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Electrical recording from deep within the brain

Abnormal electrical activity in the brain triggers OCD and Parkinson's symptoms

Brain stimulation using electrodes. Illustration:
Brain stimulation using electrodes. Illustration:

Obsessive compulsive disorder (OCD) is characterized by intrusive (repetitive) thoughts and compulsive actions. The disturbing thoughts are urges or images that cause distress and anxiety. The compulsive actions are repetitive behaviors (such as washing hands) that are done in response to rigid internal rules or a disturbing thought. The disturbing thoughts and compulsive actions are excessive and illogical, cause a lot of stress and damage the routine of life.

In recent decades, deep brain stimulation (DBS) has begun to be used as a neurosurgical treatment for severe OCD disorder that is resistant to conventional treatments such as drugs and cognitive-behavioral therapy (CBT). In this treatment, tiny electrodes (thickness 1.2 millimeters) are implanted deep in the brain. They are connected to a pacemaker that is implanted under the skin, in the chest or abdomen area. When the pacemaker is activated it produces electrical impulses that are sent to the brain. The attending psychiatrist can direct the method of electrical stimulation and its intensity, depending on the mental state of the patients. In people suffering from OCD (and also in Parkinson's patients) the stimulation is aimed at one of the basic nuclei of the brain - the subthalamic nucleus. This area is related to thoughts, making decisions, planning actions and carrying them out. Many studies have found that it is very essential for the functioning of the brain, so its stimulation may have a significant effect on it.

Dr. Renana Eitan, director of the psychiatric unit at the Tel Aviv Medical Center (Ichilov) and formerly director of the neuropsychiatric unit at the Jerusalem Mental Health Center, is a pioneer in the field of DBS in psychiatry in Israel and around the world. For many years she has been researching the biological basis of psychiatric disorders together with Prof. Hagai Bergman from the Department of Medical Neurobiology at the Hebrew University, in order to find innovative treatments for them. "Our studies and other studies found that the condition of severe OCD patients improved significantly after undergoing DBS," says Dr. Eitan. "The precision in the placement of the electrodes must be maximum. Before the operation, we perform brain mapping on the patient, during which we mark both the target area of ​​the electrodes - the subthalamic nucleus - and the path they will take until they reach it. In addition, during the operation we examine the electrical activity deep in the brain to make sure that we have indeed reached the target area."

Dr. Eitan and her team, with the help of a research grant from the National Science Foundation, examined OCD patients who underwent DBS for about a year with a system that allows electrical recording from deep within the brain. They made electrical recordings during the surgery to implant the electrodes and about a year after, and identified a new and unique neural signature in the subthalamic nucleus; It is a synchronized electrical activity of nerve cells in the emotional and cognitive areas of the nucleus that appears with a unique frequency. Its intensity was found to be related to the arousal of the obsessive-compulsive symptoms and their intensity. The researchers also examined a group of Parkinson's patients who underwent DBS in the same brain area as a treatment for their disease - they also made electrical recordings during surgery and discovered a similar neural signature.

Dr. Eitan: "This finding can be used by us in the future to create a better DBS system for patients with OCD, and also for Parkinson's patients, which will identify the abnormal electrical activity in the subthalamic nucleus and create a unique stimulus that will change it."

Life itself:

Dr. Renana Eitan, 44 years old, married to Amos, mother of three daughters and lives in Jerusalem.

More of the topic in Hayadan:

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