Ch 4

Question 1

Sound

Answer 1

Changes in air pressure as a result of displacement of air molecules, creating vibrations in the air. Sound waves are sinusoidal (having the form of a sine).

Question 2

Fundamental frequency (f0)

Answer 2

àMost powerful) The frequency at
which sound waves vibrate. Very energetic, meaning that they still have
power after the signal decomposes.

Question 3

Harmonics

Answer 3

Component of a frequency wave. The fundamental frequency × an integer (1

Question 4

The human ear is sensitive for frequencies ranging between

Answer 4

20 Hz and 20.000 Hz

Question 5

The Peripheral Auditory System

Answer 5

a. External ear
b. Middle ear
c. Oval window
d. Internal ear
e. Cochlea
f. Basilar membrane

Question 6

External ear

Answer 6

Collect and focus sound energy

Question 7

Middle ear

Answer 7

Sound waves vibrate on the eardrum (= tympanic membrane), which moves the three tiny bones connected to it (malleus, incus, stapes), which amplifies sound energy.

Question 8

Oval window

Answer 8

Where the stapes connects to the cochlea (in internal ear).

Question 9

Internal ear

Answer 9

Consists of cochlea, basilar membrane, stereochillia, apex

Question 10

Cochlea

Answer 10

Consists of three chambers filled with fluid

Question 11

Basilar membrane

Answer 11

inside cochlea)àembedded hair cells (tips are called stereocilia) of which their movement causes an action potential.

Question 12

Hair cells move depending on frequency

Answer 12

base) close to oval window= high frequency

apex) end of cochlea= low frequency.
Low frequencies travel far

Question 13

auditory nerve

Answer 13

Signal from hair cells travel to brain
a. Cochlear nucleus
b. Superior olivary complex: Combines signals from both ears
c. Nucleus of lateral lemniscus
d. Inferior colliculus : signal integration.
- frequency recognition.
- pitch discrimination
e. Medial geniculate complex : Relay between inferior colliculus and auditory cortex (same as LGN in vision
f. Auditory cortices : Primary (A1) and secondary
(A2) auditory cortex

Question 14

tonotopic organisation

Answer 14

Different parts of the cortex process different frequencies, with frequencies between 500 and 5000 Hz occupying the largest space because evolutionarily important sounds are within these frequencies.

Question 15

Loudness

Answer 15

Has to do with air pressure and the amplitude of a wave. Interacts with frequency; perception of loudness doesn’t always depend on the physical properties, like brightness

Question 16

Pitch

Answer 16

The frequency of a wave (Hz). Interacts with harmonics; brain creates the fundamental frequency, so the pitch we experience may be different from the true frequency.

pitch experienced in a harmonic series is the
pitch of the fundamental frequency

When you present all the
other stimuli (all missing
the fundamental
frequency), they are
experienced with the same
pitch. The pitch you
experience is that of the
largest common divisor

Question 17

Timbre

Answer 17

How we can distinguish a piano from a violin that are playing at the same pitch and loudness

Question 18

> 3kHz

Answer 18

Interaural time difference

For frequencies greater than 3 kHz. The head creates an acoustic shadow (an obstacle for high frequencies) and intensity differences. This means that a stimulus directed to the left ear will cause a stronger reaction from the left lateral superior olive (LSO) and inhibit activity in the right LSO

Question 19

> 3kHz

Answer 19

For frequencies below 3 kHz. The speed of sound is slow and with the distance between the ears, the maximum difference can be 700 microsecs. The smallest difference we can detect is 10 microseconds, which coincides with how accurately we can determine the location of a sound source, about 1 degree on the horizontal field

Neurons in the medial superior olive (MSO) are coincidence detectors, meaning they detect sound inputs that occur at the same time. Axons projecting from the cochlear nucleus vary in length, creating delay lines. Action potentials are generated at different times from each ear, and thanks to the varying lengths, it is possible for the signal from the left and right ear to arrive in the MSO at the same time. The MSO responds most strongly to coincident arrivals

Question 20

tactile perception

Answer 20

pressure, vibration, tension, and touch

Question 21

specialized receptors

Answer 21

Tactile perception is initiated by a variety of
receptor types in the skin and subcutaneous
tissues. Each receptor is specialized to a
different category of mechanical force.
The quality of the perception (what, where)
depends on the receptors being stimulated and
where they project to in the brain

— root hair plexus (touch)
— ruffini endings (pressure)
— pacinian corpuscles (pressure
— meisser corpuscles (touch)

Some areas, such as
the fingertips, have a
high density of
receptors (with small
receptive fields; 1-2
mm).
Other areas, such as
the forearm, have less
receptors with larger
receptive fields
(several centimetres)

Question 22

root hair plexus

Answer 22

touch

Question 23

ruffini endings

Answer 23

respond to skin stretch

Question 24

Meissen corpuscles

Answer 24

low frequency vibrations: small receptive fields

Question 25

Pacinian corpuscles

Answer 25

high frequency vibrations

Question 26

Path of signal cutaneous system

Answer 26

Dorsal root ganglion -> Spinal cord —> Thalamus —> Ventral posterior nuclear complex —> Primary somatosensory cortex (S1)

Question 27

Nociceptive System

Answer 27

Free nerve endings that receive pain

Perceives pain and temperature. Pain is created in the brain; it is not a quality of an object

Question 28

The Placebo Effect

Answer 28

When a placebo is administered instead of a painkiller, the same brain network is activated to alleviate pain.

the placebo response could be blocked by naloxone if it was induced by strong expectation cues

Opioid antagonists also block effect of placebos

Question 29

Olfactory epithelium

Answer 29

A sheet of receptor neurons in the nasal cavity.
Each neuron contains just one receptor protein. Different types of odor molecules bind to specific receptors. The perception of scent is the combination of different odor molecules on different receptors.

Question 30

The Olfactory System

Answer 30

Receptor neurons —> Olfactory nerve —> Olfactory bulb

Question 31

Taste cells

Answer 31

determine the identity, concentration and
hedonic quality (pleasantness or unpleasantness) of a substance.
Receptors for bitterness, sweetness, saltiness, and sourness are unevenly distributed.