psych soc KA

Visual cues allows us to perceptually organize by taking into account the following cues:

- depth

- form

- motion

- constancy

Describe retinal disparity.

- Eyes are about 2.5 inches apart which allows humans to get slightly different views of objects of world around.

- gives humans an idea on depth

What is convergence?

- gives humans an idea of depth as well based on how much eyeballs are turned. gives humans a sense of depth

When are the muscles of the eye relaxed and contracted?

- things far away: muscles of eyes relaxed

- things close to us: muscles of eyes contract

Describe binocular cues.

- humans have two eyes which allow them to receive visual cues from the environment

- depth

Describe monocular cues.

- humans have visual cues that they receive which they do not need two eyes for

What do monocular cues provide?

- give humans a sense of form of an object

What senses of form do monocular cues provide?

- Relative size: the closer and object it is perceived as being bigger

- Interposition (overlap): perception that one object is in front of another. an object that is in the front is closer

- Relative height: things higher are perceived to be farther away than those that are lower

- Shading & contour: using light and shadows to perceive form depth/contours - crater/mountain

What type of cues allow us to sense motion? What type of sense exactly?

Monocular cues

- Motion parallax: "relative motion" things farther away move slower, closer moves faster

What type of cues allow us to sense constancy?

- monocular

- out perception of object doesn't change even if the image cast on the retina is different. Different types of constancy include size constancy, shape constancy, color constancy

Describe size constancy.

- one that appears larger because its closer, we still think it is the same size

Describe shape constancy

- a changing shape still maintains the same shape perception

- ex: a door opening means the shape is changing. but we still believe the door is a rectangle

Describe color constancy.

- despite changes in lighting which change the image color falling on our retina, we understand (perceive) that the object is the same color

What is sensory adaptation?

Our senses are adaptable and they can change their sensitivity to stimuli

What are the 5 types of sensory adaptation?

- hearing adaptation

- touch

- smell

- proprioception

- sight

Describe hearing adaptation in regards to sensory adaptation.

- inner ear muscle: higher noise = muscle contract (this dampens vibrations in inner ear, protecting the ear drum). Takes a few seconds to kick in. So does not work for immediate noises like a gun shot, bit it works for being at a rock concert for an entire afternoon

Describe touch in regards to sensory adaptation.

- temperature receptors desensitized over time

Describe smell in regards to sensory adaptation

- desensitized receptors in your nose to molecule sensory information over time

Describe proprioception in regards to sensory adaptation.

- the sense of the position of the body in space i.e. "sense of balance/where you are in space"

- experiment: goggles that make everything upside down and the perception of the world, and eventually you would accommodate over time, and flip it back over

Describe sight in regards to sensory adaptation

- down regulation or up regulation to light intensity

- down regulation: light adaptation. when it is bright out, pupils constrict (less light enters back of eye), and the desensitization of rods and cones become desensitized to light

- up regulation: dark regulation. pupils dilate-, rods and cones start synthesizing light sensitive molecules

What is Weber's Law?

- the threshold at which you're able to notice a change in any sensation is the just noticeable difference (JND)

- I=initial intensity of stimulus , change I= JND

- change I/initial intensity = k (constant)

- change I= IK

What is the absolute threshold of sensation?

- the minimum intensity of stimulus needed to detect a particular stimulus 50% of the time

Are the absolute threshold of sensation and just noticeable difference the same?

No, JND is the smallest difference that can be detected 50% of the time

What factors can influence absolute threshold?

- Expectations - ex: are you expecting a text

- Experience - ex: are you familiar of the phones text vibration sound

- Motivation - ex: are you interested in the response of the text

- Alertness - are you awake or drowsy ex: you will notice the text if you are awake

What are subliminal stimuli?

stimuli below the absolute threshold of sensation

What are the three different types of information we gather about somatosenstation?

- Intensity

- Timing

- Touch

What are the 4 types of somatosensation?

- Temperature (thermoception)

- Pressure (mechanoception)

- Pain (nociception)

- Position (proprioception)

Describe intensity in terms of somatosensation.

- how quickly neurons fire for us to notice

- slow = low intensity

- fast = high intensity

Describe timing in terms of somatosensation.

- neuron encodes 3 ways for timing: non adapting, fast adapting or slow adapting

- Non-adapting: neuron consistency fires at a constant rate

- Slow- adapting: neuron fires in beginning of stimulus and calms down after a while

- Fast-adapting: neuron fires as soon as stimulus starts..then stops firing. Starts again when stimulus stops.

Describe location in terms of somatosensation/

- location specific stimuli by nerves are sent to brain. relies on dermatomes

Describe the vestibular system.

- a type of sensation. balance & spatial orientation

- comes from both inner ear and limbs

How does the inner ear contribute to the vestibular system?

- the semicircular canals (posterior, lateral and anterior; each orthogonal to each other)

- canal is filled with endolymph, and when we rotate the fluids shift in the semicircular canals - allows us to detect how quickly the endolymph is moving we can determine the strength of rotation

- otolithic organs (utricle and saccule) helps us to detect linear acceleration and head positioning. In these are CaCO3 (calcium carbonate) crystals attached to hair cells in viscous gel. If we go from lying down to standing up, they move, and pull on hair cells, which triggers action potentials. These would not work very well without gravity. Buoyancy can have effects as well, particularly without visual cues on which way is up/down

- also contribute to dizziness and vertigo (when you or objects around you are moving when they are not)

- Endolymph doesn't stop spinning the same time as we do, so it continues moving and indicated to brain we're still moving even when we've stopped - we feel dizzy

What is the signal detection theory?

- looks at how we make decision under conditions of uncertainty - discerning between important stimuli and unimportant noise

According to the signal detection theory, for any signal, we have __

noise distribution (background)

What is bottom up processing?

begins with stimulus. stimulus influences what we perceive (our perception)

- no preconceived cognitive constructs of the stimulus (never seen it before)

- data driven. and the stimulus directs cognitive awareness of what you're looking at (object)

- inductive reasoning. always correct

What is top-down processing?

- uses background knowledge influences perception

- theory driven. perception influenced by our expectation

- deductive reasoning

- like: creating a cube when it is not there. not always correct

What are Gestalt Principles?

Tries to explain how we perceive things the way we do.

- Similarity: items similar to one another grouped together by brain

- Pragnanz: reality organized reduced to simplest form possible

- Proximity: objects that are close are grouped together.

- Continuity: lines are seen as following the smoothest path

- Closure: objects grouped together are seen as a whole. mind fills in missing information

- Symmetry: the mind perceives objects as being symmetrical and forming around a center point

What is the Law of Common Fate?

- For example, if there are an array of dots and half the dots are moving upward while the other half are moving downward, we would perceive the upward moving dots and the downward moving dots as two distinct units

What is the Law of Past Experiences?

- Implies that under some circumstances visual stimuli are categorized according to past experience. If two objects tend to be observed within close proximity, or small temporal intervals, the objects are more likely to be perceived together.

What are contextual effects?

- the context in which stimuli are presented and the processes of perceptual organization contribute to how people perceive those stimuli (and also that the context can establish the way in which stimuli are organized)

What is the conjunctiva?

thin layer of cells that lines the inside of your eyelids from the eye

What is the cornea?

transparent thick sheet of fibrous tissue, anterior 1/6th; starts to bend light, first part of eye light hits

What is the anterior chamber?

- space filled with aqueous humour, which provides pressure to maintain shape of eyeball; allows nutrients and minerals to supply cell of cornea/iris

What is the pupil?

- the opening in the middle of the iris

- the size of the pupil can get bigger/smaller based on the iris relaxing/contracting respectively. the pupil modulates the amount of light able to enter the eyeball

What is the iris?

gives the eye color. the muscle that constricts/relaxes to change the size of the pupil

What is the lens?

- bends the light so it goes to back of eyeball - focuses light specifically on the fovea of the retina. adjust how much it bends the light by changing its shape, using the suspensory ligaments

What are the suspensory ligaments?

attached to a ciliary muscle. these two things together form the ciliary body, which secretes the aqueous humor

What is the posterior chamber?

the area behind the iris to the back of the lens; also filled with aqueous humor

What is the vitreous chamber?

filled with vitreous humor, a jelly like substance to provide pressure to the eyeball and gives nutrients to the inside of the eyeball

What is the retina?

inside, back area filled with photoreceptors, where the ray of light is converted from a physical waveform to a electrochemical impulse that the brain can interpret

What is the macula?

- special part of the retina rich in cones, but there are also rods

What is the fovea?

a special part of the macula. completely covered in cones, no rods

- rest of the retina is covered in primarily rods

What are cones?

- detect color and discern high level of detail in what you are observing. cone shaped

What are rods?

detect light. rod shaped

What is the choroid?

pigmented black in humans, is a network of blood vessels that helps nourish the retina. It is black because all light is absorbed. Some animals have a different colored choroid which gives them better night vision.

What is the sclera?

- usually absorbs by the time the light gets to this. the whites of the eye, thick fibrous tissue that covers posterior 5/6th of eyeball (cornea covers the anterior 1/6).

- attachment point for muscles. extra layer of protection and structure of eyeball. lined with the conjunctiva

What is transmission?

the electrical activation of one neuron by another neuron

What is perception?

the conscious sensory experience of neural processing

What is processing?

the neural transformation of multiple neural signals into a perception

What is sensation?

requires a physical stimulus to be converted into a neural impluse

What is light?

- an electromagnetic wave

- EM spectrum : Violet (400nm) - Red (700nm)

After light enters the eye what happens?

- enters the pupil -> goes to the retina which contains rods and cones

Explain what happens when light hits a rod.

- there are 120 million rods for night vision

- light comes in, goes through pupil, and hits rod. Normally rods is turned on, but when light hits turns off

- when rod is off, it turns on a bipolar cell, which turns on a retinal ganglion cell, which goes into the optic nerve and enters the brain

Explain what happens when light hits a cone cell.

- there are 6-7 million cones

- 3 types: red, green, blue

- almost all cones are centered in fovea (details, which is the center of the macula)

- Phototransduction cascade

Explain the phototransduction cascade.

- what happens when light hits rod/cone

- light hits rods (which rod turns off) -> bipolar cell (turns on) -> retinal ganglion cell (turns on) -> optic nerve -> brain

- phototransduction cascade is the process of rod turning from on -> off

What are bipolar cells?

- are found in the retina

- these cels send visual signals from the rods and cones to the ganglion cells.

What are ganglion cells?

- are found in the retina

- bipolar cells send signals to the ganglion cells

What is the optic nerve?

- visual signals, after having been picked up by the rods and cones and transferred to bipolar cells to the ganglion cells, finally leave the eye through the optic nerve, which is really just the axons of the ganglion cells

What is the trichromatic theory of color vision?

- states that you have cones that are receptive to 3 colors: red, green and blue. These three colors are mixed together and you perceive color

What is the problem with the trichromatic theory of color?

- while our eyes can mix together, say red and yellow to make orange, we can't seem to mix red and green or blue and yellow.

- this can be explained by the opponent process theory of color vision

What is the opponent process theory of color vision?

- you have cones that perceive 4 colors: red, green, blue and yellow and that red and green cones oppose each other, as do blue and yellow cones.

- black and white sensitive cones are also opponents

- between these opponents, only one color can dominate at a time

Explain the steps of the phototransduction (detailed).

1. inside the rod are a lot of optic disks stacked on top of one another

2. a lot of proteins on the disks. one is rhodospin (on a cone the same protein is called photopsin), a multimeric protein with 7 discs, which contains a small molecule called retinal (11-cis retinal). When light hit, comes through pupil and hits the retinal, then it rods, some of the light his rhodospin (which contains the retina) and causes the retinal to change conformation from bent to straight conformation (11-trans retinal)

3. when retinal changes shape, rhodopsin changes shape (closely linked molecules). this begins cascade

4. there is a molecule called transducin made of 3 different parts - alpha, beta, gamma that is attached to the rhodopsin

5. when the rhodopsin changes shape, transducin breaks from the rhodospin, and alpha subunit binds to another disk protein called phosphodiesterase (PDE)

6. PDE takes cGMP and converts it to regular GMP [ So when light hits, lower concentration and increases concentration of GMP]

7. Lots of Na+ channels on the rods allow NA+ ions to come in
* cGMP bound to Na+ channel, keeps the channel open and hence "ON", as cGMP concentration decreases, Na+ channel closes and turns Off
* when Na+ channels become unbound of cGMP, less NA+ enters the cell, then cell hyperpolarization and turn off

8. next, bipolar cells (2 variants: on center and off center)
* when light hits rod, turned off -> on center bipolar cells active, off center bipolar cells inactive
* when on center bipolar cells turned on, this activates on center retinal ganglion cell, when sends signal to optic nerve to brain.
*when dark, rod is turned on-> on center bipolar cells inactive, off center bipolar cells active
*when off center bipolar cells turned on, this activates off center retinal ganglion cell, when sends signal to optic nerve to

When does photopic vision occur?

at high light levels

When does mesopic vision occur?

at dawn or dusk and involves both rods and cones

When does scotopic vision occur?

at very low light levels

Rods are _____ more sensitive to light than cones

1000x

What is the three color ratio of cones?

60% red, 30% green , 10% blue

What is feature detection?

When looking at an object, you need to break it down into its component features to make sense of what you are looking at.

- there are 3 things to consider when looking at any object color, form and motion

Explain color in terms of feature detection/

- cones

- trichromatic theory of color vision, 3 types of cones

- red (60%), green (30%), blue (10%)

- remember, red objects reflect red, green objects reflect green and blue objects reflect blue

Explain form in terms of feature detection.

- we need to figure out boundaries of the object and shape of the object

- parvocellular pathway: good at spatial resolution (boundaries and shape - high level of details), and color. But poor temporal (can't detect motion-only stationary)

- cones are responsible

Explain motion in terms of feature detection.

- magnocellular pathway: has high temporal resolution (think time, motion) resolution [encodes motion]. But has poor spatial resolution; now color.

- rods responsible

- acronym: motion = magnocellular pathway

What is parallel processing?

detect/focus all information (color, form, motion) at the same time

What are the two things we need for audition?

- pressurized sound wave (a stimuli)

- hair cell (a receptor, located in the cochlea)

What are sound waves?

- air molecules are pressurized and try to escape, creating areas of high and low pressure

- can be far apart or close together (wavelength: how close the peaks are)

- smaller wavelength = greater frequency

- higher wavelength (smaller frequency) = travel farther = penetrate deeper into the cochlea

In 10 steps, describe the sound (auditory waves) path:

1. first hit outer part of ear, known as the pinna

2. then the sound gets funneled from the pinna to the auditory canal (also known as external auditory meatus)

3. then from the auditory canal they hit the tympanic membrane (also called the eardrum)

4. As pressurized wave hits eardrum, it vibrates back and forth, causing 3 bones to vibrate in this order (ossicles)
i. malleus (hammer)
ii. incus (anvil)
iii. stapes (stirrup)

5. Stapes is attached to the oval window (aka elliptical window). the oval window then vibrates back n forth

6. as it gets vibrated, it pushes fluid and causes it to go in/around cochlea

7. at tip of cochlea (inner most part of the circle), where can the fluid now go? It can only go back, to the round window and pushes it out.

8. the reason it doesn't go back to the oval window is because in middle of the cochlea is a membrane called the organ of Corti (includes the basilar membrane and the tectorial membrane)

9. As hair cells move back n forth in the cochlea, electrical impulse is transported by the auditory nerve to the brain

10. the above process of fluid going around the cochlea keeps occurring till the energy of the sound wave dissipates and stops moving. occurs more = more hair cells vibrate

What is the place theory?

- our perception of sound depends on where each component frequency produces vibrations along the basilar membrane. By this theory, the pitch of a musical tone is determine by the places where the membrane vibrates, based on frequencies corresponding to the tonotopic organization of the primary auditory neurons

- one is able to hear different pitches because different sound waves trigger activity at different places along the cochlea's basilar membrane

Describe the upper membrane of the Organ of Corti.

- the hair cells are called the hair bundle and it is made of little filaments

- each filament is called a kinocilium

- tip of each kinocilium is connected by a tip link which is attached to gate of K+ channel

- when the tip links get pushed back and forth by endolymph movement, they stretch and allows K+ to flow inside the cell from the endolymph

- Ca2+ cells get activate when K+ is inside, so Ca2+ also flows into the cell, and causes an action potential, which then activated a spiral ganglion cell, which then activates the auditory nerve

The brain relies on the cochlea to differentiate between 2 different sounds how (how does auditory processing occur)?

- Basilar tuning: there are varying hair cells in cochlea and allows brain to distinguish between high and low frequency sounds.

- hair cells at base (start of cochlea) are activated by high frequency sounds

- hair cells at the apex (end of the cochlea) by low frequency sounds

-> long wavelengths travel farther

- The primary auditory cortex (part of the temporal lobe) received all info from cochlea. It is separated by regions which detect different frequencies

- so with basilar tuning, brain can distinguish diff frequencies - tonotopical mapping

Describe the somatosensory homunculus.

- a map of your body in your brain. information all comes to the "sensory strip"

- a topological map of the entire body in the cortex. different areas of the body have signals that go to different parts on this strip

- the sensory cortex contains the homunculus

- brain has information that comes from various parts of the body

How does proprioception work?

- tiny little receptor (known as a spindle) located in our muscles sends signals that go up to spinal cord and to the brain. Spindle has a protein that is sensitive to stretching

- sensors contract with muscles - so we are able to tell how contracted or relaxed every muscle is in our body

- cognitive awareness of your body in space is subconscious

Describe Kinaesthesia.

- movement of the body, behaviorally

Both nocicption and thermoception are ____

slow

Describe the TrypV1 receptor

- how we are able to sense temperature

- also sensitive to pain

- there are thousands of these in membranes. heat causes a conformational change (in physical structure )of the protein -> sends signal to the brain

What are the three types of nerve fibers?

- A-Beta fibres: fast ones are thick and covered in myelin (less resistance, high conductance

- A-Delta fibres: smaller diameter, less myelin

- C fibres: small diameter, unmyelinated (lingering sense of pain)

How does pain also change the conformation of receptors? Ex: eating hot foods

- capsaicin binds the TrypV1 receptor in your tongue and triggers the same response

What is the gate control theory of olfaction?

- theory of the processes of nociception

- asserts that non-painful input closes the gates to painful input, which prevents pain sensation from traveling to the CNS. Therefore, stimulation by non-noxious input is able to suppress pain

- fast blocks slow

- by Ronald Melzack and Patrick Wall

What are pheromones?

- a chemical signal released by 1 member of the species and sensed by another species to trigger an innate response

- important in animals- linked to mating, fighting and communication

When is a specialized part of the olfactory epithelium in animals?

- accessory olfactory epithelium: sends projections to the accessory olfactory bulb which then sends signals to the brain

Describe the structures within the accessory olfactory epithelium and its uses.

- within you have a structure called the vomeronasal system

- in the vomeronasal system, there are basal cells and apical cells which receptors at tips

- molecule will come in and activate receptor on basal cell/apical cell here. Basal cell sends axon through accessory olfactory bulb to glomerulus, then mitral or tufted cell which eventually goes to the amygdala

- amygdala is involved with emotion, aggression, mating, etc. In temporal love, also involved with memory/decision making, emotional reactions

- signal transduction is where signal binds to receptor, which binds to GPCR -> depolarization -> signals goes to brain

- humans have a vomeronasal organ, but no accessory olfactory bulb. As a result, we rely very little on phermones