Perceptual Inference Predicts Contextual Modulations of Sensory Responses

Another predictive coding paper (by Udo Ernst and others)

 

 

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Perceptual Inference Predicts Contextual Modulations of Sensory Responses

via Journal of Neuroscience current issue door Lochmann, T., Ernst, U. A., Deneve, S. op 21-3-12

Sensory receptive fields (RFs) vary as a function of stimulus properties and measurement methods. Previous stimuli or surrounding stimuli facilitate, suppress, or change the selectivity of sensory neurons' responses. Here, we propose that these spatiotemporal contextual dependencies are signatures of efficient perceptual inference and can be explained by a single neural mechanism, input targeted divisive inhibition. To respond both selectively and reliably, sensory neurons should behave as active predictors rather than passive filters. In particular, they should remove input they can predict ("explain away") from the synaptic inputs to all other neurons. This implies that RFs are constantly and dynamically reshaped by the spatial and temporal context, while the true selectivity of sensory neurons resides in their "predictive field." This approach motivates a reinvestigation of sensory representations and particularly the role and specificity of surround suppression and adaptation in sensory areas.

 

 

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Computer Vision online course

While some of you may be following Udacity courses on Python (I hear excellent comments about those), Berkeley is gonna offer soon ("Class starts March 2012") a Computer Vision course taught my Jitendra Malik whose work is both fantastic and relevant for us. I signed up!

There are even more high-quality courses offered, check the following:

- Udacity

- Coursera

- MITx

The difference between freely accessible content and Open Access

 

 

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The difference between freely accessible content and Open Access

via cognitive science and more door Sebastiaan Mathôt op 12-3-12

'Open access' is somewhat of a buzzword within academia. But unfortunately the term is widely misunderstood. All too often, the label 'open access' is used to refer to any content that can be accessed online for free. By this (incorrect) definition, most websites would be open access, because they offer content that you can read (or watch, listen to, etc.) for free. But you are usually not allowed to reproduce that content, or to sell it, modify it, etc. The only thing that you, as a consumer, are allowed to do is view the website right then and there, for as long as the owner of the website permits you.

This may be free of charge. It may even be a nice gesture. But it is not open access.

The definition of 'open access' is still evolving, but by consensus a number of conditions need to be satisfied for it to apply. In PLoS Biology, Michael Carroll gives us the following list:

Full open access content is

• Easily accessible online
• Available to anyone free of charge
• Available for re-use without restriction except that attribution be given to the source.

No one of these alone qualifies content for an open access label.

The paper by Carroll satisfies these criteria. I downloaded it for free. I am allowed to reproduce and redistribute the paper in it's entirety (here it is). And so are you. I didn't need Carroll's permission to upload his paper. And I do not (have to) care if he likes it. I just needed to provide attribution.

An open access license (such as CC BY) provides safeguards. Once a scientific paper is published under an open access license, it will be available to anyone, for ever (unless, of course, all copies get lost by some bizarre coincidence). Neither the author nor the publisher can undo this afterwards: The work is safe. In addition, open access publishing makes science accessible to the general public, which is invaluable. (Scientists are, after all, public servants.)

 

 

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open access at KU Leuven

Unfortunately, the new initiative for open access does not seem to
mean that the KU Leuven is now offering funds to publish papers in
open access journals.

http://www.kuleuven.be/onderzoek/open_access/index.html