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Neurophysiology II > Exam Two > Flashcards

Exam Two Flashcards

1
Q

What is accommodation?

A

increasing lens strength from 20-34D.

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2
Q

Parasympathetic causes what in accommodation?

A

-contraction of ciliary muscle allowing relaxation of suspensory ligaments attached radially around lens, which becomes more convex, thus increasing refractive power.

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3
Q

What is presbyopia?

A
  • loss of elasticity of the lens with age

- this decreases accommodation.

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4
Q

Types of errors of refraction?

A
  • Emmetropia
  • Hyperopia
  • Myopia
  • astigmatism
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5
Q

What is emmetropia?

A
  • normal vision

- ciliary muscle is relaxed in distant vision

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6
Q

What is hyperopia?

A
  • “far-sighted”

- focal point is behind the retina.

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7
Q

What is myopia?

A
  • “near-sighted”

- focal point in front of retina.

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8
Q

What is astigmatism?

A

irregularly shaped

  • cornea(more common), or
  • lens(less common).
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9
Q

Information the Snellen Eye Chart gives you

A

ratio of what that person can see compared to a person with normal vision.

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10
Q

What is the fovea centralis?

A

area of greatest visual acuity.

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11
Q

Outside the fovea centralis, visual acuity increases or decreases by how much and where?

A

decreases by more than 10 fold near periphery.

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12
Q

What is Stereopsis?

A

binocular vision

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13
Q

What happens in stereopsis?

A
  • eyes are separated by 2 inches-slight difference in position of visual image on both retinas
  • closer objects are more laterally placed.
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14
Q

What is glaucoma?

A
  • increased intraocular pressure by compression of optic nerve
  • can lead to blindness.
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15
Q

What is the function of the retina and what does it contain?

A
  • Peripheral extension of CNS
  • Processing of visual signal.
  • Contains photoreceptors(rods, cones) and other cells(amacrine, ganglion, horizontal, bipolar)
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16
Q

Examples of photoreceptors?

A

Rods and cones

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17
Q

Light breaks down what?

A

Rhodopsin(rods) and cone pigments(cones)

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18
Q

When stimulated by light, photoreceptors release less of?

A

glutamate

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19
Q

What are bipolar cells?

A

cells that connect photoreceptors to either ganglion cells or amacrine cells.

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20
Q

Two types of bipolar cells?

A

-“ON” or invaginating bipolars-hyperpolarized by glutamate -“OFF” or flat bipolars-depolarized by glutamate.

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21
Q

What are ganglion cells?

A
  • can be “ON” or “OFF” bipolar

- generate action potentials carried by optic nerve.

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22
Q

Three types of ganglion cells

A
  • x(p)
  • y(m)
  • w cells
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23
Q

P(x) ganglion cells

A
  • most numerous(55%)
  • slower conduction velocity
  • small receptive field
  • responsible for color vision
  • project to Parvocellular layer of lateral geniculate nucleus.
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24
Q

M(y) ganglion cells

A
  • receive input from amacrine cells
  • 5% of ganglion cells
  • larger receptive field
  • fast conduction velocity
  • more sensitive to brightness
  • black and white images
  • project to magnocellular lateral geniculate nucleus.
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25
Q

W ganglion cells

A
  • smallest
  • slowest conduction velocity
  • 40% of all ganglion cells
  • act as light intensity detectors
  • broad receptive fields
  • receive most of input from rods
  • important for crude vision in dim light
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26
Q

Horizontal cells

A
  • non-spiking inhibitory interneurons
  • When depolarized, they inhibit photoreceptors.
  • they make complex synaptic connections with photoreceptors.
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27
Q

What are amacrine cells?

A

cells that receive input from bipolar cells and project to ganglion cells. They release different neurotransmitters such as GABA, dopamine.

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28
Q

Center-Surround fields

A

receptive fields of bipolar and ganglion cells.

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29
Q

What is a Center Field?

A

Field mediated by all photoreceptors, synapsing directly onto the bipolar cell.

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30
Q

What is a Surround Field?

A

Field mediated by photoreceptors which gain indirect access to bipolar cells via horizontal cells.

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31
Q

Photoreceptor contribution to fields

A

photoreceptors contributing to center field of one bipolar cell contributes to surround field of other bipolar cells.

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32
Q

Simultaneous stimulation of light of both fields gives what?

A

no net response of either field.

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33
Q

If center field is on, surround is?

A

off

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34
Q

In the Fovea, what is the ratio of cone:bipolar cell:ganglion cell?

A

(Can be as low as) 1 cone:1 bipolar cell: 1 ganglion cell

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35
Q

in peripheral retina, what’s the ratio of rods:bipolar cell: ganglion cell

A

hundreds of rods can supply a single bipolar cell and many bipolar cells connected to 1 ganglion cell.

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36
Q

In dark adaptation, what adapts first?

A

cones then rods but rods adapt to a greater extent.

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37
Q

what happens in dark adaptation?

A

dilation of pupil, neural adaption, cone adaptation increases less than 100 fold, rod adaption increases more than 100 fold, and increase of retinal sensitivity 10,000 fold

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38
Q

3 types of cones

A

blue, green, and red sensitive

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39
Q

What is color blindness?

A

sex-linked trait carried on x chromosomes. Transmitted by the female, but occurs exclusively in males.

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40
Q

Most common color blindness

A

red-green. missing either red or green cones.

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41
Q

Loss of red cones is called what?

A

Protanope-decrease in overall visual spectrum.

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42
Q

Loss of green cones is called what?

A

Deuteranope-normal overall visual spectrum.

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43
Q

Ishihara chart

A

helps to distinguish between green, yellow, orange, and red problems.

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44
Q

Loss of blue cones

A
  • rare
  • may be under-represented
  • “Blue Weakness”
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45
Q

List the visual pathway.

A
  • optic nerve to optic chiasm
  • optic chiasm to optic tract
  • optic tract to lateral geniculate
  • lateral geniculate to primary visual cortex (geniculocalcarine radiation)
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46
Q

Lesion at optic nerve?

A

blind in ipsilateral eye

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47
Q

Lesion at optic chiasm?

A

bitemporal hemianopia

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48
Q

Lesion in optic tract?

A

contralateral homonymous hemianopia

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49
Q

Additional visual pathways?

A

from optic tracts to:

  • suprachiasmatic nucleus (biologic clock function)
  • pretectal nuclei (reflex movement of eyes - focus on objects of importance)
  • superior colliculus (rapid directional movement of both eyes – orienting reactions)
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50
Q

Primary visual cortex

A

Brodman area 17 (VI) - two times neuronal density

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51
Q

BM 17 simple cells?

A
  • respond to bar of light/dark

- above and below layer IV

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52
Q

BM 17 complex cells?

A
  • motion dependent

- same orientation sensitivity as simple cells

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53
Q

BM 17 color blobs?

A
  • rich in cytochrome oxidase in center of each occular dominance band
  • starting point of cortical color processing
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54
Q

BM 17 vertical columns?

A
  • input into layer IV

- hypercolumn - functional unit, block through all cortical layers about 1mm squared

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55
Q

Visual association cortex

A

-visual signal is broken down and sent over parallel pathways

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56
Q

Visual analysis

A
  • process along many paths in parallel

- at least 30 cortical areas processing vision

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57
Q

Parvo-interblob

A

high resolution static form perception (black and white)

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58
Q

Blob

A
  • color (V4)

- Achromatopsia

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59
Q

Magno-interblob

A
  • movement (MT)

- Stereoscopic Depth

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60
Q

Old visual system

A
  • old pathway projects to the superior colliculus
  • locating objects in visual field, so you can orient to it (rotate head and eyes)
  • subconscious
  • blindsight
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61
Q

New visual system

A
  • new pathway projects to the cortex

- consciously recognizing objects

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62
Q

Blindsight

A
  • patients who are effectively blind because of brain damage can carry out tasks which appear to be impossible unless they can see the object
  • ie. reach out and grasp objects, post a letter through a narrow slot
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63
Q

Why can effectively blind people carry out tasks which appear to be impossible unless they can see the object?

A
  • visual information travels along two pathways in the brain
  • if the cortical pathway is damaged, a patient may lose the ability to consciously see an object but still be aware of its location and orientation via projections to the superior colliculus at a subconscious level
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64
Q

Cortical fixation areas - Voluntary fixation mechanism (anterior)

A
  • person moves eyes voluntarily to fix on an object

- controlled by cortical field bilaterally in premotor cortex

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65
Q

Cortical fixation areas - involuntary fixation mechanism (posterior)

A
  • holds eyes firmly on object once it has been located
  • controlled by secondary visual areas in occipital cortex located just in front of primary visual cortex
  • works in conjunction with the superior colliculus (involuntary fixation is mostly lost when superior colliculus is destroyed)
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66
Q

Parasympathetic control of pupillary diameter?

A

causes decrease size of pupil - MIOSIS

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67
Q

Sympathetic control of pupillary diameter?

A

causes increase in size of pupil - MYDRIASIS

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68
Q

Pupillary light reflex pathway:

A
  • optic nerve to
  • pretectal nuclei to
  • Edinger Westphal to
  • ciliary ganglion to
  • pupillary sphincter to
  • cause constriction (parasympathetic)
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69
Q

What is Horner’s Syndrome?

A
  • interruption of SNS supply to an eye

- from cervical sympathetic chain

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70
Q

What are symptoms of Horner’s syndrome?

A
  • constricted pupil compared to unaffected eye
  • drooping of eyelid normally held open in part by SNS innervated by smooth muscle
  • dilated blood vessels
  • lack of sweating on that side of face
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71
Q

What are the functions of the medial and lateral recti (extraoccular muscles)?

A

-medial rectus of one eye works with the lateral rectus of the other eye as a yoked pair to produce lateral eye movements

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72
Q

What are the functions of the superior and inferior recti (extraoccular muscles)?

A
  • elevate and depress the eye respectively

- most effective when the eye is abducted

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73
Q

What is the function of the superior oblique muscles?

A

-lowers the eye when it is adducted

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74
Q

What is the function of the inferior oblique muscles?

A

-elevates the eye when it is adducted

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75
Q

What is the innervation of the extraoccular muscles?

A
  • CN III: rest of the muscles
  • CN IV: superior oblique only
  • CN VI: lateral rectus only
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76
Q

Summary of extraoccular muscles

A

See page 7 of notes for chart

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77
Q

What is the unit of sound?

A

decibel (dB)

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78
Q

Decibel = ?

A

1/10 log [ 1 (measured sound)/1 (standard sound) ]

79
Q

What is the reference pressure for standard sound?

A

0.02 x 10^-2 dynes/cm squared

80
Q

Sound

A

-energy is proportional to the square of pressure

81
Q

A 10 fold increase in sound energy equals?

A

1 bel

82
Q

One dB represents an actual increase in sound energy of?

A

about 1.26 X

83
Q

Ears can barely detect a change of how many decibels?

A

1 dB

84
Q

How many decibels is a whisper?

A

20 dB

85
Q

How many decibels is a normal conversation?

A

60 dB

86
Q

How many decibels is a symphony?

A

100 dB

87
Q

How many decibels is a threshold of discomfort?

A

130 dB

88
Q

How many decibels is a threshold of pain?

A

160 dB

89
Q

What is the frequency of audible sound in a young adult?

A

20-20 000 Hz

-decreases with age

90
Q

What is the greatest acuity for the frequency of an audible sound?

A

1000-4000 Hz

91
Q

In tympanic membrane and ossicles, what is impedance matching?

A

it occurs between sound waves in air and sound vibrations generated in the cochlear fluid

92
Q

What percentage is perfect for sound frequency of 300-3000 Hz?

A

50-75%

93
Q

Ossicular system

A
  • reduces amplitude by 1/4
  • increases pressure against oval window 22 X (increased force 1.3, decreased area from TM to oval window 17)
  • non functional ossicles or ossicles absent
  • decrease in loudness about 15-20 dB
  • medium voice now sounds like a whisper
94
Q

Ossicular system: Attentuation of sound by contraction of?

A
  • Stapedius muscle - pulls stapes outward

- Tensor tympani - pull malleous inward

95
Q

What causes contraction of stapedius and tensor tympani muscles?

A

CNS reflex

96
Q

What is the attenuation of sound activated by?

A
  • loud sound

- speech

97
Q

What is the latency period of the attenuation of sound?

A

40-80 msec

98
Q

The attenuation of sound is most effective at frequencies of?

A

< 1000 Hz

99
Q

Attenuation of sound:

A

creation of rigid ossicular system which reduces ossicular conduction

100
Q

What is the function of attenuation of sound?

A
  • protect cochlea from very loud noises

- makes low frequency sounds in loud environments

101
Q

The cochlea is a system of 3 coiled tubes which are:

A
  • scala vestibuli
  • scala media
  • scala tympani
102
Q

Scale Vestibuli

A
  • separated from the scala media by Reissner’s membrane
  • associated with the oval window
  • filled with perilymph (similar to CSF)
103
Q

Scala Media

A
  • separated from scala tympani by basilar membrane
  • filled with endolymph secreted by stria vascularis which actively transports K+
  • top of hair cells bathed by endolymph
104
Q

Scala Tympani

A
  • associated with the round window

- filled with perilyph which bathes lower bodies of hair cells

105
Q

What is Endocochlear potential?

A

-electrical potential of +80mV exists between endolymph and perilymph due to active transport of K+ into endolymph

106
Q

What is the purpose of the endocochlear potential?

A
  • sensitizes hair cells

- inside of hair cells (-70mv vs -150mv)

107
Q

What is the function of cochlea?

A
  • change mechanical vibrations in fluid into action potentials in CN 8
  • causes movement of the basilar membrane
  • increased displacement - increased neuronal firing resulting in an increase in sound intensity (some hair cells only activated at high intensity)
108
Q

What causes movement of the basilar membrane?

A

sound vibrations created in the fluid of cochlea

109
Q

What is the Place Principle?

A
  • different sound frequencies displace different areas of the basilar membrane
  • natural resonant frequency
110
Q

Hair cells near oval window (base):

A
  • short and thick

- respond best to higher frequencies (>4500Hz)

111
Q

Hair cells near helicotrema (apex):

A
  • long and slender

- respond best to lower frequencies (<200Hz)

112
Q

What is the Fourier analysis by the cochlea

A

any complex wave can be broken down into its component sine waves with differing phases, frequencies and amplitudes

113
Q

The cochlea behaves like a Fourier analyser by:

A
  • acts as a kind of auditory prism

- sorting out vibrations of different frequencies into different positions along the membrane

114
Q

Central Auditory Pathway

A
  • organ of corti to ventral and dorsal cochlear nuclei in upper medulla
  • cochlear nucleus to superior olivary nucleus (most fibers pass contralateral, some stay ipsilateral)
  • superior olivary nucleus to nucleus of lateral lemniscus
  • nucleus of lateral lemniscus to inferior colliculus (via lateral lemniscus)
  • inferior colliculus to medial geniculate nucleus
  • medial geniculate nucleus to primary auditory cortex
115
Q

Where is the primary auditory cortex located?

A

in the superior gyrus of temporal lobe

116
Q

What does the primary auditory cortex do?

A

tonotopic organization

  • high frequency sounds: posterior
  • low frequency sounds: anterior
117
Q

What is S.Q.U.I.D?

A

Super Quantum Interference Device

-detects changes in central sensitivities in the primary auditory cortex

118
Q

What does the air conduction pathway involve?

A
  • external ear canal
  • middle ear
  • inner ear
119
Q

What does the bone conduction pathway involve?

A

direct stimulation of cochlea through the vibration of the skull as the cochlea is imbedded in the petrous portion of the temporal bone

120
Q

Reduced hearing may involve?

A
  • ossicles (air conduction)

- cochlea or associated neural pathway (sensory neural loss)

121
Q

If there is a known bad ear, how can we differentiate a hearing loss?

A
  • Weber test (512 Hz) - tuning fork placed on midline of the skull
  • if sounds louder in bad ear: conduction loss in bad ear (external canal or ossicles involved)
  • if sounds louder in good ear: sensory neural loss in bad ear
122
Q

What test confirms the results of the Weber test?

A

Rinne test

  • air conduction > bone: sensory neural
  • bone conduction > air: air conduction loss
123
Q

What two principal mechanisms determine the horizontal direction from which sound originates from?

A
  1. Time lag between ears
    - functions best at frequencies <3000 Hz
    - involves medial superior olivary nucleus (neurons that are time lag specific)
  2. Difference in intensities of sounds in both ears
    - involves lateral superior olivary nucleus
124
Q

Exteroceptive chemosenses?

A
  • taste

- olfaction (smell)

125
Q

Taste works together with?

A

smell

126
Q

What are the 6 categories of primary tastes?

A
  • sweet
  • salt
  • sour
  • bitter (lowest threshold - protective mechanism)
  • Umami (savory/pungent)
  • Fatty (some evidence supports this as a 6th taste)
127
Q

Olfaction (smell)

A

primary odors (100-1000 different receptors)

128
Q

Taste receptors:

A
  • may have preference for stimuli

- influenced by past history

129
Q

How are taste receptors influenced by past history?

A
  • recent past: adaptation

- long standing: memory and conditioning-association

130
Q

Sour taste

A

caused by acids (H ion concentration)

131
Q

Salty taste

A

caused by ionized salts (primarily Na+)

132
Q

Sweet taste

A
  • most are organic chemicals (ie. sugars, esters, glycols, alcohols, aldehydes, ketones, amides, amino acids)
  • inorganic salts of lead (Pb) and beryllium (Be)
133
Q

Bitter taste

A

no one class of compounds but:

  • long chain organic compounds with N
  • alkaloids (quinine, strychnine, caffeine, nicotine)
134
Q

Umami/Savory taste

A
  • flavor associated with MSG

- receptor responds to amino acids

135
Q

Taste sensations are generated by?

A
  • complex transactions among chemicals and receptors in taste buds
  • subsequent activities occurring along the taste pathways
136
Q

What contributes to gustatory experiences?

A
  • sensory processing
  • centrifugal control
  • convergence
  • global integration among related systems
137
Q

What consists of taste buds distributed over the tongue, pharynx and larynx?

A

taste neuroepithelium

138
Q

Taste buds are aggregated in relation to 3 kinds of papillae which are?

A
  1. fungiform: blunt pegs 1-5 buds/top
  2. foliate: submerged pegs in serous fluid with 1000’s of taste buds on side
  3. circumvallate: stout central stalks in serous filled moats with tastes buds on sides in fluid
139
Q

What are taste buds?

A

40-50 modified epithelial cells group in barrel shaped aggregate beneath a small pore which opens onto epithelial surface

140
Q

Innervation of taste buds:

A
  • each taste nerve arborizes and innervates several buds (convergence in 1st order)
  • receptor cells activate nerve endings which synapse to base of receptor cell
  • individual cells in each bud differentiate, function and degenerate on a weekly basis
141
Q

Taste nerves:

A
  • continually remodel synapses on newly generated receptor cells
  • provides trophic influences essential for regeneration of receptors and buds
142
Q

Adaptation of taste:

A
  • rapid: within minutes
  • taste buds account for 1/2 of adaptation
  • rest of adaptation occurs higher in CNS
143
Q

What is the CNS pathway of taste for the anterior 2/3 of the tongue?

A
  • lingual nerve to
  • chorda tympani to
  • facial nerve (CN VII)
144
Q

What is the CNS pathway of taste for the posterior 1/3 of the tongue?

A

-CN IX (petrosal ganglion)

145
Q

What is the CNS pathway of taste for the base of the tongue and palate?

A

-CN X

146
Q

Where do the 3 CNS pathways of taste all terminate?

A

-nucleus tractus solitarius (NTS)

147
Q

What happens from the nucleus tractus solitarius?

A
  • goes to the VPM of thalamus via central tegmental tract (ipsilateral) which is just behind the medial lemniscus)
  • goes from the thalamus to the lower tip of the post-central gyrus in parietal cortext and adjacent opercular insular area in sylvian fissure
148
Q

What are the two taste receptors?

A
  • G protein linked receptors

- Ion channels

149
Q

What tastes are the G protein linked receptors responsible for?

A
  • bitter
  • sweet
  • umami
150
Q

What tastes are the ion channels responsible for?

A
  • sour

- salty

151
Q

Olfaction is the least understood because:

A
  • smell is subjective
  • hard to study in animals
  • rudimentary in humans (humans are microsmatic - poorly developed sense of smell)
152
Q

How many conchae does the nose have?

A

3 conchae bilaterally

153
Q

What are the conchae?

A

highly vascularized organs covered with erectile tissue

154
Q

What are the functions of the conchae?

A
  • moisten and warm incoming air

- limit loss of heat and water in expired air

155
Q

What happens to the conchae when you have a cold?

A
  • becomes engorged with blood
  • blocks air from reaching olfactory receptors
  • partial loss of smell
156
Q

What is found at the top of the conchae?

A

olfactory cleft made of olfactory epithelium

157
Q

What is the olfactory cleft/epithelium associated with?

A

olfactory receptors

158
Q

How much air reaches the olfactory cleft?

A
  • normally only a small portion

- sniffing increases the percentage by creating turbulence around the conchae

159
Q

What is another name for the vomeronasal organ?

A

Jacobson’s organ

160
Q

Where is the vomeronasal/Jacobson’s organ located?

A

medially on septum in lower part of nasal cavity

161
Q

What is the function of the vomeronasal/Jacobson’s organ?

A

appears to contribute to olfaction

-probably more receptive than olfactory epithelium to pheromones which have profound effects on behavior

162
Q

Where is the olfactory membrane located?

A

superior part of nostril

163
Q

What are olfactory cells?

A
  • bipolar nerve cells
  • 100 million in olfactory epithelium
  • 6-12 olfactory hairs/cells project in mucus
  • react to odors and stimulate cells
  • connect to olfactory bulb via cribriform plate
164
Q

What are the 3 cells in the olfactory membrane?

A
  • olfactory cells
  • cells which make up Bowman’s glands (secrete mucus)
  • Sustenacular cells (supporting cells)
165
Q

What are the characteristics of odorants?

A
  • volatile
  • slightly water soluble (for mucus)
  • slightly lipid soluble (for membrane of cilia)
166
Q

What is the threshold for smell?

A

-very low

167
Q

Methyl mercaptan:

A
  • 1/25 billion of mg/ml of air can be detected

- mixed with natural gas so gas leaks can be detected

168
Q

Stimulation of olfactory cells:

A
  • odorant binds to receptor protein
  • inside of protein is couple to a G-protein (3 subunits)
  • G-protein activates adenyl cyclase
  • adenyl cyclase converts ATP to cAMP which causes protein gated Na+ channels to open
  • Ca++ enters as well which opens chloride channels
  • high Cl- concentration inside olfactory receptors (ununsual)
  • efflux of Cl- prolongs depolarization
  • at every step the effect is amplified
169
Q

Is there such thing as a primary odor?

A

no

  • there is no objective, physical way of classifying smells systematically like color or tone
  • no classification enables one to predict the result of making mixtures (like color triangle)
170
Q

Primary sensations of smell:

A

-significant aspect of the brain’s analysis of odor is carried out by receptors in the olfactory membrane

171
Q

What is anosmia?

A
  • odor blindness
  • has been described for more than 60 different substances
  • may involve lack of a specific receptor protein
172
Q

What is the resting membrane potential for an olfactory receptor when not activated?

A
  • 55mv

- 1 impulse/20 sec to 2-3 impulses/sec

173
Q

What is the activated membrane potential for an olfactory receptor?

A
  • 30mv

- 20 impulses/sec

174
Q

Prolongation of response in response to positive charge:

A
  • Na+ and Ca++ influx during depolarization
  • Ca++ influx binds to and opens Cl- channel protein
  • high Cl- therefore have Cl- efflux therefore prolong depolarization
175
Q

How many glomeruli in an olfactory bulb?

A

several thousand per bulb

176
Q

What are glomerulus in olfactory bulb?

A

-connections between olfactory cells and cells of the olfactory tract

177
Q

What are the functions of the glomerulus in olfactory bulb?

A
  • receive axons from olfactory cells (25, 000)

- receive dendrites from large mitral cells (25) and smaller tufted cells (6)

178
Q

What are the four cells in the olfactory bulb?

A

-mitral cells
-tufted cells
granule cells
-periglomerular cells

179
Q

What do the mitral cells do?

A
  • continually active

- send axons into CNS via olfactory tract

180
Q

What do the tufted cells do?

A
  • continually active

- send axons into CNS via olfactory tract

181
Q

What do granule cells do?

A
  • inhibitory cell which can decrease neural traffic in olfactory tracts
  • receive input from centrifugal nerve fibers
182
Q

What do periglomerular cells do?

A

-inhibitory cells between glomerulus

183
Q

What does the very old CNS pathway for olfaction do?

A
  • medial olfactory area
  • feeds into hypothalamus and primitive areas of the limbic system (from medial pathway)
  • basic olfactory reflexes
184
Q

What does the less old CNS pathway for olfaction do?

A
  • lateral olfactory area
  • prepyriform and pyriform cortex - only sensory pathway to cortex that doesn’t relay via thalamus (from lateral pathway)
  • learned control/adversion
185
Q

What does the newer CNS pathway for olfaction do?

A
  • passes through the thalamus to orbitofrontal cortex (from lateral pathway)
  • conscious analysis of odor
186
Q

What forms the medial and lateral pathways?

A

-2nd order neurons form the olfactory tract and project to primary olfactory paleocortical areas

187
Q

What are the four primary olfactory paleocortical areas?

A
  • anterior olfactory nucleus
  • amygdala and olfactory tubercle
  • pyriform and periamygdaloid cortex
  • rostral entorhinal cortex
188
Q

What does the anterior olfactory nucleus do?

A

modulates information processiong in the olfactory bulbs

189
Q

What do the amygdala and olfactory tubercle do?

A

important in emotional, endocrine and visceral responses of odors

190
Q

What do the pyriform and periamygdaloid cortex do?

A

olfactory perception

191
Q

What does the rostral entorhinal cortex do?

A

olfactory memories

192
Q

Psychological links between olfactory of limbic function:

A
  • in humans odors can evoke recollection of past experience
  • not just the experience but also the mood or emotion that was felt at the time
  • sometimes very intensely which is seldom duplicated by either auditory or visual stimulation memory recall
193
Q

What is the psychological link between olfactory and limbic function thought to be due to?

A

direct penetration of the emotional areas of the limbic system by olfactory fibers

Neurophysiology II (2 decks)

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