1. Basic Brain Principles and Attention/Perception
PSYC560
Cognition and Affective Processes

2. Getting Neurotic
Neurons: cells specialized to receive and transmit information in the nervous system
Cell body: contains mechanisms to keep cell alive
Axon: tube filled with fluid which transmits electrical signal to other neurons
Dendrites: (so named because of it’s resemblance to tree branches) multiple branches reaching from the cell body which receives information from other neurons
Sensory receptors: specialized to respond to information received from the senses

4. This is Prettier

5. Basic, Basic Terms
Transduction: receptors transform energy from environment into electrical energy
Action potential
Neuron receives signal from environment
Information travels down the axon of that neuron to the dendrites of another neuron

7. Size Doesn’t Matter: Rate Does!

8. Neural Communication Synapse: space between axon and dendrite
When the action potential reaches the end of the axon, synaptic vesicles open and release neurotransmitters which are picked up by the receiving dendrites
Neurotransmitters: chemicals that affect the electrical signal of the receiving neuron
Excitatory: increases chance neuron will fire
Inhibitory: decreases chance neuron will fire

10. Who’s Your Grandma?
Feature detectors: neurons that response best to a specific stimulus
Hubel & Wiesel (1965)
Simple cells: neurons that respond best to bars of light of a particular orientation
Complex cells: neurons that respond best to an oriented bar of light with a specific length
Neural code: information contained in the neural firing to any object/experience
Specificity coding: representation of a specific stimulus by firing of specifically tuned neurons specialized to just respond to a specific stimulus
Grandmother cell

11. Cat Sees Spot

12. Grandma Loves Controversy
Too many different faces/objects to assign specific neurons to each one
Even though neurons may respond only to specific types of stimuli, they still respond to a number of different types of that stimuli type
Quiroga and coworkers (2005)
Epilepsy patients viewed pictures of specific individuals/objects while hippocampal neuron firing was recorded
Some neurons fired for just one person/object
Distributed coding indicates a specific stimulus is distributed across a number of neurons

13. This is Your Brain: Some Gross Anatomy
Cerebral cortex contains mechanisms responsible for most of our higher mental functions
Temporal lobe: language, memory, hearing, perceiving forms
Occipital lobe: vision
Parietal lobe: touch, vision, attention
Frontal lobe: language, thought, memory, motor functioning

14. More Gross Stuff
The hippocampus and laying down new memories (the famous freak fencing faux pas)
Amygdala: The emotional almond (engaged in emotionally laden memories)

15. Perception: Bottoms Up!
Bottom-up processing
Energy registers on receptors
Incoming data
Top-down processing
Person’s knowledge, experience, expectations

17. What’s in an A? Template-matching Interactive activation model
When pattern matches template, perceiver recognizing letter
Problem: many different templates would be needed to recognize just one letter
Interactive activation model
Feature level
Letter level
Word level

18. A “K” By Any Other Shape… Doesn’t Match the Template!

19. The Latest Word Recognizing a single letter Recognizing a word
Feature units activated
Activation sent to each letter unit containing features activated
Letter unit activated most indicates letter
Recognizing a word
Letter unit for each letter’s position in a word
Letter units send activation to all words containing letters in correct positions
Word superiority effect
Letters easier to recognize when in a word
Less easy to recognize letters in a non-word or presented alone

21. Palmer (1975) in the Kitchen
First, shown target image (kitchen)
Then “flashed” probes
Mailbox ID’ed as loaf of bread
Drum ID’ed as jar lid
The moral of the story is context plays a major role in our largely reconstructive memories

23. Now Something Slightly Different
Max Wertheimer bored at the train station in 1933
Let’s turn out the lights for this one…

24. Gestalt Laws of Organization
Proximity
Similarity
Continuity
Closure
Orientation (“common fate” if in motion)
Figure Ground
Pragnanz (“Good Figure”)

25. Continuity
Also typifies Pragnanz

26. Similarity
Do we do this socially as well?

27. Proximity
Ever assume people that are close together in space are somehow “together” in other ways?

28. Orientation

29. Figure Ground

30. Combining Figure Ground and Closure
Do you see subjective contours?

31. How About Now?

32. Lateral Inhibition
As the neurons in your retina fire “on,” it shuts off nearby retinal neurons.
This allows us to detect edges
This also presents a few perceptual anomalies, such as….

33. Phantom Shapes and Colors

34. Illusory Movement

35. Getting Seasick Yet?

36. 3D Perception Monocular Cues Relative Size Occlusion
Linear Perspective
Shadowing
Texture Gradient
Motion Parallax

37. Occlusion and Relative Size

38. Linear Perspective

39. Shadowing
Home experiment with Halloween masks

40. Texture Gradient

41. Motion Parallax
Used frequently by cats preparing to pounce

42. Binocular Cues Accommodation (lens contraction)
Convergence (ocular muscle contraction)
Binocular disparity
Stereoscopes (View Master)
Parallax viewers
3D movies

43. The Amazing Color Change

44. Attention!

45. Did Someone Say My Name? The cocktail party phenomenon Early Selection
Filter on the basis of physical characteristics
Bottom up
Late Selection
Filter on the basis of meaning (all data is processed, then filtered)
Top down

46. Sensorimotor Gating
Filtration of non-relevant information in favor of important stimuli
Often on the basis of environmental cues
Prepulse Inhibition
Disrupted by stimulants
Commonly disrupted in individuals with schizophrenia (schizophrenia as an attention disorder?)

47. Perceptual Disorders: Blindsight
Damage to striate cortex
Often report seeing a small area of light and blind throughout most of the visual field
Will react to and report details of objects in the visual field, though report no conscious sensation of seeing them
Perception appears disrupted, but not processing

48. Perceptual Disorders: Agnosias
Apperceptive Agnosia
Form perception is damaged
Cannot draw familiar objects
Cannot describe objects
Cannot match similar objects
Associative agnosia
Damage at a later “stage”
Can draw, match, and descibe objects
Cannot recognize them
Cannot associate representative images with stored information
Prosopagnosia
Cannot recognize faces (even own reflection)

49. Questions? Thoughts?