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Scientists Propose New Way to Treat Depression With Brain Implants

An x-ray image of someone who had electrodes implanted into their brain to manage their Parkinson's disease. Image: Hellerhoff (Wikimedia…

An x-ray image of someone who had electrodes implanted into their brain to manage their Parkinson’s disease. Image: Hellerhoff (Wikimedia Commons)

In recent years, doctors have explored an unorthodox method to address cases of Depressie die niet heeft gereageerd op andere behandelingen: verzending precieze elektrische schokken direct aan gebieden van een patiëntenbrein, anders bekend als diepe hersenstimulatie (DBS). Terwijl de techniek heeft getoond een aantal beloften, zijn positieve effecten vaak te inconsistent.

But a new study from the University of California, San Francisco, published Thursday in Current Biology, seems to offer an intriguing step forward for DBS as a therapy for depression. Their research suggests there’s another possible target for stimulation, one that might provide more reliable improvements in mood. DBS, even mania.

DBS is commonly used to manage neurological conditions such as Parkinson’s disease and epileptic seizures. These conditions are characterized by variable electrical activity in certain brain regions, and the impulses used in DBS-sent through electrodes implanted in the brain via surgery and controlled by a device also usually implanted in the body elsewhere-are thought to act as a pacemaker , temporarily restoring a healthy brain pattern and easing people’s symptoms. People with depression also tend to have abnormal brain activity, so it’s been theorized that DBS could be helpful for difficult, treatment-resistant cases of depression.

The researchers behind the current study had the opportunity to conduct a unique experiment. De var i stand til at studere 25 patienter med kronisk epilepsi planlægning at undergå en operation som ville midlertidigt implantere elektroder i deres hjerne. De implantaten zouden let dokters uitzoeken waar in de hersenen de patiënten’s aanvallen afkomstig waren, door opnemen van de lokale neurale activiteit van een gericht hersengebied (bij het lokaliseren van de aanvallen, de dokters zouden dan kunnen plannen hoe de veilige delen van the brain at a later time). Men for deres forsøg, var forskerne i stand til at anvende disse samme implantater til hovedsagelig mimic a session of DBS.

The patients had implants placed in various areas of the brain, including near the lateral portion of the orbitofrontal cortex (OFC), a region located right behind the eye. The OFC is known to play a role in decision making, emotion-processing, and mood regulation. And while it’s also implicated in depression, it has not been studied extensively as a stimulation target.

Over the course of several days, the volunteers had different brain regions stimulated via DBS, including the OFC. Soms, de patiënten werden in plaats daarvan gegeven een sham stimulatie, die optrad als een controle. Og efter hver stimuleringssession, de talte om, hvordan de var følte og besvarede spørgeskemaer med det formål at vurdere deres humør.

De patienter havde varierende niveauer af depressionssymptomer, fra minimal til svær (baseret på en almindelig anvendt screening test, de havde taget tidligere to their surgery). Degenen die geen of kleine tekens van depressie hadden geen ervaring moodveranderingen daarna, ongeacht waar de stimulatie plaatsvond of als ze het allemaal ontvangen hebben. Men folk med moderat-til-alvorlige depression symptomer syntes at have deres humør boostet i få minutter efter at have stimulert OFC. And compared to sessions where other brain areas associated with depression were stimulated, these boosts in mood appeared to be more reliable, meaning that as people got bigger shocks, they felt a great boost.

“Our findings are important because they provide a new potential target for treating mood symptoms via brain stimulation therapies, “author Heather Dawes, a co-director of the Systems-Based Neurotechnology for Emerging Therapies program at UCSF, told Gizmodo via email.

The implants also let the researchers record the patients’ brain activity outside of the DBS sessions, which makes them better understand what exactly DBS might have been doing to the OFC. In particular, the brain activity seen after a patient’s sessions seemed to resemble the level of activity seen when the patient was naturally in a good mood.

“This indicates that stimulation may be facilitating natural brain activity underlying positive mood, rather than inducing an unnatural pattern of activity, “said Dawes.

And it did so without causing the pendulum to swing back too far and making the patients hyperactive or manic, a side effect occasionally seen with DBS.

There have already been a few targets established for DBS therapy of depression such as the subgenual cingulate cortex, a brain region commonly linked to emotion and mood regulation. Men studier har ikke vist en konsistent fordel fra DBS behandling. Most notably, a major clinical trial of DBS was terminated early in 2013, after an early analysis showed that the first wave of patients were not improving anywhere near as much as the researchers predicted they would; Some people even got worse.

That trial, while technically a failure, has not closed the door on DBS therapy. Mange patienter i forsøket, som ikke svarede på DBS inden for de første seks måneder, viste betydelige forbedringer på lang sikt, for eksempel. And other clinical trials of DBS are already underway. Men det har ført to spørgsmål om, hvorvidt der er måder å bedre refine behandlingen.

The OFC, because it interacts with other brain regions that coordinate aspects of mood and emotion, might provide a more consistent benefit when stimulated, the team theorizes. There are even limited evidence that non-invasive forms of stimulation (involving electrodes placed on the surface of the head) involving the OFC could also help people with depression.

But for now, there’s still plenty of ground to cover before we can be sure of anything.

“We are really excited by the promising results presented in this paper, but more work is needed before this becomes a clinical treatment,” said Dawes. Die werk zal ook testen of deze effect kan worden gezien bij mensen die klinisch depressief zijn en niet hebben gereageerd op andere behandelingen.

“Er is ook veel werk om te worden gedaan om te zien of deze stimulatie-aanpak kan helpen depressiepatiënten faktisk kommer fra deres sygdom-så langt, vi har kun været i stand til at se på kortvarige effekter, “tilføjede hun. “This is an area we and others will continue to explore.”

[Current Biology]

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