I am trying to induce LTP of excitatory field-potentials in the
cortical area 17 of adult mice, and I encounter a few problems...
Currently, I am stimulating in layer IV and recording in layer II/III,
as suggested Kirkwood & Bear. It doesn't seem to work very well, but
there might be many reasons :
- The age of the animals ?
Most people studying visual cortex LTP are working on cat or rat. With
rats, some obtain LTP in adults, other claim that it only happens
during a critical period (postnatal days 15-30, more or less).
Should I try to use younger animals or to add BMI to the ACSF ?
- The pattern of the conditionning stimulus ?
TBS (Theta Burst Stimulus) ?
Tetanic stimulation ? - what frequency ? Some use 100 Hz-1 min,
repeated 3 times ; others 2 Hz-10 min...
- Electrodes' positionning ?
I do it approximately, but is there a simple technique to localize the
cortical layers in vivo ?
Or any other reason you could think of...
Thank you very much for your help !