alanhu's blog

Gene therapy and optogenetics are used to treat blindness that was caused by retinitis pigmentosa (RP) and advanced dry-aged related macular degeneration. The two conditions cause the photoreceptors of the retina to die off, gradually. Which would cause difficulty seeing especially in low light. Eventually the loss of vision would be complete and would result in blindness. In the experiment, researches utilized a virus that was modified to contain a gene for an algae called Channelrhodopsin-2 (ChR2). ChR2 is a light sensitive protein. Researchers hypothesized that when ChR2 is injecting into the subjects eye, ChR2 would start expressing and taking over the dead opsins. Since ChR2 is light sensitive, the patient would be able to regain some eyesight, even though it might be in black and white and blurry.

Multiple sclerosis is a neural autoimmune disorder, which causes the body to not recognize its own myelin sheath and attacks it. Myelin wraps around the axons in the spinal cord and brain. Myelin sheath is useful for sending messages passively from one axon to another. The use of myelin sheaths speeds up the process, which allows for quicker messages being sent. Symptoms of multiple sclerosis include fatigue, vision impairment and a loss of coordination. Deep transcranial magnetic stimulation (dTMS) uses a H-shaped magnetic coil to deliver an electric stimulation to the brain nerves. The brain nerves that are targeted are in the prefrontal cortex and primary motor cortex. Which causes the neurons to release neurotransmitters and allows for regulation.

Transcranial direct current stimulation (TDCS) on the brain was used in attempt to find a way to allow stroke patients to recover their motor skills. Strokes are the leading cause of motor impairments in people. A stroke is caused by an interruption of blood supply to the brain. Depending on which part of the brain was affected their motor skills range in severity. Someone who had a stroke would have to go to physical therapy to regain the motor skills that they had before. Though everyone is different, on average a person would be limited for 8 years or more before they can regain their motor efficiency. TDCS would increase the synaptic plasticity, meaning it changes how the neurons are excited. The neurons would have a lower threshold, meaning that it would require less excitatory signals to send a signal. Which would allow the stroke patients to use less effort compared to a healthy human to send a signal for movement. When comparing stroke patients who went through TDCS and patients who did not, it was found that TDCS did not work as planned. The results showed that the retention of motor skills between the use of TDCS and not were equal. Memory of how to do the motor skill were not remembered, just like patients that did go through TDCS. Therefore, TDCS did not improve anything and would be unnecessary as a treatment for stroke patients.

A 23 year old patient with a history of left upper limb dystonic tremor was caused by a stroke in the right thalamus. The dystonic tremors are caused in conjunction with dystonia Dystonia is a neurological disorder where there are excessive muscles that are working all the time without control. Deep brain stimulation is used to deliver small stimulations of electricity to the thalamus. The electrical impulses are sent to the thalamus through a single electrode passing though the right ventralis oralis anterior and the ventralis oralis posterior. The electricity is being used to inhibit the neurons that are firing uncontrollably. The procedure was successful and the 23 year old patient had less tremors than before.  

Repetitive transcranial magnetic stimulation (rTMS) is the use of magnetic coils on the prefrontal cortex to suppress depression. The magnetics are placed on the prefrontal cortex and is non invasive, which means it does not pierce the skin. The magnets target the neurons in the prefrontal cortex and depolarizes them. Which causes those neurons to fire. When those neurons fire it causes more regulation of emotion and depressive symptoms. Which can have an effect on depression as a whole. There are many shapes the coil can be. A figure 8 coil resulted in a 24 % success rate with a 17% remission rate. While a H-1 coil results in a 37% success rate and a 30% remission rate. Though testing has only been done on adults, it is not available and not advised for children and or pregnant women. The procedure is expensive ranging from $6000-$12,000.

Transcranial direct current stimulation (TDCS) on the brain was used in attempt to find a way to allow stroke patients to recover their motor skills. Strokes are the leading cause of motor impairments in people. As a person who had a stroke would have to go to physical therapy to regain the motor skills that they had before. Though everyone is different, on average a person would be limited for 8 years or more before they can regain their motor efficiency. TDCS would increase the synaptic plasticity, meaning it changes how the neurons are excited. The neurons would have a lower threshold, meaning that it would require less excitatory signals to send a signal. When comparing stroke patients who went through TDCS and patients who did not, it was found that TDCS did not work as planned. The results showed that the retention of motor skills between the use of TDCS and not were equal. Therefore, TDCS did not improve anything and would be unnecessary as a treatment for stroke patients.

Transcranial magnetic stimulation (TMS) is the use of magnetic fields to modify brain activity. Schizophrenia symptoms are tied in with the neural activity between the prefrontal cortex and cerebellum. Beth Israel Deaconess Medical Center used transcranial magnetic stimulation in attempt to alleviate schizophrenia symptoms. Patients who went through TMS were found to have an increase in connectivity between the prefrontal cortex and cerebellum. The treatment is new and does not work the same on everyone. The amount of symptoms that were alleviated were different between people.

Anxiety and panic disorders are related to an imbalance in excitatory and inhibitory neurotransmitters. Deep brain stimulation is the process of using electrodes to stimulate the brain. The electrodes send impulses which can create certain signals when stimulated. The experiment was conducted on mice. The anxiety of mice was measured in a maze. The next step was using deep brain stimulation on one group of mice. When both groups of mice were put into the maze again. The mice that received deep brain stimulation was showing lower signs of anxiety and panic. The results of the study shows that using deep brain stimulation can be a way to reduce anxiety and panic in people.