Chapter 5- Sensory + Perceptual Contributions Flashcards
sensation
the physical stimulus with its physical properties, registered by specialized sensory organs -> organs decode sensory information, transforming them into neural impulses + sending them to the brain
perception
sensory/afferent information is mainly how the brain interprets a sensation -> translates the sensation into something meaningful
what information does motor control rely on to regulate movements
sensory (afferent)
**
closed-loop control systems
system goal ->
(input) ->
reference mechanism ->
(error) ->
executive level ->
(instructions) ->
effector level ->
(output) ->
environment ->
feedback
**
describe first part of closed-loop control systems
we have a goal- system input tells us what I want to do/which choice I am going to make
**
which stages of closed-loop control systems are within the SAME STAGE of PRE-ACTUAL movement (i.e. INFORMATION PROCESSING; just processing the information that was inputted)
-reference mechanism
-executive level
**
effector level of closed-loop control systems
after I get that information, I am able to send signals to the muscles to exert a force
**
environment stage of closed-loop control systems
if I am trying to squeeze + pop a balloon, environment will tell you to exert more force if balloon is still intact
other description of closed-loop control systems
after we identify the stimulus, the system (our body) is going to receive + process that information to program instructions ->
instruction goes to the muscles/effectors ->
I am then going to try to reduce the errors I make in the response programming stage; information from muscles, joints, tendons, eyes, ears, etc. will all feed back into trying to minimize errors
**
3 sources of sensory information/receptors
-exteroceptors
-proprioceptors
-interoceptors
**
exteroceptors
provide information about movement of objects in environment; events outside the body
**
propprioceptors
provide information about our own movements; events within one’s own body
**
interoceptors
provide information about the states of internal organs; pain
what information does vision provide
information about movements of objects in the environment + movement of one’s body in the environment
**
2 types of visual streams
-ventral
-dorsal
**
ventral stream
information that is central to the identification + recognition of objects is vital
-ex: looking for + recognizing a hammer
-specialized to identify objects + conscious perception of environment
-sensitive to what a person is looking at/focusing on
-requires contract, focus, sufficient light
-sends information to inferotemporal cortex -> provides cognitive information about objects in the environment
**
where does ventral stream send information to
interotemporal cortex
-provides cognitive information about objects in the environment
**
dorsal stream
attuned to information about how we control our motor system to interact with an object
-ex: picking up a hammer
-visual input is full field; doesn’t require focus
-seems to operate even in low light
-sends information to posterior parietal cortex -> provides information for the visual control of movement/action
**
where does dorsal stream send information to
posterior parietal cortex
-provides information for visual control of movement/action
**
optic ataxia brain injury
patient is able to recognize object but unable to use same visual information to guide hand accurately to object
-patients can use ventral stream but not dorsal stream
**
which stream does optic ataxia brain injury affect
dorsal
-patient can only use ventral stream
**
visual agnosia disorder
patient is unable to recognize common objects but could use visual information to grasp objects accurately
-patients can use dorsal stream but not ventral stream
**
which stream is affected in visual agnosia disorder
ventral stream
-patients can still use dorsal stream
Muller-Lyer illusion
the line connecting the 2 inward-pointing arrows appears to be longer than the line connecting the 2 outward-pointing arrows though the 2 lines are the same length
-environment (lines on outisde) affect how the lines inside are perceived
-MULLER ARROW
Ponzo illusion
the horizontal line closer to the apex of the slanted lines appears longer than the line farther from the apex, even though the 2 lines are the same length
-the environment (lines on outside) affect how the lines on the inside are percieved
-PONZO PYRAMID
horizontal-vertical illusion
the vertical line appears longer than the horizontal line, even though the 2 lines are the same length
-THINK LITERALLY A HORIZONTAL + VERTICAL LINE
Ebbinghaus-Titchener illusion
the circle in the middle appears larger when surrounded by smaller circles than when surrounded by larger circles, even though the middle circles in both figures are the same size
-THIS IS THE ONE WITH THE CIRCLES
____ creates perception bias
environment
what is applied to our head when our body moves
acceleration
what tells us how our body is oriented in space in terms of vertical alignment/standing upright
we have receptors in our ears -> vestibular system
**
vestibular system
sensory system responsible for providing our brain with information about our motion, head position, + spatial orientation
-also involved with motor functions that allow us to keep our balance, stabilize our head/body during movement, + maintain posture
where are the main components of vestibular system found
inner ear
-vestibular labrynth
what is vestibular labyrinth continuous with
cochlea
what is contained within vestibular labyrinth
semicircular canals
semicircular canals
3 tubes each situated in a plane in which the head can rotate
-each canal can detect 1 of the following head movements- nodding up/down, shaking side to side, tilting left/right
what are semicircular canals filled with
a fluid called endolymph
describe movement of endolymph
when head is rotated it causes movement of endolymph through the canal corresponding to that plane of movement
where does endolymph flow to
an expansion of the canal called AMPULLA, which has hair cells that serve as sensory receptors of vestibualr system
ampulla
has hair cells that serve as sensory receptors of vestibular system
stereocilia
a collection of small hairs at top of each hair cell
what causes movement of stereocilia
movement of endolymph
what occurs from movement of stereocilia
release of neurotransmitters that send information about the plane of movement to the brain
what type of organs are in the vestibular system
otolith organs
otolith organs
detect forward/backward movements + gravitational forces
2 otolith organs in vestibular labyrinth
-utricle
-saccule
utricle
detects movement in horizontal plane
saccule
detects movement in vertical plane
otoconia
crystals of calcium carbonate
describe how hair cells detect movement
within utricle + saccule, hair cells detect movement when otoconia (crystals of calcium carbonate) shift in response, leading to movement in layers below the otoconia + displacement of hair cells
The Moving Room
-3-sided room with walls that could be moved without moving the floor; even with no mechanical effect of the wall, there was loss of balance
-the moving walls changed optical flow (the patterns we are used to)
-moving wall forward made subject feel like they were falling forward, so they compensated by falling backwards even though the wall physically had nothing to do with them
who conducted The Moving Room
Lee + Aronson
closing eyes makes balance easier or harder
harder
-removes visual feedback
focusing on an object makes balance easier or harder
easier
**
what influences the role of vision during walking/running
optical flow
-ex: using a split-belt treadmill, optical flow can enhance learning rate during adaptation
what information does vision provide
information about how to accommodate action, + is influenced by how fragile an object appears to be
-ex: you lift your leg more to maximize clearance of an object
-bigger object = lift leg higher
-react more to something fragile like a wine glass than you would to a block of wood
action-specific perception
relative body size can influence one’s perception of the width of a door
how is vision used for locomotion
used to locomote through the environment safely + efficiently
**
auditory or visual information is processed faster
auditory
spike
another term for action potential
interspike interval (ISI)
the time in between action potentials
interneuron
completely oriented with the spinal cord within CNS
-inhibit/excite the interaction between afferent/efferent signals
how much if the CNS is interneurons
99%
efferent neuron
projects from spinal cord to muscle
other names for efferent neuron
-alpha motor neuron
-somatic motor neuron
afferent neuron
conveys sensory information to CNS from stimuli in periphery
example of afferent neuron
nociceptors or free nerve endings indicating noxious stimuli
**
dorsal root ganglion
where sensory information enters INTO
**
ventral root ganglion
where efferent neurons travel OUT through
proprioceptors
sensors that provide proprioceptive information about movement of the body
**
muscle spindles
-provides rapid feedback about changes in muscle length
-tells us about muscle stretch
-attaches to CT in muscle; arranged parallel with muscle fibers
primary muscle spindles
1a afferents
-tells us about rate of change in muscle stretch
-stretching a muscle leads to an increase in discharge of APs from 1a afferents
secondary muscle spindles
2a afferents
-tells us about absolute change in stretch
**
Golgi tendon organs
1b afferents
-tells us about muscle force/tension production
-GTOs only have afferent/sensory connections
-arranged in series with muscle fibers
-each motor unit can engage 1-6 GTOs
smaller intervals beween APs/spikes = less/more force
more force
describe rate that GTOs discharge APs in relation to muscle force
linear
what tells us about muscle FORCE/TENSION
GTOs
what tells us about muscle STRETCH
muscle spindles
**
GTOs regulate muscle force/tension via which type of system
negative feedback system
-increased GTO leads to excitation of 1b inhibitory interneuron -> inhibits alpha motor neuron of agonist muscle + excites alpha motor neuron of antagonist muscle
reflexive closed-loop control
-says reflexes are non-conscious mechanisms, meaning we don’t have to go all the way up to the brain to make a movement response
-the information goes up to the brain eventually, but it takes a few milliseconds to do so; reaction occurs before the brain is even aware of it
Dewhurst experiment
-shows muscle mechanisms by looking at EMG that tells us how far off we are from the target we have for a particular movement
-shows that processing takes some time BUT you can see that the arm automatically responds to the load that has been added
reflexes
-fast, automatic
-no cognitive processing
-protect bodily harm
feedforward motor control
-a strategy that our neuromuscular systems implement so we can get our body ready for movement + feedback for controlling movement
-it readies the system for what is about to happen but also readies the system for feedback from the movement
corollary discharge
advance information
-synonymous with efference copy
efferent copy
advance information
-synonymous with corollary discharge
what are saccades implemented for
implemented for using visual feedback
-we can look + plan ahead to where body is going to end up in space to ensure it is safe
