(*Unfinished) 6A: Sensing the environment Flashcards
1. Sensory Processing 2. Vision 3. Hearing 4. Other Senses 5. Perception
Sensation
Ability to detect or sense the physical qualities of our environment
Sensory threshold
Weakest stimulus an organism can detect a sensation
Absolute threshold
Smallest detectable level of a stimulus
What types of thresholds are there?
- Sensory
- Absolute
- Difference
Absolute threshold is the most important
Perceiver’s Response to Stimulus:
Stimulus present, Perceiver’s response “yes”
Hit
Perceiver’s Response to Stimulus:
Stimulus present, Perceiver’s response “No”
Miss
Perceiver’s Response to Stimulus:
Stimulus absent, Perceiver’s response “Yes”
False alarm
Perceiver’s Response to Stimulus:
Stimulus absent, Perceiver’s response “No”
Correct rejection
Difference threshold
The minimum amount of change in sensory stimulation needed to recognize that a change has occurred
What is difference threshold also known as?
Just-noticeable difference (JND)
Just-noticeable difference (JND)
The minimum amount by which stimulus intensity must cbe changed to produce a noticeable variation in sensory experience
Weber’s Law
The difference threshold is proportional to the magnitude of the stimulus
* ΔI = Difference in threshold
* I = Initial stimulus
Psychophysics
The branch of psychology that deals with the relationships between physical stimuli and mental phenomena
Signal detection theory
The detection of a stimulus depends on both the intensity of the stimulus and the physical/psychological state of the individual
Sensory adaptation
Happens when our senses no longer perceive a stimulus because of our sensory receptor’s continuous contact with it
Sensory interaction
A phenomenon in which one sensory modality affects another
E.x. Hearing affecting vision
What are the 4 primary stimuli that sensory receptors respond to?
List the names of the receptors corresponding to each stimuli
- Chemicals
- Temperature
- Pressure
- Light
- Chemicals - Chemoreceptors
- Temperature - Thermoreceptors
- Pressure - Mechanoreceptors
- Light - Photoreceptors
Cutaneous touch receptor
A type of sensory recceptor found in the dermis or epidermis of the skin
Muscle spindle
Sensory receptors within the belly of a muscle that primarily detect changes in the length of this muscle
Match stimuli to receptor:
Electric fields, salinity, and temperature
Apmullae of Lorenzini
Primarily functions as electroreceptors
Match stimuli to receptor:
Pressure in blood vessels
Baroreceptors
Match stimuli to receptor:
Chemical stimuli
Chemoreceptors
Match stimuli to receptor:
Electromagnetic radiation
Electromagnetic radiation recceptors
Match stimuli to receptor:
Electrofields
Electroreceptors
Match stimuli to receptor:
Humidity
Hydroreceptors
Match stimuli to receptor:
Infrared radiation
Infrared receptors
Match stimuli to receptor:
Magnetic fields
Magnetoreceptors
Match stimuli to receptor:
Mechanical stress or strain
Mechanoreceptors
Match stimuli to receptor:
Damage or threat of damage to body tissues (leads to pain perception)
Nociceptors
Match stimuli to receptor:
Osmolarity of fluids
Osmoreceptors
Match stimuli to receptor:
Visible light
Photoreceptors
Match stimuli to receptor:
Sense of position
Proprioceptors
Match stimuli to receptor:
Temperature
Thermoreceptors
Match stimuli to receptor:
Ultraviolet radiation
Ultraviolet receptors
Retina
Inner surfacce of the back of the eye, where photoreceptive cells of the eye are located
Cornea
Front transparent layer of the eye
* Refract (bend) light to focus image on retina
Lens
Crystalline structure, a transparent convex structure behind the cornea
* Refract (bend) light to focus image on retina
Iris
A circular muscular ring lying between the lens and cornea
* Regulates amount of light entering the eye
Low light = Relaxation = Larger pupil
Bright light = Contraction = Smaller pupil
Presbyopia
Farsightedness, caused by loss of the flexibility of the lens
Hyperopia
Farsightedness, caused by an eyeball that is too short
Myopia
Nearsightedness, occurs when an eyeball is elongated
What are the two types of photoreceptors in the retina?
- Rods
- Cones
Rod cells
1. Location in retina
2. Optimal light conditions
3. Visual acuity
4. Color sensitivity
5. Type of vision
6. Number of types
7. Relative abundance
- Found around periphery
- Dim light (‘night vision’)
- Low resolution (many rods : one bipolar cell)
- All wavelengths
- Achromatic (black and white)
- One (all contain rhodopsin)
- Many
Cone cells
1. Location in retina
2. Optimal light conditions
3. Visual acuity
4. Color sensitivity
5. Type of vision
6. Number of types
7. Relative abundance
- Found around centre (fovea)
- Bright light (‘day vision’)
- High resolution (one cone : one bipolar cell)
- Certain wavelengths (red, green, blue)
- Color
- 3 different iodopsin pigments
- Fewer
Fovea
Region in the center back of the eye that is responsible for acute vision
The fovea has a high density of…
Cones
The the dark (e.x. looking at a star in the night sky), how do your eyes orient?
Orient so that the object falls in the peripheral vision (due to the higher number of rods, which respond better in dim conditions)
What makes up the optic nerves?
Myelinated axons of ganglion cells
What pathways do the axons of the optic nerves contribute to?
- Magnocellular (big cell) pathway
- Parvocellular (small cell) pathway
Magnocellular pathway
Carries information about form, movement, depth, and differences in brightness
Parvocellular pathway
Carries information on color and fine detail
True or False:
All visual information projects directly back into the brain
False, some other information crosses to the opposite side of the brain
Optic chiasma
Found at the base of the brain and coordinates information from both eyes
What are the two important visual routes?
- Retina to Thalamus
- Retina to Superior Colliculus
- Retina to Suprachiasmatic Nucleus (SCN)
The thalamus seres as the routing station for all incoming sensory impulses except…
Smell
Do the magnocellular and parvocellular distinctions remain intact in the thalamus?
Yes, there are different layers of the thalamus dedicated to each
When visual signals leave the thalamus, they travel to…
Primary visual cortex
* At rear of the brain
From the visual cortex, what are the streams that the information travel to?
- To parietal lobe (side of brain), carries magnocellular (“where”) information
- To temporal lobe, carries magnocellular (“where”) and parvocellular (“what”) information
Where is the superior colliculus located?
Midbrain
Superior colliculus
The primary area of the brain where eye movements are coordinated and integrated with auditory information
Suprachiasmatic nucleus (SCN)
A cluster of cells that is considered to be the body’s internal clock, which controls our circadian (day-long) cycle
Where is the SCN located?
Hypothalamus
The SCN sends information to the…
Pineal gland
* Important in sleep/wake patterns and annual cycles
What are the two types of bottom-up processing that take place in visual processing?
- Feature detection
- Parallel processing
Parallel processing
The use of multiple pathways to convey information about the same stimulus
Parallel processing starts at the level of the…
Bipolar and ganglion cells in the eye
How is information split into two pathways in parallel processing? What are the two pathways?
Through two types of ganglion cells
1. Motion pathway: Detects and processes information about motion
2. Form pathway: Concerned with form of stimuli (shape and color)
Where do the motion and form pathways in parallel processing project to?
Separate areas of the lateral geniculate nucleus (LGN) and visual cortex
Feature detection
A type of serial processing where increasingly complex aspects of the stimulus are processed in sequence
How does feature detection work essentially?
Takes information that reaches visual cortex
* Cells in visual cortex optimally respond to particular aspects of stimuli
* provide information concerning basic feautres of abjects
What types of stimulus are there in perception of light by the eye?
- Proximal stimulus
- Distal stimulus
Proximal stimulus
Physical stimulation that is available to be measured by an observer’s sensory apparatus
Distal stimulus
Any physical object or event in the external world that reflects light
Hearing
The transduction of sound waves into a neural signal that relies on the structures of the ear
What are the 3 parts of the ear?
- External ear
- Middle ear
- Internal ear
What is the external ear also known as?
Auricle
What is the auditory canal also known as?
External acoustic meatus
Tympanic membrane (tympanum)
Also known as the ear drum
* Innermost part of the outer ear
* Vibrates with the movement of air in sound waves
What is along the length of the auditory canal that contributes to the production of earwax?
Ceruminous glands
* Produce cerumen (earwax)
Cerumen functions
- Prevents small particles from finding their way to the tympanic membrane
- Prevents bacterial growth
- Waterproofs the auditory canal and tympanic membrane
- Deterrent to small insects
Ossicles
Three small bones that span the space of the middle ear
What are the ossicles?
Malleus, incus, stapes (roughly translates to hammer, anvil, and stirrup)
Which ossicle is attached to the tympanic membrane?
Malleus
Which ossicle is attached to the inner ear?
Stapes
Where in the inner ear is the stapes attached to?
Oval window
* Where the sound waves will be transferred to the inner ear
The middle ear is also connected to the pharynx through…
Auditory tube (Eustachian tube)
What is the purpose of the Eustachian tube?
Helps equalize air pressure across the tympanic membrane
Otitis media
Middle ear infection
Inner ear is entirely enclosed within the…
Temporal bone
What are the 3 regions of the inner ear?
- Cochlea
- Vestibule canals
- Semicircular canals
How do neural signals from the inner ear get relayed to the brainstem?
In separate fiber bundles, running together as the:
1. Vestibulocochlear nerve
2. Cranial nerve I/III
Oval window
An noval opening at the head of the cochlea connecting the middle and inner ear, through which sound vibrations of the stapes are trasmitted
Cochlea
The complex, spirally coiled, tapered cavity of the inner ear in which sound vibrations are converted into nerve impulses
What are the 3 chambers of the cochlea?
- Scala vestibuli (upper chamber)
- Scala tympani (lower chamber)
- Cochlear duct (middle chamber)
In the cochlea, what is on the other end of the tube from the oval window?
Round window
What is the end with the oval and round window known as in the cochlea?
Base
What is the inner end of the cochlea known as?
Apex
What frequencies are:
1. High-frequency waves
2. Medium-frequency waves
3. Low-frequency waves
- 1,500-20,000 Hz
- 600-1,500 Hz
- 200-600 Hz
What are the characteristics of the wave vibrations in the cochlea of different frequency waves?
- High frequency: Vibrations concentrated at the base
- Medium frequency: VIbrations distributed between base and apex
- Low frequency: Low magnitude vibrations
Spiral organ of Corti
The receptor organ for hearing and is located in the mammalian cochlea
Structure of organ of Corti
- Lower basilar membrane against the scala tympani
- Upper tectorial membrane within the cochlear duct
What is the nerve impulses created in the spiral organ of Corti transmitted into the brain by?
Vestibulocochlear nerve (cranial nerve VIII)
Besides hearing, what is the inner ear also responsible for?
Encoding information about equilibrium (sense of balance)
What are the two types of equilibrium?
- Static (gravitational) equilibrium
- Dynamic (rotational) equilibrium
Static (gravitational) equilibrium
Involves movement of the head with respect to gravity
Dynamic (rotational) equilibrium
Involves acceleration of the head in rotation, horizontal, and vertical movements
Where does the information for static and dynamic equilibrium come from?
Utricle and Saccule
* Within the vestibule
Utricle
The part of the membranous labyrinth of the ear into which the semicircular canals open and that contains the macula utriculi
Saccule
A little sac; specifically, the smaller chamber of the membranous labyrinth of the ear
What do each utricle and saccule contain?
Macula
Macula
The vestibule is a region of the inner ear which contains the saccule and the utricle, each of which contain a macula to detect linear acceleration
How are the maculae oriented to one another?
90 degrees
* So that they respond to different planes
