Hearing, smell, and taste Flashcards
Primary cortex
inputs from the thalamic relay nuclei
Secondary cortex
inputs from primary cortex and other areas of secondary cortex
Association cortex
inputs from many parts but mainly from secondary sensory cortex
Functional segregation
different parts of the same level are responsible for different functions
Parallel processing
different areas of the same level will analyze different aspects of the same stimuli
Hierarchical organization
specificity and complexity increases as you move up the levels
What is the path for sound?
outer ear, tympanic membrane, three ossicles, oval window, cochlea, organ of corti, cilia, auditory nerves, cochlear nuclei, superior olives, cross over to medial lemniscus, inferior colliculi
Amplitude
loudness
frequency
pitch
complexity
timbre
Fourrier analysis
the breakdown of complex frequencies to analyze independent wave forms
Cochlea
curled, shell-like organ
Fluid waves move through it, moving two thin membranes,
movement of these membranes is detected by cilia of haircells
How are cilia attached?
they are attached together by a tip link, stretching the tip link causes ion channels to open and depolarize the neurons
Tonotopic representation
membrane of cochlea vibrate by frequency
closer to oval window, higher frequency
farther from oval window, lower frequency
loud sounds generate larger vibrations
Cochlear implant
consists of electrodes connecting to the cochlea, a speaker mounted behind the ear
the waves of sound are detected by the speaker and converted by the electrodes into signals for neurons
How do we tell where sound comes from?
phase differences, intensity differences, timbre changes
Phase differences
the time difference for sound waves to reach the cilia in one ear vs another
detected by medial olivary nuclei
Intensity difference
detects higher frequency
lateral olivary nuclei detects differences in sound frequencies
Timbre differences
sounds at different elevation have different timbres which is used by the ear to determine where sounds are coming from
cochlear nuclei is important for timbre differences
What does the inferior colliculi do in relation to localization of sound
it puts together information from the lateral and medial olivary nuclei as well as the cochlear nuclei and sends information to the thalamus and onto the auditory cortex
Auditory cortex
contains columns that respond to the same frequency
complex tones activate it better than pure tones
organized tonotopically
contains anterior (what) and posterior (where) streams
What is the pathway for olfactory senses?
receptors at nasal cavity interpret it, send it through axons pass the cribriform plate and to the Glomerulus where similar smells are consolidated and then sent to the mitral cells which get sent to the piriform cortex and then to the amygdala or the thalamus
Lateral inhibition
when one type of glomerulus is heavily activated, it will inhibit other neurons
this keeps noise in smelling down
some smells overpower others
Anosmia
Lack of ability to smell
Cacosmia
everything smells like species
Hypersomia
sense of smell is exaggerated
Phantosmia
Hallucinated smells, often unpleasant
What are the five taste chemicals
bitter, sour, sweet, umami, salty
Taste buds
located around papillae
chemoreceptors are on cilia of taste bud cells
What are sour and salty detected by?
ion channels
What are umami, sweet and bitter detected by?
g proteins
How do taste buds send information
through facial, vagus, and glossopharyngeal nerves
What is the path for taste?
taste buds, facial/vagus/glossopharyngeal nerves, solitary nucleus, projects ipsilaterally to thalamus, and then to insular cortex
Dietary neophobia
an aversion to foods foreign to them
used to prevent from consuming spoiled food or poison
