PSY 320 ~ MIDTERM REVIEW

What is transduction?

Transduction is when a sense organ turns physical energy into electrical signals in the nerves.

Where is the cornea and what is its function?

The cornea is at the front of the eye and does most of the focusing of light on the retina

Where is the lens and what is its function?

The lens is behind the pupil and changes shape to help focus on near or far objects

Where is the pupil and what is its function?

Where is the pupil and what is its function?

Where is the retina and what is its function?

The retina is the back surface of the eye and contains rods and cones that turn light into neural signals.

Where is the optic nerve and what is its function?

The optic nerve exits the back of the eye and carries visual information to the brain.

What is the blindspot and why do we have it?

The blindspot is where the optic nerve leaves the retina and there are no receptors, so that spot cannot see.

Where is the fovea and what is its function?

The fovea is in the center of the retina and gives the sharpest, most detailed and color vision

How do the cells in the retina connect and what is the direction that light travels (inside-out)?

Light passes through ganglion cells, then bipolar cells, and finally hits rods and cones. Signals then go from rods/cones to bipolar cells to ganglion cells and into the optic nerve

What are the receptors of the visual system and what input do they receive?

The receptors are rods and cones, and they receive light

What are the main differences between rods and cones?

Rods see in dim light, do not see color, and give poor detail. Cones need bright light, see color, and give sharp detail

What is the difference between sensation and perception?

Sensation is detecting a stimulus, and perception is how the brain interprets that stimulus

How does wavelength relate to color perception?

Different wavelengths of light are seen as different colors, such as longer waves for red and shorter waves for blue

Describe the pathway from eye to brain

Light → rods and cones → bipolar cells → ganglion cells → optic nerve → optic chiasm → lateral geniculate nucleus (LGN) → primary visual cortex (V1)

What is the optic chiasm and what happens there?

The optic chiasm is where the optic nerves meet and some fibers cross to the opposite side, so each hemisphere sees the opposite visual field.

What is the lateral geniculate nucleus (LGN) and where is it?

The LGN is a visual relay in the thalamus that sends visual information to V1

Where is the primary visual cortex (V1)?

V1 is in the occipital lobe at the back of the brain.

How is information from the visual fields represented in V1?

V1 has a map of the visual field, with nearby places in space represented by nearby neurons and a large area for the fovea.

What do cells in primary visual cortex process?

They process edges, lines, orientation, motion, size, color, and contrast

What is the ventral visual stream and what does it do?

The ventral stream goes to the temporal lobe and helps identify what objects are (“what” pathway)

What is the dorsal visual stream and what does it do?

The dorsal stream goes to parietal and frontal areas and helps locate objects and guide movements toward them (“where/how” pathway)

What is visual agnosia and where is the damage?

Visual agnosia is not being able to recognize objects even though you can see them; it usually comes from damage in temporal “what” areas.

What is prosopagnosia and where is the damage?

Prosopagnosia is “face blindness,” usually from damage to the fusiform face area in the inferior temporal cortex.

What is akinetopsia and where is the damage?

Akinetopsia is motion blindness (trouble seeing movement), usually from damage in motion areas of the dorsal pathway.

What is a critical period and why is it important for vision?

A critical period is an early time when normal visual input is needed for normal vision development. If vision is blocked then, the loss can be permanent.

What are sound waves?

Sound waves are vibrations of air molecules

How does amplitude relate to how something sounds?

Amplitude is how big the wave is and is heard as loudness

How does frequency relate to how something sounds?

Frequency is how many waves per second and is heard as pitch

What are the main parts of the outer ear and what do they do?

The pinna and ear canal collect and funnel sound into the ear.

What are the main parts of the middle ear and what do they do?

The eardrum and ossicles vibrate and amplify sound.

What are the main parts of the inner ear and what do they do?

The cochlea has hair cells that turn sound into neural signals.

What are the ossicles and what is their function?

The ossicles are three tiny bones (malleus, incus, stapes) in the middle ear that amplify sound and send it to the cochlea

What are the receptor cells in hearing?

Hair cells in the cochlea

Where are hair cells located and how do they work?

They are on the basilar membrane inside the cochlea. Fluid movement bends them and makes them send signals to the auditory nerve.

What is Bekesy’s Place Theory?

It says different pitches vibrate different places on the basilar membrane: high pitches near the base, low pitches near the apex

How is the cochlea organized for pitch?

It is tonotopic, with high frequencies at the base and low frequencies at the apex

How is primary auditory cortex (A1) organized for pitch?

A1 is also tonotopic, with different areas best for different pitches

What is the pathway from hair cells to primary auditory cortex?

Hair cells → auditory nerve → cochlear nucleus → superior olive → inferior colliculus → medial geniculate nucleus (MGN) → A1 in the temporal lobe

From the cochlea, where does information go first in the brain?

It goes from the cochlea to the auditory nerve and then to the cochlear nucleus.

Where are quick sound responses processed?

In brainstem and midbrain areas like the superior olive and inferior colliculus.

What are the three key structures in SONIC MG for sound and where are they?

Superior olive (pons), inferior colliculus (midbrain), and medial geniculate nucleus (thalamus

Where does most auditory information cross to the other side of the brain?

At the level of the pons

How much auditory information crosses over

About 80% crosses; about 20% stays on the same side

Where is the primary auditory cortex?

In the temporal lobe.

What does the ventral auditory pathway do?

It helps recognize what sounds are, like speech or pitch patterns.

What does the dorsal auditory pathway do?

It helps find where sounds come from and guide actions based on sound.

What is conductive deafness?

Hearing loss from problems in the middle ear that stop sound from getting to the cochlea

What is nerve (sensorineural) deafness?

Hearing loss from damage to the cochlea, hair cells, or auditory nerve.

What is tinnitus?

Ringing or buzzing in the ears

When is a cochlear implant helpful?

When hair cells are damaged but the auditory nerve still works.

What must be intact for a cochlear implant to work?

The auditory nerve

What is the vestibular system important for?

It helps with balance, sensing head movement, and knowing where your body is in space

What are the main parts of the vestibular system?

Three semicircular canals and two otolith organs (utricle and saccule)

Where are the vestibular parts located and what do the semicircular canals do?

They are in the inner ear, above the cochlea. The semicircular canals sense head rotation

What are the two otolith organs and what do they do?

The utricle senses horizontal head movement/tilt, and the saccule senses vertical movement/tilt

What are the receptor cells in the vestibular system?

Hair cells

What kind of information do vestibular hair cells detect?

They detect head movement and changes in head position

What is the name of the 8th cranial nerve?

The vestibulocochlear nerve (auditory-vestibular nerve

What does endogenous mean?

It means produced inside the body, not from the environment

What is the average length of a human circadian rhythm?

About 24 to 25 hours

Where is the control center of circadian rhythms?

The suprachiasmatic nucleus (SCN) in the hypothalamus

How do the PER and TIM proteins help control the sleep cycle?

Their levels rise and fall in a daily pattern; high levels make you sleepy and light can lower them and reset the clock

How does light affect our sleep?

Light resets the circadian clock and can delay or advance sleep depending on when you see it

Which neurotransmitters are important for wakefulness and alertness?

Acetylcholine, glutamate, histamine, orexin, and norepinephrine.

Which neurotransmitters are important for promoting sleep?

GABA and adenosine

What does melatonin do?

It makes you feel sleepy and signals that it is time for sleep

What releases melatonin and in response to what?

The pineal gland releases melatonin in response to signals from the SCN based on light and dark

How does light reset the SCN and why does this matter for jet lag and shift work?

Light signals from the eyes reset the SCN. Sudden changes in light schedule cause jet lag and make shift work hard to adjust to

What is the retinohypothalamic pathway and what does it do?

It is a pathway from the retina to the SCN that carries light information to reset circadian rhythms

How does caffeine work?

It blocks adenosine receptors so adenosine cannot make you sleepy as strongly.

What is an EEG and what does it measure?

EEG is a test that measures electrical activity in the brain and shows brain wave patterns

What is REM sleep

Rapid eye movement sleep with active brain, vivid dreams, and muscle paralysis

What is Non-REM sleep?

The sleep stages 1 through 4, from light to deep sleep, with slower brain waves.

What are the Non-REM sleep stages?

Stage 1 (very light), Stage 2 (light/moderate, spindles and K-complexes), Stages 3/4 (deep slow-wave sleep)

During which stage are you least responsive to external stimuli?

Stage 4 deep slow-wave sleep.

How do we cycle through sleep stages during the night?

We move through Non-REM and REM in cycles of about 60–90 minutes, repeated several times.

Which part of the night has the most Non-REM sleep?

The first part of the night has more deep Non-REM (Stages 3/4).

What are key characteristics of REM sleep?

Active brain, irregular heart rate and breathing, vivid dreams, rapid eye movements, and muscle paralysis

Why do we sleep?

o save energy, allow the body and brain to repair themselves, and to help with memory and learning.