Deep brain stimulation shows promise for treating deep depression
16 Feb 2011
Electrical stimulation of targeted areas in the brain has
shown promise for treating patients with the most severe form
Researchers at the University of Bonn together with colleagues in
the US have found potential new targets for deep brain stimulation.
The work has been published in Neuroscience and Biobehavioral
In deep brain stimulation electrodes are implanted in the brain.
Using an electrical pacemaker implanted under the patient’s
clavicle, physicians can influence the function of certain areas of
the brain in a lasting manner. The method was originally developed
for treating patients with Parkinson’s disease, in order to
alleviate the typical movement problems.
For several years, the method has also been investigated in the
treatment of the most severe cases of depression, with striking and
completely unexpected success: in patients who had undergone many
years of unsuccessful treatment, the symptoms sometimes
"Depression does not return in patients who responded to the
stimulation," emphasizes Professor Dr Thomas Schläpfer from the
Bonn Hospital for Psychiatry and Psychotherapy. "The method appears
to have lasting effects — and this is in the case of the most
treatment-resistant patient group described in the literature. This
has never before happened."
Deep brain stimulation has been
tested to date in three different areas of the brain: the nucleus
accumbens, the internal capsule, and a structure known as cg25.
Surprisingly, the effects are nearly identical, regardless of which
of these centres are stimulated.
Together with colleagues from Baltimore and Washington, the Bonn
researchers have since been able to explain why this is the case:
Using a novel tomography method, they were able to make the "cabling
system" of the three brain centres visible. "In doing this, we
determined that at least two of these three areas — probably even
all three — are attached to one and the same cable harness,"
explains the Bonn brain surgeon, Professor Dr. Volker Coenen.
This is the so-called medial forebrain bundle, a structure which
has been known in animals for a long time. The forebrain bundle
forms a kind of feedback loop which allows us to anticipate positive
experiences. "This circuit motivates us to take action," says Coenen.
"In patients with depression, it is apparently disrupted. This
results in, among other things, an extreme lack of drive — a
characteristic symptom of the disease."
accumbens, internal capsule, und cg25 all appear to be connected to
the medial forebrain bundle — rather like leaves are connected to
the branch from which they arise. Whoever stimulates one of these
regions of the brain simultaneously influences the other components
of the motivation circuit to a certain extent.
Coenen, who was the first to anatomically describe the forebrain
bundle in humans, now proposes implanting the electrode for deep
brain stimulation directly into this structure. "We would use the
electrode to send the current pulses to the base of the network and
not to the periphery, as before," explains Schläpfer. "We could thus
potentially work with lower currents and yet achieve greater
A comparatively low-risk procedure
Observations of patients with Parkinson’s disease appear to
support this idea: in this case, a network of brain structures
responsible for movements is stimulated. The more basally
(figuratively speaking: near the branch) the electrical stimulation
is applied, the greater its effect. At the same time, the risk of
adverse side effects is reduced.
By now, more than 80,000 patients with
Parkinson’s disease worldwide have a brain pacemaker in their body.
"Experiences to date demonstrate that the brain intervention
necessary for this is relatively low-risk,” stresses Professor
Coenen. "Thus from a medical point of view, there is nothing that
argues against also using this method to help people with very
1. Coenen VA, Schlaepfer TE, Maedler B, Panksepp J. Cross-Species
Affective Functions of the Medial Forebrain Bundle — Implications
for the Treatment of Affective Pain and Depression in Humans.
Neurosci Biobehav Rev 2010 Dec 21. doi: