General Principles of Perception: Johannes Müller's Law

Visual Receptors and Their Functions

• Rods are abundant in the periphery of the human retina, enabling better vision in low-light conditions.
• Cones are more useful under bright lighting conditions, responsible for color vision and visual acuity.

Photopigments and Color Perception

• Photopigments in the retina absorb light and initiate the phototransduction cascade, converting light into electrical signals for the brain.
• According to the Trichromatic Theory, human eyes can perceive three primary colors: red, green, and blue, which combine to form a wide spectrum of colors.

Color Vision and Adaptations

• Color constancy refers to the brain's ability to perceive colors consistently under varying lighting conditions despite changes in illumination.
• Color vision deficiency is commonly known as color blindness, affecting the ability to distinguish colors accurately.

Visual Processing and Acuity

• The fovea, located in the retina, is responsible for acute, detailed vision due to a high concentration of cones.
• The blind spot in the eye is caused by the absence of photoreceptors where the optic nerve exits the retina.

Cellular Function in the Retina

• Ganglion cells within the retina enable responses to specific visual features such as contrast and movement.
• Bipolar cells serve as intermediaries, transmitting signals from photoreceptors (rods and cones) to ganglion cells.

Causal Pathways in Vision

• The optic nerve (second cranial nerve) transmits visual information from the retina to the brain for processing.
• The brain encodes information related to different sensations through specific neural pathways, allowing distinct perception of various stimuli.