A brain implant for artificial motivation

March 30 2009 / by iPlant / In association with Future Blogger.net
Category: Biotechnology   Year: General   Rating: 7 Hot

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.

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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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Why we should develop electronic modulation of monoamines for human use

April 13 2008 / by iPlant / In association with Future Blogger.net
Category: Biotechnology   Year: General   Rating: 5

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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iPlant seminar video

June 04 2008 / by iPlant / In association with Future Blogger.net
Category: Biotechnology   Year: General   Rating: 4 Hot

part 2 part 3 part 4