module 3 Flashcards
how do eyes tranduce light into signals that can be sent to the eye
photoreceptors, which form the retinae of human eyes. this begins a process that changes the membrane conductance of the photoreceptor causing a wave of depolarisation
primary visual cortex
Signal leaves your eye via the optic nerve travelling to the optic chiasm. Here signals cross, so information from either side of visual space travels to one side of your brain. S
hit rate
is proportion of times a participant reports seeing an input when it is actually presented.
false alarm rate
are the proportion of times a participant reports seeing an input when it wasn’t presented.
signal detection theory
allows experimenters to measure sensitivity and bias - which refers to the tendency to report if a signal has or has not been presented, regardless of whether it has been presented.
receptive field
Position on retina that images must fall upon to make that visual neuron respond
response selectivity
The type of input to which a cell will respond
akinetopsia
or the patient with motion blindness the world appears as is viewed through a strobe light.
sensation
an ability to detect sensory input.
perception
your subjective experiences of sensory input
transduction
the conversion of electromagnetic radiation into neural events. Involves light sensitive chemicals
visual pigments
Pigment absorbs photons of light, beginning a process that changes photoreceptor membrane conductance, causing depolarisation and action potentials
the physiological blind spot
- The point at which the optic nerve leaves your eye is called the optic disc
opponent process theory
fter protracted viewing of certain colours, you can see oppositely coloured afterimages
colour constancy
in different conditions the colours of the same wavelength of light can look very different
specialisation
cells respond selectively to specific stimulus characteristics
modularity
cells that respond to similar stimulus characteristics are clustered into specific brain regions
a hierarchy of processing structures
cells respond to progressively complex stimulus characteristics as we follow the anatomical connections from the retina through to higher level visual brain regions
receptive field
the region of retina to which a visual cell is responsive
simple V1 cells
Simple V1 cells are responsive to oriented stripes of contrast located in a specific subfield of its RF.
end-stopped V1 cells
End-stopped V1 cells are responsive to oriented striped of contrast of a specific (limited) length
complex V1 cells
Complex V1 cells are responsive to oriented striped of contrast located anywhere within its RF
complex direction-selective V1 cells
Complex direction-selective V1 cells are responsive to oriented stripes of contrast located anywhere within its RF that move in a particular direction
V1 response selectivity
The orientation tuning of V1 cells is possible by taking excitatory inputs from bands of LGN cells, which in turn are activated by bands of retinal ganglion cells.
Retinotopic mapping
adjacent neurons in visual brain regions encode information from adjacent regions on the retinal surfaces
blindsight
The primary visual pathway travels to primary visual cortex (V1) via the lateral geniculate nucleus (LG)…
BUT, visual information also projects from the superior colliculus (SC) to the pulvinar to the medial temporal lobe (MT or V5)…
V5 causes
akinetopsia
V4 causes
colour blindness
