-
O. Braddick,
J. Atkison,
B. Hood,
W. Harkness,
and G. J. Faraneh Vargha-Khadem.
Possible blindsight in infants lacking one cerebral hemisphere.
Nature,
360:461-463,
1994.
Keywords: blindsight,
neuroscience,
perception.
| Abstract: Patients with damage to the striate cortex have a subjectively blind region of the visual field, but may still be able to detect and localize targets within this region. But the relative roles in this 'blindsight' of subcortical neural systems, and of pathways to extra-striate visual areas, have been uncertain. Here we report results on two infants in whom one cerebral hemisphere, including both striate and extra-striate visual cortex, needed surgical removal in their first year. Single conspicuous targets in the half-field contralateral to the lesion could elicit fixations, implying detection and orienting by a subcortical system. In contrast, binocular optokinetic nystagmus (OKN), for which a subcortical pathway has often been thought adequate, showed a marked asymmetry. In normal neonates, fixation shifts and OKN have both been taken to reflect subcortical control; our results are consistent with subcortical control for fixation but not for OKN. |
@Article{brad_94,
author = {Braddick, O. and Atkison, J. and Hood, B. and Harkness, W. and Faraneh Vargha-Khadem, G. J.},
title = {Possible blindsight in infants lacking one cerebral hemisphere},
journal = {Nature},
year = {1994},
volume = {360},
pages = {461-463},
abstract = {Patients with damage to the striate cortex have a subjectively blind region of the visual field, but may still be able to detect and localize targets within this region. But the relative roles in this 'blindsight' of subcortical neural systems, and of pathways to extra-striate visual areas, have been uncertain. Here we report results on two infants in whom one cerebral hemisphere, including both striate and extra-striate visual cortex, needed surgical removal in their first year. Single conspicuous targets in the half-field contralateral to the lesion could elicit fixations, implying detection and orienting by a subcortical system. In contrast, binocular optokinetic nystagmus (OKN), for which a subcortical pathway has often been thought adequate, showed a marked asymmetry. In normal neonates, fixation shifts and OKN have both been taken to reflect subcortical control; our results are consistent with subcortical control for fixation but not for OKN.},
url = {http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=1448169&dopt=Abstract},
keywords = {blindsight, neuroscience, perception},
rating = {C}
}
-
R.A. Brooks and L.A. Stein.
Building Brains for Bodies.
Autonomous Robots,
1(1):pp. 7-25,
1994.
Keywords: embodiment,
artificial intelligence.
| Abstract: We describe a project to capitalize on newly available levels of computational resources in order to understand human cognition. We are building an integrated physical system including vision, sound input and output, and dextrous manipulation, all controlled by a continuously operating large scale parallel MIMD computer. The resulting system will learn to "think" by building on its bodily experiences to accomplish progressively more abstract tasks. Past experience suggests that in attempting to build such an integrated system we will have to fundamentally change the way artificial intelligence, cognitive science, linguistics, and philosophy think about the organization of intelligence. We expect to be able to better reconcile the theories that will be developed with current work in neuroscience. |
| Comments: Description d'un projet de développement d'une intelligence incarnée dans un robot, en contre-pied de l'approche objective : la cognition étant dépendante de l'expérience subjective serait elle même forcément subjective. Le papier est d'un enthousiasme débordant (littéralement), et l'on perd de vue l'argument. |
@ARTICLE{broo_stei_94,
AUTHOR = {Brooks, R.A. and L.A. Stein},
TITLE = {Building Brains for Bodies},
JOURNAL = {Autonomous Robots},
YEAR = {1994},
volume = {1},
number = {1},
pages = {pp. 7-25},
abstract = {We describe a project to capitalize on newly available levels of computational resources in order to understand human cognition. We are building an integrated physical system including vision, sound input and output, and dextrous manipulation, all controlled by a continuously operating large scale parallel MIMD computer. The resulting system will learn to "think" by building on its bodily experiences to accomplish progressively more abstract tasks. Past experience suggests that in attempting to build such an integrated system we will have to fundamentally change the way artificial intelligence, cognitive science, linguistics, and philosophy think about the organization of intelligence. We expect to be able to better reconcile the theories that will be developed with current work in neuroscience.},
comments = {Description d'un projet de développement d'une intelligence incarnée dans un robot, en contre-pied de l'approche objective : la cognition étant dépendante de l'expérience subjective serait elle même forcément subjective. Le papier est d'un enthousiasme débordant (littéralement), et l'on perd de vue l'argument.},
url = {http://www.ai.mit.edu/people/brooks/papers/brains.pdf},
rating = {B},
keywords = {embodiment, artificial intelligence}
}
-
Patricia Churchland.
Can Neurobiology teach us anything about consciousness ?.
Proceedings and Adresses of the American Philosophical Association,
1994.
Keywords: consciousness,
NCC.
| Abstract: Human nervous systems display an impressive roster of complex capacities, including the following: perceiving, learning and remembering, planning, deciding, performing actions, as well as the capacities to be awake, fall asleep, dream, pay attention, and be aware. Although neuroscience has advanced spectacularly in this century, we still do not understand in satisfying detail how any capacity in the list emerges from networks of neurons.[1] We do not completely understand how humans can be conscious, but neither do we understand how they can walk, run, climb trees or pole vault. Nor, when one stands back from it all, is awareness intrinsically more mysterious than motor control. Balanced against the disappointment that full understanding eludes us still, is cautious optimism, based chiefly on the nature of the progress behind us. For cognitive neuroscience has already passed well beyond what skeptical philosophers once considered possible, and continuing progress seems likely. |
@Article{chur_94,
author = {Churchland, Patricia},
title = {Can Neurobiology teach us anything about consciousness ?},
journal = {Proceedings and Adresses of the American Philosophical Association},
year = {1994},
url = {http://www.ecs.soton.ac.uk/~harnad/Papers/Py104/church.neuro.html},
rating = {C},
keywords = {consciousness, NCC},
abstract = {Human nervous systems display an impressive roster of complex capacities, including the following: perceiving, learning and remembering, planning, deciding, performing actions, as well as the capacities to be awake, fall asleep, dream, pay attention, and be aware. Although neuroscience has advanced spectacularly in this century, we still do not understand in satisfying detail how any capacity in the list emerges from networks of neurons.[1] We do not completely understand how humans can be conscious, but neither do we understand how they can walk, run, climb trees or pole vault. Nor, when one stands back from it all, is awareness intrinsically more mysterious than motor control. Balanced against the disappointment that full understanding eludes us still, is cautious optimism, based chiefly on the nature of the progress behind us. For cognitive neuroscience has already passed well beyond what skeptical philosophers once considered possible, and continuing progress seems likely.}
}
-
S. Illman.
Every proper smooth action of a Lie group is equivalent to a real analytic action: a contribution to Hilbert's fifth problem.
Prospects in topology,
138:189-220,
1994.
Keywords: mathematics,
geometry,
Lie groups.
@ARTICLE{illm_94,
author = {Illman, S.},
title = {Every proper smooth action of a Lie group is equivalent to a real analytic action: a contribution to Hilbert's fifth problem},
journal = {Prospects in topology},
year = {1994},
volume = {138},
pages = {189-220},
rating = {B},
keywords = {mathematics, geometry, Lie groups}
}
-
Geoffrey Iverson and Michael D'Zmura.
Criteria for color constancy in trichromatic bilinear models.
Journal of the Optical Society of America,
11(7):1970-1975,
1994.
Keywords: color constancy,
color constancy.
| Comments: Un classique sur le calcul des réflectances dans le cas où photorecepteurs, lumière et réflectances sont de dimension 3, à partir de plusieurs expositions d'une même scène. Etude quasi exhaustive. |
@Article{iver_dzmu_94,
author = {Iverson, Geoffrey and D'Zmura, Michael},
title = {Criteria for color constancy in trichromatic bilinear models},
journal = {Journal of the Optical Society of America},
year = {1994},
volume = {11},
number = {7},
pages = {1970-1975},
comments = {Un classique sur le calcul des réflectances dans le cas où photorecepteurs, lumière et réflectances sont de dimension 3, à partir de plusieurs expositions d'une même scène. Etude quasi exhaustive.},
keywords = {color constancy},
rating = {B},
keywords = {color constancy}
}
-
Zhaoping Li and Joseph J. Atick.
Towards a theory of the striate cortex.
Neural Computation,
6(1):127-146,
1994.
Keywords: vision,
neuroscience,
brain.
| Abstract: We explore the hypothesis that linear cortical neurons are concerned with building a particular type of representation of the visual world --- one which not only preserves the information and the efficiency achieved by the retina, but in addition preserves spatial relationships in the input --- both in the plane of vision and in the depth dimension. Focusing on the {\it linear} cortical cells, we classify all transforms having these properties. They are given by representations of the scaling and translation group, and turn out to be labeled by rational numbers `$(p+q)/p$' ($p, q$ integers). Any given $(p,q)$ predicts a set of receptive fields which come at different spatial locations and scales (sizes) with a bandwidth of $\log_2[(p+q)/p]$ octaves, and, most interestingly, with a diversity of `$q$' cell varieties. The bandwidth affects the trade-off between preservation of planar and depth relations, and, we think, should be selected to match structures in natural scenes. For bandwidths between $1$ and $2$ octaves, which are the ones we feel provide the best matching, we find for each scale a minimum of two distinct cell types that reside next to each other and in phase quadrature, i.e., differ by $90^o$ in the phases of their receptive fields, as are found in the cortex, they resemble the ``even-symmetric'' and ``odd-symmetric'' simple cells in special cases. An interesting consequence of the representations presented here is that the pattern of activation in the cells in response to a translation or scaling of an object remains the same but merely shifts its locus from one group of cells to another. This work also provides a new understanding of color coding changes from the retina to the cortex. |
@Article{li_atic_94,
author = {Li, Zhaoping and Atick, Joseph J.},
title = {Towards a theory of the striate cortex},
journal = {Neural Computation},
year = {1994},
volume = {6},
number = {1},
pages = {127-146},
abstract = {We explore the hypothesis that linear cortical neurons are concerned with building a particular type of representation of the visual world --- one which not only preserves the information and the efficiency achieved by the retina, but in addition preserves spatial relationships in the input --- both in the plane of vision and in the depth dimension. Focusing on the {\it linear} cortical cells, we classify all transforms having these properties. They are given by representations of the scaling and translation group, and turn out to be labeled by rational numbers `$(p+q)/p$' ($p, q$ integers). Any given $(p,q)$ predicts a set of receptive fields which come at different spatial locations and scales (sizes) with a bandwidth of $\log_2[(p+q)/p]$ octaves, and, most interestingly, with a diversity of `$q$' cell varieties. The bandwidth affects the trade-off between preservation of planar and depth relations, and, we think, should be selected to match structures in natural scenes. For bandwidths between $1$ and $2$ octaves, which are the ones we feel provide the best matching, we find for each scale a minimum of two distinct cell types that reside next to each other and in phase quadrature, i.e., differ by $90^o$ in the phases of their receptive fields, as are found in the cortex, they resemble the ``even-symmetric'' and ``odd-symmetric'' simple cells in special cases. An interesting consequence of the representations presented here is that the pattern of activation in the cells in response to a translation or scaling of an object remains the same but merely shifts its locus from one group of cells to another. This work also provides a new understanding of color coding changes from the retina to the cortex.},
comments = {à éclaircir},
url = {http://www.gatsby.ucl.ac.uk/~zhaoping/prints/Liatick94/scalewithfig.pdf},
rating = {C},
keywords = {vision, neuroscience, brain}
}
-
J-P Nadal and N Parga.
Non linear neurons in the low noise limit: a factorial code maximizes information transfer.
Network,
1994.
Keywords: ICA,
statistics,
neural networks,
information theory.
| Abstract: We investigate the consequences of maximizing information transfer in a simple neural network (one input layer, one output layer), focussing on the case of non linear transfer functions. We assume that both receptive fields (synaptic efficacies) and transfer functions can be adapted to the environment. The main result is that, for bounded and invertible transfer functions, in the case of a vanishing additive output noise, and no input noise, maximization of information (Linsker's infomax principle) leads to a factorial code - hence to the same solution as required by the redundancy reduction principle of Barlow, or, in the signal processing language, to Independent Component Analysis (ICA). We show also that this result is valid for linear, more generally unbounded, transfer functions, provided optimization is performed under an additive constraint, that is which can be written as a sum of terms, each one being specific to one output neuron. Finally we study the effect of a non zero input noise. We find that, at first order in the input noise, assumed to be small as compared to the - small - output noise, the above results are still valid, provided the output noise is uncorrelated from one neuron to the other. |
| Comments: Given idependant processings in different channels, it is when the signals on these channels are independant that the global mutual information between inputs and outputs is maximum. |
@Article{nada_parg,
author = {Nadal, J-P and Parga, N},
title = {Non linear neurons in the low noise limit: a factorial code maximizes information transfer},
journal = {Network},
year = {1994},
abstract = {We investigate the consequences of maximizing information transfer in a simple neural network (one input layer, one output layer), focussing on the case of non linear transfer functions. We assume that both receptive fields (synaptic efficacies) and transfer functions can be adapted to the environment. The main result is that, for bounded and invertible transfer functions, in the case of a vanishing additive output noise, and no input noise, maximization of information (Linsker's infomax principle) leads to a factorial code - hence to the same solution as required by the redundancy reduction principle of Barlow, or, in the signal processing language, to Independent Component Analysis (ICA). We show also that this result is valid for linear, more generally unbounded, transfer functions, provided optimization is performed under an additive constraint, that is which can be written as a sum of terms, each one being specific to one output neuron. Finally we study the effect of a non zero input noise. We find that, at first order in the input noise, assumed to be small as compared to the - small - output noise, the above results are still valid, provided the output noise is uncorrelated from one neuron to the other.},
comments = {Given idependant processings in different channels, it is when the signals on these channels are independant that the global mutual information between inputs and outputs is maximum.},
url = {http://citeseer.ist.psu.edu/nadal94non.html},
rating = {B},
keywords = {ICA, statistics, neural networks, information theory}
}
-
M. T. Wallace and B.E. Stein.
Cross-modal synthesis in the mid-brain depends on input from association cortex.
Journal of Neurophysiology,
71:429-432,
1994.
Keywords: sensory integration,
perception,
neuroscience.
| Abstract: The synthesis of information from different sensory modalities in the superior colliculus is an important precursor of attentive and orientation behavior. 2. This integration of multisensory information is critically dependent on inputs from a small area of association cortex, the anterior ectosylvian sulcus. Removal of these corticotectal influences can have a remarkably specific effect: it can eliminate multisensory integration in superior colliculus neurons while leaving their responses to unimodal cues intact. 3. Apparently, some of the associative functions of cortex are accomplished via its target neurons in the midbrain. |
@Article{wall_stein_94,
author = {Wallace, M. T. and Stein, B.E.},
title = {Cross-modal synthesis in the mid-brain depends on input from association cortex},
journal = {Journal of Neurophysiology},
year = {1994},
volume = {71},
pages = {429-432},
abstract = {The synthesis of information from different sensory modalities in the superior colliculus is an important precursor of attentive and orientation behavior. 2. This integration of multisensory information is critically dependent on inputs from a small area of association cortex, the anterior ectosylvian sulcus. Removal of these corticotectal influences can have a remarkably specific effect: it can eliminate multisensory integration in superior colliculus neurons while leaving their responses to unimodal cues intact. 3. Apparently, some of the associative functions of cortex are accomplished via its target neurons in the midbrain.},
url = {http://jn.physiology.org/cgi/content/abstract/71/1/429},
rating = {C},
keywords = {sensory integration, perception, neuroscience}
}