40
JERALD J. BERNSTEIN
ft-L. At this time it is not possible to draw a direct correlation (isomorphism ) between retinal and tectal events in the goldfish.
The brief conduction time in the goldfish optic nerve allowed a clear
demonstration that the ERG b wave (latency to arrow is 39 msec)
occurred after the tectum had been excited (latency to arrow is 16.7
msec ) and was not directly involved in information transmission. Relative biological and system noise averages are shown as an indicator of
signal validity. The order of presentation from the top is ERG, FRP,
and TER (Dawson and Bernstein, 1970).
D. Spectral Sensitivity of Optic Tectal Units
By means of perimetry, goldfish were presented movable spots of
colored light (subtending angles of 1' or 2') which were of 22 different
wavelengths (341-779 mp) and were adjusted to threshold (Jacobson,
1964a,b ) . Electrophysiological recordings were taken from units in the
optic tectum. After dark adaptation the scotopic spectral sensitivity curve
was determined for on, off, and on-off units. The scotopic sensitivity
curve fitted the absorption spectra of a visual pigment at 533 nip. This
good fit between the scotopic spectral sensitivity curve of all types of
units recorded and the absorption spectrum of the visual pigment at
533 mp demonstrated that the most probable visual pigment in the
goldfish rods is porphyropsin. The spectral sensitivity curve (light
adapted) corresponded to the absorption spectrum of a visual pigment
at 467 mp which is indicative of the visual pigment cyanopsin. Therefore, it was concluded by these electrophysiological measures that visual
pigments porphyropsin and cyanopsin are the two cone visual pigments
within the fish retina (Jacobson, 1964a,b). These data agreed with the
spectral maxima of two of the three pigments of goldfish cones analyzed
by chemical methods (Marks, 1963). On and off units within thc optic
tectum had different spectral sensitivity functions than could be estimated from the visual pigments (Jacobson, 1964a,b). After light adaptation photic scnsitivity curves of tectal units were narrower than the
visual pigment absorption curves. The units had maxima at 462, 497517, 552584, and 605-651 mp. There are therefore three classes of
these tectal units which can be categorized as red-green units (maxima
of 630-651 and 497-517 mp), rcd-blue units (maxima of 605-651 and
462 my), and yellow-blue units (maxima of 552-605 and 462 mp). These
tectal recordings demonstrate that there may be three types of cones in
the goldfish retina, each type containing a different pigment with absorption and sensitivity maxima at about 467, 533, and 620 mp. However,
JERALD J. BERNSTEIN
ft-L. At this time it is not possible to draw a direct correlation (isomorphism ) between retinal and tectal events in the goldfish.
The brief conduction time in the goldfish optic nerve allowed a clear
demonstration that the ERG b wave (latency to arrow is 39 msec)
occurred after the tectum had been excited (latency to arrow is 16.7
msec ) and was not directly involved in information transmission. Relative biological and system noise averages are shown as an indicator of
signal validity. The order of presentation from the top is ERG, FRP,
and TER (Dawson and Bernstein, 1970).
D. Spectral Sensitivity of Optic Tectal Units
By means of perimetry, goldfish were presented movable spots of
colored light (subtending angles of 1' or 2') which were of 22 different
wavelengths (341-779 mp) and were adjusted to threshold (Jacobson,
1964a,b ) . Electrophysiological recordings were taken from units in the
optic tectum. After dark adaptation the scotopic spectral sensitivity curve
was determined for on, off, and on-off units. The scotopic sensitivity
curve fitted the absorption spectra of a visual pigment at 533 nip. This
good fit between the scotopic spectral sensitivity curve of all types of
units recorded and the absorption spectrum of the visual pigment at
533 mp demonstrated that the most probable visual pigment in the
goldfish rods is porphyropsin. The spectral sensitivity curve (light
adapted) corresponded to the absorption spectrum of a visual pigment
at 467 mp which is indicative of the visual pigment cyanopsin. Therefore, it was concluded by these electrophysiological measures that visual
pigments porphyropsin and cyanopsin are the two cone visual pigments
within the fish retina (Jacobson, 1964a,b). These data agreed with the
spectral maxima of two of the three pigments of goldfish cones analyzed
by chemical methods (Marks, 1963). On and off units within thc optic
tectum had different spectral sensitivity functions than could be estimated from the visual pigments (Jacobson, 1964a,b). After light adaptation photic scnsitivity curves of tectal units were narrower than the
visual pigment absorption curves. The units had maxima at 462, 497517, 552584, and 605-651 mp. There are therefore three classes of
these tectal units which can be categorized as red-green units (maxima
of 630-651 and 497-517 mp), rcd-blue units (maxima of 605-651 and
462 my), and yellow-blue units (maxima of 552-605 and 462 mp). These
tectal recordings demonstrate that there may be three types of cones in
the goldfish retina, each type containing a different pigment with absorption and sensitivity maxima at about 467, 533, and 620 mp. However,