Ultrasound-modulated optical parallel speckle measurement with stroboscopic illumination in a coaxial reflection system

2006 ◽  
Vol 88 (3) ◽  
pp. 033901 ◽  
Author(s):  
Masaki Hisaka
Keyword(s):  
Stroboscopic Illumination

scholarly journals Miniaturized head-mounted device for whole cortex mesoscale imaging in freely behaving mice

2020 ◽  
Author(s):  
Mathew L Rynes ◽  
Daniel Surinach ◽  
Samantha Linn ◽  
Michael Laroque ◽  
Vijay Rajendran ◽  
...  
Keyword(s):  
Neural Activity ◽  
Glutamate Release ◽  
Wide Field ◽  
Dorsal Cortex ◽  
Perceptual Decision Making ◽  
Calcium Activity ◽  
Calcium Indicators ◽  
Stroboscopic Illumination ◽  
Freely Behaving ◽  
Sensory Evoked

ABSTRACTThe advent of genetically encoded calcium indicators, along with surgical preparations such as thinned skulls or refractive index matched skulls, have enabled mesoscale cortical activity imaging in head-fixed mice. Such imaging studies have revealed complex patterns of coordinated activity across the cortex during spontaneous behaviors, goal-directed behavior, locomotion, motor learning, and perceptual decision making. However, neural activity during unrestrained behavior significantly differs from neural activity in head-fixed animals. Whole-cortex imaging in freely behaving mice will enable the study of neural activity in a larger, more complex repertoire of behaviors not possible in head-fixed animals. Here we present the “Mesoscope,” a wide-field miniaturized, head-mounted fluorescence microscope compatible with transparent polymer skulls recently developed by our group. With a field of view of 8 mm x 10 mm and weighing less than 4 g, the Mesoscope can image most of the mouse dorsal cortex with resolution ranging from 39 to 56 µm. Stroboscopic illumination with blue and green LEDs allows for the measurement of both fluorescence changes due to calcium activity and reflectance signals to capture hemodynamic changes. We have used the Mesoscope to successfully record mesoscale calcium activity across the dorsal cortex during sensory-evoked stimuli, open field behaviors, and social interactions. Finally, combining the mesoscale imaging with electrophysiology enabled us to measure dynamics in extracellular glutamate release in the cortex during the transition from wakefulness to natural sleep.

Visual Influences on the Development and Recovery of the Vestibuloocular Reflex in the Chicken

2001 ◽  
Vol 85 (3) ◽  
pp. 1119-1128 ◽  
Author(s):  
Christopher T. Goode ◽  
Donna L. Maney ◽  
Edwin W Rubel ◽  
Albert F. Fuchs
Keyword(s):  
Hair Cell ◽  
Hair Cells ◽  
Normal Development ◽  
Image Motion ◽  
Vestibuloocular Reflex ◽  
Gradual Change ◽  
Visual World ◽  
Vestibular Hair Cells ◽  
Stroboscopic Illumination ◽  
Normal Light

Whenever the head turns, the vestibuloocular reflex (VOR) produces compensatory eye movements to help stabilize the image of the visual world on the retina. Uncompensated slip of the visual world across the retina results in a gradual change in VOR gain to minimize the image motion. VOR gain changes naturally during normal development and during recovery from neuronal damage. We ask here whether visual slip is necessary for the development of the chicken VOR (as in other species) and whether it is required for the recovery of the VOR after hair cell loss and regeneration. In the first experiment, chickens were reared under stroboscopic illumination, which eliminated visual slip. The horizontal and vertical VORs (h- and vVORs) were measured at different ages and compared with those of chickens reared in normal light. Strobe-rearing prevented the normal development of both h- and vVORs. After 8 wk of strobe-rearing, 3 days of exposure to normal light caused the VORs to recover partially but not to normal values. In the second experiment, 1-wk-old chicks were treated with streptomycin, which destroys most vestibular hair cells and reduces hVOR gain to zero. In birds, vestibular hair cells regenerate so that after 8 wk in normal illumination they appear normal and hVOR gain returns to values that are normal for birds of that age. The treated birds in this study recovered in either normal or stroboscopic illumination. Their hVOR and vVOR and vestibulocollic reflexes (VCR) were measured and compared with those of untreated, age-matched controls at 8 wk posthatch, when hair cell regeneration is known to be complete. As in previous studies, the gain of the VOR decreased immediately to zero after streptomycin treatment. After 8 wk of recovery under normal light, the hVOR was normal, but vVOR gain was less than normal. After 8 wk of recovery under stroboscopic illumination, hVOR gain was less than normal at all frequencies. VCR recovery was not affected by the strobe environment. When streptomycin-treated, strobe-recovered birds were then placed in normal light for 2 days, hVOR gain returned to normal. Taken together, the results of these experiments suggest that continuous visual feedback can adjust VOR gain. In the absence of appropriate visual stimuli, however, there is a default VOR gain and phase to which birds recover or revert, regardless of age. Thus an 8-wk-old chicken raised in a strobe environment from hatch would have the same gain as a streptomycin-treated chicken that recovers in a strobe environment.

Influence of Stroboscopic Illumination on the After-effect of Seen Movement

Nature ◽  
1963 ◽  
Vol 199 (4888) ◽  
pp. 99-100 ◽  
Author(s):  
S. M. ANSTIS ◽  
R. L. GREGORY ◽  
N. DE M. RUDOLF ◽  
D. M. MACKAY
Keyword(s):  
Stroboscopic Illumination ◽  
After Effect

scholarly journals A Comparative Study of the Flight Mechanism of Diptera

1987 ◽  
Vol 127 (1) ◽  
pp. 355-372 ◽  
Author(s):  
A. ROLAND ENNOS
Keyword(s):  
Comparative Study ◽  
High Speed ◽  
Insect Flight ◽  
Downward Movement ◽  
Wing Base ◽  
Full Support ◽  
Tethered Flight ◽  
Stroboscopic Illumination ◽  
Flight Muscles ◽  
Novel Model

1. The mechanism of dipteran flight has been investigated in a comparative study involving thorax manipulation, analysis of high-speed films and direct observation of tethered flies under stroboscopic illumination. 2. The click action observed in CCl4-anaesthetized Calliphora was found to be due to an interaction between the radial stop and the pleural wing process at the top of the upstroke. The movements occurring during unanaesthetized tethered flight were quite different as these structures were vertically separated except towards the bottom of the downstroke (Miyan & Ewing, 1985a,b). 3. Results of observations on tethered insect flight and on morphology did not give full support to either the click mechanism (Boettiger & Furshpan, 1952) or the model of Miyan & Ewing. 4. A novel model for the wingbeat is proposed. Distortion of the thorax brought about by the flight muscles results in upward and outward movement of the lateral scutum during the downstroke and inward and downward movement during the upstroke. In more advanced flies flexion lines result in a differentiated scutellar lever and parascutal shelf. Distortion is thereby limited largely to the posterior scutum. The parascutal shelf moves as a part of the scutal distortion, not as an independent element in the articulation, and the system is not bistable. 5. The automatic changes in angle of attack are caused by inertial and aerodynamic forces acting around the torsional axis of the wing during the beat, which twist the compliant wing base.

scholarly journals Two-Dimensional Parallel Dispenser for Microarray Printing

2003 ◽  
Vol 8 (5) ◽  
pp. 24-28 ◽  
Author(s):  
Andreas Kuoni ◽  
Marc Boillat ◽  
Nico F. de Rooij
Keyword(s):  
New Technologies ◽  
Drop Formation ◽  
Two Dimensional ◽  
Polyimide Substrate ◽  
Glass Slides ◽  
Stroboscopic Illumination ◽  
Array Format ◽  
Microarray Format

Parallel printing in a microarray format is becoming increasingly important. This paper presents a 2-D multi-channel dispenser with a spotting spacing of 500 μm. The dispenser is continuously loaded from a 384-well plate format and shoots upward. New technologies using polyimide substrate was developed, and the flexibility of the polyimide sheets allows scaling the dispenser up to an array format of 24 × 16. Drop formation is analyzed by stroboscopic illumination and by spotting onto glass slides. Droplets of 65 pL are dispensed in parallel up to 5 kHz at a droplet speed of 2 m/s.

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