Micromanipulation for in vivo recordings
Many neuro labs use some form of micromanipulation for their experiments. Whether it be micropipettes or microelectrode arrays, we often need to guide tiny objects with micron resolution. When I was first starting the lab, I was so overwhelmed with options. So I’m writing this for the person also currently feels overwhelmed at the choices. Plus, I have a small tip for saving some $$.
Most of us usually just buy what we used in our postdoc or PhD labs. I had used the Sensapex UMP4, but I was never too crazy about. First, the software was always buggy and the controller was always giving us issues. The touch screen would go haywire all the time (call me an old man, but I think we need an anti-touch-screen revolution…bring back real buttons and knobs). Second, physically mounting probes, pipettes, and other objects to the manipulator was always a massive pain in the ass. It wasn’t very versatile. Sensapex offers an assortment of attachments and none of them were are well designed for our applications. In many cases, when I didn’t need ultra-stability, I ended up just taping objects to the manipulator head (this detail is not included in the methods of my manuscripts). Also, the whole micromanipulator was just difficult to manuever. Sensapex had all kinds of different translation and rotation stages, but I just constantly felt like I couldn’t quite get my probes and other objects where I needed them without completely unscrewing from the optical table and scooting the whole thing around.
I guess some good things to say about Sensapex: the micromanipulator itself was nice with no drift. The digital interface was also had some good aspects (when the software wasn’t acting up). I also liked that you could plug in multiple manipulators to one controller and switch between the two. But needless to say, I wanted to switch.
In my own lab we are constantly performing in vivo recordings with our flexible microelectrode arrays or commercial silicon probes. We’ve really enjoyed the Sutter QUAD system (~$10K). It has the necessary 4-axis movement for our experiments and a wide range of motion. It also tends to be more versatile and configurable in terms of its orientation, height, etc. We’ve had no issues mounting different types of probes with different holders. It’s reliable and given us no issues. I just ordered our second one. We keep one on our surgical rig for chronic implantations, and one on an ephys rig for acute recordings and other things.
One way to save money here: Sutter micromanipulator stands are outrageously expensive (>$1K), for example the MT-75 Series. I suppose maybe these are ultra-stable? They are super bulky and robust. Maybe if we were doing patch clamping, I would have bought them. But. you can cut the cost in about half with parts from Thorlabs. We use the LPH100 stand. The MPP10 rail clamp slides into the stand, and the MPR8 dovetail rail mounts into the clamp. The QUAD then fits nicely on the rail mount. This gives a ton of flexibility. The entire arm can be rotated away from the recording area, the QUAD can be mounted in different places along the rail mount, and the dovetail can slide back and forth when needed. The height can also be adjusted easily. Here are a couple of images of what this looks like put together.
Hope this is somewhat helpful.
-Daniel
