Chapter 7 Vision Flashcards

Flashcards for Chapter 7, covering vision-related terms for exam review.

Transduction

Transforming sensory info into neural signals

Sensation

Process of bringing information into neural CNS from the environment for processing

Perception

Process of interpreting sensory signals sent to the brain

Bottom-up processing

Combines simple meanings to construct more complex meanings

Top-down processing

Uses knowledge and expectation to interpret meaning

Retina

Layer of neurons that turns light into neural signal

Cornea

Outer layer of eye

Photoreceptors

Sensory neurons in retina

Rods

Any wavelength

Cones

Different varieties which respond to different wavelengths

Bipolar Cells

Where neurotransmitters from photoreceptors synapse

Ganglion Cells

Where bipolar cells connect & where the optic nerve forms

Horizontal Cells

Contacts receptor & bipolar cells

Amacrine Cells

Contact bipolar & ganglion cells

Scotopic System

Rod-based System

Photopic System

Cone-based System

Dark current

Rods are constantly depolarized by continuous flow of sodium in cell

Pupil

Opening in iris

Iris

Colorful circles that provides opening for pupil

Visual Field

Area you can see without moving your head

Visual acuity

Sharpness of vision

Fovea

Fine structure of retina

Blind Spot

Nasal side of the fovea where blood vessels and ganglion cell axons leave the eye

Optic nerve

Each human optic nerve divides in half

Optic chiasm

Opposite sides cross at the chiasm

Lateral geniculate nucleus

Axons of LGN neurons form optic radiations

Estrastriate cortex-

Visual cortical areas outside the striate cortex

Grandmother Cells

respond specifically to one thing

Spatial-frequency model

Visual system analyzes the number of cycles light-dark patches in any stimulus

V2

Adjacent to V1. Respond to illusionary contours

V4

Strongest responses to frequency gratings. Some can give stronger response to concentric & radial stimuli. Strong response to color differences

V5 Area MT

Medial temporal area V5 Perception of motion and direction.

Ocular dominance

Respond to one eye or the other

Orientation columns

Respond to lines of the same angle

Hypercolumns

Respond to complete rotation of 180 degrees

Brightness

Varies from dark to light

Hue

Varies continuously through blue, green, yellow, orange, and red

Saturation

Varies from rich full colors to grey

Trichromatic hypothesis

Blue sensitive, Green sensitive, Red sensitive

Opponent process hypothesis

Three opposite pairs of colors: Blue vs yellow, Green vs red, Black vs white

Dorsal Stream

Specializes in processing motion

Ventral Stream

Specializes in face and object recognition

Dichromacy

Having only 2 photopigments

Monochromacy

Only see black

Anomalous trichromacy

One of the 3 types of cones is less sensitive to light

Amblyopia

Poor acuity in 1 eye though eye/retina are normal

Anopia

blindness in 1 eye