HOW ARE COGNITIVE MAPS REPRESENTED IN THE BRAIN?

HOW ARE COGNITIVE MAPS REPRESENTED IN THE BRAIN? VISUAL VS. PROPOSITIONAL REPRESENTATIONS AND IMPLICATIONS FOR GPS TECHNOLOGY Serj Mooradian Alison Wheatley Becky Wright Jane Emerton Penelope Dimitrakopoulou

INTRODUCTION 

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Behaviourism: from the 1920’s onward, behaviour was explained in terms of simple stimulus-response mechanisms. Rats learnt mazes by linking rewards (stimulus; i.e. food) with muscle movements (response; i.e. running in particular directions). Tolman (1932) cast doubt on this theory – rats in mazes: swimming versus running. The researchers concluded that rats construct a ‘cognitive map’ in their brains, and use the internal representation to solve mazes.

MORE ABOUT COGNITIVE MAPPING 

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A cognitive map is a cognitive representation of an environment, that is built up whenever a person encounters a novel environment (Lynch, 1960). It can comprise of landmarks, nodes, and paths. The more experience a person has with an environment, the better their cognitive map (Jacobson et al 2001). The type and content of how this information is represented in the brain is still a prominent and controversial debate. There appears at present to be two main arguments – those who believe cognitive maps are represented pictorially vs. those who believe they are represented propositionally.

HOW ARE COGNITIVE MAPS REPRESENTED IN THE BRAIN?        

1. PICTORIAL vs. PROPOSITIONAL Type and content of cognitive maps is still being debated Pictorial – Kosslyn Depiction of environment Implicates visual system in production and processing – the ‘minds eye’ Propositional – Pylyshyn Similar to language Syntactical representation

PROPOSITIONAL

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vs.

PICTORIAL

North, (TREE, HOUSE) South (LAKE, HOUSE)

-Linguistic description of relationships -Discrete symbols -Requires a symbols to describe the relationships -Follows grammatical rules -Abstract symbols -Unambiguous -Multiple modes of perception

-More easily accessible -Does not require knowledge of language -Not discrete symbols -Does not require a symbol to describe the relationships -Concrete symbols -Ambiguous -Only visual mode of perception

EARLY COGNITIVE MAP EXPERIMENTS  

Images cannot be directly observed so study brain at functional level Kosslyn et al (1978)– Mental Image Scanning Tasks  Method    

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Results 

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Memorise a map of 7 locations Focus on a location Decide if a second location was on the map Picture a black speck moving between the two locations Scanning time increased linearly with the distance between the two locations

Conclusion  

It takes longer to scan larger distances compared to small if images are depictions Images are depictive rather than descriptive and have spatial properties

EARLY EXPERIMENTS cont. ALTERNATIVE MODEL 

Pylyshyn (1981) – Critique of Kosslyn’s Experiments   

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Experiment 

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Participants asked to see a scene Use knowledge about really world to simulate events Does not tell us about inherent nature of imaging Scanning phenomenon vanishes when asked to judge direction Can switch attention between locations without simulating moving Distance between locations had no effect on response time of direction

Conclusion  

Unclear which properties are due to the inherent nature of the mental imaging system and its mechanism Or which properties are ‘cognitively penetrable’ by the person’s own knowledge and beliefs during imagery.

NEW TECHNOLOGY GIVES US A ‘WINDOW INTO THE MIND’ Attempts to solve debate via behavioural methods had led researchers down a ‘cul-de-sac’. However…. Advances in technology offered a new opportunity. Opened up a “window into the mind”.

PET (POSITRON EMISSION TOMOGRAPHY) ~ ²/3 of activation shared by vision and imagery. (Kosslyn, Thompson & Alpert, 1997) However, PET not very precise. 

rTMS (Repetitive Transcranial Magnetic Stimulation)

Applying rTMS to the occipital cortex causes temporary impairment of visual mental imagery (Kosslyn et al., 1999).

PYLYSHYN’S RESPONSE Pylyshyn (2002): Possible visual system can be involved in both vision and mental imagery but without generating a picture-like representation. “It is important not only that such … areas be involved in imagery, but also that their involvement be of the right sort – that the way their topographical organization is involved reflects the spatial properties of the image…” (Pylyshyn, 2002, p.175)

RETINOTOPICALITY Area 17:

Located in the occipital lobe. Involved in early visual processing e.g. shape, location.

Activity is distributed according to a ‘functional space’ i.e. the spatial properties of the visual scene are reflected in the spatial patterns of the brain activity (Kosslyn, 1994).

Visual Spatial Spectrum: TOP

RIGHT SIDE

BOTTOM

FUNCTIONAL SPACE: Different spatial areas within the visual field reflected onto the retina….

Adapted from Slotnick et al (2005)

… result in activation in different primary visual areas.

Q. DOES THE RETINOTOPICAL ACTIVITY FOUND IN VISION ALSO OCCUR DURING MENTAL IMAGERY?

Klein et al (2004), Slotnick et al (2005); • fMRI study (Functional Magnetic Resolution Imaging) • Used simple visual stimuli:

Asked participants to both visualise and imagine the stimuli.

Vertical-axis space = red & green areas

Vision

Horizontal-axis space = blue & yellow areas

Imagery

Adapted from Slotnick et al (2005)

PYLYSHYN’S RESPONSE TO KOSSLYN  

Kosslyn’s findings have not been replicated They are inherently biased Participants were asked to visualize an image  By visualizing an image, they are being asked to ‘see it’ and hence their visual cortex must be stimulated 

PYLYSHYN’S RESPONSE TO KOSSLYN cont. 

Visual images are caused by a response to light on the retina and mental imagery is a top-down process from higher cortical processes 

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It is unlikely that the same response will occur to both types of imagery

Kosslyn: literally pictures in the brain If it takes longer to ‘scan’ greater imagined distance (time=distance/speed)  i.e. simulation of ‘real space’ 

PYLYSHYN’S RESPONSE TO KOSSLYN cont. 

Other differences in how visual and mental images are accessed: Signature properties  Manipulations of mental images not accurate  Cortical images fade more quickly  Emmert’s Law  Two forms of images not connected to the motor system in the same way (reaching for an object)  Retinal images are pre-interpretation; mental images are the interpretation 

PYLYSHYN’S RESPONSE TO KOSSLYN cont. 

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Cognitive maps are developed by being in the environment, receiving cues, interpreting route cues as opposed to visual, pictorial cues on a map Use propositional knowledge to navigate, as it is needed 

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Can be pictorial, but isn’t by nature

Blind people are able to form cognitive maps (Landau, 1986) 

The experience of moving through an environment is enough to form a cognitive map, without actually navigating the environment (Millar, 1994)

PYLYSHYN’S RESPONSE TO KOSSLYN cont. 

When one is driving down the M4, one does not necessarily visualize a map of the M4 going EastWest and taking exit 18 south to bath, one simply exits at exit 18 and drives (subconscious behaviour) 

One accesses one’s cognitive map of the region without stimulating the visual cortex (however it is (hopefully) stimulated by the road ahead – but not terms of the cognitive map)

GLOBAL POSITIONING SYSTEMS 

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GPS’s are a network of satellites and computers that can locate, track and monitor any mobile object/individual on earth GPS in cars provide the user with a pictorial map and auditory directions GPS is normally a navigation tool However - if we regard GPS as simply an aid for cognitive map development…

IMPLICATIONS FOR THE DESIGN OF GLOBAL POSITIONING SYSTEMS (GPS)

… if Kosslyn is right:  GPS technology should display visual information….  However, a visual display may turn out to be more of a hindrance than a help. Kosslyn (1985) found evidence that visual information similar to that of a mental representation can actually interfere with the cognitive map.

IMPLICATIONS FOR THE DESIGN OF GLOBAL POSITIONING SYSTEMS (GPS)

…if Pylyshyn is right:  GPS technology should provide auditory information

GPS TECHNOLOGY cond. 

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London cabbies  Accuracy/reliability of GPS??  Knowledge of road closures, etc. GPS instead of training or to aid training? Navigation vs. cognitive maps

Pictorial vs Propositional debate has not been resolved yet Although taxi drivers may not find GPS useful on the job, there is much agreement that it can be useful to develop cognitive maps in training. Cognitive maps prove to be pictorial or propositional in nature (or a combination of both). This will have implications as how best to develop future technology.

REFERENCES 

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Jacobson, D., Lippa, Y., Golledge, R.G., Kitchin, R., & Blades, M. (2001). Rapid development of cognitive maps in people with visual impairments when exploring novel geographic spaces. Bulletin of people-environment studies, 1-8. Klein, I., Dubois, J., Mangin, J-F., Kherif, F., Flandin, G., Poline, J-B., Denis, M., Kosslyn, S. M., Le Bihan, D. (2004). Retinotopic organization of visual mental images as revealed by functional magnetic resonance imaging. Cognitive Brain Research, 22, 26-31. Kosslyn, S. M. (1983). Ghosts in the Mind’s Machine. Creating and using images in the brain. George J. McLeod Limited, Toronto. Kosslyn, S. M., Ball, T.M. and Reiser, B. J. (1978). Visual images preserve metric spatial information: Evidence from studies of image scanning. Journal of Experimental Psychology: Human Perception and Performance, 4, 47-60. Kosslyn, S. M., Pascual-Leone, A., Felician, O., Camposano, S., Keenan, J. P., Thompson, W. L., Ganis, G., Sukel, K. E., and Alpert, N. M. (1999). The role of area 17 in visual imagery: Convergent evidence from PET and rTMS. Science, 284, 167-170. Kosslyn, S. M., Thompson, W. L., and Alpert, N. M. (1997). Neural systems shared by visual imagery and visual perception: A positron emission tomography study. NeuroImage, 6, 320-334. Landau, B. (1996). Early map use as an unlearned ability. Cognition, 22, 201-223.

REFERENCES cont. 

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Lynch, K. (1960). The image of the city. Cambridge, MA: M.I.T. Press. Millar, S. (1994). Understanding and representing space theory and evidence from studies with blind and sighted children. New York: Oxford University Press. Pylyshyn, Z. (2000). Is the "imagery debate" over? If so, what was it about? In: E. Dupoux (ed.). Cognition: a critical look. Advances, questions and controversies in honor of J. Mehler. Cambridge, MA, MIT Press. Available online at: http://ruccs.rutgers.edu/ftp/pub/papers/pylyshynmehler.pdf Pylyshyn, Z. (2003). Return of the mental image: are there really pictures in the brain? Trends in Cognitive Sciences, 7(3), 113-118. Pylyshyn, Z.W. (2002). Mental Imagery: In search of a theory. Behavioral Brain Science, 25, 157238. Slotnick, S. D., Thompson, W. L., and Kosslyn, S. M. (2005). Visual Mental Imagery Induces Retinotopically Organized Activation of Early Visual Areas. Cerebral Cortex, 15, 1570-1583. Tolman, E.C. (1932). Purposive behavior in animals and men. Berkeley, CA: University of California Press.