Psychology Condense 1 PDF

Processing the Environment Sensory Perception Visual Cues - Depth, Form, Motion, Constancy \- Binocular Cues - Retinal disparity (eyes are 2.5 inches apart), Convergence -- things far away, eyes are relaxed. Things close to us, eyes contract. \- Monocular Cues - relative size, interposition (ove...

Processing the Environment Sensory Perception Visual Cues - Depth, Form, Motion, Constancy \- Binocular Cues - Retinal disparity (eyes are 2.5 inches apart), Convergence -- things far away, eyes are relaxed. Things close to us, eyes contract. \- Monocular Cues - relative size, interposition (overlap), relative height (things higher are farther away), shading and contour, motion parallax (things farther away move slower), Constancy -- our perception of object doesn't change even if it looks different on retina( Ex. size constancy, shape constancy, color constancy) Sensory Adaptation \- Hearing - inner ear muscle: higher noise = contract; Touch - temperature receptors desensitized; Smell -- desensitized to molecules; Proprioception -- mice raised upside down would accommodate over time, and flip it over; Sight -- down (ex. Light adaptation, pupils constrict, rods and cones become desensitized to light) and upregulation (dark adaptation, pupils dilate) Weber's Law \- 2 vs. 2.05 lb weight feel the same but 2 vs. 2.2 lb weight difference would be noticeable. \- The threshold at which you're able to notice a change in any sensation is the just noticeable difference (JND) \- I = intensity of stimulus (2 or 5 lb), delta I = JND (0.2 or 0.5). \- Weber's Law is delta I to intensity is constant: Delta I/I = k (Weber's Law) \- If we take Weber's Law and rearrange it, we can see that it predicts a linear relationship bet · Delta I = Ik. · If you plot I against delta I it's constant Absolute threshold of sensation \- The minimum intensity of stimulus needed to detect a particular stimulus 50% of the time \- Not the same as the difference threshold (JND) \- Absolute threshold can be influenced by a \# of factors (Expectations, Experience (how familiar you are with it), Motivation, Alertness) \- Subliminal stimuli -- stimuli below the absolute threshold. The Vestibular System - Balance and spatial orientation \- Focus on inner ear - in particular the semicircular canals (posterior, lateral, and anterior) \- Canal is filled with endolymph, and movement causes it to shift -- allows us to detect what direction our head is moving in, and the strength of rotation. \- Otolithic organs (utricle and saccule) help us to detect linear acceleration and head positioning. In these are Ca 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 an action potential. \- Also contribute to dizziness and vertigo - Endolymph doesn't stop spinning the same time as we do, so it continues moving and indicates to brain we're still moving even when we've stopped -- results in feeling of dizziness. Signal Detection Theory \- Looks at how we make decision under conditions of uncertainty -- discerning between important stimuli and unimportant "noise" - At what point can we detect a signal Strength of a signal is variable d', and c is strategy \- d': hit \> miss (strong signal), miss \ neural impulse, by a photoreceptor What is light? \- Electromagnetic wave part of a large spectrum \- EM spectrum contains everything from gamma rays to AM/FM waves. Visible light is in the middle · Violet (400nm) -- Red (700nm) \- The Sun is one of most common sources of light Light enters pupil and goes to retina, which contains rods and cones \- There are 120 million rods, for night vision · Light comes in, goes through pupil, and hits rod. Normally rod 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. \- There are 6-7 million cones · 3 types: red, green, blue · Almost all cones are centered in fovea Phototransduction Cascade -- when light hits rods and cones \- Retina is made off a bunch of dif cells -- rods and cones. \- As soon as light is presented to him, he takes light and converts it to neural impulse. Normally turned on, but when light hits it's turned off. PTC is a set of steps that turn it off. \- Inside the rod are a lot of disks stacked on top of one another. \- A lot of proteins in the disks. One is rhodopsin, a multimeric protein with 7 discs, which contains a small molecule called retinal (11-cis retinal). When light hits, it can hit the retinal, and causes it to change conformation from bent to straight. \- When the retina changes shape, rhodopsin changes shape. \- That begins this cascade of events -- there's a molecule in green called transducin made of 3 diff parts -- alpha, beta, gamma · Transducin breaks from rhodopsin, and the alpha part comes to disk and binds to phosphodiesterase (PDE). · PDE takes cGMP and converts it to regular GMP. Na+ channels allow Na+ ions to come in, but for this channel to open, need cGMP bound. As cGMP decreases, Na channels closes. · As less Na+ enters the cell, rods hyperpolarize and turn off. Glutamate is no longer released, and no longer inhibits ON bipolar cells (it's excitatory to OFF bipolar cells). · So bipolar cells turn on. This activates retinal ganglion cell which sends signal to optic nerve, then to brain. Photoreceptors (Rods and Cones) \- A photoreceptor is a specialized nerve that can take light and convert to neural impulse. \- Inside rod are optic discs, which are large membrane bound structures -- thousands of them. In membrane of each optic disc are proteins that fire APs to the brain. \- Cones are also specialized nerves with same internal structure as rod. \- Rods contain rhodopsin, cones have similar protein photopsin. \- If light hits a rhodopsin, will trigger the phototransduction cascade. Same process happens in a cone. \- Differences: · 120 M rods vs. 6 million cones. · Cones are concentrated in the fovea. · Rods are 1000x more sensitive to light than cones. Better at detecting light -- telling us whether light is present, ie. BW vision · Cones are less sensitive but detect color (60% Red, 30% Green, 10% Blue) · Rods have slow recovery time, cones have fast recovery time. Takes a while to adjust to dark -- rods need to be reactivated. Photoreceptor Distribution in Retina \- Where optic nerve connects to retina, blind spot -- no cones or rods. \- Rods are found mostly in periphery. \- Cones are found throughout the fovea, and few in rest of eye. \- If we zoom in on fovea -- no axons in way of light, so get higher resolution. If light hits periphery, light has to go through bundle of axons and some energy lost. So at fovea light hits cones directly. Visual Field Processing How our brain makes sense of what we're looking at. Right side of body controlled by left side, vice versa. \- How does it work in vision? · All right visual field goes to left side of brain, all left visual field goes to right side of brain. Feature Detection and Parallel Processing \- Color (cones, trichromatic theory of color vision), form (parvocellular pathway -- good at spatial resolution, but poor temporal), motion (magnocellular pathway, has high temporal resolution and poor spatial resolution, no color) \- Parallel processing -- see all at same time; simultaneous processing of incoming stimuli that differs in quality Sound (Audition) Auditory Structure -- Part 1 \- Need 1) pressurized sound wave and 2) hair cell \- Ex. In between your hands are a bunch of air molecules, and suddenly hands move towards each other, so space is a lot smaller. \- Air molecules are pressurized and try to escape, creating areas of high and low pressure -- known as sound waves · Sound waves can be far apart or close together · How close peaks are is the frequency. · Different noises have different sounds · You can listen to different frequencies at same time -- if you add dif frequency waves together, get weird frequency. Ear has to break this up. Able to do that because sound waves travel different lengths along cochlea. Hair cells -- first hit outer part of ear, known as the pinna. Then go to external auditory meatus (aka auditory canal). Then hit the tympanic membrane (Eardrum) \- As pressurized wave hits eardrum, it vibrates back and forth, causes these 3 bones to vibrate -- malleus, incus, and stapes. \- Stapes is attached to oval window (aka elliptical window). As it gets pushed, it pushes fluid and causes it to go around cochlea. At tip of cochea, it can only go back, but goes to the round window and pushes it out. \- Reason doesn't go back to oval window, is because in middle of cochlea is the organ of Corti (basilar and the tectorial membrane). \- Happens until energy of sound wave is dissipated. Meanwhile hair cells in cochlea move back and forth and send info to auditory nerve. \- General classification -- · From pinna to tympanic membrane is the outer/external ear. · From malleus to stapes, middle ear. · Cochlea and semicircular canals is the inner ear. Auditory Structure -- Part 2 \- Focus on cochlea and inner ear \- Let's unroll the cochlea. \- Stapes -- moving back and forth at same frequency as stimulus. It pushes the elliptical window back and forth. · There's fluid inside the cochlea which gets pushed around cochlea, and comes back around. Organ of Corti splits cochlea into 2. \- Cross section of Organ of Corti · Upper and lower membrane, and little hair cells. As fluid flows around the organ it causes hair cells to move back and forth. · The hair bundle is made of little filaments. Each filament is called a kinocilium. · Tip of each kinocilium is connected by a tip link. · Tip link is attached to gate of K channel, so when get pushed back and forth they stretch and allows K to flow inside the cell. · Ca cells get activated when K is inside, so Ca also gets activated, and causes AP in a spiral ganglion cell which then activates the auditory nerve. Auditory Processing Brain relies on cochlea to differentiate between 2 different sounds. \- Base drum has low frequency, whereas bees have high frequency. \- We can hear between 20-20000Hz. \- Brain also uses basilar tuning -- there are varying hair cells in cochlea. Hair cells at base of cochlea are activated by high frequency sounds, and those at apex by low frequency sounds. · Apex = 25 Hz, base = 1600 Hz. · Only certain hair cells are activated and send AP to the brain -- primary auditory cortex receives all info from cochlea. · Primary auditory cortex is also sensitive to various frequencies in dif locations. · So with basilar tuning, brain can distinguish dif frequencies -- tonotypical mapping. Somatosensation Somatosensation \- Types of Sensation, Intensity, Timing, and Location \- Types: Temperature (thermoception), pressure (mechanoception), pain (nociception), and position (proprioception) \- Timing: Non-adapting, slow-adapting, fast-adapting. \- Location: Location-specific nerves to brain Sensory Adaptation and Amplification Adaptation is change over time of receptor to a constant stimulus -- downregulation \- Ex. As you push down with hand, receptors experience constant pressure. But after few seconds receptors no longer fire. \- Important bc if cell is overexcited cell can die. Ex. If too much pain signal in pain receptor (capsaicin), cell can die. Amplification is upregulation · Ex. Light hits photoreceptor in eye and can cause cell to fire. When cell fires AP, can be connected to 2 cells which also fire AP, and so on. Somatosensory Homunculus \- Your brain has a map of your body -- the cortex. \- This part of cortex is the sensory cortex -- contains the homunculus. \- Info from body all ends up in this somatosensory cortex. \- If there was a brain tumor, to figure out what part it's in neurosurgeons can touch diff. parts of cortex and stimulate them. If surgeon touches part of cortex patients can say they feel it. Do it to make sure they aren't removing parts in sensation. \- This creates topological map of body in the cortex.