Final Lecture: Review Flashcards
Prior stimulation to a receptor does what?
Decreases sensitivity
What is the first step in stimulus perception?
Conduction of the stimulus
What is the function of the middle ear?
The middle ear improves transmission to the cochlea
The auditory nerve projects where?
To the cochlear nucleus
The cochlear nucleus projects where?
To the inferior colliculus
The inferior colliculus projects where?
To the medial geniculate body of the thalamus
The medial geniculate body of the thalamus projects where?
To the primary auditory cortex
What do cones provide?
Color discrimination
Photoreceptors connect to which type of cell?
Bipolar, amacrine, and horizontal cells
Are nociceptors regarded as sensory receptors?
No
What is parallel processing?
Processing of the same modality of information in different areas of the brain
What is stream segregation?
Processing of different modalities in different areas of the brain
What controls input into the thalamus?
The reticular thalamic nucleus
Classical pathways are also referred to as what?
Lemniscal pathways
Non-classical pathways are referred to as what?
Extralemniscal pathways
Classical pathways use what part of the thalamus?
The ventral thalamus
Non-classical pathways use what part of the thalamus?
The dorsal medial thalamus
How many modalities do classical pathways process?
One
How many modalities do non-classical pathways process?
Multiple
What cells lie between photoreceptors and retinal ganglion cells?
Bipolar, amacrine, and horizontal cells
Retinal ganglion cells of the classical pathway project from the optic chiasm to what?
The lateral geniculate nucleus of the thalamus
Retinal ganglion cells of the non-classical pathway project from the optic chaism to what?
The Superior colliculus
The Pulvinar nucleus of the thalamus
Type 1 auditory nerve fibers innervate what?
Inner hair cells
Type 2 auditory nerve fibers innervate what?
Outer hair cells
Do type 1 auditory nerve fibers converge or branch and diverge on inner hair cells?
Converge
Do type 2 auditory nerve fibers converge or branch and diverge on outer hair cells?
Diverge
What is the maximum ratio of type 1 auditory nerve fibers to type 2 auditory nerve fibers?
95:5
What do cochlear implants stimulate?
The auditory nerve
What is the function of the basilar membrane?
To separate sounds based on their frequencies
Dermatomes are sections of skin innvervated by what?
Many fibers projecting from one dorsal root
What taste is built in and not learned?
Sweet
Pheromones activate cells where?
In the vermeronasal organ
Where do olfactory bulb projections primarily lead?
The central nucleus of the amygdala
Out of all of the senses, which sense is out of place in relation to the thalamus?
Olfaction (because it lacks a thalamic representation)
What is the primary function of the superior colliculus?
To provide visual reflexes
The frequency selectivity of the basilar membrane is dependent upon what?
The intensity of the sound
Where do magnocellular and parvocellular layers reside?
In the lateral geniculate nucleus of the thalamus
Where do taste fibers project?
To the nucleus of the solitary tract
What is the short way for sensory systems to reach the amygdala?
Through a direct projection from the dorsal medial thalamus
What is the long way for sensory systems to reach the amygdala?
Through the cortex from the primary and association cortices
What part of the amygdala do sensory systems project to?
Olfactory: Central nucleus of the amygdala
Others: Lateral nucleus of the amygdala
What does lateral inhibition do?
It increases contrast
How does lateral inhibition work?
By having excitatory and inhibitory impulses enter the same cells
Cells organized by frequency are known to be what?
Tonotopically organized
What is the hearing threshold?
The intensity at which a response is given 50% of the time
What is dark adaption?
The increase in sensitivity resulting from photoreceptors not being stimulated
How does dark adaption differ from adaption?
In adaption, stimulation decreases receptor sensitivity
In dark adaption, lack of stimulation increases receptor sensitivity
What is the function of outer hair cells?
To act as motors and amplify the movement of the basilar membrane
How much can outer hair cells increase the intensity of the a sound by?
50dB
What is the papilla?
The area where the optic nerve enters the retina
How does the papilla affect vision?
It creates a blindspot in our visual field
Why don’t we see a blindspot in our visual field?
Our brain fills in the gap
What is the basis of color vision?
Spectral sensitivity of trichromatic (R/G/B) cones
How is frequency discrimination achieved?
Through the basilar membrane interacting with a transduced sound wave and its time pattern
What happens to a cortical system if there is no input?
The idle system will be taken over by an active system (plasticity)
What is the sensitivity of a sense affected by?
The intensity and modality of the stimulation
Where does the ventral thalamus project?
To primary sensory cortices
Where does the dorsal medial thalamus project?
Secondary cortices
Association cortices
Sub-cortical structures
Where do C-fibers in the dorsal horn project?
Lamina II
Where do A𝛿-fibers in the dorsal horn project?
Lamina I
What is ultra-acoustic emission?
The generation of sound by the cochlea
How does ultra-acoustic emission work?
The basilar membrane self-oscillates, mechanical waves are sent backwards to the oval window, through the bones of the inner ear, and to the tympanic membrane which vibrates and generates sound in the ear canal.
