I have to post this…

#Tetrode recordings #Hippocampus #NeuroRat #HybridDrive

⤵️​ Giving the final touches to the #HybridDrive

In more details:

1. Adding the cone
   (painted with conductive epoxy, connected to the drive’s ground, to (try and) shield it from electrical interference, but it’s the first time I do this so I don’t know if it will work. Once on the rat, it will have a cap as well, except when plugged into the recording system.)

2. #GoldPlating
   This drive has 2 sets of tetrodes: 13 microns Nichrome wire and 17 microns Platinum-Iridium wire (testing which is best). Due to different wire material and diameter, they get gold-plated slightly differently; see this for a good plating tutorial for 12-13 um Nichrome, generously shared by John Bladon: https://github.com/elduvelle/ephys_tutorials/blob/main/4_gold_plating_Nichrome_12um.md

3. View of the finished drive.
   I am also testing the effects of implanting the tetrodes directly in the brain during surgery, or keeping them retracted in the drive and only lower them at the end of the surgery. This is for a bilateral dorsal #Hippocampus implant so it has two groups of tetrodes. I personally do not understand the point of not implanting directly in brain…

4. The guide/outer cannulas and their #Tetrodes
   Each guide cannula holds 4 tetrodes which move together, excepted 1 cannula that holds a single tetrode - to be left in the corpus callosum and used for reference. If everything works as planned. I used 27 gauge (thin walled) inner cannulas to guide the tetrodes - the smaller diameter that you can see); these do not move, only the shuttles and the tetrodes move.

Next step is implantation surgery!