Chapter 7: The Seeing Brain

• What is meant by Biological Motion?


  The ability to detect whether a stimulus is animate or not from movement cues alone
• What are structural descriptions?


  A memory representation of the three-dimensional structure of objects
• What is meant by Apperceptive Agnosia?


  A failure to understand the meaning of objects due to a deficit at the level of object perception
• What is meant by Associative Agnosia?


  A failure to understand the meaning of objects due to a deficit at the level of semantic memory
• what is associative agnosia? (in terms of identity and perception)


  Impaired recognition of objects despite intact visual perception.
• what is apperceptive agnosia? (in terms of identity and perception)


  Impaired recognition of objects due to a deficit in integrating sensory information with stored knowledge.
• What is meant by Figure-ground segregation?


  The process of segmenting a visual display into objects versus background surfaces
• What is Integrative Agnosia?


  Failure to/ difficulty in integrating parts into a whole in visual perception. (A kind of apperceptive agnosia?)
• What is meant by Object Constancy?


  An understanding that objects remain the same, irrespective of differences in viewing condition
• What is meant by Adaptation (or repetition suppression)?


  A reduced neural response to a stimulus, or stimulus feature, that is repeated
• What is Adaptation remind me of from B&B Tresilian's section?


  Habituation: the diminishing of an innate response to a frequently repeated stimulus.
• What is category-specificity?


  The notion that the brain represents different categories in different ways (and/or different regions)
• What are Face recognition nits (FRUs)?


  Stored knowledge of the three-dimensional structure of familiar faces
• What are person identity nodes (PINs)?????


  An abstract description of people that links together perceptual knowledge (e.g. faces) with semantic knowledge
• What is the Fusiform face area (FFA) in the brain?


  An area in the inferior temporal lobes that responds more to faces than other visual objects, and is implicated in processing facial identity
• What is meant by Prosopagnosia?


  Impairments of face processing that do not reflect difficulties in early visual analysis (also used to refer to an inability to recognize previously familiar faces)
• What is Categorical Perception?


  The tendency to perceive ambiguous or hybrid stimuli as either one thing or the other (rather than as both simultaneously or as a blend)
• Which visual illusion does the image below depict?

  WWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWW

  1. Ebbinghaus
  2. Kanizsa
  3. Thatcher
  4. Muller-Lyer


  Answer: 2) KanizsaAnswer: 2) Kanizsa
• What misconception might new students have about the role of the eyes and brain in vision?

  They might believe that the eyes do the seeing and the brain merely interprets the image on the retina.
• How does the brain contribute to vision beyond the role of the eyes?

  The brain actively constructs a visual representation of the world, not just reproducing the light pattern on the eyes.
• What does the brain do with the continuous pattern of light it receives?

  The brain divides it into discrete objects and surfaces and translates it into a three-dimensional model.
• What is the Kanizsa illusion an example of?

  It illustrates how the brain makes inferences during visual perception beyond raw information.

  
• What is the difference between sensation and perception?

  Sensation refers to the effects of a stimulus on sensory organs, while perception involves interpretation of that stimulus.
• What is the retina?

  The retina is the internal surface of the eyes that contains photoreceptors converting light into neural signals.
• What are the two types of photoreceptors in the retina?

  Rod cells, specialized for low light, and cone cells, specialized for detecting different wavelengths of light.
• Where is the highest concentration of cones found in the retina?

  At a point called the fovea.
• What is the role of bipolar cells in the retina?

  Bipolar cells detect light areas on dark backgrounds (ON) or dark areas on light backgrounds (OFF).
• What is a center-surround receptive field?

  It is a region of space that elicits a response from a neuron, responding to differences in light across the center and surround.
• How do retinal ganglion cells respond to light?

  They respond to differences in light across their receptive fields, not just to light itself.
• What is the blind spot in the eye?

  The blind spot is the point where the optic nerve leaves the eye, containing no rods or cones.
• What happens when light falls on the blind spot?

  One does not perceive a black hole in vision due to the brain filling in missing information.
• What is the primary visual cortex also known as?

  It is also referred to as V1 or the striate cortex.
• What is the geniculostriate pathway?

  It is the dominant visual pathway in the human brain that travels to the primary visual cortex via the lateral geniculate nucleus.

  
• How is information organized in the lateral geniculate nucleus?

  Information is divided according to the eye (left or right) and further subdivided into parvocellular and magnocellular layers.

  
• What do parvocellular cells respond to?

  Parvocellular cells respond to detail and are concerned with color vision.
• What do magnocellular cells respond to?

  Magnocellular cells are more sensitive to movement than color and respond to larger areas of the visual field.
• What is the role of neurons in the primary visual cortex (V1)?

  They transform information from the lateral geniculate nucleus into a basic code for visual information extraction.

  
• Who were the pioneers in studying the properties of neurons in the primary visual cortex?

  David Hubel and Torsten Wiesel.
• What did Hubel and Wiesel discover about simple cells?

  Simple cells respond to particular orientations of light.
• How do complex cells differ from simple cells?

  Complex cells have larger receptive fields and require stimulation across their entire length.