[visionlist] spectral sensitivity of pupil constriction in mice

Dear all,

I am writing to get some advice on my experimental design. I would like to measure the pupil dilation/constriction as a measure of arousal in our experimental preparation ( I do 2-Photon calcium imaging of neuronal activity in somatosensory cortex of mice performing a tactile task) For the sake of simplicity I wanted to stimulate the pupil constriction with an LED.  I know mice have two photo receptors one in UV(~360nm) range and the other M at green (~510 nm).   Since we are imaging neural activity at wavelengths corresponding to cyan/green/yellow, I wanted to stimulate the eye at another wavelength. To make the long story short :

Is stimulating the eye at or around UV range is an option? Has anybody looked at spectral sensitivity of the pupil size of mice (my literature search failed to find one)?

My concerns/ questions are

1) 350 nm is DNA damaging wavelength (though I do not know the range of power that causes the damage)

2) Transmission of light through the lens at and near UV range is low, although reported ERG activity is still high. Would it be efficient to constrict the pupil or would I be damaging the cornea, lens ?

I can always try to shield my detection system very well and provide a visual stimuli with a screen but at the end I became curious to know the answers to the above questions. I am attaching two papers as  a reference to photo-receptor sensitivity and the light transmission through the lens.I am looking forward to your answers and advice.

Happy Holidays

Asli

Dr. Aslı AyazBrain Research InstituteUniversity of ZurichWinterthurerstrasse 1908057 Zurich, Switzerland

Homepage

E-mail: ayaz@hifo.uzh.chTel:  +41 44 63 53342Fax: +41 44 63 53303Office: Y55 H30

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