|
| |
|
|
|
|
||||
| Home Help Feedback Subscriptions Archive Search Table of Contents | ||||
|
Fig. 3. (A) Comparison of the e-vector angle-response amplitudes of a colour
receptor (row 4P R6), a hemispheric receptor (DH R1) and a `high PS cell' (row
2D R2). All photoreceptors shown here possess similar response amplitudes to
unpolarized white light, and nearly parallel response-intensity
(R-log I) functions. They are all most sensitive to an e-vector
orientation of linearly polarized light (
max) of approximately
+45°. (B) Intracellular recordings of the e-vector angle-response curves
of two neighbouring photoreceptors (R3 and R4) within row 5. The two cells
possess 90° phase-shifted max
(max(R4)=+45° and max(R3)=-45°).
Slight re-positioning of the microelectrode after completing the recording and
staining of the first cell (R3) resulted in a 90° phase-shift of
max. Subsequent Lucifer Yellow injection showed that the
microelectrode tip had moved from R3 into the neighbouring retinula cell R4.
R4 belongs to Group I and R3 to Group II cells amongst R1-R7, and they have
their microvilli arranged at right angles. (C) To determine the polarization
sensitivity of a photoreceptor, two R-log I curves were recorded at
max and min, respectively. In this example,
the intensity shift (
i) of 0.72 log units between the linear parts of
the two fitted standard Rushton intensity-response functions corresponds to a
polarization sensitivity of 5.2.
|
