The document discusses color vision and the visual system. It notes that while cone pigments are most efficient at different wavelengths, they are referred to as blue, green, and red pigments. It describes the three types of cone photopigments and how ganglion cells code for brightness, color, and opponent colors. Neural pathways in the brain process signals from the cones into the red-green, blue-yellow, and luminance pathways. Color blindness results from defects in the red, green, or blue cone systems. The eye performs several types of movements including saccades, vergence, pursuit, and vestibular ocular reflex to stabilize images on the retina.

3. Blind spot
Although the cone pigments have
maximum efficiency closer to violet,
green, and yellow wavelengths,
they are referred to as blue, green,
and red pigments, respectively

4. Short-wave pigment
Middle-wave pigment
Long-wave pigment

5. A single photon of light can activate a rod, whereas several
hundred photons are required to activate a cone.
Types of photopigments: Blue,Green,Red(Yellow) photopigmment

6. Additive color mixing Subtractive color mixing

8. Primetric field

9. Ganglion cells
Type 1: respond to a broad band of wavelengths. In
other words, they receive input from all three
types of cones, and they signal not specific color
but general brightness.
Type 2: code specific colors.
Type 3: opponent color cells

10. Type 3: opponent color cells
excitatory input from one type of cone
receptor and an inhibitory input from another

11. ganglion cells → lateral geniculate nucleus →
Neural pathways to V1:
red–green pathway
(signals of L- and M-cone responses)
blue–yellow pathway
(signals of S-cone and the sum of L- and M-cone responses)
luminance pathway
(signals of sum of L- and M-cone responses)
→ blobs , deep portion of layer 4C of V1 →
V8 → sensation of color

12. Color Blinding (Daltonism)

14. No Red
No Green
No Blue

15. Trichromats
Dichromats : 3 types :
•Protanopia
•Deuteranopia
•Tritanopia.
The prefixes "prot-," "deuter-,"
and "trit-" refer to defects of the
red, green, and blue cone
systems
Monochromats

16. • Red-Green Color Blindness
• Blue Weakness

18. Eye Special Movement

20.  1) Saccades
◦ If an image appears to the side, eye movements called saccades
rotate both eyes so that the image now falls on the fovea.
Likewise saccades are used to point the fovea at each word in this
sentence.
 2) Vergence
◦ If you look (i.e. direct the foveas) from a far object to a near one,
vergence eye movements are generated; convergence when
looked from far to near and divergence when looking from near to
far.
 3) Pursuit
◦ When an object that we are looking at moves, the image is kept
still on the retina by means of a pursuit eye movement (e.g.
tracking a ball or your moving finger).

21.  4) Vestibular ocular reflex (VOR)
◦ If we rotate our head, an eye movement very similar to pursuit is
elicited whose function is also to keep the image still on the
retina. it is generated by a different neural circuit, the VOR. The
VOR does not need a visual stimulus.
 5) Optokinetic Reflex (OKR)
◦ The VOR does not work well for slow prolonged movements. In
this case vision, through the OKR, assists the VOR. The OKR is
activated when the image of the world slips on a large portion of
the retina and produces a sense of self motion If an image
appears to the side, eye movements called saccades rotate both
eyes so that the image now falls on the fovea.
6) Nystagmus
7)sacalic