouse behavior, enabling a more holistic and multimodal approach to investigate ethological behaviors and other processes of active perception.

2021 ◽  
Vol 14 ◽  
Author(s):  
Nicholas J. Sattler ◽  
Michael Wehr

Advances in the ability to monitor freely-moving mice may prove valuable for the study of behavior and its neural correlates. Here we present a head-mounted multi-camera system comprised of inexpensive miniature analog camera modules, and illustrate its use for investigating natural behaviors such as prey capture, courtship, sleep, jumping, and exploration. With a four-camera headset, monitoring the eyes, ears, whiskers, rhinarium, and binocular visual field can all be achieved simultaneously with high-density electrophysiology. With appropriate focus and positioning, all eye movements can be captured, including cyclotorsion. For studies of vision and eye movements, cyclotorsion provides the final degree of freedom required to reconstruct the visual scene in retinotopic coordinates or to investigate the vestibulo-ocular reflex in mice. Altogether, this system allows for comprehensive measurement of freely-moving mouse behavior, enabling a more holistic, and multimodal approach to investigate ethological behaviors and other processes of active perception.


Author(s):  
Angie M. Michaiel ◽  
Elliott T.T. Abe ◽  
Cristopher M. Niell

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.


1991 ◽  
Vol 1 (2) ◽  
pp. 161-170
Author(s):  
Jean-Louis Vercher ◽  
Gabriel M. Gauthier

To maintain clear vision, the images on the retina must remain reasonably stable. Head movements are generally dealt with successfully by counter-rotation of the eyes induced by the combined actions of the vestibulo-ocular reflex (VOR) and the optokinetic reflex. A problem of importance relates to the value of the so-called intrinsic gain of the VOR (VORG) in man, and how this gain is modulated to provide appropriate eye movements. We have studied these problems in two situations: 1. fixation of a stationary object of the visual space while the head moves; 2. fixation of an object moving with the head. These two situations were compared to a basic condition in which no visual target was allowed in order to induce “pure” VOR. Eye movements were recorded in seated subjects during stationary sinusoidal and transient rotations around the vertical axis. Subjects were in total darkness (DARK condition) and involved in mental arithmetic. Alternatively, they were provided with a small foveal target, either fixed with respect to earth (earth-fixed target: EFT condition), or moving with them (chair-fixed-target: CFT condition). The stationary rotation experiment was used as baseline for the ensuing experiment and yielded control data in agreement with the literature. In all 3 visual conditions, typical responses to transient rotations were rigorously identical during the first 200 ms. They showed, sequentially, a 16-ms delay of the eye behind the head and a rapid increase in eye velocity during 75 to 80 ms, after which the average VORG was 0.9 ± 0.15. During the following 50 to 100 ms, the gain remained around 0.9 in all three conditions. Beyond 200 ms, the VORG remained around 0.9 in DARK and increased slowly towards 1 or decreased towards zero in the EFT and CFT conditions, respectively. The time-course of the later events suggests that visual tracking mechanisms came into play to reduce retinal slip through smooth pursuit, and position error through saccades. Our data also show that in total darkness VORG is set to 0.9 in man. Lower values reported in the literature essentially reflect predictive properties of the vestibulo-ocular mechanism, particularly evident when the input signal is a sinewave.


1987 ◽  
Vol 234 (5) ◽  
pp. 337-341 ◽  
Author(s):  
D. K�mpf ◽  
H.-F. Piper

2020 ◽  
Vol 267 (7) ◽  
pp. 2159-2163
Author(s):  
Florin Gandor ◽  
Manfred Tesch ◽  
Hannelore Neuhauser ◽  
Doreen Gruber ◽  
Hans-Jochen Heinze ◽  
...  

Abstract Objective Validation of a bedside test to objectify the fixation suppression of the vestibulo-ocular reflex (FS-VOR) in patients with a cerebellar syndrome and healthy controls. Methods The vestibulo-ocular reflex and its fixation suppression were assessed by video-nystagmography (VNG) in 20 healthy subjects (mean age 56 ± 15) and 19 patients with a cerebellar syndrome (mean age 70 ± 11). The statistical cutoff delineating normal from pathological FS-VOR was determined at the 2.5th percentile of the normal distribution of the healthy cohort. VNG was then compared to a bedside test, where eye movements were recorded with a smartphone while patients were rotated on a swivel chair at a defined speed and amplitude. These videos were rated as normal or pathological FS-VOR by six blinded raters, and results compared to VNG. Results VNG in healthy controls showed FS-VOR with a reduction of nystagmus beats by 95.0% ± 7.2 (mean ± SD). The statistical cutoff was set at 80.6%. Cerebellar patients reduced nystagmus beats by only 26.3% ± 25.1. Inter-rater agreement of the smartphone video ratings was 85%. The sensitivity of the video ratings to detect an impaired FS-VOR was 99%, its specificity 92%. Inter-test agreement was 91%. Conclusion The smartphone bedside test is an easily performed, reliable, sensitive, specific, and inexpensive alternative for assessing FS-VOR.


1985 ◽  
Vol 93 (5) ◽  
pp. 597-600 ◽  
Author(s):  
John H. Anderson ◽  
Stephen L. Liston

Vertical eye movements were recorded in alert, restrained cats that were subjected to whole-body rotations which stimulated the vertical semicircular canals. The results showed a significant asymmetry between the upward and downward slow-phase eye movements, which suggests differences in the CNS processing of vertical canal inputs vis-à-vis the vestibulo-ocular reflex.


1999 ◽  
Vol 81 (6) ◽  
pp. 2884-2892 ◽  
Author(s):  
Vallabh E. Das ◽  
Louis F. Dell’Osso ◽  
R. John Leigh

Enhancement of the vestibulo-ocular reflex by prior eye movements. We investigated the effect of visually mediated eye movements made before velocity-step horizontal head rotations in eleven normal human subjects. When subjects viewed a stationary target before and during head rotation, gaze velocity was initially perturbed by ∼20% of head velocity; gaze velocity subsequently declined to zero within ∼300 ms of the stimulus onset. We used a curve-fitting procedure to estimate the dynamic course of the gain throughout the compensatory response to head rotation. This analysis indicated that the median initial gain of compensatory eye movements (mainly because of the vestibulo-ocular reflex, VOR) was 0.8 and subsequently increased to 1.0 after a median interval of 320 ms. When subjects attempted to fixate the remembered location of the target in darkness, the initial perturbation of gaze was similar to during fixation of a visible target (median initial VOR gain 0.8); however, the period during which the gain increased toward 1.0 was >10 times longer than that during visual fixation. When subjects performed horizontal smooth-pursuit eye movements that ended (i.e., 0 gaze velocity) just before the head rotation, the gaze velocity perturbation at the onset of head rotation was absent or small. The initial gain of the VOR had been significantly increased by the prior pursuit movements for all subjects ( P < 0.05; mean increase of 11%). In four subjects, we determined that horizontal saccades and smooth tracking of a head-fixed target (VOR cancellation with eye stationary in the orbit) also increased the initial VOR gain (by a mean of 13%) during subsequent head rotations. However, after vertical saccades or smooth pursuit, the initial gaze perturbation caused by a horizontal head rotation was similar to that which occurred after fixation of a stationary target. We conclude that the initial gain of the VOR during a sudden horizontal head rotation is increased by prior horizontal, but not vertical, visually mediated gaze shifts. We postulate that this “priming” effect of a prior gaze shift on the gain of the VOR occurs at the level of the velocity inputs to the neural integrator subserving horizontal eye movements, where gaze-shifting commands and vestibular signals converge.


2009 ◽  
Vol 101 (3) ◽  
pp. 1258-1266 ◽  
Author(s):  
Daniel J. Tollin ◽  
Janet L. Ruhland ◽  
Tom C. T. Yin

The mammalian orienting response to sounds consists of a gaze shift that can be a combination of head and eye movements. In animals with mobile pinnae, the ears also move. During head movements, vision is stabilized by compensatory rotations of the eyeball within the head because of the vestibulo-ocular reflex (VOR). While studying the gaze shifts made by cats to sounds, a previously uncharacterized compensatory movement was discovered. The pinnae exhibited short-latency, goal-directed movements that reached their target while the head was still moving. The pinnae maintained a fixed position in space by counter-rotating on the head with an equal but opposite velocity to the head movement. We call these compensatory ear movements the vestibulo-auricular reflex (VAR) because they shared many kinematic characteristics with the VOR. Control experiments ruled out efference copy of head position signals and acoustic tracking (audiokinetic) of the source as the cause of the response. The VAR may serve to stabilize the auditory world during head movements.


1990 ◽  
Vol 1 (1) ◽  
pp. 23-29
Author(s):  
T.T. Khater ◽  
J.F. Baker ◽  
B.W. Peterson

Adaptive modification of vestibulo-ocular reflex (VOR) direction was characterized in humans by recording vertical and horizontal VOR eye movements during horizontal rotations in darkness at frequencies of 0.05 to 1 Hz before and after exposure to a VOR direction adaptation procedure. This procedure paired yaw horizontal vestibular rotation at 0.25 Hz with synchronous pitch vertical optokinetic motion. Saccades were removed from eye position records and VOR gain and phase were recorded. With an onset time constant of 36 min, the VOR measured during horizontal rotation in complete darkness acquired a vertical component in phase with the optokinetic stimulus presented during adaptation. The amplitude of this newly acquired vertical VOR component was maximal during rotation at the frequency of adaptation; at other frequencies, the amplitude was lower, but still significant. Unlike VOR direction adaptation in cats, the phase of the adaptive VOR component in humans did not show significant leads or lags at test frequencies below or above the adaptation frequency. These data suggest that, like the cat, the human VOR can be directionally adapted, and the pathways involving the adaptive component of the VOR are frequency specific.


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