General Principles of Perception

Study Notes

The brain codes information largely in terms of which neurons are active and how active they are at any moment.
Impulses in certain neurons indicate light, whereas impulses in others indicate sound, touch, or other sensations.

The Eye and Its Connection to the Brain

The eye has a complex structure consisting of the cornea, lens, retina, and bipolar cells.
The retina is connected to the brain through the optic nerve (second cranial nerve).
The optic nerve exits through the back of the eye, creating a blind spot where the image falls on the site of the optic disk.

Structure and Function of the Retina

The retina has two main types of visual receptors: rods and cones.
Rods are abundant in the periphery, responding to faint light, but are not useful in daylight.
Cones are abundant in and near the fovea, essential for color vision, and more useful in bright light.

Fovea and Periphery of the Retina

Fovea is a tiny area specialized for acute, detailed vision, with nearly unimpeded vision due to the absence of blood vessels and ganglion cell axons.
The periphery is responsible for peripheral vision, with a different type of visual receptor.

Visual Receptors and Photopigments

Photopigments are chemicals that release energy when struck by light, consisting of 11-cis-retinal bound to proteins called opsins.
Photopigments modify the sensitivity to different wavelengths of light.

Theories of Color Vision

The Trichromatic Theory proposes that human eyes only perceive three colors of light: red, blue, and green.
The Opponent-Process Theory suggests that color vision is a result of the interaction between opposing neural processes, creating negative color afterimages.

Color Vision and Color Constancy

Color vision is the ability to recognize colors despite changes in lighting.
Color constancy is the ability to perceive colors as consistent despite changes in lighting conditions.

Color Vision Deficiency

One of the first discoveries in psychology was color vision deficiency, also known as colorblindness.
Color vision deficiency is a condition where individuals have difficulty perceiving certain colors.

Description

Learn about the foundational principles of perception according to Johannes Müller and the Law of Specific Nerve Energies. Explore how the brain codes information based on active neurons and their activity levels, deciphering sensations like light, sound, touch, and more.