Invigilo™-2 Wide-Field Imaging System

Invigilo – a cortex-wide window into the brain of an awake and behaving mouse

Main benefits of the Invigilo-2

• Imaging neuronal or glial Ca2+ dynamics in combination with hemodynamics;
• Correlating BOLD-corrected Ca2+imaging with local perfusion rate via laser speckle contrast imaging (LSCI);
• Seamlessly blending functional imaging and behavioral observation as parts of a holistic neuroscience approach;
• Integrating multichannel imaging, locomotion tracking, and other behavioral data via master software.

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Is Invigilo-2 good for you?

Invigilo-2  allows imaging of the neuronal or glial calcium dynamics in combination with hemodynamics

Thanks to the recent advancement of fluorescent probes and craniotomy preparations (“crystal skull” in Kim et al, 2016 and “transparent polymer skull” in Ghanbari et al., 2019), wide-field imaging allows minimally invasive recordings of calcium signal from the entire cortex with a significantly higher sampling rate than that of the laser-scanning techniques.

Moreover, Invigilo-2 allows acquiring optical BOLD (blood oxygenation level-dependent) signal simultaneously with fluorescence imaging in multiple cortical areas. BOLD signal provides a functional readout for the blood flow. Besides that: it allows correcting the distortion of the fluorescence signal (e.g., GCaMP6-based Ca2+ signal) created by activity-dependent light adsorption by hemoglobin (Ma et al 2016).

Invigilo-2 allows correlating BOLD-corrected Ca2+ signal with local perfusion rate via laser speckle contrast imaging (LSCI)

LSCI signal is a reliable measure of the regional blood perfusion level, which provides an additional subset of hemodynamics data for mapping local changes in cortical blood flow.

Invigilo-2 is seamlessly blending functional imaging with behavioral observation as part of a holistic neuroscience approach

The word Invigilo is related to vigilant; both are derived from the Lat. verb vigilare, which means ‘to stay/keep awake’.  Invigilo-2 is the only wide-field imaging system designed for experiments in awake, head-fixed mice locomoting in 2D. The sturdy frame and the proprietary head-fixation are designed to provide maximal mechanical stability. A flat-floored carbon fiber animal cage is suspended on air, allowing the mouse to move it without strain. This creates an illusion of two-dimensional locomotion. The cage closely resembles a normal home cage: the mouse habituates faster and experiences less stress than under standard head fixation conditions. Stress reduction also contributes to stability.

Behavioral monitoring relies on a magnetic locomotion-tracking device built into the air table. The software tracks locomotion at high speed (80-100 fps) and with high resolution (1 mm). Tracking works both in dark and in light conditions. What is more, locomotion tracking facilitates other behavioral tests (open field, object recognition, social interactions, maze navigation) as well as stimuli delivery – from liquid reward to visual stimulation.

Invigilo-2 master software allows integrating multichannel imaging, locomotion tracking, and other behavioral data.

Invigilo software controls all hardware settings and synchronizes all optoelectronic components of Invigilo-2 including the high-end sCMOS camera, four LED light sources, and NIR-laser for LSCI. And all of these through a single graphical user interface! It means no more hassle of trying to coordinate different components from various vendors or laborious customization of software interaction.

Invigilo-2 highlights

• Multi-channel imaging: two epifluorescent channels (red and green), two backscatter channels (red and green), and LSCI;
• Easy focusing: the entire optical assembly including objective, external LEDs, and the camera is mounted on one motorized vertical breadboard;
• Even and reproducible illumination for backscatter imaging enabled by a radial off-axis illumination apparatus (top right image);
• Stable recordings: sturdy aluminum frame & mouse-friendly easily adjustable head-fixation ensure mechanical stability;
• Air-lifted cage with flat floor and walls, the natural source of tactile stimulation, facilitates exploratory behavior and reduces stress during imaging;
• Near-panoramic (270^o) unobstructed view for the mouse allows using virtual reality (VR), visually stimulating the mouse or video-recording its behavior.