How to embed and recover X-Headstage™?

How to embed and recover the X-Headstage™?

Embedding the X-Headstage with the electrode could improve recording quality and animal handling. The most significant barrier for many to adopt this technique is overcoming the re-usability concern. Here are some tips that might help.

Electrodes and various implanted devices are often anchored on the skull using dental acrylic.  

Recovering the X-Headstage™ means separating the headstage, and ideally the electrode, from the acrylic at the end of the experiment, likely after the brain has been perfused and extracted. Dental acrylic can be softened and dissolved by acetone. Leaving the extracted implant overnight will soften the acrylic enough to be peeled and broken off from the X-Headstage™. To minimize particles from clogging the connector pins during the soaking/detaching stage, applying a thin layer of Vaseline around the X-Headstage probe connectors during the embedding step is recommended. Also, during the application and dissolving step, it is a good practice to plug in the cable to prevent accidentally dripping acrylic into the connector.  

Embedding the X-Headstage™

• Connect the electrode to the X-Headstage™. Cover the unused connector with a cycle extension adapter if you have a 32-ch headstage that utilizes only one of the two board-to-board connectors.
• Apply Vaseline around the X-Headstage™'s probe connectors.
• Connect a cable to the X-Headstage™ system connector (HDMI or Omnetics) to protect it during the acrylic application phase.
• Some users reported and recommended a technique using a segment of a syringe tube as a container and outer barrier for holding the dental acrylic. Once the X-Headstage™ and electrode have been anchored, place this tube around the implant and then pour acrylic into it to hold and protect the whole implant. This tube also serves as a handling point to easily plug in the cable for data collection.

Recovering X-Headstage™

• Suspend the extracted implant in the middle of a beaker or jar.
  
  A custom holder can be made by drilling a hole in the lid of the jar to feed an old cable through and then applying epoxy/glue.
  
  Fill the jar with acetone just below the HDMI connector. Apply Vaseline around the system connector joint (HDMI or Omnetics) to minimize the amount of acetone vapor leaking into the connector. Leave to soak overnight.

• The solvent in the jar will be murky, and particles will fall to the bottom of the jar. Remove the extracted implant and carefully peel off the softened acrylic until the EIB or probe PCB is exposed and can be removed.  You may repeat the soaking step to remove the acrylic.

• Clean any residual particles from the connector by spraying a gentle acetone stream if necessary.

• Let the X-Headstage™ air dry.

• Verify the X-Headstage™ functionality using theimpedance test module andbrainwave simulator.  The headstage should be able to perform measurement and recording at the proper level.
• The X-Headstage™ is ready for another round of experiments!