Biopsychology exam 2

Cornea

protective outer clear layer where light first comes through the eye, helps focus light on the retina

Pupil

black part of in the center of the eye which lets the light enter the inner eye and eventually reach the retina

Iris

colored part of the eye that controls the size of the pupil and therefore the amount of light coming in

Lens

disk-like structure in the inner eye which focuses light from the pupil onto the retina

Retina

lined with visual receptors called photoreceptors (rods & cones)

color vision, abundant in fovea

What is the purpose of cones / where are they?

low light vision & movement, abundant in periphery (area outside fovea)

What is the purpose of rods / where are they?

Receive information from bipolar cells, their axons bind together to form the optic nerve

What is the purpose of ganglion cells?

Optic nerve

bundle of ganglion cell axons which send information related to the sensation of vision

Blind spot

The point where the optic nerve leaves the eye, contains no receptors

Parvocellular cells (P cells)

Detects fine details & color. Highly sensitive to color. Small cell bodies.

In/near fovea

Where are parvocellular cells (P cells) located?

Magnocellular cells (M cells)

Detect movement & broad outlines. NOT sensitive to color. Large cell bodies.

Fovea

the central portion of the retina; allows for acute and detailed vision

50+

How many photoreceptors are there per 1 ganglion/bipolar cell?

Cornea -> Pupil -> Lens -> Retina

In what order does light travel through the eye?

Photoreceptors (Rods & Cones) -> Bipolar cells -> Ganglion cells -> Optic Nerve

In what order does light travel through the retina?

Optic chiasm

the point where the two optic nerves (left + right eye) meet letting some visual field information cross over

Left hemisphere

To what hemisphere does right field visual information travel?

Right hemisphere

To what hemisphere does left field visual information travel?

Optic tract

Where does visual information travel after hitting the optic chiasm?

Lateral Geniculate Nucleus (LGN)

Where does visual information travel after hitting the optic tract?

Primary visual cortex (area V1)

Where does visual information travel after hitting the lateral geniculate nucleus (LGN)?

Simple cells

LINE detector cells in the visual cortex. has excitatory (“ON”) and inhibitory (“OFF”) receptive fields for certain object orientations

Complex cells

MOTION detector cells in the visual cortex. large receptive field that cannot be mapped into fixed excitatory (“ON”) or inhibitory (“OFF”) zones

End-stopped/hypercomplex cells

ANGLE detector cells in the visual cortex. large receptive field with a strongly inhibitory area (“OFF”) at one end

Ventral stream

The “WHAT” pathway. Identifies/recognizes objects/shapes.

Where does the ventral stream project?

Projects to area V4, then inferior temporal cortex

Dorsal stream

The “WHERE” pathway. Processes movement/spatial location.

Where does the dorsal stream project?

Projects to area MT (V5), then posterior parietal cortex

may be responsible for color, color constancy & visual attention

What is the purpose of area V4?

Color constancy

the ability to recognize something as being the same color despite changes in lighting (blue/black / white/gold dress)

Perceiving acceleration, deceleration, and absolute speed. Responds to stimuli moving in a particular speed/direction.

What is the purpose of the Middle Temporal Cortex (MT/V5)?

Responding to expansion, contraction, or rotation of a visual stimulus. (Keeping vision consistent with head movement)

What is the purpose of the Medial Superior Temporal Cortex (MST)?

Blindsight

an ability to respond to visual stimuli that the person reports not seeing

Astigmatism

a blurring of vision for lines in one direction, caused by an asymmetric curvature of the eyes (irregular shape of cornea and/or lens)

either the lack of a cone type or by a cone that has abnormal properties

What causes color vision deficiency?

Strabismus

A condition in which the eyes do not point in the same direction (lazy eye)

individuals will focus on moving one eye but not the other, causing cortical cells to strengthen connections with the moving eye and suppress signals from the non-moving weakened eye

What causes strabismus?

Visual agnosia

inability to recognize objects despite satisfactory vision

Prosopagnosia

the impaired ability to recognize faces. Occurs after damage to the fusiform gyrus of the inferior temporal cortex (ventral “what” pathway)

Motion blindness

inability to determine direction, speed, and whether objects are moving. Likely caused by damage in area MT (dorsal “where” pathway)

Amplitude

intensity of the sound wave (loud/quiet)

Frequency

number of compressions/cycles per second (pitch)

Pinna

structure of flesh & cartilage attached to each side of the head (basically just what you see as your ear, the outside)

Tympanic membrane

Vibrates at same frequency as sound waves when struck (eardrum)

Ossicles

Small bones connected to the tympanic membrane which transmit vibrations to the oval window

Oval window

membrane separating the middle and inner ear (wall of cochlea)

Cochlea

snail-shaped structure of inner ear. Contains 3 fluid-filled canals

Hair cells

auditory receptors in the cochlea

Transduction (turning vibrations into neuronal signals)

What is the purpose of hair cells?

Primary auditory cortex (A1)

the destination for most information from the auditory system

processing auditory information (NOT necessary for hearing)

What is the purpose of the primary auditory cortex (A1)?

tonoptic map

A function of the primary auditory cortex (A1), cells of A1 are more responsive to their preferred tones

Conductive deafness

A hearing impairment in the outer or middle ear, occurs if sound waves are not properly reaching the cochlea

Nerve deafness/sensorineural hearing loss

A hearing impairment in the inner ear, occurs from damage to the cochlea, hair cells, or auditory nerve

Tinnitus

Frequent or constant ringing in the ear

Mechanical senses

Respond to pressure, bending, or other physical deformations of a receptor. Examples include audition, vestibular sensation, and somatosensation.

Chemical senses

Respond to tastes, odors, pheromones. Examples include taste and olfaction.

Vestibular sensation

detects the position & movement of the head

in the ear, adjacent to the cochlea

Where is the vestibular organ?

Otoliths

calcium carbonate particles that push against different hair cells. Excite hair cells when the head tilts

Semi-circular canals

filled with a jelly-like substance (endolymph) and hair cells that are activated when the head moves. Involved in the perception of acceleration

Somatosensation

Sensation of the body and its movements (Discriminative touch, deep pressure, cold, warmth,
pain, itch, tickle, and the position/movement of the joints)

detect pressure & high-frequency vibrations on skin (toothbrush, hairdryer, etc.). RAPIDLY adapting (Maximally but briefly responds to a stimulus).

What is the purpose of a pacinian corpuscle?

detect movement across the skin & low-frequency vibrations on the skin (flutter). RAPIDLY adapting (Maximally but briefly responds to a stimulus).

What is the purpose of a Meissner corpuscle?

receptors that respond to static light touch (not moving). SLOW adapting (Firing constantly as long as the stimulus is compressing it)

What is the purpose of Merkel disks?

receptors that respond to skin stretch. SLOW adapting (Firing constantly as long as the stimulus is compressing it)

What is the purpose of Ruffini endings?

Taste

stimulation of taste buds, which contain taste receptors of the tongue

orbitofrontal cortex

Where do taste and smell axons converge?

Papillae

structures on the surface of the tongue that contain the taste buds

every 10-14 days

How often are taste receptors replaced?

Umami, glutamate receptor

What is the fifth primary taste receptor?

Olfaction

Sense of smell - detection & recognition of chemicals that contact the membrane/chemical receptors inside the nose

involuntary muscle movement that specializes in “pushing” (Digestive system, blood vessels, etc.)

What is the purpose of smooth muscles?

large voluntary muscle movement of the body in relation to the environment (Moving arms, legs, diaphragm, etc.)

What is the purpose of skeletal / striated muscles?

Cardiac muscles

heart muscles that have properties of skeletal & smooth muscles

Antagonistic muscles

a group of opposing muscles being either a flexor muscle or extensor muscle

Flexor muscle

a muscle that flexes or raises an appendage

Extensor muscle

a muscle that extends or straightens an appendage

produce fast contractions but fatigue rapidly. Don’t use oxygen for fuel but still need to refuel after fatigue settles in. Example: running

What is the purpose of fast-twitch muscle fibers?

produce less vigorous contractions however they do so without fatigue. These still require oxygen during movement. Example: jogging

What is the purpose of slow-twitch muscle fibers?

Neuromuscular junction

a synapse between a motor neuron and a muscle fiber

Acetylcholine (excitatory) is released. This opens up sodium channels which cause it.

How does a muscle contract?

Proprioceptor

a somatosensory receptor that detects the position or movement of a body part

Muscle spindle

a type of proprioceptor that respond to a muscle being stretched and cause a contraction to the muscle

Stretch reflex

when muscle proprioceptors detect the stretch and tension of a muscle and send signals to the spinal cord in order to contract it

Golgi tendon organ

a proprioceptor which responds to muscle contractions and acts as a brake for the muscle

control of specific areas of the opposite side of the body. It sends the majority of signals to the contralateral body part. It is also active when people intend a movement in which it “orders” an outcome

What is the responsibility of area M1?

integrates vision, audition, and proprioception so we have a representation of the position of the body relative to the world. Damage to this area causes difficulty in coordinating visual stimuli with movement. This area helps with intent to make a planned movement.

What is the posterior parietal cortex responsible for?

This area is active during the planning of movement. It takes the information about position and posture of body in order to organize the direction of the movement in space

What does the premotor cortex do?

This area organizes a rapid sequence of complex movements into a specific order

What is the supplementary motor area responsible for?

This area determines the probable outcome of a movement. It also inhibits movement and impulses

What is the prefrontal cortex responsible for?

Corticospinal tracts

neural pathways from the cerebral cortex to the spinal cord

controls muscles in the LATERAL parts of the body. CONTRAlateral. Axons extend from 1 side of brain to opposite side of spinal cord (controls opposite side of body)

What is the purpose of the lateral corticospinal tract?

controls muscles in the MEDIAL part of the body. contralateral AND ipisilateral. Axons extend from 1 side of the brain to both sides of spinal cord

What is the purpose of the medial corticospinal tract?

Red nucleus

A cluster of neurons in the midbrain, part of the LATERAL corticospinal tract. Involved with motor output signals to fingers/hands/arms

Vestibular nucleus

A cluster of neurons in the medulla, part of the MEDIAL corticospinal tract. Involved with motor output related to balance sensations - equilibrium, posture, head position

Balance and coordination, attention (ability to shift attention / attend to visual stimuli)

What is the purpose of the cerebellum?

Trouble with rapid movements involving aiming/timing

What does damage to the cerebellum cause?