Intro to Cognitive Psyc

• Prefrontal Cortex


  • Involved in personality expression, decision making (executive functioning), moderating social behaviour (inhibiting and allowing behaviour), choosing between "right" and "wrong" (conscience), long-term planning
• Brain regions we are building

  • Hippocampus
  • Amygdala
  • Prefrontal Cortex
  • Broca's Area (language production)
  • Wernicke's Area (language comprehension)
  • Arcuate Fasciculus (large bundle of nerves)
• Arcuate Fasciculus


  Large bundle of nerves (Latin for Curved Bundle)
• Akinetopsia


  Motion blindness, seeing the world in "still shots" (stroboscopic)
• V5/MT


  Visual area responsible for the perception of motion, damaged in Ms. Leibold causing Akinetopsia
• The Visual System


  • Parallel Processing - a series of neurons communicate information from the retina to the cortex
• Visual Processing


  1. Photoreceptors (rods and cones) on the retina

  2. Bipolar cells transmit signals

  3. Ganglion cells (optic nerve)
• Fovea


  Concentration of cones
• Visual Processing


  Bipolar cells transmit signals to Ganglion Cells (Optic Nerve)
• Contralateral & Ipsilateral Paths

  Paths of visual information from the eyes to the brain
• Lateral Geniculate Nucleus


  Inside the Thalamus, contains Parvocellular Cells (size, color, shape/form analysis, critical for faces) and Magnocellular Cells (motion and depth, guides directed movement)
• Parvocellular Cells


  • Begin processing "what"
• Magnocellular Cells


  • Begin processing "where"
• Primary Visual Cortex (V1)

  Also called the Striate Cortex, at the very back of the occipital lobe, highly specialized for processing information about static and moving objects, excellent at pattern recognition/differentiation
• Dorsal (Where) Stream


  Location of objects and guiding of our responses/movements (e.g. reaching, picking up a glass, catching a ball), Occipital-parietal pathway (up to the Sensory Cortex & Motor Cortex)
• Ventral (What) Stream


  Identification of objects and faces, Occipital-temporal pathway (connects to Limbic System – contains the Hippocampus and the Amygdala)
• Visual Agnosias


  Caused by disruptions to the What pathway, including Prosopagnosia (inability to recognize faces) and Visual Agnosia (inability to recognize objects)
• Capgras Delusion


  No connection of face to emotion center, visual recognition without emotional recognition
• Associative agnosia


  Can see the object but cannot describe it from sight, nor name it, do not know what it is. Cannot connect to previous knowledge.
• Lateral Inhibition


  In the ganglion cells (Optic Nerve), some excited cells can inhibit the excitement (firing rate) of their neighbors on one or both sides, decreasing their neighbors firing rates
• Apperceptive agnosia


  Can only see an objects shapes, colors and position (features) but cannot see them together. i.e. Cannot see intact objects. They cannot look at an object and draw it. They can draw well from memory
• Less intense stimuli (darker areas)


  Result in less lateral inhibition, edge looking darker against a lighter edge
• Bottom-up (or data-driven) processing

  Stimulus-driven effects. Features of objects - lines, curves etc. From parts to the whole.
• Lateral Inhibition


  • Helps define an object's shape through edge enhancement - the lighter edge appears brighter and the darker edge beside it appears even darker due to contrast
• Top-down (or concept-driven) processing

  Knowledge- or expectation-driven effects. Knowing what something "should" be - based on previous knowledge and inference. From what the expected whole is down to its individual parts (features).
• Center-surround Cells


  Aka Dot Detectors
• Features


  Building blocks. Things various objects have in common. Play a role in visual search
• Edge Detectors


  Cells that show preferential firing for certain edge orientations (horizontal to vertical)
• Integrative agnosia


  Symptoms of both apperceptive and associative agnosia. Impaired in seeing objects as wholes - cannot judge how the features are bound together. This suggests that we perceive things in parts - features that we then bind together somehow.
• Visual Cells


  • Some cells fire maximally at certain sized angles
  • Some fire maximally in response to corners or notches
  • Some cells fire in response to specific types of movement (e.g. left to right, vertical from up to down)
• Parallel processing splits up visual processing, but we do not see the world as disjointed - this is the binding problem
• Tachistoscope


  A word or a list of words is presented to the participant for a controlled brief amount of time (20 - 40 milliseconds) each. Between each presentation of a word, a mask is presented. The mask, a collection of letters, is intended to disrupt rehearsing the word - prevents any continued processing. Then they are asked if they saw certain words. Recognition
• Elements that help solve the binding problem

  • Spatial position - each processing location has a map based on where everything is in the visual field
  • Neural synchrony - the brain keeps track of when the various neurons fire in the different brain areas to establish a pattern of what features go with what
• Repetition priming


  Words that have appeared recently to the participant are more easily recognized.
• Attention is critical for binding visual features together, when attention is overloaded people will make conjunction errors - errors in binding
• Conjunction Error


  An error in binding visual features together
• Word-superiority effect


  People's response when asked whether "DARK" had an "E" or a "K" is fastest. Also faster than when a letter is presented within a nonsense letter string such as "JPHKW."
• 3 systems that govern attention

  • Orienting System
  • Alerting System
  • Executive System
• Degree of Well-Formedness


  How statistically likely it is for a specific letter combination to occur. E.g - THE is extremely likely to occur & always primed.
• Orienting System


  • Responsible for disengaging attention, shifting it, and reengaging on a new target