Detection of thermal responses of the retina by use of polyvinylidene fluoride multilayer detector.

Abstract

The design and properties of thermal detectors constructed with multiple layers of polyvinylidene fluoride film are described. By use of these detectors, production of heat by the photoreceptors in the darkadapted bullfrog retina in response to brief pulses of very weak light was examined.In response to brief light pulses delivering an average of 1 photon per retinal rod, the retina was found to produce heat more-or-less abruptly after a latent period of 0.2 to 0.4 s. At this level of pulse intensity, the thermal energy produced by the retina was approximately 1,500,000times as large as the total radiant energy delivered to the retina for stimulation. It appears possible that a large number of disks in the rod outer segment are activated by absorption of a single photon.

Heat generation associated with synaptic transmission in the mammalian superior cervical ganglion

“…The details of the design and the characteristics of PVDF detectors have been reported (Tasaki et al, 1987). The detectors employed were constructed by using 4-6 layers of 2 X 2 (or 2 X 3 ) mm2 PVDF connected to an operational amplifier (OPA 128) in a current-to-voltage conversion mode (see Fig.…”

“…(Note that an increase in the number of PVDF layers enhances the sensitivity and prolongs the response time.) The method of calibration of the detectors was described previously (Tasaki and Nakaye, 1986;Tasaki et al, 1987). Briefly, the responsivity of the detector was determined by converting the I I Fig.…”