Duck Flashcards
Scattered through our organs are various _________that respond to stimuli in the internal or external environment of the organism
sensory receptors
All input to the CNS arrives in the same form as nerve impulses via
sensory neuron
are the physiological capacities within an organism that provide the inputs for perception
Senses
The information that the brain derives from sensory input is based on the frequency and pattern with which these impulses arrive on the identity of specific transmitting neuron
T or F
True
Topognosis aka….
Touch Localization
refers to the ability to localize stimuli to parts of the body
Touch Localization
occurs when the brain associates touch perception with sensory
nerve endings of a specific location on the ski
Touch Localization
🞂 due to differential density of distribution of the specific nerve
endings, touch sensitivity varies in one specific body regions
T or F
F
Different
T or R
sensitivity is greater in areas of the body with a high density of sensory nerve endings
T
Touch Discrimination is aka
Two-point discrimination
refers to the ability of the peripheral sensory nerves to recognize simultaneous stimulation by two blunt points (Walker, et al., 1990)
🞂 the point at which the patient can no longer differentiate one from two points once the two points are moved progressively closer
Touch Discrimination
TWO-POINT DISCRIMINATION DEPENDS ON:
◦ Activating two separate populations of neurons
◦ The receptive fields must be small
◦ The receptors must be densely packed in a sensitive area, so that two points very close together activate different receptors
Mechanisms of Touch Localization
Stimulus
Sensory Receptors
Afferent Nerve
CNS
Factors Affecting Sensitivity
◦ FACTORS:
HIGH
🞄 the large brain space devoted to
perception of touch in skin areas
🞄 the high density of touch sensory nerve fibers and receptor endings in a particular skin areas
◦ Glabrous (smooth and not hairy) areas of the skin are richly endowed with nerve endings which make them very sensitive (Culberson, 2006)
◦ i.e. fingertips and lips
LOW
◦ FACTORS:
🞄 less brain space in the cortex
🞄 lower density of sensory fibers and
receptor endings
◦ Hairy skin areas have fewer endings and different kinds with a low density of touch receptors which make them less sensitive to touch (Culberson, 2006).
◦ i.e. skin of the back and trunk
- Due to the large amount of mechanoreceptors specialized to provide information to the central nervous system about touch, this makes
the skin area to be highly
sensitive wherein even weak mechanical stimulation of the skin induces them to produce action potentials (Purves, et al., 2001).
true
Left Hemisphere section receives input from the body’s right side
for INPUT
Sensory Cortex
Left Hemisphere section controld the body’s right
OUTPUT
Motor Cortex
SOMATIC SENSORY RECEPTOR TYPES
Meissner’s Corpuscles
Pacinian C
Ruffini C
Hair Follicles
Merkel Complex
Free Nerve Ending
◦ Some are touch-sensitive (mechanoreceptors), while others are strictly pain-
sensitive (nociceptors).
◦ Others are temperature-sensitive (thermoreceptors) may be either cold- sensitive or heat-sensitive.
◦ Commonly found in hairy and smooth (glabrous) skin, cornea of the eye, pulp of teeth, mucous membranes, and many other locations.
Free nerve-endings
◦ Some are touch-sensitive
mechanoreceptors
others are strictly pain-
sensitive (
nociceptors
◦ Others are temperature-sensitive
thermoreceptors
◦ Commonly found in hairy and smooth (glabrous) skin, cornea of the eye, pulp of teeth, mucous membranes, and many other locations.
Free nerve-endings
◦ encapsulated and sensitive to pressure and vibration stimuli
Pacinian corpuscles
◦ found in hairy and smooth skin
Merkel’s discs/Merkel’s cells
◦ sensitive to touch and pressure
◦ important in localizing touch sensation to different areas of the
body
Merkel’s discs/Merkel’s cells
◦ very important in touch localization and texture discrimination
Meissner’s corpuscles
◦ abundant in smooth skin of toes, fingertips, palms, and soles of the feet.
Meissner’s corpuscles
◦ very sensitive to touch
Meissner’s corpuscles
◦ very sensitive to hair displacement
🞂 Hair follicle endings
the organism’s ability to determine the location of a sound and where it originates from directly (Alleydog.com, 2016).
sound localization
surrounds an observer & exists wherever there is sound
auditory space
how Sounds are localized
Distance coordinates
Azimuth coordinates
Elevation coordinates
Sound localization: position left
to right)
azimuth coordinate
Sound localization: position from observer
Distance coordinates
Sound localization: position up & down
Elevation coordinates
location cues based on the comparison of the signals received by the left and right ears
Azimuth Binaural Cues
2 binary cues on Auditory localization
- Interaural Time Difference (ITD)
- Interaural Intensity Difference (IID)
represents the measurement of the level of intensity which decreases with distance
Interaural Intensity Difference (IID)
produced because the ‘shadowing’ effect of the head prevents some of the incoming sound energy from reaching the far ear
Head Shadow Effect
the delay that a listener perceives between the time that a
sound reaches one ear and the time that it reaches the other
cues give information regarding the angular direction of a
source.
- If the s
- Interaural Time Difference (ITD)
- If the source is directly in front or behind the listener, the sound will reach both ears at the same time and the ITD will be 0.
- When the source is to the side of the listener, the times will differ
- Interaural Time Difference (ITD)
Will localization will be impaired if one is malfunctioning?
Yes
Unilateral hearing loss greatly affects sound localization because of the head shadow effect (allows perception of different sound volumes between ears and sounds partially blocked by the head) (D, Alessandro, 2011).
Experiment on Blind spot
Mariotte’ experiment
Region of retina where axons of ganglion cells exit to form optic nerve
blind spot
🞂 Corresponds with optic disk (regions where optic nerve leaves and blood vessels enter the eye.
Blindspot
No photoreceptors present thus no visual information can be transduced
Blindspot
read
central region of retina, provides clearest vision. Only cones are present and packed together.
fovea
is located about 15 degrees on the nasal side of the fovea.
blind spot
overlying cellular layers and blood vessels are displaced so that light rays are subject to a minimum of scattering before they strike the outer segments of the cones
read
also called ghost image or image-burn in.
afterimage
-occurs after staring at an original image for a period of time then suddenly looking away at a blank paper
afterimage
Explained as the adaptation of human retina’s photo-receptor cells.
afterimage
transform light in the form of photon energy into electric signal.
Receptors
change in opsin concentration
Photoreceptor kinetics
2 theory
trichromatic theory
opponent process theory
suggests that our ability to perceive color is controlled by three receptor complexes with opposing actions. These three receptors complexes are the red-green complex, the blue- yellow complex and the black-white complex.
Opponent Process Theory
Fits with afterimages, color blindness and evolution of color vision.
ewan
labyrinthine reflexes
vestibular apparatus
macula of Utricle and Saccule
Static Equilibrium
hotdog
Vestibular mechanisms for stabilizing eyes
1.Detection of Rotation
2. Inhibition of extraocular muscles on one side & Excitation od extraocular muscles on the other side
3. Compensating eye movement
Experiment for Equilibrium
Rotating Chair Experiment
Search for Dynamic Equilibrium
search
illusory movements of objects
Oscillopsia
the feeling that the surroundings are moving
Vertigo
feet says ground is steady, eyes says the surroundings are moving. Conflicting signals can cause motion sickness.
Motion Sickness
Position senses or the sense of the physical state of body
Proprioception
Involves somatosensory receptors
◦ skin tactile receptors
◦ deep receptors
◦ muscle spindles
What’s mechanoreceptors
May high sensitivity kineme
a sense organ or cell that responds to mechanical stimuli such as touch or sound.
Positioning of body segments with respect to each other and the environment
spacial orientation
Spatial orientation Depends on information from:
◦ Somatosensory (Proprioceptive) receptors
◦ Visual system
◦ Vestibular system
🞂 Requires input from proprioception and vision
reaching movement
Identifies target location, distance, depth
🞂 Position of limb
🞂 Visual feedback from moving limb
vision and action
Provides information of initial position of limbs
🞂 Assists in coordination of movement
🞂 Involves somatosensory receptors
Limb proprioception
Muscle Spindle Receptor
are encapsulated sensory receptors which inform the brain about changes in the length of muscles
Golgi tendon Organ
is a proprioceptor – a type of sensory receptor that senses changes in muscle tension.
Others Somatosensory Receptors
Joint capsule receptors
Tactile
◦ Ruffini’s endings (SA2 fibers) detect skin stretch
◦ Pacinian type I may interfere with movement detection
Tactile
◦ Possibly finger joint movement (Proske and Gandevia, 2012) and hand shape (Kandel et al., 2013)
Joint capsule receptors
Sensory Pathways
- The dorsal column- medial lemniscal system
- Somatosensory areas of cerebral cortex
◦ One of the parallel pathways carrying somatosensory impulses to the thalamus
The dorsal column- medial lemniscal system
goal-directed movement
Eyes closed
Eyes open
◦ proprioceptive and visual information available
◦ increases accuracy of target perception
◦ speed requirement may discourage guiding behavior
Eyes open
◦ visual information absent
◦ target perception less accurate
Eyes closed
Joints make body mechanically unstable
🞂 Upright stance is maintained through muscle activation
🞂 Integrates proprioceptive, vestibular, and visual inputs
Postural Control
🞂 Center of mass depends
on postural orientation
🞂 Base of support defined
by contact with surface
Balance
◦ Bring back center of mass
within base of support
◦ Expand base of support
Corrective behavior:
directional turning curve
A turn is a change in direction that is sharper than a curve. It involves a more abrupt change in the path of travel, often at a right angle or close to it.
process of muscle activation
check on the ppt
Provide information on muscle stretch, muscle force, and directionally specific pressure on foot soles
proprioception
prioception relies on
la afferent
lb afferent
Forms a neural map of body segments
pro prioception
Golgi tendon organs
lb afferent
muscle spindles
la afferent
Informs brain of:
◦ direction of gravity
◦ velocity of head rotation
🞂 Influence tuning of directional response
vestibular information
Provides orientation and motion information
🞂 Cannot distinguish between self motion and object motion
vision
This 4 provides control
Spinal cord
🞂 Brain stem and cerebellum
🞂 Spinocerebellum and basal ganglia
🞂 Cerebral cortex
◦ Anticipatory postural adjustment
◦ Antigravity support
Spinal cord
◦ Integration of sensory signals
Brain stem and cerebellum
◦ Adaptation of posture
🞂 Spinocerebellum and basal ganglia
◦ Anticipatory postural adjustment with voluntary movement (supplementary motor area)
◦ Possibly perception of body verticality (temporoparietal cortex)
◦ Requires attention and is affected by emotional state
Cerebral cortex
Greater sample entropy means less regular COP fluctuations
🞂 Dancers seem to devote less attention to maintaining posture than non-dancers
(Stins et al., 2009
attention demand
