detecting licks with neurophysiology

[Tanya Sippy]

Hello thomas, 

I hope all is well. I was thinking of using PyControl with electrophysiological recordings soon. However, it occurred to me that to detect licks, I cannot use a capacitance based lickometer as this will add noise to my recordings with each lick. Should I use an IR beam instead with some firm plastic tubing for the "spout"? How do others solve this problem with physiological recordings? Apologies if this has been previously addressed. 

thank you, 

Tanya 

[Thomas Akam]

Hi Tanya,

Before trying to implement an alternative lickmeter, I would first check whether the electrical lickometer does in fact generate artifacts that are problematic for ephys recordings.  The currents used by the lickometer are very small and it is possible that when using local referencing (i.e. referencing each channel to the average signal from of all electrodes in the same brain region) the artifact may be small enough not to cause problems. 

If you find that even with local referencing the electrical artifacts are still a problem, you could try making an IR beam based lickometer by modifying a poke board -  remove the IR components from the board and mount them on either side of a spout, with an additional resistor in series with the IR led to reduce the brightness (as the IR components will be much closer together).  I have not tried this myself so do not know how reliably you can detect licks this way.

best,

Thomas