Final Flashcards
What are the three types of coding?
Specific, Sparse and Population coding
What are the two types of stimulus?
Distal->in the environment
Proximal->on the receptors
What are the three methods to measure absolute threshold?
method of limits, adjustemnt and constant stimuli
Define macular degeneration and retinitis pigmentosa
macular degeneration->destroyed cone-rich fovea
retinitis pigmentosa->attack peripheral vision
What are the four visual problems?
Myopia (nearsightedness)-Inability to see distant object
Refractive myopia->cornea and lens bend light too much
Axial myopia->eyeball too long
Hyperopia (farsightedness)->Trouble seeing near objects
Eyeball too short
Presbyopia->Trouble seeing near objects due to aging (lens more rigid)
Astigmatism->multiple images on retina
Isomerization
bending of retinal when absorb light
Explain the process of dark adaptation
rod-cone break, visual pigment bleaching, visual pigment regeneration
detached retina
no more visual pigment regeneration
Purkinje shift
tendency for eyes to shirt toward blue at low light as part of dark adaptation–>because rods more sensitive to short wavelenght
What are the five cells in the retina?
photoreceptor cells->bipolar cells, ganglion cells
horizontal and amacrine cells
What is the difference in convergence between cones and rods?
Rods converges more than cones
Rods more sensitive->ganglion cells are more likely to fire because receive info from multiple cells
Cones more acuity->because less convergence
What did Hartline and Kuffler discovered?
ganglion cells receptive fileds and center-surround organization
Define lateral inhibition and edge enhancement
define chevreul illusion and Mach bands
Chevreul illusion->alter appearance of colors by placing them next to each other
Mach bands->fuzzy shadow border between light and dark
Explain the pathway from eye to the brain
Eye->optic nerve->optic chiasm->90% to lateral geniculate nucleus and 10% to superior colliculus->primary visual area/striate cortex/V1
What are the three types of cells find in the brain for vision?
Simple cells->receptive fields but side by side, respond to oriented lines
Complex cells->respond to moving oriented lines
End-stopped cells->moving corners or angles
selective rearing
if always presented with one type of stimulus, neurons for that stimulus will be more prevalent
–>experience-dependent plasticity
cortical magnification
more space is dedicated to info from fovea in cortex
Higher level neurons
in inferotemporal (IT) cortex
large receptive fields (faces and objects)
inverse projection problem
image on retine could come from infinite number of objects
viewpoint invariance
ability to recognize an object regardless of viewpoint
Pragnanz principle
simplicity gestalt principle
recognition by components theory (RBC)
Objects are composed of individual geometric components called geons
gist of scene
general description of type of scene
Can recognize a scene even when showed for 250ms
Li fei-fei’s experiment->can grasp gist of a scene with 67ms
How can we recognize gist of scene so fast?
Global image features
Degree of naturalness->forest VS street
Degree of openness->more or less objects (ocean VS forest)
Degree of roughness
Degree of expansion-> convergence of parallel lines
Color
Theory of unconscious inference
Likelihood principle->perceive the object that is most likely to have caused the pattern of stimuli we have received
unconscious inferences->predictions
Bayesian inference
Prior probability + likelihood = conclusion
Review parts of brain responsible for object/scene perception
Lateral Occipital complex (LOC)->presence of objects
Fusiform face area
Extrastriate body area (EBA)
Amygdala->familiarity
Frontal lobe->attractiveness
Superior temporal sulcus (STS)->gaze, mouth, movements
Parahippocampal place area (PPA)->scenes, places
What are the three types of illusory motions?
Apparent motion->no actual motion (billboard)
Induced movement->motion of big object causes a stationary to appear to move
Motion aftereffects->waterfall illusion
–>same part of brain activated by real and apparent motions
Ecological approach to motion perception
motion is perceived when one part of the visual scene moves relative to the rest of scene in optic array
->no movement when entire field moves or remains stationary (global optic flow)
Corollary discharge theory
image displacement signal (when image moves on retina) and corollary discharge signal (eye movements)
–>movement if receive only one signal
Explain Richard detector
two neurons
delay unit
create neurons responding to movement in a specific direction
WHat are the two types of achromatopsia?
Cerebral (color blindness)->damage to cortex
Congenital (color deficiency)->absence of cone receptors
What are the two ways to mix colours?
Mixing paints->subtractive color mixture
Mixing light->additive color mixture
What are the three dimensions of colors?
Hues(colour), Saturation (intensity) and value (black to white)
Young-Helmholtz theory
Trichomacy of color vision
Color vision based on three different receptor mechanisms (color-matching tasks)
What are the three types of color blindness?
Monochromatism->shades of gray, only rods
Dichromacy->two types of pigments
-pronatopia (L wavelength)
-deuteranopia (M wavelength)
-tritanopia (S wavelength)
–>more frequent on men
anamalous trichromastism->mix wavelength differently
Opponent-process theory
pairs of colors with opposites responses
Four pures colors (red, yellow, green and blue)
Hue cancellation experiments
What are the three main aspects of sound?
Frequency->pitch
Amplitude->loudness
timbre->complexity of harmonics
effect of missing fundamental
the pitch stays the same even if remove fundamental
Describe the organ of corti
inner and outer hair cells with their stereocilia and strech tip links
between basilar and tectorial membrane
phase locking
auditory nerve fibers fire in synchrony with the rising and falling pressure of the pure tone
neural frequency tuning curves
threshold for specific frequencies measured at single neurons
–>most sensitive frequency=characteristic frequency
What are the two theories about how pitch is perceived on the cochlea?
Place coding->depending on place along the basilar membrane that is activated
Temporal coding->
What is the pathway between the cochlea and the cortex?
Cochlear nucleus->superior olivary nucleus->inferior colliculus->medial genicultae nucleus->primary auditory cortex
What are the three types of hearing loss?
Presbycusis->loss of hearing due to exposition to damaging noises or drugs
Noise-induced hearing loss->loud noises cause degeneration of hair cells
Hidden hearing loss->trouble understanding speech in noisy environment
Precedence effect
when short time delay between two sounds, perceive as one
What are the three dimensions of sound on the environment?
Azimuth (left to right), elevation (up and down) and distance
What are the different types of location cues for hearing?
Binaural cues (both ears)
-Interaural level difference->head shadow and difference in intensite of sounds for high frequency
-interaural time difference->low frequencies
–>help determine azimuth
Spectral cues(one ear)
-difference pattern for sound coming from difference location (pinna)
–>help determine elevation
reverberation time
time to decrease by 1/1000th of original pressure
What are the simultaneous and sequential grouping?
Simultaneous grouping
Location->single sound source tends to come from one location and to move continuously
Onset synchrony->If two sounds start at slightly different times, it is likely that they came from different sources
Timbre and pitch->Sounds that have the same timbre or pitch range are often produced by the same source
Harmonicity->when hear a harmonic series we infer that it came from a single source
Sequential grouping
Auditory stream segregation->perception of a string of sounds as belonging together
Ex: scale illusion or melodic channeling->grouping the sounds by similarity in pitch
Auditory continuity->Sound stimuli with the same frequency or smoothly changing frequencies are perceived as continuous even with when interrupted with other stimuli
Past experience->create melody schema
What are the different mechanoreceptors in dermis?
Merkel’s disks->respond to local skin indentations/fine details (Slowly adapting fiber (SA1))
Meissner’s corpuscles->very light touch (brail)/handgrip (rapidly adapting (RA1) fiber)
–>Merkel and Meissner near the surface/small cutaneous receptive fields
Free nerve endings->temperature and pain
Pacinian corpuscles->skin vibrations and fine texture (RA2 or PC )
Ruffini corpuscles-> sensitive to stretch and the kinesthetic sense of finger position and movement (SA2)
What are the two pathways for the cutaneous senses?
Medial lemniscal pathway->large fibers for proprioception and perceiving touch
Spinothalamic pathway->small fibers for temperature and pain
What are the components of haptic perception?
Sensory system, motor system, cognitive system
–>work together
What are the four main types of exploratory procedures (EPs)?
lateral motion, enclosure, pressure, contour following
What are the different types of pain?
inflammatory pain->damage to tissue or inflammation of joints or by tumor cells
Neuropathic pain->lesions to nervous system
Nociceptive pain->activation of nociceptors in skin
Gate control model of pain
Nociceptors->send excitatory signals to transmission cells opening the gate= more PAIN
Mechanoreceptors->inhibitory signals sent to transmission cells closing the gate= less PAIN
Central control->carry signals down from the cortex closing the gate
What are the top downs processes influencing pain?
Emotions (less pain when positive emotions), attention, expectation (place and nocebo)
What is the cycle of neurogenesis for olfactory and taste receptors?
Cycle of 5–7 weeks for olfactory receptors
1– 2 weeks for taste receptors
What are the four types of papillae on tongue?
Filiform, fungiform, foliate, circumvallate
What are the four pathways to the gustatory cortex?
Chorda tympani nerve from front and sides of tongue
Glossopharyngeal nerve from back of tongue
Vagus nerve from mouth and throat
Superficial petronasal nerve from soft palate
Anosmia
loss of smell
Pathway of odorants
nasal cavity->olfactory mucosa->olfactory receptor neurons->olfactory bulb->glomerulus
What are the names of the primary and secondary olfactory area?
Piriform cortex and orbitofrontal cortex
Why is olfaction related to memory?
Amygdala two synapses away from olfactory nerve
Hippocampus->tree synapses
