I'm working on taking LFP signal from the hippocampus of mice brains for my project, So I wonder what percentage of the baseline signal you would consider as LTP? and what is the best period of time to take a signal for recognizing LTP after rapid and sequential stimulations?
Not an expert, but in principle anything that is significantly above a control would be valid. That said, typical numbers are 50-100% so if it is much less, you might have a problem. THe time-course and amount also depend on induction method (e..g chemical vs electrical induction) and other factors such as brain area, etc. It is common for electrical induced LTP to measure periodically. THere is some evidence that this matters... (can't remember the reference, Kandel?)
Hello Sonia,
1/ what percentage of the baseline signal you would consider as LTP?
As Mark said, no matter how small, if it is consistent and significant, it is what it is. In my case, I get between 150% average after 1xTBS (10 burst) and about 190% after chemical induction with forskolin (BL is 100%).
2/ what is the best period of time to take a signal for recognizing LTP after rapid and sequential stimulations?
That depends on your LTP project. Is it short memory formation or Late memory.
In my case, I measure LTP for 90 min post-induction and for comparison across slices, I report the values obtained after 60 min. The reason is that value at 60 min is always equal ish to the one at 90 min (in my case). This allows me sometime to stop the experiment at 62 min for some drugs that say block the LTP process. I gain 30 min in order to run another slice and go home early :).
BUT, if you're dealing with late mechanisms of LTP, you might have to run the experiment for days (at least 24hour if not more)...yiikes and good luck!
I missed one point: "It is common for electrical induced LTP to measure periodically"? The answer is Yes, you have to decide about how often. For my 2h of LTP that I do, I stimulate the SC every 20 sec.
any percentage that is significantly different to your baseline. typically 50% will be considered mild LTP and 150% strong LTP