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50 Cards in this Set
- Front
- Back
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Platonic view of vision and the world?
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The 'real world' exists but mortal sense are only capable of sampling a small fraction of it.
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Friedrich Nietzsche's view of vision and the world?
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There is no real world, only the world inside your head. Vision as construction.
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The world that we visually sense is entirely dependent upon...
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- our individual perceptions
- light |
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Excitation refers to...
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a state/response due to external stimuli, an application of energy.
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Sensation refers to...
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the detection of external stimuli by sensory organs.
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At what stage in the visual pathway is an action potential first generated?
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Ganglion cells
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What do L, M & S denote when applied to cones?
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Long (red), Medium (green) & Short (blue) wavelengths of light.
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Why are photoreceptors anchored to the retina despite there being neural matter between between the light source and receptor?
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Inverted retinal neural design, reason for blind-spot.
Protection and insulation of photoreceptors. Transportation of nutrients. |
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A colour space is...
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an abstract model/representation of colour in space.
e.g. RGB & CYMK |
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Orthogonality in the vector representation of signal-coding confers which of the following properties upon that stage of the system?
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- Orthogonality allows overlapping stimulus-coding.
- Positive and negative interactions |
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Which statement best describes a receptive field?
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Receptive fields are an abstract construction describing the sensitivity of a sensory neuron.
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What is the most likely format of the first spatially structured (or differentiated) receptive fields in the visual system?
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Centre - Surround organisation. Donut shape.
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The receptive field arrangement referred to in Question 12 confers what properties to the system?
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The property of opponency.
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The term "opponency" refers to...
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Theory of opponency records the differences/opposites between colour or stimuli.
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Why, when considering the processing of the neural signal, is the actual physical location of any visual neurone other than the photoreceptors, arbitrary?
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Information from the receptive fields relate to the same x,y,t space and photoreceptors are the only thing in direct contact with the stimuli. It doesn't matter after that point.
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Why, however, is the relative location of any sensory neurone potentially important?
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Information (shapes, lines and contours) in the real world has to be represented the same way in the brain.
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What is meant by the term "retinotopic mapping"?
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Retinotopic map is the topopgraphic map of the retina as represented in the brain. It maintains relative relationship of neurons whilst the actual location is irrelevelant/arbitrary as long as they are in close proximity. (Visual cortex)
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What is meant by the term "tonotopic mapping"?
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Tonotopic map is the topographic map of the audio input from the cochlea represented in the primary audio cortex of the brain.
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The term "phase-coherence" refers to the hypothesis that...
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an edge/border is signalled consistently across all scales of analysis.
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The idea of modularity in visual processing refers to...
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different modules in the brain have differentiated functions.
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What reason may you have for questioning the assumption that the LGN is just a relay station fo signals travelling from the retina to the cortex?
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There are more neural pathways from the visual cortex to the LGN than from the LGN to the visual cortex.
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Taken as a population, primary visual cortical (v1) neurones have what critical property?
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V1 cortex (striate) are responsible for representing everything in the raw form. All visual information enters at this point.
- Cortical magnification - Orientation sensitivity |
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An example of context-dependency in vision is...
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Matchsticks arranged in circles.
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What is red?
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Red is definitive as a specific wavelength but sensation and perception of it differs between individuals.
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An attentionally-controlled motion system may...
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Attention modulated motion is the isolation of a particular aspect of motion so that we are not overwhelm by input of information.
e.g. Keeping the world still as you move your eyes. |
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The visual system appears to dissociate motion-signals elicited by eye-movements or from the retinal motion by...
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the In-Flow Hypothesis: feedback from the eye-movement.
the Out-Flow Hypothesis: feedback from the commanding signal. |
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The spatial structure of natural textures is consistent with the properties of the system because...
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Receptive fields are more selective to natural textures due to evolution???
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"Adaptation" refers to...
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reduced sensitivitity to the stimulus as a result of repeated exposure.
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What is meant by the term "parallel processing"?
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It is the ability of the brain to process information simultaneously.
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A form of parallel processing in the auditory system is implemented in the cochlea nucleus by...
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Divergence of auditory signals received from the cochlea before its input into the auditory cortex.
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One critical similarity between the auditory system and visual system is...
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Inputs are both topographically mapped out onto the brain in their respective cortexes.
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One critical difference between the auditory system and visual system is...
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Visual information is processed contra-laterally whilst auditory information is processed bilaterally.
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The terms M and P in the context of the visual system refer to...
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two types of LGN cells: Magnocellular (input from Parasol Ganglion cells) and Parvocellular (input from Midget Ganglion cells). Oh the irony.
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Information is...
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What stimuli is translated into for the brain to process.
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A vector is...
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Direction + Magnitude. A single directional signal.
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The theoretical hierarchy established by David Marr is...
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Problem -> Algorithm -> Implementation
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"Retino-cortical expansion" refers to...
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Cortical expansion. Where there is a larger number of neurones corresponding to the centre of the visual field compared to the peripheral.
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Which of the two structures listed below exploit orthogonality in the representation or operation?
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semicircular canals? Orientation receptive fields in V1 cortex.
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What computational role does the cochlea play in audition other than simply transduce the auditory signal?
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It also has a function in the vestibular system, spatial awareness.
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Psychophysics is...
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The relationship between a physical stimuli and the sensation and perception they affect.
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What aspect of the relationship between the stimulus and the cortical representation is different between vision and audition?
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The visual system exhibits some form of cortical magnification whereas the auditory system does now. (Varies a bit but relatively constant)
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The two most likely kinds of motion detector in the human visual system are called...
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- Delay&Compare/Correspondence/Hassenstein-Reichardt/Fly&Beetle Detector
- Spatiotemporal Gradient Detector |
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The three critical dimensions of vision are...
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X axis, Y axis and time. (x,y,t)
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The term "Biological motion" describes...
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Movement made by biologically active stimuli. e.g. Stick figures. Dots fit our expectations and fill in gaps of biological movement.
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Interaction between V1 orientation-selective receptive fields follow what laws?
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Aligned V1 receptive cells positively interact whilst orthogonal receptive cells negatively interact.
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The visual system is sensitive to...
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The visual wavelengths of 380 - 760?
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What critical neural interaction is affected by hallucinogenic drugs?
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Affects neurotransmitter receptors, particularly serotonin. Disrupts action potentials and signalling.
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Your experience of reality is...
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Subjective and individual.
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Synaesthesia is...
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a cross wiring of different senses.
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One fish, two fish,...
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Red fish, blue fish.
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