I recently blogged and vlogged about Medtronic starting a clinical trial where deep brain stimulation (DBS) would be applied to the ventral striatum (part of the human reward circuit) to treat depression in up to 200 patients. Then the article on CNNmoney that I was basing this on disappeared and I worried that the whole thing might have been a mistake or a hoax. But the article has resurfaced on the Wall Street Journal and elsewhere, and I finally got around to digging up Medtronic's original press release from 19 Feb 2009, which confirms that they are conducting a clinical trial of DBS as a treatment for depression.
But more than that. It turns out that the entire implant procedure that they're using isn't new at all - it's the same procedure they use to treat OCD (recently FDA approved for up to 4000 patients). The implant is called Reclaim and (quoting the press release) "the anatomical target in the brain is the.. ventral striatum.. which is a central node in the neural circuits believed to regulate mood and anxiety". So it seems DBS implants have been placed in the human reward circuit since the OCD trials started, many years ago. This is good news because it means we're even better at putting DBS implants in the human reward circuit than I thought we were. Basically, DBS applied to the ventral striatum (VS) didn't just alleviate the behavioural tics of OCD patients but also improved their mood. Studies like Schlaepfer et al 2008 (3 patients) and Malone et al 2009 (15 patients), which I thought were ground-breaking, merely confirmed that DBS applied to the VS improves the mood of severely depressed patients as well.
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The baby boomers are getting older. Their pensions and healthcare will exert an enormous strain on European, north American, East Asian and Australian economies over the next few decades. Advances in medicine and medical technology continue to reduce blood-pressures, patch up hearts, extract cancers and extend life expectancy worldwide, but the brain, it turns out, does not yield to traditional methods, and effective treatments for cognitive decline and neurodegenerative diseases like Alzheimer’s remain elusive. In the US, the annual cost of care for sufferers of Alzheimer’s is expected to exceed the total current healthcare budget ($1 trillion) as 10 million baby boomers develop the disease (Nixon et al, 2008 , Alzheimer’s Association, 2008).
There is, however, one highly effective preventive treatment: heavy physical exercise cuts one’s risk of stroke and neurodegenerative disease in half (Medina, 2008). Heavy, regular physical exercise improves blood supply to the brain, eliminates free radicals and stimulates the generation of new neurons. In the coming decades, 500 billion dollars or more could thus be saved each year in the US alone if every baby boomer exercised daily. The problem of course is that exercise is difficult and people are sedentary, so sedentary in fact that we are faced with a looming obesity epidemic that compounds the problem of age-related cognitive decline. And there’s no way of using modern medicine to improve people’s motivation to engage in physical exercise, right?
Wrong. A technique called rewarding brain stimulation has for decades allowed researchers to motivate rats to run (Burgess et al, 1991), lift weights (Garner et al, 1991) and learn other behaviours (Hermer-Vasquez et al, 2005).
Here’s how it might work in people: A person needing help to exercise would go to a hospital or a private clinic to be fitted with a deep brain stimulation implant capable of activating his reward system (the dopamine system).
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To Mr Barack Obama, the next president of the
United States of America (who did not make use of a recent
opportunity to discuss science in public) 
and President Hu Jintao of the People’s
Republic of China (a trained engineer who will without doubt
realize the potential of this technology)
Dear Sirs,
As the two who will be most personally responsible for the world
in the coming years, I wish to ask your advice on the following
issue. We are approaching a local singularity at the emergence of
the following technology:
What is an iPlant?
2min, YouTube
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I’ll run an iPlant seminar at the University of Sussex in May.
The powerpoint presentation (currently nowhere near finished)
can be found in the files section on
the forum. Please have a look at it from time to time and let me
know what you think.
Deep brain
stimulation (DBS) is a surgical procedure involving the
insertion of a small electrode into the brain to modulate
electrical activity. Over 40.000 patients worldwide have undergone
placement of Medtronic Activa,
the most popular DBS system (Schwalb
& Hamani, 2008).
The connectivity of cortical and subcortical brain tissue is
often too intricate to parse information from a single DBS electrode. Generation of meaningful visual
perception by stimulation of the visual cortex for example requires
a large number of much smaller electrodes (Schmidt
et al, 1996). DBS is therefore used
merely to suppress or normalise electrical activity in
dysfunctional brain regions (hence the nickname ‘brain
pacemaker‘).
However, many monoaminergic neurons in the midbrain and
brainstem fire in unison and project widely throughout the brain:
by stimulating neurons that produce dopamine for instance,
researchers can directly modulate dopamine concentrations in
diverse cortical and subcortical regions (Hernandez
et al, 2006
Garris et al, 1997
Fiorino et al, 1993
Bean & Roth, 1991). Stimulation of dopaminergic neurons,
serotonergic neurons or the nerve bundles that carry their axons to
cortical and subcortical targets is highly rewarding and is
referred to as brain
stimulation reward (BSR) in the literature.
(cont.)
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In response to the iPlant video,
richardpinder and
cromwell1646 write
the following (my emphasis):
richardpinder I can
see where you are coming from with this technology with regards to
taking it in a positive direction. However I think that this
science is far too dangerous, more so than every
other science I have knowledge of to be allowed public. The massive
risks of this technology is that it can lead to complete
mind control. Anything can be hacked given time thus it
wont be possible to make this hack proof. This technology can be
used to control free will and should be banned now. I hope you
fail.
cromwell1646 Dear
Sir, I have just watched your video on your iPlant. I think you are
coming at a problem from a positive direction. However this
technology could be easily and seriously
abused.
I am a programmer and I can tell you categorically its possible
to hack into anything given enough time. The implications of this
technology is it could be used to control someones
mind against their will in the wrong hands.
This means that the cult-like problems of today and people being
bent to do something extremely negative against their will pales
into insignificance compared to what this could do.
To spell it out this could be used in countries ruled by a
dictator to control its people. It could be used by Religious
extreme groups to make the perfect suicide bomber. It could be used
by criminal organisations to commit crimes.
(cont.)
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I sometimes feel that scientists have lost touch with the
profound and the sublime, whereas transhumanists and philosophers
have lost touch with science – with utility. Hume saw that
causality cannot be articulated (Hume,
1739,
1748) ; he did not say it should therefore be reduced to a
topic of rationalization and used only to cultivate one’s social
loci.
What happens when neruoscience dissolves the distinction between
mind and body? What happens when the intimate, subjective and
irrational human mind is fully integrated into the logic of
science, and a stable, effective and lucid, yet decidedly
neuroscientific model (M1) of the mind is realized? Eliminativists
speak about the end of our common-sense understanding of the mind,
but offer only vague speculations as to what might replace it
(Churchland,
1981). Is this a technological singularity – a point in history
so complex and fast-moving that we cannot see beyond it?
The iPlant can be used as an intellectual probe, to model and
better characterize the social impact of M1. A critical aspect of
scientific models is that they allow us to improve on the systems
that they describes. The iPlant helps us improve on the
strongest current candidate for M1: the cognitive neuroscience
of monoamines, particularly the
dopamine model of attention-allocation and learning (Lindskog
et al, 2006
Djurfeldt et al, 2001). It is a self-help chip.
(cont.)
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