Lecture 10 Flashcards
We detect the source of continuous low-pitched sounds by means of what
phase differences
the ears detecting compressed air at the same time? If so, what
the source must be equidistant from the two ears (coming from either right infront, below or above)
The auditory system can identify phase differences of sound waves under 800 Hz, because why
these sound waves have a
half wavelength that is larger than the dimension of the head.
We detect the source of high-pitched sounds how
by analyzing differences in loudness between the ears. (High frequency sounds are significantly dampened as they pass through our heads.)
Most sound waves bounce off folds and ridges of pinna beforewhat
entering ear canal
Most sound waves bounce off folds and ridges of pinna before entering ear canal
• Depending on angle at which sound waves strike these folds and ridges, what can happen
different frequencies will be enhanced or attenuated (i.e. the timbre will change).
Pattern of reflections will change with location of source of sound which will do what to timbre
which will alter timbre of the sound that is perceived
Individual must LEARN to recognize subtle changes in timbre of sounds that originate where
in locations in front of head, behind it, above it, or below it
do we automatically know where sound is in relation to us (from birth?)
no, we have to learn
The fundamental frequency of human speech is what
85-180 Hz for men and 165-255 Hz for women, but the abundance of overtones can give the impression of the fundamental tone
explain how the cochlear implant works
Typically 20-24 electrodes are positioned along the length of the cochlea
Understanding human speech is often best when frequency positions corresponding to 250 Hz to 6500 Hz are stimulated
explain the steps FROM THE EAR TO PRIMARY AUDITORY CORTEX
- The organ of Corti sends auditory information to the brain via the cochlear nerve.
- These axons synapse in the dorsal and ventral cochlear nuclei in the medulla, where copies of the signal are made to be analyzed in parallel ascending paths.
- Axons from the cochlear nuclei synapse in the superior olivary nuclei in the medulla and the inferior colliculi in the midbrain, both of which help localize the source of sounds.
- Axons from the inferior colliculi synapse in the medial geniculate nucleus of the thalamus, which in turn relays the information to the …
- Primary auditory cortex in the tempora llobe
The organ of Corti sends auditory information to the brain via what
the cochlear nerve.
- The organ of Corti sends auditory information to the brain via the cochlear nerve.
- These axons synapse in the dorsal and ventral cochlear nuclei in the medulla, where what happens
where copies of the signal are made to be analyzed in parallel ascending paths.
Axons from the cochlear nuclei synapse in where
the superior olivary nuclei in the medulla and the inferior colliculi in the midbrain, both of which help localize the source of sounds
Axons from the inferior colliculi synapse in where
the medial geniculate nucleus of the thalamus, which in turn relays the information to the …
Axons from the inferior colliculi synapse in the medial geniculate nucleus of the thalamus, which in turn relays the information to the …
Primary auditory cortex in the temporal lobe
Like the basilar membrane, the primary auditory cortex is also organised according to what
frequency
Like the basilar membrane, the primary auditory cortex is also organised according to frequency. Different parts of the auditory cortex respond best to what
to different frequencies
Like the basilar membrane, the primary auditory cortex is also organised according to frequency. Different parts of the auditory cortex respond best to different frequencies.
This organisation where the different frequencies of sound are analyzed in different places of the auditory cortex, is known as what
tonotopic representation
what is tonotopic representation
where the different frequencies of sound are analyzed in different places of the auditory cortex
Primary auditory cortex (core region) is where
in the upper section of the temporal lobe, mostly hidden in the lateral fissure
The belt and parabelt regions refer to what
auditory association cortex.
Like visual information, auditory information is analyzed in what kind of streams
“where” and “what” streams.
The posterior (dorsal) auditory pathway is involved in what
sound localization
The posterior (dorsal) auditory pathway is involved in sound localization. This pathway meets up with what
the “where” vision pathway in the parietal cortex
The anterior auditory pathway goes into the frontal cortex, where what happens
some analysis of complex sounds occur (the “what” are you hearing pathway).
Music and language are special, complex forms of auditory processing, and brain damage in auditory association cortex can cause very specific types of what
auditory agnosia
Music and language are special, complex forms of auditory processing, and brain damage in auditory association cortex can cause very specific types of auditory agnosia.
• For example, the basic underlying beat in music is processed where
in the right auditory cortex
harmony (overtones) is processed where
in the inferior frontal cortex
Particular combinations of musical notes can be perceived as happy, sad, pleasant, unpleasant, consonant, dissonant, etc. This information is processed in the same or different place as auditory info?
separately from other auditory information
what is Amusia
the inability to perceive or produce melodic music.
People with amusia might be unable to do what
sing or recognize the happy birthday song.
can People with amusia often converse and understand speech.
yes
can people with amusia recognize environmental sounds
yes
can people with amusia recognize emotions conveyed in music
They can even recognize the emotions conveyed in music, but they will typically be unable to tell the difference between consonant music (pleasant sounding harmony) and dissonant music (unstable, transitional), even though these sounds can alter their emotional state.
what does the Vestibular system do
detects gravity and angular acceleration of the head
what does the cochlea do
detects sound
does the vestibular system produce any readily definable, conscious sensation
no
The vestibular system does not produce any readily definable, conscious sensation. Instead, it does what
maintains your upright head position, organizes your balance, and corrects eye movements to compensate for head movements
what are the Vestibular sacs (VESTIBULAR SYSTEM)
a set of two receptor organs in each inner ear (utricle & saccule) that detect changes in the tilt of head (gravity)
what are the Semicircular canals (VESTIBULAR SYSTEM)
three ring-like, fluid-filled structures that detect changes in head rotation (angular acceleration)
what is the Cupula (VESTIBULAR SYSTEM)
gelatinous mass found in the ampulla of the semicircular canals; moves in response to the flow of fluid in canals
The utricle & saccule in the vestibular sac respond to what
the force of gravity and inform the brain about the head’s orientation
what does the The somatosensory system do
provides information about touch, pressure, temperature, and pain, both on the surface of the skin and inside the body.
There are three interacting somatosensory systems what are they
the cutaneous senses the proprioceptive (kinesthesia) the interoceptive system
what does the the cutaneous senses do
(skin senses) make up the exteroceptive
system and responds to external stimuli applied to the skin (e.g. localized touch)
what does the the proprioceptive (kinesthesia) system do
monitors information about the position of the body, posture and movement (e.g., the tension of the muscles inside the body)
what does the interoceptive system do
(organic senses) provides information about conditions within the body and is responsible for efficient regulation of its internal milieu (e.g. heart rate, breathing, hunger, bladder)
The cutaneous senses (skin) encode different types of what
external stimuli
what are the different types of external stimuli the skin encodes
vibrations -
pressure
- temperature
- pain
when do vibrations occur
occur when we move our fingers across a rough
surface
what s pressure caused by
is caused by mechanical deformation of the skin
what I temperature produced by
is produced by objects that heat or cool the skin
what is pain caused by
can be caused by many different types of stimuli, but primarily tissue damage
The outermost layer of skin is called what
epidermis (“above dermis”)
The outermost layer of skin is called epidermis (“above dermis”). Cells here get oxygen from what
the air (not the blood)
the middle layer of skin is called what
dermin
the deepest layer of skin is called what
the hypodermis (or subcutaneous, “below the skin”)
Sensory receptors are scattered where in the skin
throughout the layers
what is Glabrous skin
‘hairless’ skin (e.g. palms of hands and feet)
what are Free nerve endings
primarily respond to temperature and pain
where are Meissner’s corpuscles found
found in glabrous skin
what do Meissner’s corpuscles do
They detect very light touch and localized edge contours (brail-like stimuli).
Pacinian corpuscles do what
respond to skin vibrations
Ruffini corpuscles do what
are sensitive to stretch and the kinesthetic sense of finger position and movement
Merkel’s disks respond to what
local skin indentations (simple touch)
There are two categories of thermal receptors what are they
those that respond to warmth and those that respond to coolness
Information from cold sensors is conveyed to CNS by what
thinly myelinated A? fibers
Information from warmth sensors is conveyed by what
unmyelinated C fibers
The receptor proteins that are sensitive to temperature can also be activated by what
ligands (e.g., capsaicin activates heat receptors and menthol activates cold receptors)
aka if you put these portents on skin they will feel cold or warm because they will activate the receptor proteins
Pain sensation, like temperature sensation, is mediated by what
free nerve endings in the skin
There are many types of pain receptor cells (usually referred to as what
nociceptors, or detectors of noxious stimuli)
There are many types of pain receptor cells (usually referred to as nociceptors, or detectors of noxious stimuli)
• One type is the high-threshold mechanoreceptors (pressure receptor cells), which are what
free nerve endings that respond to intense pressure, like something striking, stretching, or pinching the skin
There are many types of pain receptor cells (usually referred to as nociceptors, or detectors of noxious stimuli)
• One type is the high-threshold mechanoreceptors (pressure receptor cells), which are free nerve endings that respond to intense pressure, like something striking, stretching, or pinching the skin
• Other types of free nerve ending appears to respond to what
extreme heat (or the presence of chemicals such as capsaicin, the active ingredient in chili peppers).
Axons from the skin, muscles and internal organs enter the CNS via what
spinal nerves (e.g. dorsal root ganglia).
1.
Highly localized information (e.g. fine touch) ascends ipsilaterally through what
the dorsal column of the white matter of the spinal cord. The first synapse in this pathway is in the medulla. From there the information crosses over to the contralateral side
Poorly localized information (e.g., crude touch, temperature, and pain) immediately does what
crosses over in the spinal cord and the first synapse is there. This information then ascends through the spinothalamic tract.
1.
Highly localized information (e.g. fine touch) ascends ipsilaterally through the dorsal column of the white matter of the spinal cord. The first synapse in this pathway is in the medulla. From there the information crosses over to the contralateral side.
Poorly localized information (e.g., crude touch, temperature, and pain) immediately crosses over in the spinal cord and the first synapse is there. This information then ascends through the spinothalamic tract.
All of this information meets up in the what
medial lemniscus where it ascends to the ventral posterior nucleus of the thalamus and then the primary somatosensory cortex.
what is the thermal grill illusion
if you have 2 bars warm and 2 cool, and place a hand on them at the same time, the brain gets confused and overwhelmed and will think the hand is burning when it is not!
When electrical stimulation is applied to various sites on primary somatosensory cortex, patients report what
somatosensory sensations in specific parts of their bodies
aka they report that they are being touched somewhere when in reality they are just having a part of their primary somatosensory touched
The relationship between cortical stimulations and body sensations is reflected in what
a somatotopic map of the body surface
The somatopic map is also referred to as what
the somatosensory homunculus (“little man”)
think about the oddly shaped man
basically, the brain maps out the body based on how much sensation it can feel (the thumb has as much as an entire foot)
Patients with tactile (Somatosensory) agnosia have trouble doing what
identifying objects by touch alone.
Patients with tactile agnosia have trouble identifying objects by touch alone. However, they are often able to do what
draw an object they are touching, without looking at it, and they can sometimes identify objects from their drawings
people with Somatosensory Agnosia-- When touching an object, people might think this is that: - pine cone -> brush - ribbon -> rubber band - snail shell -> bottle cap These patients can often do what
draw objects when touched but they cannot recognize them by touch alone
explain the Phantom limb
Phantom limb is a form of pain sensation that occurs after a limb has been amputated.
Amputees report that the missing limb still exists and that it often hurts.
One idea is that phantom limb sensation is due to confusion in the somatosensory cortices (primary and association). The brain gets nonsense signals (in part from the cut axons) and it has difficulty interpreting them
The olfactory system is specialized for what
identifying specific molecules.
Things that have odors (known formally as odorants) consists of volatile substances that have molecular weight in range of what
approximately 15 to 300
Almost all odorous compounds are what
lipid soluble and of organic origin. However, many substances that meet these criteria have no odor at all.
what is the Olfactory epithelium
the tissue of the nasal sinus that sits underneath the skull (the cribriform plate) and contains olfactory receptors cells. Each olfactory cell expresses only one type of olfactory receptor protein
Olfactory receptor cells synapse in where
glomeruli in the olfactory bulb
Olfactory receptor cells synapse in glomeruli in the olfactory bulb, which contains what
neurons known as the mitral cells, which in turn send their axons into the brain
Each glomerulus processes information from just one type of olfactory receptor cell (expressing a particular type of olfactory receptor protein). Thus, each glomerulus processes what
a distinct odor
Humans have 339 different olfactory receptor proteins/cell types, but we can recognize up to ten thousand different odorants through what
combinatorial processing
Mitral cell axons project directly to the amygdala and to two regions of limbic cortex in the temporal lobe which are what
piriform cortex (which is considered to be primary olfactory cortex) and entorhinal cortex
Transduction of taste is similar to what
chemical transmission that takes place at synapses
When a tasted molecule binds with a receptor, it produces what
changes in membrane permeability that cause receptor potentials
Different substances bind with different types of receptors, producing different what (taste)
taste sensations
Taste buds consist of groups of twenty to fifty taste receptor cells, which all make what
one particular type of taste receptor protein
Taste receptor cells do not have traditional action potentials. They release glutamate how
in a graded fashion
Taste receptor cells are replaced about every how many days
ten days
Taste receptor cells are replaced about every ten days, why
because they are directly
exposed to a rather
hostile environment
what is GUSTATION
taste
Six different categories of taste receptors have been identified. These receptors detect: what
sourness (pH level) – also detects carbonation (bubbles) • sweetness (sugar) • saltiness (ions) • umami (glutamate) aka savoury • fat (certain proteins?) • bitterness (a variety of different molecules)
Umami is taste sensation produced by what
glutamate, which is an amino acid found in foods that are high in proteins (meat and cheese)
MSG (monosodium glutamate) activates what
both salt and umami receptors
Every bitter taste is unique. There is a different type of bitter receptor for what
every bitter-tasting molecule.
Sugar taste receptor cells are instinctively what
rewarding/reinforcing. Direct stimulation of them (or their downstream structures in the cerebral cortex) is inherently reinforcing
Bitter taste receptor cells are instinctively what
aversive. People often grow to appreciate some bitter taste cell activity (as an acquired taste).
