Sensation, Perception and Vision

• Sensation and perception involve psychophysics and psychology, and differentiating between the perceptible and imperceptible.
• Subliminal stimuli occur below the threshold of sensation or consciousness, affecting the mind without awareness.
• Stimuli below the limin are out of conscious awareness but still being processed by the visual system.

Vision

• Light enters through the cornea.
• The iris, the colored part of the eye, can be blue (recessive) or brown (dominant).
• Everyone has a blind spot where the optic nerve meets the back of the retina.
• The Polaris star is in line with the blind spot.
• The Scholrea cannot feel pain, as there are no pain receptors in the eye.

Optical Nerves

• The optical tract is a bundle of nerve fibers carrying visual information from the optic chiasm to the lateral geniculate bodies.
• Green light from the left side goes to the left visual cortex, crossing to the right side of the brain.
• The optic nerve comprises millions of nerve fibers sending visual messages to the brain.
• The optic chiasm, where optic nerves cross, is crucial for the visual pathway. also, if the corpus colostomy is performed the chiasm is broken/cut.
• Optic radiation refers to the white matter tracts forming the majority of the lateral wall of the atrium of the lateral ventricle.
• The lateral geniculate nucleus serves as the relay station between the eye and the visual cortex.

Seeing in Color

• Rods and cones enable seeing in colors and differentiating ambient light at night.

Cones

• Cones facilitate daylight vision, central vision, and color vision.
• The fovea, a 1.5mm wide depression in the inner retinal surface, has a photoreceptor layer specialized for maximum arousal and visual activity.
• Cones are concentrated in the center of the retina and clustered in the retina.

Rods

• Rods support night vision, peripheral vision, and capturing light in the dark.

Color Vision

• Trichromatic color vision involves three color receptors: RGB (red, green, blue).
• The opponent process involves color perception through receptors differentiating between antagonistic responses to pairs of colors.
• Color vision is a combination of processes.
• Color blindness is a deficiency in the brain's ability to distinguish colors and is more prevalent in males.

Perceiving Things

• Perception depends on individual perspective and orientation.
• The brain processes physical stimuli based on personal experience.
• Integration of sensory input is essential.
• Perceptual set refers to the brain's readiness to perceive stimuli in a specific way.
• Reversible figures exemplify perception.