Fenris Friday

Neurobots: Robots Controlled by Brain Simulations

Simulations

Researchers have been developing robots that are powered by better artificial brains. They have recently created a computer neural simulation consisting of 6,700 neurons with approximately 1.3 million synaptic connections. This technology builds on previous work in the field of neurorobotics. The robot they used for this experiment is shown on the left. It is equipped with a CCD video camera. The camera has IR sensors to avoid obstacles and an RF transmitter to process objects visually. The emulation attempts to model aspects of the mind that researchers believe to be important for information processing. The goal is to allow the robot to act in a manner similar to an actual animal. This gives insight into the functioning of the brain and how it encodes for behavior.

The scientists claim to have chosen three different neurotransmitters subsystems to model. These systems include dopamine, acetylcholine and serotonin. Dopaminergic, cholinergic and serotonergic cell bodies are found in the VTA, basal forebrain and raphe nucleus respectively. Some of these cells are located deep within the brain and they project their axons like a branching tree to numerous other regions. The synaptic junctions allow cross-talk between areas using these discrete neurotransmitters as messengers.

The VTA for instance (see picture on left), makes connections to places like the nucleus accumbens and prefrontal cortex. The neural facsimile they carried out emulates 100 neurons for each of these three cell body regions. Their simulation also contains brain cells devoted to processing images from the CCD camera. In addition, they have areas to encode for find/flee behavior and good/bad judgements (100 neurons for each).

So this is really an extremely simplified replica that is merely meant to represent some very basic ways that the researchers believe how the mind works. Obviously 6,700 neurons is much less complex than even a fly's brain. They ignored a considerable amount of neuronal function. So the behavioral output of this robotic device is definitely limited in scope compared to more complicated organisms.

The researchers appear to give an overly simplistic explanation for how specific neurotransmitter systems function. So I'm not necessarily convinced of the utility in labeling the 100 neuron subpopulations as "dopaminergic" or "serotonergic". Their brain is really only a crude simulacrum and assigning these labels may not be particularly relevant.

Dopamine appears to be important for “wanting”, that is, the motivation process in acquiring an object [13]. Dopamine, which is found throughout the central nervous system, is produced in the ventral tegmental area. A recent proposal ties the prediction error to wanting by suggesting that incentive salience is the expected future reward that maps actions to rewards [14].

There are a lot of nuances to dopamine's role in motivating an organisms to action and I'm not confident that the authors do it justice in their paper. Since this is done via computer, it does allow the scientists to do temporary lesions to see the resulting affect on robotic performances. They can basically turn off the functioning of specific neurotransmitter subsystems selectively. I'd be wary, though, of linking the behavioral changes that they witnessed to a real animal's dopaminergic system.

When CARL-1’s dopaminergic system was intact, it approached stimuli that were predictive of positive value, and ignored neutral stimuli. When CARL-1’s VTA was lesioned, the number of Find responses, which signify “wanting”, significantly decreased. Instead of approaching these positive-value stimuli, CARL-1 treated green objects as neutral stimuli.

They go on to talk about the other neuromodulatory systems and how adjusting them altered the functioning of the neurobot.

In our experiments with CARL-1, we showed that serotonergic neuromodulation arising from a simulated Raphe nucleus was needed to respond appropriately to threatening stimuli. When CARL-1’s serotonergic system was intact, it moved away from threatening stimuli, and ignored neutral stimuli.

The interpretations they make seem somewhat facile to me. However, I do think the interesting aspect of neurorobotics is that it allows the researchers to test an extraordinary range of different hypotheses. There is a lot of potential in scaling up the neuron count to enable a more extensive range of robot routines.

You can see some videos of this robot here. A recent paper on the topic is here (PDF). The researcher also gave a video presentation about it (see here, requires flash).

GPU Conference Presentations

I mentioned previously about a GPU conference that discussed the implications of the technology for doing scientific research. There are certain classes of problems that GPU's are especially suited for and they offer a speed up when compared to CPU's. As an example, researchers have recently developed a relatively inexpensive 13 gpu "supercomputer" with about 12 teraflops of computing power for scientific problems. GPU's have been rivaling the complexity of intel's most advanced technology and 3 billion transistor gpu chips will probably hit the market shortly. Nvidia also believes that they can reach 10 billion transistors easily. With this speed up of processing power coupled with machine learning, we will be able to learn more about the brain than ever before. While it's probably somewhat facile to make a blanket statement that computing power is increasing exponentially, there are still some interesting exponential trends in the field that will likely continue for at least the next 5 or ten years.

Nvidia has put media from that 2009 conference online and several of them are related to neuroscience. The company Evolved Machines is "pioneering the reverse engineering of brain circuitry to build intelligent machines". An audio talk can be found here (6.1 MB).

"Reconstructing the Brain: Extracting Neural Circuitry with CUDA and MPI" is a 37.6 MB video presentation (download here). The following is an excerpt about that video;

In this talk we will present our insights and lessons learned in using CUDA to reconstruct neural connections in high-resolution EM data. We will present technical details and non-trivial issues regarding the implementation of NeuroTrace, our system for semi-automatic segmentation and interactive visualization of terabytes of EM image data. The segmentation method is based on a sequence of 2D level set segmentations of cell membranes integrated with an image correspondence energy for robust transition between consecutive slices and a weighted path extrapolation method to trace a 3D centerline of a neural pathway along non-axis aligned slices.

Optimizing Ion Channel Kinetics Using A Massively Parallel Genetic Algorithm on the GPU (26.4 MB video presentation);

Voltage-gated ion channels effect the integration of information in many neurons. Some neurons express over 10 voltage-gated channels that turn information processing into a highly non-linear affair.

The currently popular analysis techniques suffer from various shortcomings that limit the ability of the researcher to rapidly produce physiologically relevant models of voltage-gated ion channels.

To solve this computational bottleneck we have been converting our optimization algorithm to work on a GPU using CUDA. We have succeeded to parallelize the process on a GTX 295 giving a speed increase of roughly X100 over that of the CPU.

Medical Image Registration with CUDA (37.6 MB video presentation);

Speedups of up to 750 times were obtained as compared to code in daily use at Addenbrookes Hospital and Bio-Medical Campus. Some very recent results are shown in the figures. This work is of direct application in both research and clinical practice. A particular application is voxel based MRI morphometry in humans and in animal brains.

High-Throughput Science (271 MB keynote speech);

How did the universe start? How is the brain wired? How does matter interact at the quantum level? These are some of the great scientific challenges of our times, and answering them requires bigger scientific instruments, increasingly precise imaging equipment and ever-more complex computer simulations.

The rest of the presentations can be found here. They cover a wide variety of topics.

Anima Morte - Face The Sea Of Darkness (2007)

Here's something quite different for a change; Anima Morte or "vintage Italian horror music from Sweden".This band brings us back to the good old days where horror had weird, proggy, unique & memorable soundtracks.

This is a highly atmospheric, eerie & a refreshing take on the usual tunes. Even if you don't know a thing about Italian horror (and it's soundtracks), you should give it a listen. This is enthralling prog-instrumental music with an incredible atmosphere. Another underground gem that cannot be missed!

animamorte.com
myspace.com/animamorte

Physical needs: Transubstans records

MP3@320Kbps
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Scans
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Kosmograd - Kosmograd (2011)

Unique post-sludge with proggy & psychedelic elements. What I love about 'Kosmograd' is the raw yet thick production & the highly instrumental focus (think Omega Massif, Russian Circles, Jakob, Pelican,..). Quite a surprise when the vocals kick in on the second track. Not exactly my cup of tea after the fantastic opener, but it's executed with the right moderation in the layered & dynamic sound this band has to offer. Another highly recommended (free) Bandcamp release!

"Toronto post-metal band creates the perfect winter music, moving at the pace of a snow drift, crushing heaviness & girth pull themselves forward. Slow distortion blistered guitar riffs, crackle and break through walls of cymbal hits, as they form their own wall of drone that washes over everything only easing up as we reach the calm in the storm., Quiet post-rock guitar artistry, builds on itself free of the chains & weight of distortion. Building back into the distortion laden caustic metal guitar jabs, the band lurches forward again, gaining speed & hardcore vocal intensity. "

kosmograd.bandcamp.com
onesheet.com/kosmograd

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Litmus - You Are Here (2004)

Litmus is a London-based space rock band formed in 2000. In terms of the blog: the perfect blend between the intergalactic instrumentals of bands like Secret Saucer & Oresund Space Collective and the furious space rockin' vibes of Farflung & Astrosoniq. Ofcourse, Hawkwind & Black Sabbath are the key influences here. Still, Litmus is quite unique in it's own way, creating spacy hard rock with an edge, a sharp edge. It's heavy, distorted, hypnotic, psychedelic, spaced out. Grab this, get in your mothership & turn it up...

myspace.com/litmusspacerock

Physical needs: Amazon

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Zozobra - Bird Of Prey (2008)

Latest album, featuring Aaron Harris of Isis on drums.

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*new reposts
Dozer - Madre De Dios; Call It Conspiracy (320Kbps)
Grand Magus - Iron Will (320Kbps)