Faster neural simulations with FPGAs

This paper describes the creation of a set of Matlab scripts that allow a researcher to efficiently program an FPGA to simulate a conductance-based neural network model. The researchers describe the use of their system to run a conductance-based model of 40 neurons with all-to-all connectivity at up to around 8x real-time (I wonder how long it takes to run the same model in software on a typical PC?).

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OpenViBE is an open source software environment “enclosing novel and efficient techniques for Brain-Computer Interfaces, Neurofeedback and Virtual Reality”. I haven’t downloaded and run it, but it looks like it takes EEG data and renders a 3D image of activity in your brain so that you can use this for neurofeedback. Could be fun in conjunction with the build-your-own-EEG projects that we mentioned recently here.

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Genetically altered mice can distinguish new colors

Gerald Jacobs, Gary Williams, Hugh Cahill, and Jeremy Nathans genetically engineered mice that have L-type cones. These mice could do a behavioral task that required them to distinguish two wavelengths of light that control mice couldn’t distinguish. This is amazing because it means that a brain architecture evolved to receive visual input from 2 types of cones can also usefully process information from 3 types of cones with no additional evolution.

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PFC lesion can change your ethical philosophy

A set of 6 subjects with bilateral damage to the ventromedial prefrontal cortex (VMPC) answered ethical questions in a way more consistent with utilitarian ethical philosophy than the control subjects. For example, they would be more willing to kill someone by pushing them off a bridge if that would save 5 other people. This supports the view that social emotions underly ethical judgments.

Michael Koenigs, Liane Young, Ralph Adolphs, Daniel Tranel, Fiery Cushman, Marc Hauser and Antonio Damasio.Damage to the prefrontal cortex increases utilitarian moral judgements. Nature. Published online 21 March 2007

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Amazing human neural plasticity

Echolocating kid, who had both his retinas surgically removed at an early age:

This dramatic example of human neural plasticity is amazing! Someone should go study this kid and his parents and find out more about how he developed his echolocation strategy. Are there other examples of this occurring in the medical literature? I’ve heard that blind people have very good hearing (and other senses) but this seems like a little more than “good hearing.” Also, thanks to Ben Huh for pointing me to this!

Multiple-color optical activation, silencing, and desynchronization of neural activity, with single-spike temporal resolution

As alluded to below in Neville’s post… here’s the link to the full paper, with a more complete description.

My lab, the Neuroengineering And Neuromedia Group at the MIT Media Lab, has just released a new neurotechnology. We found that just as the algal protein channelrhodopsin-2 (ChR2) can make neurons excitable by brief pulses of blue light, the mammalian codon-optimized version of the protein halorhodopsin (we abbreviate the mammalian codon-optimized form as Halo) can make neurons silenceable by brief pulses of yellow light. Furthermore, the activity of neurons expressing both Halo and ChR2 can be controlled bi-directionally by pulses of blue and yellow light respectively. This toolbox enables extremely sophisticated new kinds of experiment – such as being able to desynchronize neuronal spiking (without altering mean spike rate)! The paper just came out in PLoSONE, a new PLoS journal that encourages papers to become living documents — any reader can comment on any paper.

You can check out, and then comment on, the paper, “Multiple-color optical activation, silencing, and desynchronization of neural activity, with single-spike temporal resolution,” here.


Survival of the sickest

Saw this book on the Daily Show a few nights ago and it looked interesting: Survival of the Sickest by Sharon Moalem

book cover

The author mentioned a theory of schizophrenia as due to toxoplasma infected cats, who are themselves infected by rats carrying the disease. Apparently, when the rat is infected, the toxoplasma alters the behavior of the rat such that it doesn’t run away from a cat. So, the parasite ensures its survival.

Although I’m not a big fan of just-so evolutionary explanations in general, this book sounds like it might be a fun read.