Perception and neuropschology Flashcards
sensation
active receiving of information
perception
interpretation of information ( meaning to contribute)
neural implementation
STEP 1:
sensory organs absorb energy
STEP 2:
energy is TRANSDUCED into a neural signal
STEP 3:
the neural signal - sent through the brain- further processing takes place
structure of eye
- outer layer
- middle layer
- inner layer
vision and light
light and the electromagnetic spectrum
wavelength and amplitude - controls brightness
outer layer
cornea (transparent/ binocular ability )
middle layer
choroid (needs nutrients )
inner layer
- vitreous humor
- iris
- pupil
- lens= accommodation- looks down to see focus and cataracts( from birth)
- retina
- rods and cones
- bipolar cells and retinal ganglion cells
- blind spot
- optic nerve
rods and cones function
- transduction
- properties of rods and cones
- rods and cones distribution
properties of rods and cones
CONES:
- colour= yes
- time= daytime
- resolution= high
RODS:
- colour=no
- time= night-time
- resolution= low
brain organization
- lobes ( four)
- cortex
- sub cortex ( inside brain)
visual pathway
- eyes-> sub cortex
- eyes= lateral geniculate nucleus ( pass information to next stage)
- sub cortex-> cortex
- later geniculate nucleus-> V1
V1
primary visual cortex = area 17 = striate cortex
Minshkin and Ungerledier (1982)
= Further cortical pathways - object/landmark discrimination
- double dissociation
- ventral stream-pattern perception (WHAT)
- dorsal stream-spatial location (WHERE)
double dissociation
damage area TE/IT ( TEMPORAL LOBE):
- performance on object task= IMPAIRED
- performance on landmark task= OK
damage area PG (PARIETAL LOBE)
- performance on object task= OK
- performance on landmark task= IMPARIED
neural properties of the visual system
information processing of visual neurons
- rods + cods= DIFFUSE LIGHT
- retinal ganglion cells= SPOTS OF LIGHT
- lateral geniculate nucleus cell= SPOTS OF LIGHT
- V1 cells- LINES OF DIFFERENT ORIENTATIONS
- beyond V1= ventral visual system
- beyond V1= area TE/IT
- grandmother cells
retiontopic mapping
point to point mapping of external world onto retina, lateral geniculate nucleus and V1
- V1 before= Retinotopic mapping’
- V1 after= no retinotopic mapping
lateral inhibition and receptive fields
receptive filed= area of the retina which when stimulated by light causes a change in the neural activity of the cell
- ganglion cell = DOTS
- centre surrounded architecture
what is the point of centre- surround architecture
- enhances contrast
- brightness contrast
Herman Grid illusion
-why do we see black spots-> intersections
= retinal ganglion cells performing lateral inhibition
- what information does the RGC assembly send forth if:
= bathed in diffuse light/darkness
=presented with a light/dark dot
=streets and intersections `
blindness
- right monocular blindness
- bitemproal homianpoia
- left homonymous haemianopia
- left homonymous haemianopia ( with muscular sparring)
blind sight
patient DB (damages V1) cant localize objects that he swear he cant see
Achromatopsia
absence of colour vision
-damage to V4(adds colour to image)
Akinetopsia
absence of motion vision
-damage to V5 (MT)
