Psy 121
Fall, 2007
Study guide for Chapts 4 & 5, lectures of 9/72, Oct 2&4, labs of Oct 4/5
Required reading notes: In Chapt 4 of GRG, you may skip the section on Hearing, pp. 129136 and in Chapt 5, you may skip the section on Other Modalities, pp. 187-188. There will
be frequent references to materials in Chapt 3, and you should also look at the section on
Consciousness in Chapter 8, pp. 303-308.
From Input to Output
Organization of psychological and neural processing
sensory neurons, motor neurons and the great in-between
reflexes
feedback and feedforward circuits
example of feedforward: compensation for eye movements (GRG pp 162-163)
parallel processing and the binding problem
“bottom-up” and “top-down”
the importance of attention
General Properties of Sensory Systems
empiricists, nativists
distal stimulus, proximal stimulus
dimensions of perception:
detection (absolute threshold)
signal detection theory
hits, misses, false alarms, correct negatives
sensitivity, response bias
discrimination (difference threshold)
Weber fraction
generalizations (perceptual constancies)
perceptual distortions (illusions)
dimensions of sensation:
stimulus quantity (intensity)
stimulus quality
sensory modalities
within-modality dimensions, for example:
features such as color (vision), timbre (audition), sweet/sour (taste)
spatial localization
temporal properties
neural coding of sensation:
transduction
stimulus intensity:
number of different neurons firing (recruitment)
frequency of firing of individual neurons
Psy 121, Study Guide for lectures and reading on vision (cont.)
2
stimulus quality:
which neurons fire (neuronal specificity), for example:
modality specific neurons
topographic (spatially organized) projections
pattern theory
temporal properties: phasic/tonic responses
synchrony among neurons
Vision
properties of light: corresponding psychological dimension
intensity: brightness
wavelength(s): hue and saturation
spatial origin: spatial location
receptive fields of single neurons
what are they (GRG p.180)
how are they "mapped"? (GRG Fig 4.31)
the visual system (GRG Fig 5.41)
structure of the eye (GRG Fig 4.12)
the retina (structure of retinal microcircuits, GRG Fig 4.13)
optic nerves, optic chiasm, optic tracts
lateralization in the visual system
thalamic relay: the lateral geniculate nucleus (LGN)
visual cortex
primary visual cortex (V1)
further processing areas
dorsal and ventral pathways, parallel processing (GRG Fig 5.42)
processing in the retina
photoreceptors: rods and cones (duplex theory of vision: ways in which rods & cones differ)
chemical transduction: photopigments (visual pigments)
rhodopsin in rods
3 cone opsins (trichromatic color vision, primary colors)
spectral sensitivity curves
peripheral vs foveal vision
horizontal cells: lateral inhibition (GRG Fig 4.20)
ganglion cells (GRG p. 180)
P-cells (parvo cells): center-surround receptive fields (GRG Fig 4.32)
spatial discrimination
color opponency (opponent process color vision, complementary colors)
GRG Fig 4.28
M-cells (magno cells): movement sensitivity
Important point in lecture: an analysis of neuronal specificity and pattern theory in the retina
perceptual phenomena (retinal)
absolute (detection) thresholds
Psy 121, Study Guide for lectures and reading on vision (cont.)
3
the rhodopsin spectral sensitivity curve
the cone spectral sensitivity curves (GRG Fig 4.24)
brightness contrast (e.g., GRG Figs 4.16 - 4.19) and lateral inhibition
negative color afterimage (GRG Fig 4.26): adaptation and color opponency
simultaneous color contrast: color opponency and lateral inhibition (GRG Fig 4.25)
II. processing in primary visual cortex (area V1, striate cortex)
retinotopic projection (spatial selectivity)
“feature detectors”
orientation selectivity (GRG Fig 4.23)
movement sensitivity: directional selectivity (GRG p. 161)
binocular receptive fields (basis of binocular disparity sensitivity, GRG p.157)
spectral sensitivity
cortical columns (modules)
neuropsychology: blindsight (GRG p. 305)
III. beyond V1, the "ventral stream": form detection and color processing (the "what"
system)
area V4: color
inferior temporal cortex:
“geon” detectors, object detectors
e.g., face cells in the FFA (note fMRI findings in GRG pp. 306-307)
“grandmother cells” and the binding problem
neural synchrony, gamma band oscillations
form/object recognition
"feature nets" and simultaneous multiple constraint satisfaction (GRG pp. 176-178)
priming effects (GRG p. 177)
visual segregation or perceptual parsing
grouping principles (laws of perceptual organization): proximity, similarity,
good continuation, closure, coherent motion
figure/ground
higher-order invariants
unconscious inference
perceptual phenomena
perceptual constancies
brightness constancy
size constancy
shape constancies
position constancy
illusions
subjective contours (GRG Fig 5.19)
geometrical illusions (e.g., Muller-Lyer illusion)
moon illusion
Ponzo illusion (GRG Fig 5.35)
ambiguous figures (GRG Figs 5.28 – 5.30)
impossible figures (GRG Fig 5.44)
Psy 121, Study Guide for lectures and reading on vision (cont.)
4
neuropsychology (Chapt 3): agnosias
IV. Beyond V1, the "dorsal stream": motion processing, depth perception (the "where" or
"how" system)
the parietal cortex
area V5 (MT): motion detection
Newsome’s microstimulation experiments
spatial frames of reference
perceptual phenomena
motion aftereffects (adaptation)
apparent (or stroboscopic) movement (GRG Fig 5.10)
induced motion (GRG Fig 5.12)
depth cues (GRG pp. 157-163)
binocular disparity (retinal disparity)
pictorial cues (monocular depth cues)
linear perspective, relative size, interposition, texture gradients
light & shadow
motion parallax, optic flow
neuropsychology: neglect syndrome (Chapter 3)
visual attention
involuntary (reflexive, exogenous) and voluntary (endogenous) orienting
visual search
feature-driven pop out
serial search for feature conjunctions
illusory conjunctions
attention and perceptual organization: ambiguous figures