Cognitive Prosem. December 1, 2008

Transcription

1 Cognitive Prosem December 1, 2008

2 Spatial Representation What does it mean to represent spatial information? What are the characteristics of human spatial representations? Reference Frames/Systems Distortions What are the neural substrates and how do they inform the preceding questions?

3 Spatial Representation McCloskey Chapter provides overview of different meanings of spatial representation Focus on: Why it is important to think about different types of spatial representations What distinguishes Spatial 1, Spatial 2, & Spatial 3 What the empirical evidence & neuropsychogy tell us about representation

4 Spatial Representation Spatial memories come from multiple modalities vision is most common information from movement through or interaction with space information from auditory cues Shelton & Yamamoto Role of vision in spatial cognition Visual coding vs. visual contributions

5 Reference Systems The concept of location is inherently relative (Mou & McNamara, 2002) To know location, we must have a reference Homewood is north of downtown. Baltimore is on the East Coast. Ames Hall is south of Remsen Hall. For any of these to be meaningful, we have to understand the spatial terminology and the reference.

6 Reference Systems Several possible reference frames for spatial memory egocentric (self-to-object) retinal coordinates body-centered coordinates environment-centered object-to-object landmark-to-object geocentric (world-centered) cardinal directions latitude/longitude

7 Reference Systems Self-to-object locations: locations specified relative to the observer s location

8 Reference Systems Object-to-object locations: locations specified relative to each other

9 Reference Systems McCloskey: reference frames and the neuropsychological evidence Bisiach & Luzzatti: classic empirical examples of reference frames in perception and/versus representation Shelton & Yamamoto: discuss a variety of topics that inherently require discussion of reference frames Bohbot et al.: learning & reference frames

10 Distortions Draw your neighborhood (or campus) University Parkway University Parkway Remington San Martin Wyman Park Dr. Art Museum Dr. N. Charles St. Paul Remington San Martin Greenway Art Museum Dr. N. Charles St. Paul Tversky, 1981

11 Distortions We tend to take our memories to be correct effective for getting around in space effective for thinking about space However, many examples of how spatial representations are distorted Cardinalizing, hierarchical representations, etc Steven s & Coupe: classic example of subordinate elements using superordinate relationships

12 Distortions Are distortions indicative of bad memory? Think about what you have to do with the information Throwing a ball versus making a turn Right at stop sign to get to the farm.

13 Neural Substrates Cognitive map is used a lot in thinking about spatial representations in the brain What does it mean to say one has a cognitive map? Rat place cells Primate spatial view cells Humans Medial Temporal Lobe

14 Rat Hippocampal Place Cells Neurons respond when rat is in a particular location in the environment Cell fires each time rat moves to that location Spatial tuning maintained over delay In darkness e.g., O Keefe & Nadel, 1975

15 Rat Hippocampal Place Cells Suggests that a map is formed in the brain e.g., O Keefe & Nadel, 1975

16 Primate Spatial View Cells Neurons respond selectively when monkey is viewing a particular portion of space e.g., Rolls et al., 1997, 1999

17 Primate Spatial View Cells Tuning is independent of monkey s location in space Tuning is independent of head direction Response maintained during obstruction or darkness e.g., Rolls et al., 1997, 1999

18 Human Hippocampus Evidence for Place and Spatial View cells in humans (intracranial recordings) Recent focus on what patients with medial temporal lobe (MTL) damage can do Bohbot et al.: MTL patients & spatial learning Focus on the key elements of the task What did performance look like? What does it mean for the kinds of representations that were formed?

19 Neural Substrates Maguire et al.: navigation network Focus on What it means for the complexity of navigation and spatial representation What this network tell us about how navigation works Note: Maguire s use of hippocampus is a little loose, but makes a strong case for a meaningful network that includes medial temporal lobes

20 McCloskey: Representation The Roadmap Shelton & Yamamoto: Spatial Cog & Vision Stevens & Coupe: Distortions DISCUSSION! Bisiach & Luzzatti: Neglect example Maguire et al.: Navigation Network Bohbot et al.: MTL & Spatial Navigation