Sensory Neurons Flashcards
What are sensory receptors?
Specialized cells that transduce, or convert
sensory energy into neural activity
Receptors are energy ___________ and respond only to a ___________ band of energy
Receptors are energy filters and respond only to a narrow band of energy
Describe the transduction of energy related to Audition.
Air pressure waves converted into mechanical energy, activates the
auditory receptor cells to produce AP
Describe the transduction of energy related to Vision.
Light converted to chemical energy
in photoreceptors, and this is converted
into action potentials
Describe the transduction of energy related to Somatosensory system.
Mechanical energy activates
mechanoreceptors which produce action
potentials
What are receptive fields?
Specific part of the world to which a
sensory receptor responds to
True or False: Communication between Neurons is CHEMICAL process not electrical
TRUE!
What is the link between Receptor Density and Sensitivity?
Higher density of sensory receptors leads
to increased sensitivity (e.g.; Two-Point sensitivity and pitch discrimination)
Where are photoreceptors located?
in the retina
What are the two types of photoreceptors?
Rods and Cones
What are Photoreceptors?
Receptor cells of vision
Where are rods located?
Pheripheral Retina
What are rods sensitive to?
Sensitive to dim light, night vision
Where are cones located?
Densely packed in the fovea
What are cones photoreceptors sensitive to?
Sensitive to bright light, day vision and color vision
What occurs when we see an object?
Light rays pass through cornea, bended by the lens focused in retina and then transduced by photoceptors, bipolar neurons synapse with the retinal ganglion cells
What is refraction in the visual process?
bending of light rays passing through cornea and lens bend (refract) light rays to focus them on the retina.
What kind of vision defect can you suffer from a stroke?
Visual Field Defect
How can visual field defect affect communication? (3)
- Reading
- Communication
- identification of gestures
What are the two main visual pathways?
Geniculostriate Pathway
Tectopulvinar Pathway
Optic nerves leave each eye and cross at the_________
Optic nerves leave each eye and cross at the optic chiasm
What portion of fibers from each eye cross at the optic chiasm?
But only half of fibers (nasal ½) from each eye cross
What is the consequence of the the crossing at the optic chiasm in visual field perception?
The right half of each eye’s visual field is transmitted to the left hemisphere while the left half of each eye’s visual field is transmitted to the right hemisphere
What is the order of the visual input transmission? (6)
Eye
Optic nerve
Optic Tract
LGN
Optic radiations
Primary Visual Cortex
The optic tract relays the information afterwards to ?
LGN of the Thalamus
The LGN projects visual information to?
The primary visual cortex in the occipital lobes
What is another name for the primary visual cortex in the occipital lobes?
Striate cortex
What map type of does the primary visual cortex contains?
Retinotopic
What is another common name for the Geniculostriate Pathway? What does it mean?
The WHAT pathways, means it help us distinguish what things are.
What is another common name for the Tectopulvinar Pathway? What does it mean?
The WHERE pathways, means it help us distinguish where things are.
Detects stimuli in space and helps orient us to stimuli
What is the retinotopic map of the visual field? (2)
mapping of visual input from the retina to neurons
Map is upside down & inverted & reversed
What does the Geniculostriate pathway takes part of? (2)
Pattern recognition
Conscious visual functions
The right visual field projects to the ______________ cortex
left visual cortex
The central visual field projects to the ______________ cortex
Peripheral visual cortex
The peripheral visual field projects to the ______________ cortex
medial cortex
The Upper visual field projects onto the ________________ cortex.
lower visual cortex
The lower visual field projects onto the ________________ cortex.
upper visual cortex
Describe Anopsia? (3)
Visual field deficits
Primary Sensory Disorder
Most Common after stroke
What visual deficit can result from damage in the occipital lobe or optic radiations?
Anopsia
In the tectopulvinar pathway, the optic nerve leaves the eye and projects to which colliculus?
Superior Colliculus
In the tectopulvinar pathway, pathway extends from superior colliculus to_______________ of the ___________
Pathway extends from superior colliculus to lateral posterior-pulvinar complex of the thalamus
In the tectopulvinar pathway, pathway extends from thalamus to other ______________ in __________and __________ lobes
Pathway extends from thalamus to other visual areas in temporal and parietal lobes
Clinical Example: A.S is cortically blind but is able make judgement about spatial location. A.S’s condition is called:
Blindsight
What is the cause of blindsight in the visual pathways?
Geniculostriate path is damaged but tectopulvinar path is spared
What do the auditory receptors detect? (3)
Detect the frequency, amplitude, and complexity of air-pressure waves
What is frequency ?
Rate at which waves vibrate in Hz
What is the name of our perception of Frequency?
Pitch
Low frequency sounds are typically associated to __________________ sounds and high frequency sounds are _________________ sounds
Low frequency sounds are typically associated to low-pitched sounds and high frequency sounds are high-pitched sounds
What is amplitude in relation to sounds?
The intensity of a sound and normally measured in dB
What is the name of our perception of intensity?
Loudness
Low amplitude sounds are typically associated to ____________sounds and high amplitude sounds are _________________ sounds
Low amplitude sounds are typically associated to loud sounds and high amplitude sounds are soft sounds
What is complexity related to sounds?
The mixture of frequencies in a sound.
What is timbre? (2)
Complexity of a sound
Mixture determines the sound’s timbre or perceived uniqueness
(Provides information about the nature of a sound e.x trombone vs. violin playin the same damn note)
What are the three anatomical divisions of the human ear?
OE, ME, IE
What constitute the OE?(2)
Pinna and external ear canal
What constitute the ME? (2)
Eardrum and ossicles
What constitute the Inner Ear? (3)
Oval window, cochlea, semicircular canals
___________ waves are _______ and transformed in the ear.
Sound pressure waves are amplified and transformed in the ear
Where is the frequency of a sound transduced in the IE?
BM
What are the characteristics of the BM? (2)
Thick at the base, tuned for high frequencies
Thin and wide at the apex, tuned for low frequencies
What happens when the membranes are bent in the IE?
generate action potentials in hair cells (axons form CN 8)
What is tonotopic theory in the BM?
Different points on the basilar membrane and in the cortex represent different sound frequencies
What is the path of the auditory stimulus from the cochlea of the left ear to the Cerebral cortex?
2 hemispheres
4 levels
7 (x2 both sides) nuclei structures
VCN DCN OC TB IC MGN A1 A2
The auditory nerve projects to which structure in the hindbrain? (3) CN OC TB
Cochlear Nuclei Olivary Complex Trapezoid body
In the auditory pathway, the axons from the hindbrain project to the __________ aka ___________
Axons from hindbrain project to inferior colliculus (i.e., lateral lemniscus).
In the auditory pathway SOME axons terminate at the ___________________ important for sound ____________ and tracking.
Some axons terminate at inferior colliculus. Important for sound localization & tracking.
In the auditory pathway: Axons from inferior colliculus project to ___________________
medial geniculate nucleus of the thalamus
In the auditory pathway: Axons from thalamus project to_____________________________________
primary auditory cortex (Heschl’s gyrus in temporal lobe) & secondary auditory cortex
In the auditory pathway, Pathways cross in ______________ &_____________, and then recross in thalamus
Pathways cross in hindbrain & midbrain, and then recross in thalamus
In the End: Information from each ear reaches ________________________________________
End result: information from each ear reaches both hemispheres
Where are the vestibular organs located and what are their roles?
In the IE, balance & perception
What bend and move when head moves in the vestibular system?
Hair cells
What consists the vestibular system? (2)
3 Semicircular canals
Otolith organs (utricle, saccule)
