-
George Graham.
Behaviorism.
In Edward N. Zalta, editor, The Stanford Encyclopedia of Philosophy.
2002.
Keywords: behaviorism,
philosophy.
| Abstract: It has sometimes been said that "behave is what organisms do." Behaviorism is built on this assumption, and its goal is to promote the scientific study of behavior. In this entry I consider different types of behaviorism. I outline reasons for and against being a behaviorist. I consider contributions of behaviorism to the study of behavior. Special attention is given to the so-called "radical behaviorism" of B. F. Skinner (1904-90). |
@InCollection{grah_02,
author = {Graham, George},
title = {Behaviorism},
booktitle = {The Stanford Encyclopedia of Philosophy},
editor = {Edward N. Zalta},
url = {http://plato.stanford.edu/archives/fall2002/entries/behaviorism/},
year = {2002},
rating = {C},
keywords = {behaviorism, philosophy},
abstract = {It has sometimes been said that "behave is what organisms do." Behaviorism is built on this assumption, and its goal is to promote the scientific study of behavior. In this entry I consider different types of behaviorism. I outline reasons for and against being a behaviorist. I consider contributions of behaviorism to the study of behavior. Special attention is given to the so-called "radical behaviorism" of B. F. Skinner (1904-90). }
}
-
Susan Blackmore.
Crossing the chasm of consciousness.
TRENDS in Cognitive Sciences,
6(7),
2002.
Keywords: philosophy,
neuroscience,
consciousness.
| Comments: Compte-rendu de la conf Tucson 2002: Bach-Y-Rita, Sur, Noë, Gallese, Brooks... |
@ARTICLE{blac_02,
AUTHOR = {Blackmore, Susan},
TITLE = {Crossing the chasm of consciousness},
JOURNAL = {{TRENDS} in Cognitive Sciences},
Volume = {6},
Number = {7},
YEAR = {2002},
comments = {Compte-rendu de la conf Tucson 2002: Bach-Y-Rita, Sur, Noë, Gallese, Brooks...},
keywords = {philosophy, neuroscience, consciousness},
rating = {D}
}
-
S. J. Blakemore,
D. M. Wolpert,
and C. D. Frith.
Abnormalities in the awareness of action.
Trends Cogn Sci,
6(6):237-242,
2002.
Keywords: neuroscience,
action,
awareness.
| Abstract: Optimal motor control relies on internal representations of the actual, desired and predicted states of our limbs and the external world. Only certain components of these internal representations are available to awareness. We suggest that impairments of the components of internal representations might underlie a broad variety of neuropsychiatric symptoms, including the anarchic hand sign, phantom limbs, utilization behaviour and delusions of control. |
@Article{frit_blak_wolp_00,
Author = {Blakemore, S. J. and Wolpert, D. M. and Frith, C. D.},
Title = {Abnormalities in the awareness of action},
Journal = {Trends Cogn Sci},
Volume = {6},
Number = {6},
Pages = {237-242},
Year = {2002},
Abstract = {Optimal motor control relies on internal representations of the actual, desired and predicted states of our limbs and the external world. Only certain components of these internal representations are available to awareness. We suggest that impairments of the components of internal representations might underlie a broad variety of neuropsychiatric symptoms, including the anarchic hand sign, phantom limbs, utilization behaviour and delusions of control.},
rating = {C},
keywords = {neuroscience, action, awareness},
url = {http://www.hera.ucl.ac.uk/sml/publications/papers/FriBlaWol00.pdf}
}
-
Gershon Buchsbaum and Orin Bloch.
Color categories revealed by non-negative matrix factorization of Munsell color spectra.
Vision Research,
42:559-563,
2002.
Keywords: color.
| Abstract: Non-negative matrix factorization (NMF, Nature 401 (1999) ) is a method to derive non-negative basis functions for sets of data that are inherently non-negative, such as color spectra. We applied NMF to Munsell color spectra and investigated the color names associated with the non-negative basis functions. NMF yields basis functions compatible with established color naming categories. |
| Comments: La décomposition positive de l'espace des réflectances de Munsell se réparti assez bien dans les catégories de couleurs |
@Article{busc_bloc_02,
author = {Buchsbaum, Gershon and Bloch, Orin},
title = {Color categories revealed by non-negative matrix factorization of Munsell color spectra},
journal = {Vision Research},
year = {2002},
volume = {42},
pages = {559-563},
abstract = {Non-negative matrix factorization (NMF, Nature 401 (1999) ) is a method to derive non-negative basis functions for sets of data that are inherently non-negative, such as color spectra. We applied NMF to Munsell color spectra and investigated the color names associated with the non-negative basis functions. NMF yields basis functions compatible with established color naming categories.},
comments = {La décomposition positive de l'espace des réflectances de Munsell se réparti assez bien dans les catégories de couleurs},
keywords = {color},
rating = {C},
url = {http://else.hebis.de/cgi-bin/sciserv.pl?collection=journals&journal=00426989&issue=v42i0005}
}
-
Ian Davies and Anna Franklin.
Categorical similarity may affect colour pop-out in infants after-all.
British Journal of Developmental Psychology,
20:185-203,
2002.
Keywords: color,
perception,
ontogenesis.
| Abstract: Gerhardstein, Renner, and Rovee-Collier (1999) reported an investigation of pop-out in infant visual search with targets differing in colour from the distractors. They varied the perceptual distance between target and distractors and their categorical relationship. Targets were either in the same category as distractors or in a different category. They reported that at 3 months, infants showed increased pop-out as perceptual distance increased, but there was no categorical effect. Here, we argue that their stimuli were not adequate to address these issues. Use of incandescent light rather than the normal illuminant C differentially affected the perceptual differences among their stimuli, and there may have been an unintended category boundary present in an intended within category pair. We argue that these faults in the stimuli can account for their pattern of results. They were aware of the possible consequences of using incandescent light and ran a preliminary study on adults comparing category membership and perceived similarity among their stimuli under incandescent light and illuminant C. They report that the illuminant had no effect. We replicated and extended their adult study and found that there were effects of the illuminant as well as evidence consistent with the unintended boundary. Reasons for the discrepant results are discussed, and the requirements for a valid investigation outlined. |
@Article{davi_fran_02,
author = {Davies, Ian and Franklin, Anna},
title = {Categorical similarity may affect colour pop-out in infants after-all},
journal = {British Journal of Developmental Psychology},
year = {2002},
volume = {20},
pages = {185-203},
comments = {},
rating = {D},
url = {http://www.psy.surrey.ac.uk/staff/a.franklin/Davies%20&%20Franklin%20infant%20popout.pdf},
keywords = {color, perception, ontogenesis},
abstract = {Gerhardstein, Renner, and Rovee-Collier (1999) reported an investigation of pop-out in infant visual search with targets differing in colour from the distractors. They varied the perceptual distance between target and distractors and their categorical relationship. Targets were either in the same category as distractors or in a different category. They reported that at 3 months, infants showed increased pop-out as perceptual distance increased, but there was no categorical effect. Here, we argue that their stimuli were not adequate to address these issues. Use of incandescent light rather than the normal illuminant C differentially affected the perceptual differences among their stimuli, and there may have been an unintended category boundary present in an intended within category pair. We argue that these faults in the stimuli can account for their pattern of results. They were aware of the possible consequences of using incandescent light and ran a preliminary study on adults comparing category membership and perceived similarity among their stimuli under incandescent light and illuminant C. They report that the illuminant had no effect. We replicated and extended their adult study and found that there were effects of the illuminant as well as evidence consistent with the unintended boundary. Reasons for the discrepant results are discussed, and the requirements for a valid investigation outlined.}
}
-
Vebjorn Ekroll,
Franz Faul,
Reinhard Niederee,
and Eike Richter.
The natural center of chromaticity space is not always achromatic: a new look at color induction.
Proc Natl Acad Sci U S A,
99(20):13352-6,
2002.
Keywords: color,
perception,
color constancy.
| Abstract: Although current theories of color vision differ in many respects, they all assume the existence of a uniquely defined neutral point in chromaticity space. It generally is assumed that this point satisfies several criteria simultaneously. One of these criteria is that it is perceived as achromatic. A further criterion shared by most theories is the structural assumption that lines in chromaticity space of constant hue converge on the neutral point. The basic assumption that these two criteria coincide is clearly true for isolated spots of light presented in darkness, and it usually is taken for granted that this coincidence generalizes to more complex visual stimuli. Here, we show that this is not the case. Our experiments with infields in chromatic surrounds revealed that the point in chromaticity space that appears gray is clearly different from the point on which lines of constant hue converge. A plausible interpretation of this apparently paradoxical finding in terms of color scission is proposed. |
| Comments: à la fois absurde et intéressant: mise en regard de deux expériences dans lesquelles le système nerveux n'a pas accès à la même quantité d'information, et conclusion tirée à partir de l'évidente différence de résultat sur l'existence de deux percepts... |
@Article{ekro_02,
author = {Ekroll, Vebjorn and Faul, Franz and Niederee, Reinhard and Richter, Eike},
title = { The natural center of chromaticity space is not always achromatic: a new look at color induction},
journal = {Proc Natl Acad Sci U S A},
year = {2002},
volume = {99},
number = {20},
pages = {13352-6},
comments = {à la fois absurde et intéressant: mise en regard de deux expériences dans lesquelles le système nerveux n'a pas accès à la même quantité d'information, et conclusion tirée à partir de l'évidente différence de résultat sur l'existence de deux percepts...},
rating = {C},
url = {http://www.pnas.org/cgi/content/full/99/20/13352},
keywords = {color, perception, color constancy},
abstract = {Although current theories of color vision differ in many respects, they all assume the existence of a uniquely defined neutral point in chromaticity space. It generally is assumed that this point satisfies several criteria simultaneously. One of these criteria is that it is perceived as achromatic. A further criterion shared by most theories is the structural assumption that lines in chromaticity space of constant hue converge on the neutral point. The basic assumption that these two criteria coincide is clearly true for isolated spots of light presented in darkness, and it usually is taken for granted that this coincidence generalizes to more complex visual stimuli. Here, we show that this is not the case. Our experiments with infields in chromatic surrounds revealed that the point in chromaticity space that appears gray is clearly different from the point on which lines of constant hue converge. A plausible interpretation of this apparently paradoxical finding in terms of color scission is proposed.}
}
-
M.S. Lewicki.
Efficient coding of natural sounds.
Nature Neuroscience,
5(4):356-363,
2002.
Keywords: sounds,
ICA.
| Abstract: The auditory system encodes sound by decomposing the amplitude signal arriving at the ear into multiple frequency bands whose center frequencies and bandwidths are approximately exponential functions of the distance from the stapes. This organization is thought to result from the adaptation of cochlear mechanisms to the animal's auditory environment. Here we report that several basic auditory nerve fiber tuning properties can be accounted for by adapting a population of filter shapes to encode natural sounds efficiently. The form of the code depends on sound class, resembling a Fourier transformation when optimized for animal vocalizations and a wavelet transformation when optimized for non-biological environmental sounds. Only for the combined set does the optimal code follow scaling characteristics of physiological data. These results suggest that auditory nerve fibers encode a broad set of natural sounds in a manner consistent with information theoretic principles. |
@Article{lewi_02,
author = {Lewicki, M.S.},
title = {Efficient coding of natural sounds},
journal = {Nature Neuroscience},
year = {2002},
volume = {5},
number = {4},
pages = {356-363},
url = {http://www.cshl.org/labs/brody/SJC/Papers/lewicki_2002.pdf},
rating = {B},
keywords = {sounds, ICA},
abstract = {The auditory system encodes sound by decomposing the amplitude signal arriving at the ear into multiple frequency bands whose center frequencies and bandwidths are approximately exponential functions of the distance from the stapes. This organization is thought to result from the adaptation of cochlear mechanisms to the animal's auditory environment. Here we report that several basic auditory nerve fiber tuning properties can be accounted for by adapting a population of filter shapes to encode natural sounds efficiently. The form of the code depends on sound class, resembling a Fourier transformation when optimized for animal vocalizations and a wavelet transformation when optimized for non-biological environmental sounds. Only for the combined set does the optimal code follow scaling characteristics of physiological data. These results suggest that auditory nerve fibers encode a broad set of natural sounds in a manner consistent with information theoretic principles.}
}
-
Beau R. Lotto and Dale Purves.
A rationale for the structure of color space.
Trends in Neurosciences,
25(2):84-88,
2002.
Keywords: color constancy,
color,
perception.
| Abstract: The colors perceived by humans in response to light stimuli are generally described in terms of four color categories (reds, greens, blues and yellows), the members of which are systematically arrayed around gray. This broadly accepted description of color sensation differs fundamentally from the light that induces it, which is neither 'circular' nor categorical. What, then, accounts for these discrepancies between the structure of color experience and the physical reality that underlies it? We suggest that these differences are based on two related requirements for successful color vision: (1) that spectra be ordered according to their physical similarities and differences; and (2) that this ordering be constrained by the four-color map problem. |
| Comments: une explication claire de la différence de structure entre lumiere physique et espace des couleurs, et refs correspondantes. naif pour le reste. |
@Article{lott_purv_02,
author = {Lotto, Beau R. and Purves, Dale},
title = {A rationale for the structure of color space},
journal = {Trends in Neurosciences},
year = {2002},
volume = {25},
number = {2},
pages = {84-88},
comments = {une explication claire de la différence de structure entre lumiere physique et espace des couleurs, et refs correspondantes. naif pour le reste.},
rating = {D},
url = {http://linkinghub.elsevier.com/retrieve/pii/S0166223602020593},
keywords = {color constancy, color, perception},
abstract = {The colors perceived by humans in response to light stimuli are generally described in terms of four color categories (reds, greens, blues and yellows), the members of which are systematically arrayed around gray. This broadly accepted description of color sensation differs fundamentally from the light that induces it, which is neither 'circular' nor categorical. What, then, accounts for these discrepancies between the structure of color experience and the physical reality that underlies it? We suggest that these differences are based on two related requirements for successful color vision: (1) that spectra be ordered according to their physical similarities and differences; and (2) that this ordering be constrained by the four-color map problem.}
}
-
Beau R. Lotto and Dale Purves.
The empirical basis of color perception.
Consciousness and Cognition,
11:609-629,
2002.
Keywords: color constancy,
color,
perception.
| Abstract: Rationalizing the perceptual effects of spectral stimuli has been a major challenge in vision science for at least the last 200 years. Here we review evidence that this otherwise puzzling body of phenomenology is generated by an empirical strategy of perception in which the color an observer sees is entirely determined by the probability distribution of the possible sources of the stimulus. The rationale for this strategy in color vision, as in other visual perceptual domains, is the inherent ambiguity of the real-world origins of any spectral stimulus. |
| Comments: aaah, quand même: "as psychophysicists such as ... have made abundantly clear, the ENTIRE scene is somehow relevant to the perceived color of ANY PART of it." et "reducing simultaneous color contrast to adaptation at the level of retinal receptors, or even at the level of the center/surround physiology characteristic of early visual processing, simply does not account for the full range of contextual effects observed. Thus, is not di cult to create stimuli that elicit perceptions inconsistent, or even opposite, those predicted by color opponent or adaptational mechanisms." |
@Article{lott_purv_02b,
author = {Lotto, Beau R. and Purves, Dale},
title = {The empirical basis of color perception},
journal = {Consciousness and Cognition},
year = {2002},
volume = {11},
pages = {609-629},
comments = {aaah, quand même: "as psychophysicists such as ... have made abundantly clear, the ENTIRE scene is somehow relevant to the perceived color of ANY PART of it." et "reducing simultaneous color contrast to adaptation at the level of retinal receptors, or even at the level of the center/surround physiology characteristic of early visual processing, simply does not account for the full range of contextual effects observed. Thus, is not di cult to create stimuli that elicit perceptions inconsistent, or even opposite, those predicted by color opponent or adaptational mechanisms."},
rating = {B},
url = {http://dx.doi.org/10.1016/S1053-8100(02)00014-4},
keywords = {color constancy, color, perception},
abstract = {Rationalizing the perceptual effects of spectral stimuli has been a major challenge in vision science for at least the last 200 years. Here we review evidence that this otherwise puzzling body of phenomenology is generated by an empirical strategy of perception in which the color an observer sees is entirely determined by the probability distribution of the possible sources of the stimulus. The rationale for this strategy in color vision, as in other visual perceptual domains, is the inherent ambiguity of the real-world origins of any spectral stimulus.}
}
-
Antoine Lutz,
Jean-Philippe Lachaux,
Jacques Martinerie,
and Francisco J. Varela.
Guiding the study of brain dynamics by using first-person data: Synchrony patterns correlate with ongoing conscious states during a simple visual task.
PNAS,
99(3):1586-1591,
2002.
Keywords: enaction,
psychology.
| Abstract: Even during well-calibrated cognitive tasks, successive brain responses to repeated identical stimulations are highly variable. The source of this variability is believed to reside mainly in fluctuations of the subject's cognitive "context" defined by his/her attentive state, spontaneous thought process, strategy to carry out the task, and so on ... As these factors are hard to manipulate precisely, they are usually not controlled, and the variability is discarded by averaging techniques. We combined first-person data and the analysis of neural processes to reduce such noise. We presented the subjects with a three-dimensional illusion and recorded their electrical brain activity and their own report about their cognitive context. Trials were clustered according to these first-person data, and separate dynamical analyses were conducted for each cluster. We found that (i) characteristic patterns of endogenous synchrony appeared in frontal electrodes before stimulation. These patterns depended on the degree of preparation and the immediacy of perception as verbally reported. (ii) These patterns were stable for several recordings. (iii) Preparatory states modulate both the behavioral performance and the evoked and induced synchronous patterns that follow. (iv) These results indicated that first-person data can be used to detect and interpret neural processes. |
@article{lutz_02,
author = {Lutz, Antoine and Lachaux, Jean-Philippe and Martinerie, Jacques and Varela, Francisco J.},
title = {Guiding the study of brain dynamics by using first-person data: Synchrony patterns correlate with ongoing conscious states during a simple visual task},
journal = {PNAS},
volume = {99},
number = {3},
pages = {1586-1591},
year = {2002},
abstract = {Even during well-calibrated cognitive tasks, successive brain responses to repeated identical stimulations are highly variable. The source of this variability is believed to reside mainly in fluctuations of the subject's cognitive "context" defined by his/her attentive state, spontaneous thought process, strategy to carry out the task, and so on ... As these factors are hard to manipulate precisely, they are usually not controlled, and the variability is discarded by averaging techniques. We combined first-person data and the analysis of neural processes to reduce such noise. We presented the subjects with a three-dimensional illusion and recorded their electrical brain activity and their own report about their cognitive context. Trials were clustered according to these first-person data, and separate dynamical analyses were conducted for each cluster. We found that (i) characteristic patterns of endogenous synchrony appeared in frontal electrodes before stimulation. These patterns depended on the degree of preparation and the immediacy of perception as verbally reported. (ii) These patterns were stable for several recordings. (iii) Preparatory states modulate both the behavioral performance and the evoked and induced synchronous patterns that follow. (iv) These results indicated that first-person data can be used to detect and interpret neural processes. },
url = {http://www.pnas.org/cgi/reprint/99/3/1586.pdf},
rating = {C},
keywords = {enaction, psychology}
}
-
Donald I.A. MacLeod.
Influence of Scene Statistics on Colour Constancy.
Nature,
415:637--640,
2002.
Keywords: color,
perception,
color constancy.
| Abstract: The light reflected from an object depends not only on the surface properties of this object but also on the illuminant. The same is true for the excitations of the photoreceptors, which serve as the basis for the perceived colour. However, our visual system has the ability to perceive constant surface colours despite changes in illumination1. The average chromaticity of the retinal image of a scene depends on the illumination, and thus might be used by the visual system to estimate the illumination and to modulate the correction that subserves colour constancy. But this measure is not sufÆcient: a reddish scene under white light can produce the same mean stimulation as a neutral scene in red light. Higher order scene statistics for example, the correlation between redness and luminance within the image allow these cases to be distinguished. Here we report that the human visual system does exploit such a statistic when estimating the illuminant, and gives it a weight that is statistically appropriate for the natural environment. |
| Comments: amélioration des algorithmes à la Kries, où l'illuminant est estimé non-seulement sur la base de la moyenne chromatique, mais aussi de sa variance. |
@Article{macl_02,
author = {MacLeod, Donald I.A.},
title = {Influence of Scene Statistics on Colour Constancy},
journal = {Nature},
year = {2002},
volume = {415},
pages = {637--640},
comments = {amélioration des algorithmes à la Kries, où l'illuminant est estimé non-seulement sur la base de la moyenne chromatique, mais aussi de sa variance.},
rating = {C},
url = {http://aardvark.ucsd.edu/color/nature.pdf},
keywords = {color, perception, color constancy},
abstract = {The light reflected from an object depends not only on the surface properties of this object but also on the illuminant. The same is true for the excitations of the photoreceptors, which serve as the basis for the perceived colour. However, our visual system has the ability to perceive constant surface colours despite changes in illumination1. The average chromaticity of the retinal image of a scene depends on the illumination, and thus might be used by the visual system to estimate the illumination and to modulate the correction that subserves colour constancy. But this measure is not sufÆcient: a reddish scene under white light can produce the same mean stimulation as a neutral scene in red light. Higher order scene statistics for example, the correlation between redness and luminance within the image allow these cases to be distinguished. Here we report that the human visual system does exploit such a statistic when estimating the illuminant, and gives it a weight that is statistically appropriate for the natural environment.}
}
-
Laurence T. Maloney.
Illuminant estimation as cue combination.
Journal of Vision,
2:493-504,
2002.
Keywords: color constancy,
color,
perception.
| Abstract: This work briefly describes a model for illuminant estimation based on combination of candidate illuminant cues. Many of the research issues concerning cue combination in depth and shape perception translate well to the study of surface color perception. I describe and illustrate a particular experimental approach (perturbation analysis) employed in the study of depth and shape that is useful in determining whether hypothetical illuminant cues are actually used in color vision. |
| Comments: "chromaticité de l'illuminant". idée que la perception des couleurs passe par une combinaisons de cues pour estimer cette chromaticité, puis celle des surfaces. |
@Article{malo_02,
author = {Maloney, Laurence T.},
title = {Illuminant estimation as cue combination},
journal = {Journal of Vision},
year = {2002},
volume = {2},
pages = {493-504},
comments = {"chromaticité de l'illuminant". idée que la perception des couleurs passe par une combinaisons de cues pour estimer cette chromaticité, puis celle des surfaces.},
rating = {C},
url = {http://www.psych.nyu.edu/maloney/MaloneyIllumCuesJOV200202.pdf},
keywords = {color constancy, color, perception},
abstract = {This work briefly describes a model for illuminant estimation based on combination of candidate illuminant cues. Many of the research issues concerning cue combination in depth and shape perception translate well to the study of surface color perception. I describe and illustrate a particular experimental approach (perturbation analysis) employed in the study of depth and shape that is useful in determining whether hypothetical illuminant cues are actually used in color vision.}
}
-
Stefano Nolfi and Davide Marocco.
Active Perception: A Sensorimotor Account of Object Categorization.
2002.
Keywords: artificial vision,
artificial intelligence,
active perception.
| Comments: Résultats d'un ensemble d'expériences virtuelles utilisant les lois sensorimotrices (tactiles) pour catégoriser des objets. Tout est supervisé. |
@ARTICLE{anolf_maro_02,
AUTHOR = {Nolfi, Stefano and Marocco, Davide},
TITLE = {Active Perception: A Sensorimotor Account of Object Categorization},
JOURNAL = {},
YEAR = {2002},
abstract = {},
comments = {Résultats d'un ensemble d'expériences virtuelles utilisant les lois sensorimotrices (tactiles) pour catégoriser des objets. Tout est supervisé.},
url = {http://gral.ip.rm.cnr.it/nolfi/papers/nolfi.arm.pdf},
rating = {D},
keywords = {artificial vision, artificial intelligence, active perception}
}
-
Joel Norman.
Two visual systems and two theories of perception: An attempt to reconcile the constructivist and ecological approaches.
Behavioral and Brain Sciences,
25(1):73-144,
2002.
Keywords: vision,
neuroscience,
constructivism,
ecology.
| Abstract: The two contrasting theoretical approaches to visual perception, the constructivist and the ecological, are briefly presented and illustrated through their analyses of space perception and size perception. Earlier calls for their reconciliation and unification are reviewed. Neurophysiological, neuropsychological, and psychophysical evidence for the existence of two quite distinct visual systems, the ventral and the dorsal, is presented. These two perceptual systems differ in their functions; the ventral system\u2019s central function is that of identification, while the dorsal system is mainly engaged in the visual control of motor behavior. The strong parallels between the ecological approach and the functioning of the dorsal system and between the constructivist approach and the functioning of the ventral system are noted. It is also shown that the experimental paradigms used by the proponents of these two approaches match the functions of the respective visual systems. A dual-process approach to visual perception emerges from this analysis, with the ecological-dorsal process transpiring mainly without conscious awareness, while the constructivist-ventral process is normally conscious. Some implications of this dual-process approach to visual-perceptual phenomena are presented, with emphasis on space perception. |
| Comments: Tentative de réconciliations de deux théories de la vision, via l'existence neurobiologique de deux systèmes visuels aux objectifs différents. |
@Article{norm_02,
author = {Norman, Joel},
title = {Two visual systems and two theories of perception: An attempt to reconcile the constructivist and ecological approaches},
journal = {Behavioral and Brain Sciences},
year = {2002},
volume = {25},
number = {1},
pages = {73-144},
abstract = {The two contrasting theoretical approaches to visual perception, the constructivist and the ecological, are briefly presented and illustrated through their analyses of space perception and size perception. Earlier calls for their reconciliation and unification are reviewed. Neurophysiological, neuropsychological, and psychophysical evidence for the existence of two quite distinct visual systems, the ventral and the dorsal, is presented. These two perceptual systems differ in their functions; the ventral system\u2019s central function is that of identification, while the dorsal system is mainly engaged in the visual control of motor behavior. The strong parallels between the ecological approach and the functioning of the dorsal system and between the constructivist approach and the functioning of the ventral system are noted. It is also shown that the experimental paradigms used by the proponents of these two approaches match the functions of the respective visual systems. A dual-process approach to visual perception emerges from this analysis, with the ecological-dorsal process transpiring mainly without conscious awareness, while the constructivist-ventral process is normally conscious. Some implications of this dual-process approach to visual-perceptual phenomena are presented, with emphasis on space perception. },
comments = {Tentative de réconciliations de deux théories de la vision, via l'existence neurobiologique de deux systèmes visuels aux objectifs différents.},
url = {http://www.bbsonline.org/documents/a/00/00/05/11/bbs00000511-00/index.html},
rating = {B},
keywords = {vision, neuroscience, constructivism, ecology}
}
-
Alexandre Pouget,
Sophie Deneve,
and Jean-René Duhamel.
A computational perspective on the neural basis of multisensory spatial representation.
Nature reviews, Neuroscience,
3:741-474,
2002.
Keywords: neuroscience,
space,
basis functions.
| Abstract: We argue that current theories of multisensory representations are inconsistent with the existence of a large proportion of multimodal neurons with gain fields and partially shifting receptive fields. Moreover, these theories do not fully resolve the recoding and statistical issues involved in multisensory integration. An alternative theory, which we have recently developed and review here, has important implications for the idea of 'frame of reference' in neural spatial representations. This theory is based on a neural architecture that combines basis functions and attractor dynamics. Basis function units are used to solve the recoding problem, whereas attractor dynamics are used for optimal statistical inferences. This architecture accounts for gain fields and partially shifting receptive fields, which emerge naturally as a result of the network connectivity and dynamics. |
@Article{poug_dene_duha_02,
author = {Pouget, Alexandre and Deneve, Sophie and Duhamel, Jean-René},
title = {A computational perspective on the neural basis of multisensory spatial representation},
journal = {Nature reviews, Neuroscience},
year = {2002},
volume = {3},
pages = {741-474},
comments = {},
rating = {D},
url = {http://www.bcs.rochester.edu/people/alex/pub/articles/PougetDeneveDuhamelNRN02.pdf},
abstract = {We argue that current theories of multisensory representations are inconsistent with the existence of a large proportion of multimodal neurons with gain fields and partially shifting receptive fields. Moreover, these theories do not fully resolve the recoding and statistical issues involved in multisensory integration. An alternative theory, which we have recently developed and review here, has important implications for the idea of 'frame of reference' in neural spatial representations. This theory is based on a neural architecture that combines basis functions and attractor dynamics. Basis function units are used to solve the recoding problem, whereas attractor dynamics are used for optimal statistical inferences. This architecture accounts for gain fields and partially shifting receptive fields, which emerge naturally as a result of the network connectivity and dynamics.},
keywords = {neuroscience, space, basis functions}
}
-
Geraint Rees,
Gabriel Kreiman,
and Christof Koch.
Neural Correlates of Consciousness in Humans.
Nature Reviews Neuroscience,
3:261-270,
2002.
Keywords: NCC,
neuroscience,
vision.
| Abstract: The directness and vivid quality of conscious experience belies the complexity of the underlying neural mechanisms, which remain incompletely understood. Recent work has focused on identifying the brain structures and patterns of neural activity within the primate visual system that are correlated with the content of visual consciousness. Functional neuroimaging in humans and electrophysiology in awake mokeys indicate that there are important differences between striate and extrastriate visual cortex in how well neural activity correlates with consciousness. Moreover, recent neuroimaging studies indicate that, in addition to these ventral areas of visual cortex, dorsal prefrontal and parietal areas might contribute to conscious visual experience. |
| Comments: Une foule de références sur l'état de la recherche vis-à-vis des corrélats neuronaux de la conscience. Des remarques ultra compromettantes sur la question, jusqu'à la caricature. Alors qu'une lésion de V1 détruit tout accès à l'information visuelle, les lésions de parties spécifiques de V5/MT montrent une suppression séléctive de telles ou telles "consciences de". |
@Article{rees_krei_koch_02,
author = {Rees, Geraint and Kreiman, Gabriel and Koch, Christof},
title = {Neural Correlates of Consciousness in Humans},
journal = {Nature Reviews Neuroscience},
year = {2002},
volume = {3},
pages = {261-270},
abstract = {The directness and vivid quality of conscious experience belies the complexity of the underlying neural mechanisms, which remain incompletely understood. Recent work has focused on identifying the brain structures and patterns of neural activity within the primate visual system that are correlated with the content of visual consciousness. Functional neuroimaging in humans and electrophysiology in awake mokeys indicate that there are important differences between striate and extrastriate visual cortex in how well neural activity correlates with consciousness. Moreover, recent neuroimaging studies indicate that, in addition to these ventral areas of visual cortex, dorsal prefrontal and parietal areas might contribute to conscious visual experience.},
comments = {Une foule de références sur l'état de la recherche vis-à-vis des corrélats neuronaux de la conscience. Des remarques ultra compromettantes sur la question, jusqu'à la caricature. Alors qu'une lésion de V1 détruit tout accès à l'information visuelle, les lésions de parties spécifiques de V5/MT montrent une suppression séléctive de telles ou telles "consciences de".},
url = {http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11967556&dopt=Abstract},
rating = {B},
keywords = {NCC, neuroscience, vision}
}
-
A. Kimball Romney and Tarow Indow.
A model for the simultaneous analysis of reflectance spectra and basis factors of Munsell color samples under D65 illumination in three-dimensional Euclidean space.
Proc Natl Acad Sci U S A,
99(17):11543-11546,
2002.
Keywords: color,
reflectance.
| Abstract: In this paper we present the results of an analysis of the physically measured surface reflectance spectra of 360 matte Munsell chromatic color chips plus 10 flat achromatic vectors corresponding to Munsell value levels 10 (white) to 1 (near black) for a total sample size of 370. Each of the 370 spectra was multiplied by the spectral radiant power distribution of D65 light so that the final results represent the spectra of reflected light from Munsell color chips under D65 illumination. We simultaneously model the structure of the color chips and the spectra in a common three-dimensional Euclidean space, oriented to yield the most interpretable structure with respect of the Munsell color structure. In this orientation, axis 1 roughly corresponds to the mean power of the spectral reflectance (approximate Munsell value), axis 2 goes from Munsell red to blue-green, and axis 3 goes from Munsell green-yellow to purple. Basis factors for the spectra are also plotted against wavelength and Munsell hue. These plots have implications for theories of opponent processes. By plotting the chips and spectra in the same space we obtain virtually exact correspondences between the various Munsell hues and spectral values in nanometers for comparison to those obtained by previous researchers. Mathematical derivations are provided to validate the common Euclidean model. |
@Article{romn_indo_02,
author = {Romney, A. Kimball and Indow, Tarow},
title = {A model for the simultaneous analysis of reflectance spectra and basis factors of Munsell color samples under D65 illumination in three-dimensional Euclidean space},
journal = {Proc Natl Acad Sci U S A},
year = {2002},
volume = {99},
number = {17},
pages = {11543-11546},
abstract = {In this paper we present the results of an analysis of the physically measured surface reflectance spectra of 360 matte Munsell chromatic color chips plus 10 flat achromatic vectors corresponding to Munsell value levels 10 (white) to 1 (near black) for a total sample size of 370. Each of the 370 spectra was multiplied by the spectral radiant power distribution of D65 light so that the final results represent the spectra of reflected light from Munsell color chips under D65 illumination. We simultaneously model the structure of the color chips and the spectra in a common three-dimensional Euclidean space, oriented to yield the most interpretable structure with respect of the Munsell color structure. In this orientation, axis 1 roughly corresponds to the mean power of the spectral reflectance (approximate Munsell value), axis 2 goes from Munsell red to blue-green, and axis 3 goes from Munsell green-yellow to purple. Basis factors for the spectra are also plotted against wavelength and Munsell hue. These plots have implications for theories of opponent processes. By plotting the chips and spectra in the same space we obtain virtually exact correspondences between the various Munsell hues and spectral values in nanometers for comparison to those obtained by previous researchers. Mathematical derivations are provided to validate the common Euclidean model.},
keywords = {color, reflectance},
rating = {D}
}
-
Emanuel Todorov and Michael I. Jordan.
Optimal feedback control as a theory of motor coordination.
Nature neuroscience,
5:11,
2002.
Keywords: neuroscience,
motor control,
internal models,
feedback,
minimum variance.
| Abstract: Motor coordination the marshalling of redundant actuators in the service of a desired behavioral outcome is among the most important and least understood facets of motor function. Models that focus on mechanisms for achieving behavioral goals often fail to account for experimental data on movement variability and the exploitation of redundancy. Models that focus on variability and redundancy often fail to explain how goals are achieved in the first place. Here we show that not only are variability and goal achievement compatible, but indeed that allowing variability in redundant dimensions is the optimal strategy in the face of uncertainty. Our approach is based on stochastic optimal control theory, which provides, for a given task, the feedback control law that maximizes expected performance. This control law does not enforce a "desired trajectory" an approach that we show to be suboptimal but instead corrects only those deviations that interfere with the task goals. We find that the resulting behavior exhibits goal-directed adjustments, synergies, controlled parameters , simplifying rules , and discrete coordination modes none of which are built in a priori. Experimentally, we investigate a range of motor tasks and report patterns of variability in close agreement with the model. |
| Comments: un point très important: la variabilité des mouvements et la stabilité de la tache remplie. |
@Article{todo_jord_02,
author = {Todorov, Emanuel and Jordan, Michael I.},
title = {Optimal feedback control as a theory of motor coordination},
journal = {Nature neuroscience},
year = {2002},
volume = {5},
pages = {11},
keywords = {neuroscience, motor control, internal models, feedback, minimum variance},
rating = {B},
comments = {un point très important: la variabilité des mouvements et la stabilité de la tache remplie.},
abstract = {Motor coordination the marshalling of redundant actuators in the service of a desired behavioral outcome is among the most important and least understood facets of motor function. Models that focus on mechanisms for achieving behavioral goals often fail to account for experimental data on movement variability and the exploitation of redundancy. Models that focus on variability and redundancy often fail to explain how goals are achieved in the first place. Here we show that not only are variability and goal achievement compatible, but indeed that allowing variability in redundant dimensions is the optimal strategy in the face of uncertainty. Our approach is based on stochastic optimal control theory, which provides, for a given task, the feedback control law that maximizes expected performance. This control law does not enforce a "desired trajectory" an approach that we show to be suboptimal but instead corrects only those deviations that interfere with the task goals. We find that the resulting behavior exhibits goal-directed adjustments, synergies, controlled parameters , simplifying rules , and discrete coordination modes none of which are built in a priori. Experimentally, we investigate a range of motor tasks and report patterns of variability in close agreement with the model.},
url = {http://cogsci.ucsd.edu/~todorov/papers/coordination.pdf}
}
-
Yasuki Yamauchi,
David R. Williams,
David H. Brainard,
Austin Roorda,
Carroll Joseph,
Maureen Neitz,
Jay Neitz,
Jack B. Calderone,
and Gerald H. Jacobs.
What determines unique yellow, L/M cone ratio or visual experience ?.
9th Congress of the International Colour Association,
4421:275-278,
2002.
Keywords: color,
hues,
NCC.
| Abstract: Unique yellow is considered to represent the equilibrium point of the red-green opponent chromatic mechanism. There are several hypotheses that attempt to explain how this equilibrium point is established. The determinant for unique yellow, however, has not yet been clarified. Here we explored whether the L/M cone ratio or visual information determines unique yellow. If the former is the case, we expect that subjects with large differences in their L/M cone ratio would set different spectral lights to appear as unique yellow. The results of such an experiment, however, did not show a substantial difference in the value of unique yellow for two subjects with very different cone ratios. On the other hand, if the latter is the case, unique yellow should change when altering the chromaticity of the surrounding visual environment. To test this hypothesis, we conducted long-term adaptation experiments, in which subjects spent 8 to 12 hours in a chromatically altered environment. A significant shift of unique yellow was observed after spending time in such an environment for several days. These results indicate that the red-green opponent channel includes a plastic normalization mechanism that adjusts its balance point based on visual experience. |
| Comments: Il y a une large variabilité inter-personnes dans le rapport L/M (de 1 a 4), mais sans correlation avec la variabilié du unique yellow. Celui ci est par contre très dépendant de l'adaptation visuelle (lentilles teintées) |
@Article{yama_02,
author = {Yamauchi, Yasuki and Williams, David R. and Brainard, David H. and Roorda, Austin and Carroll Joseph, and Neitz, Maureen and Neitz, Jay and Calderone, Jack B. and Jacobs, Gerald H.},
title = {What determines unique yellow, L/M cone ratio or visual experience ?},
journal = {9th Congress of the International Colour Association},
year = {2002},
volume = {4421},
pages = {275-278},
abstract = {Unique yellow is considered to represent the equilibrium point of the red-green opponent chromatic mechanism. There are several hypotheses that attempt to explain how this equilibrium point is established. The determinant for unique yellow, however, has not yet been clarified. Here we explored whether the L/M cone ratio or visual information determines unique yellow. If the former is the case, we expect that subjects with large differences in their L/M cone ratio would set different spectral lights to appear as unique yellow. The results of such an experiment, however, did not show a substantial difference in the value of unique yellow for two subjects with very different cone ratios. On the other hand, if the latter is the case, unique yellow should change when altering the chromaticity of the surrounding visual environment. To test this hypothesis, we conducted long-term adaptation experiments, in which subjects spent 8 to 12 hours in a chromatically altered environment. A significant shift of unique yellow was observed after spending time in such an environment for several days. These results indicate that the red-green opponent channel includes a plastic normalization mechanism that adjusts its balance point based on visual experience.},
comments = {Il y a une large variabilité inter-personnes dans le rapport L/M (de 1 a 4), mais sans correlation avec la variabilié du unique yellow. Celui ci est par contre très dépendant de l'adaptation visuelle (lentilles teintées)},
keywords = {color, hues, NCC},
url = {http://color.psych.upenn.edu/brainard/papers/AIC01.pdf},
rating = {C}
}