Re: [visionlist] spectral sensitivity of pupil constriction in mice

Ali –

My suggestion is to use LEDs that emit around 475 nm, as we did in a study of the spectral dependence of form-deprivation myopia (Ghodsi & Stell, oral presentation at IMC 2015: attached, p. 5, abstract O13).

We used a commercially available LED array, intended for treatment of Seasonal Affective Disorder (SAD) – Philips HF3332/60 GoLITE BLU, λmax=474nm, halfwidth=25nm – which matches the peak absorption of melanopsin, in general, and specifically in mice.

This will avoid completely any illumination in the UV; and, with a long-wavelength-pass filter cutting off around 490-500 nm, you should still have adequate emission from your Ca-imaging dye in the green-yellow range, with no significant signal from the
pupilloconstricting LED.

Bill Stell

 

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 and Department of Surgery

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From: visionlist-bounces@visionscience.com on behalf of Asli Ayaz Sent: December 22, 2016 4:27 AMTo: visionlist@visionscience.comSubject: [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 Ayaz
Brain Research Institute
University of Zurich
Winterthurerstrasse 190
8057 Zurich, Switzerland

Homepage

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

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