Perception Flashcards
what is akinetopsia - case study LM
unable to perceive motion
very specific of brain is damaged, MT or V5 - prcesses visual motion
what are rods like
sensitive in low light
lower acuity
colour blind
periphery of the retina
what are cones like
need more light
higher acuity
colour sensitive
in the fovea
are there any cones or rods on the blind spot
no
is where the optive nerve is
explain the cells in the eye that transduce light to vision and begin relay to the brain
photoreceptors (cones and rods)
bipolar cells next
ganglion cells to the optic nerve
what brain areas recieve inputs from the optic nerve
in the thalamus - laternal geniculate nucleus
in the cortex
V1 - primary visual projection area/ primary visual cortex in the occipital lobe
explain what areas of the brain see what
both eyes process both sides of the world
left visual cortex “sees” the right of the visual field and vice versa for the right
what is lateral inhibition
occurs in cells in the retina
each active cell inhibits its neighbours
this emphasizes the edges of stimuli
so strips of gradually getting lighter shades of black
which side of the bar appear darkest
the one next to the darker colour as patterns of lateral inhibition between neighbouring cells on the retina lead to that edge being enhanced and so appearing darker
where do we place a single cell recording and what can we define about cision from it
electrode placed just outside a neuron in the animals optic nerve or brain
used to define the cells receptive field
what is the receptive field
the size and shape of the area in the visual world to which that cell responds
what did Hubel and Weisel discover
specialized neurons in the brain with distinct receptive fields
eg centre surround cells - stimulus in centre = higher firing, stimulus in surrund = lower firing
what do edge detectors do
receptive to lines of particular orientation
-horizontal and vertical are the most common
explain parallel processing
divide and conquer
different cells process different areas of the visual world and different brian areas process this all simultaneously
explain the role of the “what system” in parallel visual processing
identification of objects
occipital-temporal pathway
explain the role of the “where system” in parallel visual processing
locations of objects and guiding our responses
occipital-parietal pathway
what happens when occipital-temporal pathway is damaged
visual agnosia
can describe object when shown it but cannot tell you what it is
dissconnection between object and recognition
what happens when the occipital-parietal pathway is damaged
problems with reaching for seen objects
what do parvocellular cells do
specialized for spatial analysis and detailed from
what do magnocellular cells do
specialization for motion analysis and depth perception
what is the binding problem
parallel processing splits up processing of our world
but we do not see the world as disjointed
explain three things that help us solve the binding problem
spatial positioning - reassembling of pieces of references position
neural synchrony - rythm of neurons that are firing in response to the same item tend to be in sync
attention is crucial for the binding of visual features - when attention is overloaded people make conjunction errors
simply no definte answers yet but this is some evidence
explain conjunction errors
seeing a blue H and red T but reporting a red H
define sensation
absorbing raw energy through our sensory organs