Hi guys,
What kind of stimulating electrode you are using to deliver stimulation to induce LTP? I used a concentric bipolar electrode to induce evoked response in whole cell clamp mode in the past. But it is said that the concentric bipolar electrode is too large and may over-stimulate or even damage the tissue.
I saw a few posters online, where people suggested to use home-made one, like "bipolar stimulating electrodes fabricated from Formvar-coated Nichrome wires (50 um bare diameter; catalog #762000 (link is external); A-M Systems, Carlsborg, WA)."
http://www.scientistsolutions.com/forum/anatomy-and-physiology-electrophysiology/help-stimulation-electrodes
I have found a roll such wires in my lab, but the wire itself is very soft. Would a electrode made of such wire be strong enough to penetrate tissue? Is it possible for the electrode to drift in the tissue due to the same reason?
I am new to field recording even I do have a few years experience in whole cell recording.
Any suggestion will be highly appreciated.
Thanks,
-Fading
Hello, I use glass theta capillaries filled with ACSF. you can decide the tip size of the electrode according to the path that you have to stimulate. regards David
Thank you, Davide and Tomasz, for your answers. I did see people using monopolar electrode to induce LTP.
What is the advantage of using monopolar electrodes over bipolar ones in general? As far as I know, bipolar electrodes only stimulate local tissues in contact, while monopolar ones stimulate diffusely over the whole incubation chamber.
Is there any basic principle to choose a right electrode to deliver stimulation?
Cheers
Hello,
Stimulation electrode made of twisted nichrome wires inserted in a patch pipette as a holder is efficient. Let a maximum of 2-3 cm of wire beyond the edge of the pipette. You can perform slight cut of electrode extremity to modify the space between the 2 wires. Glue the wire to the two ends of the pipette. The glass pipette brings the rigidity you expect to penetrate the tissue. This type of pipette might be less large than concentric bipolar electrode. If the glass pipette is correctly fixed to its micromanipulator it will not slip so you will avoid drifting into the tissue.
Hope it will help you.