PSY 324 exam 4

Conductive hearing loss (bones) - the types

Otitis media: Inflammation in the middle ear, the middle ear fills with mucus from infection and impairs vibration/amplification of the ossicles

Otosclerosis: Abnormal growth in the middle ear; generally on the stapes. Can have surgery to try and remove the calcification because this will not just go away with medication

Sensorineural hearing (most serious)

• Most often results from damage to the hair cells

• It can also occur if the auditory nerve is damaged

Metabolic hearing loss

Inadequate nutrients/ions delivered to hair cells

• Viruses, medications (cancer drugs), exposure to noise, aging (loose ability to hear high frequencies first - starts as young as 20)

  • Hearing loss increases dramatically in middle age

What are the three ways that we can tell how far away a sound is?

1. The Relative Intensity - the simplest way

   • Sounds hat come from a closer source will be louder than those produced by a farther source

     • this is not the best way because then we make the assumption that the intensity stays the same throughout

     • Another problem is the inverse square law: As distance increases, intensity decreases by a factory equal to distance squared

2. Spectral composition of sounds

   • High frequencies loose energy faster than low frequencies —> results in farther away sounds being perceived as “muddier”

   • Noticeable for fairly large distanced (over 1000 meters)

3. Relative amount of direct vs. reverberant energy

   • When a sound is close most energy is direct

   • When a sound is far away most energy is reverberant

What is timbre and what is its role in sound perception

Timbre: Sounds with the same intensity and pitch are perceived as dissimilar

• Due to different information conveyed by harmonics

• Not just the number of harmonics, but also the intensity of each harmonic

Timbre is also important for distinguishing phonemes, the smallest part of a sound that when put together make words

• Crucial that even if spoken by different people, we are able to hear the same timber quality of the sound to understand the word

What are the five cues that we can use to determine if a sound comes from the same source or not

1. Spatial Separation = The distance between the two sound sources

2. Similarity between spectral qualities = Someone’s voice has specific qualities

3. Temporal Similarity = Consider something from the same source if the timing is similar (timing = rhythm)

4. Timbre = Sound qualities. Different levels of harmonics

5. Onset = Timing. There will be slightly different start times even if you are trying to be at the same time

What is the difference between fast-adapting and slow-adapting tactile receptors

Fast-adapting = Larger in diameter, bursts of action potential, myelinated

Slow-adapting = Small in diameter, continuous action potential

What are Kinesthetic receptors

A type of mechanoreceptor that is located in the muscles, tendons, and joints

• Responsible for helping us understand where our limbs are in space and what kind of movement is occurring (kinesthesia)

What are thermoreceptors and their function

They detect temperature changes in the skin. The receptors respond when you make contact with something that is either colder or hotter than your body temperature

• Also important for the regulation of body temperature. We change our behavior in response to firing of cold and warmth fibers

What are Nocioceptors

They transmit information about noxious (pain) stimulation that can cause damage to skin

• Results in the sensation of pain

• Quick and sharp or long and throbbing

• Pain receptors are also located on internal organs

A-Alpha fibers

myelinated; kinesthetic (proprioceptive) receptors

A-Beta fibers

Myelinated; Mechanoreceptors

A-Delta fibers

Myelinated; thermoreceptors and nocioceptors

C-fibers

Unmyelinated; thermoreceptors and nocioceptors

Tactile Agnosia

Inability to identify objects by touch

• Due to lesions in the parietal lobe of the brain

• Sensory abilities are intact (perceive roughness and weight, etc) but making a connection between them to identify specific objects

Congenital analgesia

Inability to feel pain (born with it)

• Due to a genetic mutation

• May result in overproduction of endorphins in brain OR may result in a lack of functional Na+ channels in spinal cord (preventing the neural transmission)

Odorant

A sensation - A molecule that has specific physiochemical properties, which are capable of being translated by the nervous system into the perception of smell

Odor

Perception - The actual translation of a chemical stimulus into a smell

3 key properties to be perceives:

• Volatile - can float in the air

• Small

• Hydrophobic - repels water

Olfactory cleft

Narrow space in the back of the nose where air flows

Olfactory epithelium

A secretory mucus membrane within the olfactory membrane

What cells make up the olfactory epithelium and what do they do

• Olfactory sensory neurons (OSNs) - Small neurons located just below the mucus layer in the epithelium

• Supporting cells - provide physical and metabolic support cells for OSNs

• Basal Cells - Precursor cells of OSNs

What is the process of smell sensation and how does that information get relayed to the brain

About 7-8 molecules must bind and the neuron must fire about 40 times before the information from the OSN converges onto the glomeruli. Before the smell sensation gets to the primary olfactory cortex it goes to the olfactory bulb.

Anosmia

Complete inability to smell

• Congenital, illness, trauma, toxins, medications, and age

Parosmia

Distorted sense of smell

• Someone with this might find that an odor that is usually pleasant to be awful (rotten)

• Fairly common (3.9%), but can more common with COVID-19