test 1 Flashcards
What is the difference between sensation and perception
Sensation is external
perception is internal
What is sensation
The process by which our senses receive information from the outside environment and encode that information into sensory neural impulses
What is perception
process by which the brain processes, organizes,
selects, integrates, and interprets neural signals generated by sensory
organs.
3 components of a sensory system
The sensory organ
neural pathways that transport info to the brain
brain regions that process sensory info and generate perceptions and behavior
3 things a sensory system can provide information from
the ouside world
the inside of the body
from memory and imagination
Psychophysics
Relationship between the physical stimulus and the resulting sensation
Psychometric function
A function that shows the relationship between a stimulus and the perceived stimulus
Intensity
strength of a stimulus
spatial properties of a stimulus
where the stimulus originates, directionality, movement, and vibration
Temporal properties of a stimulus
order of events, temporal separation between events, duration and frequency
detection threshold
minimum amount of stimulus to ellicit a response
perception threshold
the threshold required for a sensory input to be perceived.
Subliminal signals
signals that are detected but are not perceived ie. the clothes on your skin
or toungue in your mouth.
Range franctionation
different cells have
different thresholds for firing, over a
range of stimulus intensities
look at image
Adaptation
prior exposire to a condition can heighten or dampen activity of a sensory system
happens when you are continuosly exposed to a stimulus
specific to each system
habituation
prior exposure to a condition can heighten or dampen activity of a sensory system
specific to the brain
KNow the different sensory facial nerves and their functions
flow of information from sensory neurons to the brain
Afferent neurons, Dorsal root ganglions, to the spinal chord to the brain
Dermatomes
The territory innervated by each spinal nerve arising from each dorsal root ganglion
ex. shingles only affects a single dermatome
Ia, Ib, II afferent neurons
Large and fast nerve fibers, used to supply sensory receptors to muscles for proprioception
Ab afferent fibers
smaller than Ia an Ib
convery touch information
ADelta afferent fibers
small and slow nerves
convery pain and temp info
C afferent fibers
small and slow nerves
convery pain and temp info
Receptive field
An area of the skin innervated with only one nerve ending/axon
The closer touch is to the axon the higher the signal, If touch is farther from the center of the receptive field the signal is lower
How do receptive fields work together
Overlapping receptive fields across the body can signal to the brain where touch is.
Where are smaller receptive fields found and where are larger receptive fields found
Sensitive areas such as the fingers and mouth have a smaller receptive fields as they are areas that require a higher sensitivity to touch.
Slowly adapting afferents
Generates a sustained signal
Rapidly adapting afferents
generate a short burst of signals
somatic sensory afferents
generates receptor potentials from a stimulus.
A sum of receptor potentials will cause depolarization and and action potential
Mechanically gated ion channels
a mechanical force opens an ion channel causing depolarization
ex. Piezo-1 receptor which opens when a downward force is applied. Does not open when there is a lateral force.
Merkle cell receptors
find the form and texture
are used to obtain information about edges, points, corners and curvature.
They are small receptors and they have the highest spatial resoltion of all sensory afferents
What atre merkel cell complexes made from
Merkle cell proper and the merkel disc.
How does touch activate merkel cells
pressure opens Piezo 2 receptors, this opens Na/K channels which depolarize the cell. This allows the influx of Ca2+, Ca2+ causes the release of norepinephrine.
25% of mechanorecption
Meisners corpuscles
have a small receptive field
Give you motion detection and grip control
give you the ability to detect skin motion
is 40% of mechanorection
lamellar cells found in the meissner corpuscles
Made with A-delta fibers, and C-fibers
Pacinian corpuscle
found deep in the skin
10-15% of mechanoreceptors
detect vibrations through held objects
Ruffini corpuscles
found deep in the skin
20% of mechanorecpetion in the skin
detects stretch
