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SYMPOSIUM
“GESTALTS IN THE BRAIN”
ECVP 2011, TOULOUSE
WEDNESDAY 31ST, AUDITORIUM 9:00-11:00
Symposium overview
Co-organizers: Hans Op de Beeck & Johan Wagemans
Johan Wagemans, Belgium: Gestalts emerging again 100 years later: A modern view on a radical vision
09:20 Pieter Roelfsema, Netherlands: How Gestalt rules constrain the spread of attention in visual cortex
09:45 Mary Peterson, USA: The neural instantiation of Gestalt principlesas uncovered by lesion studies
10:10 Hans Op de Beeck, Belgium: Brain-decoding fMRI reveals the content of neural representations underlying visual Gestalts
10:35 Cees Van Leeuwen, Japan: Restless minds, wandering brains: The neurodynamics of visual awareness
JOHAN WAGEMANS
GESTALTS EMERGING IN THE BRAIN 100 YEARS LATER: A MODERN VIEW ON A RADICAL VISION
LABORATORY OF EXPERIMENTAL PSYCHOLOGY
UNIVERSITY OF LEUVEN
How Gestalt psychology started
Wertheimer, M. (1912). Experimentelle Studien über das Sehen von Bewegung. Zeitschrift fürPsychologie, 61, 161-265.
anecdote
phi motion Steinman, R. M., Pizlo, Z., & Pizlo, F. J. (2000). Phi is not
beta, and why Wertheimer’s discovery launched the Gestalt revolution. Vision Research, 40, 2257-2264.
http//psych.purdue.edu/magniphi/
key role phi as pure motion, not a displacement between
two objects phi as a process, “an across in itself”, that cannot
be composed from the usual optical contents
Max Wertheimer(1880-1943)
A radical vision
emerging Gestalt theory Gestalts emerging in the brain
not Gestalt qualities added to the primary sensations not Gestalts as more than the sum of the parts but Gestalts as different from the sum of the parts often the whole is grasped even before the individual parts enter
consciousness a structured unit emerges as a whole
psychological facts and physiological hypotheses went hand-in-hand continuous whole-processes rather than associated combinations
of elementary excitations specifically: some kind of physiological short circuit, and a
flooding back of the current flow, creating a unitary continuouswhole-process
Some early Gestalt history
Koffka, K. (1915). Beitrage zur Psychologie der Gestalt. III. Zur Grundlegung der Wahrnehmungspsychologie. Eine Auseinandersetzung mit V. Benussi. Zeitschrift für Psychologie, 73, 11-90.
implications of this view
primary relations no longer stimulus ~ sensation but stimulus pattern ~ perceived whole
perceived wholes not constructed in the mind from elementary
sensations but direct experience-correlates emerging in the
brain
Kurt Koffka(1886-1941)
Some early Gestalt history
Köhler, W. (1920). Die physischen Gestalten in Ruhe und im stationären Zustand. Eine natur-philosophische Untersuchung. Braunschweig, Germany: Vieweg.
decisive step: real physical Gestalts in the brain
strong Gestalts the mutual dependence among the parts is so great that
no displacement or change of state is possible without influencing all the other parts of the system
in fact: there are no parts at all, only interactingmoments of structure that carry one another
psychophysical isomorphism psychological facts and the brain events that underlie
them are similar in all of their structural characteristics specifically: visual Gestalts result from a single Gestalt
process in which the whole optic sector from the retina onwards is involved, including transverse functionalconnections
in fact: the brain described as a self-organizing physicalsystem
WolfgangKöhler
(1887-1967)
From speculation to facts
Köhler, W., & Held, R. (1949). The cortical correlate of pattern vision. Science, 110, 414-419.
previously: indirect evidence from “figural aftereffects” (with Hans Wallach)
now: first recordings of visual currents, picked up by an electrode at the scalp of human observers
from “electromotive forces” to “electrical field theory”
flow of current is “relational” the field of distribution of current
flow is “molar” the characteristics of perceptual
organization correspond to the distribution of current dense, continuous flow ~ figure interruption of flow or sharp
intensity gradient ~ contour
From speculation to facts
Lashley, K. S., Chow, K. L., & Semmes, J. (1951). An examination of the electrical field theory of cerebral integration. Psychological Review, 58, 123-136.
more direct test of electrical field theory rationale: insulate part of a cortical field and test for consequent
disturbances of function metallic strips and pins inserted in macaque cortex almost no effect on post-operative retention of object discrimination
End of electrical field theory
similar study with slightly different methods but same results:Sperry, R. W., Miner, N., & Myers, R. E. (1955). Visual pattern perception following subpial slicing
and tantalum wire implantations in the visual cortex. Journal of Comparative and Physiological Psychology, 48, 50-58.
Köhler’s reactions to these studies (pointing out several methodologicaland conceptual shortcomings) were basically ignored
devastating blow to electrical field theory basic isomorphism postulate of Gestalt theory
Single-neuron doctrine
Hubel & Wiesel: big success
Barlow, H. (1972): Single units and sensation: A neuron doctrine forperceptual psychology. Perception, 1, 371-394.
our perceptions are caused by the activity of a small number of neurons the activity of a single neuron is related quite simply to our subjective
experience
reductionist, elementalist approach which Gestalt theorists had banished
mapping of responses of single neurons in LGN, striateand extrastriate cortex in catand monkey
tuning to simple stimulus attributes (e.g., orientation)
single neurons interpreted as “feature detectors” (e.g., linedetectors, edge detectors)
Further developments
single-unit recording flourished tuning properties of different types of cells in different areas of
the brain functional specialization hierarchical organization
retinotopy decreases invariance increases complexity of the “features” increases
confirmed in human fMRI (modules, maps) standard view
Felleman, D. J., & Van Essen, D. C. (1991). Distributed hierarchical processing in the primate cerebral cortex. Cerebral Cortex, 1, 1-47.
Grill-Spector, K., & Malach, R. (2004). The human visual cortex. Annual Review of Neuroscience, 27, 649-677.
Serre, T., Oliva, A., & Poggio, T. (2007). A feedforward architecture accounts for rapid categorization. Proceedings of the National Academy of Science of the USA, 104,6424-6429.
Felleman, D. J., & Van Essen, D. C. (1991). Distributed hierarchicalprocessing in the primate cerebral cortex. Cerebral Cortex, 1, 1-47.
Grill-Spector, K., & Malach, R. (2004). The human visual cortex. Annual Review of Neuroscience, 27, 649-677.
Serre, T. et al. (2007). A feedforward architecture accounts for rapid categorization. PNAS, 104, 6424-6429.
Re-emergence of Gestalt issues
surround influences from outside classic receptive field (cRF) Allman, J., Miezin, F., & McGuinness, E. (1985). Direction- and velocity-
specific responses from beyond the classical receptive field in the middle temporal visual area (MT). Perception, 14, 105-126.
neural responses to illusory contours von der Heydt, R., Peterhans, E., & Baumgartner, G. (1984). Illusory
contours and cortical neuron responses. Science, 224, 1260-1262.
neural responses to figure-ground organization Lamme, V. A. F. (1995). The neurophysiology of figure-ground segregation
in primary visual cortex. Journal of Neuroscience, 15, 1605-1615. Zhou, H., Friedman, H. S., & von der Heydt, R. (2000). Coding of border-
ownership in monkey visual cortex. Journal of Neuroscience, 20, 6594-6611.
Allman, J. et al. (1985). Direction- and velocity-specific responses from beyond the classical receptive field in the middle temporal visual area (MT).
Perception, 14, 105-126.
Allman, J. et al. (1985). Direction- and velocity-specific responses from beyond the classical receptive field in the middle temporal visual area (MT).
Perception, 14, 105-126.
von der Heydt, R. et al. (1984). Illusory contours and cortical neuron responses. Science, 224, 1260-1262.
Zhou, H. et al. (2000). Coding of border-ownership in monkey visual cortex. Journal of Neuroscience, 20, 6594-6611.
20
Lamme, V. A. F. (1995). The neurophysiology of figure-ground segregationin primary visual cortex. Journal of Neuroscience, 15, 1605-1615.
Larger implications
how to fit these findings into the standard view?
general discussions Spillmann, L. (1999). From elements to perception: Local and global
processing in visual neurons. Perception, 28, 1461-1492. Ehrenstein, W. H., Spillman, L., & Sarris, V. (2003). Gestalt issues in
modern neuroscience. Axiomathes, 13, 433-458. Spillmann, L. (2009). Phenomenology and neurophysiological correlations:
Two approaches to perception research. Vision Research, 49, 1507-1521. specific models
Roelfsema, P. R., Lamme, V. A. F., Spekreijse, H., & Bosch, H. (2002). Figure-ground segregation in a recurrent network architecture. Journal of Cognitive Neuroscience, 14, 525-537.
Kogo, N., Strecha, C., Van Gool, L., & Wagemans, J. (2010). Surface construction by a 2-D differentiation-integration process: A neurocomputational model for perceived border-ownership, depth, and lightness in Kanizsa figures. Psychological Review, 117, 406-439.
A modern view on a radical vision
more general models Hochstein, S., & Ahissar, M. (2002). View from the top:
Hierarchies and reverse hierarchies in the visual system. Neuron, 36, 791-804.
Bar, M. et al. (2006). Top-down facilitation of visual recognition.Proceedings of the National Academy of Science of the USA, 103,449-454.
interesting characteristics from viewpoint of Gestalt theory “global” comes first highly interactive highly dynamic not limited to visual areas
Hochstein, S., & Ahissar, M. (2002). View from the top: Hierarchies and reverse hierarchies in the visual system. Neuron, 36, 791-804.
Bar, M. et al. (2006). Top-down facilitation of visual recognition. PNAS, 103, 449-454.
Remaining challenges
interplay between bottom-up processing lateral interactions feedback processing
different types of Gestalts how to do justice to Gestalt phenomena like
configural superiority effects global precedence/dominance effects
relation to visual awareness creating/constructing Gestalts versus emerging Gestalts cortical dynamics
synchronization coherence intervals traveling waves
Symposium overview
09:20 Pieter Roelfsema, Netherlands: How Gestalt rulesconstrain the spread of attention in visual cortex multiple-unit recordings (implanted electrode arrays)
09:45 Mary Peterson, USA: The neural instantiation of Gestaltprinciples as uncovered by lesion studies brain-damaged patients
10:10 Hans Op de Beeck, Belgium: Brain-decoding fMRI revealsthe content of neural representations underlying visual Gestalts fMRI decoding (MVPA)
10:35 Cees Van Leeuwen, Japan: Restless minds, wanderingbrains: The neurodynamics of visual awareness cortical dynamics (EEG and MEG)
