“What” and “Where” Pathways in the Brain – A Hypothesis About Localization of Perceptual Functions Psychology 355: Cognitive Psychology Instructor: John Miyamoto 04/03/2018: Lecture 02-2 Note: This Powerpoint presentation may contain macros that I wrote to help me create the slides. The macros aren’t needed to view the slides. You can disable or delete the macros without any change to the presentation.

Outline Brain anatomy “What” and “Where” Pathways Double dissociations Close connection between perception and action Psych 355,, Miyamoto, Spr '18 Diagram of Lobes of the Brain

Lobes of the Left Hemisphere Head is facing LEFT 3 Psych 355, Section, Spr '18 Terminology for Different Orientation in Brain Anatomy

Terminology for Different Orientation in Brain Anatomy Superior Dorsal Head is facing LEFT The orientation nomenclature is important as it provides the anatomical basis for the ‘ventral’ and ‘dorsal’ pathway. "dorsal" derives from the Latin for back. "ventral" derives from Latin for belly or stomach. "rostral" derives from Latin for beak. "caudal" derives from Latin for tail. Anterior Posterior Rostral Caudal Inferior Ventral Psych 355, Miyamoto, Spr '18 Summary of Terminology

Summary of Terms for Orientations in Brain Anatomy TOP: "superior" or "dorsal": "dorsal" derives from the Latin for back. BOTTOM: "inferior" or "ventral" "ventral" derives from Latin for belly or stomach. FRONT: "anterior" or "rostral" "rostral" derives from Latin for beak. BACK: "posterior" or "caudal" "caudal" derives from Latin for tail. Psych 355,, Miyamoto, Spr '18 Diagram Showing the "What" and "Where" Pathways in Brain Anatomy

"What" versus "Where" Pathways in Monkey & Human Brains "Where" Visual Pathway "Where" pathway is more activated by spatial tasks. A.k.a. the dorsal pathway. "What" pathway more activated by tasks that require processing of object properties. A.k.a. the ventral pathway. Human "What" Visual Pathway Monkey Figure 3.33, Goldstein Psych 355, Miyamoto, Spr '18 "What" Task in Monkey

"What" Task with Monkeys (Object Discrimination) Monkey is shown an exemplar: Now monkey has to pick the matching object: If monkey pushes aside the matching object, he finds food hidden under it. The “what” task requires attention to object properties, color and shape. Psych 355, Miyamoto, Spr '18 "Where" Task

"Where" Task with Monkeys (Landmark Discrimination) Monkey is taught that the reward will be next to the landmark: Next the monkey sees two potential hiding places for the reward. The reward is hidden under the block that is next to the landmark. Double Dissociation Btwn "What" & "Where" Tasks in Monkeys Psych 355, Miyamoto, Spr '18

Double Dissociation Between "What" & "Where" Pathways Figure 3.32, Goldstein Surgical removal of part of temporal lobe makes object discrimination difficult; landmark discrimination not impaired. Start Discussion of Double Dissociation Psych 355, Miyamoto, Spr '18

Double Dissociation Between "What" & "Where" Pathways Figure 3.32, Goldstein Surgical removal of part of temporal lobe makes object discrimination difficult; landmark discrimination not impaired. Surgical removal of part of parietal lobe makes landmark discrimination difficult; object discrimination is not impaired. Start Discussion of Double Dissociation Psych 355, Miyamoto, Spr '18

Double Dissociation Between "What" & "Where" Pathways Figure 3.32, Goldstein Surgical removal of part of temporal lobe makes object discrimination difficult; landmark discrimination not impaired. Surgical removal of part of parietal lobe makes landmark discrimination difficult; object discrimination is not impaired. Double dissociation! "What" and "Where" Dissociations in Human Studies Psych 355, Miyamoto, Spr '18

"What" & "Where" Pathways: Double Dissociation in Human Patients "Where" Visual Pathway Patient with bilateral parietal- occipital damage: Patient could not describe locations of familiar places but could describe the appearance of objects. Patient with bilateral inferior temporal damage: Patient could not describe appearance of objects, but could describe locations. "What" Visual Pathway Appearance question: What does your toothbrush look like? Location question: Where is your toothbrush? Psych 355, Miyamoto, Spr '18 Alice vs Bert – Double Dissociation Btwn Naming & Reaching

Another Example of Double Dissociation of "What" & "Where" Pathways: Appearance question: What does your toothbrush look like? Location question: Where is your toothbrush? damage to temporal lobe damage to parietal lobe Psych 355, Miyamoto, Spr '18 Orientation Task – Another Double Dissociation Example

Orientation Matching Task Patient D.F. has damage to temporal lobe due to carbon monoxide poisoning. Patient D.F. must turn the card to match the orientation of the slot. (The results are recorded so that perfect accuracy is indicated by a vertical line.) D.F. does very poorly on orientation matching when compared to normal controls. D.F.'s performance. Pretty bad. Normal Controls Psych 355, Miyamoto, Spr '18 Mailing Task

Mailing Task (Requires Perception & Action) Patient D.F. must put the card through the slot. D.F. does almost as well as normal controls. Mailing Task: Put the letter through the slot. D.F.'s performance. Pretty good Normal Controls Psych 355, Miyamoto, Spr '18 Comparison Btwn Orientation & Mailing Tasks

Orientation Matching Task Mailing Task Orientation Matching Task – Primarily perception Mailing Task – Coordinate perception with action This is a single dissociation. Mechanisms for the task are different but they may not be independent. Psych 355, Miyamoto, Spr '18 “What” Pathway = Perception Pathway; “Where” Pathway = Action Pathway?

Orientation Matching Task Mailing Task Hypothesis: "What" Pathway = Perception Pathway "Where" Pathway = Action Pathway Summary - END Psych 355, Miyamoto, Spr '18

Summary Double dissociations are a useful tool for investigating localization of function. Hypothesis: "What" Pathway = Perception Pathway "Where" Pathway = Action Pathway (or maybe just more linked to action) END - Or Continue to Class Experiment Psych 355, Miyamoto, Spr '18

Class Experiment: Demonstration of Top Down Processing Instructor: Divide the classroom into a “left group” and “right group”. I will show you an image. Briefly write down a label for what you see. E.g., if you see a chair, write down “chair.” Left half of the room will close their eyes for the first image. Right half of the room will close their eyes for the second image. Everyone will open their eyes and complete the experiment. Condition 1: View Image 1a Psych 355, Miyamoto, Spr '18

Students on Left – Eyes Open Students on Right – Eyes Closed Label this image “Image 1a”. Write down a name for what you see. Condition 2: View Image 1b Psych 355, Miyamoto, Spr '18

Students on Left – Eyes Closed Students on Right – Eyes Open Label this image “Image 1b”. Write down a name for what you see. View Image 2 Psych 355, Miyamoto, Spr '18

Label this image “Image 2”. Write down a name for what you see. Everybody’s Eyes Open Label this image “Image 2”. Write down a name for what you see. Collect Results of Class Demo Experiment Psych 355, Miyamoto, Spr '18

Results of Classroom Experiment We will only collect data for what you saw in Image 2. People on the LEFT SIDE: Raise your right arm if you wrote down “mouse” or “rat” for Image 2? Raise your left arm if you wrote down “old man” or “man” or “face” for Image 2? People on the RIGHT SIDE: Show Images 1a, 1b, 2 Psych 355, Miyamoto, Spr '18

LEFT SIDE saw Image 1a RIGHT SIDE saw Image 1b EVERYONE saw Image 2 . Top Down Processing: What you see in Image 2 is influence by what you expect from Image 1. EVERYONE saw Image 2 . Results of Classroom Experiment Psych 355, Miyamoto, Spr '18

Results of the Classroomn Experiment Left side of the room saw Image 1a only. Categorization of Image 2 by left side of the room: 29 saw “mouse” 0 saw “old man” Right side of the room saw Image 1b only. Categorization of Image 2 by right side of the room: 17 saw “mouse” 13 saw “old man” Image 1a Image 2 Image 1b Results exhibit influence of top- down processing: Prior exposure to mouse-like or man-like image influences interpretation of second image. Psych 355,, Miyamoto, Spr '18 Tomorrow’s Topics - END

Tomorrow’s Class More discussion of top-down and bottom-up processes. Perceptual features Gestalt principles of perception Psych 355,, Miyamoto, Spr '18 END