When an alarm isn't enough, try a dopamine agonist instead?

April 17th, 2010 in Uncategorized 0 comments

After a serious accident, victims can sustain grave injuries, such as severe traumatic brain injury (TBI), resulting in focal lesions and/or diffuse axonal injury. This can result in a coma that can develop into a Vegetative State (VS) or Minimally Conscious State (MCS), wherein the victim regains arousal, but with low awareness. Studies of these states suggest a deficiency in dopamine, a neurotransmitter involved with general stimulation, wakefulness, and circadian rhythms. Thus, to treat VS/MCS patients, dopamine agonists, such as l-dopa , bromocriptine, and amantadine, have been used. These agonists are plagued with issues, namely that they are either too weak (bromocriptine and amantadine) or may result in complications due to administration method (l-dopa). Thus, a group of researchers have recently tested apomorphine, which is potent and is a broadly acting dopamine agonist, to attempt treating VS/MCS. In fact, apomorphine is so potent, that it is the drug of last resort in Parkinson’s Disease (PD). The researchers continuously administered apomorphine subcutaneously (via pump) to a 25-year-old male patient for 12 hours a day (followed by 12 hours of rest period) over 179 days. They saw results as early as the first day, when the patient was able to move his limbs on command and answer yes/no questions (which did not happen preceding treatment). Following this, their patient even made a full recovery of consciousness and regained substantial functional ability. This regain of consciousness and function continued pas discontinuation of treatment. Though there were side effects in the form of dyskinesias at high doses, the treatment resulted in remarkable recovery at lower doses. Using Diffusion Tensor Imaging (DTI), an MRI technique, the researchers found a decrease of thalamocortical and corticothalamic projections (compared to the control). It may be that VS/MCS is a result of thalamocortical and corticothalamic dopaminergic deficiencies, which can be a treated quite easily with apomorphine. If it is a universal cause of VS/MCS in trauma victims, we may soon expect apomorphine widely used to revive comatose patients.

Fridman EA, Krimchansky BZ, Bonetto M, Galperin T, Gamzu ER, Leiguarda RC, et al. Continuous subcutaneous apomorphine for severe disorders of consciousness after traumatic brain injury. Brain injury : [BI]. 2010;24(4):636-41

-Neil Datta

“Memristors” to replace your neurons? Thanks, but no thanks.

April 13th, 2010 in Uncategorized 1 comment

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Researchers at the Hewlett-Packard laboratories in California have produced tiny electronic switches called memristors (shortening of memory-resistor) that have the potential to revolutionize computing.

Traditional electronic devices use small switches called transistors as the elements of information storage and transfer. A typical computer may have millions of transistors, which may be on the scale of tens of nanometers. Limits in possible reduction of transistor size serve a great threat to progress in integrated circuit design. Memristors – about 3 nanometers in length – therefore offer a new path for making smaller and denser electronic devices.

The team’s report in last week’s issue of Nature shows off the data, with electric traces that are hauntingly reminiscent of neuronal current-voltage plots and action potentials.

The New York Times quotes Dr. Chua, who envisaged memristors in 1971, as saying that “our brains are made of memristors… We have the right stuff now to build real brains.” But are these inglorious transistors really capable of mimicking biological brains?

Simply thinking of the scale differences suggests that the answer may be… maybe. A neuron cell body is on the order of 10-25 micrometers. Compare that to the 3 nanometers of the memristor. Furthermore, memristors operate on a time scale of nanoseconds, whereas most neurons are much slower, spiking in milliseconds.

So memristors are smaller and faster than neurons. In fact, current transistors are also smaller and faster than neurons. So why haven’t computers taken over the world? For one, computers are designed to do what we tell them. And even maverick computers (if they exist) aren’t nearly as smart as the average human. This is because information is transferred in parallel in the brain; and in series in the computer. Put simply: the brain does many things simultaneously, even if slowly, while the computer does only one thing at a time, very quickly. (Curious readers should see “The computer and the brain” by John Von Neumann).

So while memristors may be found inside your next nano-MacBook or iPod-atomic, don’t expect them to replace your neurons.

ORIGINAL NATURE PAPER: http://www.nature.com/nature/journal/v464/n7290/full/nature08940.html#B15

NY TIMES ARTICLE: http://www.nytimes.com/2010/04/08/science/08chips.html?ref=science

– G. Guitchounts

Stressed? It may be in your genes…

April 11th, 2010 in Uncategorized 0 comments

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With finals around the corner, the stress factor on campus is bound to rise in the next few weeks. Individual students have their own way of coping with stress, such as TV, video games, music, power naps at Mugar Library (the cubbies are quite comfortable) or a marathon visit to FitRec. Regardless of the method, all aim to reduce the anxiety of coming exams.

Stress also has a neurophysiological effect that decreases rates of neuroplasticity (the ability for the brain to “rewire” itself) in the hippocampus – an area believed to be a center of learning and memory. Additionally, new research suggests that there is a genetic basis for stress effects on the brain connected to a protein called brain derived neurotrophic factor (BDNF). In a joint study conducted by Rockefeller University and Weill Cornell Medical College researchers, it was found that mice with inadequate BDNF expression had brains that looked similar to those of mice exposed to chronic stress over a long period of time. These mice were not exposed to chronic stress, yet they still showed decreased rates of neuroplasticity in the hippocampus – a characteristic of stressed brains.

It seems that stress is a product of our environment as well as our genes. At this point, research on BDNF is just beginning. However, this research might open doors to the treatment of chronic stress disorders on the genetic and physiological level without the use of controversial psychotropic drugs.

Read the full article over at Science Daily for the whole scoop.

Gene That Changes the Brain’s Response to Stress Identified

via Science Daily

Diplomacy Robots soon to be in production!

April 1st, 2010 in Uncategorized 0 comments

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Engineers at Frankfuter Univeristy, Germany have joined with a team of  American neuroscientists to  create  robots “capable of facilitating peaceful negotiations even in the most tension filled of atmospheres.” These robots were designed to mimic behaviors that humans “find irresistibly attractive and calming” in order to diffuse anger and pave  the wave for fruitful exchange.  Videos of the robots learning the desired patterns of behavior can be found at:

Diplomacy Robots at Work