Behavioral Neuroscience Exam 2 Study Guide
● identify the roles of visible light, hue, saturation, and brightness in the perception of light
○ Visible Light: (about 400–700 nanometers)
○ Hue: Refers to the color we see
■ Determined by the wavelength of light
● shorter wavelengths = blue/violet
● longer = red
○ Saturation: Refers to the intensity or purity of a color
■ High saturation = vivid, pure color
■ Low saturation = dull or washed-out color (more white light mixed in)
○ Brightness: Refers to how light or dark a color appears
■ Determined by the amplitude (height) of the light wave
● larger amplitude = brighter light
● identify the following structures of the eye – pupil, cornea, lens, retina -- and recognize
their function in visual processing
○ Cornea: Clear outer layer covering the front of the eye
■ Protects the eye and bends (refracts) light to begin focusing it
○ Pupil: Opening in the center of the iris
■ Controls the amount of light entering the eye
● dilates in dim light
● constricts in bright light
○ Lens: Focuses light onto the retina by changing shape (a process called accommodation)
■ Flattens for distant objects
■ Thickens for close objects
○ Retina: Light-sensitive layer at the back of the eye
■ Contains photoreceptors (rods and cones) that convert light into electrical signals
sent to the brain through the optic nerve
● recognize the location and function of rods and cones
○ Rods: Located mostly in the peripheral areas of the retina
■ Responsible for night vision and detecting black, white, and gray
■ Acuity: Low visual acuity (poor detail and no color)
■ Sensitivity: High light sensitivity, can detect single photons
○ Cones: Concentrated in the fovea (the center of the retina)
■ Responsible for color vision and sharp detail
■ Work best in bright light
■ Three types of cones respond to red, green, and blue wavelengths
■ Acuity: High visual acuity (sharp detail)
■ Sensitivity: Low light sensitivity — need bright light to function
● distinguish between the characteristics of central and peripheral vision (including
receptive fields and acuity)
○ Central Vision
■ Small receptive fields (fovea) → precise detail detection
■ Works best in bright light (photopic vision)
○ Peripheral Vision
■ Large receptive fields → less detail, but good at detecting movement
■ Works best in dim light (scotopic vision)
●
,● recognize how stimuli are conveyed to the brain through the optic nerves
○ Light → Retina → Photoreceptors → Bipolar cells → Ganglion cells
■ Ganglion cell axons form the optic nerve
■ At the optic chiasm, fibers from the nasal side of each retina cross to the
opposite hemisphere:
● Left visual field → right hemisphere
● Right visual field → left hemisphere
● identify all parts of the the primary visual pathway for conscious visual perception,
including the roles of the striate and the extrastriate cortex
○ Retina → Optic Nerve → Optic Chiasm → Lateral Geniculate Nucleus (LGN) → Primary
Visual Cortex (V1 or Striate Cortex) = path of conscious vision
○ Lateral Geniculate Nucleus (LGN) – part of the thalamus that acts as a relay station,
organizing and refining visual input
○ Primary Visual Cortex (V1 or Striate Cortex) – located in the occipital lobe; processes
basic features like edges, orientation, color, and movement
○ Extrastriate Cortex (V2, V3, V4, V5/MT) – processes complex visual information; start to
know what's happening in the rest of the body
● recognize how cells in the striate cortex respond to orientation
○ Simple Cells
■ Respond best to bars or edges of a particular orientation (e.g., vertical or
horizontal)
■ Sensitive to both orientation and position
○ Complex Cells
■ Detect motion and direction of movement
○ Hypercomplex (End-Stopped) Cells
■ Respond to specific shapes or lengths of lines and corners or angles
■ Help detect more complex visual features
○ All are found in V1 primary visual cortex
● identify the role of the extrastriate cortex in visual processing, including the dorsal and
ventral streams
○ The extrastriate cortex includes visual areas beyond V1 (such as V2, V3, V4, V5/MT)
○ Processes more complex aspects of vision like form, color, motion, and object recognition
○ Two major processing streams emerge from extrastriate areas:
■ Dorsal Stream (“Where” or “How” Pathway)
● Specializes in spatial location, motion, and action guidance
● Answers questions like:
○ “Where is it?”
○ “How do I interact with it?”
● Damage here → problems with spatial awareness or motion perception
(optic ataxia)
○ Examples:
■ Optic Ataxia: difficulty reaching for or interacting with
objects using visual guidance
■ Akinetopsia: motion blindness — inability to perceive
movement
■ Spatial Neglect: failure to attend to one side of space
(often the left side after right parietal damage)
■ Ventral Stream (“What” Pathway)
● Specializes in object recognition, color, and form
, ● Answers questions like:
○ “What is it?”
○ “Who or what am I seeing?”
● Damage here → problems recognizing faces or objects (visual agnosia
or prosopagnosia)
○ Examples:
■ Agnosias
● recognize how visual information is segregated and combined in the visual system (e.g.
when do neurons only respond to specific parts of the visual field, where are there
neurons that might respond to a particular shape anywhere in front of you)
○ Early in processing (retina & V1):
■ Information is segregated by:
● Location (retinotopic mapping)
● Eye of origin (left or right eye)
● Feature type (color, orientation, motion, depth)
○ Neurons in early visual areas respond to specific parts of the
visual field (small receptive fields)
○ Later in processing (extrastriate cortex, temporal/parietal areas):
■ Information is combined to form a complete perception
■ Receptive fields become larger — neurons may respond to complex shapes or
even entire objects
○ Summary of progression:
■ Retina / LGN: small, simple receptive fields → basic contrast and light detection
■ V1: detects edges, orientation, and movement in specific regions
■ Higher visual areas (V4, IT, MT): integrate details → recognize shapes, colors,
and objects anywhere in view
● identify what symptoms would be associated with brain damage localized to various parts
of the visual system (retina, V1)
○ Retina Damage: Leads to blind spots (scotomas) or complete blindness in the affected
eye or visual field
■ Damage before the optic chiasm affects only one eye; after the chiasm, affects
visual fields of both eyes
○ V1 (Primary Visual Cortex / Striate Cortex) Damage: Causes cortical blindness in the part
of the visual field represented by the damaged area (contralateral side)
■ Example: damage to right V1 → loss of vision in the left visual field
■ Some patients show blindsight — ability to respond to visual stimuli without
consciously perceiving them
● recognize the definitions of agnosia and prosopagnosia
○ Agnosia:
Inability to recognize or identify objects, sounds, or people despite normal sensory
abilities
■ (The brain receives visual input but cannot interpret or name what is seen)
○ Prosopagnosia:
A specific type of agnosia where a person cannot recognize faces, even those of close
friends or family
● what wavelengths and amplitude of visible light mean
○ Wavelength: Determines the color (hue) we perceive
■ Short wavelengths = blue/violet (~400 nm)
■ Long wavelengths = red (~700 nm)
● identify the roles of visible light, hue, saturation, and brightness in the perception of light
○ Visible Light: (about 400–700 nanometers)
○ Hue: Refers to the color we see
■ Determined by the wavelength of light
● shorter wavelengths = blue/violet
● longer = red
○ Saturation: Refers to the intensity or purity of a color
■ High saturation = vivid, pure color
■ Low saturation = dull or washed-out color (more white light mixed in)
○ Brightness: Refers to how light or dark a color appears
■ Determined by the amplitude (height) of the light wave
● larger amplitude = brighter light
● identify the following structures of the eye – pupil, cornea, lens, retina -- and recognize
their function in visual processing
○ Cornea: Clear outer layer covering the front of the eye
■ Protects the eye and bends (refracts) light to begin focusing it
○ Pupil: Opening in the center of the iris
■ Controls the amount of light entering the eye
● dilates in dim light
● constricts in bright light
○ Lens: Focuses light onto the retina by changing shape (a process called accommodation)
■ Flattens for distant objects
■ Thickens for close objects
○ Retina: Light-sensitive layer at the back of the eye
■ Contains photoreceptors (rods and cones) that convert light into electrical signals
sent to the brain through the optic nerve
● recognize the location and function of rods and cones
○ Rods: Located mostly in the peripheral areas of the retina
■ Responsible for night vision and detecting black, white, and gray
■ Acuity: Low visual acuity (poor detail and no color)
■ Sensitivity: High light sensitivity, can detect single photons
○ Cones: Concentrated in the fovea (the center of the retina)
■ Responsible for color vision and sharp detail
■ Work best in bright light
■ Three types of cones respond to red, green, and blue wavelengths
■ Acuity: High visual acuity (sharp detail)
■ Sensitivity: Low light sensitivity — need bright light to function
● distinguish between the characteristics of central and peripheral vision (including
receptive fields and acuity)
○ Central Vision
■ Small receptive fields (fovea) → precise detail detection
■ Works best in bright light (photopic vision)
○ Peripheral Vision
■ Large receptive fields → less detail, but good at detecting movement
■ Works best in dim light (scotopic vision)
●
,● recognize how stimuli are conveyed to the brain through the optic nerves
○ Light → Retina → Photoreceptors → Bipolar cells → Ganglion cells
■ Ganglion cell axons form the optic nerve
■ At the optic chiasm, fibers from the nasal side of each retina cross to the
opposite hemisphere:
● Left visual field → right hemisphere
● Right visual field → left hemisphere
● identify all parts of the the primary visual pathway for conscious visual perception,
including the roles of the striate and the extrastriate cortex
○ Retina → Optic Nerve → Optic Chiasm → Lateral Geniculate Nucleus (LGN) → Primary
Visual Cortex (V1 or Striate Cortex) = path of conscious vision
○ Lateral Geniculate Nucleus (LGN) – part of the thalamus that acts as a relay station,
organizing and refining visual input
○ Primary Visual Cortex (V1 or Striate Cortex) – located in the occipital lobe; processes
basic features like edges, orientation, color, and movement
○ Extrastriate Cortex (V2, V3, V4, V5/MT) – processes complex visual information; start to
know what's happening in the rest of the body
● recognize how cells in the striate cortex respond to orientation
○ Simple Cells
■ Respond best to bars or edges of a particular orientation (e.g., vertical or
horizontal)
■ Sensitive to both orientation and position
○ Complex Cells
■ Detect motion and direction of movement
○ Hypercomplex (End-Stopped) Cells
■ Respond to specific shapes or lengths of lines and corners or angles
■ Help detect more complex visual features
○ All are found in V1 primary visual cortex
● identify the role of the extrastriate cortex in visual processing, including the dorsal and
ventral streams
○ The extrastriate cortex includes visual areas beyond V1 (such as V2, V3, V4, V5/MT)
○ Processes more complex aspects of vision like form, color, motion, and object recognition
○ Two major processing streams emerge from extrastriate areas:
■ Dorsal Stream (“Where” or “How” Pathway)
● Specializes in spatial location, motion, and action guidance
● Answers questions like:
○ “Where is it?”
○ “How do I interact with it?”
● Damage here → problems with spatial awareness or motion perception
(optic ataxia)
○ Examples:
■ Optic Ataxia: difficulty reaching for or interacting with
objects using visual guidance
■ Akinetopsia: motion blindness — inability to perceive
movement
■ Spatial Neglect: failure to attend to one side of space
(often the left side after right parietal damage)
■ Ventral Stream (“What” Pathway)
● Specializes in object recognition, color, and form
, ● Answers questions like:
○ “What is it?”
○ “Who or what am I seeing?”
● Damage here → problems recognizing faces or objects (visual agnosia
or prosopagnosia)
○ Examples:
■ Agnosias
● recognize how visual information is segregated and combined in the visual system (e.g.
when do neurons only respond to specific parts of the visual field, where are there
neurons that might respond to a particular shape anywhere in front of you)
○ Early in processing (retina & V1):
■ Information is segregated by:
● Location (retinotopic mapping)
● Eye of origin (left or right eye)
● Feature type (color, orientation, motion, depth)
○ Neurons in early visual areas respond to specific parts of the
visual field (small receptive fields)
○ Later in processing (extrastriate cortex, temporal/parietal areas):
■ Information is combined to form a complete perception
■ Receptive fields become larger — neurons may respond to complex shapes or
even entire objects
○ Summary of progression:
■ Retina / LGN: small, simple receptive fields → basic contrast and light detection
■ V1: detects edges, orientation, and movement in specific regions
■ Higher visual areas (V4, IT, MT): integrate details → recognize shapes, colors,
and objects anywhere in view
● identify what symptoms would be associated with brain damage localized to various parts
of the visual system (retina, V1)
○ Retina Damage: Leads to blind spots (scotomas) or complete blindness in the affected
eye or visual field
■ Damage before the optic chiasm affects only one eye; after the chiasm, affects
visual fields of both eyes
○ V1 (Primary Visual Cortex / Striate Cortex) Damage: Causes cortical blindness in the part
of the visual field represented by the damaged area (contralateral side)
■ Example: damage to right V1 → loss of vision in the left visual field
■ Some patients show blindsight — ability to respond to visual stimuli without
consciously perceiving them
● recognize the definitions of agnosia and prosopagnosia
○ Agnosia:
Inability to recognize or identify objects, sounds, or people despite normal sensory
abilities
■ (The brain receives visual input but cannot interpret or name what is seen)
○ Prosopagnosia:
A specific type of agnosia where a person cannot recognize faces, even those of close
friends or family
● what wavelengths and amplitude of visible light mean
○ Wavelength: Determines the color (hue) we perceive
■ Short wavelengths = blue/violet (~400 nm)
■ Long wavelengths = red (~700 nm)
