Hearing II
Distance
Elevation
Azimuth (left-right)
What is the spatial map of smells in the olfactory bulb called?
Odotopic map
How does the depth of touch receptors relate to the size of their receptive fields?
What are the cells called that allow animals to camouflage?
Chromatophores
Which sense does not go through the thalamus?
Smell
Describe how spectral cues work and what part of the auditory system is involved
The pinna causes sounds to bounce around differently depending on their elevation
This changes the pattern of spectrum (distribution) of frequencies that reach each ear from different locations
What are the bumps on the tongue called, and which parts of the tongue contain taste buds?
Papillae (which contain taste buds)
The perimeter and the back has taste buds, the center does not
What are the 2 pathways for the somatosensory signal in the spinal cord?
1. signals related to sensing limb position (proprioception) and perceiving touch
2. temperature and pain signals
Name 2 properties of echolocation sound waves in bats
- High frequency: ultrasonic (higher than the limits of human hearing)
- Very loud: as loud as some types of gunshots (up to 130dB)
Describe why different cultures hear different phonemes, and the neural mechanisms
•Selective rearing: Our brain develops to hear those specific sounds
•Neurons in different auditory cortex regions respond to different phonemes
Describe direct sound, indirect sound, and the precedence effect
Direct sound: the soundwaves that reach you directly from the source
Indirect sound: the soundwaves that reach you after reflecting off surfaces
Precedence effect: we perceive the sound as coming from the source that reaches our ear first
Describe how flavor is generated
Combination of taste and smell
Smells travel from mouth to olfactory mucosa via the retronasal route
Oral capture makes it seem like signals are coming from the mouth
Bimodal neurons in the orbitofrontal cortex respond to the combination of smell and taste of a specific food
What are 3 things that are processed by the somatosensory system?
Touch sensation
Body perception
Motor actions
Describe how echolocation sounds are sent and received in dolphins
Dolphins produce sound within their noses and send it through a “waxy melon” on their head, then receive the sounds through their lower jaws
Describe what simultaneous grouping is, and the specific cues
Simultaneous grouping: how we can hear simultaneous sounds as coming from different sources
Location: we can separate sound sources based on localization cues like ITD and ILD
Onset synchrony: if two sounds start at slightly different times, it tells us that they likely came from different sources
Timbre and pitch: Sounds that have the same timbre and pitch range are often produced by the same source
Describe the two binaural cues
Interaural level difference (ILD): the difference in the sound pressure level (amplitude) of sounds reaching each ear
Interaural time difference (ITD): the time difference between when a sound reaches the left ear vs right ear
Describe the path of taste starting with the taste buds
Taste bud contains ~50-100 taste cells
Taste cells (receptors for taste) have tips that protrude into taste pore
Taste cell sends signals to various nerves, then the nucleus of the solitary tract
Then the thalamus
Then insula and frontal operculum
What is cortical magnification with respect to touch?
•More cortical area is devoted to areas that sense a lot of detail
•E.g., fingers, lips
Describe the anatomical aspects of electroreception, and how the electric field is used for sensing different types of objects
Electric organ: creates an electrical field around its body
Electroreceptors: Receptors in tiny pits on their skin that detect changes in electric fields
When an object is near the fish, it changes the current flow around it depending on how the object's conductivity compares to water's conductivity
Describe what sequential grouping is, and the specific sequential grouping cues
Sequential grouping: How we perceive a sequence of sounds as being from a single source
Presentation rate: sounds presented very quickly one after another are more likely to be grouped
Similarity of pitch: consecutive sounds that are similar in pitch are usually grouped together
Auditory continuity: Sounds that stay constant or change smoothly are usually produced by same source
Experience: we can recognize familiar streams of sounds, like songs we know, even with a lot of disruption
Phonemic restoration effect: we often don’t notice missing phonemes if they’re filled in by noise
Describe the path of odorants from the air to the secondary olfactory area
Odorants go into the nasal cavity
Then stimulate olfactory receptors in the olfactory mucosa
Then they send their signals to the glomeruli in the olfactory bulb
Which sends signals to the piriform cortex
Then the orbitofrontal cortex
Describe 4 cognitive factors that influence pain, and how they're biologically mediated
- Expectations, including placebo and nocebo
- Attention/distraction
- Emotion
Caused by changes in the release of endorphins to specific parts of the body
Describe the two mechanisms of magnetoreception, and which sensory system they are processed through
Radical pairs mechanism: many birds have magnetically sensitive chemicals formed by light hitting specific proteins in their retinas
•Thought to be processed by visual system
Iron oxide mechanism: many birds have cells in their upper beaks that are microscopic biological compasses
•Sent to the brain via trigeminal nerve, which usually senses temperature, pain, and touch stimuli in the face