If you need help selecting the right products, ensuring their compatibility with other research equipment, using or servicing already purchased devices, please contact us at email@example.com or look for an answer on the list of frequently asked questions below:
- Two-photon microscopy (through cranial window or thinned skull)
- Electrophysiology in vivo: patch-clamp, intracellular, extracellular, multi-channel
- Instristic optical signal (IOS) imaging, a.k.a. “optical BOLD”
- Voltammetry; ion sensing; microdialysis
- Removes the need for general anesthesia while ensuring stable head-fixed configuration
- Various imaging and el-phys techniques can be performed in combination
- Exponentially reduced stress and shortens habituation time compared to full-body restraint and treadmills
- Allows head-fixed mice to run on a flat floor and explore the cage environment with whiskers and paws
- Small and slim, fits under the frame of all major microscope brands
- Does not require customization of existing equipment
- Fast, easy insertion and removal of the mouse via precision-engineered head fixation unit
- Extensively tested at Neurotar for contract research provision prior to release for general sale
- Full-body restraint, by inserting the animal into a tube and/or or wrapping it tightly and rewarding it continually via sucrose or water scheduling. (Note: this is also known as “restraint stress” paradigm in stress and depression research)
- Training a mouse to run on top of an air-lifted styrofoam ball (usually combined with visual Virtual Reality)
- Linear treadmills, again requiring rewards and/or water scheduling
- Mice running on a circular or cylindrical treadmill
All these alternatives induce stress for the mice due to unnatural environment, and are highly labor-intensive for the researchers.
The current versions of the MHC and MHC-L are designed for mice. We are currently adapting the MHC-L (Mobile HomeCage Large) for use with rats. The estimated release date for MHCL-rat is end of 2017.
Yes. They are manufactured from stainless steel and can be reused after soaking overnight in acetone to remove dental cement and cyanoacrylate.
When the cranial window implantation surgery is done correctly, it does not affect the mouse’ lifespan and health status. We have been keeping operated animals for up to one year.
Four postnatal weeks (P28) is the earliest we would recommend (around this age, the skull growth is completed in mice). Window implantation at later stages is also feasible; we have performed this surgery on aged animals (10+ months) in our studies on Alzheimer’s disease model mice.
We assist MHC users by providing live online training, showing a detailed video of the surgery, and answering any questions that arise along the way.
Via cloth-wrapping. Our technique is rapid, efficient and standardized to reduce variability and stress to the animal. No anesthesia is used during insertion into or removal from the MHC.
The duration of a typical imaging/recording session is 1-2 hours. Longer sessions up to 5-10 hours are possible as long as the animal is provided with adequate hydration and sucrose treats.
Our recommended mouse training/habituation protocol involves twice daily training sessions for 4 days (total 8 training sessions, 2 hours per session). Behavioral signs of stress are markedly reduced already on the first day, and any stress-induced dip in body weight recovers on day two. The training session consists in head-fixing the mouse in the MHC and occasionally monitoring is (remote monitoring via a closed-loop camera streaming the video of the mouse to your computer screen).
Sources of sound or smell and reinforcement systems (positive and negative) can be mounted on the MHC bridge or on the head fixation clamp. Some sensory stimuli, e.g. novel objects with distinct surface structure, colors, patterns and smell, can be positioned directly into the carbon cage (either attached to the wall or placed on the floor) as long as they do not impede the movement.
It is feasible to implement various reward systems in the MHC, e.g. a sucrose lick port for positive reinforcement or an air-puff tube for negative reinforcement. The bridge and clamp have screw holes for such applications. We are actively collaborating with other companies and laboratories to create standardized solutions.
Water and food may be delivered to the head-fixed mouse either manually or via automated tubes/feeding ports.
We recommend a 25x water immersion objective with high NA (e.g., 1.05). The maximum imaging depth typically -achievable is 700-900 micrometers.
Z-stacks can be taken in a stable manner with micrometer-scale precision. Please note that, while the skull is immobilized by fixing it through the metal headplate to MHC’s head fixation frame, the brain always has some degree of freedom to move inside the skull. Thus, axial displacements of 1,3-1,5 micrometers can be expected; however, these displacements are elastic (e.g., cells/organelles will return to exactly the same position on the image, without a continuous “drift”).
Both intra- and extracellular recordings have been performed in the MHC. We and others have performed blind patch-clamping in both whole-cell and juxtacellular modes, holding the cells for up to one hour in awake behaving mice. Electrical noise is no greater than with standard patch-clamping in a brain slice setup. Also, 16-channel silicon probes and glass electrodes have been used by several research groups and produced extremely stable, high-quality recordings.
MHC has been used with a wide variety of manipulators (including Luigs&Neumann, Narishige, Scientifica, Sutter, Sensapex etc). Our own setup consists of the 3-axis Sensapex manipulator mounted on top of a Narishige manual 3-axis manipulator. In collaboration with micromanipulator providers, we have developed a number of adapters designed for mounting the manipulators directly on the MHC bridge (please contact us for more information).
All dorsal structures are accessible for optical imaging in the MHC; for electrophysiological recordings, any brain region can be accessed (if the recording electrode can be made sufficiently long and inserted at a feasible angle).
MHC is designed to ensure maximal compatibility with all commercially-available microscopes provided by Olympus, Zeiss, Leica, Nikon, Scientifica, Sutter, Bruker, Femtonics, ThorLabs and other vendors. A variety of xy-translation stages have been used with MHC, including Prior’s z-deck and other models capable of carrying the weight of MHC with other accessories, e.g. micromanipulators or reward systems. We will work with you to ensure that all critical dimensions/clearances are measured prior to purchasing MHC (e.g., vertical distance between the objective and xy-stage, horizontal distance between the objective axis and the microscope frame, etc).
Sutter MOM, and the latest systems from Neurolabware and Femtonics can accommodate the MHC-L without any modifications to the device or the carbon cage. MHC-L can be adapted for Scientifica’s Vivoscope, ThorLab’s Bergamo and Bruker’s Ultima. Please contact firstname.lastname@example.org for further help.
The MHC can operate either with a standard laboratory source of compressed air, or with a stand-alone air pump (turbine). The recommended air flow rate is 100-120 liters per minute. The air pressure requirements are less critical (typically, 0.1-0.2 bar pressure is sufficient). Should your laboratory air supply be insufficient, we can recommend a third-party air pump model that we and many of other MHC users have been using successfully.
The MHC is designed from aircraft-grade aluminium alloy and carbon fiber to be maximally silent and vibration free. Acoustic noise produced by the MHC is essentially whisper-level, comparable to a typical laboratory background noise at 35-40dB. When an air pump is used, the noise can be somewhat higher but not to the level of being stressful. To minimize the noise, use our noise reduction unit or place the Mobile HomeCage away from the air source.
There are no special temperature and humidity requirements. The MHC kit (standard delivery) comes in a cardboard box with a foam insert. The MHC is a robust device that does not require cleaning on regular basis. Please note that pouring a solution into the MHC might block the air holes. It is, however, easy to open, wash and reassemble. Please contact us should you require further advice. Carbon cages should not be kept in places where room temperature exceeds 30 degrees Celsius.
One year standard warranty for all metal parts; 6 months warranty for all other parts.