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Major depression is a mood disorder that affects nearly 7% of the American population and is the most common cause of disability worldwide. Standard treatment typically involves antidepressant medication alone, although a combination of antidepressant medication and psychological treatment, such as psychotherapy or cognitive-behavioral therapy, is often more effective. However, because depression has genetic, environmental, and psychological contributing factors, treatment can be challenging. Approximately 10% of those suffering from depression have treatment-resistant depression (TRD) that does not respond to standard treatment.A number of treatment options for those with TRD target the functioning of the nervous system. Deep-brain stimulation (DBS) , which is used to treat Parkinson disease, has also been investigated as a treatment for TRD. DBS involves implanting a device in the brain that sends electrical impulses to a specific area. Although the mechanism by which DBS alleviates depressive symptoms is unclear, neurostimulation provided by DBS is thought to disrupt dysfunctional patterns of electrical activity in local areas and connected brain regions.A meta-analysis reviewed the data from several studies that used different brain regions as DBS targets in the treatment of TRD. Table 1 shows the percentage of TRD patients who underwent DBS and showed clinical responsiveness and remission of depression. Clinical response was defined as a 50% reduction in scores on a measure of depression. Various scales were used in the studies, including different versions of the Hamilton Depression Rating Scale (HDRS) and Montgomery-Asberg Depression Rating Scale (MADRS) . Remission of depression was defined as a score that fell below a predetermined threshold.Table 1 Percentage of TRD Patients Who Showed Clinical Response and Remission With DBS Treatment

-Which of the following brain regions is likely the most effective DBS target for a Parkinson disease patient?

Question

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Major depression is a mood disorder that affects nearly 7% of the American population and is the most common cause of disability worldwide. Standard treatment typically involves antidepressant medication alone, although a combination of antidepressant medication and psychological treatment, such as psychotherapy or cognitive-behavioral therapy, is often more effective. However, because depression has genetic, environmental, and psychological contributing factors, treatment can be challenging. Approximately 10% of those suffering from depression have treatment-resistant depression (TRD) that does not respond to standard treatment.A number of treatment options for those with TRD target the functioning of the nervous system. Deep-brain stimulation (DBS) , which is used to treat Parkinson disease, has also been investigated as a treatment for TRD. DBS involves implanting a device in the brain that sends electrical impulses to a specific area. Although the mechanism by which DBS alleviates depressive symptoms is unclear, neurostimulation provided by DBS is thought to disrupt dysfunctional patterns of electrical activity in local areas and connected brain regions.A meta-analysis reviewed the data from several studies that used different brain regions as DBS targets in the treatment of TRD. Table 1 shows the percentage of TRD patients who underwent DBS and showed clinical responsiveness and remission of depression. Clinical response was defined as a 50% reduction in scores on a measure of depression. Various scales were used in the studies, including different versions of the Hamilton Depression Rating Scale (HDRS) and Montgomery-Asberg Depression Rating Scale (MADRS) . Remission of depression was defined as a score that fell below a predetermined threshold.Table 1 Percentage of TRD Patients Who Showed Clinical Response and Remission With DBS Treatment

-Which of the following brain regions is likely the most effective DBS target for a Parkinson disease patient?

Quizplus · Accepted Answer

11ecba2d_0c71_500a_a3bf_81ebfa9808ba_MD0008_00 Parkinson disease is a progressive neurodegenerative disease caused by death of dopaminergic neurons in the substantia nigra, located in the midbrain (mesencephalon). The substantia nigra is part of a group of neural structures collectively known as the basal ganglia, which are involved in the selection and execution of voluntary motor programs. Dopamine has several functions in the central nervous system, including mediating the reward pathway and motor control. The basal ganglia are composed of three dopaminergic pathways: the direct pathway, the indirect pathway, and the nigrostriatal pathway. The direct and indirect pathways have excitatory and inhibitory effects on motor function, respectively, and the nigrostriatal pathway helps maintain the balance between these two pathways. The nigrostriatal pathway is damaged when dopaminergic neurons in the substantia nigra are destroyed. Therefore, the balance between excitatory and inhibitory motor commands deteriorates. Resulting Parkinson symptoms include various motor abnormalities: resting tremor (usually in the upper extremities), muscle rigidity, slowed movement (bradykinesia), shuffling gait, and lack of coordination. DBS in portions of the basal ganglia has been shown to relieve some of these motor symptoms. (Choice A) The amygdala is a neural structure that is part of the limbic system and is involved in emotion regulation and learning (especially fear-based conditioning). (Choice C) The hippocampus is a neural structure that is part of the limbic system and is involved in memory formation, learning, and recall. (Choice D) The motor cortex sends motor commands from the brain to the muscles of the body. DBS of the motor cortex would likely cause disruptions in movement. Educational objective: Parkinson disease is a progressive neurodegenerative disease that involves the loss of dopaminergic neurons in the substantia nigra of the basal ganglia, resulting in motor abnormalities (resting tremor, muscle rigidity, bradykinesia, shuffling gait, lack of coordination) and symptoms of depression.

Passage Major Depression Is a Mood Disorder That Affects Nearly 7