P/S Flashcards
Sensory Adaptation
downregulation of a receptor over time due to being overstimulated
1. Hearing: inner ear will maintain contraction
2. Touch: temperature receptors desensitized
3. Smell: receptors get desensitized
4. Proprioreception: Body will acclimate to being off balanced by finding new equilibrium
5. Sight: eyes will adapt to high or low light conditions
Weber’s law
Law of the just noticeable difference (JND)
- Threshold where you’re able to detect ∆es in sensation
- Ex.) adding 0.5 lbs to 5 lbs vs 0.5 lbs to 200 lbs
Absolute Threshold of sensation
Stimulus needed to detect a particular stimulus 50% of the time
- Can depend on the individual and how primed they are
Subliminal stimuli
stimuli below the absolute threshold
Vestibular system f(x)
balance and spatial orientation
- Focus on the inner ear which contains the semicircular canals (detector) and endolymph (liquid)
- Shifts can be detected which can result in dizziness
Signal Detection Theory
how we make decisions under periods of uncertainty (discerning what stimuli is “important”)
- We recognize important stimuli and unimportant “noise”
Bottom up processing
stimulus influences out perception
- we process sensory info as it comes in
- Ex) we perceive small pieces of info and put them together
Top-down processing
background info informs our perception
- our perception is driven by cognition
- Ex) we know what we are looking for
Gestalt’s principles
- similarity: items that are similar are grouped together
- Pragnanz: reality is organized into simpler forms (seeing olympic symbol vs 5 rings)
- proximity: objects close together are grouped together
- continuity: lines follow the smoothest path
- closure: objects seen together are seen as a whole
Structure of the eye
- cornea: transparent sheet of tissue that focuses the eye
- anterior chamber: contains fluid that maintains shape of eye
- lens: bends light so it goes to the back of the eye
- ciliary muscle: responsible for eye movement
- vitreous chamber: filled w/ vitreous jelly and provide pressure to the eyeball
- retina: filled with photoreceptors; rods and cones
- choroid: helps to supply oxygen to the eye w/ its blood vessels
Rods (eye)
detect light
Cones (eye)
detect color
Phototransduction cascade
- Light hits retinal and causes a ∆ in conformation of larger protein rhodopsin
- Transducin, bound to rhodopsin, will unbind and bind phosphodiesterase (PDE)
- PDE converts cGMP to GMP
- low [cGMP] results in low Na+ entering into the cell, causing hyperpolarization and reduced glutamate activity
- Bipolar cell is no longer inhibited by glutamate and the optic nerve sends an impulse to the brain
Rod vs cone recovery time
Rods have slow recovery time, cones have a quick recovery time
Parallel processing
See everything @ the same time, and process what’s important from what’s not important
- see a stop sign and a Taco Bell but respond to sign Bc it’s more important
Sound is detected through
1.
2.
- pressurized sound waves
- hair cells
Bones in eardrum
malleus, incus, stapes
How does sound get transmitted from ear to brain
Fluid in the cochlea also moves back and forth in accordance w/ sound waves
- sound waves move the hairs around, which cause K+ channels to open, allowing K to flow into the cells
- Once K+ enters into the cells, Ca2+ also enters the cells and can begin the AP to activate the auditory nerve
What is the hearing threshold?
20-20,000 Hz
Basilar tuning
Varying hair cells in the cochlea are used to differentiate differing fq of noise
Tonotypical mapping
The “map” of sounds the brain makes based on its differences in fq
Somatosensation
physiological mechanism by which we manifest physical stimuli and perceive its feeling as touch, pressure and pain
Types of somatosensation
1.)
2.)
3.)
4.)
- Temperature
- Pressure (mechanoreception)
- Pain (nociception)
- Position and balance (proprioception)
Sensory amplification
upregulation in perception of stimulus