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The Institute for Ethics and Emerging Technologies alterted me to an interesting new online magazine put out by the Rathenau Institute. The Rathenau institute is an independent organization from the Netherlands that deals basically with future science/technology and its impact on society. You can download the magazine for free here (pdf file) (or try here if that doesn't work). It talks about some issues dealing with the brain and neurotechnology. Here's a short quote from it.
In the Human Enhancement Dossier, Flux lists the harbingers of a glorious new world full of high-performance bodies and brains. In ?The lure of human enhancement?, the authors argue that as a result of developments in nano, bio, info and cognitive technology, human enhancement is no longer science fiction. The British author Nikolas Rose contends that new biomedical technology is not only bringing about a change in our relationship with our own bodies, but also a change on the political scene.
Various technologies to improve our bodies and our life emerging from the fields of pharmacology, the neurosciences, biotechnology and man-machine interactions are being developed in laboratories. But they are also reaching different domains of application already. Contemporary societies adopt and transform technological innovations at an enormous speed. Today?s scientific developments may reach the market and the consumer by tomorrow. As a consequence, human enhancement is rapidly becoming a societal issue. Existential questions and their scientific exploration are now reaching the public.
I've always been a big fan of future science and science fiction, so this type of stuff is right up my alley. There is also the H+ online magazine (PDF) that came out a little while ago that covers similar topics.
NeuroNexus Technologies and Philips are teaming up to create smaller and more responsive deep brain stimulation devices. These devices will also be MRI friendly. Neuronexus has some experience in creating polymer and silicon based micro-electro-mechanical systems (MEMS). Better deep brain stimulation devices will likely last longer in the brain and interface better with the surrounding brain tissue. Future deep brain stimulation devices will continue to miniaturize as time goes forward. Here's the press release.
By combining Philips Research?s strengths in microelectronics, signal processing, ultra-low power system design and miniaturization with NeuroNexus Technologies? expertise in micro-scale electrode design and fabrication, the two companies aim to show the technical feasibility of highly programmable and MRI-safe deep brain stimulation devices. Their initial research will aim to meet the functional requirements of a deep brain stimulation device for the treatment of Parkinson?s disease. This is a degenerative disorder of the central nervous system that impairs people?s motor skills and speech, leading to a progressive loss in quality of life. Recent publications suggest that deep brain stimulation could also be suitable for treating psychiatric disorders such as clinical depression.
Carbon nanotubes are composed of carbon atoms arranged in a honeycomb pattern bended in a round tube shape. They are only a few nanometers in size, about 1/50,000th of the width of a human hair. Carbon nanotubes have a variety of interesting properties and are conductors of electricity. Research from a year ago demonstrated that neurons grown on carbon nanotubes had increased electrical activity. Surprisingly neurons can grow very well on these carbon nanotubes. Devices based on carbon nanotubes may lead to better deep brain stimulation implants or brain computer interfaces.
Recently researchers have found that the increased activity of the neurons on the carbon nanotubes results partly from electrical signals propogating through the carbon nanotubes themselves. The researchers used hippocampus brain cells attached to a fullerene nanotube. At the level of a neuron, there are a variety of constraints to the processing of neural information. These constraints include the time it takes for neurotransmitters to diffuse across the synaptic cleft and the speed of electrochemical signals down the axons and dendrites of the neurons. The electrochemical signals that move down the axon of a neuron are much slower than electricity moving through a carbon nanotube. According to one researcher "This kind of substrate can actually work as a kind of shortcut between two points of a network of neurons, or two points of the same cell". The team that is performing this research wants to use it to help those with spinal cord injuries. Other researchers have indicated that carbon nanotubes could potentially have some negative effects on neuron excitability as well depending on specific factors.
Could carbon nanotubes allow researchers to vastly accelerate the brain's processing speed and drastically alter our perception of time? Could interneuronal connections be replaced or enhanced with carbon nanotube junctions? At this point probably not. Neurons can only fire at a specific rates and these types of connections probably wouldn't change that. Without some massive reengineering of the brain it would probably either completely mess up the brain's dynamics or just add noise to the brain's computational capacity depending on the extent of added nanotubes. There would not be a subsequent increase in brain processing speed. A lot of the brain's processes are emergent phenomenon that depend on the brain's massive parrallelism. The additive effects of trillions of slow interneuronal connections create a unitary conscious experience with a difficult to quantify overall brain processing speed construct. Arbitrarly speeding up connections at one "level" (atomic level) of brain activity is no guarantee that you would beneficially alter higher "levels" of activity (aggregate neuron firing rates). Whole brain processing speed is probably due to additive effects at a variety of brain "levels".
Carbon nanotubes as scoffolding, though, may enable researchers to repair specific tissue damage with stem cell synthesized brain matter. Or the nanotubes could serve as a replacement junction connection for single neurons. Brain implants based on carbon nanotubes could treat a variety of brain disorders. Perhaps in the future we will have more sophisticated brain computer interfaces that will make full use of the transmission speed and the computational capacity of carbon nanotubes.
The US government's Defense Advanced Research Projects Agency (DARPA) has given a 4.9 million dollar grant to I.B.M. research and five universities for a new project. They basically want to reverse engineer the brain on a neuromorphic chip. I have mentioned about DARPA doing this in the past. However, then the deal was not yet finalized. You can read about the contract at DARPA's website. At the I.B.M. Almaden Research Center, Dharmendra Modha is now currently the manager of cognitive computing. You can read more information about this project at Modha's blog. Modha?s team has already been trying to reverse engineer the human brain. Modha estimates that by 2018 we will have the capability to simulate the entire human brain in real time on a computer. Modha?s group has already published a paper about simulating a rat brain in real time.
The human cortex has about 22 billion neurons which is roughly a factor of 400 larger than our rat-scale model which has 55 million neurons. We used a BlueGene/L with 92 TF and 8 TB to carry out rat-scale simulations in near real-time [one tenth speed]. So, by naïve extrapolation, one would require at least a machine with a computation capacity of 36.8 PF and a memory capacity of 3.2 PB. Furthermore, assuming that there are 8,000 synapses per neuron, that neurons fire at an average rate of 1 Hz, and that each spike message can be communicated in, say, 66 Bytes. One would need an aggregate communication bandwidth of ~ 2 PBps.
Modha also believes that nanotechnology will enable researchers to develop and replicate at the nano-scale the structure of a real human brain. Modha recently gave a talk at the 2008 singularity summit.
Here's an excerpt from the IBM press release about this new project.
IBM and its collaborators have been awarded $4.9 million in funding from the Defense Advanced Research Projects Agency (DARPA) for the first phase of DARPA?s Systems of Neuromorphic Adaptive Plastic Scalable Electronics (SyNAPSE) initiative. IBM?s proposal, ?Cognitive Computing via Synaptronics and Supercomputing (C2S2),? outlines groundbreaking research over the next nine months in areas including synaptronics, material science, neuromorphic circuitry, supercomputing simulations and virtual environments. Initial research will focus on demonstrating nanoscale, low power synapse-like devices and on uncovering the functional microcircuits of the brain. The long-term mission of C2S2 is to demonstrate low-power, compact cognitive computers that approach mammalian-scale intelligence.
Its still too early to say how much this research will actually accomplish. I suspect we may be able to simulate some of the processes of the brain relatively well. However, I think it may be fairly difficult to get that brain to be conscious. If we do successfully replicate consciousness it brings up all sorts of ethical issues, like how ethical is it to make a conscious human brain replica?
There are a variety of ways of going about creating a brain. This could include computer brain simulations (see here and here), neuromorphic chips or even possibly using stem cells to synthesize whole brain tissue. I think eventually we will be able to replicate a brain fairly well. If not on a computer or neuromorphic chip, then definitely using actual neurons possibly created from stem cells. Sufficiently advanced nanotechnology should allow the precise placement of neurons, dendrites and synapses. With sophisticated brain imaging techniques, this could allow scientists to create an exact replica of someone's brain.
Parkinson's disease is a fairly devastating illness. Dopaminergic brain cells die off over the course of this brain disorder. As brain dopamine levels fall, patients often have increasing difficult moving. They may show signs of tremor, muscle rigidity, a slowing of physical movement and sometimes a complete loss of physical movement. Patients become increasingly trapped in a body that ceases to function normally. There are a variety of drugs that are used to artificially increase the neurotransmitter dopamine in the brain. These drugs include dopamine agonists, dopamine precursors and drugs that inhibit the breakdown or reuptake of dopamine. In the future, successful treatment of parkinson's disease will need to be able to slow down the death of dopaminergic brain cells that synthesize dopamine and not just replace the missing dopamine. Doing this would allow a patient to retain their functioning without a large decline.
Now researchers at the Mayo Clinic are testing RNA interference to reduce the alpha-synuclein protein in the brain. Too much of the alpha-synuclein protein can accumulate in certain parkinson's patients and this is believed to be the cause of some of the brain cell death in these people. RNA interference is a way of selectively knocking down the functioning of a specific gene. It can selectively reduce the amount of protein being synthesized by that gene by introducing a short RNA strand. In a recent study, scientists infused small interfering RNA's into the brains of mice. They found that the RNA Interference was able to silence the alpha-synuclein gene and reduce the production of the alpha-synuclein protein for approximately 3 weeks.
There are quite a few problems with RNA interference. Problems include making sure that the RNA interference knocks down the correct gene and doesn't target any other genes. Also it is difficult to find a proper delivery mechanism for the RNA interference. RNA strands can easily be degraded in the body. Scientists have really been working hard at getting RNA interference to work for many disorders. However, it is currently not clear if they will be able to overcome these hurdles to get RNA interference to be used in real patients. Researchers have recently created oral pills that can deliver RNA interference. So RNA interference may eventually be used for certain brain disorders where knock down of a specific protein is necessary.
A majority of hallucinations found in people who have schizophrenia are auditory in nature. Schizophrenics may hear voices that do not exist in reality. They can sometimes make disparging commentary towards the person and can be very distressing. The amount of patients that hear auditory hallucinations are in the range of 50 to 70 percent of schizophrenics. For auditory hallucinations, the left temporoparietal cortex has been show to have increased activity. Transcranial magnetic stimulation has been used to reduce activity in that area of the brain. By selectively reducing activity here, scientists are able to reduce the amount of non real voices a person hears.
Other types of hallucinations outside the range of auditory (visual, sensory) are much rarer. You can read an interesting case study about using transcranial magnetic stimulation to reduce coenesthetic hallucinations in a single patient here. The coensthetic hallucinations consisted of having a feeling of undergoing electric shocks and also a feeling of having alien objectsmoving inside the person's pelvis/thorax/abdomen. These would definitely be very disturbing and troubling hallucinations to have to endure. They are possibly much more frightening than regular auditory hallucinations.
The patient actually benefited from 10 daily sessions of fMRI guided low frequency transcranial magnetic stimulation. They directed the TMS pulse over a brain area called the somatosensory cortex to reduce neuron activity their. This person had previously been treatment resistant to anti-psychotic therapy. The authors of the paper linked overactivation in the somatosensory cortex to the type of sensory hallucination that the person was experiencing.
I think this shows that TMS has a pretty good selectivity and scientists may be able to treat many currently treatment resistant patients. Brain areas can be selectively targeted for deactivation/activation as I have mentioned in the past. Better characterization of the changes induced by TMS by using real time brain imaging should help obtain even better responses.
Blog Directory ID: 2494
Blog URL: http://brainstimulant.blogspot.com
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Blog Description: Blog covering several topics about the brain, neuroscience and neurotechnology
Blog Tags: Neuroscience - Science - Technology 
Blog Category: Technology Blogs
Blog Owner: Michael Webb
Blog Added: May 06, 2008 05:48:57 PM
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